REGULATION OF GENE-EXPRESSION BY INSULIN

While insulin has long been known to modulate intracellular metabolism by altering the activity or intracellular location of various enzymes , it is only in the past 10 years that the regulation of gene expressi on by insulin has been recognized as a major action of this hormone. T his review principally focuses on the regulation of gene transcription by insulin, although recent progress in the understanding of insulin- regulated mRNA stability and translation is also summarized. The ident ification of cis-acting elements and associated trans-acting factors t hrough which insulin either increases or decreases the transcription o f specific genes is reviewed in detail. Recent advances in the underst anding of the mechanisms of insulin signaling are discussed in the con text of insulin-regulated gene transcription, and emphasis is placed o n the gaps that remain between the upstream signaling molecules and th e downstream trans-acting factors whose binding/transactivation potent ial is ultimately regulated. Finally, potential gene expression defect s that may contribute to the pathophysiology of non-insulin-dependent diabetes mellitus and hypertriglyceridemia are considered.