| The Baculovirus late expression factors (LEFs) are protein factors that regulate late geneexpression, the genes which encoding these proteins are called lefs. Some of them are essential forvirus DNA replication, others are necessary for gene transcription. All of them are necessary forregulation of late gene expression.Targeted gene knockout is recognized as an accurate, effective means to study the genefunction in baculovirus genome, particularly regarding its requirements for DNA replication orgene transcription regulation in the context of the infection cycle. LEF-10of BmNPV possesses nosignificant homology to other genes and maybe a co-factor in the transcription process. However,the effect of LEF-10on virus replication and propagation are still unclear. In this study, wegenerated a lef-10knockout Bacmid by Red recombination in Escherichia coli. Additionally, alef-10-repair Bacmid was constructed by inserting the ORF and promoter element of lef-10into thepolh locus by Bac-to-Bac system. After transfecting the DNA of lef-10knockout Bacmid intoBmN cells, the knockout Bacmid was unable to produce viral progeny, but the virus infection levelof repair Bacmid is recovered similar to wild-type virus. In order to further explore the mechanismof LEF-10, we examined the level of virus DNA replication. Furthermore, the transcription andexpression level of baculovirus early gene, late gene and very late gene in the absence of lef-10were also examined. Our results showed that the viral genome replication levels remained lowafter the loss of lef-10. Moreover, the transcription levels of early gene lef-3, late gene vp39andvery late gene p10were much lower than wild-type virus and lef-10-repair Bacmid; Thetranslation level of early gene lef-3was lower than wild-type virus and lef-10-repair Bacmid.Inconclusion, BmNPV lef-10is essential for virus DNA replication and it has an important influenceon the virus gene transcription and early gene expression. |
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