Rsp5 is required for the nuclear export of mRNA of HSF1 and MSN2/4 under stress conditions in Saccharomyces cerevisiae.
Rsp5 is an essential and multi-functional E3 ubiquitin ligase in Saccharomyces cerevisiae. We previously isolated the Ala401Glu rsp5 mutant that is hypersensitive to various stresses. In rsp5(A401E) cells, the transcription of the stress protein genes was defective. To understand the mechanism by which Rsp5 regulates the expression of stress proteins, we analyzed the expression and localization of two major transcription factors, Hsf1 and Msn2/4, required for stress protein gene expression in S. cerevisiae. The mRNA levels of HSF1 and MSN2/4 in rsp5(A401E) cells were slightly lower than those of wild-type cells. An interesting finding is that the protein levels of HSF1 and Msn2/4 were remarkably defective in rsp5(A401E) cells after exposure to temperature up-shift and ethanol, although these proteins are mainly localized in the nucleus under these stress conditions. We also showed that the mRNAs of HSF1 and MSN2/4 were accumulated in the nucleus of rsp5(A401E) cells after exposure to temperature up-shift and ethanol, and even under non-stress conditions, suggesting that Rsp5 is required for the nuclear export of these mRNAs. These results indicate that, in response to environmental stresses, Rsp5 primarily regulates the expression of Hsf1 and Msn2/4 at the post-transcriptional level and is involved in the repair system of stress-induced abnormal proteins.
Haitani
Yutaka
Y
Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
Takagi
Hiroshi
H
D021581:Active Transport, Cell Nucleus; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport; D015870:Gene Expression; D005800:Genes, Fungal; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics* / Q000378:metabolism*
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; C067168:HSF1 protein, S cerevisiae; D006360:Heat-Shock Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D012331:RNA, Fungal; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D043743:Ubiquitin-Protein Ligase Complexes; C469287:RSP5 protein, S cerevisiae