FIG 1.

Visualization of newly labeled nuclear and cytoplasmic DNA by confocal microscopy. (A) Approximately 80% confluent A549 cells were infected with VACV at a multiplicity of infection of 10 PFU per cell. Uninfected (un) cells and infected cells at the indicated times were incubated for 1 h with 10 μM EdU and then fixed, permeabilized, and reacted with Alexa Fluor 488 azide. The I3 single-strand binding protein was visualized by staining with a MAb, followed by an anti-mouse secondary antibody conjugated to Alexa Fluor 594. DAPI was used to stain total DNA. The cells were viewed with a confocal microscope, and maximum projections are shown. Each subpanel is divided into quadrants: upper left, DAPI (blue); upper right, EdU (green); lower left, I3 (red); and lower right, merge. (B) Cells were infected for 3.5 h and incubated for 10, 20, or 30 min with EdU as for panel A.