Mechanism of cell fusion induced by the expression of Sendai virus membrane protein genes.
| Project/Area Number |
07660088
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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 |
応用微生物学・応用生物化学
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| Research Institution | IWATE UNIVERSITY |
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Principal Investigator |
TAIRA Hideharu Iwate University, Fac.Agric., Professor, 農学部, 教授 (70045756)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Sendai virus / fusion protein / hemagglutinin-neuraminidase protein / cell fusion / gene expression |
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| Research Abstract |
Sendai virus contains two glycoproteins, fusion (F) and hemagglutinin-neuraminidase (HN) proteins. The F protein, which is proteolytically processed to F1 and F2, is absolutely required for fusion, but the role of the HN protein is less clear. The structure and the function of the F and HN proteins was examined by using site-directed mutagenesis and expression of the mutant proteins.
(1) In contrast to the wild type F protein, a mutant F,having a cleavage motif similar to that of virulent Newcastle disease virus F,could be cleaved by proteases present in COS cells. When mutant F and wild HN were coexpressed at the cell surface, syncytium formation was observed.
(2) The role of intramolecular disulfide bond in the F protein was examined. The two cysteine residues at position 70 of the F2 subunit and 199 of F1 subunit were changed to serine residues. Intracellular transport of the cysteine mutant F proteins to the cell surface was reduced and defective in cleavage. These results suggest that the disulfide bond is crucial to the correct folding of the F proteins.
(3) For the F protein, elimination of N-glycosylation in site 1 exhibited a great increase in fusion activity with HN protein, but elimination in other site leaded to a misfolded, aggregated molecule. For HN protein, elimination of N-glycosylation in sites of globular domain blocked transport out of the ER.
(4) The role of leucine zipper motif in transmembrane domain of HN protein was examined. The mutant HN protein containing all three leucine, isoleucine-to-alanine substitutions exhibited a decrease in fusion promoting activity.
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Report
(3 results)
Research Products
(12 results)
