Protein composition of the occlusion derived virus of Chrysodeixis chalcites nucleopolyhedrovirus.

Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV) is a group II NPV and its genome has 151 predicted open reading frames. In this study, the protein composition of ChchNPV occlusion derived virus (ODV) was determined by LC-MS/MS. Fifty-three proteins were identified in ChchNPV ODV particles. One ODV-protein is encoded by a gene so far unique to ChchNPV (Chch105). The two DNA photolyases PHR1 and PHR2, which are characteristic for ChchNPV and thought to be involved in repairing UV damage in viral DNA, were not detected in the ODVs. Comparison of the ODV proteins identified in ChchNPV and in three other baculoviruses enabled the identification of ten conserved ODV proteins (ODV-E18, ODV-E56, ODV-EC27, ODV-EC43, P6.9, P33, P49, P74, GP41, and VP39). In addition, the baculovirus per os infectivity factors PIF1, PIF2 and PIF3 were all detected in ChchNPV and these should be considered as conserved ODV proteins as well as they are absolutely required for oral infection. With the LC-MS/MS method used 22 viral proteins were detected, which were not identified as ODV proteins in previous studies.