title: ATP-dependent mobilization of the glucocorticoid receptor during chromatin remodeling.
abstract: Chromatin remodeling by the glucocorticoid receptor (GR) is associated with activation of transcription at the mouse mammary tumor virus (MMTV) promoter. We reconstituted this nucleoprotein transition with chromatin assembled on MMTV DNA. The remodeling event was ATP dependent and required either a nuclear extract from HeLa cells or purified human Swi/Snf. Through the use of a direct interaction assay (magnetic bead pull-down), we demonstrated recruitment of human Swi/Snf to MMTV chromatin by GR. Unexpectedly, we found that GR is actively displaced from the chromatin template during the remodeling process. ATP-dependent GR displacement was reversed by the addition of apyrase and was specific to chromatin templates. The disengagement reaction could also be induced with purified human Swi/Snf. Although GR apparently dissociated during chromatin remodeling by Swi/Snf, it participated in binding of the secondary transcription factor, nuclear factor 1. These results are paralleled by a recent discovery that the hormone-occupied receptor undergoes rapid exchange between chromatin and the nucleoplasmic compartment in living cells. Both the in vitro and in vivo results are consistent with a dynamic model (hit and run) in which GR first binds to chromatin after ligand activation, recruits a remodeling activity, facilitates transcription factor binding, and is simultaneously lost from the template.
authors.affiliation: Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5055, USA.
authors.forename: Terace M
authors.initials: TM
authors.lastname: Fletcher
authors.forename: Nianqing
authors.initials: N
authors.lastname: Xiao
authors.forename: Gisele
authors.initials: G
authors.lastname: Mautino
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Baumann
authors.forename: Ronald
authors.initials: R
authors.lastname: Wolford
authors.forename: Barbour S
authors.initials: BS
authors.lastname: Warren
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Hager
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018189:Immunomagnetic Separation; D046911:Macromolecular Substances; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D011965:Receptors, Glucocorticoid; D000255:Adenosine Triphosphate; D004247:DNA