G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
neurexin 1
G00001103 (Mus musculus)

Databases (7)

ENSG00000179915 (Ensembl human gene)
9378 (Entrez Gene)
1074 (G2Cdb plasticity & disease)
NRXN1 (GeneCards)
600565 (OMIM)
Marker Symbol
HGNC:8008 (HGNC)
Protein Sequence
Q9ULB1 (UniProt)

Synonyms (2)

  • Hs.22998
  • KIAA0578

Literature (43)

Pubmed - other

  • Copy number variation in schizophrenia in the Japanese population.

    Ikeda M, Aleksic B, Kirov G, Kinoshita Y, Yamanouchi Y, Kitajima T, Kawashima K, Okochi T, Kishi T, Zaharieva I, Owen MJ, O'Donovan MC, Ozaki N and Iwata N

    Medical Research Council (MRC) Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Cardiff CF14 4XN, United Kingdom.

    Background: Copy number variants (CNVs) have been shown to increase the risk to develop schizophrenia. The best supported findings are at 1q21.1, 15q11.2, 15q13.3, and 22q11.2 and deletions at the gene neurexin 1 (NRXN1).

    Methods: In this study, we used Affymetrix 5.0 arrays to investigate the role of rare CNVs in 575 patients with schizophrenia and 564 control subjects from Japan.

    Results: There was a nonsignificant trend for excess of rare CNVs in schizophrenia (p = .087); however, we did not confirm the previously implicated association for very large CNVs (>500 kilobase [kb]) in this population. We provide support for three previous findings in schizophrenia, as we identified one deletion in a case at 1q21.1, one deletion within NRXN1, and four duplications in cases and one in a control subject at 16p13.1, a locus first implicated in autism and later in schizophrenia.

    Conclusions: In this population, we support some of the previous findings in schizophrenia but could not find an increased burden of very large (>500 kb) CNVs, which was proposed recently. However, we provide support for the role of CNVs at 16p13.1, 1q21.1, and NRXN1.

    Funded by: Medical Research Council: G0800509; NIMH NIH HHS: 2 P50 MH066392-05A1, P50 MH066392

    Biological psychiatry 2010;67;3;283-6

  • Three-way translocation involving MLL, MLLT1, and a novel third partner, NRXN1, in a patient with acute lymphoblastic leukemia and t(2;19;11) (p12;p13.3;q23).

    Lee SG, Park TS, Won SC, Song J, Lee KA, Choi JR, Marschalek R and Meyer C

    Department of Laboratory Medicine, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, Korea.

    Translocations involving mixed lineage leukemia (MLL) gene at 11q23 are associated with de novo acute leukemia as well as therapy-related acute leukemia. More than 100 different translocations involving MLL have been described in acute leukemia, with more than 60 translocation partner genes characterized on the molecular level. In addition to various simple translocations affecting MLL, there are also complex forms involving three or more chromosomes. Here, we describe a novel three-way translocation of t(2;19;11)(p12;p13.3;q23) in a patient with acute lymphoblastic leukemia (ALL). In this translocation, the distal 19p13.3 joins the proximal 11q23 on der(11), whereas the distal 11q23 is translocated to 2p12. Three-way translocations involving 11q23 are often difficult to detect with cytogenetic means alone. In the present case, however, the chromosomes involved in the three-way translocation were readily identifiable by GTG banding. The MLL-MLLT1 fusion products from the derivative chromosome 11 were detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and two splicing variant forms were confirmed by cloning and sequencing. Furthermore, the novel third partner gene, NRXN1, was detected by systematic breakpoint analysis using long-distance inverse-PCR methods (LDI-PCR). The apparent three-way translocation thus identified is noteworthy because few studies have reported complex rearrangements involving 11q23 and 19p13.3 in acute leukemias.

    Cancer genetics and cytogenetics 2010;197;1;32-8

  • A genome-wide study of common SNPs and CNVs in cognitive performance in the CANTAB.

    Need AC, Attix DK, McEvoy JM, Cirulli ET, Linney KL, Hunt P, Ge D, Heinzen EL, Maia JM, Shianna KV, Weale ME, Cherkas LF, Clement G, Spector TD, Gibson G and Goldstein DB

    Center for Human Genome Variation, Institute for Genome Sciences and Policy, Duke University, 450 Research Drive, Box 91009, Durham, NC 27708, USA.

    Psychiatric disorders such as schizophrenia are commonly accompanied by cognitive impairments that are treatment resistant and crucial to functional outcome. There has been great interest in studying cognitive measures as endophenotypes for psychiatric disorders, with the hope that their genetic basis will be clearer. To investigate this, we performed a genome-wide association study involving 11 cognitive phenotypes from the Cambridge Neuropsychological Test Automated Battery. We showed these measures to be heritable by comparing the correlation in 100 monozygotic and 100 dizygotic twin pairs. The full battery was tested in approximately 750 subjects, and for spatial and verbal recognition memory, we investigated a further 500 individuals to search for smaller genetic effects. We were unable to find any genome-wide significant associations with either SNPs or common copy number variants. Nor could we formally replicate any polymorphism that has been previously associated with cognition, although we found a weak signal of lower than expected P-values for variants in a set of 10 candidate genes. We additionally investigated SNPs in genomic loci that have been shown to harbor rare variants that associate with neuropsychiatric disorders, to see if they showed any suggestion of association when considered as a separate set. Only NRXN1 showed evidence of significant association with cognition. These results suggest that common genetic variation does not strongly influence cognition in healthy subjects and that cognitive measures do not represent a more tractable genetic trait than clinical endpoints such as schizophrenia. We discuss a possible role for rare variation in cognitive genomics.

    Funded by: Biotechnology and Biological Sciences Research Council: G20234; Wellcome Trust

    Human molecular genetics 2009;18;23;4650-61

  • CNTNAP2 and NRXN1 are mutated in autosomal-recessive Pitt-Hopkins-like mental retardation and determine the level of a common synaptic protein in Drosophila.

    Zweier C, de Jong EK, Zweier M, Orrico A, Ousager LB, Collins AL, Bijlsma EK, Oortveld MA, Ekici AB, Reis A, Schenck A and Rauch A

    Institute of Human Genetics, Friedrich Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany. czweier@humgenet.uni-erlangen.de

    Heterozygous copy-number variants and SNPs of CNTNAP2 and NRXN1, two distantly related members of the neurexin superfamily, have been repeatedly associated with a wide spectrum of neuropsychiatric disorders, such as developmental language disorders, autism spectrum disorders, epilepsy, and schizophrenia. We now identified homozygous and compound-heterozygous deletions and mutations via molecular karyotyping and mutational screening in CNTNAP2 and NRXN1 in four patients with severe mental retardation (MR) and variable features, such as autistic behavior, epilepsy, and breathing anomalies, phenotypically overlapping with Pitt-Hopkins syndrome. With a frequency of at least 1% in our cohort of 179 patients, recessive defects in CNTNAP2 appear to significantly contribute to severe MR. Whereas the established synaptic role of NRXN1 suggests that synaptic defects contribute to the associated neuropsychiatric disorders and to severe MR as reported here, evidence for a synaptic role of the CNTNAP2-encoded protein CASPR2 has so far been lacking. Using Drosophila as a model, we now show that, as known for fly Nrx-I, the CASPR2 ortholog Nrx-IV might also localize to synapses. Overexpression of either protein can reorganize synaptic morphology and induce increased density of active zones, the synaptic domains of neurotransmitter release. Moreover, both Nrx-I and Nrx-IV determine the level of the presynaptic active-zone protein bruchpilot, indicating a possible common molecular mechanism in Nrx-I and Nrx-IV mutant conditions. We therefore propose that an analogous shared synaptic mechanism contributes to the similar clinical phenotypes resulting from defects in human NRXN1 and CNTNAP2.

    American journal of human genetics 2009;85;5;655-66

  • Identification of new putative susceptibility genes for several psychiatric disorders by association analysis of regulatory and non-synonymous SNPs of 306 genes involved in neurotransmission and neurodevelopment.

    Gratacòs M, Costas J, de Cid R, Bayés M, González JR, Baca-García E, de Diego Y, Fernández-Aranda F, Fernández-Piqueras J, Guitart M, Martín-Santos R, Martorell L, Menchón JM, Roca M, Sáiz-Ruiz J, Sanjuán J, Torrens M, Urretavizcaya M, Valero J, Vilella E, Estivill X, Carracedo A and Psychiatric Genetics Network Group

    CIBER en Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Madrid, Spain.

    A fundamental difficulty in human genetics research is the identification of the spectrum of genetic variants that contribute to the susceptibility to common/complex disorders. We tested here the hypothesis that functional genetic variants may confer susceptibility to several related common disorders. We analyzed five main psychiatric diagnostic categories (substance-abuse, anxiety, eating, psychotic, and mood disorders) and two different control groups, representing a total of 3,214 samples, for 748 promoter and non-synonymous single nucleotide polymorphisms (SNPs) at 306 genes involved in neurotransmission and/or neurodevelopment. We identified strong associations to individual disorders, such as growth hormone releasing hormone (GHRH) with anxiety disorders, prolactin regulatory element (PREB) with eating disorders, ionotropic kainate glutamate receptor 5 (GRIK5) with bipolar disorder and several SNPs associated to several disorders, that may represent individual and related disease susceptibility factors. Remarkably, a functional SNP, rs945032, located in the promoter region of the bradykinin receptor B2 gene (BDKRB2) was associated to three disorders (panic disorder, substance abuse, and bipolar disorder), and two additional BDKRB2 SNPs to obsessive-compulsive disorder and major depression, providing evidence for common variants of susceptibility to several related psychiatric disorders. The association of BDKRB2 (odd ratios between 1.65 and 3.06) to several psychiatric disorders supports the view that a common genetic variant could confer susceptibility to clinically related phenotypes, and defines a new functional hint in the pathophysiology of psychiatric diseases.

    American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics 2009;150B;6;808-16

  • Neurexin 1 (NRXN1) deletions in schizophrenia.

    Kirov G, Rujescu D, Ingason A, Collier DA, O'Donovan MC and Owen MJ

    Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Department of Psychological Medicine and Neurology, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK. kirov@cardiff.ac.uk

    Funded by: Medical Research Council: MRC_G0800509

    Schizophrenia bulletin 2009;35;5;851-4

  • Recurrent rearrangements in synaptic and neurodevelopmental genes and shared biologic pathways in schizophrenia, autism, and mental retardation.

    Guilmatre A, Dubourg C, Mosca AL, Legallic S, Goldenberg A, Drouin-Garraud V, Layet V, Rosier A, Briault S, Bonnet-Brilhault F, Laumonnier F, Odent S, Le Vacon G, Joly-Helas G, David V, Bendavid C, Pinoit JM, Henry C, Impallomeni C, Germano E, Tortorella G, Di Rosa G, Barthelemy C, Andres C, Faivre L, Frébourg T, Saugier Veber P and Campion D

    Institut National de la Santé et de la Recherche Médicale, Unité 614, Institut Hospitalo-Universitaire de Recherche Biomédicale, 76000 Rouen, France.

    Context: Results of comparative genomic hybridization studies have suggested that rare copy number variations (CNVs) at numerous loci are involved in the cause of mental retardation, autism spectrum disorders, and schizophrenia.

    Objectives: To provide an estimate of the collective frequency of a set of recurrent or overlapping CNVs in 3 different groups of cases compared with healthy control subjects and to assess whether each CNV is present in more than 1 clinical category.

    Design: Case-control study.

    Setting: Academic research.

    Participants: We investigated 28 candidate loci previously identified by comparative genomic hybridization studies for gene dosage alteration in 247 cases with mental retardation, in 260 cases with autism spectrum disorders, in 236 cases with schizophrenia or schizoaffective disorder, and in 236 controls.

    Collective and individual frequencies of the analyzed CNVs in cases compared with controls.

    Results: Recurrent or overlapping CNVs were found in cases at 39.3% of the selected loci. The collective frequency of CNVs at these loci is significantly increased in cases with autism, in cases with schizophrenia, and in cases with mental retardation compared with controls (P < .001, P = .01, and P = .001, respectively, Fisher exact test). Individual significance (P = .02 without correction for multiple testing) was reached for the association between autism and a 350-kilobase deletion located at 22q11 and spanning the PRODH and DGCR6 genes.

    Conclusions: Weakly to moderately recurrent CNVs (transmitted or occurring de novo) seem to be causative or contributory factors for these diseases. Most of these CNVs (which contain genes involved in neurotransmission or in synapse formation and maintenance) are present in the 3 pathologic conditions (schizophrenia, autism, and mental retardation), supporting the existence of shared biologic pathways in these neurodevelopmental disorders.

    Archives of general psychiatry 2009;66;9;947-56

  • Genome-wide analyses of exonic copy number variants in a family-based study point to novel autism susceptibility genes.

    Bucan M, Abrahams BS, Wang K, Glessner JT, Herman EI, Sonnenblick LI, Alvarez Retuerto AI, Imielinski M, Hadley D, Bradfield JP, Kim C, Gidaya NB, Lindquist I, Hutman T, Sigman M, Kustanovich V, Lajonchere CM, Singleton A, Kim J, Wassink TH, McMahon WM, Owley T, Sweeney JA, Coon H, Nurnberger JI, Li M, Cantor RM, Minshew NJ, Sutcliffe JS, Cook EH, Dawson G, Buxbaum JD, Grant SF, Schellenberg GD, Geschwind DH and Hakonarson H

    Autism Genetic Resource Exchange, Autism Speaks, Los Angeles, California, United States of America.

    The genetics underlying the autism spectrum disorders (ASDs) is complex and remains poorly understood. Previous work has demonstrated an important role for structural variation in a subset of cases, but has lacked the resolution necessary to move beyond detection of large regions of potential interest to identification of individual genes. To pinpoint genes likely to contribute to ASD etiology, we performed high density genotyping in 912 multiplex families from the Autism Genetics Resource Exchange (AGRE) collection and contrasted results to those obtained for 1,488 healthy controls. Through prioritization of exonic deletions (eDels), exonic duplications (eDups), and whole gene duplication events (gDups), we identified more than 150 loci harboring rare variants in multiple unrelated probands, but no controls. Importantly, 27 of these were confirmed on examination of an independent replication cohort comprised of 859 cases and an additional 1,051 controls. Rare variants at known loci, including exonic deletions at NRXN1 and whole gene duplications encompassing UBE3A and several other genes in the 15q11-q13 region, were observed in the course of these analyses. Strong support was likewise observed for previously unreported genes such as BZRAP1, an adaptor molecule known to regulate synaptic transmission, with eDels or eDups observed in twelve unrelated cases but no controls (p = 2.3x10(-5)). Less is known about MDGA2, likewise observed to be case-specific (p = 1.3x10(-4)). But, it is notable that the encoded protein shows an unexpectedly high similarity to Contactin 4 (BLAST E-value = 3x10(-39)), which has also been linked to disease. That hundreds of distinct rare variants were each seen only once further highlights complexity in the ASDs and points to the continued need for larger cohorts.

    Funded by: NCRR NIH HHS: UL1 RR024134, UL1-RR024134-03; NIA NIH HHS: 1 Z01 AG000949-02, Z01 AG000949; NICHD NIH HHS: P50 HD055784, P50HD055784-01; NIGMS NIH HHS: P20 GM069012, P20-GM69012; NIMH NIH HHS: 1U24MH081810, MH081754, R01 MH081754, R01MH604687, U24 MH081810

    PLoS genetics 2009;5;6;e1000536

  • Disruption of the neurexin 1 gene is associated with schizophrenia.

    Rujescu D, Ingason A, Cichon S, Pietiläinen OP, Barnes MR, Toulopoulou T, Picchioni M, Vassos E, Ettinger U, Bramon E, Murray R, Ruggeri M, Tosato S, Bonetto C, Steinberg S, Sigurdsson E, Sigmundsson T, Petursson H, Gylfason A, Olason PI, Hardarsson G, Jonsdottir GA, Gustafsson O, Fossdal R, Giegling I, Möller HJ, Hartmann AM, Hoffmann P, Crombie C, Fraser G, Walker N, Lonnqvist J, Suvisaari J, Tuulio-Henriksson A, Djurovic S, Melle I, Andreassen OA, Hansen T, Werge T, Kiemeney LA, Franke B, Veltman J, Buizer-Voskamp JE, GROUP Investigators, Sabatti C, Ophoff RA, Rietschel M, Nöthen MM, Stefansson K, Peltonen L, St Clair D, Stefansson H and Collier DA

    Division of Molecular and Clinical Neurobiology, Department of Psychiatry, Ludwig- Maximilians University, Munich, Germany.

    Deletions within the neurexin 1 gene (NRXN1; 2p16.3) are associated with autism and have also been reported in two families with schizophrenia. We examined NRXN1, and the closely related NRXN2 and NRXN3 genes, for copy number variants (CNVs) in 2977 schizophrenia patients and 33 746 controls from seven European populations (Iceland, Finland, Norway, Germany, The Netherlands, Italy and UK) using microarray data. We found 66 deletions and 5 duplications in NRXN1, including a de novo deletion: 12 deletions and 2 duplications occurred in schizophrenia cases (0.47%) compared to 49 and 3 (0.15%) in controls. There was no common breakpoint and the CNVs varied from 18 to 420 kb. No CNVs were found in NRXN2 or NRXN3. We performed a Cochran-Mantel-Haenszel exact test to estimate association between all CNVs and schizophrenia (P = 0.13; OR = 1.73; 95% CI 0.81-3.50). Because the penetrance of NRXN1 CNVs may vary according to the level of functional impact on the gene, we next restricted the association analysis to CNVs that disrupt exons (0.24% of cases and 0.015% of controls). These were significantly associated with a high odds ratio (P = 0.0027; OR 8.97, 95% CI 1.8-51.9). We conclude that NRXN1 deletions affecting exons confer risk of schizophrenia.

    Funded by: Department of Health: DH_PDA/02/06/016; Medical Research Council: MRC_G0901310; Wellcome Trust: WT089061

    Human molecular genetics 2009;18;5;988-96

  • A genome-wide investigation of SNPs and CNVs in schizophrenia.

    Need AC, Ge D, Weale ME, Maia J, Feng S, Heinzen EL, Shianna KV, Yoon W, Kasperaviciūte D, Gennarelli M, Strittmatter WJ, Bonvicini C, Rossi G, Jayathilake K, Cola PA, McEvoy JP, Keefe RS, Fisher EM, St Jean PL, Giegling I, Hartmann AM, Möller HJ, Ruppert A, Fraser G, Crombie C, Middleton LT, St Clair D, Roses AD, Muglia P, Francks C, Rujescu D, Meltzer HY and Goldstein DB

    Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina, USA.

    We report a genome-wide assessment of single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) in schizophrenia. We investigated SNPs using 871 patients and 863 controls, following up the top hits in four independent cohorts comprising 1,460 patients and 12,995 controls, all of European origin. We found no genome-wide significant associations, nor could we provide support for any previously reported candidate gene or genome-wide associations. We went on to examine CNVs using a subset of 1,013 cases and 1,084 controls of European ancestry, and a further set of 60 cases and 64 controls of African ancestry. We found that eight cases and zero controls carried deletions greater than 2 Mb, of which two, at 8p22 and 16p13.11-p12.4, are newly reported here. A further evaluation of 1,378 controls identified no deletions greater than 2 Mb, suggesting a high prior probability of disease involvement when such deletions are observed in cases. We also provide further evidence for some smaller, previously reported, schizophrenia-associated CNVs, such as those in NRXN1 and APBA2. We could not provide strong support for the hypothesis that schizophrenia patients have a significantly greater "load" of large (>100 kb), rare CNVs, nor could we find common CNVs that associate with schizophrenia. Finally, we did not provide support for the suggestion that schizophrenia-associated CNVs may preferentially disrupt genes in neurodevelopmental pathways. Collectively, these analyses provide the first integrated study of SNPs and CNVs in schizophrenia and support the emerging view that rare deleterious variants may be more important in schizophrenia predisposition than common polymorphisms. While our analyses do not suggest that implicated CNVs impinge on particular key pathways, we do support the contribution of specific genomic regions in schizophrenia, presumably due to recurrent mutation. On balance, these data suggest that very few schizophrenia patients share identical genomic causation, potentially complicating efforts to personalize treatment regimens.

    Funded by: Medical Research Council: MRC_G0400149

    PLoS genetics 2009;5;2;e1000373

  • Association of a polymorphism in the NRXN3 gene with the degree of smoking in schizophrenia: a preliminary study.

    Novak G, Boukhadra J, Shaikh SA, Kennedy JL and Le Foll B

    Translational Addiction Research Laboratory, Centre for Addiction and Mental Health and The University of Toronto, Toronto, Ontario, Canada.

    Whole genome scan studies have recently identified the NRXN1 and NRXN3 genes as potential contributing factors in the risk for nicotine addiction. We have genotyped 15 single nucleotide polymorphisms (SNPs) spanning the NRXN1 and NRXN3 genes in 195 unrelated patients with schizophrenia for whom information about their smoking status and number of cigarettes smoked per day (CPD) was obtained. The NRXN3 marker rs1004212 was significantly associated with quantity of tobacco smoked. Individuals homozygous for the C allele of rs1004212 smoked more cigarettes per day than heterozygous individuals. We found no significant association of markers within the NRXN1 gene with the risk of smoking or the quantity of tobacco smoked. Because of the relatively small sample size, this is a preliminary study. However, this candidate gene study supports the observations of molecular studies implicating the NRXN genes in drug addiction and suggests that variants in the NRXN3 gene could contribute to the degree of nicotine dependence in patients with schizophrenia.

    The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry 2009;10;4 Pt 3;929-35

  • Recurrent CNVs disrupt three candidate genes in schizophrenia patients.

    Vrijenhoek T, Buizer-Voskamp JE, van der Stelt I, Strengman E, Genetic Risk and Outcome in Psychosis (GROUP) Consortium, Sabatti C, Geurts van Kessel A, Brunner HG, Ophoff RA and Veltman JA

    Department of Human Genetics, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.

    Schizophrenia is a severe psychiatric disease with complex etiology, affecting approximately 1% of the general population. Most genetics studies so far have focused on disease association with common genetic variation, such as single-nucleotide polymorphisms (SNPs), but it has recently become apparent that large-scale genomic copy-number variants (CNVs) are involved in disease development as well. To assess the role of rare CNVs in schizophrenia, we screened 54 patients with deficit schizophrenia using Affymetrix's GeneChip 250K SNP arrays. We identified 90 CNVs in total, 77 of which have been reported previously in unaffected control cohorts. Among the genes disrupted by the remaining rare CNVs are MYT1L, CTNND2, NRXN1, and ASTN2, genes that play an important role in neuronal functioning but--except for NRXN1--have not been associated with schizophrenia before. We studied the occurrence of CNVs at these four loci in an additional cohort of 752 patients and 706 normal controls from The Netherlands. We identified eight additional CNVs, of which the four that affect coding sequences were found only in the patient cohort. Our study supports a role for rare CNVs in schizophrenia susceptibility and identifies at least three candidate genes for this complex disorder.

    Funded by: PHS HHS: R01 MG078075

    American journal of human genetics 2008;83;4;504-10

  • Neurexin 1alpha structural variants associated with autism.

    Yan J, Noltner K, Feng J, Li W, Schroer R, Skinner C, Zeng W, Schwartz CE and Sommer SS

    Department of Molecular Genetics, City of Hope National Medical Center, 1500 East Duarte Road, Duarte, CA 91010-3000, USA.

    Neurexins are presynaptic membrane cell-adhesion molecules which bind to neuroligins, a family of proteins that are associated with autism. To explore the possibility that structural variants in the neurexin alpha genes predispose to autism, the coding regions and associated splice junctions of the neurexin 1alpha gene were sequenced in 116 Caucasian patients with autism and 192 Caucasian controls. Five ultra-rare structural variants including a predicted splicing mutation were found in patients with autism and absent in 10,000 control alleles. Only one ultra-rare structural variant was found in controls (5/116 vs. 1/192; P=0.03, Fisher's exact test, one-sided). In the context of all available data, the ultra-rare structural variants of the neurexin 1alpha gene are consistent with mutations predisposing to autism.

    Neuroscience letters 2008;438;3;368-70

  • Significant association of the neurexin-1 gene (NRXN1) with nicotine dependence in European- and African-American smokers.

    Nussbaum J, Xu Q, Payne TJ, Ma JZ, Huang W, Gelernter J and Li MD

    Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, USA.

    The neurexin-1 gene (NRXN1) has been shown to play a fundamental role in synaptogenesis and synaptic maintenance, as well as Ca(2+) channel and NMDA receptor recruitment. A recent study reported that NRXN1 is associated with nicotine dependence (ND); this, together with the intriguing physiological functions of the gene, motivated us to investigate the involvement of NRXN1 with ND in independent samples. In this study, we analyzed 21 single nucleotide polymorphisms (SNPs) within NRXN1 for association with ND, which was assessed by smoking quantity (SQ), the heaviness of smoking index (HSI) and the Fagerström test for ND (FTND). Individual SNP and haplotype association tests were carried out in a sample consisting of 2037 individuals from 602 nuclear families of African-American (AA) or European-American (EA) origin. Individual SNP analysis revealed significant associations of rs2193225 with SQ, HSI and FTND (P = 0.00014-0.0010) in the EA sample and with SQ (P = 0.0019) in the pooled sample under the dominant model and rs6721498 with SQ, HSI and FTND in the AA (P = 0.000090-0.0000086) and pooled (P = 0.0010-0.00099) samples under the additive model, following correction for multiple testing. Haplotype analysis revealed six major haplotypes in the AA sample (minimum P-value = 0.000079), one major haplotype in the EA sample (P = 0.0062) and five major haplotypes in the pooled sample (minimum P-value = 0.00083), which showed significant association with all three ND measures; all of these contained one specific allele from one of the two aforementioned SNPs. Based on our findings that NRXN1 has significant association with ND in two independent samples, recent findings that NRXN1 plays an important role in synaptic development, and the previous report of association, we conclude that this gene represents a strong candidate for involvement in the etiology of ND.

    Funded by: NIDA NIH HHS: DA-12844, DA-12849

    Human molecular genetics 2008;17;11;1569-77

  • Comparative genome hybridization suggests a role for NRXN1 and APBA2 in schizophrenia.

    Kirov G, Gumus D, Chen W, Norton N, Georgieva L, Sari M, O'Donovan MC, Erdogan F, Owen MJ, Ropers HH and Ullmann R

    Department of Psychological Medicine, Cardiff University, Henry Wellcome Building, Heath Park, Cardiff CF14 4XN, UK.

    Copy number variations (CNVs) account for a substantial proportion of human genomic variation, and have been shown to cause neurodevelopmental disorders. We sought to determine the relevance of CNVs to the aetiology of schizophrenia (SZ). Whole-genome, high-resolution, tiling path BAC array comparative genomic hybridization (array CGH) was employed to test DNA from 93 individuals with DSM-IV SZ. Common DNA copy number changes that are unlikely to be directly pathogenic in SZ were filtered out by comparison to a reference dataset of 372 control individuals analyzed in our laboratory, and a screen against the Database of Genomic Variants. The remaining aberrations were validated with Affymetrix 250K SNP arrays or 244K Agilent oligo-arrays and tested for inheritance from the parents. A total of 13 aberrations satisfied our criteria. Two of them are very likely to be pathogenic. The first one is a deletion at 2p16.3 that was present in an affected sibling and disrupts NRXN1. The second one is a de novo duplication at 15q13.1 spanning APBA2. The proteins of these two genes interact directly and play a role in synaptic development and function. Both genes have been affected by CNVs in patients with autism and mental retardation, but neither has been previously implicated in SZ.

    Funded by: Medical Research Council: G9309834, G9810900

    Human molecular genetics 2008;17;3;458-65

  • Disruption of neurexin 1 associated with autism spectrum disorder.

    Kim HG, Kishikawa S, Higgins AW, Seong IS, Donovan DJ, Shen Y, Lally E, Weiss LA, Najm J, Kutsche K, Descartes M, Holt L, Braddock S, Troxell R, Kaplan L, Volkmar F, Klin A, Tsatsanis K, Harris DJ, Noens I, Pauls DL, Daly MJ, MacDonald ME, Morton CC, Quade BJ and Gusella JF

    Molecular Neurogenetics Unit, Center for Human Genetic Research and Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.

    Autism is a neurodevelopmental disorder of complex etiology in which genetic factors play a major role. We have implicated the neurexin 1 (NRXN1) gene in two independent subjects who display an autism spectrum disorder (ASD) in association with a balanced chromosomal abnormality involving 2p16.3. In the first, with karyotype 46,XX,ins(16;2)(q22.1;p16.1p16.3)pat, NRXN1 is directly disrupted within intron 5. Importantly, the father possesses the same chromosomal abnormality in the absence of ASD, indicating that the interruption of alpha-NRXN1 is not fully penetrant and must interact with other factors to produce ASD. The breakpoint in the second subject, with 46,XY,t(1;2)(q31.3;p16.3)dn, occurs approximately 750 kb 5' to NRXN1 within a 2.6 Mb genomic segment that harbors no currently annotated genes. A scan of the NRXN1 coding sequence in a cohort of ASD subjects, relative to non-ASD controls, revealed that amino acid alterations in neurexin 1 are not present at high frequency in ASD. However, a number of rare sequence variants in the coding region, including two missense changes in conserved residues of the alpha-neurexin 1 leader sequence and of an epidermal growth factor (EGF)-like domain, respectively, suggest that even subtle changes in NRXN1 might contribute to susceptibility to ASD.

    Funded by: NICHD NIH HHS: P01-HD00300838, U19 HD035482, U19-HD35482; NIGMS NIH HHS: P01 GM061354, P01-GM061354; NIMH NIH HHS: MH64547, R01 MH064547; NINDS NIH HHS: R01 NS016648, R01-NS16648

    American journal of human genetics 2008;82;1;199-207

  • Novel genes identified in a high-density genome wide association study for nicotine dependence.

    Bierut LJ, Madden PA, Breslau N, Johnson EO, Hatsukami D, Pomerleau OF, Swan GE, Rutter J, Bertelsen S, Fox L, Fugman D, Goate AM, Hinrichs AL, Konvicka K, Martin NG, Montgomery GW, Saccone NL, Saccone SF, Wang JC, Chase GA, Rice JP and Ballinger DG

    Department of Psychiatry, Washington University School of Medicine, 660 South Euclid, Box 8134, St Louis, MO 63110, USA. bierut@msnotes.wustl.edu

    Tobacco use is a leading contributor to disability and death worldwide, and genetic factors contribute in part to the development of nicotine dependence. To identify novel genes for which natural variation contributes to the development of nicotine dependence, we performed a comprehensive genome wide association study using nicotine dependent smokers as cases and non-dependent smokers as controls. To allow the efficient, rapid, and cost effective screen of the genome, the study was carried out using a two-stage design. In the first stage, genotyping of over 2.4 million single nucleotide polymorphisms (SNPs) was completed in case and control pools. In the second stage, we selected SNPs for individual genotyping based on the most significant allele frequency differences between cases and controls from the pooled results. Individual genotyping was performed in 1050 cases and 879 controls using 31 960 selected SNPs. The primary analysis, a logistic regression model with covariates of age, gender, genotype and gender by genotype interaction, identified 35 SNPs with P-values less than 10(-4) (minimum P-value 1.53 x 10(-6)). Although none of the individual findings is statistically significant after correcting for multiple tests, additional statistical analyses support the existence of true findings in this group. Our study nominates several novel genes, such as Neurexin 1 (NRXN1), in the development of nicotine dependence while also identifying a known candidate gene, the beta3 nicotinic cholinergic receptor. This work anticipates the future directions of large-scale genome wide association studies with state-of-the-art methodological approaches and sharing of data with the scientific community.

    Funded by: NCI NIH HHS: CA89392, P01 CA089392, P01 CA089392-05; NIDA NIH HHS: DA015129, DA12854, K01 DA015129, N01DA-0-7079, R01 DA012854, R56 DA012854

    Human molecular genetics 2007;16;1;24-35

  • Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes.

    Kimura K, Wakamatsu A, Suzuki Y, Ota T, Nishikawa T, Yamashita R, Yamamoto J, Sekine M, Tsuritani K, Wakaguri H, Ishii S, Sugiyama T, Saito K, Isono Y, Irie R, Kushida N, Yoneyama T, Otsuka R, Kanda K, Yokoi T, Kondo H, Wagatsuma M, Murakawa K, Ishida S, Ishibashi T, Takahashi-Fujii A, Tanase T, Nagai K, Kikuchi H, Nakai K, Isogai T and Sugano S

    Life Science Research Laboratory, Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, 185-8601, Japan.

    By analyzing 1,780,295 5'-end sequences of human full-length cDNAs derived from 164 kinds of oligo-cap cDNA libraries, we identified 269,774 independent positions of transcriptional start sites (TSSs) for 14,628 human RefSeq genes. These TSSs were clustered into 30,964 clusters that were separated from each other by more than 500 bp and thus are very likely to constitute mutually distinct alternative promoters. To our surprise, at least 7674 (52%) human RefSeq genes were subject to regulation by putative alternative promoters (PAPs). On average, there were 3.1 PAPs per gene, with the composition of one CpG-island-containing promoter per 2.6 CpG-less promoters. In 17% of the PAP-containing loci, tissue-specific use of the PAPs was observed. The richest tissue sources of the tissue-specific PAPs were testis and brain. It was also intriguing that the PAP-containing promoters were enriched in the genes encoding signal transduction-related proteins and were rarer in the genes encoding extracellular proteins, possibly reflecting the varied functional requirement for and the restricted expression of those categories of genes, respectively. The patterns of the first exons were highly diverse as well. On average, there were 7.7 different splicing types of first exons per locus partly produced by the PAPs, suggesting that a wide variety of transcripts can be achieved by this mechanism. Our findings suggest that use of alternate promoters and consequent alternative use of first exons should play a pivotal role in generating the complexity required for the highly elaborated molecular systems in humans.

    Genome research 2006;16;1;55-65

  • Dissection of synapse induction by neuroligins: effect of a neuroligin mutation associated with autism.

    Chubykin AA, Liu X, Comoletti D, Tsigelny I, Taylor P and Südhof TC

    Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center at Dallas, 6000 Harry Hines Boulevard, Dallas, TX 75390-9111, USA.

    To study synapse formation by neuroligins, we co-cultured hippocampal neurons with COS cells expressing wild type and mutant neuroligins. The large size of COS cells makes it possible to test the effect of neuroligins presented over an extended surface area. We found that a uniform lawn of wild type neuroligins displayed on the cell surface triggers the formation of hundreds of uniformly sized, individual synaptic contacts that are labeled with neurexin antibodies. Electron microscopy revealed that these artificial synapses contain a presynaptic active zone with docked vesicles and often feature a postsynaptic density. Neuroligins 1, 2, and 3 were active in this assay. Mutations in two surface loops of neuroligin 1 abolished neuroligin binding to neurexin 1beta, a presumptive presynaptic binding partner for postsynaptic neuroligins, and blocked synapse formation. An analysis of mutant neuroligins with an amino acid substitution that corresponds to a mutation described in patients with an autistic syndrome confirmed previous reports that these mutant neuroligins have a compromised capacity to be transported to the cell surface. Nevertheless, the small percentage of mutant neuroligins that reached the cell surface still induced synapse formation. Viewed together, our data suggest that neuroligins generally promote artificial synapse formation in a manner that is associated with beta-neurexin binding and results in morphologically well differentiated synapses and that a neuroligin mutation found in autism spectrum disorders impairs cell-surface transport but does not completely abolish synapse formation activity.

    Funded by: NIGMS NIH HHS: R37 GM 18360-29; NIMH NIH HHS: R37 MH 52804-08

    The Journal of biological chemistry 2005;280;23;22365-74

  • Solution structure of AF-6 PDZ domain and its interaction with the C-terminal peptides from Neurexin and Bcr.

    Zhou H, Xu Y, Yang Y, Huang A, Wu J and Shi Y

    Hefei National Laboratory for Physical Sciences at Microscale, School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.

    AF-6 is a key molecule essential for structure organization of cell-cell junction of polarized epithelia. It belongs to a novel cell-cell adhesion system. The AF-6 PDZ domain mediates interactions by binding to a specific amino acid sequence in target proteins. Here we report the solution structure of the AF-6 PDZ domain determined by NMR. Previously, the AF-6 PDZ domain was considered to be a class II PDZ domain. However we found that a unique hydrophilic amino acid, Gln70, at position alphaB1 makes the alphaB/betaB groove of the AF-6 PDZ domain significantly different from that of the canonical class II PDZ domain. The AF-6 PDZ domain does not have the second hydrophobic binding pocket, and the N-terminal end of alphaB is closer to betaB. Using BIACORE and NMR chemical shift perturbation experiments, we have studied the binding characteristics of the PDZ domain to the C-terminal peptide of Neurexin, KKNKDKEYYV, and that of Bcr, KRQSILFSTEV. The C-terminal peptide of Neurexin is a class II ligand, whereas that of Bcr is a class I ligand. The dissociation constants of these ligands were 4.08 x 10(-7) and 2.23 x 10(-6) m, respectively. Each of the four C-terminal positions in Neurexin and Bcr may contribute to the interaction. The three-dimensional models of the AF-6 PDZ-Neurexin C-terminal peptide complex and the AF-6 PDZ-Bcr C-terminal peptide complex were built up by molecular dynamics simulations. Unlike the canonical class II PDZ domain, Ala74 at alphaB5 rather than the residue at alphaB1 makes direct hydrophobic contact with the side chain of Tyr at the -2 position of the ligand.

    The Journal of biological chemistry 2005;280;14;13841-7

  • Generation and annotation of the DNA sequences of human chromosomes 2 and 4.

    Hillier LW, Graves TA, Fulton RS, Fulton LA, Pepin KH, Minx P, Wagner-McPherson C, Layman D, Wylie K, Sekhon M, Becker MC, Fewell GA, Delehaunty KD, Miner TL, Nash WE, Kremitzki C, Oddy L, Du H, Sun H, Bradshaw-Cordum H, Ali J, Carter J, Cordes M, Harris A, Isak A, van Brunt A, Nguyen C, Du F, Courtney L, Kalicki J, Ozersky P, Abbott S, Armstrong J, Belter EA, Caruso L, Cedroni M, Cotton M, Davidson T, Desai A, Elliott G, Erb T, Fronick C, Gaige T, Haakenson W, Haglund K, Holmes A, Harkins R, Kim K, Kruchowski SS, Strong CM, Grewal N, Goyea E, Hou S, Levy A, Martinka S, Mead K, McLellan MD, Meyer R, Randall-Maher J, Tomlinson C, Dauphin-Kohlberg S, Kozlowicz-Reilly A, Shah N, Swearengen-Shahid S, Snider J, Strong JT, Thompson J, Yoakum M, Leonard S, Pearman C, Trani L, Radionenko M, Waligorski JE, Wang C, Rock SM, Tin-Wollam AM, Maupin R, Latreille P, Wendl MC, Yang SP, Pohl C, Wallis JW, Spieth J, Bieri TA, Berkowicz N, Nelson JO, Osborne J, Ding L, Meyer R, Sabo A, Shotland Y, Sinha P, Wohldmann PE, Cook LL, Hickenbotham MT, Eldred J, Williams D, Jones TA, She X, Ciccarelli FD, Izaurralde E, Taylor J, Schmutz J, Myers RM, Cox DR, Huang X, McPherson JD, Mardis ER, Clifton SW, Warren WC, Chinwalla AT, Eddy SR, Marra MA, Ovcharenko I, Furey TS, Miller W, Eichler EE, Bork P, Suyama M, Torrents D, Waterston RH and Wilson RK

    Genome Sequencing Center, Washington University School of Medicine, Campus Box 8501, 4444 Forest Park Avenue, St. Louis, Missouri 63108, USA.

    Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington's disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions.

    Nature 2005;434;7034;724-31

  • Complete sequencing and characterization of 21,243 full-length human cDNAs.

    Ota T, Suzuki Y, Nishikawa T, Otsuki T, Sugiyama T, Irie R, Wakamatsu A, Hayashi K, Sato H, Nagai K, Kimura K, Makita H, Sekine M, Obayashi M, Nishi T, Shibahara T, Tanaka T, Ishii S, Yamamoto J, Saito K, Kawai Y, Isono Y, Nakamura Y, Nagahari K, Murakami K, Yasuda T, Iwayanagi T, Wagatsuma M, Shiratori A, Sudo H, Hosoiri T, Kaku Y, Kodaira H, Kondo H, Sugawara M, Takahashi M, Kanda K, Yokoi T, Furuya T, Kikkawa E, Omura Y, Abe K, Kamihara K, Katsuta N, Sato K, Tanikawa M, Yamazaki M, Ninomiya K, Ishibashi T, Yamashita H, Murakawa K, Fujimori K, Tanai H, Kimata M, Watanabe M, Hiraoka S, Chiba Y, Ishida S, Ono Y, Takiguchi S, Watanabe S, Yosida M, Hotuta T, Kusano J, Kanehori K, Takahashi-Fujii A, Hara H, Tanase TO, Nomura Y, Togiya S, Komai F, Hara R, Takeuchi K, Arita M, Imose N, Musashino K, Yuuki H, Oshima A, Sasaki N, Aotsuka S, Yoshikawa Y, Matsunawa H, Ichihara T, Shiohata N, Sano S, Moriya S, Momiyama H, Satoh N, Takami S, Terashima Y, Suzuki O, Nakagawa S, Senoh A, Mizoguchi H, Goto Y, Shimizu F, Wakebe H, Hishigaki H, Watanabe T, Sugiyama A, Takemoto M, Kawakami B, Yamazaki M, Watanabe K, Kumagai A, Itakura S, Fukuzumi Y, Fujimori Y, Komiyama M, Tashiro H, Tanigami A, Fujiwara T, Ono T, Yamada K, Fujii Y, Ozaki K, Hirao M, Ohmori Y, Kawabata A, Hikiji T, Kobatake N, Inagaki H, Ikema Y, Okamoto S, Okitani R, Kawakami T, Noguchi S, Itoh T, Shigeta K, Senba T, Matsumura K, Nakajima Y, Mizuno T, Morinaga M, Sasaki M, Togashi T, Oyama M, Hata H, Watanabe M, Komatsu T, Mizushima-Sugano J, Satoh T, Shirai Y, Takahashi Y, Nakagawa K, Okumura K, Nagase T, Nomura N, Kikuchi H, Masuho Y, Yamashita R, Nakai K, Yada T, Nakamura Y, Ohara O, Isogai T and Sugano S

    Helix Research Institute, 1532-3 Yana, Kisarazu, Chiba 292-0812, Japan.

    As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

    Nature genetics 2004;36;1;40-5

  • Characterization of the interaction of a recombinant soluble neuroligin-1 with neurexin-1beta.

    Comoletti D, Flynn R, Jennings LL, Chubykin A, Matsumura T, Hasegawa H, Südhof TC and Taylor P

    Department of Pharmacology, University of California, La Jolla, California 92093-0636, USA.

    Neuroligins, proteins of the alpha/beta-hydrolase fold family, are found as postsynaptic transmembrane proteins whose extracellular domain associates with presynaptic partners, proteins of the neurexin family. To characterize the molecular basis of neuroligin interaction with neurexin-beta, we expressed five soluble and exportable forms of neuroligin-1 from recombinant DNA sources, by truncating the protein before the transmembrane span near its carboxyl terminus. The extracellular domain of functional neuroligin-1 associates as a dimer when analyzed by sedimentation equilibrium. By surface plasmon resonance, we established that soluble neuroligins-1 bind neurexin-1beta, but the homologous alpha/beta-hydrolase fold protein, acetylcholinesterase, failed to associate with the neurexins. Neuroligin-1 has a unique N-linked glycosylation pattern in the neuroligin family, and glycosylation and its processing modify neuroligin activity. Incomplete processing of the protein and enzymatic removal of the oligosaccharides chain or the terminal sialic acids from neuroligin-1 enhance its activity, whereas deglycosylation of neurexin-1beta did not alter its association capacity. In particular, the N-linked glycosylation at position 303 appears to be a major determinant in modifying the association with neurexin-1beta. We show here that glycosylation processing of neuroligin, in addition to mRNA splicing and gene selection, contributes to the specificity of the neurexin-beta/neuroligin-1 association.

    Funded by: NIGMS NIH HHS: R37 GM-18360; NIMH NIH HHS: R37 MH52804

    The Journal of biological chemistry 2003;278;50;50497-505

  • Protein-protein interactions between large proteins: two-hybrid screening using a functionally classified library composed of long cDNAs.

    Nakayama M, Kikuno R and Ohara O

    Department of Human Gene Research, Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan. nmanabu@kazusa.or.jp

    Large proteins have multiple domains that are potentially capable of binding many kinds of partners. It is conceivable, therefore, that such proteins could function as an intricate framework of assembly protein complexes. To comprehensively study protein-protein interactions between large KIAA proteins, we have constructed a library composed of 1087 KIAA cDNA clones based on prior functional classifications done in silico. We were guided by two principles that raise the success rate for detecting interactions per tested combination: we avoided testing low-probability combinations, and reduced the number of potential false negatives that arise from the fact that large proteins cannot reliably be expressed in yeast. The latter was addressed by constructing a cDNA library comprised of random fragments encoding large proteins. Cytoplasmic domains of KIAA transmembrane proteins (>1000 amino acids) were used as bait for yeast two-hybrid screening. Our analyses reveal that several KIAA proteins bearing a transmembrane region have the capability of binding to other KIAA proteins containing domains (e.g., PDZ, SH3, rhoGEF, and spectrin) known to be localized to highly specialized submembranous sites, indicating that they participate in cellular junction formation, receptor or channel clustering, and intracellular signaling events. Our representative library should be a very useful resource for detecting previously unidentified interactions because it complements conventional expression libraries, which seldom contain large cDNAs.

    Genome research 2002;12;11;1773-84

  • Construction of expression-ready cDNA clones for KIAA genes: manual curation of 330 KIAA cDNA clones.

    Nakajima D, Okazaki N, Yamakawa H, Kikuno R, Ohara O and Nagase T

    Kazusa DNA Research Institute, Kisarazu, Chiba, Japan.

    We have accumulated information on protein-coding sequences of uncharacterized human genes, which are known as KIAA genes, through cDNA sequencing. For comprehensive functional analysis of the KIAA genes, it is necessary to prepare a set of cDNA clones which direct the synthesis of functional KIAA gene products. However, since the KIAA cDNAs were derived from long mRNAs (> 4 kb), it was not expected that all of them were full-length. Thus, as the first step toward preparing these clones, we evaluated the integrity of protein-coding sequences of KIAA cDNA clones through comparison with homologous protein entries in the public database. As a result, 1141 KIAA cDNAs had at least one homologous entry in the database, and 619 of them (54%) were found to be truncated at the 5' and/or 3' ends. In this study, 290 KIAA cDNA clones were tailored to be full-length or have considerably longer sequences than the original clones by isolating additional cDNA clones and/or connected parts of additional cDNAs or PCR products of the missing portion to the original cDNA clone. Consequently, 265, 8, and 17 predicted CDSs of KIAA cDNA clones were increased in the amino-, carboxy-, and both terminal sequences, respectively. In addition, 40 cDNA clones were modified to remove spurious interruption of protein-coding sequences. The total length of the resultant extensions at amino- and carboxy-terminals of KIAA gene products reached 97,000 and 7,216 amino acid residues, respectively, and various protein domains were found in these extended portions.

    DNA research : an international journal for rapid publication of reports on genes and genomes 2002;9;3;99-106

  • Structure and evolution of neurexin genes: insight into the mechanism of alternative splicing.

    Tabuchi K and Südhof TC

    Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA.

    Neurexins are neuron-specific vertebrate proteins with hundreds of differentially spliced isoforms that may function in synapse organization. We now show that Drosophila melanogaster and Caenorhabditis elegans express a single gene encoding only an alpha-neurexin, whereas humans and mice express three genes, each of which encodes alpha- and beta-neurexins transcribed from separate promoters. The neurexin genes are very large (up to 1.62 Mb), with the neurexin-3 gene occupying almost 2% of human chromosome 14. Although invertebrate and vertebrate neurexins exhibit a high degree of evolutionary conservation, only vertebrate neurexins are subject to extensive alternative splicing that uses mechanisms ranging from strings of mini-exons to multiple alternative splice donor and acceptor sites. Consistent with their proposed role in synapse specification, neurexins thus have evolved from relatively simple genes in invertebrates to diversified genes in vertebrates with multiple promoters and extensive alternative splicing.

    Funded by: NIMH NIH HHS: R01 MH 52804

    Genomics 2002;79;6;849-59

  • Analysis of the human neurexin genes: alternative splicing and the generation of protein diversity.

    Rowen L, Young J, Birditt B, Kaur A, Madan A, Philipps DL, Qin S, Minx P, Wilson RK, Hood L and Graveley BR

    Institute for Systems Biology, 1441 North 34th Street, Seattle, Washington 98103, USA.

    The neurexins are neuronal proteins that function as cell adhesion molecules during synaptogenesis and in intercellular signaling. Although mammalian genomes contain only three neurexin genes, thousands of neurexin isoforms may be expressed through the use of two alternative promoters and alternative splicing at up to five different positions in the pre-mRNA. To begin understanding how the expression of the neurexin genes is regulated, we have determined the complete nucleotide sequence of all three human neurexin genes: NRXN1, NRXN2, and NRXN3. Unexpectedly, two of these, NRXN1 ( approximately 1.1 Mb) and NRXN3 ( approximately 1.7 Mb), are among the largest known human genes. In addition, we have identified several conserved intronic sequence elements that may participate in the regulation of alternative splicing. The sequences of these genes provide insight into the mechanisms used to generate the diversity of neurexin protein isoforms and raise several interesting questions regarding the expression mechanism of large genes.

    Genomics 2002;79;4;587-97

  • The neural cell recognition molecule neurofascin interacts with syntenin-1 but not with syntenin-2, both of which reveal self-associating activity.

    Koroll M, Rathjen FG and Volkmer H

    Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, Berlin D-13092, Germany.

    Neurofascin belongs to the L1 subgroup of the immunoglobulin superfamily of cell adhesion molecules and is implicated in axonal growth and fasciculation. We used yeast two-hybrid screening to identify proteins that interact with neurofascin intracellularly and therefore might link it to trafficking, spatial targeting, or signaling pathways. Here, we demonstrate that rat syntenin-1, previously published as syntenin, mda-9, or TACIP18 in human, is a neurofascin-binding protein that exhibits a wide-spread tissue expression pattern with a relative maximum in brain. Syntenin-1 was found not to interact with other vertebrate members of the L1 subgroup such as L1 itself or NrCAM. We confirmed the specificity of the neurofascin-syntenin-1 interaction by ligand-overlay assay, surface plasmon resonance analysis, and colocalization of both proteins in heterologous cells. The COOH terminus of neurofascin was mapped to interact with the second PDZ domain of syntenin-1. Furthermore, we isolated syntenin-2 that may be expressed in two isoforms. Despite their high sequence similarity to syntenin-1, syntenin-2alpha, which interacts with neurexin I, and syntenin-2beta do not bind to neurofascin or several other transmembrane proteins that are binding partners of syntenin-1. Finally, we report that syntenin-1 and -2 both form homodimers and can interact with each other.

    The Journal of biological chemistry 2001;276;14;10646-54

  • Characterization of KIAA1427 protein as an atypical synaptotagmin (Syt XIII).

    Fukuda M and Mikoshiba K

    Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. mnfukuda@brain.riken.go.jp

    Synaptotagmin (Syt) belongs to a family of type-I membrane proteins and is a protein that consists of a short extracellular N-terminus, a single transmembrane domain, two C2 domains and a short C-terminus. Here, we cloned and characterized a mouse orthologue of human KIAA1427 protein as an atypical Syt (named Syt XIII). Subcellular fractionation and antibody-uptake experiments indicate that Syt XIII is indeed a type-I membrane protein, but, unlike other Syt isoforms, lacks an N-terminal extracellular domain. Syt XIII C2 domains show relatively little similarity to Syt I (less than 35% identity at the amino acid level), and lack key amino acids responsible for Ca2+ binding. Because of these substitutions, the Syt XIII C2 domains did not show Ca2+-dependent phospholipid-binding activity, and Syt XIII is thus classified as a Ca2+ -independent isoform. By contrast, the Syt XIII C-terminal domain is highly homologous with other Syt isoforms and can function as a common receptor for neurexin Ialpha in vitro. Since Syt XIII is expressed in various tissues outside the brain, Syt XIII may be involved in constitutive vesicle transport.

    The Biochemical journal 2001;354;Pt 2;249-57

  • Synaptotagmin-like protein 1-3: a novel family of C-terminal-type tandem C2 proteins.

    Fukuda M and Mikoshiba K

    Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. mnfukuda@brain.riken.go.jp

    Synaptotagmins (Syt), rabphilin-3A, and Doc2 belong to a family of carboxyl terminal type (C-type) tandem C2 proteins and are thought to be involved in vesicular trafficking. We have cloned and characterized a novel family of C-type tandem C2 proteins, designated Slp1-3 (synaptotagmin-like protein 1-3). The Slp1-3 C2 domains show high homology to granuphilin-a C2 domains, but the amino-terminal domain of Slp1-3 does not contain any known protein motifs or a transmembrane domain. A subcellular fractionation study indicated that Slp1-3 proteins are peripheral membrane proteins. Phospholipid binding experiments indicated that Slp3 is a Ca(2+)-dependent isoform, but Slp1 and Slp2 are Ca(2+)-independent isoforms, because only the Slp3 C2A domain showed Ca(2+)-dependent phospholipid binding activity. The C-terminus of Slp1-3 also bound neurexin Ialpha in vitro, in the same manner as Syt family proteins, which may be important for the membrane association of Slp1-3. In addition, Slp family proteins are differentially distributed in different mouse tissues and at different developmental stages.

    Biochemical and biophysical research communications 2001;281;5;1226-33

  • Mints as adaptors. Direct binding to neurexins and recruitment of munc18.

    Biederer T and Südhof TC

    Center for Basic Neuroscience, Department of Molecular Genetics, and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.

    Mint1 (X11/human Lin-10) and Mint2 are neuronal adaptor proteins that bind to Munc18-1 (n/rb-sec1), a protein essential for synaptic vesicle exocytosis. Mint1 has previously been characterized in a complex with CASK, another adaptor protein that in turn interacts with neurexins. Neurexins are neuron-specific cell surface proteins that act as receptors for the excitatory neurotoxin alpha-latrotoxin. Hence, one possible function for Mint1 is to mediate the recruitment of Munc18 to neurexins. In agreement with this hypothesis, we now show that the cytoplasmic tail of neurexins captures Munc18 via a multiprotein complex that involves Mint1. Furthermore, we demonstrate that both Mint1 and Mint2 can directly bind to neurexins in a PDZ domain-mediated interaction. Various Mint and/or CASK-containing complexes can be assembled on neurexins, and we demonstrate that Mint1 can bind to Munc18 and CASK simultaneously. Our data support a model whereby one of the functions of Mints is to localize the vesicle fusion protein Munc18 to those sites at the plasma membrane that are defined by neurexins, presumably in the vicinity of points of exocytosis.

    The Journal of biological chemistry 2000;275;51;39803-6

  • Neurexophilin binding to alpha-neurexins. A single LNS domain functions as an independently folding ligand-binding unit.

    Missler M, Hammer RE and Südhof TC

    Howard Hughes Medical Institute, University of Texas Southwestern Medical School, Dallas, Texas 75235, USA.

    alpha-Neurexins (Ialpha, IIalpha, and IIIalpha) are receptor-like proteins expressed in hundreds of isoforms on the neuronal cell surface. The extracellular domains of alpha-neurexins are composed of six LNS repeats, named after homologous sequences in the Laminin A G domain, Neurexins, and Sex hormone-binding globulin, with three interspersed epidermal growth factor-like domains. Purification of neurexin Ialpha revealed that it is tightly complexed to a secreted glycoprotein called neurexophilin 1. Neurexophilin 1 is a member of a family of at least four genes and resembles a neuropeptide, suggesting a function as an endogenous ligand for alpha-neurexins. We have now used recombinant proteins and knockout mice to investigate which isoforms and domains of different neurexins and neurexophilins interact with each other. We show that neurexophilins 1 and 3 but not 4 (neurexophilin 2 is not expressed in rodents) bind to a single individual LNS domain, the second overall LNS domain in all three alpha-neurexins. Although this domain is alternatively spliced, all splice variants bind, suggesting that alternative splicing does not regulate binding. Using homologous recombination to disrupt the neurexophilin 1 gene, we generated mutant mice that do not express detectable neurexophilin 1 mRNA. Mice lacking neurexophilin 1 are viable with no obvious morbidity or mortality. However, homozygous mutant mice exhibit male sterility, probably because homologous recombination resulted in the co-insertion into the neurexophilin gene of herpes simplex virus thymidine kinase, which is known to cause male sterility. In the neurexophilin 1 knockout mice, neurexin Ialpha is complexed with neurexophilin 3 but not neurexophilin 4, suggesting that neurexophilin 1 is redundant with neurexophilin 3 and that neurexophilins 1 and 3 but not 4 bind to neurexins. This hypothesis was confirmed using expression experiments. Our data reveal that the six LNS and three epidermal growth factor domains of neurexins are independently folding ligand-binding domains that may interact with distinct targets. The results support the notion that neurexophilins represent a family of extracellular signaling molecules that interact with multiple receptors including all three alpha-neurexins.

    Funded by: NIMH NIH HHS: MH52804

    The Journal of biological chemistry 1998;273;52;34716-23

  • CCG repeats in cDNAs from human brain.

    Kleiderlein JJ, Nisson PE, Jessee J, Li WB, Becker KG, Derby ML, Ross CA and Margolis RL

    Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.

    Expansion mutations of trinucleotide repeats and other units of unstable DNA have been proposed to account for at least some of the genetic susceptibility to a number of neuropsychiatric disorders, including bipolar affective disorder, schizophrenia, autism, and panic disorder. To generate additional candidate genes for these and other disorders, cDNA libraries from human brain were probed at high stringency for clones containing CCG, CGC, GCC, CGG, GCG, and GGC repeats (referred to collectively as CCG repeats). Some 18 cDNAs containing previously unpublished or uncharacterized repeats were characterized for chromosomal locus, repeat length polymorphism, and similarity to genes of known function. The cDNAs were also compared with the 37 human genes with eight or more consecutive CCG triplets in GenBank. The repeats were mapped to a number of loci, including 1p34, 2p11.2, 2q30-32, 3p21, 3p22, 4q35, 6q22, 7qter, 13p13, 17q24, 18p11, 19p13.3, 20q12, 20q13.3, and 22q12. Length polymorphism was detected in 50% of the repeats. The newly cloned cDNAs include a complete transcript of human neurexin-1B, a portion of BCNG-1 (a newly described brain-specific ion channel), a previously unreported polymorphic repeat located in the 5' UTR region of the guanine nucleotide-binding protein (G-protein) beta2 subunit, and a human version of the mouse proline-rich protein 7. This list of cDNAs should expedite the search for expansion mutations associated with diseases of the central nervous system.

    Funded by: NIMH NIH HHS: MH01275, MH50763

    Human genetics 1998;103;6;666-73

  • PDZ-domain-mediated interaction of the Eph-related receptor tyrosine kinase EphB3 and the ras-binding protein AF6 depends on the kinase activity of the receptor.

    Hock B, Böhme B, Karn T, Yamamoto T, Kaibuchi K, Holtrich U, Holland S, Pawson T, Rübsamen-Waigmann H and Strebhardt K

    Chemotherapeutisches Forschungsinstitut, Georg-Speyer-Haus, Paul-Ehrlich-Strasse 42-44, 60596 Frankfurt, Germany.

    Eph-related receptor tyrosine kinases (RTKs) have been implicated in intercellular communication during embryonic development. To elucidate their signal transduction pathways, we applied the yeast two-hybrid system. We could demonstrate that the carboxyl termini of the Eph-related RTKs EphA7, EphB2, EphB3, EphB5, and EphB6 interact with the PDZ domain of the ras-binding protein AF6. A mutational analysis revealed that six C-terminal residues of the receptors are involved in binding to the PDZ domain of AF6 in a sequence-specific fashion. Moreover, this PDZ domain also interacts with C-terminal sequences derived from other transmembrane receptors such as neurexins and the Notch ligand Jagged. In contrast to the association of EphB3 to the PDZ domain of AF6, the interaction with full-length AF6 clearly depends on the kinase activity of EphB3, suggesting a regulated mechanism for the PDZ-domain-mediated interaction. These data gave rise to the idea that the binding of AF6 to EphB3 occurs in a cooperative fashion because of synergistic effects involving different epitopes of both proteins. Moreover, in NIH 3T3 and NG108 cells endogenous AF6 is phosphorylated specifically by EphB3 and EphB2 in a ligand-dependent fashion. Our observations add the PDZ domain to the group of conserved protein modules such as Src-homology-2 (SH2) and phosphotyrosine-binding (PTB) domains that regulate signal transduction through their ability to mediate the interaction with RTKs.

    Proceedings of the National Academy of Sciences of the United States of America 1998;95;17;9779-84

  • Prediction of the coding sequences of unidentified human genes. IX. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro.

    Nagase T, Ishikawa K, Miyajima N, Tanaka A, Kotani H, Nomura N and Ohara O

    Kazusa DNA Research Institute, Kisarazu, Chiba, Japan.

    As an extension of a series of projects for sequencing human cDNA clones derived from relatively long transcripts, we herein report the entire sequences of 100 newly determined cDNA clones with the potential of coding for large proteins in vitro. The cDNA clones were isolated from size-fractionated human brain cDNA libraries with insert sizes between 4.5 and 8.3 kb. The sequencing of these clones revealed that the average size of the cDNA inserts and of their open reading frames was 5.3 kb and 2.8 kb (930 amino acid residues), respectively. Homology search against public databases indicated that the predicted coding sequences of 86 clones exhibited significant similarities to known genes; 51 of them (59%) were related to those for cell signaling/communication, nucleic acid management, and cell structure/motility. All the clones characterized in this study are accompanied by their expression profiles in 14 human tissues examined by reverse transcription-coupled polymerase chain reaction and the chromosomal mapping data.

    DNA research : an international journal for rapid publication of reports on genes and genomes 1998;5;1;31-9

  • Neurexins: three genes and 1001 products.

    Missler M and Südhof TC

    Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235, USA. mmissl@mednet.swmed.edu

    The human brain has approximately 10(12) neurons, three orders of magnitude more than there are basepairs in the human genome. Each neuron is connected to other neurons by thousands of synapses, creating a dense network of communicating neurons. Cell-recognition events between neurons at, and outside of synapses, are likely to guide the development and maintenance of the complex network formed by neurons. However, little is known about which proteins are important for neuronal cell recognition. Neurexins, a family of polymorphic cell-surface proteins, might mediate some of these cell recognition events. Thousands of neurexin isoforms are generated from three genes by usage of alternative promoters and alternative splicing. These isoforms are displayed on the neuronal cell surface, with different classes of neurons expressing distinct combinations of isoforms. Neurexins probably have a multitude of ligands, some of which interact only with subsets of neurexin isoforms. This review describes the properties of the neurexin protein family and their potential roles in neuronal cell adhesion and intercellular signaling.

    Funded by: NIMH NIH HHS: R01-MH52804

    Trends in genetics : TIG 1998;14;1;20-6

  • Binding properties of neuroligin 1 and neurexin 1beta reveal function as heterophilic cell adhesion molecules.

    Nguyen T and Südhof TC

    Department of Molecular Genetics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA.

    beta-Neurexins and neuroligins are plasma membrane proteins that are displayed on the neuronal cell surface. We have now investigated the interaction of neurexin 1beta with neuroligin 1 to evaluate their potential to function as heterophilic cell adhesion molecules. Using detergent-solubilized neuroligins and secreted neurexin 1beta-IgG fusion protein, we observed binding of these proteins to each other only in the presence of Ca2+ and in no other divalent cation tested. Only neurexin 1beta lacking an insert in splice site 4 bound neuroligins, whereas neurexin 1beta containing an insert was inactive. Half-maximal binding required 1-3 microM free Ca2+, which probably acts by binding to neuroligin 1 but not to neurexin 1beta. To determine if neurexin 1beta and neuroligin 1 can also interact with each other when present in a native membrane environment on the cell surface, we generated transfected cell lines expressing neuroligin 1 and neurexin 1beta. Upon mixing different cell populations, we found that cells aggregate only if cells expressing neurexin 1beta are mixed with cells expressing neuroligin 1. Aggregation was dependent on Ca2+ and was inhibited by the addition of soluble neurexin 1beta lacking an insert in splice site 4 but not by the addition of neurexin 1beta containing an insert in splice site 4. We conclude that neurexin 1beta and neuroligin 1 (and, by extension, other beta-neurexins and neuroligins) function as heterophilic cell adhesion molecules in a Ca2+-dependent reaction that is regulated by alternative splicing of beta-neurexins.

    Funded by: NIMH NIH HHS: R01-MH52804

    The Journal of biological chemistry 1997;272;41;26032-9

  • Mirror image motifs mediate the interaction of the COOH terminus of multiple synaptotagmins with the neurexins and calmodulin.

    Perin MS

    Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA.

    I have previously reported that the COOH-terminal 34 amino acids of synaptotagmin 1 are capable of interacting with the presynaptic proteins, the neurexins. Multiple synaptotagmins and a synaptotagmin-like protein, rabphilin 3A, are conserved in this domain, raising the possibility that many different synaptotagmins may interact with neurexins. Here 1 report that the COOH termini of synaptotagmins 1, 2, 4, 5, 6, 7, and 9 and rabphilin 3A are capable of interacting with neurexins. The COOH terminus of rabphilin 3A is still capable or substantial enrichment of neurexins from solubilized brain membranes even though only 11 of 33 residues are identical with the COOH terminus of synaptotagmin 1. Like the purification of neurexins on the COOH terminus of synaptotagmin 1, purification by the COOH terminus of rabphilin 3A is calcium-independent. The conservation between carboxyl termini of these proteins suggests symmetrical motifs are necessary for neurexin binding. These include the sequence Leu-X-His-Trp, followed by 13 amino acids, and the sequence Trp-His-X-Lcu. Deletion of the first motif or substitution of residues in the second of these motifs greatly reduces neurexin enrichment. Interestingly, these same COOH termini yield substantial calcium-dependent enrichment of calmodulin mediated by the first of these sequence motifs. This correlates with the binding of 125I-labeled calmodulin by recombinant pieces of synaptotagmn 1 containing the carboxyl terminus. These data suggest that multiple synaptotagmins may interact with neurexins to mediate docking or regulation of neurotransmitter release and that synaptotagmins may be calcium-regulated via interaction with calmodulin.

    Funded by: NINDS NIH HHS: R01 NS30541

    Biochemistry 1996;35;43;13808-16

  • Structure and evolution of neurexophilin.

    Petrenko AG, Ullrich B, Missler M, Krasnoperov V, Rosahl TW and Südhof TC

    Howard Hughes Medical Institute, University of Texas Southwestern Medical School, Dallas, Texas 75235, USA.

    Using affinity chromatography on immobilized alpha-latrotoxin, we have purified a novel 29 kDa protein, neurexophilin, in a complex with neurexin l alpha. Cloning revealed that rat and bovine neurexophilins are composed of N-terminal signal peptides, nonconserved N-terminal domains (20% identity over 80 residues), and highly homologous C-terminal sequences (85% identity over 169 residues). Analysis of genomic clones from mice identified two distinct neurexophilin genes, one of which is more homologous to rat neurexophilin and the other to bovine neurexophilin. The first neurexophilin gene is expressed abundantly in adult rat and mouse brain, whereas no mRNA corresponding to the second gene was detected in rodents despite its abundant expression in bovine brain, suggesting that rodents and cattle primarily express distinct neurexophilin genes. RNA blots and in situ hybridizations revealed that neurexophilin is expressed in adult rat brain at high levels only in a scattered subpopulation of neurons that probably represent inhibitory interneurons; by contrast, neurexins are expressed in all neurons. Neurexophilin contains a signal sequence and is N-glycosylated at multiple sites, suggesting that it is secreted and binds to the extracellular domain of neurexin l alpha. This hypothesis was confirmed by binding recombinant neurexophilin to the extracellular domains of neurexin l alpha. Together our data suggest that neurexophilin constitutes a secreted glycoprotein that is synthesized in a subclass of neurons and may be a ligand for neurexins.

    Funded by: NIMH NIH HHS: MH52804; NINDS NIH HHS: NS34937

    The Journal of neuroscience : the official journal of the Society for Neuroscience 1996;16;14;4360-9

  • CASK: a novel dlg/PSD95 homolog with an N-terminal calmodulin-dependent protein kinase domain identified by interaction with neurexins.

    Hata Y, Butz S and Südhof TC

    Department of Molecular Genetics, The University of Texa Southwestern Medical Center at Dallas, 75235, USA.

    Neurexins are neuronal cell surface proteins with hundreds of isoforms. In yeast two-hybrid screens for intracellular molecules interacting with different neurexins, we identified a single interacting protein called CASK. CASK is composed of an N-terminal Ca2+, calmodulin-dependent protein kinase sequence and a C-terminal region that is similar to the intercellular junction proteins dlg-A, PSD95/SAP90, SAP97, Z01, and Z02 and that contains DHR-, SH3-, and guanylate kinase domains. CASK is enriched in brain in synaptic plasma membranes but is also detectable at low levels in all tissues tested. The cytoplasmic domains of all three neurexins bind CASK in a salt-labile interaction. In neurexin I, this interaction is dependent on the C-terminal three residues. Thus, CASK is a membrane-associated protein that combines domains found in Ca2+ - activated protein kinases and in proteins specific for intercellular junctions, suggesting that it may be a signaling molecule operating at the plasma membrane, possibly in conjunction with neurexins.

    Funded by: NIMH NIH HHS: R01-MH52804

    The Journal of neuroscience : the official journal of the Society for Neuroscience 1996;16;8;2488-94

  • Structures, alternative splicing, and neurexin binding of multiple neuroligins.

    Ichtchenko K, Nguyen T and Südhof TC

    Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235, USA.

    Neuroligin 1 is a neuronal cell surface protein that binds to a subset of neurexins, polymorphic cell surface proteins that are also localized on neurons (Ichtchenko, K., Hata, Y., Nguyen, T., Ullrich, B., Missler, M., Moomaw, C., and Südhof, T. C. (1995) Cell 81, 435-443). We now describe two novel neuroligins called neuroligins 2 and 3 that are similar in structure and sequence to neuroligin 1. All neuroligins contain an N-terminal hydrophobic sequence with the characteristics of a cleaved signal peptide followed by a large esterase homology domain, a highly conserved single transmembrane region, and a short cytoplasmic domain. The three neuroligins are alternatively spliced at the same position and are expressed at high levels only in brain. Binding studies demonstrate that all three neuroligins bind to beta-neurexins both as native brain proteins and as recombinant proteins. Tight binding of the three neuroligins to beta-neurexins is observed only for beta-neurexins lacking an insert in splice site 4. Thus, neuroligins constitute a multigene family of brain-specific proteins with distinct isoforms that may have overlapping functions in mediating recognition processes between neurons.

    Funded by: NIMH NIH HHS: R01-MH52804

    The Journal of biological chemistry 1996;271;5;2676-82

  • Neurexins: synaptic cell surface proteins related to the alpha-latrotoxin receptor and laminin.

    Ushkaryov YA, Petrenko AG, Geppert M and Südhof TC

    Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas 75235.

    A family of highly polymorphic neuronal cell surface proteins, the neurexins, has been identified. At least two genes for neurexins exist. Each gene uses alternative promoters and multiple variably spliced exons to potentially generate more than a 100 different neurexin transcripts. The neurexins were discovered by the identification of one member of the family as the receptor for alpha-latrotoxin. This toxin is a component of the venom from black widow spiders; it binds to presynaptic nerve terminals and triggers massive neurotransmitter release. Neurexins contain single transmembrane regions and extracellular domains with repeated sequences similar to sequences in laminin A, slit, and agrin, proteins that have been implicated in axon guidance and synaptogenesis. An antibody to neurexin I showed highly concentrated immunoreactivity at the synapse. The polymorphic structure of the neurexins, their neural localization, and their sequence similarity to proteins associated with neurogenesis suggest a function as cell recognition molecules in the nerve terminal.

    Science (New York, N.Y.) 1992;257;5066;50-6

Gene lists (7)

Gene List Source Species Name Description Gene count
L00000009 G2C Homo sapiens Human PSD Human orthologues of mouse PSD adapted from Collins et al (2006) 1080
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000049 G2C Homo sapiens TAP-PSD-95-CORE TAP-PSD-95 pull-down core list (ortho) 120
L00000059 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-CONSENSUS Human cortex PSD consensus 748
L00000061 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-CONSENSUS Mouse cortex PSD consensus (ortho) 984
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
L00000071 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list (ortho) 1556
© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

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