Baculovirus Controls Host Catapillars by Manipulating Host Physiology and Behavior

© 2015 TERRAPUB, Tokyo. All rights reserved. doi:10.5047/agbm.2015.00501.0001 (Keddie et al. 1989). At the late stage of infection, a markedly enhanced locomotion behavior of infected larvae is observed (Goulson 1997), which is followed by a dramatic degradation of the host cadaver. The Bombyx mori NPV (BmNPV), one of the wellcharacterized baculoviruses, is a virus specifically pathogenic for the domesticated silkworm B. mori. B. mori has been used for silk production for about 5,000 years. In addition to the large-scale propagation and use in silk production for the textile-industry, B. mori has recently become an important bioreactor for recombinant protein production. In Japan, two essential biotechnological methods have been developed; a system for transposon-based germline transformation in B. mori (Tamura et al. 2000) and a BmNPV-derived foreign gene expression system (Maeda et al. 1985). Maeda et al. (1985) developed a BmNPV expression vector that utilizes the strong promoter for the polyhedrin gene (polh) and reported a mass production of recombinant human α-interferon in silkworm (Maeda et al. 1985). This is the first report of a high level production of a foreign gene product in a living Abstract Nucleopolyhedroviruses (NPVs) belonging to the family Baculoviridae are large, enveloped, double-stranded DNA viruses that are pathogenic to insects. The Bombyx mori NPV (BmNPV) is an NPV pathogenic to the domesticated silkworm B. mori. DNA sequencing revealed that BmNPV potentially encodes 136 putative proteins. Mutagenesis experiments have discovered the viral proteins that control host catapillars at cellular and/or organismal levels: ecdysteroid UDP-glucosyltransferase inactivates an insect molting hormone ecdysone, protein tyrosine phosphatase is involved in wandering behavior at the late stage of infection, fibroblast growth factor induces host cell chemotaxis, and chitinase and cathepsin are required for postmortem host liquefaction. Furthermore, comparative analyses of the genomes of B. mori and baculoviruses have revealed that the modern lepidopteran baculoviruses may have acquired and modified several genes from an ancestral host insect to control the physiology of their own hosts and to increase the efficiency of virus transmission in nature. In this review, I describe our research progress on functional analyses of BmNPV genes that are involved in manipulating host physiology and behavior. Baculovirus Controls Host Catapillars by Manipulating Host Physiology and Behavior