Viruses, by their very nature, are evolved to hijack cellular processes to their own advantage. This essential feature, which can make them to troublesome as a pathogen, also has the potential to reveal new insight into the underlying biology that the virus exploits. In the case of Herpes Simplex Virus type 1 (HSV1), lytic infection causes dramatic changes inside the nucleus of the host cell. As the virus replicates, many nuclear factors are recruited to the sites of viral DNA replication, also known as Replication Compartments. Many components of the general transcriptional machinery, particularly RNA Polymerase II (Pol II) itself, are highly enriched in these replication compartments.
HSV1— a double-stranded DNA virus— depends in Pol II-mediated transcription for the expression of its own genes, and hence such a dramatic shift in the spatial arrangement of the nuclear proteome piqued our interest as an example of the spatial regulation of nuclear processes. Our goal is to utilize the power of quantitative microscopy to understand this process. Using a combination of approaches such as single particle tracking, FRAP, PALM and smFISH, we have uncovered new and interesting principles that govern recruitment to viral Replication Compartments, and have further gained insight into how these mechanisms might also affect uninfected cells.
3D super-resolution PALM image of Pol II relocalization to Replication Compartments after four hours of infection