Novel splice variant of mouse insulin2 mRNA: implications for insulin expression.

Insulin is a secreted peptide that controls glucose homeostasis in mammals, and insulin biosynthesis is regulated by glucose at many levels. Rodent insulin is encoded by two non-allelic genes. We have identified a novel splice variant of the insulin2 gene in mice that constitutes about 75% of total insulin2 mRNA. The alternate splicing does not alter the ORF but reduces the 5′UTR by 12 bases. A reporter gene containing the novel short 5′UTR, is more efficiently expressed in cells, suggesting that alternative splicing of insulin mRNA in mice could result in an additional level of regulation in insulin biosynthesis.