Stress response in yeast mRNA export factor: reversible changes in Rat8p localization are caused by ethanol stress but not heat shock.
Ethanol stress (10% v/v) causes selective mRNA export in Saccharomyces cerevisiae in a similar manner to heat shock (42 degrees C). Bulk poly(A)(+) mRNA accumulates in the nucleus, whereas heat shock protein mRNA is exported under such conditions. Here we investigated the effects of stress on mRNA export factors. In cells treated with ethanol stress, the DEAD box protein Rat8p showed a rapid and reversible change in its localization, accumulating in the nucleus. This change correlated closely with the blocking of bulk poly(A)(+) mRNA export caused by ethanol stress. We also found that the nuclear accumulation of Rat8p is caused by a defect in the Xpo1p/Crm1p exportin. Intriguingly, the localization of Rat8p did not change in heat shocked cells, suggesting that the mechanisms blocking bulk poly(A)(+) mRNA export differ for heat shock and ethanol stress. These results suggest that changes in the localization of Rat8p contribute to the selective export of mRNA in ethanol stressed cells, and also indicate differences in mRNA export between the heat shock response and ethanol stress response.
Laboratory of Molecular Microbiology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
Reiko
R
Takemura
Yoshiharu
Y
Inoue
Shingo
S
Izawa
D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D053487:DEAD-box RNA Helicases; D000431:Ethanol / Q000494:pharmacology*; D018869:Heat-Shock Response / Q000502:physiology*; D028884:Karyopherins / Q000378:metabolism; D029543:Nucleocytoplasmic Transport Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D020365:RNA Helicases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012331:RNA, Fungal / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D000097606:Exportin 1 Protein
D053487:DEAD-box RNA Helicases; D000431:Ethanol; D028884:Karyopherins; D029543:Nucleocytoplasmic Transport Proteins; D020365:RNA Helicases; D012331:RNA, Fungal; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; D000097606:Exportin 1 Protein; C492382:DBP5 protein, S cerevisiae