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Hepatitis C Virus Nonstructural Protein NS3 Binds to Sm‐D1, a Small Nuclear Ribonucleoprotein Associated with Autoimmune Disease
Author(s) -
Iwai Atsushi,
Hasumura Yasushi,
Nojima Takayuki,
Takegami Tsutomu
Publication year - 2003
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2003.tb03423.x
Subject(s) - ns3 , biology , ribonucleoprotein , virology , microbiology and biotechnology , hepatitis c virus , virus , biochemistry , rna , gene
Hepatitis C virus (HCV) causes a persistent infection, chronic hepatitis, and leads to hepatocellular carcinoma. Nonstructural protein 3 (NS3) of HCV possesses protease, nucleoside triphosphatase, and helicase activities. Using the yeast two hybrid assay, we identified Sm‐D1, a host protein that binds to NS3. Sm‐D1 is a component of small nuclear ribonucleoprotein (snRNP) complexes which are associated with autoimmune disease. Sm‐D1 has Gly‐Arg (GR) repeats at the C terminus, which contains dimethylarginine modified by post‐translational modification and may constitute an immunoreactive determinant. Deletion mutants revealed that the C‐terminal region of Sm‐D1 containing the GR repeats was the binding region for NS3, and the expression feature of Sm‐D1 was affected by co‐expression of NS3. Immunostaining assay demonstrated that NS3 was also present in the nucleus of cells overexpressing Sm‐D1, although it was usually found in cytoplasm. The localization of NS3 could change following interaction with Sm‐D1 and affect the function of Sm‐D1.