Project description:Evidence suggests that the TAF1 subunit of TFIID is a histone acetyltransferase (HAT) that is functionally redundant with the Gcn5 HAT of the SAGA and ADA complexes. Here we test a number of predictions of this hypothesis by examining the in vivo histone acetylation targets of TAF1 and Gcn5, and re-examining the basis for the reported genome-wide functional redundancy between TAF1 and Gcn5. Our findings do not support a number of basic tenets of the hypothesis, thus bringing into question the physiological presence of any TAF1 HAT function in yeast. We have also conducted genome-wide expression profiles of numerous other HATs (Elp3, Hat1, Hpa2, Sas3) in an effort identify potential functional redundancy between TAF1 and other HATs, and find none. Further investigation of TAF1 and the Esa1 HAT re-affirm a link between histone H4 acetylation by Esa1, and TFIID binding via interactions with acetylated histone H4-binding protein Bdf1. Keywords: ChIP-chip, genetic modification
Project description:Evidence suggests that the TAF1 subunit of TFIID is a histone acetyltransferase (HAT) that is functionally redundant with the Gcn5 HAT of the SAGA and ADA complexes. Here we test a number of predictions of this hypothesis by examining the in vivo histone acetylation targets of TAF1 and Gcn5, and re-examining the basis for the reported genome-wide functional redundancy between TAF1 and Gcn5. Our findings do not support a number of basic tenets of the hypothesis, thus bringing into question the physiological presence of any TAF1 HAT function in yeast. We have also conducted genome-wide expression profiles of numerous other HATs (Elp3, Hat1, Hpa2, Sas3) in an effort identify potential functional redundancy between TAF1 and other HATs, and find none. Further investigation of TAF1 and the Esa1 HAT re-affirm a link between histone H4 acetylation by Esa1, and TFIID binding via interactions with acetylated histone H4-binding protein Bdf1. Keywords: genetic modification
Project description:We have investigated the genome-wide occupancy of Sas3p by ChIP-Chip, using tiled microarrays. Using this technique, it has been described that H3K14 and H3K9 acetylation is enriched at promoter regions and transcriptional start sites of active genes. Considering that Sas3p is a HAT whose main target in vitro is H3K14 we expected to detect Sas3 binding largely to promoter regions of genes. Surprisingly, we found that Sas3p is associated to the coding regions of genes, with a peak enrichment located) within the 5’ half of the ORF, and this enrichment drops substantially toward the 3’ region of the ORF. This result is very similar to that obtained for Yng1 genome-wide occupancy, also a component of the NuA3 complex, suggesting that this complex could be involved in transcriptional elongation, at least, in an initial step of the process.
