School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong
Proc Natl Acad Sci U S A. 2019 Mar 26;116(13):6270-6279. doi: 10.1073/pnas.1821384116. Epub 2019 Mar 8.
In budding yeast, which possesses simple point centromeres, we discovered that all of its centromeres express long noncoding RNAs (cenRNAs), especially in S phase. Induction of cenRNAs coincides with CENP-A loading time and is dependent on DNA replication. Centromeric transcription is repressed by centromere-binding factor Cbf1 and histone H2A variant H2A.Z Deletion of and results in an up-regulation of cenRNAs; an increased loss of a minichromosome; elevated aneuploidy; a down-regulation of the protein levels of centromeric proteins CENP-A, CENP-A chaperone HJURP, CENP-C, Survivin, and INCENP; and a reduced chromatin localization of CENP-A, CENP-C, and Aurora B When the RNA interference system was introduced to knock down all cenRNAs from the endogenous chromosomes, but not the cenRNA from the circular minichromosome, an increase in minichromosome loss was still observed, suggesting that cenRNA functions to regulate centromere activity. CenRNA knockdown partially alleviates minichromosome loss in , , and in a dose-dependent manner, demonstrating that cenRNA level is tightly regulated to epigenetically control point centromere function.
在芽殖酵母中,其具有简单的点状着丝粒,我们发现所有的着丝粒都表达长非编码 RNA(cenRNA),尤其是在 S 期。cenRNA 的诱导与 CENP-A 加载时间一致,并且依赖于 DNA 复制。着丝粒转录受到着丝粒结合因子 Cbf1 和组蛋白 H2A 变体 H2A.Z 的抑制。缺失 和 导致 cenRNA 的上调;微染色体的丢失增加;非整倍体增加;着丝粒蛋白 CENP-A、CENP-A 伴侣 HJURP、CENP-C、Survivin 和 INCENP 的蛋白水平下调;以及 CENP-A、CENP-C 和 Aurora B 的染色质定位减少。当引入 RNA 干扰系统从内源性染色体上敲低所有 cenRNA,但不敲低环状微染色体上的 cenRNA 时,仍观察到微染色体丢失增加,表明 cenRNA 功能 调节着丝粒活性。cenRNA 敲低以剂量依赖的方式部分缓解 、 、 中的微染色体丢失,表明 cenRNA 水平受到严格调控,以表观遗传方式控制着丝粒功能。