LAUSR

Regulation of Hepatitis C Virus Translation and Infectious Virus Production by the MicroRNA miR-122 A liver-specific microRNA, miR-122, positively regulates hepatitis C virus (HCV) RNA abundance and is essential for production of infectious HCV. Jangra et al. (R. K. Jangra, M. Yi, and S. M. Lemon, J Virol 84:6615– 6625, 2010, https://doi.org/10.1128/JVI.00417 -10) used a genetic approach to show that a higher yield of infectious virus was dependent upon two miR-122-binding sites near the 5= end of the HCV genome, S1 and S2. Viral RNA with base substitutions in both S1 and S2 failed to produce infectious virus in transfected cells, and translation of HCV RNA was reduced over 50% by mutations in either S1 or S2. The authors concluded that miR-122 promotes replication by binding directly to both sites in the genomic RNA and, at least in part, by stimulating internal ribosome entry site (IRES)-mediated translation.