Renin gene expression, biosynthesis, and cellular pathways of secretion.

The molecular biology of the human renin gene is reviewed. This 12.5 kb gene contains 10 exons and 9 introns. In its 5' flanking region, major control elements are present. These include promoters and enhancers as well as regulatory elements. The combined action of these elements would result in tissue specific expression and regulation of the gene. In addition to the control at the gene expression level, renin is also regulated at the posttranslational and secretory levels. The translational product of renin mRNA is preprorenin, which is cotranslationally cleaved to prorenin, an inactive precursor of renin. The majority of new synthesized human prorenin is constitutively secreted. However, prorenin is also processed intracellularly to the mature single chain active renin which is stored in secretory granules. Active renin is released by a regulated mechanism which can be stimulated by cAMP and other secretagogues. Studies are under way to examine the responses of renin gene expression, biosynthesis and secretion to various physiological conditions.