Deletion of MVA ORF 186 encoding the 68k-ank protein prevents viral genome replication. HeLa cells were mock infected or infected with 5 PFU/cell of MVA or MVA-Δ186 (Δ186) and incubated with EdU (10 μM) for 1-h periods at 3, 4, and 5 h after infection. Following each incubation time, the cells were fixed, permeabilized, and reacted with Alexa Fluor 647 azide. The I3 single-stranded DNA binding protein was visualized by staining with a specific MAb, followed by an anti-mouse secondary antibody conjugated to Alexa Fluor 568 and DAPI to stain total DNA. Images were captured with a confocal microscope. Each panel is divided into quadrants: upper left, I3 (red); upper right, EdU (green); lower left, DAPI (blue); and lower right, merge. The scale bar represents 10 μm. hpi, hours postinfection.