Details

Autor(en) / Beteiligte

• Yu, Yingpu
• Scheel, Troels K H
• Luna, Joseph M
• Chung, Hachung
• Nishiuchi, Eiko
• Scull, Margaret A
• Echeverría, Natalia
• Ricardo-Lax, Inna
• Kapoor, Amit
• Lipkin, W Ian
• Divers, Thomas J
• Antczak, Douglas F
• Tennant, Bud C
• Rice, Charles M
• Siddiqui, Aleem

Titel

miRNA independent hepacivirus variants suggest a strong evolutionary pressure to maintain miR-122 dependence

Ist Teil von

• PLoS pathogens, 2017-10, Vol.13 (10), p.e1006694

Ort / Verlag

United States: Public Library of Science

Erscheinungsjahr

2017

Quelle

MEDLINE

Beschreibungen/Notizen

• Hepatitis C virus (HCV) requires the liver specific micro-RNA (miRNA), miR-122, to replicate. This was considered unique among RNA viruses until recent discoveries of HCV-related hepaciviruses prompting the question of a more general miR-122 dependence. Among hepaciviruses, the closest known HCV relative is the equine non-primate hepacivirus (NPHV). Here, we used Argonaute cross-linking immunoprecipitation (AGO-CLIP) to confirm AGO binding to the single predicted miR-122 site in the NPHV 5'UTR in vivo. To study miR-122 requirements in the absence of NPHV-permissive cell culture systems, we generated infectious NPHV/HCV chimeric viruses with the 5' end of NPHV replacing orthologous HCV sequences. These chimeras were viable even in cells lacking miR-122, although miR-122 presence enhanced virus production. No other miRNAs bound this region. By random mutagenesis, we isolated HCV variants partially dependent on miR-122 as well as robustly replicating NPHV/HCV variants completely independent of any miRNAs. These miRNA independent variants even replicate and produce infectious particles in non-hepatic cells after exogenous delivery of apolipoprotein E (ApoE). Our findings suggest that miR-122 independent HCV and NPHV variants have arisen and been sampled during evolution, yet miR-122 dependence has prevailed. We propose that hepaciviruses may use this mechanism to guarantee liver tropism and exploit the tolerogenic liver environment to avoid clearance and promote chronicity.