G2Cdb::Gene report

Gene id
Gene symbol
Gnai1 (MGI)
Mus musculus
guanine nucleotide binding protein (G protein), alpha inhibiting 1
G00002400 (Homo sapiens)

Databases (9)

ENSMUSG00000057614 (Ensembl mouse gene)
14677 (Entrez Gene)
362 (G2Cdb plasticity & disease)
Gene Expression
MGI:95771 (Allen Brain Atlas)
g02689 (BGEM)
14677 (Genepaint)
139310 (OMIM)
Marker Symbol
MGI:95771 (MGI)
Protein Sequence
Q61018 (UniProt)

Synonyms (1)

  • Gialpha1

Alleles (1)

Literature (36)

Pubmed - other

  • Paradoxical attenuation of β2-AR function in airway smooth muscle by Gi-mediated counterregulation in transgenic mice overexpressing type 5 adenylyl cyclase.

    Wang WC, Schillinger RM, Malone MM and Liggett SB

    Dept. of Medicine, Univ. of Maryland School of Medicine, Baltimore, MD 21201, USA.

    The limiting component within the receptor-G protein-effector complex in airway smooth muscle (ASM) for β(2)-adrenergic receptor (β(2)-AR)-mediated relaxation is unknown. In cardiomyocytes, adenylyl cyclase (AC) is considered the "bottleneck" for β-AR signaling, and gene therapy trials are underway to increase inotropy by increasing cardiac AC expression. We hypothesized that increasing AC in ASM would increase relaxation from β-agonists, thereby providing a strategy for asthma therapy. Transgenic (TG) mice were generated with approximately two- to threefold overexpression of type 5 AC (AC5) in ASM. cAMP and airway relaxation in response to direct activation of AC by forskolin were increased in AC5-TG. Counter to our hypothesis, isoproterenol-mediated airway relaxation was significantly attenuated (∼50%) in AC5-TG, as was cAMP production, suggesting compensatory regulatory events limiting β(2)-AR signaling when AC expression is increased. In contrast, acetylcholine-mediated contraction was preserved. G(αi) expression and ERK1/2 activation were markedly increased in AC5-TG (5- and 8-fold, respectively), and β-AR expression was decreased by ∼40%. Other G proteins, G protein-coupled receptor kinases, and β-arrestins were unaffected. β-agonist-mediated airway relaxation of AC5-TG was normalized to that of nontransgenic mice by pertussis toxin, implicating β(2)-AR coupling to the increased G(i) as a mechanism of depressed agonist-promoted relaxation in these mice. The decrease in β(2)-AR may account for additional relaxation impairment, given that there is no enhancement over nontransgenic after pertussis toxin, despite AC5 overexpression. ERK1/2 inhibition had no effect on the phenotype. Thus perturbing the ratio of β(2)-AR to AC in ASM by increasing AC fails to improve (and actually decreases) β-agonist efficacy due to counterregulatory events.

    Funded by: NHLBI NIH HHS: HL045967, HL104119, R37 HL045967

    American journal of physiology. Lung cellular and molecular physiology 2011;300;3;L472-8

  • Activation of the regulator of G protein signaling 14-Gαi1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

    Vellano CP, Shu FJ, Ramineni S, Yates CK, Tall GG and Hepler JR

    Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, United States.

    RGS14 is a brain scaffolding protein that integrates G protein and MAP kinase signaling pathways. Like other RGS proteins, RGS14 is a GTPase activating protein (GAP) that terminates Gαi/o signaling. Unlike other RGS proteins, RGS14 also contains a G protein regulatory (also known as GoLoco) domain that binds Gαi1/3-GDP in cells and in vitro. Here we report that Ric-8A, a nonreceptor guanine nucleotide exchange factor (GEF), functionally interacts with the RGS14-Gαi1-GDP signaling complex to regulate its activation state. RGS14 and Ric-8A are recruited from the cytosol to the plasma membrane in the presence of coexpressed Gαi1 in cells, suggesting formation of a functional protein complex with Gαi1. Consistent with this idea, Ric-8A stimulates dissociation of the RGS14-Gαi1-GDP complex in cells and in vitro using purified proteins. Purified Ric-8A stimulates dissociation of the RGS14-Gαi1-GDP complex to form a stable Ric-8A-Gαi complex in the absence of GTP. In the presence of an activating nucleotide, Ric-8A interacts with the RGS14-Gαi1-GDP complex to stimulate both the steady-state GTPase activity of Gαi1 and binding of GTP to Gαi1. However, sufficiently high concentrations of RGS14 competitively reverse these stimulatory effects of Ric-8A on Gαi1 nucleotide binding and GTPase activity. This observation correlates with findings that show RGS14 and Ric-8A share an overlapping binding region within the last 11 amino acids of Gαi1. As further evidence that these proteins are functionally linked, native RGS14 and Ric-8A coexist within the same hippocampal neurons. These findings demonstrate that RGS14 is a newly appreciated integrator of unconventional Ric-8A and Gαi1 signaling.

    Funded by: NIGMS NIH HHS: GM088242, R01 GM088242, R01 GM088242-02, T32 GM008602; NINDS NIH HHS: P30 NS055077, P30NS055077, R01 NS037112, R01 NS037112-10A2, R01 NS037112-11, R01 NS049195, R01 NS049195-05, R01NS037112, R01NS049195, R56 NS037112, R56 NS037112-10A1

    Biochemistry 2011;50;5;752-62

  • CB2 cannabinoid receptor targets mitogenic Gi protein-cyclin D1 axis in osteoblasts.

    Ofek O, Attar-Namdar M, Kram V, Dvir-Ginzberg M, Mechoulam R, Zimmer A, Frenkel B, Shohami E and Bab I

    Bone Laboratory, Hebrew University of Jerusalem, Jerusalem, Israel.

    CB2 is a Gi protein-coupled receptor activated by endo- and phytocannabinoids, thus inhibiting stimulated adenylyl cyclase activity. CB2 is expressed in bone cells and Cb2 null mice show a marked age-related bone loss. CB2-specific agonists both attenuate and rescue ovariectomy-induced bone loss. Activation of CB2 stimulates osteoblast proliferation and bone marrow derived colony-forming units osteoblastic. Here we show that selective and nonselective CB2 agonists are mitogenic in MC3T3 E1 and newborn mouse calvarial osteoblastic cultures. The CB2 mitogenic signaling depends critically on the stimulation of Erk1/2 phosphorylation and de novo synthesis of MAP kinase-activated protein kinase 2 (Mapkapk2) mRNA and protein. Further downstream, CB2 activation enhances CREB transcriptional activity and cyclin D1 mRNA expression. The CB2-induced stimulation of CREB and cyclin D1 is inhibitable by pertussis toxin, the MEK-Erk1/2 inhibitors PD098059 and U0126, and Mapkapk2 siRNA. These data demonstrate that in osteoblasts CB2 targets a Gi protein-cyclin D1 mitogenic axis. Erk1/2 phosphorylation and Mapkapk2 protein synthesis are critical intermediates in this axis.

    Funded by: NIAMS NIH HHS: AR047052, R01 AR047052; PHS HHS: 9789

    Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2011;26;2;308-16

  • Augmented glucose-induced insulin release in mice lacking G(o2), but not G(o1) or G(i) proteins.

    Wang Y, Park S, Bajpayee NS, Nagaoka Y, Boulay G, Birnbaumer L and Jiang M

    Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.

    Insulin secretion by pancreatic β cells is a complex and highly regulated process. Disruption of this process can lead to diabetes mellitus. One of the various pathways involved in the regulation of insulin secretion is the activation of heterotrimeric G proteins. Bordetella pertussis toxin (PTX) promotes insulin secretion, suggesting the involvement of one or more of three G(i) and/or two G(o) proteins as suppressors of insulin secretion from β cells. However, neither the mechanism of this inhibitory modulation of insulin secretion nor the identity of the G(i/o) proteins involved has been elucidated. Here we show that one of the two splice variants of G(o), G(o2), is a key player in the control of glucose-induced insulin secretion by β cells. Mice lacking G(o2)α, but not those lacking α subunits of either G(o1) or any G(i) proteins, handle glucose loads more efficiently than wild-type (WT) mice, and do so by increased glucose-induced insulin secretion. We thus provide unique genetic evidence that the G(o2) protein is a transducer in an inhibitory pathway that prevents damaging oversecretion of insulin.

    Funded by: Intramural NIH HHS; NIDDK NIH HHS: DK 069771, DK19319, R01 DK069771; NIEHS NIH HHS: Z01 ES101643

    Proceedings of the National Academy of Sciences of the United States of America 2011;108;4;1693-8

  • A high-resolution anatomical atlas of the transcriptome in the mouse embryo.

    Diez-Roux G, Banfi S, Sultan M, Geffers L, Anand S, Rozado D, Magen A, Canidio E, Pagani M, Peluso I, Lin-Marq N, Koch M, Bilio M, Cantiello I, Verde R, De Masi C, Bianchi SA, Cicchini J, Perroud E, Mehmeti S, Dagand E, Schrinner S, Nürnberger A, Schmidt K, Metz K, Zwingmann C, Brieske N, Springer C, Hernandez AM, Herzog S, Grabbe F, Sieverding C, Fischer B, Schrader K, Brockmeyer M, Dettmer S, Helbig C, Alunni V, Battaini MA, Mura C, Henrichsen CN, Garcia-Lopez R, Echevarria D, Puelles E, Garcia-Calero E, Kruse S, Uhr M, Kauck C, Feng G, Milyaev N, Ong CK, Kumar L, Lam M, Semple CA, Gyenesei A, Mundlos S, Radelof U, Lehrach H, Sarmientos P, Reymond A, Davidson DR, Dollé P, Antonarakis SE, Yaspo ML, Martinez S, Baldock RA, Eichele G and Ballabio A

    Telethon Institute of Genetics and Medicine, Naples, Italy.

    Ascertaining when and where genes are expressed is of crucial importance to understanding or predicting the physiological role of genes and proteins and how they interact to form the complex networks that underlie organ development and function. It is, therefore, crucial to determine on a genome-wide level, the spatio-temporal gene expression profiles at cellular resolution. This information is provided by colorimetric RNA in situ hybridization that can elucidate expression of genes in their native context and does so at cellular resolution. We generated what is to our knowledge the first genome-wide transcriptome atlas by RNA in situ hybridization of an entire mammalian organism, the developing mouse at embryonic day 14.5. This digital transcriptome atlas, the Eurexpress atlas (http://www.eurexpress.org), consists of a searchable database of annotated images that can be interactively viewed. We generated anatomy-based expression profiles for over 18,000 coding genes and over 400 microRNAs. We identified 1,002 tissue-specific genes that are a source of novel tissue-specific markers for 37 different anatomical structures. The quality and the resolution of the data revealed novel molecular domains for several developing structures, such as the telencephalon, a novel organization for the hypothalamus, and insight on the Wnt network involved in renal epithelial differentiation during kidney development. The digital transcriptome atlas is a powerful resource to determine co-expression of genes, to identify cell populations and lineages, and to identify functional associations between genes relevant to development and disease.

    Funded by: Medical Research Council: MC_U127527203; Telethon: TGM11S03

    PLoS biology 2011;9;1;e1000582

  • A G(i) -independent mechanism mediating Akt phosphorylation in platelets.

    Xiang B, Zhang G, Liu J, Morris AJ, Smyth SS, Gartner TK and Li Z

    Division of Cardiovascular Medicine, The Gill Heart Institute, University of Kentucky, Lexington, KY, USA.

    Background: The serine-threonine kinase Akt plays an important role in regulating platelet activation. Stimulation of platelets with various agonists results in Akt activation as indicated by Akt phosphorylation. However, the mechanisms of Akt phosphorylation in platelets are not completely understood.

    We used P2Y₁ knockout mice to address the role of P2Y₁₂ in Akt phosphorylation in response to thrombin receptors in platelets.

    Results: Thrombin or the PAR4 thrombin receptor peptide AYPGKF at high concentrations stimulated substantial phosphorylation of Akt residues Thr³⁰⁸ and Ser⁴⁷³ in P2Y₁₂-deficient platelets. AYPGKF-induced Akt phosphorylation is enhanced by expression of recombinant human PAR4 cDNA in Chinese hamster ovary (CHO) cells. P2Y₁₂ -independent Akt phosphorylation was not inhibited by integrin inhibitor peptide RGDS or integrin β₃ deficiency. Akt phosphorylation induced by thrombin or AYPGKF in P2Y₁₂-deficient platelets was inhibited by the calcium chelator dimethyl-BAPTA, the Src family kinase inhibitor PP2, and PI3K inhibitors, respectively.

    Conclusions: Our results reveal a novel P2Y₁₂-independent signaling pathway mediating Akt phosphorylation in response to thrombin receptors.

    Funded by: NCRR NIH HHS: P20 RR021954, P20 RR021954-03, P20RR021954-01A1, S10 RR024598

    Journal of thrombosis and haemostasis : JTH 2010;8;9;2032-41

  • CKbeta8/CCL23 and its isoform CKbeta8-1 induce up-regulation of cyclins via the G(i)/G(o) protein/PLC/PKCdelta/ERK leading to cell-cycle progression.

    Kim J, Kim YS and Ko J

    Korea University, Seoul, South Korea.

    CKbeta8/CCL23 is a CC chemokine and alternative splicing of the CKbeta8 gene produces two mRNAs that encode CKbeta8 and its isoform CKbeta8-1. Chemokines play a critical role in leukocyte trafficking and development of inflammation and chemokines are also known to be involved in cell proliferation. To investigate participation of CKbeta8 and CKbeta8-1 in cell proliferation, we examined the effects of CKbeta8 and CKbeta8-1 in the cell cycle. Both CKbeta8 and CKbeta8-1 induced cell-cycle progression. We next investigated whether MAPKs are involved in CKbeta8- and CKbeta8-1-induced cell proliferation. CKbeta8- and CKbeta8-1-stimulated cells showed phosphorylation of ERK1/2 and an inhibitor study indicated that CKbeta8- and CKbeta8-1-induced activation of ERK1/2 is mediated by the G(i)/G(o) protein, PLC, and PKCdelta. CKbeta8 and CKbeta8-1 regulated expression of the cell cycle regulators cyclin D(3) and cyclin B(1,) and the immediate early response gene products c-Myc and Egr-1. These results indicate that both CKbeta8 and CKbeta8-1 are involved in cell proliferation by modulating the cell cycle regulators.

    Cytokine 2010;50;1;42-9

  • Agonist dose-dependent phosphorylation by protein kinase A and G protein-coupled receptor kinase regulates beta2 adrenoceptor coupling to G(i) proteins in cardiomyocytes.

    Liu R, Ramani B, Soto D, De Arcangelis V and Xiang Y

    Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA.

    Adrenoceptors receptors (ARs) play a pivotal role in regulating cardiovascular response to catecholamines during stress. beta(2)ARs, prototypical G protein-coupled receptors (GPCRs), expressed in animal hearts, display dual coupling to both G(s) and G(i) proteins to control the adenylyl cyclase-cAMP dependent protein kinase A (PKA) pathway to regulate contraction responses. Here, we showed that the beta(2)AR coupling to G(i) proteins was agonist dose-dependent and occurred only at high concentrations in mouse cardiac myocytes. Both the beta(2)AR-induced PKA activity, measured by fluorescence resonance energy transfer (FRET) imaging, and the increase in myocyte contraction rate displayed sensitivity to the G(i) inhibitor pertussis toxin (PTX). Further studies revealed that activated beta(2)ARs underwent PKA phosphorylation at a broad range of agonist concentrations. Disruption of the PKA phosphorylation sites on the beta(2)AR blocked receptor/G(i) coupling. However, a sufficient beta(2)AR/G(i) coupling was also dependent on the G protein-coupled receptor kinase (GRK)-mediated phosphorylation of the receptors, which only occurred at high concentrations of agonist (> or = 100 nm). Disruption of the GRK phosphorylation sites on the beta(2)AR blocked receptor internalization and coupling to G(i) proteins, probably by preventing the receptor's transportation to access G(i) proteins. Furthermore, neither PKA nor GRK site mutated receptors displayed sensitivity to the G(i)-specific inhibitor, G(i)CT. Together, our studies revealed distinct roles of PKA and GRK phosphorylation of the beta(2)AR for agonist dose-dependent coupling to G(i) proteins in cardiac myocytes, which may protect cells from overstimulation under high concentrations of catecholamines.

    Funded by: NHLBI NIH HHS: HL082846, R01 HL082846, R01 HL082846-05

    The Journal of biological chemistry 2009;284;47;32279-87

  • The role of inhibitory heterotrimeric G proteins in the control of in vivo heart rate dynamics.

    Zuberi Z, Birnbaumer L and Tinker A

    British Heart Foundation, Laboratories and Department of Medicine, University College London, 5 University St., London, WC1E 6JJ, UK.

    Multiple isoforms of inhibitory Galpha-subunits (Galphai1,2,3, as well as Galphao) are present within the heart, and their role in modulating pacemaker function remains unresolved. Do inhibitory Galpha-subunits selectively modulate parasympathetic heart rate responses? Published findings using a variety of experimental approaches have implicated roles for Galphai2, Galphai3, and Galphao in parasympathetic signal transduction. We have compared in vivo different groups of mice with global genetic deletion of Gialpha1/Galphai3, Galphai2, and Galphao against littermate controls using implanted ECG telemetry. Significant resting tachycardia was observed in Galphai2(-/-) and Galphao(-/-) mice compared with control and Galphai1(-/-)/Galphai3(-/-) mice (P < 0.05). Loss of diurnal heart rate variation was seen exclusively in Galphao(-/-) mice. Using heart rate variability (HRV) analysis, compared with littermate controls (4.02 ms2 +/- 1.17; n = 6, Galphai2(-/-)) mice have a selective attenuation of high-frequency (HF) power (0.73 ms2 +/- 0.31; n = 5, P < 0.05). Galphai1(-/-)/Galphai3(-/-) and Galphao(-/-) cohorts have nonsignificant changes in HF power. Galphao(-/-) mice have a different basal HRV signature. The observed HRV phenotype in Galphai2(-/-) mice was qualitatively similar to atropine (1 mg/kg)-treated controls [and mice treated with the GIRK channel blocker tertiapinQ (0.05 mg/kg)]. Maximal cardioinhibitory response to the M(2)-receptor agonist carbachol (0.5 mg/kg) compared with basal heart rate was attenuated in Galphai2(-/-) mice (0.08 +/- 0.04; n = 6) compared to control (0.27 +/- 0.04; n = 7 P < 0.05). Our data suggest a selective defect of parasympathetic heart rate modulation in mice with Galphai2 deletion. Mice with Galphao deletion also have a defect in short-term heart rate dynamics, but this is qualitatively different to the effects of atropine, tertiapinQ, and Galphai2 deletion. In contrast, Galphai1 and Galphai3 do not appear to be essential for parasympathetic responses in vivo.

    Funded by: British Heart Foundation; Intramural NIH HHS; Medical Research Council: G0500441; Wellcome Trust

    American journal of physiology. Regulatory, integrative and comparative physiology 2008;295;6;R1822-30

  • Activation of Galpha (i) and subsequent uncoupling of receptor-Galpha(i) signaling by Pasteurella multocida toxin.

    Orth JH, Fester I, Preuss I, Agnoletto L, Wilson BA and Aktories K

    Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany.

    Bacterial protein toxins are powerful tools for elucidating signaling mechanisms in eukaryotic cells. A number of bacterial protein toxins, e.g. cholera toxin, pertussis toxin (PTx), or Pasteurella multocida toxin (PMT), target heterotrimeric G proteins and have been used to stimulate or block specific signaling pathways or to demonstrate the contribution of their target proteins in cellular effects. PMT is a major virulence factor of P. multocida causing pasteurellosis in man and animals and is responsible for atrophic rhinitis in pigs. PMT modulates various signaling pathways, including phospholipase Cbeta and RhoA, by acting on the heterotrimeric G proteins Galpha(q) and Galpha(12/13), respectively. Here we report that PMT is a powerful activator of G(i) protein. We show that PMT decreases basal isoproterenol and forskolin-stimulated cAMP accumulation in intact Swiss 3T3 cells, inhibits adenylyl cyclase activity in cell membrane preparations, and enhances the inhibition of cAMP accumulation caused by lysophosphatidic acid via endothelial differentiation gene receptors. PMT-mediated inhibition of cAMP production is independent of toxin activation of Galpha(q) and/or Galpha(12/13). Although the effects of PMT are not inhibited by PTx, PMT blocks PTx-catalyzed ADP-ribosylation of G(i). PMT also inhibits steady-state GTPase activity and GTP binding of G(i) in Swiss 3T3 cell membranes stimulated by lysophosphatidic acid. The data indicate that PMT is a novel activator of G(i), modulating its GTPase activity and converting it into a PTx-insensitive state.

    Funded by: NIAID NIH HHS: R01 AI038396

    The Journal of biological chemistry 2008;283;34;23288-94

  • Differential regulation of lipopolysaccharide and Gram-positive bacteria induced cytokine and chemokine production in macrophages by Galpha(i) proteins.

    Fan H, Williams DL, Zingarelli B, Breuel KF, Teti G, Tempel GE, Spicher K, Boulay G, Birnbaumer L, Halushka PV and Cook JA

    Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.

    Heterotrimeric G(i) proteins play a role in signalling activated by lipopolysaccharide (LPS), Staphylococcus aureus (SA) and group B streptococci (GBS), leading to production of inflammatory mediators. We hypothesized that genetic deletion of G(i) proteins would alter cytokine and chemokine production induced by LPS, SA and GBS stimulation. LPS-induced, heat-killed SA-induced and heat-killed GBS-induced cytokine and chemokine production in peritoneal macrophages from wild-type (WT), Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice were investigated. LPS induced production of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10 and interferon-gamma-inducible protein-10 (IP-10); SA induced TNF-alpha, and IL-1beta production; and GBS induced TNF-alpha, IL-6, IL-1beta, macrophage inflammatory protein-1alpha (MIP-1alpha) and keratinocyte chemoattract (KC) production were all decreased (P < 0.05) in Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice compared with WT mice. In contrast to the role of G(i) proteins as a positive regulator of mediators, LPS-induced production of MIP-1alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) were increased in macrophages from Galpha(i1/3) (-/-) mice, and SA-induced MIP-1alpha production was increased in both groups of Galpha(i) protein-depleted mice. LPS-induced production of KC and IL-1beta, SA-induced production of GM-CSF, KC and IP-10, and GBS-induced production of IL-10, GM-CSF and IP-10 were unchanged in macrophages from Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice compared with WT mice. These data suggest that G(i2) and G(i1/3) proteins are both involved and differentially regulate murine inflammatory cytokine and chemokine production in response to both LPS and Gram-positive microbial stimuli.

    Funded by: Intramural NIH HHS; NIDDK NIH HHS: DK19318; NIGMS NIH HHS: GM27673, GM53522, GM67202, R01 GM027673, R01 GM053522, R01 GM067202

    Immunology 2007;122;1;116-23

  • Expression of trace amine-associated receptors in the Grueneberg ganglion.

    Fleischer J, Schwarzenbacher K and Breer H

    University of Hohenheim, Institute of Physiology, Garbenstrasse 30, D-70599 Stuttgart, Germany.

    The Grueneberg ganglion (GG) in the vestibule of the anterior nasal cavity is considered as an olfactory subcompartment based on expression of the olfactory marker protein (OMP) and axonal projection to the olfactory bulb. Searching for olfactory receptors present in the GG, it has been observed recently that V2r83, a member of the V2R class of olfactory receptors, is expressed in numerous cells in the GG of mice. However, no other olfactory receptors have been found to be present in a considerable number of GG neurons so far. Here, we report that GG neurons express trace amine-associated receptors (TAARs) that have most recently been described as a novel class of olfactory receptors. It was observed that several TAAR subtypes are expressed by defined subpopulations of GG neurons distinct from the V2r83-positive cells. Analyzing the time course of TAAR expression during pre- and postnatal development revealed that TAARs are expressed by a substantial portion of GG neurons in late embryonic and neonatal stages, whereas in juveniles and adults, the number of TAAR-positive cells in the GG was significantly decreased.

    Chemical senses 2007;32;6;623-31

  • Detection of novel skeletogenesis target genes by comprehensive analysis of a Runx2(-/-) mouse model.

    Hecht J, Seitz V, Urban M, Wagner F, Robinson PN, Stiege A, Dieterich C, Kornak U, Wilkening U, Brieske N, Zwingman C, Kidess A, Stricker S and Mundlos S

    Max Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin,Germany.

    Runx2 is an essential factor for skeletogenesis and heterozygous loss causes cleidocranial dysplasia in humans and a corresponding phenotype in the mouse. Homozygous Runx2-deficient mice lack hypertrophic cartilage and bone. We compared the expression profiles of E14.5 wildtype and Runx2(-/-) murine embryonal humeri to identify new transcripts potentially involved in cartilage and bone development. Seventy-one differentially expressed genes were identified by two independent oligonucleotide-microarray hybridizations and quantitative RT-PCR experiments. Gene Ontology analysis demonstrated an enrichment of the differentially regulated genes in annotations to terms such as extracellular, skeletal development, and ossification. In situ hybridization on E15.5 limb sections was performed for all 71 differentially regulated genes. For 54 genes conclusive in situ hybridization results were obtained and all of them showed skeletal expression. Co-expression with Runx2 was demonstrated for 44 genes. While 41 of the 71 differentially expressed genes have a known role in bone and cartilage, we identified 21 known genes that have not yet been implicated in skeletal development and 9 entirely new transcripts. Expression in the developing skeleton was demonstrated for 21 of these genes.

    Gene expression patterns : GEP 2007;7;1-2;102-12

  • Lysophospholipids control integrin-dependent adhesion in splenic B cells through G(i) and G(12)/G(13) family G-proteins but not through G(q)/G(11).

    Rieken S, Herroeder S, Sassmann A, Wallenwein B, Moers A, Offermanns S and Wettschureck N

    Institute of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, Heidelberg, Germany.

    Integrin-mediated adhesion is a crucial step in lymphocyte extravasation and homing. We show here that not only the chemokines CXCL12 and CXCL13 but also the lysophospholipids sphingosine 1-phosphate (S1P) and lysophosphatidic acid (LPA) enhance adhesion of murine follicular and marginal zone B cells to ICAM-1 in vitro. This process involves clustering of integrin LFA-1 and is blocked by pertussis toxin, suggesting that G(i) family G-proteins are involved. In addition, lysophospholipid-induced adhesion on ICAM-1 depends on Rho and Rhokinase, indicative of an involvement of G(12)/G(13), possibly also G(q)/G(11) family G-proteins. We used G(12)/G(13)- or G(q)/G(11)-deficient B cells to study the role of these G-protein families in lysophospholipid-induced adhesion and found that the pro-adhesive effects of LPA and S1P are completely abrogated in G(12)/G(13)-deficient marginal zone B cells, reduced in G(12)/G(13)-deficient follicular B cells, and normal in G(q)/G(11)-deficient B cells. We also show that loss of lysophospholipid-induced adhesion results in disinhibition of migration in response to the follicular chemokine CXCL13, which might contribute to the abnormal localization of splenic B cell populations observed in B cell-specific G(12)/G(13)-deficient mice in vivo. Taken together, this study shows that lysophospholipids regulate integrin-mediated adhesion of splenic B cells to ICAM-1 through G(i) and G(12)/G(13) family G-proteins but not through G(q)/G(11).

    The Journal of biological chemistry 2006;281;48;36985-92

  • Differential regulation of lipopolysaccharide and Gram-positive bacteria induced cytokine and chemokine production in splenocytes by Galphai proteins.

    Fan H, Williams DL, Zingarelli B, Breuel KF, Teti G, Tempel GE, Spicher K, Boulay G, Birnbaumer L, Halushka PV and Cook JA

    Department of Neuroscience, 173 Ashley Ave., BSB Room 403, Charleston, SC 29425, USA.

    Heterotrimeric Gi proteins play a role in lipopolysaccharide (LPS) and Staphylococcus aureus (SA) activated signaling leading to inflammatory mediator production. We hypothesized that genetic deletion of Gi proteins would alter cytokine and chemokine production induced by LPS and SA. LPS- and heat killed SA-induced cytokine and chemokine production in splenocytes from wild type (WT), Galpha(i2) (-/-) or Galpha(i1/3) (-/-) mice were investigated. LPS- or SA-induced production of TNFalpha, IL-6, IFNgamma, IL-12, IL-17, GM-CSF, MIP-1alpha, MCP-1, MIG and IP-10 were significantly increased (1.2 to 33 fold, p<0.05) in splenocytes harvested from Galpha(i2)(-/-) mice compared with WT mice. The effect of Galpha(i) protein depletion was remarkably isoform specific. In splenocytes from Galpha(i1/3) (-/-) mice relative to WT mice, SA-induced IL-6, IFNgamma, GM-CSF, and IP-10 levels were decreased (59% to 86%, p<0.05), whereas other LPS- or SA-stimulated cytokines and chemokines were not different relative to WT mice. LPS- and SA-induced production of KC were unchanged in both groups of the genetic deficient mice. Splenocytes from both Galpha(i2) (-/-) and Galpha(i1/3) (-/-) mice did not exhibit changes in TLR2 and TLR4 expression. Also analysis of splenic cellular composition by flow cytometry demonstrated an increase in splenic macrophages and reduced CD4 T cells in both Galpha(i2) (-/-) and Galpha(i1/3) (-/-) mice relative to WT mice. The disparate response of splenocytes from the Galpha(i2) (-/-) relative to Galpha(i1/3) (-/-) mice therefore cannot be attributed to major differences in spleen cellular composition. These data demonstrate that G(i2) and G(i1/3) proteins are both involved and differentially regulate splenocyte inflammatory cytokine and chemokine production in a highly Gi isoform specific manner in response to LPS and Gram-positive microbial stimuli.

    Funded by: Intramural NIH HHS; NIDDK NIH HHS: DK19318; NIGMS NIH HHS: GM27673, GM53522, GM67202, R01 GM027673

    Biochimica et biophysica acta 2006;1763;10;1051-8

  • Olfactory receptors and signalling elements in the Grueneberg ganglion.

    Fleischer J, Schwarzenbacher K, Besser S, Hass N and Breer H

    University of Hohenheim, Institute of Physiology, Stuttgart, Germany. joergf@uni-hohenheim.de

    The Grueneberg ganglion (GG) is a cluster of neurones present in the vestibule of the anterior nasal cavity. Although its function is still elusive, recent studies have shown that cells of the GG transcribe the gene encoding the olfactory marker protein (OMP) and project their axons to glomeruli of the olfactory bulb, suggesting that they may have a chemosensory function. Chemosensory responsiveness of olfactory neurones in the main olfactory epithelium (MOE) and the vomeronasal organ (VNO) is based on the expression of either odorant receptors or vomeronasal putative pheromone receptors. To scrutinize its presumptive olfactory nature, the GG was assessed for receptor expression by extensive RT-PCR analyses, leading to the identification of a distinct vomeronasal receptor which was expressed in the majority of OMP-positive GG neurones. Along with this receptor, these cells expressed the G proteins Go and Gi, both of which are also present in sensory neurones of the vomeronasal organ. Odorant receptors were expressed by very few cells during prenatal and perinatal stages; a similar number of cells expressed adenylyl cyclase type III and G(olf/s), characteristic signalling elements of the main olfactory system. The findings of the study support the notion that the GG is in fact a subunit of the complex olfactory system, comprising cells with either a VNO-like or a MOE-like phenotype. Moreover, expression of a vomeronasal receptor indicates that the GG might serve to detect pheromones.

    Journal of neurochemistry 2006;98;2;543-54

  • BGEM: an in situ hybridization database of gene expression in the embryonic and adult mouse nervous system.

    Magdaleno S, Jensen P, Brumwell CL, Seal A, Lehman K, Asbury A, Cheung T, Cornelius T, Batten DM, Eden C, Norland SM, Rice DS, Dosooye N, Shakya S, Mehta P and Curran T

    Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, Tennessee, United States.

    Funded by: NINDS NIH HHS: 5R37NS036558, N01-NS-0-2331, R37 NS036558

    PLoS biology 2006;4;4;e86

  • Lipopolysaccharide- and gram-positive bacteria-induced cellular inflammatory responses: role of heterotrimeric Galpha(i) proteins.

    Fan H, Zingarelli B, Peck OM, Teti G, Tempel GE, Halushka PV, Spicher K, Boulay G, Birnbaumer L and Cook JA

    Department of Physiology and Neuroscience, Medical University of South Carolina, 173 Ashley Ave., BSB Rm. 403, Charleston, SC 29425, USA.

    Heterotrimeric G(i) proteins may play a role in lipopolysaccharide (LPS)-activated signaling through Toll-like receptor 4 (TLR4), leading to inflammatory mediator production. Although LPS is a TLR4 ligand, the gram-positive bacterium Staphylococcus aureus (SA) is a TLR2 ligand, and group B streptococci (GBS) are neither TLR2 nor TLR4 ligands but are MyD88 dependent. We hypothesized that genetic deletion of G(i) proteins would alter mediator production induced by LPS and gram-positive bacterial stimulation. We examined genetic deletion of Galpha(i2) or Galpha(i1/3) protein in Galpha(i2)-knockout (Galpha(i2)-/-) or Galpha(i1/3)-knockout (Galpha(i1/3)-/-) mice. LPS-, heat-killed SA-, or GBS-induced mediator production in splenocytes or peritoneal macrophages (MPhi) was investigated. There were significant increases in LPS-, SA-, and GBS-induced production of TNF-alpha and IFN-gamma in splenocytes from Galpha(i2)-/- mice compared with wild-type (WT) mice. Also, LPS-induced TNF-alpha was increased in splenocytes from Galpha(i1/3)-/- mice. In contrast to splenocytes, LPS-, SA-, and GBS-induced TNF-alpha, IL-10, and thromboxane B(2) (TxB(2)) production was decreased in MPhi harvested from Galpha(i2)-/- mice. Also, LPS-induced production of IL-10 and TxB(2) was decreased in MPhi from Galpha(i1/3)-/- mice. In subsequent in vivo studies, TNF-alpha levels after LPS challenge were significantly greater in Galpha(i2)-/- mice than in WT mice. Also, myeloperoxidase activity, a marker of tissue neutrophil infiltration, was significantly increased in the gut and lung of LPS-treated Galpha(i2)-/- mice compared with WT mice. These data suggest that G(i) proteins differentially regulate murine TLR-mediated inflammatory cytokine production in a cell-specific manner in response to both LPS and gram-positive microbial stimuli.

    Funded by: NIADDK NIH HHS: AM-19318; NIGMS NIH HHS: GM-27673, GM-67202

    American journal of physiology. Cell physiology 2005;289;2;C293-301

  • Akt activation in platelets depends on Gi signaling pathways.

    Kim S, Jin J and Kunapuli SP

    Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.

    The serine-threonine kinase Akt has been established as an important signaling intermediate in regulating cell survival, cell cycle progression, as well as agonist-induced platelet activation. Stimulation of platelets with various agonists including thrombin results in Akt activation. As thrombin can stimulate multiple G protein signaling pathways, we investigated the mechanism of thrombin-induced activation of Akt. Stimulation of platelets with a PAR1-activating peptide (SFLLRN), PAR4-activating peptide (AYPGKF), and thrombin resulted in Thr308 and Ser473 phosphorylation of Akt, which results in its activation. This phosphorylation and activation of Akt were dramatically inhibited in the presence of AR-C69931MX, a P2Y12 receptor-selective antagonist, or GF 109203X, a protein kinase C inhibitor, but Akt phosphorylation was restored by supplemental Gi or Gz signaling. Unlike wild-type mouse platelets, platelets from Galphaq-deficient mice failed to trigger Akt phosphorylation by thrombin and AYPGKF, whereas Akt phosphorylation was not affected by these agonists in platelets from mice that lack P2Y1 receptor. However, ADP caused Akt phosphorylation in Galphaq- and P2Y1-deficient platelets, which was completely blocked by AR-C69931MX. In contrast, ADP failed to cause Akt phosphorylation in platelets from mice treated with clopidogrel, and thrombin and AYPGKF induced minimal phosphorylation of Akt, which was not affected by AR-C69931MX in these platelets. These data demonstrate that Gi, but not Gq or G12/13, signaling pathways are required for activation of Akt in platelets, and Gi signaling pathways, stimulated by secreted ADP, play an essential role in the activation of Akt in platelets.

    Funded by: NHLBI NIH HHS: HL60683, HL64943

    The Journal of biological chemistry 2004;279;6;4186-95

  • Removal of G(ialpha1) constraints on adenylyl cyclase in the hippocampus enhances LTP and impairs memory formation.

    Pineda VV, Athos JI, Wang H, Celver J, Ippolito D, Boulay G, Birnbaumer L and Storm DR

    Department of Pharmacology, The University of Washington, Seattle, 98195, USA.

    Stimulation of adenylyl cyclase in the hippocampus is critical for memory formation. However, generation of cAMP signals within an optimal range for memory may require a balance between stimulatory and inhibitory mechanisms. The role of adenylyl cyclase inhibitory mechanisms for memory has not been addressed. One of the mechanisms for inhibition of adenylyl cyclase is through activation of G(i)-coupled receptors, a mechanism that could serve as a constraint on memory formation. Here we report that ablation of G(ialpha1) by gene disruption increases hippocampal adenylyl cyclase activity and enhances LTP in area CA1. Furthermore, gene ablation of G(ialpha1) or antisense oligonucleotide-mediated depletion of G(ialpha1) disrupted hippocampus-dependent memory. We conclude that G(ialpha1) provides a critical mechanism for tonic inhibition of adenylyl cyclase activity in the hippocampus. We hypothesize that loss of G(ialpha1) amplifies the responsiveness of CA1 postsynaptic neurons to stimuli that strengthen synaptic efficacy, thereby diminishing synapse-specific plasticity required for new memory formation.

    Funded by: NIDCD NIH HHS: DC04156; NIDDK NIH HHS: DK-19318; NIGMS NIH HHS: 32 GM07270; NIMH NIH HHS: 1F31MH064311; NINDS NIH HHS: 1F31NS042475, NS 20498

    Neuron 2004;41;1;153-63

  • Costimulation of Gi- and G12/G13-mediated signaling pathways induces integrin alpha IIbbeta 3 activation in platelets.

    Nieswandt B, Schulte V, Zywietz A, Gratacap MP and Offermanns S

    Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, 97078 Würzburg, Germany. bernhard.nieswandt@virchow.uni-wuerzburg.de

    Platelet activation is a complex process induced by a variety of stimuli, which act in concert to ensure the rapid formation of a platelet plug at places of vascular injury. We show here that fibrillar collagen, which initiates platelet activation at the damaged vessel wall, activates only a small fraction of platelets in suspension directly, whereas the majority of platelets becomes activated by mediators released from collagen-activated platelets. In Galpha(q)-deficient platelets that do not respond with activation of integrin alpha(IIb)beta(3) to a variety of mediators like thromboxane A2 (TXA2), thrombin, or ADP, collagen at high concentrations was able to induce aggregation, an effect that could be blocked by antagonists of the TXA2 or P2Y12 receptors. The activation of TXA2 or P2Y12 receptors alone, which in Galpha(q)-deficient platelets couple to G12/G13 and Gi, respectively, did not induce platelet integrin activation or aggregation. However, concomitant activation of both receptors resulted in irreversible integrin alpha(IIb)beta3-mediated aggregation of Galpha(q)-deficient platelets. Thus, the activation of G12/G13- and Gi-mediated signaling pathways is sufficient to induce integrin alpha(IIb)beta3 activation. Although G(q)-mediated signaling plays an important role in platelet activation, it is not strictly required for the activation of integrin alpha(IIb)beta3. This indicates that the efficient induction of platelet aggregation through G-protein-coupled receptors is an integrated response mediated by various converging G-protein-mediated signaling pathways involving G(q) and G(i) as well as G12/G13.

    The Journal of biological chemistry 2002;277;42;39493-8

  • Most central nervous system D2 dopamine receptors are coupled to their effectors by Go.

    Jiang M, Spicher K, Boulay G, Wang Y and Birnbaumer L

    Department of Anesthesiology, University of California, Los Angeles, CA 90095-7115, USA.

    We reported previously that Go-deficient mice develop severe neurological defects that include hyperalgesia, a generalized tremor, lack of coordination, and a turning syndrome somewhat reminiscent of unilateral lesions of the dopaminergic nigro-striatal pathway. By using frozen coronal sections of serially sectioned brains of normal and Go-deficient mice, we studied the ability of several G protein coupled receptors to promote binding of GTPgammaS to G proteins and the ability of GTP to promote a shift in the affinity of D2 dopamine receptor for its physiologic agonist dopamine. We found a generalized, but not abolished reduction in agonist-stimulated binding of GTPgammaS to frozen brain sections, with no significant left-right differences. Unexpectedly, the ability of GTP to regulate the binding affinity of dopamine to D2 receptors (as seen in in situ [(35)S]sulpiride displacement curves) that was robust in control mice, was absent in Go-deficient mice. The data suggest that most of the effects of the Gi/Go-coupled D2 receptors in the central nervous system are mediated by Go instead of Gi1, Gi2, or Gi3. In agreement with this, the effect of GTP on dopamine binding to D2 receptors in double Gi1 plus Gi2- and Gi1 plus Gi3-deficient mice was essentially unaffected.

    Funded by: NIDDK NIH HHS: DK-19318

    Proceedings of the National Academy of Sciences of the United States of America 2001;98;6;3577-82

  • Genome-wide expression profiling of mid-gestation placenta and embryo using a 15,000 mouse developmental cDNA microarray.

    Tanaka TS, Jaradat SA, Lim MK, Kargul GJ, Wang X, Grahovac MJ, Pantano S, Sano Y, Piao Y, Nagaraja R, Doi H, Wood WH, Becker KG and Ko MS

    Laboratory of Genetics and DNA Array Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224-6820, USA.

    cDNA microarray technology has been increasingly used to monitor global gene expression patterns in various tissues and cell types. However, applications to mammalian development have been hampered by the lack of appropriate cDNA collections, particularly for early developmental stages. To overcome this problem, a PCR-based cDNA library construction method was used to derive 52,374 expressed sequence tags from pre- and peri-implantation embryos, embryonic day (E) 12.5 female gonad/mesonephros, and newborn ovary. From these cDNA collections, a microarray representing 15,264 unique genes (78% novel and 22% known) was assembled. In initial applications, the divergence of placental and embryonic gene expression profiles was assessed. At stage E12.5 of development, based on triplicate experiments, 720 genes (6.5%) displayed statistically significant differences in expression between placenta and embryo. Among 289 more highly expressed in placenta, 61 placenta-specific genes encoded, for example, a novel prolactin-like protein. The number of genes highly expressed (and frequently specific) for placenta has thereby been increased 5-fold over the total previously reported, illustrating the potential of the microarrays for tissue-specific gene discovery and analysis of mammalian developmental programs.

    Proceedings of the National Academy of Sciences of the United States of America 2000;97;16;9127-32

  • Large-scale cDNA analysis reveals phased gene expression patterns during preimplantation mouse development.

    Ko MS, Kitchen JR, Wang X, Threat TA, Wang X, Hasegawa A, Sun T, Grahovac MJ, Kargul GJ, Lim MK, Cui Y, Sano Y, Tanaka T, Liang Y, Mason S, Paonessa PD, Sauls AD, DePalma GE, Sharara R, Rowe LB, Eppig J, Morrell C and Doi H

    ERATO Doi Bioasymmetry Project, JST, Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48202, USA. kom@grc.nia.nih.gov

    Little is known about gene action in the preimplantation events that initiate mammalian development. Based on cDNA collections made from each stage from egg to blastocyst, 25438 3'-ESTs were derived, and represent 9718 genes, half of them novel. Thus, a considerable fraction of mammalian genes is dedicated to embryonic expression. This study reveals profound changes in gene expression that include the transient induction of transcripts at each stage. These results raise the possibility that development is driven by the action of a series of stage-specific expressed genes. The new genes, 798 of them placed on the mouse genetic map, provide entry points for analyses of human and mouse developmental disorders.

    Funded by: NICHD NIH HHS: R01HD32243

    Development (Cambridge, England) 2000;127;8;1737-49

  • Expression of adenylyl cyclase mRNAs in the denervated and in the developing mouse skeletal muscle.

    Suzuki Y, Shen T, Poyard M, Best-Belpomme M, Hanoune J and Defer N

    Institut National de la Sante et la Recherche Medicale Unite 99, Hopital Henri Mondor, F-94010 Creteil, France.

    Changes in the activity and in the expression of adenylyl cyclase (AC) were examined in mouse skeletal muscle after denervation and during development. Four isoforms of AC (AC2, AC6, AC7, and AC9) were detected by Northern blot analysis in gastrocnemius muscle, AC9 being the most abundant. After denervation, the levels of AC2 and AC9 mRNA decreased, whereas those of AC6 and AC7 increased. AC activity in response to several neurotransmitters was increased after denervation. During development, AC activity was high in fetus and neonate and declined in the adult; the sensitivity of AC activity to various neurotransmitters was the highest on the third postnatal day. The levels of AC6 and AC7 mRNAs were high on the third postnatal day and then decreased in adult, paralleling the decline in AC activity. All the characteristics of AC expression and activity in fetus and neonate resembled those observed in denervated adult muscle. These results indicate that changes in AC activity and AC mRNAs play an important role in the various physiopathological states of skeletal muscle, especially during muscle atrophy.

    The American journal of physiology 1998;274;6;C1674-85

  • Genetic mapping of 262 loci derived from expressed sequences in a murine interspecific cross using single-strand conformational polymorphism analysis.

    Brady KP, Rowe LB, Her H, Stevens TJ, Eppig J, Sussman DJ, Sikela J and Beier DR

    Division of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.

    We have demonstrated previously that noncoding sequences of genes are a robust source of polymorphisms between mouse species when tested using single-strand conformation polymorphism (SSCP) analysis, and that these polymorphisms are useful for genetic mapping. In this report we demonstrate that presumptive 3'-untranslated region sequence obtained from expressed sequence tags (ESTs) can be analyzed in a similar fashion, and we have used this approach to map 262 loci using an interspecific backcross. These results demonstrate SSCP analysis of genes or ESTs is a simple and efficient means for the genetic localization of transcribed sequences, and is furthermore an approach that is applicable to any system for which there is sufficient sequence polymorphism.

    Funded by: NHGRI NIH HHS: HG00941, HG00951

    Genome research 1997;7;11;1085-93

  • Two isoforms of the mouse ether-a-go-go-related gene coassemble to form channels with properties similar to the rapidly activating component of the cardiac delayed rectifier K+ current.

    London B, Trudeau MC, Newton KP, Beyer AK, Copeland NG, Gilbert DJ, Jenkins NA, Satler CA and Robertson GA

    Division of Cardiology, University of Pittsburgh Medical Center, PA 15213-2582, USA. london@card2.cath.upmc.edu

    HERG, the human ether-a-go-go-related gene, encodes a K(+)-selective channel with properties similar to the rapidly activating component of the delayed rectifier K+ current (IKr). Mutations of HERG cause the autosomal-dominant long-QT syndrome (LQTS), presumably by disrupting the normal function of IKr. The current produced by HERG is not identical to IKr, however, and the mechanism by which HERG mutations cause LQTS remains uncertain. To better define the role of Erg in the heart, we cloned Merg1 from mouse genomic and cardiac cDNA libraries. Merg1 has 16 exons and maps to mouse chromosome 5 in an area syntenic to human chromosome 7q, the map locus of HERG. We isolated three cardiac isoforms of Merg1: Merg1a is homologous to HERG and is expressed in heart, brain, and testes, Merg1a' lacks the first 59 amino acids of Merg1a and is not expressed abundantly, and Merg1b has a markedly shorter divergent N-terminal cytoplasmic domain and is expressed specifically in the heart. The Merg1 isoforms, like HERG, produce inwardly rectifying E-4031-sensitive currents when heterologously expressed in Xenopus oocytes. Merg1a and HERG produce currents with slow deactivation kinetics, whereas Merg1a' and Merg1b currents deactivate more rapidly. Merg1b coassembles with Merg1a to form channels with deactivation kinetics that are more rapid than those of Merg1a or HERG and nearly identical to IKr. In addition, a homologue of Merg1b is present in human cardiac and smooth muscle. Thus, we have identified a novel N-terminal Erg isoform that is expressed specifically in the heart, has rapid deactivation kinetics, and coassembles with the longer isoform in Xenopus oocytes. This N-terminal Erg isoform may determine the properties of IKr and contribute to the pathogenesis of LQTS.

    Funded by: NHLBI NIH HHS: K08 HL-02843, R01 HL-55793

    Circulation research 1997;81;5;870-8

  • G protein gene expression during mouse oocyte growth and maturation, and preimplantation embryo development.

    Williams CJ, Schultz RM and Kopf GS

    Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia 19104-6080, USA.

    Fertilization in mammals initiates "egg activation," a series of events leading to embryo development. The signal transduction events that occur as a result of sperm-egg interactions and that initiate egg activation may be analogous to a ligand-receptor-effector pathway, but the details of this signaling pathway are poorly understood. Several lines of evidence support a role for guanine nucleotide-binding regulatory proteins (G proteins) in mammalian egg activation. Prior to initiating studies to examine further the role of specific G proteins in sperm-induced mouse egg activation, we needed to define the complement of G proteins expressed in the egg. Using a reverse transcription-polymerase chain reaction (RT-PCR) assay, the relative levels of mRNAs encoding specific G protein alpha, beta, and gamma subunits were determined in meiotically incompetent oocytes, fully-grown competent oocytes, metaphase II-arrested eggs, one-, two-, and eight-cell embryos, and blastocysts. mRNA transcripts representing all of the heterotrimeric G protein families were present at all of the stages examined, and all underwent significant changes in their patterns of expression. The following heterotrimeric G protein mRNA transcripts were present in oocytes, eggs, or preimplantation embryos: G alpha q family (q, 11, and 14), G alpha 12 family (12 and 13), G alpha i family (i1, i2, i3, t2, z, and s), beta subunits 1, 2, 4, and 5, and gamma subunits 2, 3, 5, and 7. A recently described large molecular weight G protein, G alpha h (Nakaoka et al., 1994: Science 264:1593-1596), was also present, G alpha 15, G alpha t1, G alpha olf, G alpha oA, G beta 3, G gamma 1, and G gamma 8 mRNA transcripts were not detected using this method. The most common pattern of expression observed was a maturation-associated decrease followed by an increase after the two-cell stage. Some transcripts, however, were expressed at low levels until the eight-cell to blastocyst stages, whereas others were expressed at high levels in the oocyte but following maturation declined and remained at a low level throughout preimplantation development.

    Funded by: NICHD NIH HHS: HD 22732, K11 HD 00985

    Molecular reproduction and development 1996;44;3;315-23

  • A large family of putative transmembrane receptors homologous to the product of the Drosophila tissue polarity gene frizzled.

    Wang Y, Macke JP, Abella BS, Andreasson K, Worley P, Gilbert DJ, Copeland NG, Jenkins NA and Nathans J

    Department of Molecular Biology, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.

    In Drosophila melanogaster, the frizzled gene plays an essential role in the development of tissue polarity as assessed by the orientation of cuticular structures. Through a combination of random cDNA sequencing, degenerate polymerase chain reaction amplification, and low stringency hybridization we have identified six novel frizzled homologues from mammals, at least 11 from zebrafish, several from chicken and sea urchin, and one from Caenorhabditis elegans. The complete deduced amino acid sequences of the mammalian and nematode homologues share with the Drosophila frizzled protein a conserved amino-terminal cysteine-rich domain and seven putative transmembrane segments. Each of the mammalian homologues is expressed in a distinctive set of tissues in the adult, and at least three are expressed during embryogenesis. As hypothesized for the Drosophila frizzled protein, the frizzled homologues are likely to act as transmembrane receptors for as yet unidentified ligands. These observations predict the existence of a family of signal transduction pathways that are homologous to the pathway that determines tissue polarity in Drosophila.

    The Journal of biological chemistry 1996;271;8;4468-76

  • Cloning, expression, and chromosomal location of SHH and IHH: two human homologues of the Drosophila segment polarity gene hedgehog.

    Marigo V, Roberts DJ, Lee SM, Tsukurov O, Levi T, Gastier JM, Epstein DJ, Gilbert DJ, Copeland NG, Seidman CE et al.

    Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.

    The hedgehog genes encode signaling molecules that play a role in regulating embryonic morphogenesis. We have cloned and sequenced human cDNA copies of two of these genes, SHH and IHH. The SHH clone includes the full coding sequence and encodes a protein 92.4% identical to its murine homologue. The IHH clone is 89% complete and encodes a protein 94.6% identical to its murine homologue. IHH is expressed in adult kidney and liver. SHH expression was not detected in adult tissues examined; however, it is expressed in fetal intestine, liver, lung, and kidney. SHH mapped to chromosome 7q and IHH to chromosome 2 by PCR with DNA from a panel of rodent-human somatic cell hybrids. To identify the chromosomal location of SHH more precisely, a P1 genomic clone of SHH was isolated. This phage contained a CA repeat sequence tagged site that was used to map SHH relative to a polysyndactyly disease locus, using DNA prepared from affected and unaffected members of a large pedigree. SHH is closely linked, but distinct from the polysyndactyly disease locus at 7q36 (maximum lod score = 4.82, theta = 0.05) tightly linked to the EN2 locus. The murine homologues Shh, Ihh, and Dhh were mapped using (C57BL/6J x Mus spretus)F1 x C57BL/6J interspecific backcross. Shh mapped to a position 0.6 cM distal to En2 and 1.9 cM proximal to Il6 on mouse chromosome 5. This location is closely linked but distinct from the murine limb mutation Hx and syntenic to human chromosome 7q36.

    Funded by: NCI NIH HHS: N0I-CO-46000; NICHD NIH HHS: HD01060

    Genomics 1995;28;1;44-51

  • Isolation of an allele of reeler by insertional mutagenesis.

    Miao GG, Smeyne RJ, D'Arcangelo G, Copeland NG, Jenkins NA, Morgan JI and Curran T

    Roche Institute of Molecular Biology, Nutley, NJ 07110.

    Reeler (rl) is an autosomal recessive mutation that affects migration of postmitotic neurons in the mouse central nervous system. The reeler (rl/rl) mouse displays a disruption of laminar structures in both the cerebellum and the forebrain and it exhibits tremors, dystonia, and ataxia. The molecular basis of the reeler phenotype is unknown because the gene involved has not yet been identified. We report here the isolation and characterization of an allele of rl, reelertransgene (rltg). This allele was generated by the fortuitous insertion of a transgene, supfos (sf), into the mouse rl locus. Crosses between rl/+ and rltg/+ mice yielded offspring that exhibited the reeler phenotype, indicating that rl and rltg are allelic. We cloned the genomic sequences flanking the transgene insertion site from the rltg/rltg mouse genome. Chromosomal mapping studies revealed that the 5' flanking cellular sequence maps to a locus, D5Gmr1, that lies in a region of mouse chromosome 5 that also contains the rl locus. Southern blot analysis using a probe derived from the D5Gmr1 locus revealed no gross structural rearrangement in the rl locus. Thus, unlike the two rl alleles described previously, rltg provides a molecular probe that can now be used to identify and isolate the rl gene.

    Funded by: NCI NIH HHS: N01-CO-74101; NINDS NIH HHS: NS09698-01

    Proceedings of the National Academy of Sciences of the United States of America 1994;91;23;11050-4

  • Evolution of the mammalian G protein alpha subunit multigene family.

    Wilkie TM, Gilbert DJ, Olsen AS, Chen XN, Amatruda TT, Korenberg JR, Trask BJ, de Jong P, Reed RR, Simon MI et al.

    Biology Division, California Institute of Technology, Pasadena 91125.

    Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. The multigene family of G protein alpha subunits, which interact with receptors and effectors, exhibit a high level of sequence diversity. In mammals, 15 G alpha subunit genes can be grouped by sequence and functional similarities into four classes. We have determined the murine chromosomal locations of all 15 G alpha subunit genes using an interspecific backcross derived from crosses of C57BL/6J and Mus spretus mice. These data, in combination with mapping studies in humans, have provided insight into the events responsible for generating the genetic diversity found in the mammalian alpha subunit genes and a framework for elucidating the role of the G alpha subunits in disease.

    Nature genetics 1992;1;2;85-91

  • Diversity of the G-protein family: sequences from five additional alpha subunits in the mouse.

    Strathmann M, Wilkie TM and Simon MI

    Division of Biology, California Institute of Technology, Pasadena 91125.

    Biochemical analysis has revealed a number of guanine nucleotide-binding regulatory proteins (G proteins) that mediate signal transduction in mammalian systems. Characterization of their cDNAs uncovered a family of proteins with regions of highly conserved amino acid sequence. To examine the extent of diversity of the G protein family, we used the polymerase chain reaction to detect additional gene products in mouse brain and spermatid RNA that share these conserved regions. Sequences corresponding to six of the eight known G protein alpha subunits were obtained. In addition, we found sequences corresponding to five newly discovered alpha subunits. Our results suggest that the complexity of the G protein family is much greater than previously suspected.

    Proceedings of the National Academy of Sciences of the United States of America 1989;86;19;7407-9

  • Chromosomal localization of genes encoding guanine nucleotide-binding protein subunits in mouse and human.

    Blatt C, Eversole-Cire P, Cohn VH, Zollman S, Fournier RE, Mohandas LT, Nesbitt M, Lugo T, Jones DT, Reed RR et al.

    Weizmann Institute, Rehovoth, Israel.

    A variety of genes have been identified that specify the synthesis of the components of guanine nucleotide-binding proteins (G proteins). Eight different guanine nucleotide-binding alpha-subunit proteins, two different beta subunits, and one gamma subunit have been described. Hybridization of cDNA clones with DNA from human-mouse somatic cell hybrids was used to assign many of these genes to human chromosomes. The retinal-specific transducin subunit genes GNAT1 and GNAT2 were on chromosomes 3 and 1; GNAI1, GNAI2, and GNAI3 were assigned to chromosomes 7, 3, and 1, respectively; GNAZ and GNAS were found on chromosomes 22 and 20. The beta subunits were also assigned--GNB1 to chromosome 1 and GNB2 to chromosome 7. Restriction fragment length polymorphisms were used to map the homologues of some of these genes in the mouse. GNAT1 and GNAI2 were found to map adjacent to each other on mouse chromosome 9 and GNAT2 was mapped on chromosome 17. The mouse GNB1 gene was assigned to chromosome 19. These mapping assignments will be useful in defining the extent of the G alpha gene family and may help in attempts to correlate specific genetic diseases with genes corresponding to G proteins.

    Proceedings of the National Academy of Sciences of the United States of America 1988;85;20;7642-6

  • Molecular cloning of five GTP-binding protein cDNA species from rat olfactory neuroepithelium.

    Jones DT and Reed RR

    Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.

    Biochemical studies in vertebrate olfactory tissue indicate that certain odorants stimulate adenylyl cyclase in a GTP-dependent manner. Additionally, immunochemical and toxin-labeling studies demonstrate the presence of several GTP-binding protein (G-protein) species in vertebrate olfactory epithelium. To identify the G-protein(s) responsible for olfactory signal transduction, we screened a rat olfactory cDNA library with an oligonucleotide probe and isolated 32 recombinant clones encoding five distinct types of G-protein alpha subunits. The majority of the clones encoded G alpha s, while the remaining clones encoded G alpha o, G alpha i1, G alpha i2, and a novel species, G alpha i3. Messenger RNA corresponding to each G alpha was detectable in all tissues examined; however, the levels for a given G alpha varied in a tissue-specific manner. In olfactory tissue, G alpha s was the most abundant of these messages and in combination with the biochemical studies suggests that G alpha s is the G-protein component of the olfactory signal transduction cascade.

    The Journal of biological chemistry 1987;262;29;14241-9

  • Inhibitory and stimulatory G proteins of adenylate cyclase: cDNA and amino acid sequences of the alpha chains.

    Sullivan KA, Liao YC, Alborzi A, Beiderman B, Chang FH, Masters SB, Levinson AD and Bourne HR

    The G protein family of signal transducers includes five heterotrimers, which are most clearly distinguished by their different alpha chains. The family includes Gs and Gi, the stimulatory and inhibitory GTP-binding regulators of adenylate cyclase; Go, a protein of unknown function abundant in brain; and transducin 1 and transducin 2, proteins involved in retinal phototransduction. Using a bovine alpha t1 cDNA as a hybridization probe, we have isolated mouse cDNAs that encode alpha chains of two G proteins. One encodes a polypeptide of 377 amino acids (Mr 43,856), identified as alpha s because it specifically fails to hybridize with any transcript in an alpha s-deficient S49 mouse lymphoma mutant, cyc-; the other encodes a polypeptide of 355 amino acids (Mr 40,482), presumed to be alpha i. These alpha chains and those of the retinal transducins exhibit impressive sequence homology. Of the four, alpha t1 and alpha t2 are most alike (81% identical amino acid residues), whereas the presumptive alpha i is more similar than alpha s to alpha t1 (63% vs. 38% identical residues). Sequence homologies with p21ras and elongation factor Tu identify regions of the alpha chains that form the site for GTP binding and hydrolysis. Further comparison of the alpha-chain sequences suggests additional regions that may contribute to interactions with beta gamma subunits and the receptor and effector components of different signal transduction systems.

    Funded by: NHLBI NIH HHS: HL07192; NIGMS NIH HHS: GM27800, GM28310

    Proceedings of the National Academy of Sciences of the United States of America 1986;83;18;6687-91

Gene lists (3)

Gene List Source Species Name Description Gene count
L00000062 G2C Mus musculus BAYES-COLLINS-MOUSE-PSD-CONSENSUS Mouse cortex PSD consensus 984
L00000070 G2C Mus musculus BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list (ortho) 1461
L00000072 G2C Mus musculus BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list 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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