title: In vivo and in vitro expression of a non-mammalian cyclooxygenase-1.
abstract: Unlike cyclooxygenase 2 (COX-2), COX-1 has never been identified, purified or cloned in a non-mammalian species. Here we report the RT-PCR cloning of a chicken cDNA that encodes the amphipathic membrane binding region and parts of the dimerization and catalytic domains of COX-1-like enzyme. Sequence comparison showed this putative COX-1 to be evolutionarily less conserved than COX-2. Furthermore, whereas COX-1 in mammals is broadly expressed in tissues as a constitutive enzyme, the mRNA detected by our clone in chicken was almost absent in tissues and embryo fibroblasts (CEF). Highest expression was in brain and seminal vesicle. This transcript was not detectable during chick embryogenesis and, as is the case for mammalian COX-1, was not induced above background by mitogen stimulation. The identification of an avian COX-1 shows that COX-1 and COX-2 existed as separate catalysts for prostaglandin synthesis before the divergence of birds and mammals.
authors.affiliation: Department of Zoology, Brigham Young University, Provo, UT 84602, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Reed
authors.forename: W S
authors.initials: WS
authors.lastname: Bradshaw
authors.forename: W
authors.initials: W
authors.lastname: Xie
authors.forename: D L
authors.initials: DL
authors.lastname: Simmons
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002642:Chick Embryo; D002645:Chickens; D003001:Cloning, Molecular; D017124:Conserved Sequence; D051545:Cyclooxygenase 1; D017931:DNA Primers; D019143:Evolution, Molecular; D005786:Gene Expression Regulation / Q000235:genetics*; D015723:Gene Library; D006706:Homeostasis / Q000502:physiology; D007527:Isoenzymes / Q000737:chemistry*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D017931:DNA Primers; D007527:Isoenzymes; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D011451:Prostaglandin-Endoperoxide Synthases