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.
Project description:Effect of either FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c - also the effect of FLO11 (MUC1) overexpression in the Σ1278b genetic background The aim of this study was to (1) perform a repeat analysis (to improve statistical analysis of these data sets) similar to data submitted previously (GSE17716) and also (2) study the effect of FLO11 over-expression on the transcriptome. Background: The outer cell wall of the yeast Saccharomyces cerevisiae serves as the interface with the surrounding environment and defines cell-cell and cell-surface interactions. Many of these interactions are facilitated by specific adhesins that belong to the Flo protein family. This family of mannoproteins has been implicated in phenotypes such as flocculation and substrate adhesion as well as pseudohyphal growth. Genetic data strongly suggest that individual Flo proteins are responsible for many specific cellular adhesion phenotypes. However, it remains unclear whether such phenotypes are determined solely by the nature of the expressed FLO genes or rather the result of a combination of FLO gene expression and other cell wall properties and cell wall proteins. Mss11p has been shown to be a central element of FLO1 and FLO11 gene regulation and acts together with the cAMP-PKA-dependent transcription factor Flo8p. We use genome wide transcript analysis to identify genes that are direct ly or indirectly regulated by Mss11p in the genetic backgrounds: Sigma1278b and S288c. Sigma 1278b is the strain historically used for the study of pseudohyphae (FLO11 expression) but we also included S288c as this strain is widely used in the research community and was used to determine the first full genome sequence (Thus correspond with SGD information). We also compare this data with transcriptome data from Sigma 1278b yeast over-expressing FLO8 to compare similarities/differences between these two signalling factors. Finally the effect of FLO11 over-expression in Sigma1278b on global transcription is studied so that we can differentiate between "direct" gene targets of Flo8p or Mss11p, and those regulated as a result by the "indirect" effect caused by modified cell wall Flo11p levels. We used two laboratory yeast strains that behave different with regard to adhesion phenotypes. By comparing yeast deleted in either FLO8 or MSS11 to wild type, or yeast overexpressing these genes, in both genetic backgrounds, we investigate the role of Flo8p and Mss11p on yeast transcription. In addition the effect of the over-expression of the adhesin gene FLO11 was studied in Sigma 1278b. By using similar growth conditions to what we use for adhesion phenotype determination we aim to correlate transcription profile changes to yeast behaviour (phenotypes).
Project description:Effect of either FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c - also the effect of FLO11 (MUC1) overexpression in the Σ1278b genetic background The aim of this study was to (1) perform a repeat analysis (to improve statistical analysis of these data sets) similar to data submitted previously (GSE17716) and also (2) study the effect of FLO11 over-expression on the transcriptome. Background: The outer cell wall of the yeast Saccharomyces cerevisiae serves as the interface with the surrounding environment and defines cell-cell and cell-surface interactions. Many of these interactions are facilitated by specific adhesins that belong to the Flo protein family. This family of mannoproteins has been implicated in phenotypes such as flocculation and substrate adhesion as well as pseudohyphal growth. Genetic data strongly suggest that individual Flo proteins are responsible for many specific cellular adhesion phenotypes. However, it remains unclear whether such phenotypes are determined solely by the nature of the expressed FLO genes or rather the result of a combination of FLO gene expression and other cell wall properties and cell wall proteins. Mss11p has been shown to be a central element of FLO1 and FLO11 gene regulation and acts together with the cAMP-PKA-dependent transcription factor Flo8p. We use genome wide transcript analysis to identify genes that are direct ly or indirectly regulated by Mss11p in the genetic backgrounds: Sigma1278b and S288c. Sigma 1278b is the strain historically used for the study of pseudohyphae (FLO11 expression) but we also included S288c as this strain is widely used in the research community and was used to determine the first full genome sequence (Thus correspond with SGD information). We also compare this data with transcriptome data from Sigma 1278b yeast over-expressing FLO8 to compare similarities/differences between these two signalling factors. Finally the effect of FLO11 over-expression in Sigma1278b on global transcription is studied so that we can differentiate between "direct" gene targets of Flo8p or Mss11p, and those regulated as a result by the "indirect" effect caused by modified cell wall Flo11p levels.
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:In an approach to generate Saccharomyces cerevisiae strains with increased intracellular copper amounts for technical applications we over-expressed the copper transporter CTR1 and a variant of CTR1 with a truncation in the C-terminus after the 300 amino acids (CTR1 delta-300). We determined the copper sensitivity of the generated strains and used inductively coupled plasma spectrometry (ICP-OES and ICP-MS) analysis to investigate the effects of over-expression of both constructs under excess copper on the cellular content of different elements in S. cerevisiae. In addition, we ran DNA microarray analysis to obtain the gene expression profile under the changed element contents. Over-expression of CTR1 increased the copper content in the cells up to 160% and 78 genes were differentially regulated. Over-expression of the truncated CTR1 delta-300 resulted in an increased copper, iron and zinc content of more than 200% and 980 genes showed differential expression. We found that transition metal ion homeostasis was disrupted in CTR1 delta-300 over-expressing strains under excess copper and that this was combined with a transcriptional remodelling of cellular processes Transcription profiling was performed in Saccharomyces cerevisiae BY4741 (referred to as wild type) over-expressing CTR1 and in the ctr1- deletion strain BY4741 delta-ctr1 overexpressing CTR1 delta-300 after 7 hours of culture under excess copper (0.02 mM CuCl2). Control strains contained the corresponding empty vector. Three independent experiments were performed and 12 samples were analyzed.
Project description:In an approach to generate Saccharomyces cerevisiae strains with increased intracellular copper amounts for technical applications we over-expressed the copper transporter CTR1 and a variant of CTR1 with a truncation in the C-terminus after the 300 amino acids (CTR1 delta-300). We determined the copper sensitivity of the generated strains and used inductively coupled plasma spectrometry (ICP-OES and ICP-MS) analysis to investigate the effects of over-expression of both constructs under excess copper on the cellular content of different elements in S. cerevisiae. In addition, we ran DNA microarray analysis to obtain the gene expression profile under the changed element contents. Over-expression of CTR1 increased the copper content in the cells up to 160% and 78 genes were differentially regulated. Over-expression of the truncated CTR1 delta-300 resulted in an increased copper, iron and zinc content of more than 200% and 980 genes showed differential expression. We found that transition metal ion homeostasis was disrupted in CTR1 delta-300 over-expressing strains under excess copper and that this was combined with a transcriptional remodelling of cellular processes
Project description:Effect of FLO8 or MSS11 deletion and -overexpression on yeast transcript profiles compared to wild type in laboratory yeast strains Σ1278b and S288c.