title: Retina-specifically expressed novel subtypes of bovine cyclophilin.
abstract: The Drosophila ninaA gene encodes photoreceptor-specific cyclophilin thought to play a critical role in rhodopsin folding or transport during its synthesis or maturation in the most abundant subclass of photoreceptors. Cyclophilins comprise a highly conserved family of proteins which are the primary targets of the potent immunosuppressive drug, cyclosporin A (CsA), and which display peptidyl prolyl cis-trans-isomerase (PPIase) activity. In an attempt to identify mammalian cyclophilins with properties similar to the NinaA protein, a probe derived from the ninaA cDNA was used to screen bovine retina cDNA libraries. The screen identified two major alternatively spliced forms of cDNA that would encode proteins containing a region of high homology to other cyclophilins and that are expressed specifically in the retina. These proteins represent a new class of cyclophilins with novel structural features and greatly reduced PPIase and CsA binding activities in comparison to other known cyclophilins. Tissue in situ hybridization and immunolocalization of the proteins showed that the RNA and protein products are expressed in photoreceptors as well s other retinal neurons. However, among photoreceptors, the proteins are found predominantly in cones. Thus, mammalian retinas do contain cyclophilins that are retina-specifically and photoreceptor class-preferentially expressed. The results suggest that, in cones, the main function of these proteins is, like the NinaA protein, to facilitate proper folding or intracellular transport of opsins.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Ferreira
authors.forename: J T
authors.initials: JT
authors.lastname: Hom
authors.forename: W L
authors.initials: WL
authors.lastname: Pak
mesh_terms: D017398:Alternative Splicing; D000591:Amino Acid Isomerases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D018833:Chaperonins / Q000096:biosynthesis; D003001:Cloning, Molecular; D003524:Cyclosporins / Q000378:metabolism; D018076:DNA, Complementary; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins; D015870:Gene Expression; D015723:Gene Library; D017344:Genes, Insect; D006801:Humans; D017403:In Situ Hybridization; D007301:Insect Hormones / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D007700:Kinetics; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D018832:Molecular Chaperones; D008969:Molecular Sequence Data; D009928:Organ Specificity; D019696:Peptidylprolyl Isomerase; D012160:Retina / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism; D012374:Rod Cell Outer Segment / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D003524:Cyclosporins; D018076:DNA, Complementary; D029721:Drosophila Proteins; D007301:Insect Hormones; D008565:Membrane Proteins; D018832:Molecular Chaperones; C068480:ninaA protein, Drosophila; D018833:Chaperonins; D000591:Amino Acid Isomerases; D019696:Peptidylprolyl Isomerase