EVIDENCE THAT PHOSPHATIDYLCHOLINE-SPECIFIC PHOSPHOLIPASE-C IS A KEY MOLECULE MEDIATING INSULIN-INDUCED ENHANCEMENT OF GENE-EXPRESSION FROM HUMAN CYTOMEGALOVIRUS PROMOTER IN CHO CELLS

The signal transduction from insulin to its receptors and Ras has been extensively studied, while little has been reported beyond these step s. We found that the expression of human interleukin 6 gene under the control of immediate early gene promoter of human cytomegalovirus was enhanced by insulin sitmulation in Chinese hamster ovary cells. The in duction effect of insulin was not significantly affected by inhibitors or activators of conventional protein kinase C, cAMP dependent protei n kinase and phosphoinositide -3 kinase, however, pre-incubation of th e cells with D609, a specific inhibitors of phosphatidylcholine-specif ic phospholipase C completely abolished the induction effect. These re sults clearly demonstrate that phosphatidylcholine-specific phospholip ase C is a key molecule mediating insulin-induced enhancement of hIL-6 expression from the human cytomegalovirus promoter in Chinese hamster ovary cells and strongly suggest that it plays an important role in t he insulin signaling pathways.