Negative regulation of intracellular hepatitis C virus replication by interferon regulatory factor 3
Interferon regulatory factor (IRF)-3 plays an important role in initiating cellular interferon-stimulated gene-mediated antiviral responses. In the present study, we evaluated the effects of IRF-3 expression and activation on intracellular hepatitis C virus (HCV) replication using an HCV replicon system.
An HCV replicon was constructed that expressed a neomycin-selectable chimeric firefly luciferase reporter protein. A small interfering (si) RNA oligonucleotide directed against IRF-3 mRNA was designed and synthesized. A eukaryote expression plasmid vector was constructed that expressed IRF-3 mRNA under control of the cytomegalovirus early promoter/enhancer. To evaluate transcriptional activity of the interferon-stimulated genes, a reporter vector was used that expressed firefly luciferase under control of the interferon-stimulated response element (ISRE).
The baseline expression of IRF-3 did not significantly differ between cells with and without expression of the replicon. Transfection of an IRF-3 expression plasmid into the cells raised the ISRE-luciferase activities. The increase of ISRE activity was significantly more potent in the replicon-expressing cells than in cells without replicon expression. Concomitantly, the overexpression of IRF-3 suppressed HCV replication levels. In contrast, siRNA knockdown of IRF-3 suppressed ISRE activity by 38% ± 2%. Interestingly, the suppression of IRF-3 resulted in a significant increase of HCV replication, by up to twofold, depending on the IRF-3 suppression levels.
IRF-3 negatively regulated intracellular HCV replication, and was partially activated in cells that expressed the HCV replicon. Thus, IRF-3 is a key molecule controlling HCV replication through modulation of host interferon gene responses.
- Negative regulation of intracellular hepatitis C virus replication by interferon regulatory factor 3
Journal of Gastroenterology
Volume 41, Issue 8 , pp 750-757
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- hepatitis C virus
- interferon regulatory factor 3
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- Tsuyoshi Yamashiro (A1) (A3)
- Naoya Sakamoto (A1)
- Masayuki Kurosaki (A1)
- Nobuhiko Kanazawa (A1)
- Yoko Tanabe (A1)
- Mina Nakagawa (A1)
- Cheng-Hsin Chen (A1)
- Yasuhiro Itsui (A1)
- Tomoyuki Koyama (A1)
- Yoshie Takeda (A1)
- Shinya Maekawa (A1) (A2)
- Nobuyuki Enomoto (A2)
- Hiroshi Sakugawa (A3)
- Mamoru Watanabe (A1)
- Author Affiliations
- A1. Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
- A3. First Department of Internal Medicine, School of Medicine, University of the Ryukyus, Okinawa, Japan
- A2. First Department of Internal Medicine, University of Yamanashi, Chuo, Japan