| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2005: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2004: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
To investigate the function(s) of the 2b protein of Cucumber mosaic virus (CMV) in the viral pathogenesis, we have made various mutant forms of the 2b gene and analyzed their virulence by expressing using Potato virus X vector or the 2b-deleted RNA2 of CMV. Mutations in the putative phosphorylation site (seine at a position of 40) and its neighboring positions have strong effects on the virulence of the 2b protein. Especially, the amino acid position at 39 affected the virulence of 2b. When the amino acid at the position was changed from lysine to glutaxnic acid, bacic amino acid to acidic amino acid, the virulence of the 2b protein was greatly reduced. By co-agroinfiltration of the green fluorescent protein gene with the mutated 2b protein genes into the leaves of Nicotiana benthamiana, we have analyzed RNA silencing suppression ability of the mutated 2b protein. In these experiments, the mutation of 39K to 39E greatly reduced RNA silencing suppressor capability of the 2b protein. Taken together, it seems probable that the virulence of the 2b protein coincide with the RNA silencing suppressor capability of the 2b protein of CMV. Further studies will be required to figure out the relationship among virulence, RNA silencing suppressor ability and nuclear-cytoplasm shuttle of the 2b protein of CMV ; however, this research provided some steps toward the complete understandings of the function(s) of the 2b protein of CMV pathogenesis.
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