Project description:We performed ChIP-seq of Hsf1 under non heat shock, 5-minute heat shock and 120 minute heat shock conditions. We used the conditional chemical genetics approach known as “anchor away” (AA) to rapidly inactivate Hsf1. We coupled Hsf1-AA to and nascent RNA seq (NAC)-seq to define the genes whose expression depends on Hsf1 during heat shock.
Project description:Heat shock transcription factors HSF1 and HSF2 both are necessary for proper spermatogenesis, which is disrupted at elevated temperatures. We studied how HSF1 and HSF2 cooperate during the heat shock response in mouse spermatocytes. For this purpose we used ChIP-sequencing. ChIP-Seq analyses revealed that the temperature elevation induces remodeling of HSF1 and HSF2 binding to chromatin. The highest HSF1-chromatin binding was observed at 43°C, when HSF2-chromatin binding was reduced. Many promoters (mainly Hsp genes) were occupied by both heat shock factors at physiological temperature of testes and/or at 38°C. In contrary at 43°C only HSF1 was bound. Obtained results suggest that HSF1 and HSF2 could cooperate in regulation of the transcription of some genes only at physiological temperatures and/or at 38°C. Alteration in HSFs interactions and their binding to chromatin could be one of the reason of increased spermatogenic cell death observed after heat shock.
Project description:Heat shock transcription factors HSF1 and HSF2 both are necessary for proper spermatogenesis, which is disrupted at elevated temperatures. We studied how HSF1 and HSF2 cooperate during the heat shock response in mouse spermatocytes. For this purpose we used ChIP-sequencing. ChIP-Seq analyses revealed that the temperature elevation induces remodeling of HSF1 and HSF2 binding to chromatin. The highest HSF1-chromatin binding was observed at 43M-BM-0C, when HSF2-chromatin binding was reduced. Many promoters (mainly Hsp genes) were occupied by both heat shock factors at physiological temperature of testes and/or at 38M-BM-0C. In contrary at 43M-BM-0C only HSF1 was bound. Obtained results suggest that HSF1 and HSF2 could cooperate in regulation of the transcription of some genes only at physiological temperatures and/or at 38M-BM-0C. Alteration in HSFs interactions and their binding to chromatin could be one of the reason of increased spermatogenic cell death observed after heat shock. On Illumina platform we sequenced DNA immunoprecipitated from isolated spermatocytes using anti-HSF1 antibody or anti-HSF2 antibody. Cells were either untreated (control) or heat shocked for 5-20 minutes. Two PCR-verified ChIP replicates were collected per each sample, and three negative control samples with normal goat serum were included.
Project description:We utilized chromatin immunoprecipitation sequencing (ChIP-seq) to analyze the binding of HSF1 and HSF2 to chromatin under oxidative stress and heat shock. ChIP-seq was performed in mouse embryonic fibroblasts (MEFs) that were exposed to heat shock (HS) or oxidative stress induced by menadione (MD). Antibodies against HSF1 and HSF2 were used for immunoprecipitation.
Project description:Heat shock response (HSR) is critical for survival of organisms undergoing proteotoxic stress. Heat shock factor 1 (HSF1) is widely believed to be the master regulator of this response. Here, we examined the kinetics of the transcriptional response and HSF1 binding changes genome-wide after heat shock (HS) with high sensitivity and high spatial and temporal resolution using PRO-seq and ChIP-seq assays respectively in wild type and in hsf1-deletion mouse embryonic fibroblasts. The transcriptional response is rapid, dynamic, and extensive with activation of several hundred genes and repression of several thousands of genes. Although HSF1 is critically required for classical inducible Heat Shock Protein (HSP) genes, it is not required for the majority of gene activation. HSF1 acts mechanistically to promote RNA polymerase II (Pol II) release from the promoter-proximal pause, while recruitment and initiation of Pol II are predominantly HSF1-independent. Surprisingly, a major class of cytoskeleton genes is immediately (within 2.5 minutes) and transiently activated in an HSF1-independent manner. A second wave of regulation is characterized by robust activation or repression of new sets of genes. The broad repression of thousands of genes, a quarter of which are repressed immediately upon HS and the rest are repressed in the second wave of regulation, is mediated at the level of decreasing Pol II pause release and not at prior steps of Pol II recruitment or initiation. Notably, heat shock does not induce transcription of some previously defined HSP genes, and HSF2 â a homolog of HSF1 â does not compensate for the lack of HSF1. Together, these findings indicate that mammalian cells cope with stress by rapidly inducing pervasive and dramatic changes in transcription that are largely modulated at the step of pause release, and only a fraction of this regulation is HSF1-dependent. Examination of transcriptional regulation before and after heat shock in WT, HSF1-/-, and HSF1&2-/- MEFs
Project description:Heat-Shock Factor 1 (HSF1), master regulator of the heat-shock response, facilitates malignant transformation, cancer cell survival and proliferation in model systems. The common assumption is that these effects are mediated through regulation of heat-shock protein (HSP) expression. However, the transcriptional network that HSF1 coordinates directly in malignancy and its relationship to the heat-shock response have never been defined. By comparing cells with high and low malignant potential alongside their non-transformed counterparts, we identify an HSF1-regulated transcriptional program specific to highly malignant cells and distinct from heat shock. Cancer-specific genes in this program support oncogenic processes: cell-cycle regulation, signaling, metabolism, adhesion and translation. HSP genes are integral to this program, however, even these genes are uniquely regulated in malignancy. This HSF1 cancer program is active in breast, colon and lung tumors isolated directly from human patients and is strongly associated with metastasis and death. Thus, HSF1 rewires the transcriptome in tumorigenesis, with prognostic and therapeutic implications. ChIP-seq was used to characterize HSF1 binding
Project description:FBXW7 modulates stress response by post-translational modification of HSF1 HSF1 orchestrates the heat-shock response upon exposure to heat stress and activates a transcriptional program vital for cancer cells. In this study we assayed for genome-wide localization of HSF1 enrichment in the HCT116 FBXW7 KO colon cells and their wild type counterpart in untreated cells and upon heat shock. These results revealed that accumulation of nuclear HSF1 in FBXW7 KO cells results in rewiring of the HSF1 transcriptional program. Five million cells were used for the ChIP and precipitated using 5 micrograms of antibody (cell signaling, 4356) against human HSF1
Project description:FBXW7 modulates stress response by post-translational modification of HSF1 HSF1 orchestrates the heat-shock response upon exposure to heat stress and activates a transcriptional program vital for cancer cells. In this study we assayed for genome-wide localization of HSF1 enrichment in the HCT116 FBXW7 KO colon cells and their wild type counterpart in untreated cells and upon heat shock. These results revealed that accumulation of nuclear HSF1 in FBXW7 KO cells results in rewiring of the HSF1 transcriptional program.
Project description:We utilized precicion run-on sequencing (PRO-seq) to analyze the roles of HSF1 and HSF2 in the reprogramming of transcription under oxidative stress and heat shock. PRO-seq was performed in wild-type (WT), HSF1 knock-out (HSF1 KO) and HSF2 knock-out (HSF2 KO) mouse embryonic fibroblasts (MEFs) that were treated with heat shock (HS) or oxidative stress induced by menadione (MD).