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영어

Various environmental stresses lead to accumulation of unfolded proteins in the endoplasmic reticulum (ER) of plants, resulting in ER stress. In eukaryotic cells, an effective mechanism known as the unfolded protein response (UPR) has evolved to deal with this problem. In plants, UPR facilitates in the folding or degradation of unfolded proteins and regulates the expression of various stress-related genes. Although the stress response induced by phosphorylation of the translation attenuation factor (TAF) is well understood, the mechanism of protein translation regulation is unclear. In this study, to find out the mechanism of protein translation regulation by TAF, the characteristics of stress-related gene expression were analyzed. To analyze the expression of stress-related genes, 5’ UTR of a gene including uORF was fused with green fluorescent protein (GFP), and GFP expression was analyzed under ER stress conditions. As a result of analyzing the protein expression of the gene, it was confirmed that in the case of the gene containing uORF, the protein translation was increased compared to the normal growth condition. However, there was no significant difference at the transcription level. Additional experiments were conducted to confirm whether the regulation of protein translation by uORF is regulated by phosphorylation of TAF. In plants, a mutant of GCN2 (gcn2), known as an TAF kinase, was crossed and the gene expression regulation by TAF was analyzed. As a result, it was confirmed that dephosphorylation of TAF reduced the protein translation of the gene including uORF. However, there was no significant difference at the transcription level. These results showed the consistent results under various stress conditions. Taken together, these results show that plants regulate gene expression at the translation level to adapt to various environmental stresses, suggesting that TAF phosphorylation plays a key role in translation regulation. * Corresponding