Molecular Cloning of Human Gastrin cDNA: Evidence for Evolution of Gastrin by Gene Duplication

• Published in: Proceedings of the National Academy of Sciences - PNAS 1983-01, Vol.80 (10), p.2866-2869
• Main Authors: Boel, Esper, Vuust, Jens, Norris, Fanny, Norris, Kjeld, Wind, Anette, Rehfeld, Jens F., Marcker, Kjeld A.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Base Sequence; Biological Evolution; Cloning, Molecular; Complementary DNA; DNA; DNA - genetics; Gastrinoma; Gastrins - genetics; Generally accepted auditing standards; Gin; Humans; Messenger RNA; Nucleotides; RNA; Untranslated regions
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.80.10.2866

An oligo(dT)-primed cDNA copy of the mRNA coding for the human gastrin precursor was constructed from poly(A)-containing RNA from a human pancreatic, gastrin-producing tumor (a gastrinoma). The cDNA was inserted into the Pst I endonuclease site of plasmid pBR322 by the use of the poly(dC) and poly(dG) tailing procedure. Clones containing gastrin sequences were selected by hybridization to a purified single-stranded32P-labeled gastrin cDNA probe. This probe was constructed with gastrinoma mRNA as template. As primer for the cDNA synthesis, we used a synthetic oligonucleotide mixture, d(G A-A-A-G A-T-C-C-A-T-C-C-A), corresponding to the gastrin-specific amino acid sequence Trp-Met-Asp-Phe. In this way we determined the nucleotide sequence of the entire coding region (303 nucleotides), the entire 3′untranslated region (102 nucleotides), and 8 nucleotides of the 5′untranslated region. A striking homology between parts of the coding region suggests that evolution of the gastrin gene has involved a gene duplication.