Project description:In somatic cells elevated temperature induces activation of the heat shock transcription factor 1 (HSF1) what leads to heat shock proteins synthesis and cytoprotection. However, in the male germ cells (spermatocytes) upon HSF1 activation, caspase-3 dependent apoptosis is induced and spermatogenic cells are actively eliminated. To find out molecular targets of HSF1 in all promoter regions, and to elucidate a mechanism of such diverse HSF1 activity we carried out genome-wide HSF1 binding analysis in control and heat-shocked cells, either spermatogenic or somatic. As model somatic cells we used hepatocytes that respond to hyperthermia in a classical way by induction of heat shock genes transcription. As spermatogenic cells we used a fraction of cells enriched with spermatocytes, which are the most sensitive to damage in elevated temperatures. Using isolated spermatocytes we avoided the influence of the somatic testicular component on the our final results. On Affymetrix GeneChipM-BM-. Mouse Promoter 1.0R Arrays we analyzed DNA immunoprecipitated (using anty-HSF1 antibody) from spermatocytes or hepatocytes, either untreated (control) or immediately after heat shock performed in vitro for 5-20 minutes. ChIP on chip analyses were done in triplicate.
Project description:In somatic cells elevated temperature induces activation of the heat shock transcription factor 1 (HSF1) what leads to heat shock proteins synthesis and cytoprotection. However, in the male germ cells (spermatocytes) upon HSF1 activation, caspase-3 dependent apoptosis is induced and spermatogenic cells are actively eliminated. To find out molecular targets of HSF1 in all promoter regions, and to elucidate a mechanism of such diverse HSF1 activity we carried out genome-wide HSF1 binding analysis in control and heat-shocked cells, either spermatogenic or somatic. As model somatic cells we used hepatocytes that respond to hyperthermia in a classical way by induction of heat shock genes transcription. As spermatogenic cells we used a fraction of cells enriched with spermatocytes, which are the most sensitive to damage in elevated temperatures. Using isolated spermatocytes we avoided the influence of the somatic testicular component on the our final results.
Project description:In somatic cells elevated temperature induces activation of the heat shock transcription factor 1 (HSF1) what leads to heat shock proteins synthesis and cytoprotection. However, in the male germ cells (spermatocytes) upon HSF1 activation, caspase-3 dependent apoptosis is induced and spermatogenic cells are actively eliminated. To elucidate a mechanism of such diverse HSF1 activity we carried out genome-wide transcriptional analysis in control and heat-shocked cells, either spermatogenic or somatic. As model somatic cells we used hepatocytes that respond to hyperthermia in a classical way by induction of heat shock genes transcription. As spermatogenic cells we used a fraction of cells enriched with spermatocytes, which are the most sensitive to damage in elevated temperatures. Using isolated spermatocytes we avoided the influence of the somatic testicular component on the our final results. Genes that are differently regulated during hyperthermia in both types of cells have been identified. On Affymetrix gene chip arrays we analyzed RNA isolated from spermatocytes or hepatocytes, either untreated (control) or after heat shock and 2h of recovery at physiological temperature. Analyses were done in triplicate.
Project description:In somatic cells elevated temperature induces activation of the heat shock transcription factor 1 (HSF1) what leads to heat shock proteins synthesis and cytoprotection. However, in the male germ cells (spermatocytes) upon HSF1 activation, caspase-3 dependent apoptosis is induced and spermatogenic cells are actively eliminated. To elucidate a mechanism of such diverse HSF1 activity we carried out genome-wide transcriptional analysis in control and heat-shocked cells, either spermatogenic or somatic. As model somatic cells we used hepatocytes that respond to hyperthermia in a classical way by induction of heat shock genes transcription. As spermatogenic cells we used a fraction of cells enriched with spermatocytes, which are the most sensitive to damage in elevated temperatures. Using isolated spermatocytes we avoided the influence of the somatic testicular component on the our final results. Genes that are differently regulated during hyperthermia in both types of cells have been identified.
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:Heat shock induces rapid modification of proteins with SUMO2/3. This study concentrated in charaterizing how these changes are reflected on SUMOylation of chromatin bound proteins, trancsription, and chromatin binding of SUMO ligase PIAS1. Comparison of chromatin SUMO2/3 modification pattern in non-stressed and heat shocked K562 and VCaP cells. All samples were done as biological replicates. In K562 cells, SUMO2/3 ChIP-seq was done in non-stressed (37C) and heat shocked (30min at 43C) cells. The effect of heat shock factor 1 (HSF1) to chromatin SUMOylation in HS was studied in HSF1 silenced (shHSF1) K562 cells (non-stressed vs. heat shocked) using scramble shRNA transfected cells as control (shSCR). SUMO2/3, SUMO ligase PIAS1,and RNA polymerase II binding in HS (30 min at 43C) and recovery from HS (1h at 37C after HS) was studied using ChIP-seq. Effect of PIAS1 for chromatin SUMOylation was studied in PIAS1 silenced (siRNA for PIAS1, siPIAS1) cells (non-stressed or heat shocked) using non-targeting siRNA transfected cells as a control (siNON). Effect of SUMOylation to chromatin binding of RNA polymerase II was studied in UBE2I silenced (siRNA for UBE2I) and control (non-targeting siRNA transfected, siNON) VCaP cells (non-stressed or heat shocked). Effect of transtription inhibition for chromatin SUMOylation was studied in TRP (triptolide; 1 micromolar, 3h) and DRB (5,6-Dichlorobenzimidazole 1-beta-D-ribofuranosidase; 100 micromolar, 3h) treated VCaP cells. GRO-seq was used to determine HS-induced changes in nascent transcription in K562 cells.
Project description:Heat shock transcription factor 1 (HSF1) is responsible for triggering stress-induced activation of the HSP genes. HSF1 is also involved in the regulation of many other genes associated with multiple cellular processes including cell signaling, development, fertility, cell death and metabolism, e.g. NFkappaB transcription factor. Here we aimed to establish a global picture for the association between hyperthermia-modulated expression of NFkappaB-dependent genes and HSF1 binding in regulatory regions of target genes. The global pattern of HSF1 binding was analyzed after 10 and 20 minutes of hyperthermia using the ChIP-Seq approach. The analysis revealed about 25,000 HSF1 binding sites in chromatin of control untreated U-2 OS cells, which nearly doubled in cells subjected to hyperthermia. The presence of hyperthermia-induced HSF1 binding was established in regulatory regions of hyperthermia-affected genes and in TNF-affected genes. In most cases hyperthermia pre-conditioning inhibited cytokine-mediated activation of NF-?B-dependent genes. However, our results also revealed novel gene subsets that included TNFalpha-regulated and hyperthermia-unaffected genes, as well as genes (co)repressed, (co)stimulated, or antagonized by both types of stimuli. On Illumina platform we sequenced DNA immunoprecipitated from U-2 OS cells using anti-HSF1 antibody. Cells were either untreated (control) or heat shocked for 10 and 20 minutes. Two PCR-verified ChIP replicates were collected per each sample.
Project description:Activation of the Heat Shock Factor 1 (HSF1) in spermatogenic cells leads to apoptosis and infertility of males. To elucidate a mechanisms of apoptosis induced by HSF1 we generated transgenic mice expressing mutated, constitutively active human HSF1 (with a deletion of amino acids 221–315) specifically in spermatocytes (under control of the rat Hspa2 promoter). We carried out genome-wide transcriptional analyses in testes of control, wild-type, and transgenic males. Genes that changed the expression due to activation of HSF1 have been identified.