title: Circular RNAs: diversity of form and function.
abstract: It is now clear that there is a diversity of circular RNAs in biological systems. Circular RNAs can be produced by the direct ligation of 5' and 3' ends of linear RNAs, as intermediates in RNA processing reactions, or by "backsplicing," wherein a downstream 5' splice site (splice donor) is joined to an upstream 3' splice site (splice acceptor). Circular RNAs have unique properties including the potential for rolling circle amplification of RNA, the ability to rearrange the order of genomic information, protection from exonucleases, and constraints on RNA folding. Circular RNAs can function as templates for viroid and viral replication, as intermediates in RNA processing reactions, as regulators of transcription in cis, as snoRNAs, and as miRNA sponges. Herein, we review the breadth of circular RNAs, their biogenesis and metabolism, and their known and anticipated functions.
authors.affiliation: Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, Colorado 80309, USA.
authors.forename: Erika
authors.initials: E
authors.lastname: Lasda
authors.affiliation: Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of Colorado, Boulder, Colorado 80309, USA roy.parker@colorado.edu.
authors.forename: Roy
authors.initials: R
authors.lastname: Parker
mesh_terms: D007438:Introns / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics; D009690:Nucleic Acid Conformation; D012313:RNA / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D022821:RNA Splice Sites / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics*; D000079962:RNA, Circular; D014772:Viroids / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics*
chemical_list: D035683:MicroRNAs; D022821:RNA Splice Sites; D000079962:RNA, Circular; D012313:RNA
keywords: backsplicing; circRNA; circular RNA; intermediates; intron; nonlinear; splicing