SHORT GLUCOCORTICOID-RESPONSIVE ELEMENT IN THE 5'-FLANKING REGION OF MURINE METALLOTHIONEIN-I GENE

Transient gene transfer experiments on murine LTK cells revealed a glu cocorticoid-responsive element (GRE) in the near 5'-flanking region (- 252/-209) of the murine metallothionein I gene (mMTI). When inserted b efore a heterologous HSV TK gene promoter, it was capable of enhancing in an orientation-independent manner the expression of the reporter C AT gene in response to dexamethasone; its duplication additionally pot entiated CAT induction. However, the natural mMTI promoter region (-33 0/+70) containing the GRE failed to provide glucocorticoid induction o f a linked CAT gene, while the regulation by heavy metal ions was reta ined at a level comparable to that in vivo.