Project description:The SCH9 null strain has smaller cell size, grows at a slower rate and survives three times longer than wide-type yeast. This study aims to dissect the mechanisms that lead to the yeast life span extension of sch9-delta. We measure gene expression profiles of the S. cerevisiae wild type and the long-lived sch9∆ strain every 12 hours from 12 to 120 hours. At each time point, one sample is hybridized to one Affymetrix GeneChip Yeast 2.0 array. In total, ten time points are measured for each strain. When we perform a check of the data quality, all arrays look normal except the 120-hour sch9∆ array. Thus we abandon this array in the further data analysis.
Project description:We report the application of DHS-Seq and digital genomic footprinting to study chromatin changes and transcription factor-DNA binding upon long-term Hsp90 depletion utilizing the temperature-sensitive allele G170D. By generating about 86 and 85.6 million reads for wild type and mutant, we were able to reconstitute the chromatin accessibility and the transcription factor-DNA binding maps under regular conditions and under conditions where Hsp90 was long-term inactivated. We find that there is a global reduction of transcription factor binding sites with concurrent loss of open chromatin upon Hsp90 inactivation. This data was used in conjunction with our previous work involving DHS-Seq studies and short-term Hsp90 depletion (GEO GSE88875) to distinguish the affected transcription factor networks and the chromatin changes upon short- and long-term Hsp90 depletion. We identified two different modes of Hsp90 operation on transcription factor activities – short-term inactivation of Hsp90 altered transcription factor DNA binding activities, whereas long-term Hsp90 inactivation affected the steady-state levels of transcription factors. Overall, this study shows that Hsp90 regulates multiple transcription factor protein families and modulates chromatin architecture on a genome-wide scale.
