K63RUb phenotype is not due to NHEJ.

<p>(A-C) Clonogenic survival of WT and K63R Ub cells after treatment with (A) 1 µM DNA-PKi alone for indicated times, (B) 1 µM DNA-PKi for 24 or 48 hrs, started 1 h before combined 24 hrs treatment with 50 nM CPT or (C) 1 µM DNA-PKi for 24 hrs, started 1 h before 2 Gy IR (A-C) mean ± s.d. (n = 3). (D) Mutations at the <i>HPRT</i> locus were determined after continuous treatment with 1 µM DNA-PKi started 1 h before combined with additional treatments either spontaneous or 20 nM CPT for 6 days total, mean ± s.d. (n = 5).