TGF-β suppression of HBV RNA through AID-dependent recruitment of an RNA exosome complex

PLoS Pathog. 2015 Apr 2;11(4):e1004780. doi: 10.1371/journal.ppat.1004780. eCollection 2015 Apr.

Abstract

Transforming growth factor (TGF)-β inhibits hepatitis B virus (HBV) replication although the intracellular effectors involved are not determined. Here, we report that reduction of HBV transcripts by TGF-β is dependent on AID expression, which significantly decreases both HBV transcripts and viral DNA, resulting in inhibition of viral replication. Immunoprecipitation reveals that AID physically associates with viral P protein that binds to specific virus RNA sequence called epsilon. AID also binds to an RNA degradation complex (RNA exosome proteins), indicating that AID, RNA exosome, and P protein form an RNP complex. Suppression of HBV transcripts by TGF-β was abrogated by depletion of either AID or RNA exosome components, suggesting that AID and the RNA exosome involve in TGF-β mediated suppression of HBV RNA. Moreover, AID-mediated HBV reduction does not occur when P protein is disrupted or when viral transcription is inhibited. These results suggest that induced expression of AID by TGF-β causes recruitment of the RNA exosome to viral RNP complex and the RNA exosome degrades HBV RNA in a transcription-coupled manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • APOBEC Deaminases
  • Blotting, Western
  • Cell Line
  • Cytidine Deaminase / metabolism*
  • Cytosine Deaminase / metabolism
  • Exosome Multienzyme Ribonuclease Complex / metabolism*
  • Hepatitis B / genetics
  • Hepatitis B virus / physiology*
  • Humans
  • Immunoprecipitation
  • Polymerase Chain Reaction
  • RNA, Viral / genetics*
  • RNA, Viral / metabolism
  • Transfection
  • Transforming Growth Factor beta / metabolism*
  • Virus Replication / physiology

Substances

  • RNA, Viral
  • Transforming Growth Factor beta
  • Exosome Multienzyme Ribonuclease Complex
  • AICDA (activation-induced cytidine deaminase)
  • Cytosine Deaminase
  • APOBEC Deaminases
  • APOBEC3 proteins, human
  • Cytidine Deaminase

Grants and funding

This study was supported by the Founding Program for Next Generation World-Leading Researchers, and a Grant-in-Aid for Young Scientists (B) from the Ministry of Education, Science, Sports, and Culture of Japan, and the Hokkoku Foundation for Cancer Research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.