title: A shifted repertoire of endocannabinoid genes in the zebrafish (Danio rerio).
abstract: The zebrafish has served as a model organism for developmental biology. Sequencing its genome has expanded zebrafish research into physiology and drug-development testing. Several cannabinoid pharmaceuticals are in development, but expression of endocannabinoid receptors and enzymes remains unknown in this species. We conducted a bioinformatics analysis of the zebrafish genome using 17 human endocannabinoid genes as a reference set. Putative zebrafish orthologs were identified in filtered BLAST searches as reciprocal best hits. Orthology was confirmed by three in silico methods: phylogenetic testing, synteny analysis, and functional mapping. Zebrafish expressed orthologs of cannabinoid receptor 1, transient receptor potential channel vanilloid receptor 4, GPR55 receptor, fatty acid amide hydrolase 1, monoacylglycerol lipase, NAPE-selective phospholipase D, abhydrolase domain-containing protein 4, and diacylglycerol lipase alpha and beta; and paired paralogs of cannabinoid receptor 2, fatty acid amide hydrolase 2, peroxisome proliferator-activated receptor alpha, prostaglandin-endoperoxide synthase 2, and transient receptor potential cation channel subtype A1. Functional mapping suggested the orthologs of transient receptor potential vanilloid receptor 1 and peroxisome proliferator-activated receptor gamma lack specific amino acids critical for cannabinoid ligand binding. No orthologs of N-acylethanolamine acid amidase or protein tyrosine phosphatase, non-receptor type 22 were identified. In conclusion, the zebrafish genome expresses a shifted repertoire of endocannabinoid genes. In vitro analyses are warranted before using zebrafish for cannabinoid development testing.
authors.affiliation: GW Pharmaceuticals, Middlebury, VT 05753, USA. mcpruitt@verizon.net
authors.forename: J M
authors.initials: JM
authors.lastname: McPartland
authors.forename: Michelle
authors.initials: M
authors.lastname: Glass
authors.forename: Isabel
authors.initials: I
authors.lastname: Matias
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Norris
authors.forename: C William
authors.initials: CW
authors.lastname: Kilpatrick
mesh_terms: D000465:Algorithms; D000581:Amidohydrolases / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D015220:Calcium Channels; D063385:Cannabinoid Receptor Modulators / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D051546:Cyclooxygenase 2 / Q000235:genetics; D063388:Endocannabinoids; D016678:Genome; D006801:Humans; D008071:Lipoprotein Lipase / Q000235:genetics; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D047493:PPAR alpha / Q000235:genetics; D047495:PPAR gamma / Q000235:genetics; D010739:Phospholipase D / Q000235:genetics; D010802:Phylogeny; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases; D043884:Receptor, Cannabinoid, CB1 / Q000235:genetics; D043885:Receptor, Cannabinoid, CB2 / Q000235:genetics; D000074025:TRPA1 Cation Channel; D050916:TRPV Cation Channels; D050051:Transient Receptor Potential Channels / Q000235:genetics; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics*; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D015220:Calcium Channels; D063385:Cannabinoid Receptor Modulators; D051546:Cyclooxygenase 2; D063388:Endocannabinoids; D008071:Lipoprotein Lipase; D009419:Nerve Tissue Proteins; D047493:PPAR alpha; D047495:PPAR gamma; D010739:Phospholipase D; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; D017027:Protein Tyrosine Phosphatases; D043884:Receptor, Cannabinoid, CB1; D043885:Receptor, Cannabinoid, CB2; D000074025:TRPA1 Cation Channel; D050916:TRPV Cation Channels; D050051:Transient Receptor Potential Channels; D029961:Zebrafish Proteins; D000099252:Fatty Acid Amide Hydrolases; C473350:TRPA1 protein, human; C494482:TRPV1 protein, human; C416986:TRPV4 protein, human; C496540:PTGS2 protein, human; C480280:DAGLA protein, human; C480281:DAGLB protein, human; C516765:PTPN22 protein, human; C516766:Ptpn22 protein, mouse; C506062:Napepld protein, mouse; C516565:FAAH2 protein, human; C523108:NAAA protein, human