title: Two inducible, functional cyclooxygenase-2 genes are present in the rainbow trout genome.
abstract: The cyclooxygenases (Cox) catalyze the initial reactions in prostanoid biosynthesis, and produce the common prostanoids precursor, PGH(2). Mammalian species have two Cox isoforms; constitutively expressed cyclooxygenase-1 (Cox-1) and inducible cyclooxygenase-2 (Cox-2). Database searches suggest three Cox genes are present in many fish species. In this study, we cloned and characterized a second Cox-2 cDNA, Cox-2b, from the rainbow trout. Rainbow trout Cox-2b protein contains all the functionally important conserved amino acids for Cox enzyme activity. Moreover, the Cox-2b message contains AU-rich elements (AREs) in the 3' untranslated region (3'UTR) characteristic of inducible Cox-2 mRNAs. We took advantage of the existence of a rainbow trout cell line to demonstrate that expression from both the originally reported Cox-2 (Cox-2a) and Cox-2b genes is inducible. However, differential induction responses to alternative inducers are observed for rainbow trout Cox-2a and Cox-2b. Both Cox-2a and Cox-2b proteins expressed in COS cells are enzymatically active. Thus the rainbow trout has two functional, inducible Cox-2 genes. The zebrafish also contains two Cox-2 genes. However, genome structure analysis suggests diversion of the Cox-2a gene between zebrafish and rainbow trout.
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA.
authors.forename: Tomo-o
authors.initials: TO
authors.lastname: Ishikawa
authors.forename: Harvey R
authors.initials: HR
authors.lastname: Herschman
mesh_terms: D020413:3' Untranslated Regions; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D019556:COS Cells; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D017124:Conserved Sequence; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004790:Enzyme Induction; D005091:Exons; D014644:Genetic Variation; D016678:Genome; D007438:Introns; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics*; D016366:Open Reading Frames; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D020413:3' Untranslated Regions; D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; D051546:Cyclooxygenase 2