The human ribosomal DNA (rDNA) locus encodes a variety of long non-coding RNAs (lncRNAs). Among them, the canonical ribosomal RNAs that are the catalytic components of the ribosomes, as well as regulatory lncRNAs including promoter-associated RNAs (pRNA), stress-induced promoter and pre-rRNA antisense RNAs (PAPAS), and different intergenic spacer derived lncRNA species (IGSRNA). In addition, externally encoded lncRNAs are imported into the nucleolus, which orchestrate the complex regulation of the nucleolar state in normal and stress conditions via a plethora of molecular mechanisms. This review focuses on the triplex and R-loop formation aspects of lncRNAs at the rDNA locus in yeast and human cells. We discuss the protein players that regulate R-loops at rDNA and how their misregulation contributes to DNA damage and disease. Furthermore, we speculate how DNA lesions such as rNMPs or 8-oxo-dG might affect RNA–DNA hybrid formation. The transcription of lncRNA from rDNA has been observed in yeast, plants, flies, worms, mouse and human cells. This evolutionary conservation highlights the importance of lncRNAs in rDNA function and maintenance.

人核糖体DNA（rDNA）基因座编码多种长的非编码RNA（lncRNA）。其中，作为核糖体催化成分的经典核糖体RNA，以及调控型lncRNA，包括启动子相关RNA（pRNA），应激诱导的启动子和pre-rRNA反义RNA（PAPAS），以及不同的基因间隔子衍生的lncRNA种（IGSRNA）。此外，外部编码lncRNAs被导入到核仁，其编排核仁状态的复杂的调节在正常和应激条件通过过多的分子机制。这篇评论集中在酵母和人类细胞中rDNA基因座上lncRNA的三链体和R环形成方面。我们讨论了调节rDNA上R环的蛋白分子，以及它们的失调如何导致DNA损伤和疾病。此外，我们推测DNA损伤（例如rNMPs或8-oxo-dG）如何影响RNA-DNA杂种的形成。已经在酵母，植物，果蝇，蠕虫，小鼠和人细胞中观察到了来自rDNA的lncRNA的转录。这种进化的保守性突出了lncRNA在rDNA功能和维持中的重要性。