Figure 8

Following the removal of 2 mM thymidine from the post-treatment, cells are able to resume cell division at rates comparable to no treatment samples. Following a 24 hour 1 mM pre-treatment with thymidine, cells were collected and stained with the cell-membrane dye, PKH26, and then released into medium supplemented with 2 mM thymidine (iv and v) or complete medium (ii and iii). Fluorescence of the PKH26 dye was measured in a subset of the cells immediately following staining and prior to re-plating to obtain an initial fluorescence value (i: T0); subsequent samples were removed at 48 (ii and iv) and 144 hours (iii and v) following re-plating for the same analysis. Sample (v) was washed 2× with PBS at 48 hours, received fresh medium and analyzed at 144 hours. Values indicate the mean fluorescence intensity (m.f.i.) of the population at each time point (shaded peak); non-shaded graph represents the fluorescence levels at T0 and filled in graphs represent the fluorescence intensity at the indicated times. M1 is the boundary for the PKH26(-) samples and M2 indicates PKH26(+) fluorescence.