Figure 4.

Measurement of the compaction state of nucleosome arrays. (A) tFCS signals (population median $\pm$ standard deviation) for 19×601 DNA molecules before nucleosome assembly (blue) and for chromatinized 19×601 molecules with increasing histone occupancy are shown. Data were taken using a side-illumination configuration. (B) tFCS measurement of the MgCl₂-induced nucleosome arrays compaction is shown as a function of histone occupancy (top to bottom: bare DNA, 6, 53, and 79% saturated arrays). (C) The median ($\pm$95% bootstrap confidence intervals) diffusivity (left) and compaction score (right) of bare DNA and nucleosome arrays before and after addition of 2 mM MgCl₂ are shown. The asterisk indicates statistical significance (two-sided Wilcoxon rank sum test, p-value$<$0.01). To see this figure in color, go online.