The emerging recognition of the functional roles of circular RNAs (circRNAs) has given rise to a new perspective regarding our understanding of cellular physiology and disease pathogenesis. Unlike linear RNAs, circRNAs are covalently closed continuous loops that act as gene regulators in mammals, and their sequence composition determines the mode of circRNA biogenesis. The availability and integrated use of advanced genome analysis platforms have allowed the identification of a large number of these molecules. Their high abundance, stability and evolutionary conservation among species endow circRNAs with numerous potential functions, such as acting as microRNA (miRNA) sponges or binding to RNA-associated proteins to form RNA-protein complexes that regulate gene transcription. Moreover, circRNAs have been shown to be expressed in a tissue-specific manner and in pathological conditions, which has stimulated significant interest in their role in human disease and cancer. In this concise review, we outline the characteristics, functions and mechanisms of action of circRNAs as well as their involvement in different diseases. Although their exact roles and mechanisms of gene regulation remain to be clarified, circRNAs have potential applications as disease biomarkers and novel therapeutic targets.

环状RNA（circRNA）的功能作用的新兴认识已引起有关我们对细胞生理学和疾病发病机制的理解的新观点。与线性RNA不同，circRNA是共价闭合的连续环，在哺乳动物中起着基因调节剂的作用，其序列组成决定了circRNA生物发生的模式。先进的基因组分析平台的可用性和综合使用已允许鉴定大量这些分子。它们在物种中的高丰度，稳定性和进化保守性赋予circRNA具有许多潜在功能，例如充当microRNA（miRNA）海绵或与RNA相关蛋白结合形成调节基因转录的RNA蛋白复合物。而且，已经证明circRNA以组织特异性方式和在病理条件下表达，这引起了人们对其在人类疾病和癌症中的作用的极大兴趣。在这篇简明的综述中，我们概述了circRNA的特征，功能和作用机制，以及它们参与不同疾病的过程。尽管其确切的作用和基因调控的机制尚待阐明，但是circRNAs作为疾病生物标记物和新型治疗靶标具有潜在的应用。