title: Characterization of two duplicate zebrafish Cb2-like cannabinoid receptors.
abstract: Several cannabinoid receptors have been detected in many organisms. The best known are CB1, mainly expressed in the central nervous system and CB2 which is almost exclusively expressed in the periphery. Here we report the molecular characterization of two duplicate CB2-like cannabinoid receptors from zebrafish (Danio rerio) (zebrafish Cb2a and zebrafish Cb2b). The amino acid sequences of these receptors present 56% identity with Takifugu rubripes CB2 sequence and 39% with human CB2 sequence and conserve some specific key residues for cannabinoid receptor function. Both duplicate receptors are expressed in peripheral tissues (gills, heart, intestine and muscle), immune tissue (spleen) and also in the central nervous system. Using in situ hybridization techniques zebrafish Cb2 mRNA expression was observed for the first time in the adenohypophysial cells of the rostral pars distalis and proximal pars distalis of the pituitary gland. Given the importance of the existence of duplication of genes in teleosts, the combined analysis of these two new cannabinoid receptors opens a new exciting door to investigate and understand cannabinoid function throughout evolution.
authors.affiliation: Faculty of Medicine, Department of Biochemistry and Molecular Biology, University of Salamanca, Spain; Instituto de Neurociencias de Castilla y Leon (INCYL), Spain.
authors.forename: I
authors.initials: I
authors.lastname: Rodriguez-Martin
authors.forename: M J
authors.initials: MJ
authors.lastname: Herrero-Turrion
authors.forename: E
authors.initials: E
authors.lastname: Marron Fdez de Velasco
authors.forename: R
authors.initials: R
authors.lastname: Gonzalez-Sarmiento
authors.forename: R E
authors.initials: RE
authors.lastname: Rodriguez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000166:cytology; D002875:Chromosomes; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D020131:Genes, Duplicate / Q000235:genetics*; D016678:Genome; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043885:Receptor, Cannabinoid, CB2 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D043882:Receptors, Cannabinoid / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: C518179:Cnr2 protein, zebrafish; D012333:RNA, Messenger; D043885:Receptor, Cannabinoid, CB2; D043882:Receptors, Cannabinoid; D029961:Zebrafish Proteins