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. Author manuscript; available in PMC: 2019 Aug 27.
Published in final edited form as: Nat Cell Biol. 2009 Aug 16;11(9):1093–1102. doi: 10.1038/ncb1922

Figure 1.

Figure 1

GR-MMTV promoter interactions in response to ultradian corticosterone fluctuations. (a) Corticosterone plasma levels in a freely moving rat show ultradian (pulsatile) fluctuations. (b) Pulsatile corticosterone treatment induces cyclic GR loading at the MMTV promoter array (green) in the 3617 cell line (single cell analysis). Scale bar, 2 μm. (c) GFP-GR intensity fluctuations at the array in response to the changing hormone concentration (in the cell presented in b). (d) GFP-GR dissociation from the array in response to hormone withdrawal (measured by the GFP-GR fluorescent intensity at the ChRFP-NF1-marked locus) is completed in < 10 min, whereas GR remains nuclear for > 3 h. Error bars represent the mean ± s.e.m., n = 25 cells. (e) Representative ChIP experiment demonstrates a similar rate of dissociation of endogenous GR from the MMTV promoter array on hormone withdrawal. (f) GFP-GR dissociation from the MMTV promoter is completed in <15 min after hormone withdrawal when the activating hormone is a naturally occurring glucocorticoid (corticosterone or hydrocortisone), but is incomplete for all of the synthetic glucocorticoids tested, indicating stronger and longer-lived interactions between the synthetic hormones and the GR. Error bars represent the mean ± s.e.m., n ≥ 300 cells.