Effects of mutation in hepatitis C virus nonstructural protein 5A on interferon resistance mediated by inhibition of PKR kinase activity in mammalian cells

Tohru Noguchi, Shinya Satoh, Takeshi Noshi, Eriko Hatada, Ryuji Fukuda, Akihiko Kawai, Satoru Ikeda, Makoto Hijikata, Kunitada Shimotohno

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

The IFN-induced double-stranded RNA (dsRNA)-activated protein kinase PKR is one of the key molecules in the antiviral effects of IFN. To clarify the effects of hepatitis C virus nonstructural protein 5A (NS5A) on antiviral activity of IFN, in particular on PKR kinase activity, in mammalian cells, we established inducible NS5A-expressing cell lines derived from human osteosarcoma (Saos-2). The cells expressing NS5A derived from an IFN-resistant clone (NS5A-1b) that interacted with endogenous PKR in vitro, showed a suppressive effect on IFN function as determined by interference with vesicular stomatitis virus (VSV) infection, whereas NS5A (NS5A-2a) from an IFN-sensitive clone did not block the antiviral effect of IFN. A mutant with deletion of the IFN sensitivity determining region (ISDR) in NS5A-1b (NS5A-ΔISDR) also interacted with PKR and suppressed its activity in vitro. However, neither NS5A-2a nor the C-terminal truncated mutant of NS5A-1b (NS5A-ΔC) blocked PKR activity. These observations confirmed the previous report that the inhibitory effect of NS5A on IFN activity is mediated at least in part by the repression of PKR. In addition, we showed that IFN sensitivity was determined not only by the ISDR but that the involvement of the C-terminal region of NS5A-1b is important for the suppression of PKR activity.

Original languageEnglish
Pages (from-to)829-840
Number of pages12
JournalMICROBIOLOGY and IMMUNOLOGY
Volume45
Issue number12
DOIs
Publication statusPublished - 2001

Keywords

  • Hepatitis C virus
  • Interferon (IFN)
  • NS5A
  • PKR

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Virology

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