Gene Symbol: gnat2
Description: guanine nucleotide binding protein (G protein), alpha transducing activity polypeptide 2
Alias: guanine nucleotide-binding protein G(t) subunit alpha-2, GNAT3, Galpha t2, T alpha C, Tc alpha, cone transducin alpha subunit, no optokinetic response f, nof, transducin alpha (cone)
Species: zebrafish

Top Publications

  1. Kennedy B, Alvarez Y, Brockerhoff S, Stearns G, Sapetto Rebow B, Taylor M, et al. Identification of a zebrafish cone photoreceptor-specific promoter and genetic rescue of achromatopsia in the nof mutant. Invest Ophthalmol Vis Sci. 2007;48:522-9 pubmed
    ..Achromatopsia in the nof mutant was rescued using the identified promoter fragment to direct transgenic expression of wild-type cone ..
  2. Brockerhoff S, Rieke F, Matthews H, Taylor M, Kennedy B, Ankoudinova I, et al. Light stimulates a transducin-independent increase of cytoplasmic Ca2+ and suppression of current in cones from the zebrafish mutant nof. J Neurosci. 2003;23:470-80 pubmed
    ..Here we describe a zebrafish mutant, no optokinetic response f(w21) (nof), with a nonsense mutation in the gene encoding the alpha subunit of cone transducin...
  3. Linder B, Dill H, Hirmer A, Brocher J, Lee G, Mathavan S, et al. Systemic splicing factor deficiency causes tissue-specific defects: a zebrafish model for retinitis pigmentosa. Hum Mol Genet. 2011;20:368-77 pubmed publisher
    ..Hence, various routes affecting the tri-snRNP can elicit tissue-specific gene expression defects and lead to the RP phenotype. ..
  4. Lewis A, Williams P, Lawrence O, Wong R, Brockerhoff S. Wild-type cone photoreceptors persist despite neighboring mutant cone degeneration. J Neurosci. 2010;30:382-9 pubmed publisher
    ..Our results suggest a potential for the therapeutic transplantation of healthy cones into an environment of damaged cones. ..
  5. Li X, Montgomery J, Cheng W, Noh J, Hyde D, Li L. Pineal photoreceptor cells are required for maintaining the circadian rhythms of behavioral visual sensitivity in zebrafish. PLoS ONE. 2012;7:e40508 pubmed publisher
    ..We generated a transgenic zebrafish line [Tg(Gnat2:gal4-VP16/UAS:nfsB-mCherry)] in which the E. coli nitroreductase is expressed in pineal photoreceptor cells...
  6. Suzuki S, Bleckert A, Williams P, Takechi M, Kawamura S, Wong R. Cone photoreceptor types in zebrafish are generated by symmetric terminal divisions of dedicated precursors. Proc Natl Acad Sci U S A. 2013;110:15109-14 pubmed publisher
    ..Ectopic expression of tr?2 after cone differentiation produces cones with mixed opsins. Temporal differences in the onset of tr?2 expression could explain why some species have mixed, and others have pure, cone types. ..
  7. Smyth V, Di Lorenzo D, Kennedy B. A novel, evolutionarily conserved enhancer of cone photoreceptor-specific expression. J Biol Chem. 2008;283:10881-91 pubmed publisher
    ..Bioinformatic alignments reveal that CPRE-1 sites are evolutionarily conserved in the promoter regions of fish, rodent, and mammalian TalphaC orthologues and identify a 5'-CTGGAGTG(A/T)TGGA(G/A)GCAGGG(G/C)T-3' consensus sequence. ..
  8. Liu Q, Frey R, Babb Clendenon S, Liu B, Francl J, Wilson A, et al. Differential expression of photoreceptor-specific genes in the retina of a zebrafish cadherin2 mutant glass onion and zebrafish cadherin4 morphants. Exp Eye Res. 2007;84:163-75 pubmed
    ..photoreceptors, we have analyzed expression patterns of several photoreceptor-specific genes (crx, gnat1, gnat2, irbp, otx5, rod opsin, rx1, and uv opsin) and/or a cone photoreceptor marker (zpr-1) in the retina of a zebrafish ..
  9. Insinna C, Baye L, Amsterdam A, Besharse J, Link B. Analysis of a zebrafish dync1h1 mutant reveals multiple functions for cytoplasmic dynein 1 during retinal photoreceptor development. Neural Dev. 2010;5:12 pubmed publisher
    ..Proper morphogenesis of photoreceptor neurons is essential for their normal function and survival. We have characterized a zebrafish mutation, cannonball, that completely disrupts photoreceptor morphogenesis...

More Information


  1. Nelson S, Frey R, Wardwell S, Stenkamp D. The developmental sequence of gene expression within the rod photoreceptor lineage in embryonic zebrafish. Dev Dyn. 2008;237:2903-17 pubmed publisher
  2. Nelson S, Park L, Stenkamp D. Retinal homeobox 1 is required for retinal neurogenesis and photoreceptor differentiation in embryonic zebrafish. Dev Biol. 2009;328:24-39 pubmed publisher
  3. Holzhausen L, Lewis A, Cheong K, Brockerhoff S. Differential role for synaptojanin 1 in rod and cone photoreceptors. J Comp Neurol. 2009;517:633-44 pubmed publisher
    ..Given the known involvement of SynJ1 in synaptic vesicle endocytosis, we hypothesize that rods and cones use distinct mechanisms for vesicle recycling. ..
  4. Shen Y, Raymond P. Zebrafish cone-rod (crx) homeobox gene promotes retinogenesis. Dev Biol. 2004;269:237-51 pubmed
    ..These results suggest novel functions for zebrafish crx during retinal specification and differentiation. ..
  5. Daniele L, Emran F, Lobo G, Gaivin R, Perkins B. Mutation of wrb, a Component of the Guided Entry of Tail-Anchored Protein Pathway, Disrupts Photoreceptor Synapse Structure and Function. Invest Ophthalmol Vis Sci. 2016;57:2942-54 pubmed publisher
    ..Proteins Wrb and Trc40 are required for synaptic transmission between photoreceptors and bipolar cells, indicating that TA protein insertion by the TRC pathway is a critical step in ribbon synapse assembly and function. ..
  6. Yang L, Kemadjou J, Zinsmeister C, Bauer M, Legradi J, Muller F, et al. Transcriptional profiling reveals barcode-like toxicogenomic responses in the zebrafish embryo. Genome Biol. 2007;8:R227 pubmed
    ..Our work provides proof-of-principle for the use of the zebrafish embryo as a toxicogenomic model and highlights its potential for systematic, large-scale analysis of the effects of chemicals on the developing vertebrate embryo. ..
  7. Feng D, Chen Z, Yang K, Miao S, Xu B, Kang Y, et al. The cytoplasmic tail of rhodopsin triggers rapid rod degeneration in kinesin-2 mutants. J Biol Chem. 2017;292:17375-17386 pubmed publisher
    ..Our results demonstrate a previously unknown function of the rhodopsin cytoplasmic domain during opsin-triggered photoreceptor degeneration and may open up new avenues for managing this disease. ..
  8. Bachmann Gagescu R, Phelps I, Stearns G, Link B, Brockerhoff S, Moens C, et al. The ciliopathy gene cc2d2a controls zebrafish photoreceptor outer segment development through a role in Rab8-dependent vesicle trafficking. Hum Mol Genet. 2011;20:4041-55 pubmed publisher
    ..Our data support a model where Cc2d2a, localized at the photoreceptor connecting cilium/transition zone, facilitates protein transport through a role in Rab8-dependent vesicle trafficking and fusion. ..
  9. Kennedy M, Dunn F, Hurley J. Visual pigment phosphorylation but not transducin translocation can contribute to light adaptation in zebrafish cones. Neuron. 2004;41:915-28 pubmed
    ..Immunocytochemical analyses revealed that neither light nor cytoplasmic Ca2+ influences the localization of transducin in zebrafish cones. ..
  10. Chen J, Huang C, Truong L, La Du J, Tilton S, Waters K, et al. Early life stage trimethyltin exposure induces ADP-ribosylation factor expression and perturbs the vascular system in zebrafish. Toxicology. 2012;302:129-39 pubmed publisher
    ..When arf5 expression was blocked by morpholinos, the zebrafish did not display the prototypical TMT-induced vascular deficits, indicating that the induction of arf5 was necessary for TMT-induced vascular toxicity. ..
  11. George A, Hayden S, Stanton G, Brockerhoff S. Arf6 and the 5'phosphatase of synaptojanin 1 regulate autophagy in cone photoreceptors. Bioessays. 2016;38 Suppl 1:S119-35 pubmed publisher
    ..Our study describes a specific role for SynJ1 in autophagosomal and endosomal trafficking and provides evidence that PI(4,5)P2 participates in autophagy in a neuronal cell type. ..
  12. Li W, Zhou L, Li Z, Wang Y, Shi J, Yang Y, et al. Zebrafish Lbh-like Is Required for Otx2-mediated Photoreceptor Differentiation. Int J Biol Sci. 2015;11:688-700 pubmed publisher morpholinos specifically inhibits expression of multiple photoreceptor-specific genes, such as opsins, gnat1, gnat2 and irbp...
  13. Muto A, Taylor M, Suzawa M, Korenbrot J, Baier H. Glucocorticoid receptor activity regulates light adaptation in the zebrafish retina. Front Neural Circuits. 2013;7:145 pubmed publisher
    ..We suggest that GR controls a gene network required for visual adaptation in the zebrafish retina and potentially integrates neuroendocrine and sensory responses to environmental changes. ..
  14. Bader J, Kusik B, Besharse J. Analysis of KIF17 distal tip trafficking in zebrafish cone photoreceptors. Vision Res. 2012;75:37-43 pubmed publisher
    ..In some cases KIF17-GFP is shed with the OS tip as part of the disc shedding process. We have also found that KIF17-GFP moves within the OS at rates consistent with those observed for IFT and other kinesins. ..
  15. Oka Y, Korsching S. Shared and unique G alpha proteins in the zebrafish versus mammalian senses of taste and smell. Chem Senses. 2011;36:357-65 pubmed publisher
    ..Our results show general similarity to the mammalian situation but also clear-cut differences and as such are essential for using the zebrafish model system to study chemosensory perception...
  16. Lagman D, Callado Pérez A, Franzén I, Larhammar D, Abalo X. Transducin duplicates in the zebrafish retina and pineal complex: differential specialisation after the teleost tetraploidisation. PLoS ONE. 2015;10:e0121330 pubmed publisher
    ..Early vertebrate tetraploidisations resulted in separate transducin heterotrimers: gnat1/gnb1/gngt1 for rods, and gnat2/gnb3/gngt2 for cones...
  17. George A, Hayden S, Holzhausen L, Ma E, Suzuki S, Brockerhoff S. Synaptojanin 1 is required for endolysosomal trafficking of synaptic proteins in cone photoreceptor inner segments. PLoS ONE. 2014;9:e84394 pubmed publisher
    ..This last pathway also appears exacerbated by darkness. Taken altogether, these findings show that SynJ1 is required in cones for normal endolysosomal trafficking of synaptic proteins. ..
  18. Huang L, Zuo Z, Zhang Y, Wu M, Lin J, Wang C. Use of toxicogenomics to predict the potential toxic effect of Benzo(a)pyrene on zebrafish embryos: ocular developmental toxicity. Chemosphere. 2014;108:55-61 pubmed publisher
    ..Our results were helpful for an understanding of the toxicity of BaP. This study also indicated that microarray analysis was effective for predicting the potential toxicity of chemicals with high sensitivity and accuracy. ..
  19. Bailey T, Fossum S, Fimbel S, Montgomery J, Hyde D. The inhibitor of phagocytosis, O-phospho-L-serine, suppresses Müller glia proliferation and cone cell regeneration in the light-damaged zebrafish retina. Exp Eye Res. 2010;91:601-12 pubmed publisher
    ..This implies that at least one signaling mechanism, in addition to the process disrupted by L-SOP, is required to activate Müller glia proliferation in the light-damaged retina. ..
  20. Zhang L, Zhang X, Zhang G, Pang C, Leung Y, Zhang M, et al. Expression profiling of the retina of pde6c, a zebrafish model of retinal degeneration. Sci Data. 2017;4:170182 pubmed publisher
    ..This dataset will facilitate the characterization of the molecular defects in the pde6c retina at the initial stage of retinal degeneration. ..
  21. Yu S, Li C, Biswas L, Hu X, Liu F, Reilly J, et al. CERKL gene knockout disturbs photoreceptor outer segment phagocytosis and causes rod-cone dystrophy in zebrafish. Hum Mol Genet. 2017;26:2335-2345 pubmed publisher
    ..We conclude that CERKL deficiency in zebrafish may cause rod-cone dystrophy, but not cone-rod dystrophy, while interfering with the phagocytosis function of RPE associated with down-regulation of the expression of MERTK. ..
  22. Glaviano A, Smith A, Blanco A, McLoughlin S, Cederlund M, Heffernan T, et al. A method for isolation of cone photoreceptors from adult zebrafish retinae. BMC Neurosci. 2016;17:71 pubmed
    ..In addition, this advancement facilitates the identification of novel candidate genes for inherited human blindness. ..
  23. Oka Y, Saraiva L, Kwan Y, Korsching S. The fifth class of Galpha proteins. Proc Natl Acad Sci U S A. 2009;106:1484-9 pubmed publisher
    ..The discovery of this fifth class of Galpha proteins changes our understanding of G protein evolution. ..
  24. Wang T, Holzhausen L, Kramer R. Imaging an optogenetic pH sensor reveals that protons mediate lateral inhibition in the retina. Nat Neurosci. 2014;17:262-8 pubmed publisher
    ..These findings reveal that protons mediate lateral inhibition in the retina, raising the possibility that protons are unrecognized retrograde messengers elsewhere in the nervous system. ..
  25. Morrissey M, Shelton S, Brockerhoff S, Hurley J, Kennedy B. PRE-1, a cis element sufficient to enhance cone- and rod- specific expression in differentiating zebrafish photoreceptors. BMC Dev Biol. 2011;11:3 pubmed publisher
    ..PRE-1 is a novel cis-regulatory module that is sufficient to enhance the initiation of photoreceptor-specific gene expression in differentiating rod and cone photoreceptors. ..
  26. Collery R, Cederlund M, Kennedy B. Transgenic zebrafish expressing mutant human RETGC-1 exhibit aberrant cone and rod morphology. Exp Eye Res. 2013;108:120-8 pubmed publisher
    ..cDNAs encoding wildtype and mutant (E837D R838S) RETGC-1 were cloned under the control of the cone-specific gnat2 promoter and microinjected into zebrafish embryos to generate transgenic lines...
  27. Yin J, Brocher J, Fischer U, Winkler C. Mutant Prpf31 causes pre-mRNA splicing defects and rod photoreceptor cell degeneration in a zebrafish model for Retinitis pigmentosa. Mol Neurodegener. 2011;6:56 pubmed publisher
    ..Analyzing the AD5 effects in our animal model in vivo, our data imply that aberrant splicing of distinct retinal transcripts contributes to the observed retina defects. ..
  28. Stevens C, Cameron D, Stenkamp D. Plasticity of photoreceptor-generating retinal progenitors revealed by prolonged retinoic acid exposure. BMC Dev Biol. 2011;11:51 pubmed publisher
    ..In zebrafish RA may influence the rod vs. cone cell fate decision. The RAR?b receptor mediates the effects of endogenous, as well as exogenous RA, on rod development. ..
  29. Rainy N, Etzion T, Alon S, Pomeranz A, Nisgav Y, Livnat T, et al. Knockdown of unc119c results in visual impairment and early-onset retinal dystrophy in zebrafish. Biochem Biophys Res Commun. 2016;473:1211-1217 pubmed publisher
    ..morphology was analyzed using immunohistochemistry with anti-cone arrestin (zpr-1) and anti-cone transducin-? (GNAT2) antibodies. The zebrafish genome contains four genes encoding unc119 paralogs located on different chromosomes...
  30. Alvarez Y, Chen K, Reynolds A, Waghorne N, O Connor J, Kennedy B. Predominant cone photoreceptor dysfunction in a hyperglycaemic model of non-proliferative diabetic retinopathy. Dis Model Mech. 2010;3:236-45 pubmed publisher
    ..Our data suggest that cone photoreceptor dysfunction is a clinical hallmark of diabetic retinopathy and that the debilitating blindness associated with diabetic retinopathy may be halted by neuroprotection of cones. ..
  31. Chen X, Sheng X, Zhuang W, Sun X, Liu G, Shi X, et al. GUCA1A mutation causes maculopathy in a five-generation family with a wide spectrum of severity. Genet Med. 2017;19:945-954 pubmed publisher
    ..The diverse pathogenic modes of GUCA1A mutations may explain the phenotypic diversities.Genet Med advance online publication 26 January 2017. ..
  32. Ma E, Lewis A, Barabas P, Stearns G, Suzuki S, Krizaj D, et al. Loss of Pde6 reduces cell body Ca(2+) transients within photoreceptors. Cell Death Dis. 2013;4:e797 pubmed publisher
    ..This study thus provides insight into Ca(2+) dynamics in a common form of inherited blindness and uncovers a dramatic, light-independent modulation of [Ca(2+)]i that occurs in normal cones. ..
  33. Liu Y, Chen X, Qin B, Zhao K, Zhao Q, Staley J, et al. Knocking Down Snrnp200 Initiates Demorphogenesis of Rod Photoreceptors in Zebrafish. J Ophthalmol. 2015;2015:816329 pubmed publisher
    ..Conclusions. We conclude that knocking down Snrnp200 in zebrafish could alter regular splicing and expression of a panel of genes, which may eventually trigger rod defects. ..
  34. Takita S, Wada Y, Kawamura S. Effects of NDRG1 family proteins on photoreceptor outer segment morphology in zebrafish. Sci Rep. 2016;6:36590 pubmed publisher
    ..The result shows that rod OS membrane structure is preserved in these taper-shaped OSs and therefore, suggests that tapered OS morphology is not related to the infolded membrane structure in cone OS. ..
  35. Lewis T, Zareba M, Link B, Besharse J. Cone myoid elongation involves unidirectional microtubule movement mediated by dynein-1. Mol Biol Cell. 2018;29:180-190 pubmed publisher
    ..We propose a novel model by which stationary complexes of cytoplasmic dynein-1 are responsible for the shuttling of microtubules between the ellipsoid and myoid is the underlying force for the morphological change of myoid elongation. ..
  36. Chen X, Liu Y, Sheng X, Tam P, Zhao K, Chen X, et al. PRPF4 mutations cause autosomal dominant retinitis pigmentosa. Hum Mol Genet. 2014;23:2926-39 pubmed publisher
    ..We conclude that mutations of PRPF4 cause RP via haploinsufficiency and dominant-negative effects, and establish PRPF4 as a new U4/U6-U5 snRNP component associated with adRP. ..
  37. Warner C, Gust K, Stanley J, Habib T, Wilbanks M, Garcia Reyero N, et al. A systems toxicology approach to elucidate the mechanisms involved in RDX species-specific sensitivity. Environ Sci Technol. 2012;46:7790-8 pubmed publisher
  38. Kennedy B, Stearns G, Smyth V, Ramamurthy V, van Eeden F, Ankoudinova I, et al. Zebrafish rx3 and mab21l2 are required during eye morphogenesis. Dev Biol. 2004;270:336-49 pubmed
    ..We propose that mab21l2 is an early downstream effector of rx3 and is critical for survival of eye progenitors. ..
  39. Giarmarco M, Cleghorn W, Sloat S, Hurley J, Brockerhoff S. Mitochondria Maintain Distinct Ca2+ Pools in Cone Photoreceptors. J Neurosci. 2017;37:2061-2072 pubmed publisher
    ..Our results show that mitochondrial Ca2+ uptake in photoreceptors is complex and plays an essential role in normal function. ..