Involvement of the Saccharomyces cerevisiae UTH1 gene in the oxidative-stress response.

The UTH1 gene was identified by screening a Saccharomyces cerevisiae promoter-probe gene bank for oxidative stress-responsive genes. Transcription of UTH1 was decreased by the superoxide anion and increased by hydrogen peroxide. Deletion of UTH1 did not affect the growth of grande cells, however in a rho0 background it caused retarded growth.

Hydrogen peroxide causes RAD9-dependent cell cycle arrest in G2 in Saccharomyces cerevisiae whereas menadione causes G1 arrest independent of RAD9 function.

This study shows differences at the level of cell cycle arrest between the response of yeast cells to hydrogen peroxide and superoxide stress. These include both cell cycle phases at which arrest occurs and the involvement of the RAD9 checkpoint gene. Wild-type and rad9 cells were treated with hydrogen peroxide or the superoxide-generating agent menadione.

Stationary-phase regulation of the Saccharomyces cerevisiae SOD2 gene is dependent on additive effects of HAP2/3/4/5- and STRE-binding elements.

SOD2, encoding manganese superoxide dismutase (MnSOD), is essential for stationary-phase survival of yeast cells. In addition, stationary-phase cells are more resistant to oxidative stress than exponential-phase cells. The use of a SOD2::lacZ fusion construct in this study shows that transcription of SOD2 increases 6.

Saccharomyces cerevisiae has an inducible response to menadione which differs from that to hydrogen peroxide.

Exponential phase cells of Saccharomyces cerevisiae treated with the superoxide free-radical generating agent menadione (MD; 0.2 mM) for 60 min adapted to become resistant to the lethal effects of a higher concentration of MD (4 mM). Inhibition of protein synthesis by treatment with cycloheximide totally prevented the adaptation to MD, indicating that this is an inducible response completely dependent on protein synthesis; this differs from the situation with peroxide in which only some of the adaptive response is cycloheximide-sensitive.