Circular RNAs: New Players in Gene Regulation

The existence of circular RNAs (circRNAs) was demonstrated over 30 years ago. They did not gain much interest at the time because they appeared to be relatively rare when compared to the abundance of the canonical linear RNAs. However, more recent evidence suggests that circRNAs are abundant in cells and tissues and possess intriguing biological properties. These recent developments have renewed our interest in this novel class of molecules. This report will provide an overview of circRNAs, discuss how they may modify our understanding of gene regulation and indicate their most likely relevance to health. The circRNAs from viruses, bacteria and archaea are not in the scope of this report, and we focused this review on circRNAs in eukaryotes.