The human cytomegalovirus (HCMV) DNA polymerase includes a catalytic subunit, UL54 (the UL54 gene product), and an accessory, homodimeric subunit, UL44 (the UL44 gene product), that binds DNA without the aid of clamp loaders [7] yet wraps around DNA akin to PCNA [8] . While UL44 shows no apparent sequence homology with PCNA, there is striking structural similarity between UL44 and PCNA monomers [2, 9] . Similarly to PCNA, UL44 is a phosphoprotein [10] . Intriguingly, the phosphorylation state of UL44 has been shown to regulate its nuclear import rate by controlling its interaction with host cell factors [11, 12, 13] . The best-characterized function of UL44 during HCMV infection is that of binding to UL54 through a region named connector loop [14, 15, 16] , stimulating its activity and conferring processivity to the holoenzyme [17, 18] . However, UL44 continues to accumulate to strikingly high levels at late times after infection, when DNA replication is accomplished [19, 20] . Its early-late kinetics of transcription and the high level of expression suggest that UL44 might play additional roles during the viral life cycle.