Exons of the human pancreatic polypeptide gene define functional domains of the precursor.

摘要: Abstract Pancreatic polypeptide is a 36-amino acid peptide which inhibits pancreatic exocrine function. We have previously determined from the nucleotide sequence of cDNA that derived 95-amino precursor, prepropancreatic polypeptide. Pulse-chase studies suggested precursor cleaved to produce three peptides: polypeptide, an icosapeptide, and smaller peptide. In present study, we used cloned as hybridization probe isolate gene human bacteriophage genomic library. The 2.8 kilobases DNA representing entire was determined. contains four exons introns. Exon 1 encodes 5'-untranslated region mRNA, exon 2 signal 3 4 carboxyl-terminal heptapeptide 3'-untranslated mRNA. By Southern blot analysis, detected in polypeptide-producing islet cell tumor indistinguishable normal leukocytes. structure consistent with hypothesis generates distinct peptides, each encoded by separate exon. Increased expression does not appear be correlated major alterations structure.