FIG. 1.

Human Ku86-deficient cell lines have shortened telomeres. Genomic DNA was purified from the indicated cell lines, digested to completion with MboI and AluI, and then subjected to terminal restriction fragment Southern blot analysis under denaturing conditions with a (C₃TA₂)₃ 5′-end-radiolabeled oligonucleotide probe. Lanes: 1, HCT116 parental cell line; 2 and 3, HCT116 Ku86-heterozygous cell lines #44 and #70, respectively; 4, HCT116 p53-null cell line; 5 and 6, HCT116 p53-null Ku86-heterozygous cell lines #13 and #20, respectively. Approximate molecular size markers are shown on the far left.