Project description:Telomere chromatin structure is pivotal for maintaining genome stability by regulating the binding of telomere-associated proteins and inhibition of a DNA damage response. In yeast, the silent information regulator (Sir) proteins bind to terminal telomeric repeats and to subtelomeric X-elements resulting in histone deacetylation and transcriptional silencing. Herein, we show that sir2 mutant strains display a very specific loss of a nucleosome residing in the X-element. Most yeast telomeres contain an X-element and the nucleosome occupancy defect in sir2 mutants is remarkably consistent between different telomeres.
Project description:We performed massive screening of the genes in yeast that were involved in the tolerance to isopropanol using the non-essential genes deleted yeast collection, and identified sixty-five disruptants that grew slower than the wild type strain in the presence of isopropanol. The isopropanol sensitive mutants were tested to know their behaviour under other alcohol stresses. Besides, we conducted microarray analysis to reveal the transcriptional response to isopropanol stress in yeast. Our results certainly provide new insights into yeast response to C3 alcohol isopropanol.
Project description:Samples GSM206658-GSM206693: Acquired Stress resistance in S. cerevisiae: NaCl primary and H2O2 secondary Transcriptional timecourses of yeast cells exposed to 0.7M NaCl alone, 0.5mM H2O2 alone, or 0.5mM H2O2 following 0.7M NaCl, all compared to an unstressed sample. Repeated using msn2∆ strain. Samples GSM291156-GSM291196: Transcriptional response to stress in strains lacking MSN2 and/or MSN4 Transcriptional timecourses of yeast cells (WT, msn2∆, msn4∆, or msn2∆msn4∆) exposed to 0.7M NaCl for 45 minutes or 30-37˚C Heat Shift for 15 min compared to an unstressed sample of the same strain. Keywords: Stress Response
Project description:Saccharomyces cerevisiae has been used as a secretion host for production of various products, including pharmaceuticals. However, few antibody molecules have been functionally expressed in S. cerevisiae due to the incompatible surface glycosylation. Our laboratory previously isolated a group of yeast mutant strains with different α-amylase secretory capacities, and these evolved strains have showed advantages for production of some heterologous proteins. However, it is not known whether these secretory strains are generally suitable for pharmaceutical protein production. Here, three non-glycosylated antibody fragments with different configurations (Ran-Fab fragment Ranibizumab, Pex-the scFv peptide Pexelizumab, and Nan-a single V-type domain) were successfully expressed and secreted in three background strains with different secretory capacities, including HA (wild type), MA (evolved strain), and LA (evolved strain). However, the secretion of Ran and Nan were positively correlated with the strains’ secretory capacity, while Pex was most efficiently secreted in the parental strain. Therefore, transcriptional analysis was performed to explore the fundamental changes triggered by the expression of the different pharmaceutical proteins in these selected yeast strains.
Project description:During fermentation Saccharomyces yeast produces various aroma-active metabolites determining the different characteristics of aroma and taste in fermented beverages. Amino acid utilization by yeast during brewer´s wort fermentation is seen as linked to flavour profile. To better understand the relationship between the biosynthesis of aroma relevant metabolites and the importance of amino acids, DNA microarrays were performed for Saccharomyces cerevisiae strain S81 and Saccharomyces pastorianus var. carlsbergensis strain S23, respectively. Thereby, changes in transcription of genes were measured, which are associated with amino acid assimilation and its derived aroma-active compounds during fermentation.
Project description:Genetic and environmental stresses are known factors that influence an organisms phenotype. Time is rarely taken into consideration when studying phenotypic changes in cells. Time-resolved microarray data revealed genome-wide transcriptional changes in yeast strain CEN.PK122 oscillating with~2 periods. We mapped the global patterns of transcriptional oscillationsinto a 3-dimensional map to represent different cellular phenotypes ofoscillation period. This map shows the dynamic nature of transcripts through time and concentration space, and that they are ordered and coupled to each other.
Project description:We analyzed genome-wide transcriptional profiles of Saccharomyces cerevisiae BY4742 strain in response to BPA, focusing on two exposure scenarios: (i) low-observed-effect concentration (<10% inhibition) to examine chronic effect of BPA on yeast population, and (ii) high-inhibitory concentration (>70% inhibition) to study acute effect. Initially, yeast cells were exposed to various concentrations of BPA. 50 mg/L and 300 mg/L BPA were determined as low-observed-effect concentration and the high-inhibitory concentration, respectively. Transcriptional profiles indicated that 81 genes were repressed and 104 genes were induced in response to 50 mg/L BPA. On the other hand, in 300 mg/L BPA exposure, 378 genes were down-regulated, while 606 genes were significantly up-regulated. Our data showed that there were similar processes affected by both concentrations such as mitochondria, nucleobase-containing small molecule metabolic process, transcription from RNA polymerase II promoter, and mitotic cell cycle and associated processes. However, different modes of actions of the BPA were found between two concentrations. 300 mg/L BPA exposure showed severe effects on the processes by repressing or inducing several genes or total mechanisms with high level of expression changes, while 50 mg/L BPA exposure changed the expression of some important genes with low level of expression changes in the processes. These results suggest that yeast cells respond via different ways to the different concentrations of BPA at transcriptomic level.