https://orcid.org/0000-0003-2565-9154
Figures & data
Figure 1. Circular RNAs biogenesis
A model shows a pre-mRNA with 4 exons and how different types of circular RNAs are generated. (A) Base-pairing between the two flanking introns, which contain reverse complementary sequences, brings together a downstream 5ʹ ss and an upstream 3ʹ ss and facilitates backsplicing reactions to produce circular RNAs. (B) RBPs binding to the flanking introns can act analogously as flanking complementary sequences to promote backsplicing of circularized exons. (C) Exon skipping generates a mature mRNA and a lariat RNA. Instead of debranching and degradation, the lariat RNA goes for another round of splicing to generate a circular RNA and a double lariat RNA. (D) During canonical splicing, lariat RNAs fail to be debranched and accumulate as circular intronic RNAs (ciRNAs). (E) Some circular RNAs might be products of the intergenic genome region.
Table 1. RBPs involved in circular RNA biogenesis
Figure 2. Circular RNA nuclear export
Once generated, circular RNAs can be fed into different export pathways. Drosophila Hel25E and human UAP56 regulate the nuclear export of long circular RNAs. Human URH49 controls short circular RNA export. YTHDC1 promotes the export of m6A-modified circNSUN2 in human cells.
Figure 3. Circular RNA degradation
A model shows how different types of circular RNAs are degraded. (A) microRNA-mediated circular RNA degradation; (B) m6A-mediated circular RNA degradation; (C) RNase L-mediated circular RNA degradation; (D) GW182-mediated circular RNA degradation; (E) structure-mediated circular RNA degradation.
