title: Molecular cloning and characterization of preproorexin in winter skate (Leucoraja ocellata).
abstract: A 815 base pairs (bp) cDNA encoding for preproorexin (preproOX) was cloned in winter skate, a cartilaginous fish. Winter skate preproOX is 159 amino acids (aa) long and contains a 34 aa orexin A and 28 aa orexin B. The amino acid sequence of winter skate preproOX is more similar to tetrapod preproOXs (36-40% identity) than teleost preproOXs (23-33% identity). Whereas orexin B appears relatively well conserved among vertebrates, orexin A displays more variability, in particular due to an "insertion sequence" that is present in teleost fish, but not in skate and tetrapods. RT-PCR studies show that preproOX mRNA has a widespread distribution within the brain and is present in several peripheral tissues, including gastrointestinal tract, heart and testes. Fasting induced increases in preproOX expression in the hypothalamus, suggesting that orexin might play a role in the regulation of food intake in winter skate.
authors.affiliation: Department of Biology, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X9.
authors.forename: Erin E
authors.initials: EE
authors.lastname: MacDonald
authors.forename: Hélène
authors.initials: H
authors.lastname: Volkoff
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004435:Eating; D005215:Fasting; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D000068797:Orexins; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012860:Skates, Fish / Q000235:genetics*; D014018:Tissue Distribution
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D011498:Protein Precursors; D012333:RNA, Messenger