title: Alteration of large-scale chromatin structure by estrogen receptor.
abstract: The estrogen receptor (ER), a member of the nuclear hormone receptor superfamily important in human physiology and disease, recruits coactivators which modify local chromatin structure. Here we describe effects of ER on large-scale chromatin structure as visualized in live cells. We targeted ER to gene-amplified chromosome arms containing large numbers of lac operator sites either directly, through a lac repressor-ER fusion protein (lac rep-ER), or indirectly, by fusing lac repressor with the ER interaction domain of the coactivator steroid receptor coactivator 1. Significant decondensation of large-scale chromatin structure, comparable to that produced by the approximately 150-fold-stronger viral protein 16 (VP16) transcriptional activator, was produced by ER in the absence of estradiol using both approaches. Addition of estradiol induced a partial reversal of this unfolding by green fluorescent protein-lac rep-ER but not by wild-type ER recruited by a lac repressor-SRC570-780 fusion protein. The chromatin decondensation activity did not require transcriptional activation by ER nor did it require ligand-induced coactivator interactions, and unfolding did not correlate with histone hyperacetylation. Ligand-induced coactivator interactions with helix 12 of ER were necessary for the partial refolding of chromatin in response to estradiol using the lac rep-ER tethering system. This work demonstrates that when tethered or recruited to DNA, ER possesses a novel large-scale chromatin unfolding activity.
authors.affiliation: Department of Cell and Structural Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Nye
authors.forename: Ramji R
authors.initials: RR
authors.lastname: Rajendran
authors.forename: David L
authors.initials: DL
authors.lastname: Stenoien
authors.forename: Michael A
authors.initials: MA
authors.lastname: Mancini
authors.forename: Benita S
authors.initials: BS
authors.lastname: Katzenellenbogen
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Belmont
mesh_terms: D000107:Acetylation; D000818:Animals; D016466:CHO Cells; D018797:Cell Cycle Proteins; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D006224:Cricetinae; D029721:Drosophila Proteins; D004958:Estradiol / Q000378:metabolism; D020847:Estrogen Receptor Modulators / Q000378:metabolism; D047628:Estrogen Receptor alpha; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D051548:Histone Acetyltransferases; D006657:Histones / Q000378:metabolism; D006801:Humans; D007202:Indicators and Reagents / Q000378:metabolism; D007763:Lac Operon / Q000235:genetics*; D008024:Ligands; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D056920:Nuclear Receptor Coactivator 1; D009690:Nucleic Acid Conformation; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D002843:Chromatin; D029721:Drosophila Proteins; D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D006657:Histones; D007202:Indicators and Reagents; D008024:Ligands; D008164:Luminescent Proteins; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C086469:brm protein, Drosophila; D049452:Green Fluorescent Proteins; D004958:Estradiol; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1