The Novel ReNu Region of TAF12 Regulates Gcn5 Nucleosomal Acetylation.

The post-translational acetylation of the histone components of chromatin mediates numerous DNA-templated events, including transcriptional activation, DNA repair, and genomic replication. The conserved SAGA (Spt-Ada-Gcn5 Acetyltranferase) and SLIK (SAGA-Like) Histone Acetyltransferase (HAT) complexes are required for transcriptional activation of a subset of yeast genes and contain multiple subunits including the histone fold-containing TBP- Associated Factors (TAFs): 6, 9, 10, and 12. These TAFs are also components of the TFIID complex and are consequently involved in most RNA polymerase II-transcription in yeast. Here we identify a novel conserved region of TAF12, termed ReNu, outside of its histone fold, which is required for SAGA and SLIK-directed nucleosomal acetylation. We demonstrate that this region is not required for chromatin association, but show that this region plays an important role for histone H3 acetylation at specific SAGA and SLIK-regulated promoters. Our data suggests that the ReNu region of TAF12 regulates Gcn5 acetylation of specific substrates within the SAGA super-family of HAT complexes.