| Research Abstract |
1.(1) The organization and primary structure of the gene coding for human vasoactive intestinal peptide (VIP) were determined. (2) The VIP gene was assigned to q26->27 of human chromosome 6. (3) The VIP gene expression was found to be induced by cyclic AMP and phorbol esters, and cisacting DNA hements and a transacting nuclear factor that mediate the induction were identified. (4) Peptidylglycine alpha-amidating sonooxygenase, an enzyme involved in the final step of VIP biosynthesis, was purified from rat brain and equine serum, and an intermediate of the alpha-amidating reaction was identified. (5) Structural analyses of the cDNA and the gene for pancreatic polypeptide, another carboxyamidated peptide, revealed that the blend of conservation and divergence in the polypeptide precursor has been generated through "mosaic evolution" of the gene.
2.(1) A novil gene encoding a 145-amino acid protein was identified in screening a rat insulinona-derived cDNA library, and designated rig (rat i
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nsulinona gene). (2) rig was found to be expressed at high levels in a variety of human tumors, including insulinomas, and also in proliferating normal cells. (3) The organization and structure of human genomic rig and its pseudogenes were determined. (4) The rig protein was found to accumulate in the nucleus at the S phase of the cell cycle, and the DNA synthesis in insulinona cells was inhibited by microinjection of antisense oligonucleotides complementary to rig mRNA, indicating that rig may be involved in cell growth and replication. (5) In screening a rat regenerating islet-derived cDNA library, a novel gene, reg (regenerating gene), was identified: reg encoded a 165-amino acid secretory protein and was expressed during the regeneration of insulin-producing beta-cells. (6) The human reg cDNA and gene were also isolated and their complete nucleotide sequences were determined. (7) The rig and reg genes were built into expression vectors to drive Escherichia coli and yeast to synthesize rig and reg proteins. The higher-order structure of the recombinant reg protein was characterized. Less
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