Menin links the stress response to genome stability in Drosophila melanogaster
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ABSTRACT: Mutants of the Mnn1 gene are hyper-sensitive to several stresses and display increased genome instability when subjected to conditions, such as heat shock, generally regarded as non-genotoxic. We describe a role for Menin as a global regulator of heat shock gene expression and critical factor in the maintenance of genome integrity 2-colour microarray design using 36 microarrays testing shock vs non shock in Drosophila melanogaster. Using a test of loss-of-heterozygosity, we show that Drosophila strains lacking a functional Mnn1 gene or expressing a Mnn1 dsRNAi are characterized by increased genome instability in response to short, repeated but non-lethal heat shock or hypoxia treatments. The same was true for strains lacking all Hsp70 genes.
Project description:ESTs in which transcription levels in oyster gill differed among sampling times after heat shock and between families with high or low survival of heat shock were identified through expression profiling of 1,675 spot pairs Keywords: comparison of families characterized by low or high survival after heat shock Oyster families were characterized by survival after heat shock, exposed to a sub-lethal heat shock, and gill was collected before and at 1, 3, 6, and 24 h afterwards. Differences among sampling times and between family types were assessed using a 2-way analysis of variance. In total, 1,675 ESTs were included in the analysis.
Project description:The initially homogeneous epithelium of the early Drosophila embryo differentiates into regional subpopulations with different behaviours and physical properties that are needed for morphogenesis. The factors at top of the genetic hierarchy that control these behaviours are known, but many of their targets are not. To understand how proteins work together to mediate differential cellular activities, we studied in an unbiased manner the proteomes and phosphoproteomes of the three main cell populations along the dorso-ventral axis during gastrulation using mutant embryos that represent the different populations. We detected 6111 protein groups and 6259 phosphosites of which 3399 and 3433 respectively, were differentially regulated. The changes in phosphosite abundance did not correlate with changes in host protein abundance, showing phosphorylation to be a regulatory step during gastrulation. Hierarchical clustering of protein groups and phosphosites identified clusters that contain known fate determinants such as Doc1, Sog, Snail and Twist. The recovery of the appropriate known marker proteins in each of the different mutants we used validated the approach, but also revealed that two mutations that both interfere with the dorsal fate pathway, Toll10B and serpin27aex do this in very different manners. Diffused network analyses within each cluster point to microtubule components as one of the main groups of regulated proteins. Functional studies on the role of microtubules provide the proof of principle that microtubules have different functions in different domains along the DV axis of the embryo. This repository is related to PXD046050 which represents the label-free proteome.
Project description:In Drosophila larvae, acquired synaptic thermotolerance following heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (hsf4) which has been reported not to be able to produce inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses following heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1(hsp40) and gstE1 genes were significantly up-regulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blotting. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory up-regulation of constitutively expressed Hsps, in the absence of the synthesis of inducible Hsps including HSP70, could still provide substantial thermoprotection to both synapses and the whole organism. Two strains were used in this study; the mutant cn bw hsf4 strain, and the dp cn bw cl control strain from which the mutant was derived. For each strain, co-reared larvae were separated into a control group and a treatment group at random. RNA from the heat-shocked larvae and from the respective controls were directly compared on cDNA microarrays (GPL311). Two independent biological samples from each genotype were collected. In addition, an inter-strain comparison was made using the RNA from the untreated controls from each genotype. This was also performed in duplicate.
Project description:The initially homogeneous epithelium of the early Drosophila embryo differentiates into regional subpopulations with different behaviours and physical properties that are needed for morphogenesis. The factors at top of the genetic hierarchy that control these behaviours are known, but many of their targets are not. To understand how proteins work together to mediate differential cellular activities, we studied in an unbiased manner the proteomes and phosphoproteomes of the three main cell populations along the dorso-ventral axis during gastrulation using mutant embryos that represent the different populations. We detected 6111 protein groups and 6259 phosphosites of which 3399 and 3433 respectively, were differentially regulated. The changes in phosphosite abundance did not correlate with changes in host protein abundance, showing phosphorylation to be a regulatory step during gastrulation. Hierarchical clustering of protein groups and phosphosites identified clusters that contain known fate determinants such as Doc1, Sog, Snail and Twist. The recovery of the appropriate known marker proteins in each of the different mutants we used validated the approach, but also revealed that two mutations that both interfere with the dorsal fate pathway, Toll10B and serpin27aex do this in very different manners. Diffused network analyses within each cluster point to microtubule components as one of the main groups of regulated proteins. Functional studies on the role of microtubules provide the proof of principle that microtubules have different functions in different domains along the DV axis of the embryo.
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. Genes positively regulated by HSF1 show increeased expression during heat shock while their expression is reduced during recovery. Genes negatively regulated by HSF1 show the opposite pattern. In this study we utilized the HCT116 FBXW7 KO colon cell line and its wild type counterpart to monitor gene expression changes during heat shock (42oC, 1 hour) and recovery (37oC for 2 hours post heat shock) using RNA sequencing. These results revealed that the heat-shock response pathway is prolonged in cells deficient for FBXW7. Whole RNA was extracted from 1 million HCT116 WT or FBXW7KO cells using the RNAeasy kit (Qiagen) according to the manufacturer’s protocol. Poly-A+ (magnetic oligodT-containing beads (Invitrogen)) or Ribominus RNA was used for library preparation. cDNA preparation and strand-specific library construction was performed using the dUTP method. Libraries were sequenced on the Illumina HiSeq 2000 using 50bp single-read method. Differential gene expression analysis was performed for each matched recovery versus heat-shock pairs, separately in each biological replicate and cell line (WT or KO). Two types of comparisons were tested: (a) WT recovery vs WT heat shock, (b) FBXW7 KO recovery vs heat shock.
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:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genomic instability. In this study, heat-shock-induced genomic alterations were explored in the heterozygous diploid yeast strain JSC25-1. In combination of the whole-genome microarray, the patterns of chromosomal instability induced by heat shock could also be explored at a whole genome level. Using this system, we found heat-shock treatment resulted in hundreds-fold higher rate of genomic alterations, including aneuploidy and loss of heterozygosity (LOH).
Project description:A phosphoproteomic analysis of heat shock response in the mammalian infective bloodstream form Trypanosoma brucei was conducted using SILAC-based quantitation. Treatment at 41 0C for 1h produced significantly altered phosphorylation at 193 sites and significantly altered the abundance of 20 proteins.
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:In Huntington's disease (HD), polyglutamine expansions in the huntingtin (Htt) protein cause subtle changes in cellular functions that, over-time, lead to neurodegeneration and death. Studies have indicated that activation of the heat shock response can reduce many of the effects of mutant Htt in disease models, suggesting that the heat shock response is impaired in the disease. To understand the basis for this impairment, we have used genome-wide chromatin immunoprecipitation followed by massively parallel sequencing (ChIP-Seq) to examine the effects of mutant Htt on the master regulator of the heat shock response, HSF1. We find that, under normal conditions, HSF1 function is highly similar in cells carrying either wild-type or mutant Htt. However, polyQ-expanded Htt severely blunts the HSF1-mediated stress response. Surprisingly, we find that the HSF1 targets most affected upon stress are not directly associated with proteostasis, but with cytoskeletal binding, focal adhesion and GTPase activity. Our data raise the intriguing hypothesis that the accumulated damage from life-long impairment in these stress responses may contribute significantly to the etiology of Huntington's disease. Affymetrix MG430 2.0 expression levels of wild-type (STHdhQ7/Q7) and mutant (STHdhQ111/Q111) striatal cells under growth condition (33 C) and upon heat shock (42 C for six hours)