UNRAVELING THE DYNAMICS OF NUCLEAR SPECKLES AND GENE EXPRESSION DURING HERPES VIRUS INFECTION

Nuclear architecture undergoes dramatic changes during lytic viral infection, including changes in the distribution of chromatin and nuclear bodies, such as nuclear speckles that contain many types of splicing factors. DNA viruses induce development of nuclear Viral Replication Compartments (VRCs) which is accompanied by marginalization of host chromatin. Herpes Simplex Virus Type 1 (HSV-1) infection leads to the redistribution of nuclear speckles from the nuclear center to the nuclear periphery, and adjacent to VRCs. In this study we aimed to explore nuclear speckle function and dynamics with respect to viral and cellular RNAs during lytic infection of HSV-1. We observed that different splicing factors, which are nuclear speckle components, were redistributed under viral infection. Interestingly, transcription sites of viral RNA co-localized with nuclear speckles. Moreover, upregulated host gene transcription sites and single transcripts of this gene were associated with nuclear speckles. Taken together, the findings suggest that nuclear speckles play an important role in the regulation of cellular and viral gene expression during infection and might aid in splicing and export of viral and host mRNAs.