Fig. 2From: Circles reshaping the RNA world: from waste to treasureComposition of three types circRNAs. Legend: CircRNAs are generated in the process of the skip splicing of pre-mRNA and compete with the linear transcription, they are generally classified into three types focusing on their components. (1) EcircRNAs comprise exons and are the most common circRNAs. (2) CiRNAs are composed by two or more connected introns and are detected rare in eukaryocyte. (3) EIciRNAs are circularized with introns ‘retained’ between the exons and play a part in gene regulationBack to article page