Hepatitis C virus core protein interacts with heterogeneous nuclear ribonucleoprotein K.
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.
Hsieh
T Y
TY
Department of Molecular Microbiology and Immunology, University of Southern California School of Medicine, Los Angeles, California 90033-1054, USA.
Matsumoto
M
M
Chou
H C
HC
Schneider
R
R
Hwang
S B
SB
Lee
A S
AS
Lai
M M
MM
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary; D005982:Glutathione Transferase / Q000235:genetics; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D013937:Thymidine Kinase / Q000235:genetics; D014758:Viral Core Proteins / Q000378:metabolism*
D018076:DNA, Complementary; D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D012332:RNA, Heterogeneous Nuclear; D011993:Recombinant Fusion Proteins; D012261:Ribonucleoproteins; D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus; D005982:Glutathione Transferase; D013937:Thymidine Kinase