Review on circular RNA with protein-coding ability in eukaryotes.

Circular RNA ( circRNA) is a type of endogenous RNA widely expressed in eukaryotic cells, which is formed by back-splicing of pre-RNA without 5'cap and 3'tail. circRNA has long been considered to be without coding ability, for it cannot encode protein and just regulates gene expression as microRNA sponge. However, with more and more research results on circRNA over the years, a small number of circRNAs has been proved able to encode protein or peptides in cap-independent manner. These proteins or peptide have been shown to play a vital role in cellular processes. This paper reviews the current circRNA research, and summarizes some bioinformatics methods related to circRNA protein coding ability. [ABSTRACT FROM AUTHOR]