Baculovirus-mediated immediate-early gene expression and nuclear reorganization in human cells.

Baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), has the ability to transduce mammalian cell lines without replication. The general objective of this study was to detect the transcription and expression of viral immediate-early genes in human cells and to examine the interactions between viral components and subnuclear structures. Viral capsids were seen in large, discrete foci in nuclei of both dividing and non-dividing human cells. Concurrently, the transcription of viral immediate-early transregulator genes (ie-1, ie-2) and translation of IE-2 protein were detected. Quantitative microscopy imaging and analysis showed that virus transduction altered the size of promyelocytic leukaemia nuclear bodies, which are suggested to be involved in replication and transcription of various viruses. Furthermore, altered distribution of the chromatin marker Draq5 and histone core protein (H2B) in transduced cells indicated that the virus was able to induce remodelling of the host cell chromatin. To conclude, this study shows that the non-replicative insect virus, baculovirus and its proteins can induce multiple changes in the cellular machinery of human cells.