Murine polyomavirus DNA transitions through spatially distinct nuclear replication subdomains during infection

The replication of small DNA viruses requires both host DNA replication
and repair factors that are often recruited to subnuclear domains termed
viral replication centers (VRCs). Aside from serving as a spatial focus
for viral replication, little is known about these dynamic areas in the
nucleus. We investigated the organization and function of VRCs during
murine polyomavirus (MuPyV) infection using 3D structured illumination
microscopy (3D-SIM). We localized MuPyV replication center components,
such as the viral large T-antigen (LT) and the cellular replication
protein A (RPA), to spatially distinct subdomains within VRCs. We found
that viral DNA (vDNA) trafficked sequentially through these subdomains
post-synthesis, suggesting their distinct functional roles in vDNA
processing. Additionally, we observed disruption of VRC organization and
vDNA trafficking during mutant MuPyV infections or inhibition of DNA
synthesis. These results reveal a dynamic organization of VRC components
that coordinates virus replication.