FIG. 3.
Rad50-deficient cells do not exhibit telomere defects. (A) Telomere FISH-stained metaphase spreads were analyzed for the presence of fused chromosomes. Fusions with and without telomere sequence at junctions were tabulated. An example of a fusion lacking telomere sequence is shown from a Rad50Δ/− spread. (B) Spontaneous and IR-induced 53BP1 foci in Rad50 control (white bars), Rad50-deficient (gray bars), and Trf2-deficient (black bars) cells were analyzed for colocalization with telomeres. Values represent percentages of 53BP1 foci exhibiting TIFs (*, IR-treated Trf2 deficient cells were not analyzed). Examples of 53BP1 (red)- and TelC (green)-stained cells from Rad50-deficient (C and D) and Trf2-deficient (E and F) cultures.