Primary structure of the gene encoding rat preprosomatostatin.

Abstract

Somatostatins are peptides of 14 and 28 amino acids that are produced in a variety of endocrine and nonendocrine tissues. These peptides inhibit the secretion of many different pituitary, pancreatic and gastrointestinal hormones. Isolation and nucleotide sequence was previously reported of a c[complementary]DNA derived from a rat medullary thyroid carcinoma that encoded preprosomatostatin, a 116-amino-acid precursor of somatostatin. Here the structural characterization of the rat somatostatin gene isolated from recombinant bacteriophage libraries prepared from rat liver DNA is reported. The gene spans 1.2 kilobases and is interrupted within the coding sequence of prosomatostatin by a single intron of 630 bases. A sequence characteristic of a Goldberg-Hogness promoter (TATA box), T-T-T-A-A-A-A, is located 31 bases upstream from the transcriptional initiation site. A repetitive DNA sequence, highly reiterated in the rat genome, is located in the 5'' flanking region of the gene within 900 bases of the initiation site.