Nucleolus as an oxidative stress sensor in the yeast Saccharomyces cerevisiae.
In mammals, the nucleolus is thought to be a stress sensor; upon cellular stress conditions, a release of nucleolar proteins and down-regulation of rDNA transcription occurs. Since yeast Rrn3p is a homolog of the mammalian RNA polymerase I (Pol I)-specific transcription factor TIF-IA, we decided to investigate the role of Rrn3p in oxidant-induced nucleolar stress in yeast. We show that, after oxidant treatment, the level of Rrn3p is unaffected but Rrn3p is translocated from the nucleolus into the cytoplasm and a point mutation in the RRN3 gene leads to hypersensitivity of the yeast to oxidants. This hypersensitivity can be abolished by re-introduction of the active RRN3 gene, antioxidant supplementation and anoxic atmosphere. Additionally, we employed the PRINS technique to monitor oxidant-mediated changes in the nucleolar structure. Taken together, our results suggest the role of the yeast nucleolus in the response to oxidative stress signals.
Lewinska
Anna
A
Department of Biochemistry and Cell Biology, University of Rzeszow, Pigonia 6, PL35-959 Rzeszow, Poland. alewinska@o2.pl
Wnuk
Maciej
M
Grzelak
Agnieszka
A
Bartosz
Grzegorz
G
D000975:Antioxidants / Q000378:metabolism; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D018384:Oxidative Stress / Q000235:genetics / Q000502:physiology*; D035463:Pol1 Transcription Initiation Complex Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
D000975:Antioxidants; D035463:Pol1 Transcription Initiation Complex Proteins; C101161:RRN3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins