Comparative proteomic analysis of hemolymph proteins from Autographa californica multiple nucleopolyhedrovirus (AcMNPV)-sensitive or -resistant silkworm strains during infections.

We reported previously that baculovirus AcMNPV host-ranges in silkworm strains are controlled by a novel third chromosomal locus. To further isolate the potential host factor and uncover the functional pathway involved, in this study we analyzed hemolymph proteins from AcMNPV-resistant or -sensitive silkworm strains infected with baculoviruses. All the protein spots from 2D electrophoresis were characterized by MALDI-TOF MS and further systematically assessed for differentially regulated proteins at different stages of infection. Subsequently, six candidates were selected for functional analysis using Bm5 cells, where the candidates were knocked-down or overexpressed. We observed that mRNA expression levels of beta-N-acetylglucosaminidase and prophenoloxidase subunit 2 are significantly upregulated during AcMNPV infections in Bm5 cells. Ultimately, we found that RNA interference of ribosomal protein RpL34 causes serious damages to cell viability as well as abortive infection, indicating that ribosomal components are essential for productive baculovirus infection.