Fig. 1
From: Expanding uncapped translation and emerging function of circular RNA in carcinomas and noncarcinomas
Biogenesis and function of various circular RNAs. Circular RNAs are the product of back splicing of pre-messenger RNAs (pre-mRNAs), comprising intronic circRNA (ciRNA) from intron (A), Exonic and intronic circRNA (EIciRNA) from exon covering intronic regions (B), exon circRNA (EcircRNA) from exons in nuclear (C) and mitochondrial genomes (mecciRNAs) (D), read-through circRNA (rt-CircRNA) from exons between neighboring genes on the same strand (E), and fused circRNA (f-circRNA) fuse from exons between two distant genes (F). CiRNA interacts with small nuclear ribonucleoprotein (snRNP) to enhance transcription rate of its host gene (G). EIciRNA can be a scaffold to recruit functional molecules (H). EcircRNAs are exported to cytoplasm as the sponges of micro-RNA (I) and protein (J), or as the templates to be translated into novel protein (K). MecciRNA may be linked to an inhibition of Reactive oxygen species-ROS (L). F-circRNA accompanied with fused protein to promote tumorigenesis (M)