REGULATION OF A PROMOTER FROM THE MOUSE INSULIN-LIKE-GROWTH-FACTOR-IIGENE BY GLUCOCORTICOIDS

We have microinjected constructs containing the murine IG II P3 promot er linked to different flanking sequences and a luciferase reporter ge ne into mouse pronuclei to establish transgenic lines of mice. The off spring was used as a source of embryonic fibroblast cultures and the e ffect of exogenous addition of glucocorticoids on transgene expression was analysed. It was found that both dexamethasone and hydrocortisone gave rise to a functional stimulation of the IGF II P3 promoter when the construct also contained other elements. This study demonstrates f or the first time that there is an effect of glucocorticoids on the ac tivation of an embryonic IGF II promoter, thus providing a molecular r ationale for previous findings that glucocorticoids can under certain circumstances give rise to an increased transcriptional activity of th e IGF II gene. (C) 1997 Federation of European Biochemical Societies.