Hepatitis C virus core protein interacts with heterogeneous nuclear ribonucleoprotein K

J Biol Chem. 1998 Jul 10;273(28):17651-9. doi: 10.1074/jbc.273.28.17651.

Abstract

Hepatitis C virus (HCV) core protein, a component of viral nucleocapsid, has been shown to modulate cellular and viral promoter activities. To identify potential cellular targets for HCV core protein, a human liver cDNA library was screened for core-interacting proteins using the yeast two-hybrid system. Among the proteins identified was heterogeneous nuclear ribonucleoprotein K (hnRNP K), which has been demonstrated to be a transcriptional regulator. The interaction of HCV core protein with hnRNP K was confirmed by glutathione S-transferase fusion protein binding assay, protein-protein blotting assay, and coimmunoprecipitation in vitro and in vivo. Additionally, these two proteins were shown to be partially colocalized in the nucleus. The hnRNP K-binding site in HCV core protein was mapped to the region from amino acid residues 25-91, a hydrophilic area near the N terminus. The HCV core protein-binding domain was located within amino acid residues 250 to 392, which contain the three proline-rich domains, of hnRNP K. Furthermore, HCV core protein relieved the suppression effect of hnRNP K on the activity of the human thymidine kinase gene promoter. The specific binding of HCV core protein to hnRNP K suggests that multiple functions of hnRNP K may be disrupted by the core protein during HCV infection and thus explains, in part, the pathogenesis of HCV.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Cell Line
  • Cloning, Molecular
  • Cricetinae
  • Cricetulus
  • DNA, Complementary
  • Glutathione Transferase / genetics
  • Heterogeneous-Nuclear Ribonucleoprotein K
  • Heterogeneous-Nuclear Ribonucleoproteins
  • Humans
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA, Heterogeneous Nuclear / metabolism*
  • Recombinant Fusion Proteins / metabolism
  • Ribonucleoproteins / genetics
  • Ribonucleoproteins / metabolism*
  • Thymidine Kinase / genetics
  • Viral Core Proteins / metabolism*

Substances

  • DNA, Complementary
  • Heterogeneous-Nuclear Ribonucleoprotein K
  • Heterogeneous-Nuclear Ribonucleoproteins
  • RNA, Heterogeneous Nuclear
  • Recombinant Fusion Proteins
  • Ribonucleoproteins
  • Viral Core Proteins
  • nucleocapsid protein, Hepatitis C virus
  • Glutathione Transferase
  • Thymidine Kinase