Fig. 3.

REV1 and Polζ are essential for tolerance of platinum adducts. HeLa cells were transfected with siRNA and treated with the indicated platinum-containing drugs for 1 h as in Fig. 2A. Cells were fixed 24 h later, fixed, stained for γ-H2AX and DNA content (propidium iodide), and then analyzed by flow cytometry (A and B). Dot plots depicting the level of γ-H2AX staining versus DNA content are shown in A, and the corresponding histograms depicting the DNA content per event are shown in B. Each dot plot is labeled with the percentage of cells displaying enhanced γ-H2AX staining. Each histogram is labeled with the percentage of cells residing in S and G2/M at the time of fixation. Cells can progress through the cell cycle and avoid replication stalling more efficiently in the absence of Polη compared with REV1 and Polζ after treatment with oxaliplatin, satraplatin, or picoplatin. Shown are representative dot plots and histograms from three independent experiments. FITC, fluorescein isothiocyanate.