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

PLoS Pathogens

Bud C. Tennant¹  Douglas F. Antczak²  Joseph M. Luna³  Charles M. Rice⁴  Thomas J. Divers⁵  Amit Kapoor⁶  Eiko Nishiuchi⁷  Natalia Echeverría⁷  Troels K. H. Scheel⁷  Margaret A. Scull⁷  Hachung Chung⁷  Ian W. Lipkin⁷  Yingpu Yu⁷  Inna Ricardo-Lax⁷ 

[1] Center for Infection and Immunity, Mailman School of Public Health and College of Physicians & Surgeons, Columbia University, New York, NY, United States of America;Center for Vaccines and Immunity, The Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States of America;Copenhagen Hepatitis C Program, Department of Infectious Diseases, Hvidovre Hospital, and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark;Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States of America;Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States of America;Laboratorio de Virología Molecular, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay;Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, United States of America

关键词: MicroRNAs;    Hepacivirus;    Viral replication;    5' UTR;    Transfection;    293T cells;    Hepatitis C virus;    Cell binding;   

DOI  :  10.1371/journal.ppat.1006694

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY