title: Insights into circular RNA biology.
abstract: Circular RNAs (circRNAs) are a novel class of non-coding RNA characterized by a covalently closed-loop structure generated through a special type of alternative splicing termed backsplicing. CircRNAs are emerging as a heterogeneous class of molecules involved in modulating gene expression by regulation of transcription, protein and miRNA functions. CircRNA expression is cell type and tissue specific and can be largely independent of the expression level of the linear host gene, indicating that regulation of expression might be an important aspect with regard to control of circRNA function. In this review, a brief introduction to the characteristics that define a circRNA will be given followed by a discussion of putative biogenesis pathways and modulators of circRNA expression as well as of the stage at which circRNA formation takes place. A brief summary of circRNA functions will also be provided and lastly, an outlook with a focus on unanswered questions regarding circRNA biology will be included.
authors.affiliation: a Department of Molecular Biology and Genetics (MBG) and Aarhus University , Aarhus , Denmark.|b Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , Aarhus , Denmark.
authors.forename: Karoline K
authors.initials: KK
authors.lastname: Ebbesen
authors.affiliation: a Department of Molecular Biology and Genetics (MBG) and Aarhus University , Aarhus , Denmark.
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Hansen
authors.affiliation: a Department of Molecular Biology and Genetics (MBG) and Aarhus University , Aarhus , Denmark.|b Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , Aarhus , Denmark.
authors.forename: Jørgen
authors.initials: J
authors.lastname: Kjems
mesh_terms: D021581:Active Transport, Cell Nucleus; D017398:Alternative Splicing; D000818:Animals; D020029:Base Pairing; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D006801:Humans; D055029:Inverted Repeat Sequences; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D012313:RNA / Q000235:genetics* / Q000378:metabolism; D017393:RNA Editing; D022821:RNA Splice Sites; D000079962:RNA, Circular; D017381:Spliceosomes / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome
chemical_list: D035683:MicroRNAs; D022821:RNA Splice Sites; D000079962:RNA, Circular; D012313:RNA
keywords: Alternative splicing; backsplicing; biogenesis; circRNA; circular RNA; inverted repeats