Heat Shock Protein 75 (TRAP1) facilitate the proliferation of the Bombyx mori nucleopolyhedrovirus

The viruses utilize multiple cellular proteins to facilitate their proliferation. The Heat Shock Protein (HSP), the highly conserved protein in eukaryotes and prokaryotes, plays a critical role in facilitating viral proliferation. However, less is known about the role of the HSPs in the life cycles of the Baculoviruses. We constructed recombinant Bombyx mori nucleopolyhedrovirus and discovered the Heat Shock Protein 75 (TRAP1) in the B. mori ovary (BmN) cells by the co-immunoprecipitation experiment using the GP64 (glycoprotein 64) as the bait protein. Tissue expression profile analysis of B. mori indicated that the TRAP1 gene has higher expression levels in the ovary, midgut, and hemolymph. Down-regulation of TRAP1 via RNA interference (RNAi) and geldanamycin (GA, a TRAP1 inhibitor) treatment can reduce the expression level of the major capsid protein VP39 (viral protein 39) of BmNPV. In contrast, the up-regulation of TRAP1 via overexpression can increase the expression level of the VP39. These results indicated that the TRAP1 of B. mori could facilitate the proliferation of the BmNPV. This study provided new insights into the function of TRAP1, and the basic mechanisms of the baculoviruses life cycle for disease prevention.