The estrogen receptor alters large-scale chromatin structure
Anne C. Nye, Ramji R. Rajendran, Benita S. Katzenellenbogen and Andrew S. Belmont
Department of Cell and Structural Biology, University of Illinois at Urbana-Champaign
Re-condensation of chromatin induced by the estrogen receptor plus estrogen
A.C. Nye and A.S. Belmont
28 min, 1 frame min-1.
Frame width, 30 µm
In the absence of estrogen receptor (ER), the GFP-labeled chromosome arm in this cell line is a tightly condensed mass with a diameter of 1 µm (not shown). When the ER is targeted to this heterochromatin mass in the absence of its hormone, estradiol, the chromatin unfolds globally and locally, resulting in a dramatic increase in size of the chromosome arm as well as production of 'fuzzy' fibers. These unfolded fuzzy fibers are the starting point for the movie, which shows two cells right next to each other - the GFP-labeled chromosome arm in each is spread throughout about two-thirds of the nucleus. Surprisingly, estradiol caused this chromatin to rapidly condense not only locally, which resulted in the fibers becoming more distinct, but also globally, which resulted in an overall decrease in size within 30 min. (This work has been submitted.)