Fig. 4

FCS analysis of chromatin dynamics. a HeLa cell expressing H2A–EGFP (transient) and H2B–mCherry (stable). The correlation plots show H2A–EGFP ACFs (green), H2B–mCherry ACFs (red) and their CCF (black) acquired in the nucleus (euchromatin—3) and in the cytoplasm (4), revealing significant cross-correlation in the nucleus, but not in the cytoplasm. Fitting them with a relaxation model for loop-rosette-structured polymers under theta-solvent conditions yielded a significant difference in relaxation time distribution between hetero-(1/2) and euchromatin (3) both for H2A (ch1) and H2B (ch2). b Untreated MCF7 cell expressing H1-EGFP. At the three positions (nuclear periphery—1, blue; nucleolar periphery—2, purple; euchromatin—3, orange), the corresponding ACFs were acquired. Fitting them like in a (res—residuals) yielded a significant difference in relaxation time distribution between hetero- (1, 2) and euchromatin (3). c Same as b, but cells were treated with TSA, resulting in globally increased relaxation times without significant differences between 1, 2 and 3. d Same as b, but cells were ATP-depleted, resulting in globally increased relaxation times without significant differences between 1, 2 and 3