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Fu-Tao Zhao, Yun Zhou, Yong-Xing Zhou, Qun Yang, Le Song, Xiao-Jing Jiang, Zhan-Sheng Jia
(State Key Discipline and Center for Infectious Diseases, Tangdu Hospital Affiliated to the Fourth Military Medical University, Xi’an, Shaanxi, China (mainland))
Med Sci Monit 2015; 21:980-986
Liver-specific microRNA (miR)-122 has been shown to be involved in regulating translation of hepatitis C viral (HCV) RNA. This study aimed to explore the molecular mechanism of miR-122 in regulating HCV RNA translation initiation.
Material and Methods: In human liver hepatocellular carcinoma cell line HepG2, UV cross-link assay was performed on a large scale to identify RNA-binding proteins with gradient concentrations of miR-122. Analytical ultracentrifugation was then used to separate the translation initiation complexes. All RNA-binding proteins were then identified by Western blotting.
Results: The binding of 68 kDa protein (p68) to HCV RNA was suppressed by the addition of miR-122 via the competitive binding assay. Such inhibition can be eliminated by the addition of 2’-O-methylated oligonucleotides. This binding suppression was determined to be specific for miR-122, which used the mature single-stranded RNA to suppress the binding of p68 onto HCV RNA. This binding inhibition was further validated by using authentic miR-122 with conserved regions and mutated sequences.
Conclusions: The binding of p68 onto HCV RNA can be specifically inhibited by miR-122 via a competitive binding process.