title: Two isotocin genes are present in the white sucker Catostomus commersoni both lacking introns in their protein coding regions.
abstract: Two genes each encoding a distinct precursor protein to the hormone isotocin and a neurophysin-related protein are present in the teleost fish Catostomus commersoni. These precursors are referred to as isotocin 1 and 2. As shown by the polymerase chain reaction technique, both genes lack introns in their protein-coding sequences. Both genes are transcribed giving rise to mRNAs of 920 (isotocin 1) and 1020 (isotocin 2) bases, respectively. Based on the nucleotide sequences, the predicted isotocin precursors contain, besides the hormone moiety, a neurophysin-like protein that, in contrast to its mammalian counterpart, is extended at its C-terminus by a peptide which includes a leucine-rich core segment. This segment shows similarities to the copeptin of the mammalian vasopressin precursor that is known to possess prolactin-releasing activity. The data imply that the mammalian copeptin sequence was initially part of a larger ancestral neurophysin molecule.
authors.affiliation: Institut für Zellbiochemie und Klinische Neurobiologie, Universitäts-Krankenhaus Eppendorf, Hamburg, FRG.
authors.forename: J
authors.initials: J
authors.lastname: Figueroa
authors.forename: S D
authors.initials: SD
authors.lastname: Morley
authors.forename: J
authors.initials: J
authors.lastname: Heierhorst
authors.forename: C
authors.initials: C
authors.lastname: Krentler
authors.forename: K
authors.initials: K
authors.lastname: Lederis
authors.forename: D
authors.initials: D
authors.lastname: Richter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D003531:Cypriniformes / Q000235:genetics*; D004247:DNA / Q000235:genetics; D005091:Exons; D005796:Genes; D007438:Introns; D008969:Molecular Sequence Data; D009481:Neurophysins / Q000235:genetics; D010121:Oxytocin / Q000235:genetics / Q000031:analogs & derivatives; D016133:Polymerase Chain Reaction; D011498:Protein Precursors / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014667:Vasopressins / Q000235:genetics
chemical_list: D009481:Neurophysins; D011498:Protein Precursors; D014667:Vasopressins; D010121:Oxytocin; C008215:isotocin; D004247:DNA