Figure S1. G9a and SUV39h1 strongly associate with mononucleosomes in both HCT116 and 293T cells. Mononucleosomal digests prepared by extensive MNase digestion of nuclei from (A) HCT116 cells and (B) 293T cells were resolved by ultracentrifugation on a sucrose density gradient (5% to 25%) containing 300 mM NaCl. Gradients were fractionated and analyzed as described previously. The control lanes (denoted as C) on the gels were loaded with unfractionated nuclear extract loaded on the gels to monitor the quality of the immunostaining of the membranes.