Heterochromatin is the transcriptionally repressed portion of eukaryotic chromatin that maintains a condensed appearance throughout the cell cycle. At sites of ribosomal DNA (rDNA) heterochromatin, epigenetic states contribute to gene silencing and genome stability, which are required for proper chromosome segregation and a normal life span. Here, we focus on recent advances in the epigenetic regulation of rDNA silencing in Saccharomyces cerevisiae and in mammals, including regulation by several histone modifications and several protein components associated with the inner nuclear membrane within the nucleolus. Finally, we discuss the perturbations of rDNA epigenetic pathways in regulating cellular aging and in causing various types of diseases.

中文翻译：

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核糖体DNA沉默的表观遗传途径。

异染色质是真核染色质的转录抑制部分，在整个细胞周期中都保持浓缩的外观。在核糖体DNA（rDNA）异染色质的位点，表观遗传状态有助于基因沉默和基因组稳定，这是正确染色体分离和正常寿命所必需的。在这里，我们专注于酿酒酵母和哺乳动物中rDNA沉默的表观遗传调控的最新进展，包括通过几个组蛋白修饰和与核仁内核膜相关的几个蛋白质成分的调控。最后，我们讨论了rDNA表观遗传途径在调节细胞衰老和引起各种疾病中的摄动。