Kobayashi Takehiko, Sasaki Mariko
FEMS Yeast Res. 2017 Jan 1;17(1). doi: 10.1093/femsyr/fox001.
The ribosomal RNA gene (rDNA) is the most abundant gene in yeast and other eukaryotic organisms. Due to its heavy transcription, repetitive structure and programmed replication fork pauses, the rDNA is one of the most unstable regions in the genome. Thus, the rDNA is the best region to study the mechanisms responsible for maintaining genome integrity. Recently, we screened a library of ∼4800 budding yeast gene knockout strains to identify mutants defective in the maintenance of rDNA stability. The results of this screen are summarized in the Yeast rDNA Stability (YRS) Database, in which the stability and copy number of rDNA in each mutant are presented. From this screen, we identified ∼700 genes that may contribute to the maintenance of rDNA stability. In addition, ∼50 mutants had abnormally high or low rDNA copy numbers. Moreover, some mutants with unstable rDNA displayed abnormalities in another chromosome. In this review, we introduce the YRS Database and discuss the roles of newly identified genes that contribute to rDNA maintenance and genome integrity.
核糖体RNA基因（rDNA）是酵母和其他真核生物中含量最丰富的基因。由于其转录活跃、结构重复以及程序性复制叉停顿，rDNA是基因组中最不稳定的区域之一。因此，rDNA是研究维持基因组完整性机制的最佳区域。最近，我们筛选了一个约4800个芽殖酵母基因敲除菌株的文库，以鉴定在维持rDNA稳定性方面存在缺陷的突变体。该筛选结果总结在酵母rDNA稳定性（YRS）数据库中，其中展示了每个突变体中rDNA的稳定性和拷贝数。通过该筛选，我们鉴定出约700个可能有助于维持rDNA稳定性的基因。此外，约50个突变体的rDNA拷贝数异常高或低。而且，一些rDNA不稳定的突变体在另一条染色体上表现出异常。在这篇综述中，我们介绍了YRS数据库，并讨论了新鉴定的有助于rDNA维持和基因组完整性的基因的作用。
