title: Differential hepatitis C virus RNA target site selection and host factor activities of naturally occurring miR-122 3΄ variants.
abstract: In addition to suppressing cellular gene expression, certain miRNAs potently facilitate replication of specific positive-strand RNA viruses. miR-122, a pro-viral hepatitis C virus (HCV) host factor, binds and recruits Ago2 to tandem sites (S1 and S2) near the 5΄ end of the HCV genome, stabilizing it and promoting its synthesis. HCV target site selection follows canonical miRNA rules, but how non-templated 3΄ miR-122 modifications impact this unconventional miRNA action is unknown. High-throughput sequencing revealed that a 22 nt miRNA with 3΄G ('22-3΄G') comprised <63% of total miR-122 in human liver, whereas other variants (23-3΄A, 23-3΄U, 21-3΄U) represented 11-17%. All loaded equivalently into Ago2, and when tested individually functioned comparably in suppressing gene expression. In contrast, 23-3΄A and 23-3΄U were more active than 22-3΄G in stabilizing HCV RNA and promoting its replication, whereas 21-3΄U was almost completely inactive. This lack of 21-3΄U HCV host factor activity correlated with reduced recruitment of Ago2 to the HCV S1 site. Additional experiments demonstrated strong preference for guanosine at nt 22 of miR-122. Our findings reveal the importance of non-templated 3΄ miR-122 modifications to its HCV host factor activity, and identify unexpected differences in miRNA requirements for host gene suppression versus RNA virus replication.
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Departments of Medicine and Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7292, USA.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yamane
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Bioinformatics and Computational Biology Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Sara R
authors.initials: SR
authors.lastname: Selitsky
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Shimakami
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Departments of Medicine and Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7292, USA.
authors.forename: You
authors.initials: Y
authors.lastname: Li
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Bioinformatics and Computational Biology Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Mi
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Ishikawa 920-8641, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Honda
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Bioinformatics and Computational Biology Curriculum, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Praveen
authors.initials: P
authors.lastname: Sethupathy
authors.affiliation: Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.|Departments of Medicine and Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7292, USA.
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Lemon
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D060565:Argonaute Proteins / Q000096:biosynthesis / Q000235:genetics*; D001665:Binding Sites; D005786:Gene Expression Regulation / Q000235:genetics; D016174:Hepacivirus / Q000235:genetics* / Q000472:pathogenicity; D006526:Hepatitis C / Q000235:genetics / Q000821:virology; D054884:Host-Pathogen Interactions / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000821:virology; D035683:MicroRNAs / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics; D014779:Virus Replication / Q000235:genetics
chemical_list: D020413:3' Untranslated Regions; C466422:AGO2 protein, human; D060565:Argonaute Proteins; C531907:MIRN122 microRNA, human; D035683:MicroRNAs; D012367:RNA, Viral