PRMT5: A novel regulator of Hepatitis B virus replication and an arginine methylase of HBV core

PLoS One. 2017 Oct 24;12(10):e0186982. doi: 10.1371/journal.pone.0186982. eCollection 2017.

Abstract

In mammals, protein arginine methyltransferase 5, PRMT5, is the main type II enzyme responsible for the majority of symmetric dimethylarginine formation in polypeptides. Recent study reported that PRMT5 restricts Hepatitis B virus (HBV) replication through epigenetic repression of HBV DNA transcription and interference with encapsidation of pregenomic RNA. Here we demonstrate that PRMT5 interacts with the HBV core (HBc) protein and dimethylates arginine residues within the arginine-rich domain (ARD) of the carboxyl-terminus. ARD consists of four arginine rich subdomains, ARDI, ARDII, ARDIII and ARDIV. Mutation analysis of ARDs revealed that arginine methylation of HBc required the wild-type status of both ARDI and ARDII. Mass spectrometry analysis of HBc identified multiple potential ubiquitination, methylation and phosphorylation sites, out of which lysine K7 and arginines R150 (within ARDI) and R156 (outside ARDs) were shown to be modified by ubiquitination and methylation, respectively. The HBc symmetric dimethylation appeared to be linked to serine phosphorylation and nuclear import of HBc protein. Conversely, the monomethylated HBc retained in the cytoplasm. Thus, overexpression of PRMT5 led to increased nuclear accumulation of HBc, and vice versa, down-regulation of PRMT5 resulted in reduced levels of HBc in nuclei of transfected cells. In summary, we identified PRMT5 as a potent controller of HBc cell trafficking and function and described two novel types of HBc post-translational modifications (PTMs), arginine methylation and ubiquitination.

MeSH terms

  • Hepatitis B virus / enzymology
  • Hepatitis B virus / physiology*
  • Humans
  • Mass Spectrometry
  • Methylation
  • Phosphorylation
  • Protein-Arginine N-Methyltransferases / metabolism*
  • Protein-Arginine N-Methyltransferases / physiology
  • Subcellular Fractions / metabolism
  • Ubiquitination
  • Virus Replication / physiology*

Substances

  • PRMT5 protein, human
  • Protein-Arginine N-Methyltransferases

Grants and funding

This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic (LK11207 to JW) and by the Czech Academy of Sciences (RVO: 61388963, institutional support). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.