title: Sequence of a cDNA encoding pancreatic preprosomatostatin-22.
abstract: We report the nucleotide sequence of a precursor to somatostatin that upon proteolytic processing may give rise to a hormone of 22 amino acids. The nucleotide sequence of a cDNA from the channel catfish (Ictalurus punctatus) encodes a precursor to somatostatin that is 105 amino acids (Mr, 11,500). The cDNA coding for somatostatin-22 consists of 36 nucleotides in the 5' untranslated region, 315 nucleotides that code for the precursor to somatostatin-22, 269 nucleotides at the 3' untranslated region, and a variable length of poly(A). The putative preprohormone contains a sequence of hydrophobic amino acids at the amino terminus that has the properties of a "signal" peptide. A connecting sequence of approximately 57 amino acids is followed by a single Arg-Arg sequence, which immediately precedes the hormone. Somatostatin-22 is homologous to somatostatin-14 in 7 of the 14 amino acids, including the Phe-Trp-Lys sequence. Hybridization selection of mRNA, followed by its translation in a wheat germ cell-free system, resulted in the synthesis of a single polypeptide having a molecular weight of approximately 10,000 as estimated on Na-DodSO4/polyacrylamide gels.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D005399:Fishes; D005796:Genes; D009693:Nucleic Acid Hybridization; D010179:Pancreas / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000235:genetics
chemical_list: D011498:Protein Precursors; D012333:RNA, Messenger; D013004:Somatostatin; D004247:DNA