An Ikaros-Containing Chromatin-Remodeling Complex in Adult-Type Erythroid Cells

作者：David W. O’Neill, Stuti Schoetz, Rocío López, Madalyn Castle, Lisa Rabinowitz, Erika Shor, Dayana Krawchuk, Mary Grace Goll, Manfred Renz, Hans-Peter Seelig, Sunmi Han, Rho Hyun Seong, Sang D. Park, Theodora Agalioti, Nikhil Vilas Munshi, Dimitrios Thanos, Hediye Erdjument‐Bromage, Paul Tempst, Arthur Bank · 发表于：Molecular and Cellular Biology · 年份：2000 · DOI：10.1128/mcb.20.20.7572-7582.2000 · 被引用次数：165 · 研究领域：Acute Lymphoblastic Leukemia research、Hemoglobinopathies and Related Disorders、Chromatin Remodeling and Cancer

We have previously described a SWI/SNF-related protein complex (PYR complex) that is restricted to definitive (adult-type) hematopoietic cells and that specifically binds DNA sequences containing long stretches of pyrimidines. Deletion of an intergenic DNA-binding site for this complex from a human beta-globin locus construct results in delayed human gamma- to beta-globin switching in transgenic mice, suggesting that the PYR complex acts to facilitate the switch. We now show that PYR complex DNA-binding activity also copurifies with subunits of a second type of chromatin-remodeling complex, nucleosome-remodeling deacetylase (NuRD), that has been shown to have both nucleosome-remodeling and histone deacetylase activities. Gel supershift assays using antibodies to the ATPase-helicase subunit of the NuRD complex, Mi-2 (CHD4), confirm that Mi-2 is a component of the PYR complex. In addition, we show that the hematopoietic cell-restricted zinc finger protein Ikaros copurifies with PYR complex DNA-binding activity and that antibodies to Ikaros also supershift the complex. We also show that NuRD and SWI/SNF components coimmunopurify with each other as well as with Ikaros. Competition gel shift experiments using partially purified PYR complex and recombinant Ikaros protein indicate that Ikaros functions as a DNA-binding subunit of the PYR complex. Our results suggest that Ikaros targets two types of chromatin-remodeling factors-activators (SWI/SNF) and repressors (NuRD)-in a single c...