Objective: The occlusion-derived form of baculovirus is specially adapted for primary infection of host midgut epithelial cells. The virion contains proteins essential for host-range determination and initiation of infection. Determination of protein composition of the occlusion-derived virus (ODV) will help us to understand this virion's infection mechanism.
Methods: We obtained the ODV virion of Bombyx mori nucleopolyhedrovirus (BmNPV) by sucrose density gradient centrifugation, and used SDS-PAGE, 2-dimensional electrophoresis and mass spectrometry to identify--for the first time--proteins present within or associated with the ODV virion.
Results: 20 proteins, including 16 major proteins of the virion encoded by BmNPV and 4 proteins of the silkworm, were identified with confidence.
Conclusion: Three BmNPV proteins (orf40, P95 and protein tyrosine phosphatase), which had not been detected as components of ODV previously, were identified in this study. We propose that the host-derived proteins may be important for the assembly and maturation of the ODV capsid.
2009 S. Karger AG, Basel.