Fig. 1.

RSF1 preferentially associates with H2Aub-enriched nucleosomes in HeLa cells expressing HA-ubiquitin. (A) Silver staining of a protein gel containing equal amounts of H2Aub-enriched or -depleted mononucleosomes reveals polypeptides enriched specifically within each group of nucleosomes (arrowheads). Different staining times were used for core histones and the rest of the proteins. (B) Anti-HA immunoblot of a protein gel containing an aliquot of the above samples shows that a single protein corresponding to the H2Aub position containing HA-ubiquitin (arrowhead). (C) RSF1 is enriched in the H2Aub-enriched nucleosomes in the SILAC assays, shown by log₂-fold enrichment of RSF1 abundance, quantified by the intensity of a RSF1 unique peptide (Fig. S1), in H2Aub-enriched (+ub) or -depleted (−ub) nucleosomes. H and L represent heavy and light lysine labeling, respectively. (D) Immunoblot analyses of proteins contained in the flow-through (Ft) or the eluate (E) of anti-HA IP of H2Aub-containing nucleosomes show that RSF1 is enriched in the H2Aub nucleosomes, along with SNF2H, another component of the RSF complex. In, input. Antibodies used are indicated at the left.