The new function of circRNA: translation.

Circular RNAs (circRNAs) have been considered a special class of non-coding RNAs without 5' caps and 3' tails which are covalently closed RNA molecules generated by back splicing of mRNA. For a long time, circRNAs have been considered to be directly involved in various biological processes as functional RNA. In recent years, a variety of circRNAs have been found to have translational functions, and the resultant peptides also play biological roles in the emergence and progression of human disease. The discovery of these circRNAs and their encoded peptides has enriched genomics, helped us to study the causes of diseases, and promoted the development of biotechnology. The purpose of this review is to summarize the research progress of the detection methods, translation initiation mechanism, as well as functional mechanism of peptides encoded by circRNAs, with the goal of providing the directions for the discovery of biomarkers for diagnosis, prognosis, and therapeutic targets for human disease.