Project description:Our data demonstrate binding of NOTCH1 on the promoters of HSF1 and HSF1 targets. We performed RNA-seq upon control conditions, inhibition of the NOTCH1 pathway by gSI, HSF1 knockdown and combination of HSF1 knockdown and gSI treatment. Our results show that NOTCH1 regulates the expression of heat shock response genes. Moreover, combination of HSF1 downregulation and gSI treatment further decreased the expression of heat shock response genes compared to single treatments.
Project description:Heat shock rapidly induces expression of a small set of genes while globally repressing transcription, making it an attractive system for studying alterations in the chromatin landscape that accompany changes in gene regulation. We have characterized these changes using low-salt extraction of intact micrococcal nuclease (MNase)-treated Drosophila S2 cell nuclei to determine the active nucleosomal and subnucleosomal chromatin landscapes. The low-salt-soluble fraction corresponds to classical "active" chromatin and includes distinct size fractions of MNase-protected particles that can be precisely mapped by paired-end sequencing. After heat shock, the distribution of low-salt-soluble nucleosomes showed an overall reduction over gene bodies, consistent with down-regulation of transcription. No global changes were detected in the subnucleosomal landscape upstream of transcriptional start sites, however, we observed a genome-wide reduction of paused RNA Polymerase II from the active chromatin fraction. Furthermore, nucleosome turnover decreased within gene bodies in a pattern similar to that observed when transcription elongation was artificially inhibited. These observations suggest that reduced Pol II affinity and processivity is the dominant nuclear mechanism for genome-wide repression during heat shock. Our ability to precisely map both nucleosomal and subnucleosomal particles directly from classical active chromatin extracts to assay changes in the chromatin landscape provides a simple general strategy for epigenome characterization. High-throughput sequencing (Illumina HiSeq 2000) We have characterized changes to the active nucleosomal and subnucleosomal landscape during the heat shock response in Drosophila cells by genome-wide profiling of low-salt extracted micrococcal nuclease-treated nuclei, paused RNA Polymerase II and CATCH-IT nucleosome turnover.
Project description:RNA polymerase II (Pol II) is generally paused at promoter-proximal regions in most metazoans, and based on in vitro studies, this function has been attributed to the negative elongation factor (NELF). Here, we show that upon rapid depletion of NELF, Pol II fails to be released into gene bodies, stopping instead around the +1 nucleosomal dyad-associated region. The transition to the 2nd pause region is independent of positive transcription elongation factor P-TEFb. During the heat shock response, Pol II is rapidly released from pausing at heat shock induced genes, while most genes are paused and transcriptionally downregulated during the heat shock response. We find that both aspects of the heat shock response remain intact upon NELF loss. We find that NELF depletion results in global loss of cap-binding complex from chromatin without global reduction of nascent transcript 5’ cap stability. Thus, our studies implicate NELF functioning in early elongation complexes distinct from Pol II pause-release.
Project description:In this study, we demonstrate that SH-42 and SH-80, novel heat shock protein 90 inhibitors, suppress retinal neovascularization via inhibition of hypoxia-mediated angiogenesis. To figure out any genotoxic effect of these compounds related with heat shock protein 90 inhibition, we performed microarray analyses with retinal tissues treated with SH-42 and SH-80 for 7 days.
Project description:Whole-genome analysis of heat shock factor binding sites in Drosophila melanogaster. Heat shock factor IP DNA from non-shock (room temperature) Kc 167 cells compared to whole cell extract on Agilent 2x244k tiling arrays.
Project description:Whole-genome analysis of heat shock factor binding sites in Drosophila melanogaster. Heat shock factor IP DNA or Mock IP DNA from heat shocked Kc 167 cells compared to whole cell extract on Agilent 2x244k tiling arrays.
Project description:The WP3 strains was cultured at 20°C and heat shocked at 40°C for 90 min. The transcriptional profiles after and before heat shock were compared.