EXPRESSION AND CHARACTERIZATION OF A FUSION PROTEIN BETWEEN THE CATALYTIC DOMAIN OF POLY(ADP-RIBOSE) POLYMERASE AND THE DNA-BINDING DOMAIN OF THE GLUCOCORTICOID RECEPTOR

A fusion protein comprising the DNA-binding region of the glucocortico id receptor and the catalytic domain of poly(ADP-ribose) polymerase wa s constructed. This chimeric protein was expressed both in E. coli and in eukaryotic cells and was recognized by antibodies to both polymera se and the glucocorticoid receptor. Similar to polymerase, the chimera produced bona fide poly (ADP-ribose) polymers covalently bound to pro tein and was inhibited by 3-aminobenzamide. Like the authentic glucoco rticoid receptor, the fusion protein formed a stable complex with DNA containing the glucocorticoid response element. In mammalian cells, th e fusion protein significantly and specifically inhibited the ability of the glucocorticoid receptor to stimulate a reporter construct. Thes e results indicate that polymerase activity can be targeted to specifi c DNA sequences and modulate gene expression. (C) 1994 Academic Press, Inc.