Fig. 3.

Mitigation of DNA strand breaks and proliferative arrest observed upon MTH1 depletion in p53-null cells correlates with low OGG1 expression.

A. Loss of p53 in A549 cells corresponds to decreased OGG1 levels. Immunoblotted total protein lysates were probed with the indicated antibodies. Tubulin is shown as the loading control. B. Loss of p53 in HCT116 colorectal cells corresponds to decreased OGG1 levels. Isogenic HCT116 cells either wildtype (wt) or null (KO) for p53 were immunoblotted against the indicated antibodies with GAPDH as the loading control. C. HCT116 cells lacking p53 do not express the cell cycle arrest marker, p21^cip1 upon MTH1 depletion. Immunoblotted total protein lysates were probed with the indicated antibodies. GADPH is shown as the loading control. D. Alkaline comet assay. Percentage of cells with no tails (as in Fig. 2E) vs. those with DNA tails (indicating DNA breaks) are graphed for the indicated samples. Note we did not observe the variations in DNA olive tail moments seen for A549 (Fig. 2E) to warrant separation of HCT116 cells into ‘medium’ and ‘long’ tails. Error bars (± SD) and p-values from an unpaired Student t test are shown from two independent experiments.