| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
The US2 gene is conserved among alphaherpesvirus subfamily, but its function is not known. In previous report, pseudrabies virus (PRV) US2 proteis known to have a CAAX motif in the N-terminal and its prenylation is required for proper membrane protein association. (Amanda C.C et al J.V 77:1285-12298). HSV-2 Us2 protein also has a predicted prenylation site at N-terminal. To investigate whether HSV-2 US2 is prenylated during infection, Vero cells were infected with HSV-2 with a prenylation inhibitor, Lovasatatin. Infected cells were collected at indicated times and western blotting was performed. Lovastatin did not change the electrophoretic mobility of US2. These data indicated that HSV2 US2protein is an unprenylated protein.
Next, we investigated virus-cell interactions using a US2-deficient HSV (US2Δ) and PC12 cells which respond to NGF by the induction of the neuronal phenotype. Differenciated PC12 cells were infected with US2Δ or its parental wild-type HSV and examined for cellular responses and the localization of viral proteins including UL18 capsid protein and VP16 tegument protein. However, no significant differences were observed between US2Δ and the wild-type virus.
We also studied the role of the US2 gene in viral pathogenicity in mice. BALB/C mice were intranasally inoculated with US2Δ or the wild type. There was little or no difference between the two in the survival curves. In wild-type virus-infected mice, viral antigen was detected in both the olfactory nerve and the olfactory bulb on day 5. In US2Δ-infected mice, however, viral antigen was detectable in the olfactory nerve but not in the olfactory bulb. Similar results were obtained on day 6. The trigeminal ganglia were positive for viral antigen in both cases. These results suggest that there are two neural invasion pathways after intranasal HSV infection ; 1) via olfactory nerve to the CNS, and 2) via trigeminal ganglia to the CNS, and that US2Δ can use only the pathway via olfactory nerve.
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