Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8021, Japan.
Department of Science, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka, 422-8021, Japan.
Biochem Biophys Res Commun. 2022 Jun 30;611:46-52. doi: 10.1016/j.bbrc.2022.04.078. Epub 2022 Apr 20.
When asynchronously growing cells suffer from nutrient depletion and inactivation of target of rapamycin complex 1 (TORC1) protein kinase, the rDNA (rRNA gene) region is condensed in budding yeast Saccharomyces cerevisiae, which is executed by condensin and Cdc14 protein phosphatase. However, it is unknown whether these mitotic factors can condense the rDNA region in nutrient-starved interphase cells. Here, we show that condensin is not involved in TORC1 inactivation-induced rDNA condensation in G1 cells. Instead, the high-mobility group protein Hmo1 drove this process. The histone deacetylase Rpd3 and Cdc14, which repress rRNA transcription, were both required for the interphase rDNA condensation. Furthermore, interphase rDNA condensation necessitated CLIP and cohibin that tether rDNA to inner nuclear membranes. Finally, we showed that Hmo1, CLIP, Rpd3, and Cdc14 were required for survival in nutrient-starved G1 cells. Thus, this study disclosed novel features of interphase chromosome condensation.
当异步生长的细胞遭受营养物质枯竭和雷帕霉素靶蛋白激酶复合物 1（TORC1）蛋白激酶失活时，酿酒酵母（Saccharomyces cerevisiae）的 rDNA（rRNA 基因）区域会发生凝聚，这一过程由凝聚蛋白和 Cdc14 蛋白磷酸酶执行。然而，尚不清楚这些有丝分裂因子是否可以在营养饥饿的间期中凝聚 rDNA 区域。在这里，我们发现，TORC1 失活诱导的 G1 细胞中 rDNA 凝聚不涉及凝聚蛋白。相反，高迁移率族蛋白 Hmo1 驱动了这个过程。组蛋白去乙酰化酶 Rpd3 和 Cdc14 抑制 rRNA 转录，这两者对于间期 rDNA 凝聚都是必需的。此外，间期 rDNA 凝聚需要 CLIP 和 cohibin 将 rDNA 固定在内核膜上。最后，我们表明 Hmo1、CLIP、Rpd3 和 Cdc14 对于营养饥饿的 G1 细胞的存活是必需的。因此，本研究揭示了间期染色体凝聚的新特征。
