An Ikaros-containing chromatin-remodeling complex in adult-type erythroid cells Journal Article

Authors: O'Neill, D. W.; Schoetz, S. S.; Lopez, R. A.; Castle, M.; Rabinowitz, L.; Shor, E.; Krawchuk, D.; Goll, M. G.; Renz, M.; Seelig, H. P.; Han, S.; Seong, R. H.; Park, S. D.; Agalioti, T.; Munshi, N.; Thanos, D.; Erdjument-Bromage, H.; Tempst, P.; Bank, A.
Article Title: An Ikaros-containing chromatin-remodeling complex in adult-type erythroid cells
Abstract: 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 complex (PYR complex) to the beta-globin locus in adult erythroid cells. At the time of the switch from fetal to adult globin production, the PYR complex is assembled and may function to repress gamma-globin gene expression and facilitate gamma- to beta-globin switching.
Keywords: dna-binding proteins; gene; globin gene; in-vitro; histone deacetylase; messenger-rnas; nucleosome disruption; sequence databases; transcription factor-binding; yeast swi/snf complex; terminal transferase
Journal Title: Molecular and Cellular Biology
Volume: 20
Issue: 20
ISSN: 0270-7306
Publisher: American Society for Microbiology  
Date Published: 2000-10-01
Start Page: 7572
End Page: 7582
Language: English
ACCESSION: WOS:000089504500015
DOI: 10.1128/mcb.20.20.7572-7582.2000
PUBMED: 11003653
Notes: Article -- Source: Wos
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MSK Authors
  1. Paul J Tempst
    323 Tempst