Coordinate regulation of yeast ribosomal protein genes is associated with targeted recruitment of Esa1 histone acetylase

The Esa1-containing NuA4 histone acetylase complex can interact with activa tion domains in vitro and stimulate transcription on reconstituted chromati n templates. In yeast cells, Esa1 is targeted to a small subset of promoter s in an activator-specific manner. Esa1 is specifically recruited to riboso mal protein (HP) promoters, and this recruitment appears to require binding by Rap1 or Abf1. Esa1 is important for RP transcription, and Esa1 recruitm ent to RP promoters correlates with coordinate regulation of RP genes in re sponse to growth stimuli. However, following Esa1 depletion, H4 acetylation decreases dramatically at many loci, but transcription is not generally af fected. Therefore, the transcription-associated targeted recruitment of Esa 1 to RP promoters occurs in a background of more global nontargeted acetyla tion that is itself not required for transcription.