Project description:Cbf1 is a basic helix-loop-helix transcription factor which regulates the expression of many genes of the sulphur assimilation pathway in yeast. Gamma-glutamylcysteine synthetase (GSH1), encoding the rate-limiting enzyme in glutathione biosynthesis, is constitutively elevated in cbf1 mutants indicating that Cbf1 normally represses GSH1 expression. We used transcriptional profiling to show that a number of antioxidant and stress genes are similarly repressed by Cbf1, consistent with the high oxidant tolerance of cbf1 mutants. Our data indicate that Cbf1 plays a key role in the regulation of gene expression during oxidative stress conditions induced by exposure to hydrogen peroxide. The Yap1 transcription factor induces GSH1 expression in response to hydrogen peroxide in a mechanism that does not require the Met4 transcription factor to overcome the inhibitory action of Cbf1. We show that hydrogen peroxide does not affect Cbf1 occupancy on the GSH1 promoter, but results in specific modification of Cbf1 by phosphorylation. Our data indicate that casein kinase (CK2) can directly phosphorylate Cbf1 in vitro. Furthermore, CK2 activity is required to phosphorylate Cbf1 and induce GSH1 expression in yeast cells in response to hydrogen peroxide. CK2 mutants are sensitive to hydrogen peroxide consistent with a role for CK2 in regulating the cellular response to oxidative stress. CK2 is a ubiquitous serine/threonine protein kinase and the finding that it is regulated by oxidative stress is particularly interesting, since there is increasing evidence that it is involved in a number of pathological conditions including cancer, neurodegenerative and cardiovascular diseases.
Project description:Oxidative stress caused by Menadione or Hydrogen peroxide in synchronized Saccharomyces cerevisiae cultures. Alpha factor synchronized cultures (0.2-0.4 OD), treated at the beginning of S phase (25 min after release from G1 arrest) with either 2 mM Menadione (MD) or 0.24 mM Hydrogen peroxide (HP), show cell cycle effects. Cells treated with MD arrested at G1. Cells treated with HP delayed at S and then, after removal of HP at 135 minutes , continued the cell cycle, only to arrest at G2/M. Growth was carried out in 30C with shaking (295 rpm). Two time course experiments were performed with each oxidative stress agent, designated as H2O2 and H2O2_II, MD and MD_II. Keywords = oxidative stress Keywords = menadione Keywords = hydrogen peroxide Keywords = time course Keywords = cell cycle Keywords = yeast Keywords: other
Project description:Oxidative stress caused by Menadione or Hydrogen peroxide in synchronized Saccharomyces cerevisiae cultures. Alpha factor synchronized cultures (0.2-0.4 OD), treated at the beginning of S phase (25 min after release from G1 arrest) with either 2 mM Menadione (MD) or 0.24 mM Hydrogen peroxide (HP), show cell cycle effects. Cells treated with MD arrested at G1. Cells treated with HP delayed at S and then, after removal of HP at 135 minutes , continued the cell cycle, only to arrest at G2/M. Growth was carried out in 30C with shaking (295 rpm). Two time course experiments were performed with each oxidative stress agent, designated as H2O2 and H2O2_II, MD and MD_II. Keywords = oxidative stress Keywords = menadione Keywords = hydrogen peroxide Keywords = time course Keywords = cell cycle Keywords = yeast
Project description:To gain insight into the basic mechanism of Hydrogen peroxide detoxification in the methylotrophic yeast, H. polymorpha, we analyzed changes in transcriptional profiles in response to hydrogen peroxide exposure.
Project description:Reactive oxygen species such as hydrogen peroxide occur in all aerobically living organisms. Oxidative stress during fermentation can impair the fitness of the production host and the quality of the product. B. pumilus has been described as highly resistant to hydrogen peroxide. The response of exponentially growing B. pumilus cells to hydrogen peroxide was studied.
Project description:Yeast cells response during recovery after hydrogen peroxide stress. Comparison of yeast cells treated with 1.5mM hydrogen peroxide for 30 min with cells allowed to recover for 60 min
Project description:Reactive oxygen species such as hydrogen peroxide occur in all aerobically living organisms. Oxidative stress during fermentation can impair the fitness of the production host and the quality of the product. B. pumilus has been described as highly resistant to hydrogen peroxide. The response of exponentially growing B. pumilus cells to hydrogen peroxide was studied. Two-condition experiment, unstressed versus hydrogen peroxide stressed cells, 3 biological replicates