The Spatial Organization of DNA Virus Genomes in the Nucleus

During lytic infection, DNA viruses that replicate in the nucleusof cells establish an environment that favors viral replication whileevading cellular defenses. Consequently, these viruses must engagewith cellular factors that are necessary for efficient viraltranscription and DNA replication, while disarming restrictivecellular responses to the presence of the invading pathogenicDNA. It is important to consider these events not only at thebiochemical level of protein-protein and protein-nucleic acidinteractions, but also in terms of spatial organization within thenucleus. The nucleus contains many distinct substructures,including nucleoli, chromosome territories, splicing speckles,PML Nuclear Bodies (PML NBs, also known as ND10), andtranscription sites, all of which are in a dynamic environmentinvolving the exchange of protein molecules between thestructures themselves and the general nucleoplasm [1]. DNAviruses establish their own transcription sites and replicationcompartments within the nucleus, and a topic that has been ofinterest for many years is how these virus-specific loci relate to thepreexisting cellular nuclear substructures, particularly during theearly stages of infection. Is viral genome localization random, or isit regulated in some way?Gerd Maul made a breakthrough discovery when he found thatafter their delivery into the nucleus, the genomes of many differentDNA viruses are frequently associated with PML NBs [2,3]. Theseintriguing findings posed many questions: How does thisassociation occur? What are the viral and cellular signals involved?Does the association have a positive or negative influence oninfection?