FIG. 7.

Determination of BrdU incorporation in synchronized cells exposed to E22ΔEspB or E22. HeLa cells were synchronized at the G₁/S border and exposed for 4 h to bacteria at the time of release. Cells were treated for 30 min with BrdU (5 μg/ml) 5 or 24 h after release. Incorporated BrdU was labeled by FITC indirect immunofluorescence, and DNA was labeled by propidium iodide. Contour maps of DNA versus BrdU contents are on the upper row, and corresponding DNA frequency distributions are displayed below.