GK2 and infection: To investigate whether GK1 and GK2 affect HCMV gene expression, we mock-infected or infected cells with 53-F [16], a virus that expresses FLAG-tagged UL53 (FLAG-UL53) and GFP, but is otherwise wild type (WT), at a multiplicity of infection (MOI) of 1 in the presence of 10 μM GK1, a dose that reduces plaque formation by ≥5-fold (Fig 3).