title: MicroRNA-122 dependent binding of Ago2 protein to hepatitis C virus RNA is associated with enhanced RNA stability and translation stimulation.
abstract: Translation of Hepatitis C Virus (HCV) RNA is directed by an internal ribosome entry site (IRES) in the 5'-untranslated region (5'-UTR). HCV translation is stimulated by the liver-specific microRNA-122 (miR-122) that binds to two binding sites between the stem-loops I and II near the 5'-end of the 5'-UTR. Here, we show that Argonaute (Ago) 2 protein binds to the HCV 5'-UTR in a miR-122-dependent manner, whereas the HCV 3'-UTR does not bind Ago2. miR-122 also recruits Ago1 to the HCV 5'-UTR. Only miRNA duplex precursors of the correct length stimulate HCV translation, indicating that the duplex miR-122 precursors are unwound by a complex that measures their length. Insertions in the 5'-UTR between the miR-122 binding sites and the IRES only slightly decrease translation stimulation by miR-122. In contrast, partially masking the miR-122 binding sites in a stem-loop structure impairs Ago2 binding and translation stimulation by miR-122. In an RNA decay assay, also miR-122-mediated RNA stability contributes to HCV translation stimulation. These results suggest that Ago2 protein is directly involved in loading miR-122 to the HCV RNA and mediating RNA stability and translation stimulation.
authors: Institute of Biochemistry, Faculty of Medicine, Justus-Liebig-University, Giessen, Germany.
authors: K Dominik
authors: KD
authors: Conrad
authors: Florian
authors: F
authors: Giering
authors: Corinna
authors: C
authors: Erfurth
authors: Angelina
authors: A
authors: Neumann
authors: Carmen
authors: C
authors: Fehr
authors: Gunter
authors: G
authors: Meister
authors: Michael
authors: M
authors: Niepmann
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics*; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000821:virology; D006367:HeLa Cells; D016174:Hepacivirus / Q000502:physiology*; D006526:Hepatitis C / Q000235:genetics / Q000378:metabolism / Q000821:virology; D006801:Humans; D047468:Immunoprecipitation; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000821:virology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis; D020871:RNA Stability / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014779:Virus Replication
chemical_list: D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; C466422:AGO2 protein, human; D060565:Argonaute Proteins; C531907:MIRN122 microRNA, human; D035683:MicroRNAs; D012367:RNA, Viral