Editing RNA splicing (section)

== Splicing and genesis of circRNAs ==
The existence of backsplicing was first suggested in 2012.<ref> Salzman J, Gawad C, Wang PL, et al. Circular RNAs are the predominant transcript isoform from hundreds of human genes in diverse cell types. PLoS One 2012;7(2):e30733.</ref> This backsplicing explains the genesis of circular RNAs resulting from the exact junction between the 3' boundary of an exon with the 5' boundary of an exon located upstream.<ref> Jeck WR, Sorrentino JA, Wang K, et al. Circular RNAs are abundant, conserved, and associated with ALU repeats. RNA 2013;19(2):141-57.</ref> In these exonic circular RNAs, the junction is a classic 3'-5'link.

The exclusion of intronic sequences during splicing can also leave traces, in the form of circular RNAs.<ref> Zhang Y, Zhang XO, Chen T, et al. Circular intronic long noncoding RNAs. Molecular cell 2013;51(6):792-806.</ref> In some cases, the intronic lariat is not destroyed and the circular part remains as a lariat-derived circRNA<ref> Talhouarne GJ and Gall JG. Lariat intronic RNAs in the cytoplasm of Xenopus tropicalis oocytes. RNA 2014;20(9):1476-87. </ref>.In these lariat-derived circular RNAs, the junction is a 2'-5'link.