Regulation of a promoter from the mouse insulin like growth factor II gene by glucocorticoids

We have microinjected constructs containing the murine IG II P3 promoter linked to different flanking sequences and a luciferase reporter gene into mouse pronuclei to establish transgenic lines of mice. The offspring was used as a source of embryonic fibroblast cultures and the effect 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 for the first time that there is an effect of glucocorticoids on the activation of an embryonic IGF II promoter, thus providing a molecular rationale for previous findings that glucocorticoids can under certain circumstances give rise to an increased transcriptional activity of the IGF II gene.