Role of homodimerization of human cytomegalovirus DNA polymerase accessory protein UL44 in origin-dependent DNA replication in cells

The presumed processivity subunit of human cytomegalovirus (HCMV) DNA polymerase, UL44, forms homodimers. Dimerization of UL44 is important for binding to DNA in vitro, however whether it is also important for DNA replication in a cellular context is unknown. Here we show that UL44 point mutants that are impaired for dimerization, but not for nuclear localization or interaction with the C-terminus of the polymerase catalytic subunit, are not capable of supporting HCMV oriLyt-dependent DNA replication in cells. These data suggest that disruption of UL44 homodimers could represent a novel anti-HCMV strategy.