| 研究実績の概要 |
Influenza A virus (IAV) matrix protein 2 (M2) is an integral membrane, ion channel protein. IAVs express three viral envelop proteins in infected cells i.e. hemagglutinin (HA) and neuraminidase (NA) & M2. Though all three viral envelop proteins are abundantly expressed in infected cells, only HA and NA become the major viral envelop proteins. Both HA and NA are targeted to the lipid rafts, whereas M2 is excluded from lipid rafts. The transmembrane domains (TMDs) of M2, HA and NA are 19, 27 and 29 residues long. Despite the presence of two host-cell membrane lipid-raft targeting features i.e., palmitoylation at Cys50 and cholesterol recognition/interaction amino acid consensus (CRAC) motif, relatively shorter M2-TMD is believed to prevent its association with lipid-raft domains. Therefore, we investigated the mechanism of interaction/incorporation of M2-TMD in non-raft regions of host cell membrane.
So far, we have generated M2-TMD mutants by inserting 3, 6 and 8 amino acid (aa) residues in N-terminal end of TMD. We also introduced similar mutations in M gene for generating viruses by reverse genetics. Then, we characterized the M2-TMD mutants by comparing the cell surface expression, cytotoxic potential and lipid raft association of tested M2 mutants with that of wtM2 protein. It was found that M2 mutants , like wtM2, were expressed on cell surface and displayed cytotoxic potential. Interestingly, it was found that increasing the TMD length did not affect their non-lipid raft association character, and like wtM2, M2-TMD mutants remained in the non-raft microdomains.
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| 今後の研究の推進方策 |
1. To examine the effect of increase in the length of M2 transmembrane domain by insertion mutations on virus release by techniques such as real-time PCR, electron microscopy, etc.
2. To examine the effectof increase in the length of M2 transmembrane domain by insertion mutations on virus replication kinetics.
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