Cloned cDNA to cholecystokinin mRNA predicts an identical preprocholecystokinin in pig brain and gut.

Abstract

Molecular cloning has established the structure of preprocholecystokinin in porcine cerebral cortex and duodenal mucosa. This precursor is 114 amino acids long, is identical in brain and gut, contains all the cholecystokinin (CCK) peptides previously isolated, and has the characteristics of a prohormone. It contains a putative amino-terminal signal peptide, basic processing sites and a carboxyl-terminal amidation signal. The CCK mRNA from brain and gut are .apprxeq. 850 nucleotides long and differ by only a few single base changes. This analysis establishes by a strict criterion that CCK is synthesized in both brain and gut and that the different distributions of molecular forms of CCK in the 2 tissues are most probably a consequence of tissue-specific posttranslational events.