Beads were washed 2× with RIPA buffer (50 mM Tris [pH 8], 150 mM NaCl, 1 mM EDTA, 1% NP-40, 0.1% SDS, 0.5% deoxycholate), 1× with high salt buffer (50 mM Tris [pH 8], 500 mM NaCl, 1 mM EDTA, 1% NP-40, 0.1% SDS), and 1× with TE buffer.