Heat shock protein 70 is associated with replicase complex of Japanese encephalitis virus and positively regulates viral genome replication

PLoS One. 2013 Sep 23;8(9):e75188. doi: 10.1371/journal.pone.0075188. eCollection 2013.

Abstract

Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that causes the most prevalent viral encephalitis in Asia. The NS5 protein of JEV is a key component of the viral replicase complex, which plays a crucial role in viral pathogenesis. In this study, tandem affinity purification (TAP) followed by mass spectrometry analysis was performed to identify novel host proteins that interact with NS5. Heat shock protein 70 (Hsp70), eukaryotic elongation factor 1-alpha (eEF-1α) and ras-related nuclear protein (Ran) were demonstrated to interact with NS5. In addition to NS5, Hsp70 was also found to interact with NS3 which is another important member of the replicase complex. It was observed that the cytoplasmic Hsp70 partially colocalizes with the components of viral replicase complex including NS3, NS5 and viral dsRNA during JEV infection. Knockdown of Hsp70 resulted in a significantly reduced JEV genome replication. Further analysis reveals that Hsp70 enhances the stability of viral proteins in JEV replicase complex. These results suggest an important role for Hsp70 in regulating JEV replication, which provides a potential target for the development of anti-JEV therapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cricetinae
  • DNA Primers / genetics
  • Encephalitis Virus, Japanese / enzymology*
  • Fluorescent Antibody Technique
  • Gene Knockdown Techniques
  • HEK293 Cells
  • HSP70 Heat-Shock Proteins / genetics
  • HSP70 Heat-Shock Proteins / metabolism*
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Mass Spectrometry
  • Plasmids / genetics
  • RNA Interference
  • RNA, Small Interfering / genetics
  • Real-Time Polymerase Chain Reaction
  • Ubiquitination
  • Viral Nonstructural Proteins / metabolism*
  • Virus Replication / physiology*
  • ran GTP-Binding Protein / metabolism

Substances

  • DNA Primers
  • HSP70 Heat-Shock Proteins
  • NS5 protein, flavivirus
  • RNA, Small Interfering
  • Viral Nonstructural Proteins
  • ran GTP-Binding Protein

Grants and funding

This work was supported by 973 Project of China (2010CB530100), National Natural Sciences Foundation of China (31172325, 81261160325), New Century Excellent Talents in University (NCETNCET-10-0422) and Fundamental Research Funds for the Central Universities (2011PY002). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.