| Project/Area Number |
17590424
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Virology
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| Research Institution | National Institute of Infectious Diseases |
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Principal Investigator |
FUKUSHI Shuetsu National Institute of Infectious Diseases, Department of Virology 1, Senior Researcher, ウイルス第一部第一室, 主任研究官 (80373398)
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| Co-Investigator(Kenkyū-buntansha) |
MIZUTANI Tetsuya National Institute of Infectious Diseases, Department of Virology 1, Senior Researcher, ウイルス第一部, 主任研究官 (70281681)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | SARS coronavirus / receptor / virus adaptation / mutation / SARS / 感染症 / コロナウイルス |
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| Research Abstract |
The interaction of spike (S) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) and its receptor, ACE2, mediates virus entry into cells. The amino acid mutations within the receptor-binding domain (RBD) of S protein have been suggested to be responsible for adaptation of civet SARS-CoV to human. Rats show lower susceptibility to SARS-CoV infection, since binding affinity of the S protein to rat ACE2 is significantly low. To clarify the molecular basis of virus adaptation to different host species, we have serially passaged SARS-CoV in rat ACE2 expressing CHO cells. After 15th passages of SARS-CoV in rat ACE2 expressing cells, the virus (Rat-P 15) became to replicate effectively in rat ACE2-expressing cells as compared to the parent Frankfurt-1 strain, indicating that Rat-P15 acquired adaptation to rat ACE2-expressing cells. Analysis of nucleotide sequence of the Rat-P 15 S gene revealed two amino acid substitutions in S2 region (A811S and S950F) but none in the RBD. We have employed VSV pseudotype bearing mutant S protein, which mimics infection of SARS-CoV, to analyze the significance of these substitutions. The results showed that two amino acid substitutions in S2 region, especially S950F mutation, were responsible for an efficient infection mediated by rat ACE2. These results suggested that virus adaptation to different host species is dependent not only on amino acid sequences within RBD but also on those within S2 region.
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