Essential Role of Domain III of Nonstructural Protein 5A for Hepatitis C Virus Infectious Particle Assembly

PLoS Pathogens

Nicole Appel¹  Ralf Bartenschlager¹  Jacomine Krijnse-Locker¹  Peter Friebe¹  Torsten Schaller¹  Sven Miller¹  Ulrike Engel¹  Margarita Zayas¹  Stephanie Kallis¹ 

[1] Department of Molecular Virology, University of Heidelberg, Heidelberg, Germany

关键词: Viral core;    Viral replication;    Transfection;    Deletion mutagenesis;    Hepatitis C virus;    RNA viruses;    Viral genomics;    Luciferase assay;   

DOI  :  10.1371/journal.ppat.1000035

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Persistent infection with the hepatitis C virus (HCV) is a major risk factor for the development of liver cirrhosis and hepatocellular carcinoma. With an estimated about 3% of the world population infected with this virus, the lack of a prophylactic vaccine and a selective therapy, chronic hepatitis C currently is a main indication for liver transplantation. The establishment of cell-based replication and virus production systems has led to first insights into the functions of HCV proteins. However, the role of nonstructural protein 5A (NS5A) in the viral replication cycle is so far not known. NS5A is a membrane-associated RNA-binding protein assumed to be involved in HCV RNA replication. Its numerous interactions with the host cell suggest that NS5A is also an important determinant for pathogenesis and persistence. In this study we show that NS5A is a key factor for the assembly of infectious HCV particles. We specifically identify the C-terminal domain III as the primary determinant in NS5A for particle formation. We show that both core and NS5A colocalize on the surface of lipid droplets, a proposed site for HCV particle assembly. Deletions in domain III of NS5A disrupting this colocalization abrogate infectious particle formation and lead to an enhanced accumulation of core protein on the surface of lipid droplets. Finally, we show that mutations in NS5A causing an assembly defect can be rescued by trans-complementation. These data provide novel insights into the production of infectious HCV and identify NS5A as a major determinant for HCV assembly. Since domain III of NS5A is one of the most variable regions in the HCV genome, the results suggest that viral isolates may differ in their level of virion production and thus in their level of fitness and pathogenesis.

【 授权许可】

CC BY