Cloning and characterization of porcine insulin gene.

The complete porcine preproinsulin cDNA and 1022 bp of its 5'-flanking region have been cloned by PCR-based technology and characterized. The porcine insulin gene has the same structure of three exons and two introns as that found in all insulin genes sequenced to date. Northern blot analysis of isolated adult porcine islets demonstrated an increase in steady-state insulin mRNA levels in response to high concentrations of glucose. Highly conserved cis-acting elements were found in the 5'-flanking region of the porcine insulin gene including multiple E and A elements as well as a cAMP responsive element (CRE). Tissue-specific activity of the proximal promoter was confirmed by transient transfection of the promoter/reporter gene constructs. This information now makes it possible for regulation and expression of the porcine insulin gene to be analyzed.