Plays an essential role in viral DNA replication by acting as the polymerase accessory subunit. Associates with the viral polymerase to increase its processivity and forms high-affinity direct interactions with DNA. Facilitates the origin-binding protein UL9 loading onto DNA thus increasing its ability to assemble into a functional complex capable of unwinding duplex DNA (By similarity). Interacts with the DNA polymerase catalytic subunit. Interacts with the origin-binding protein (By similarity). Belongs to the herpesviridae DNA polymerase processivity factor family.