Large organellar changes occur during mild heat shock in yeast.
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ABSTRACT:
SUBMITTER: Keuenhof KS
PROVIDER: S-EPMC8403982 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Yeast prion [PSI(+)] is a self-perpetuating amyloid of the translational termination factor Sup35. Although [PSI(+)] propagation is modulated by heat shock proteins (Hsps), high temperature was previously reported to have little or no effect on [PSI(+)]. Our results show that short-term exposure of exponentially growing yeast culture to mild heat shock, followed by immediate resumption of growth, leads to [PSI(+)] destabilization, sometimes persisting for several cell divisions after heat shock. Prion loss occurring in the first division after heat shock is preferentially detected in a daughter cell, indicating the impairment of prion segregation that results in asymmetric prion distribution between a mother cell and a bud. Longer heat shock or prolonged incubation in the absence of nutrients after heat shock led to [PSI(+)] recovery. Both prion destabilization and recovery during heat shock depend on protein synthesis. Maximal prion destabilization coincides with maximal imbalance between Hsp104 and other Hsps such as Hsp70-Ssa. Deletions of individual SSA genes increase prion destabilization and/or counteract recovery. The dynamics of prion aggregation during destabilization and recovery are consistent with the notion that efficient prion fragmentation and segregation require a proper balance between Hsp104 and other (e.g., Hsp70-Ssa) chaperones. In contrast to heat shock, [PSI(+)] destabilization by osmotic stressors does not always depend on cell proliferation and/or protein synthesis, indicating that different stresses may impact the prion via different mechanisms. Our data demonstrate that heat stress causes asymmetric prion distribution in a cell division and confirm that the effects of Hsps on prions are physiologically relevant.
| S-EPMC3095851 | biostudies-literature
Project description:The Mediator complex is central to transcription by RNA polymerase II (Pol II) in eukaryotes. In budding yeast (Saccharomyces cerevisiae), Mediator is recruited by activators and associates with core promoter regions, where it facilitates preinitiation complex (PIC) assembly, only transiently before Pol II escape. Interruption of the transcription cycle by inactivation or depletion of Kin28 inhibits Pol II escape and stabilizes this association. However, Mediator occupancy and dynamics have not been examined on a genome-wide scale in yeast grown in nonstandard conditions. Here we investigate Mediator occupancy following heat shock or CdCl2 exposure, with and without depletion of Kin28. We find that Pol II occupancy shows similar dependence on Mediator under normal and heat shock conditions. However, although Mediator association increases at many genes upon Kin28 depletion under standard growth conditions, little or no increase is observed at most genes upon heat shock, indicating a more stable association of Mediator after heat shock. Unexpectedly, Mediator remains associated upstream of the core promoter at genes repressed by heat shock or CdCl2 exposure whether or not Kin28 is depleted, suggesting that Mediator is recruited by activators but is unable to engage PIC components at these repressed targets. This persistent association is strongest at promoters that bind the HMGB family member Hmo1, and is reduced but not eliminated in hmo1Δ yeast. Finally, we show a reduced dependence on PIC components for Mediator occupancy at promoters after heat shock, further supporting altered dynamics or stronger engagement with activators under these conditions.
| S-EPMC8744673 | biostudies-literature
Project description:Proximity interactome labelling of Sis1 APEX2 during heat shock revealed its comprehensive interactome.
2023-08-18 | PXD039068 | Pride
Project description:We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25 °C to 37 °C. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of the yeast genes and it is particularly important in shaping the mRNA profile of the genes belonging to the environmental stress response. In most cases, changes in transcription rates and mRNA stabilities are homodirectional for both parameters, although some interesting cases of antagonist behavior are found. The statistical analysis of gene targets and sequence motifs within the clusters of genes with similar behaviors shows that both transcriptional and post-transcriptional regulons apparently contribute to the general heat stress response by means of transcriptional factors and RNA binding proteins.
| S-EPMC3045430 | biostudies-literature
Project description:Mild hypoglycemia is common in clinical practice. Severe hypoglycemia results in heat shock protein and associate co-chaperone changes. Whether mild prolonged hypoglycemia elicits a similar response with inflammatory and oxidative-stress responses compared with a severe hypoglycemic event is unclear; therefore, this pilot exploratory study was undertaken. We performed a case-control induced hypoglycemia clamp study, maintaining blood glucose at 2.8 mmol/L (50 mg/dL) for 1 h in 17 subjects (T2D (n = 10); controls (n = 7)). Blood sampling was performed at baseline, hypoglycemia, and 24 h; slow off-rate modified aptamer (SOMA)-scan plasma protein analysis of HSP-related proteins, inflammatory stress markers, and oxidative stress markers was performed. In total, 16 HSPs were analyzed. At baseline, TLR4:MD-2 complex was elevated (p = 0.01), whilst HSPA8 was lower (p < 0.05) in T2D. At hypoglycemia, UBE2N, STIP1, and UBE2L3 increased (all p < 0.05), whilst TLR4:MD-2 and HSPA8 decreased (p < 0.05) in T2D versus baseline. In follow-up after hypoglycemia, HSPs normalized to baseline by 24 h, except UBE2L3 (p < 0.05), which was decreased in controls versus baseline. Correlation of altered inflammatory markers with HSPs revealed the following: at baseline, TLR4:MD-2 correlated with CXCL10 (p < 0.01) and SIGLEC1 (p < 0.05) in controls; HSPA8 negatively correlated with IL5 (p < 0.05) in T2D. A negative correlation between urinary isoprostane 8-iso PGF2α, a marker of oxidative stress, and HSPA1A was seen at 24 h in T2D only (p < 0.05). In conclusion, the HSP changes seen for mild prolonged hypoglycemia were similar to those previously reported for a severe event. However, mild prolonged hypoglycemia appeared to elicit an increased inflammatory response that was associated with heat shock and related proteins.
| S-EPMC8618421 | biostudies-literature
Project description:These experiments were done to compare the transcriptional response to high temperature of disomic yeast to that of WT yeast.
2012-08-14 | GSE40073 | GEO
Project description:OBJECTIVE:Present study explores the effect of hot summer period on the glycolytic rate of early post-mortem meat quality of Ghungroo and Large White Yorkshire (LWY) pig and comparative adaptability to high temperature between above breeds by shifting the expression of stress related genes like mono-carboxylate transporters (MCTs) and heat shock proteins (HSPs). METHODS:Healthy pigs of two different breeds, viz., LYW and Ghungroo (20 from each) were maintained during hot summer period (May to June) with a mean temperature of about 38°C. The pigs were slaughtered and meat samples from the longissimus dorsi (LD) muscles were analyzed for pH, glycogen and lactate content and mRNA expression. Following 24 h of chilling, LD muscle was also taken from the carcasses to evaluate protein solubility and different meat quality measurements. RESULTS:LWY exhibited significantly (p<0.01) higher plasma cortisol and lactate dehydrogenase concentration than Ghungroo indicating their higher sensitivity to high temperature. LD muscle from LWY pigs revealed lower initial and ultimate pH values and higher drip loss compared to Ghungroo, indicating a faster rate of pH fall. LD muscle of Ghungroo had significantly lower lactate content at 45 min postmortem indicating normal postmortem glycolysis and much slower glycolytic rate at early postmortem. LD muscle of LWY showed rapid postmortem glycolysis, higher drip loss and higher degrees of protein denaturation. Ghungroo exhibited slightly better water holding capacity, lower cooking loss and higher protein solubility. All HSPs (HSP27, HSP70, and HSP90) and MCTs (MCT1, MCT2, and MCT4) in the LD muscle of pigs inclined to increase more in Ghungroo than LWY when exposed to high temperature. CONCLUSION:Effect of high temperature on the variation of HSPs and MCTs may play a crucial role in thermal tolerance and adaptation to different climatic conditions, pH regulation, muscle acidification, drip loss, protein denaturation and also in postmortem meat quality development.
| S-EPMC5205613 | biostudies-literature
Project description:High temperature causes ubiquitous environmental stress to microorganisms, but studies have not fully explained whether and to what extent heat shock would affect genome stability. Hence, this study explored heat-shock-induced genomic alterations in the yeast Saccharomyces cerevisiae. Using genetic screening systems and customized single nucleotide polymorphism (SNP) microarrays, we found that heat shock (52 °C) for several minutes could heighten mitotic recombination by at least one order of magnitude. More than half of heat-shock-induced mitotic recombinations were likely to be initiated by DNA breaks in the S/G2 phase of the cell cycle. Chromosomal aberration, mainly trisomy, was elevated hundreds of times in heat-shock-treated cells than in untreated cells. Distinct chromosomal instability patterns were also observed between heat-treated and carbendazim-treated yeast cells. Finally, we demonstrated that heat shock stimulates fast phenotypic evolutions (such as tolerance to ethanol, vanillin, fluconazole, and tunicamycin) in the yeast population. This study not only provided novel insights into the effect of temperature fluctuations on genomic integrity but also developed a simple protocol to generate an aneuploidy mutant of yeast.
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Project description:A gene regulatory module (GRM) is a set of genes that is regulated by the same set of transcription factors (TFs). By organizing the genome into GRMs, a living cell can coordinate the activities of many genes in response to various internal and external stimuli. Therefore, identifying GRMs is helpful for understanding gene regulation.Integrating transcription factor binding site (TFBS), mutant, ChIP-chip, and heat shock time series gene expression data, we develop a method, called Heat-Inducible Module Identification Algorithm (HIMIA), for reconstructing GRMs of yeast heat shock response. Unlike previous module inference tools which are static statistics-based methods, HIMIA is a dynamic system model-based method that utilizes the dynamic nature of time series gene expression data. HIMIA identifies 29 GRMs, which in total contain 182 heat-inducible genes regulated by 12 heat-responsive TFs. Using various types of published data, we validate the biological relevance of the identified GRMs. Our analysis suggests that different combinations of a fairly small number of heat-responsive TFs regulate a large number of genes involved in heat shock response and that there may exist crosstalk between heat shock response and other cellular processes. Using HIMIA, we identify 68 uncharacterized genes that may be involved in heat shock response and we also identify their plausible heat-responsive regulators. Furthermore, HIMIA is capable of assigning the regulatory roles of the TFs that regulate GRMs and Cst6, Hsf1, Msn2, Msn4, and Yap1 are found to be activators of several GRMs. In addition, HIMIA refines two clusters of genes involved in heat shock response and provides a better understanding of how the complex expression program of heat shock response is regulated. Finally, we show that HIMIA outperforms four current module inference tools (GRAM, MOFA, ReMoDisvovery, and SAMBA), and we conduct two randomization tests to show that the output of HIMIA is statistically meaningful.HIMIA is effective for reconstructing GRMs of yeast heat shock response. Indeed, many of the reconstructed GRMs are in agreement with previous studies. Further, HIMIA predicts several interesting new modules and novel TF combinations. Our study shows that integrating multiple types of data is a powerful approach to studying complex biological systems.
| S-EPMC2575218 | biostudies-literature
Project description:During beer production, yeast generate ethanol that is exported to the extracellular environment where it accumulates. Depending on the initial carbohydrate concentration in the wort, the amount of yeast biomass inoculated, the fermentation temperature, and the yeast attenuation capacity, a high concentration of ethanol can be achieved in beer. The increase in ethanol concentration as a consequence of the fermentation of high gravity (HG) or very high gravity (VHG) worts promotes deleterious pleiotropic effects on the yeast cells. Moderate concentrations of ethanol (5% v/v) change the enzymatic kinetics of proteins and affect biological processes, such as the cell cycle and metabolism, impacting the reuse of yeast for subsequent fermentation. However, high concentrations of ethanol (> 5% v/v) dramatically alter protein structure, leading to unfolded proteins as well as amorphous protein aggregates. It is noteworthy that the effects of elevated ethanol concentrations generated during beer fermentation resemble those of heat shock stress, with similar responses observed in both situations, such as the activation of proteostasis and protein quality control mechanisms in different cell compartments, including endoplasmic reticulum (ER), mitochondria, and cytosol. Despite the extensive published molecular and biochemical data regarding the roles of proteostasis in different organelles of yeast cells, little is known about how this mechanism impacts beer fermentation and how different proteostasis mechanisms found in ER, mitochondria, and cytosol communicate with each other during ethanol/fermentative stress. Supporting this integrative view, transcriptome data analysis was applied using publicly available information for a lager yeast strain grown under beer production conditions. The transcriptome data indicated upregulation of genes that encode chaperones, co-chaperones, unfolded protein response elements in ER and mitochondria, ubiquitin ligases, proteasome components, N-glycosylation quality control pathway proteins, and components of processing bodies (p-bodies) and stress granules (SGs) during lager beer fermentation. Thus, the main purpose of this hypothesis and theory manuscript is to provide a concise picture of how inter-organellar proteostasis mechanisms are connected with one another and with biological processes that may modulate the viability and/or vitality of yeast populations during HG/VHG beer fermentation and serial repitching.
| S-EPMC7006503 | biostudies-literature