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. Author manuscript; available in PMC: 2007 May 14.
Published in final edited form as: Dev Cell. 2006 Jan;10(1):105–116. doi: 10.1016/j.devcel.2005.10.017

Figure 2.

Figure 2

Hyperdynamic Binding of Architectural Chromatin Proteins in ES Cells (A) Fluorescence recovery after photobleaching (FRAP) to study the dynamics of chromatin-associated proteins. A heterochromatic (white arrow) region in cells expressing HP1α-GFP was bleached, and the recovery was measured. In each experiment, undifferentiated ES cells (top), cells 24 hr after LIF withdrawal (middle), and NPCs (bottom) were analyzed. The scale bar is 5μm. (B) FRAP curves of heterochromatin foci of transiently expressed HP1α-GFP. Heterochromatin recovery was significantly faster in ES cells compared to either NPCs or cells 24 hr after LIF withdrawal. (C) FRAP curves for transiently expressed H1°-GFP. (D) FRAP curves for transiently expressed H2B-GFP. Left: recovery kinetics over a period of 10 min in undifferentiated ES cells (empty circles), cells 24 hr after LIF withdrawal (gray circles), and NPCs (black circles). Middle: the first 200 s are enlarged and are shown with error bars. Right: estimated mobile fractions of undifferentiated ES cells (white), cells 24 hr after LIF withdrawal (gray), and NPCs (black). (E) FRAP curves for transiently expressed H3-YFP as in (D). (F) FRAP curves for transiently expressed H3.3-YFP as in (D). In (C)-(F), half of the nucleus was bleached, including heterochromatin and euchromatin regions. Values represent averages from at least 20 cells from 3 experiments ± SD.