Structure and dynamic properties of a glucocorticoid receptor-induced chromatin transition.
Activation of the mouse mammary tumor virus (MMTV) promoter by the glucocorticoid receptor (GR) is associated with a chromatin structural transition in the B nucleosome region of the viral long terminal repeat (LTR). Recent evidence indicates that this transition extends upstream of the B nucleosome, encompassing a region larger than a single nucleosome (G. Fragoso, W. D. Pennie, S. John, and G. L. Hager, Mol. Cell. Biol. 18:3633-3644). We have reconstituted MMTV LTR DNA into a polynucleosome array using Drosophila embryo extracts. We show binding of purified GR to specific GR elements within a large, multinucleosome array and describe a GR-induced nucleoprotein transition that is dependent on ATP and a HeLa nuclear extract. Previously uncharacterized GR binding sites in the upstream C nucleosome region are involved in the extended region of chromatin remodeling. We also show that GR-dependent chromatin remodeling is a multistep process; in the absence of ATP, GR binds to multiple sites on the chromatin array and prevents restriction enzyme access to recognition sites. Upon addition of ATP, GR induces remodeling and a large increase in access to enzymes sites within the transition region. These findings suggest a dynamic model in which GR first binds to chromatin after ligand activation, recruits a remodeling activity, and is then lost from the template. This model is consistent with the recent description of a "hit-and-run" mechanism for GR action in living cells (J. G. McNally, W. G. Müller, D. Walker, and G. L. Hager, Science 287:1262-1264, 2000).
Fletcher
T M
TM
Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-5055, USA.
Ryu
B W
BW
Baumann
C T
CT
Warren
B S
BS
Fragoso
G
G
John
S
S
Hager
G L
GL
D016475:3T3 Cells; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003850:Deoxyribonuclease I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004587:Electrophoresis, Agar Gel; D006367:HeLa Cells; D006801:Humans; D006868:Hydrolysis; D008024:Ligands; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009707:Nucleosomes / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D020079:Terminal Repeat Sequences; D014162:Transfection
D002843:Chromatin; D008024:Ligands; D009707:Nucleosomes; D011965:Receptors, Glucocorticoid; D000255:Adenosine Triphosphate; D003850:Deoxyribonuclease I