AcMNPV ac143 (odv-e18), a core gene that forms a cluster with ac142, is essential and mediates BV production

CHRISTINA B. MCCARTHY; CAM DONLY; *DAVID A. THEILMANN

Coventry

Congreso; 41st Annual Meeting of the Society for Invertebrate Pathology and 9th International Conference on Bacillus thuringiensis; 2008

Society for Invertebrate Pathology (SIP)

Autographa californica Multiple Nucleopolyhedrovirus (AcMNPV) ac143(odv-e18) is a late gene that encodes for a predicted 9.6 kDa structural protein that locates to the occlusion derived viral envelope and viral induced intranuclear microvesicles (Braunagel et al., 1996. Virology 122:100). To examine the role of ac143 in the baculovirus life cycle, we used the AcMNPV bacmid system to generate an ac143 knockout (KO) virus (AcBACac142REP-ac143KO). Fluorescence and light microscopy showed that infection by AcBACac142REP-ac143KO is limited to a single-cell and titration assays confirmed that AcBACac142REP-ac143KO was unable to produce budded virus (BV). This is a very similar phenotype to the ac142 KO virus. Progression to very late phases of the viral infection was evidenced by the development of occlusion bodies in the nuclei of transfected cells. This correlated with the fact that viral DNA replication was unaffected in AcBACac142REP-ac143KO -transfected cells. This study shows that ac143 is essential, clusters with ac142, and is a baculovirus core gene.