Autographa califomica M nucleopolyhedrovirus open reading frame 109 affects infectious budded virus production and nucleocapsid envelopment in the nucleus of cells

Autographa californica M nucleopolyhedrovirus (AcMNPV) open reading frame 109 (ac109) is conserved in all known baculovirus genomes, suggesting a crucial role in virus replication. Although viruses lacking ac109 have been previously characterized, the phenotypes differ from production of noninfectious virions to lack of virion production. To re-examine ac109 function, we constructed a recombinant AcMNPV bacmid, AcBAC109KO, with a deletion in ac109. We did not detect infectious budded virus after transfection of AcBAC109K0 DNA into cells. In the nucleus, nucleocapsids had envelopment defects and polyhedra lacked virions. DNA synthesis and gene expression between AcBAC109K0 and a control virus were similar. However, lower levels of non-infectious budded virus were detected from AcBAC109K0 DNA-transfected cells compared to the parental virus using Q-PCR to detect viral DNA or by immunoblotting to detect a budded virus protein. Therefore, deletion of ac109 affects envelopment of nucleocapsids in the nucleus and the production of infectious budded virus. (C) 2012 Elsevier Inc. All rights reserved.