Protective roles of methionine-R-sulfoxide reductase against stresses in Schizosaccharomyces pombe.

The Schizosaccharomyces pombe msrB(+) gene encoding methionine-R-sulfoxide reductase (MsrB) was cloned into the shuttle vector pRS316 to generate the recombinant plasmid pFMetSO. The msrB(+) mRNA level was significantly increased in the S. pombe cells harboring pFMetSO, indicating that the cloned msrB(+) gene is functioning. In the presence of 0.1 mM L-methionine-(R,S)-sulfoxide, the S. pombe cells harboring pFMetSO could grow normally but the growth of the vector control cells was almost arrested. The S. pombe cells harboring pFMetSO exhibited the enhanced growth on the minimal medium plates with stress-inducing agents, such as hydrogen peroxide, superoxide radical-generating menadione (MD), nitric oxide (NO)-generating sodium nitroprusside (SNP), and cadmium (Cd), when compared with the vector control cells. They also gave rise to the enhanced growth at the high incubation temperature of 37 °C than the vector control cells. The S. pombe cells harboring pFMetSO contained lower reactive oxygen species (ROS) and higher total glutathione (GSH) levels than the vector control cells. In brief, the S. pombe MsrB plays a protective role against oxidative, nitrosative, and thermal stresses, and is involved in diminishing intracellular ROS level.
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