d ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle.

ORF11 (ac11) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved gene with unknown function. To determine the role of ac11 in the baculovirus life cycle, an ac11 knockout mutant of AcMNPV, Ac11KO, was constructed. Northern blot and 5= rapid amplification of cDNA ends (RACE) analyses revealed that ac11 is an early gene in the life cycle. Microscopy, titration assays, and Western blot analysis revealed that budded viruses (BVs) were not produced in Ac11KO-transfected Sf9 cells. However, quantitative PCR (qPCR) analysis demonstrated that the deletion of ac11 did not affect viral DNA replication. Furthermore, electron microscopy revealed that there was no nucleocapsid in the cytoplasm or plasma membrane of Ac11KO-transfected cells, which demonstrates that the defect in BV production in Ac11KO-transfected cells is due to the inefficient egress of nucleocapsids from the nucleus to the cytoplasm. In addition, electron microscopy observations showed that the nucleocapsids in the nucleus were not enveloped to form occlusion-derived viruses (ODVs) and that their subsequent embedding into occlusion bodies (OBs) was also blocked in Ac11KO-transfected cells, demonstrating that ac11 is required for ODV envelopment. These results therefore demonstrate that ac11 is an early gene that is essential for BV production and ODV envelopment. IMPORTANCEBaculoviruses have been extensively used not only as specific, environmentally benign insecticides but also as helper-independent protein expression vectors. Although the function of baculovirus genes in viral replication has been studied by using gene knockout technology, the functions of more than one-third of viral genes, which include some highly conserved genes, are still unknown. In this study, ac11 was proven to play a crucial role in BV production and ODV envelopment. These results will lead to a better understanding of baculovirus infection cycles. The Baculoviridae are a family of insect-specific doublestranded DNA (dsDNA) viruses. Viruses from this family are characterized by rod-shaped, enveloped nucleocapsids with circular, covalently closed, double-stranded DNA genomes of 80 to 180 kbp (1-3). The Baculoviridae family comprises four genera: Alphabaculovirus, Betabaculovirus, Gammabaculovirus, and Deltabaculovirus. Alphabaculoviruses and betabaculoviruses infect lepidopteran larvae, whereas gammabaculoviruses and deltabaculoviruses infect hymenopteran and dipteran larvae, respectively (4). The alphabaculoviruses are further divided into group I and group II on the basis of phylogenetic analysis (5) and the type of envelope fusion protein (GP64 and F, respectively) (6).The infection cycle of baculoviruses includes two distinct viral phenotypes: budded virus (BV) and occlusion-derived virus (ODV). Both BVs and ODVs are identical in terms of nucleocapsid structure and genetic information, but the composition of their envelopes is different to accommodate their respective functions in the infection cycle (7). ODVs, which become embedded ...

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The Asian honeybee, Apis cerana, is a native honeybee species in Korea which is important in agriculture for pollination and honey production. For better understanding of the physiology of A. cerana, high-throughput Illumina transcriptome sequencing was performed to analyze the gene expression profiles of queen, worker, and larva. A total of 219,799,682 clean reads corresponding to 22.2 Gb of nucleotide sequences was obtained from the whole body total RNA samples. The Apis mellifera reference mRNA sequence database was used to measure the gene expression level with Bowtie2 and eXpress software, and the Illumina short reads were then mapped to 11,459 out of 11,736 A. mellifera reference genes. Total of 9,221 genes with FPKM value greater than 5 of each sample group were subjected to eggNOG with BLASTX for gene ontology analysis. The differential gene expression between queen and worker, and worker and larva were analyzed to screen the overexpressed genes in each sample group. In the queen and worker sample group, total of 1,766 genes were differentially expressed with 887 and 879 genes overexpressed over two folds in queen and worker, respectively. In the worker and larva sample group, total of 1,410 genes were differentially expressed with 1,009 and 401 genes overexpressed over two folds in worker and larva, respectively. IntroductionApis cerana, the Asian honeybee is a native bee species to eastern and southeastern Asian countries such as Korea, China, and Japan. In Korea, A. cerana is one of the most important honeybee species along with western honeybee, Apis mellifera because not only of the economic importance of honey production, but also the importance as one of the pollinator species in agriculture. Also A. cerana had been concerned of its strong resistance to the ectoparasitic mites (Peng et al., 1987).However, the recent outbreak of sacbrood virus (SBV) belonging to the genus Iflavirus which infects A. cerana (Choi et al., 2010) caused a devastating colony loss of Korean honeybee industry.SBV infected larva fails to pupate, and accumulates virus enriched ecdysal fluid beneath its unshed skin (Bailey et al., 1964). SBV also infects adult bees, however, the mortality

A novel recombinant bacmid, bEasyBm, that enables the easy and fast generation of pure recombinant baculovirus without any purification step was constructed. In bEasyBm, attR recombination sites were introduced to facilitate the generation of a recombinant viral genome by in vitro transposition. Moreover, the extracellular RNase gene from Bacillus amyloliquefaciens, barnase, was expressed under the control of the Cotesia plutellae bracovirus early promoter to negatively select against the nonrecombinant background. The bEasyBm bacmid could only replicate in host insect cells when the barnase gene was replaced with the gene of interest by in vitro transposition. When bEasyBm was transposed with pDualBac-EGFP, the resulting recombinant virus, EasyBm-EGFP, showed high levels of EGFP expression efficiency compared with that of non-purified recombinant virus BmGOZA-EGFP, which was constructed using the bBmGOZA system. In addition, nonrecombinant backgrounds were not detected in unpurified EasyBm-EGFP stocks. Based on these results, a high-throughput system for the generation of multiple recombinant viruses at a time was established.