Stimulation of NF-E2 DNA binding by CREB-binding protein (CBP)-mediated acetylation

The hematopoietic transcription factor NF-E2 is an important regulator of e rythroid and megakaryocytic gene expression, The transcription cofactor cAM P-response element-binding protein (CREB)-binding protein (CEP) has previou sly been implicated in mediating NF-E2 function. In this report, we examine d the role of CBP, a coactivator with intrinsic acetyltransferase activity, in the regulation of NF-E2, We found that both the hematopoietic-specific subunit of NF-E2, p45, and the widely expressed small subunit, MafG, intera ct with CBP in vitro and in vivo. CBP acetylates MafG;, but not p45, predom inantly in the basic region of MafG. Immunoprecipitation experiments with a nti acetyl lysine antibodies demonstrate that MafG is acetylated in vivo in erythroid cells. Transfection experiments further show that CBP stimulates MafG acetylation in intact cells in an E1A sensitive manner. Acetylation o f MafG augments DNA binding activity of NF-E2, and mutations at the major a cetylation sites markedly reduce DNA binding and transcriptional activation by NF-E2. Together, these results suggest that recruitment of CBP by NF-E2 to specific erythroid/megakaryocytic promoters might regulate transcriptio n by at least two mechanisms involving both modification of chromatin struc ture and modulation of transcription factor activity.