FIGURE 6.
TopBP1 and CRS compete each other for C-tail. A, anti-FLAG beads were pre-bound with 10 pmol of purified FLAG-tagged 9ΔC-1-1 and incubated with GST-tagged C-tail with or without CK2 phosphorylation (P-C-tail or C-tail) at 4 °C for 1 h. After washing the beads, 0, 3, or 5 pmol (−, +, or ++, respectively) of purified TopBP1 were added and further incubated for 1 h at 4 °C. One percent of the input fractions and 30% of the bound fractions were analyzed by immunoblotting using indicated antibodies. B, band intensities of C-tail in the bound fractions were divided by that of Rad9ΔC and the values relative to TopBP1 minus experiments as 100% were plotted as means ± S.E. for four independent experiments.