Figure 2. ATR signaling prevents the SCFSkp2-mediated degradation of MLL.
a, 293T cells were transfected with the FLAG-MLL expressing construct for 2 days, treated with 1 mM HU for the indicated times, and then subjected to anti-FLAG co-immunoprecipitation assays. Immunoprecipitated FLAG-MLL and co-immunoprecipitated Skp2 were determined by anti-FLAG and anti-Skp2 immunoblots, respectively. b, 293T cells synchronized at mid-S phase were treated with HU in the presence of LY294002 (50 µM) or Wortmannin (10 µM) and then subjected to anti-MLLC180 immunoblots. c, Genetic deletion of ATR prevented the DNA damage-induced accumulation of MLL. MEFs were treated with γ-IR (5 Gy) or HU and then subjected to anti-MLL immunoblots.