Project description:A study was carried out to characterise the global transcriptional response of Candida albicans to various environmental stresses, alone and in combinations.
Project description:A study was carried out to characterise the global transcriptional response of Candida albicans to various environmental stresses, alone and in combinations.
Project description:Previous studies on the global transcriptional response of budding yeast, Saccharomyces cerevisiae, to cold shock have revealed that the response can be divided into a set of early response genes (after 15 minutes to 2 hours of cold temperatures) and late response genes (after 12 to 60 hours of cold temperatures). The late response genes include the ESR genes induced by many environmental stresses and are regulated by the Msn2 and Msn4 transcription factors, as they are during other environmental stresses (Kandror et al. 2004 PMID:15053871; Schade et al. 2004 PMID:15483057). However, the transcription factors responsible for the induction of the early response genes, the overall regulatory mechanism governing this early response, and the transcriptional response to recovery after cold shock remain largely unknown. Thus, we measured the early transcriptional response of S. cerevisiae to cold shock and subsequent recovery using DNA microarrays. To determine which transcription factors were responsible for these changes in expression, the same cold shock and recovery microarray experiments were then performed on six strains individually deleted for the transcription factors Cin5, Gln3, Hap4, Hmo1, Swi4, and Zap1.
Project description:Cellular responses to maladaptive environmental changes—stresses—allow for organismal adaptation to diverse and dynamic conditions. Across the tree of life, cells upregulate a highly conserved transcriptional program in response to so-called proteotoxic stresses such as heat shock. Correspondingly, in eukaryotes, these stresses induce the formation of biomolecular condensates, clusters of mRNA and protein which are referred to as stress granules under severe stress. However, major questions remain about this stress-induced response. How conserved is the condensation response relative to the transcriptional response? How does it vary across environmental niches, and to what extent does it correspond with the conserved transcriptional response? To answer these fundamental questions, we studied the growth, transcriptional, and condensation heat-induced stress responses in three fungal species adapted to thrive in different thermal environments: cryophilic S. kudriavzevii, mesophilic S. cerevisiae, and thermotolerant K. marxianus. Here we show that transcriptional heat shock responses track each species’ evolved temperature range of growth. Further, orthologous proteins—including poly(A)-binding protein, Pab1, a core marker of stress granules—form condensates in vivo at temperatures systematically tuned to the temperature at which the organisms activate the transcriptional heat shock response and slow their growth. In vitro, purified Pab1 from each species condenses autonomously at niche-specific temperatures. Homologous mutations in Pab1 cause similar shifts in relative condensation temperature across species, and crucially, mutations which suppress condensation in vitro also reduce fitness during heat stress. Our findings indicate that stress-induced protein condensation is adaptive, conserved, integrated with the growth and transcriptional responses, and tuned to features of the cellular and organismal environment to initiate at niche-specific levels.
Project description:We characterize the genome-wide transcription response of four related yeast species and two strains to equivalent environmental stresses. Keywords: Comparative analysis of gene expression across species.
Project description:We generated a comprehensive RNAseq expression atlas for several stress conditions in order to analyze changes in the gene expression during adaptation to mild stresses. The stresses are divided into two main groups: the “nutrient stresses” and the “environmental stresses”. Nutrient stresses include nutrient depletion (-N, -P, -S, -micronutrients), salt stress (+NaCl), osmotic stress (+mannitol) and control. The environmental stresses consist of high light, prolonged darkness, heat, cold and control.
Project description:Cells must sense and respond to sudden maladaptive environmental changes—stresses—to survive and thrive. Across eukaryotes, stresses such as heat shock trigger conserved responses: growth arrest, a specific transcriptional response, and biomolecular condensation of protein and mRNA into structures known as stress granules under severe stress. The composition, formation mechanism, adaptive significance, and even evolutionary conservation of these condensed structures remain enigmatic. Here we provide an unprecedented view into stress-triggered condensation, its evolutionary conservation and tuning, and its integration into other well-studied aspects of the stress response. Using three morphologically near-identical budding yeast species adapted to different thermal environments and diverged by up to 100 million years, we show that proteome-scale biomolecular condensation is tuned to species-specific thermal niches, closely tracking corresponding growth and transcriptional responses. In each species, poly(A)-binding protein—a core marker of stress granules—condenses in isolation at species-specific temperatures, with conserved molecular features and conformational changes modulating condensation. From the ecological to the molecular scale, our results reveal previously unappreciated levels of evolutionary selection in the eukaryotic stress response, while establishing a rich, tractable system for further inquiry.
Project description:Cells must sense and respond to sudden maladaptive environmental changes—stresses—to survive and thrive. Across eukaryotes, stresses such as heat shock trigger conserved responses: growth arrest, a specific transcriptional response, and biomolecular condensation of protein and mRNA into structures known as stress granules under severe stress. The composition, formation mechanism, adaptive significance, and even evolutionary conservation of these condensed structures remain enigmatic. Here we provide an unprecedented view into stress-triggered condensation, its evolutionary conservation and tuning, and its integration into other well-studied aspects of the stress response. Using three morphologically near-identical budding yeast species adapted to different thermal environments and diverged by up to 100 million years, we show that proteome-scale biomolecular condensation is tuned to species-specific thermal niches, closely tracking corresponding growth and transcriptional responses. In each species, poly(A)-binding protein—a core marker of stress granules—condenses in isolation at species-specific temperatures, with conserved molecular features and conformational changes modulating condensation. From the ecological to the molecular scale, our results reveal previously unappreciated levels of evolutionary selection in the eukaryotic stress response, while establishing a rich, tractable system for further inquiry.
Project description:Aspergillus display an amazing level of diversity in physiologies, and environments that they occupy. Strategies for coping with diverse environmental stresses have evolved in different Aspergillus species. Therefore, Aspergillus are considered to be good models for investigating the adaptation and response to many natural and anthropogenic environmental stressors. Recent genome sequencing projects in several Aspergillus have provided insights into the molecular and genetic mechanisms underlying their responses to some environmental stressors. However, to better clarify the conserved and differentiated features of the adaptive response to specific stresses and to trace the evolutionary process of environmental adaptation and response in Aspergillus, insight from more Aspergillus species with different evolutionary positions, such as A. glaucus, and thus offer a large number of models of adaptation and response to various environmental stresses. Here, we report a high-quality reference genome assembly of A. glaucus CCHA from the surface of wild vegetation around saltern of Jilin, China, based on sequence data from whole-genome shotgun (WGS) sequencing platforms of Illumina solexa technologies. This assembly contains 106 scaffolds ( >1 Kb; N50 = ~0.795 Mb), has a length of ~28.9 Mb and covers ~97% of the predicted genome size (~120 Mb). Together with the data analyses from comprehensive transcriptomic surveys and comparative genomic analyses, we aim to obtain new insights into molecular mechanisms of the adaptation to living at high salt in the saltern