title: Yeast unfolded protein response pathway regulates expression of genes for anti-oxidative stress and for cell surface proteins.
abstract: The unfolded protein response (UPR) is a cellular protective event against endoplasmic reticulum (ER) stress. In the yeast UPR signaling pathway, the ER-located transmembrane protein Ire1 promotes splicing of the HAC1 premRNA (HAC1(u)) to produce the translatable transcription factor mRNA (HAC1i). We generated a HAC1i gene-bearing strain, in which the UPR pathway was constitutively activated, and compared its gene expression profile with that of a Deltaire1 HAC1u strain using cDNA microarray technology. Comparison of the gene expression profile was also performed between non-stressed wild-type cells and those exposed to ER stress. Genes for which the expression level was significantly changed in both of these experiments were categorized as targets of the Ire1-HAC1 signaling pathway. This analysis revealed that in addition to the previously known UPR targets, some anti-oxidative stress genes were up-regulated by the Ire1-HAC1 pathway, possibly in order to reduce reactive oxygen species produced during the cellular response to ER stress. Moreover, we categorized 15 genes as those down-regulated by the UPR, most of which seem to encode cell surface or extracellular proteins. This UPR-mediated gene repression may alleviate the load of client proteins targeted to the ER.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan. kimata@zero.ad.jp
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kimata
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ishiwata-Kimata
authors.forename: Seiko
authors.initials: S
authors.lastname: Yamada
authors.forename: Kenji
authors.initials: K
authors.lastname: Kohno
mesh_terms: D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D004721:Endoplasmic Reticulum / Q000378:metabolism; D020869:Gene Expression Profiling; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress; D010544:Peroxidases / Q000378:metabolism; D017510:Protein Folding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; C091341:HAC1 protein, S cerevisiae; D008565:Membrane Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; D010544:Peroxidases; C496253:Tsa1 protein, S cerevisiae