Gene expression in response to endoplasmic reticulum stress in Arabidopsis thaliana.
Eukaryotic cells respond to the accumulation of unfolded proteins in the endoplasmic reticulum (ER). In this case, so-called unfolded protein response (UPR) genes are induced. We determined the transcriptional expression of Arabidopsis thaliana UPR genes by fluid microarray analysis of tunicamycin-treated plantlets. Two hundred and fifteen up-regulated genes and 17 down-regulated ones were identified. These genes were reanalyzed with functional DNA microarrays, using DNA fragments cloned through fluid microarray analysis. Finally, 36 up-regulated and two down-regulated genes were recognized as UPR genes. Among them, the up-regulation of genes related to protein degradation (HRD1, SEL-1L/HRD3 and DER1), regulation of translation (P58(IPK)), and apoptosis (BAX inhibitor-1) was reconfirmed by real-time reverse transcriptase-PCR. The induction of SEL-1L protein in an Arabidopsis membrane fraction on tunicamycin-treatment was demonstrated. Phosphorylation of initiation factor-2alpha, which was inhibited by P58(IPK), was decreased in tunicamycin-treated plantlets. However, regulatory changes in translation caused by ER stress were not detected in Arabidopsis. Plant cells appeared to have a strategy for overcoming ER stress through enhancement of protein folding activity, degradation of unfolded proteins, and regulation of apoptosis, but not regulation of translation.
Kamauchi
Shinya
S
Graduate School of Agriculture, Kyoto University, Uji, Japan.
Nakatani
Hiromi
H
Nakano
Chiharu
C
Urade
Reiko
R
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D008969:Molecular Sequence Data; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins; D010957:Plasmids; D017510:Protein Folding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014415:Tunicamycin / Q000494:pharmacology; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D029681:Arabidopsis Proteins; D015852:Eukaryotic Initiation Factor-2; C500847:P58IPK protein, plant; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D011994:Recombinant Proteins; D012097:Repressor Proteins; D014415:Tunicamycin; D019892:eIF-2 Kinase