An R-loop is a three-stranded nucleic acid structure that consists of a DNA:RNA hybrid and a displaced strand of DNA. R-loops occur frequently in genomes and have significant physiological importance. They play vital roles in regulating gene expression, DNA replication, and DNA and histone modifications. Several studies have uncovered that R-loops contribute to fundamental biological processes in various organisms. Paradoxically, although they do play essential positive functions required for important biological processes, they can also contribute to DNA damage and genome instability. Recent evidence suggests that R-loops are involved in a number of human diseases, including neurological disorders, cancer, and autoimmune diseases. This review focuses on the molecular basis for R-loop-mediated gene regulation and genomic instability and briefly discusses methods for identifying R-loops in vivo It also highlights recent studies indicating the role of R-loops in DNA double-strand break repair with an updated view of much-needed future goals in R-loop biology.

中文翻译：

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R循环生物学的平衡行为：好，坏和丑陋。

R环是三链核酸结构，由DNA：RNA杂合体和DNA置换链组成。R-环在基因组中频繁发生，并且具有重要的生理重要性。它们在调节基因表达，DNA复制以及DNA和组蛋白修饰中起着至关重要的作用。多项研究发现，R环有助于各种生物的基本生物学过程。矛盾的是，尽管它们确实发挥了重要生物学过程所需的基本正功能，但它们也可能导致DNA损伤和基因组不稳定。最近的证据表明，R环参与许多人类疾病，包括神经系统疾病，癌症和自身免疫性疾病。