| Research Abstract |
In this study, we focused our efforts mostly to following points.
1. In order to elucidate possible role(s) of VAP21 in the viral replicative process, we examined whether the VAP21 is incorporated into the mature virions of other enveloped viruses, including VSV, Sindbis virus and herpes simplex virus-1. The studies resulted in demonstrating the incorporation of VAP21 into the virions of these viruses, in which the interaction of VAP21 with certain viral protein of each virus was suggested to be involved.
2. Secondly, we investigated possible relationships between the content of VAP21 in the cell and the yield of VSV replication. For this purpose, we compared three hamster cell lines (i.e., BHK-21, HmLu and CHO-KI cells), which demonstrated different amounts of VAP21 in each cell line, and apparently rough correlation between the amounts of intracellular VAP21 and VSV yields. CHO-Ki cells contained little VAP21 and produced much less amounts of the virus, while the cells produced similar amounts of viral proteins and RNA which corresponded to those produced in BHK-21 cells capable of producing maximum levels of virus production. We also tried to reduce the amount of VAP21 in BHK-21 cells by introducing the VAP21 cDNA in opposite direction, by which the cells produce the anti- sense mRNA.The data obtained so far suggest that reduction of VAP21 production also resulted in reducing the progeny virus yields, although not so greatly.
3. Amino acid substitution at alanine-72 of VAP21 with methionine allowed us to investigate the possible mechanism of VAP21 synthesis. Using this mutant, we could confirm the presumed cleavage process of the signal peptide from the VAP21 precursor.
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