Fig. 2. Reversibility of chromatin accessibility changes due to hyperacetylation. (A) Time series of HeLa cell nuclei with microinjected 464 kDa dextrans (green) and Hoechst DNA stain (red) before TSA treatment, after 3 or 17 hours TSA incubation and 3 or 4 hours after removal of TSA. The dashed lines indicate the direction of the corresponding linescans, which are shown adjacent to the images. Scale bars, 10 µm. (B) Kinetics of chromatin decondensation due to TSA-induced histone acetylation. The increase of the chromatin correlation length represents the induced decondensation. The fit curve is a single-exponential reaction kinetics with a half-time of 3.5 hours.