Fig. 5

Localization of HBx and HBV episomes in the context of 3D nuclear topology. The graphic illustrates a model for the implementation of activity-associated nuclear HBV localization into current concepts of nuclear higher-order organization. HBx is associated with the HBV episome via C-terminal binding and this complex translocates to sites of active gene expression, which were previously proposed to be organized as focal ‘transcription factories’—functional assemblies of factors and templates involved in transcription—residing in the interchromatin compartment. Actively transcribed chromatin extrudes from the surface of supranucleosomal chromatin structures (domain units) into an adjacent perichromatin compartment to come in contact with transcription factories and other processing machineries [18,19,20, 24]