Roles of bromodomain in the regulation of p300-dependent gene expression

Abstract

The transcriptional coactivator p300 displays an intrinsic histone acetyltransferase activity. It contains an evolutionarily conserved bromodomain serving as a specific acelyl-lysine binding module for histones or transcription factors to facilitate chromatin remodeling and transcriptional activation. The function of p300 is required by a diverse set of promoters. However, roles of bromodomain in the function of p300 are yet to be fully determined. In this study, we utilize cell lines expressing either wild-type or bromodomain truncated p300 to examine the expression of several p300-dependent genes that are involved in cell cycle regulation. The effects of histone acetylation on the expression of these genes were also examined by utilizing histone deacetylase inhibitors. Our results suggest that p300 regulates genes through different mechanisms and that bromodomain has roles in the recruitment of p300 to target promoters, providing an indication that the role of bromodomain in p300-dependent transcription is determined by individual promoter context.