Considering the difficulties in expressing a UL44 mutant completely impaired in sumoylation, whose activities could be compared to that of wild-type UL44, to gain some insight on the functional role of UL44 sumoylation in the context of HCMV replication we sought to undertake a different approach. We overexpressed SUMO-1 in virus-infected cells and analyzed the effects on the intracellular distribution of UL44, as the targeting to specific subcellular domains is one of most common biological effect exerted by the conjugation of SUMO to a substrate protein.