title: Ago-2-mediated slicer activity is essential for anti-flaviviral efficacy of RNAi.
abstract: RNA interference can be mediated by fully complementary siRNA or partially complementary miRNA. siRNAs are widely used to suppress viral replication and the fully complementary siRNA bound Ago-2 in the RISC is known to degrade the target RNA. Although other argonaute proteins lacking slicer activity can also bind oligonucleotides with both si and miRNA structures, whether they can also contribute to antiviral effects is not entirely clear. We tested si and miRNA structured oligos for target repression in dual luciferase assays as well as for inhibition of Dengue and West Nile virus replication in ES cells expressing individual Ago proteins. In luciferase assays, both fully complementary and partially complementary oligos effectively repressed their targets in all individual Ago expressing cell lines, although the efficacy with fully complementary oligos was higher in Ago-2+ cells. However, partially complementary oligos had no effect on virus replication in any cell line, while fully complementary siRNAs were highly effective in Ago-2 expressing, but not in cells expressing other Ago proteins. This occurred irrespective of whether the target sequences were located in the coding region or 3'UTR of the virus. We conclude that Ago-2 slicer activity is essential for anti-viral efficacy of siRNAs and miRNA-mediated translational repression/transcript destabilization is too weak to suppress the abundantly expressed flaviviral proteins.
authors.affiliation: Department of Biomedical Sciences, Center of Excellence in Infectious Disease Research, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, United States of America.
authors.forename: Shuiping
authors.initials: S
authors.lastname: Chen
authors.forename: Harendra S
authors.initials: HS
authors.lastname: Chahar
authors.forename: Sojan
authors.initials: S
authors.lastname: Abraham
authors.forename: Haoquan
authors.initials: H
authors.lastname: Wu
authors.forename: Theodore C
authors.initials: TC
authors.lastname: Pierson
authors.forename: Xiaozhong A
authors.initials: XA
authors.lastname: Wang
authors.forename: N
authors.initials: N
authors.lastname: Manjunath
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000998:Antiviral Agents / Q000494:pharmacology*; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003715:Dengue; D003716:Dengue Virus / Q000235:genetics*; D053595:Embryonic Stem Cells / Q000821:virology; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D009841:Oligonucleotides / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics*; D014779:Virus Replication; D014901:West Nile Fever; D014902:West Nile virus / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D000998:Antiviral Agents; D060565:Argonaute Proteins; D035683:MicroRNAs; D009841:Oligonucleotides; D034741:RNA, Small Interfering; D008156:Luciferases
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