Figure 1.

XRCC4–XLF DNA binding. (A) XRCC4 wild-type (WT) and mutants (8 µM) were incubated with 100 ng of DNA with or without 2 µM XLF (WT and mutants), analyzed by EMSA. (B) WT XLF and its mutants (2 µM) were incubated with 100 ng of DNA with or without 8 µM XRCC4 (WT and mutants). (C) Effect of DNA Ligase IV tandem BRCT domains on XRCC4–XLF–DNA complex formation. XRCC4 (8 µM) and XLF (2 µM) were incubated with 100 ng DNA fragments in the presence of increasing amounts of DNA Ligase IV tandem BRCT domains (BRCTs, 0, 0.5, 1, 2, 4–8 µM).