The role of the central region of Ada2 in gene regulation

The SAGA complex of Saccharomyces cerevisiae contains greater than 20 components that acetylate and deubiquitylate nucleosomal histones. Its acetyltransferase, Gcn5 preferentially acetylates histones H3 and H2B and is regulated through interactions with Ada2 and Ngg1/Ada3. The N-terminal region of Ada2 contains a SANT domain that contacts Gcn5 near its catalytic site. Sequence alignments of Ada2 homologues indicate a conserved ~120 amino acid residue central region that interacts with Ngg1.To examine the function of this central region, we constructed ada2 alleles with mutations of clustered conserved residues. One of these alleles, ada2-RLR, resulted in a ~3-fold reduction in transcriptional activation of the PHO5 gene and growth changes that parallel deletion of ada2. Microarray analyses further revealed that ada2-RLR alters expression of a subset of those genes affected by deletion of ada2. Keywords: yeast, Ada2, SAGA complex, gene expression, genetic modification Three dye-swapped, biological replicate experiments were performed for BY4842 (ada2delta) with reference to BY4741 (wt). Similarly, in the BY4842 (ada2delta) strain background three dye-swapped, biological replicate experiments were performed for a strain expressing a mutant ada2 allele from a plasmid with reference to a strain expressing wild-type ada2 from a plasmid.