Multifaceted roles of complementary sequences on circRNA formation  

作　　者：Qin Yang Ying Wang Li Yang 

机构地区：[1]CAS Key Laboratory of Computational Biology, Collaborative Innovation Center of Genetics and Development, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences University of Chinese Academy of Sciences, Shanghai 200031, China [2]School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China

出　　处：《Frontiers of Electrical and Electronic Engineering in China》2017年第3期205-209,共5页中国电气与电子工程前沿（英文版）

摘　　要：Background： Circular RNAs （circRNAs） from back-spliced exon（s） are characterized by the covalently closed loop feature with neither 5＇ to 3＇ polarity nor polyadenylated tail. By using specific computational approaches that identify reads mapped to back-splice junctions with a reversed genomic orientation, ten thousands of cireRNAs have been recently re-identified in various cell lines/tissues and across different species. Increasing lines of evidence suggest that back-splicing is catalyzed by the canonical spliceosomal machinery and modulated by cis-elements and trans-factors. Results： In this mini-review, we discuss our current understanding of circRNA biogenesis regulation, mainly focusing on the complex regulation of complementary sequences, especially Alus in human, on circRNA formation. Conclusions： Back-splicing can be significantly facilitated by RNA pair formed by orientation-opposite complementary sequences that juxtapose flanking introns of circularized exon（s）. RNA pair formed within individual introns competes with RNA pair formed across flanking introns in the same gene locus, leading to distinct choices for either canonical splicing or back-splicing. Multiple RNA pairs that bracket different circle-forming exons compete for alternative back-splicing selection, resulting in multiple circRNAs generated in a single gene locus.Background： Circular RNAs （circRNAs） from back-spliced exon（s） are characterized by the covalently closed loop feature with neither 5＇ to 3＇ polarity nor polyadenylated tail. By using specific computational approaches that identify reads mapped to back-splice junctions with a reversed genomic orientation, ten thousands of cireRNAs have been recently re-identified in various cell lines/tissues and across different species. Increasing lines of evidence suggest that back-splicing is catalyzed by the canonical spliceosomal machinery and modulated by cis-elements and trans-factors. Results： In this mini-review, we discuss our current understanding of circRNA biogenesis regulation, mainly focusing on the complex regulation of complementary sequences, especially Alus in human, on circRNA formation. Conclusions： Back-splicing can be significantly facilitated by RNA pair formed by orientation-opposite complementary sequences that juxtapose flanking introns of circularized exon（s）. RNA pair formed within individual introns competes with RNA pair formed across flanking introns in the same gene locus, leading to distinct choices for either canonical splicing or back-splicing. Multiple RNA pairs that bracket different circle-forming exons compete for alternative back-splicing selection, resulting in multiple circRNAs generated in a single gene locus.

关 键 词：circRNA circRNA biogenesis back-splicing CIS-ELEMENTS complementary sequences ALU 

分 类 号：Q522[生物学—生物化学] TN911.21[电子电信—通信与信息系统]