Repeated baculovirus infections in cultured insect cells lead to the generation of defective interfering viruses (DIs), which accumulate at the expense of the intact helper virus and compromise heterologous protein expression. In particular, Autographa californica multicapsid nucleopolyhedovirus (AcMNPV) DIs are enriched in an origin of viral DNA replication (ori) not associated with the homolo...

UNLABELLED Autographa californica multiple nucleopolyhedrovirus orf132 (named ac132) has homologs in all genome-sequenced group I nucleopolyhedroviruses. Its role in the viral replication cycle is unknown. In this study, ac132 was shown to express a protein of around 28 kDa, which was determined to be associated with the nucleocapsids of both occlusion-derived virus and budded virus. Confocal m...

Baculovirus expression systems for recombinant proteins have found widespread use because they produce biologically active proteins more reliably than do bacterial or yeast expression systems, and the yields generally exceed those from mammalian expression systems. However, optimization of baculovirus yields remains an important issue, especially when biophysical studies are contemplated. Recen...

A new baculovirus-silkworm multigene expression system named Bombyx mori MultiBac is developed and described here, by which multiple expression cassettes can be introduced into the Bombyx mori nuclear polyhedrosis virus (BmNPV) genome efficiently. The system consists of three donor vectors (pCTdual, pRADM and pUCDMIG) and an invasive diaminopimelate (DAP) auxotrophic recipient E. coli containin...

Seven sets of recombinant expression vectors were constructed for the expression of the human anti-bovine serum albumin (BSA) single-chain Fv fragment (scFv) 13CG2 fused to the C terminus of GFP(uv) or bombyxin (bx) signal peptide in the hemolymph and fat body of silkworm larvae and pupae, using cysteine protease- (BmNPV-CP(-)), and cysteine protease- and chitinase-deficient (BmNPV-CP(-)Chi(-))...

Infection of cultured insect cells with Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV) resulted in the generation of mutants with major genomic deletions. Some of the mutants lacked the ability to infect S. exigua larvae per os. The gene(s) responsible for this phenotype in SeMNPV was mapped within a contiguous sequence encoding ORFs 29-35. In this paper we have shown that SeMNPV O...

A recombinant virus lacking the sf32 gene (Sf32null), unique to the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), was generated by homologous recombination from a bacmid comprising the complete viral genome (Sfbac). Transcriptional analysis revealed that sf32 is an early gene. Occlusion bodies (OBs) of Sf32null contained 62% more genomic DNA than viruses containing the sf32 gene...