EFFECT OF GLUCOCORTICOIDS ON PIT 1 INHIBITION OF SV40 ENHANCER ACTIVITY

Document Type : Original Article

Authors

Department of Biochemistry Faculty of Medicine AL-Fateh University Tripoli, S.P.L.A.J

Abstract

Earlier studies had shown an effect of glucocorticoids receptor on Pit 1 activation of rPrl promoter activity Treacy. Therefore, the effect of glucocorticoids on Pit 1 inhibition of SV40 enhancer function was investigated in a series of co-transfection studies into glucocorticoids receptor deficient CV-1 cells. Under identical conditions co-transfection of CMV – Pit 1 activated transcription from prPrl (-1960-+38) – CAT; however, expression of GR in the presence of dexamethasone (10-6M) suppressed this activation. The effect of glucocorticoids on the inhibition of SV40 enhancer activity by Pit 1 was investigated. In co- transfection studies in CV-1 cells (Figure 4) it was shown that GR expression and the provision of glucocorticoids (dexamethasone 10-6M) blocked the ability of Pit 1 to inhibit SV40 enhancer activity. Under the same conditions the ability of Pit 1 to activate the rPrl promoter (-1960/+38) was inhibited.