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目的:本文通过Rnt1p对细胞周期相关mRNAs的作用来探讨RNA的稳定性与细胞周期中细胞壁应激依赖调控之间的关系。方法:用定量RT-PCR分析Rnt1 mRNA的表达水平;用酵母细胞的免疫荧光标记检测Swi4p-和Hsl1p-GFP的融合蛋白;用扫描式分光光度计检测细胞的生长过程。结果:1)酵母细胞核Rnt1p直接裂解细胞周期调控相关基因的mRNAs;2)RNT1的缺失改变了Hsl1p水平和细胞的定位;3)HSL1的过表达引起RNT1缺失表型的部分复制;4)HSL1的缺失部分地抑制了rnt1△细胞表型的缺陷。在这些基因调控模型中细胞核mRNA的降解加强了细胞应激反应与细胞周期之间的连系。结论:细胞核mRNA的选择性降解不仅需要细胞壁的应激反应也需要细胞壁完整性检查点的调控,酵母细胞核Rnt1p的缺失增加了和形态发生检查点及细胞壁整体通路都相关的mRNAs表达,最终导致应激反应的减弱。
OBJECTIVE: To investigate the relationship between the stability of RNA and the regulation of cell wall stress-dependent cell cycle by the effect of Rnt1p on cell cycle related mRNAs. Methods: The expression of Rnt1 mRNA was analyzed by quantitative RT-PCR. The fusion protein of Swi4p- and Hsl1p-GFP was detected by immunofluorescence staining with yeast cells. The growth of cells was detected by scanning spectrophotometer. Results: 1) Rnt1p directly cleaves mRNAs of cell cycle related genes in yeast cell nucleus; 2) deletion of RNT1 alters Hsl1p level and cell location; 3) HSL1 overexpression causes partial replication of RNT1 deletion phenotype; 4) Deletion partially suppresses the defects of the rnt1 Δ cell phenotype. Degradation of nuclear mRNAs in these gene regulatory models enhances the link between cellular stress response and cell cycle. CONCLUSIONS: The selective degradation of nuclear mRNA not only requires cell wall stress but also cell wall integrity checkpoint control. The deletion of yeast Rnt1p increases the expression of mRNAs associated with both morphological checkpoints and cell wall integral pathways, resulting in Decreased shock response.