Increasing divalent cation concentration leads to an increase in chromatin compaction in permeabilised cells.

<p>(A) FLIM images of permeabilised Hela^H2B-2FP cells with increasing Ca²⁺ concentration. There is a decrease in lifetime with increasing Ca²⁺ concentrations and an increase with the addition of 12 mM of EDTA. The increase in compaction is also seen with the fluorescence intensity image. (Scale bar –10 µm). (B) Average EGFP fluorescence lifetime normalised to the value of control cells are plotted against the varying concentration of Ca²⁺ and Mg²⁺. Error bars indicate standard deviation calculated for 16 and 15 cells respectively from 4 independent experiments.