Multivalent Binding of p53 to the STAGA Complex Mediates Coactivator Recruitment after UV Damage

Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, New York 10021

^* To whom correspondence should be addressed. Email: roeder{at}mail.rockefeller.edu.

	Abstract

The recruitment of transcriptional coactivators, including histone modifying enzymes, is an important step in transcription regulation. A typical activator is thought to interact with several cofactors, presumably in a sequential manner. The common use of several cofactors raises the question of how activators achieve both cofactor selectivity and diversity. Human STAGA is a multiprotein complex with the acetyltransferase GCN5L as the catalytic subunit. Here we first show, through RNAi-mediated knock down and chromatin immunoprecipitation assays, that GCN5 plays a role in p53-dependent gene activation. We then employ p53 mutagenesis, in vitro binding, protein-protein crosslinking, and chromatin immunoprecipitation assays to establish a novel role for the second p53 activation subdomain (AD2) in STAGA recruitment and, further, that optimal binding of STAGA to p53 involves interactions of STAGA subunits TAF9, GCN5 and ADA2b, respectively, with AD1, AD2 and carboxy terminal domains of p53. These results provide concrete evidence for mediation of transcription factor binding to coactivator complexes through multiple interactions. Based on our data we propose a cooperative and modular binding mode for the recruitment of coactivator complexes to promoters.