Gómez-Pastor Rocío, Garre Elena, Pérez-Torrado Roberto, Matallana Emilia
Departament de Bioquímica i Biologia Molecular, Universitat de València, Valencia, Spain.
Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, CSIC, 7 Paterna, Valencia, Spain.
PLoS One. 2013 Dec 23;8(12):e85404. doi: 10.1371/journal.pone.0085404. eCollection 2013.
The whole genome analysis has demonstrated that wine yeasts undergo changes in promoter regions and variations in gene copy number, which make them different to lab strains and help them better adapt to stressful conditions during winemaking, where oxidative stress plays a critical role. Since cytoplasmic thioredoxin II, a small protein with thiol-disulphide oxidoreductase activity, has been seen to perform important functions under biomass propagation conditions of wine yeasts, we studied the involvement of Trx2p in the molecular regulation of the oxidative stress transcriptional response on these strains. In this study, we analyzed the expression levels of several oxidative stress-related genes regulated by either Yap1p or the co-operation between Yap1p and Skn7p. The results revealed a lowered expression for all the tested Skn7p dependent genes in a Trx2p-deficient strain and that Trx2p is essential for the oxidative stress response during respiratory metabolism in wine yeast. Additionally, activity of Yap1p and Skn7p dependent promoters by β-galactosidase assays clearly demonstrated that Skn7p-dependent promoter activation is affected by TRX2 gene deficiency. Finally we showed that deleting the TRX2 gene causes Skn7p hyperphosphorylation under oxidative stress conditions. We propose Trx2p to be a new positive efector in the regulation of the Skn7p transcription factor that controls phosphorylation events and, therefore, modulates the oxidative stress response in yeast.
全基因组分析表明，葡萄酒酵母的启动子区域会发生变化，基因拷贝数也会出现变异，这使得它们与实验室菌株不同，并有助于它们在酿酒过程中更好地适应压力条件，其中氧化应激起着关键作用。由于细胞质硫氧还蛋白II是一种具有硫醇 - 二硫化物氧化还原酶活性的小蛋白，已发现在葡萄酒酵母的生物量繁殖条件下发挥重要功能，因此我们研究了Trx2p在这些菌株氧化应激转录反应的分子调控中的作用。在本研究中，我们分析了由Yap1p或Yap1p与Skn7p合作调控的几种氧化应激相关基因的表达水平。结果显示Trx2p缺陷型菌株中所有测试的Skn7p依赖性基因的表达均降低，并且Trx2p对于葡萄酒酵母呼吸代谢过程中的氧化应激反应至关重要。此外，通过β-半乳糖苷酶测定法检测Yap1p和Skn7p依赖性启动子的活性，清楚地表明Skn7p依赖性启动子的激活受TRX2基因缺陷的影响。最后，我们表明在氧化应激条件下删除TRX2基因会导致Skn7p过度磷酸化。我们提出Trx2p是Skn7p转录因子调控中的一种新的正向效应物，它控制磷酸化事件，从而调节酵母中的氧化应激反应。
