Summary of the roles of SEs and changes in enhancer regulatory network during BmNPV infection. SEs were clusters of enhancers with high chromatin accessibility and densely enriched interacting factors. In BmN cells, SEs are associated with vital genes in cell state maintenance and ensure robust activation of them. Specifically repressing the regulatory activity results in reduced expression of these vital genes and therefore leads to cell death and apoptosis. In uninfected cells, enhancers play a significant role in the activation of genes related to nucleosome assembly and BmNPV resistance. At the very late stage of BmNPV infection, accessible regions and H3K27ac distribution become staggered, causing reduced activation potential of the intrinsic enhancer regions. Additionally, viral infection radically attenuates chromatin interaction, and these two changes jointly disturb the original enhancer regulatory network, leading to inadequate expression of antiviral genes and nucleosome assembly factors. Such deregulation facilitates viral infection and may account for the increased accessibility mediated by BmNPV. This schematic is modeled on our data, and dotted lines indicate the possible underlying mechanisms based on extrapolation of data. The summary graph was generated using Adobe Illustrator CC 2018.
