Fig. 8. FRAP on bound PcG proteins in the salivary gland nuclei. Individual bands in the salivary gland nuclei were photobleached and redistribution of fluorescence was measured over time. Recovery times (t₀, the time required for the fluorescence intensity to reach 63% of the final height of the recovery curve) were plotted as a histogram in A (blue, PhGFP; red, PcGFP). Redistribution of the fluorescence in both cases occurs in less than 6 minutes. (B) Lack of correlation between the concentration of binding sites and recovery time t₀. Individual nuclei where several loci were analyzed are color coded (solid colored symbols for PhGFP and open colored symbols for PcGFP). Data from simulations show a linear dependence of the t₀ on the concentration of binding sites (connected points for three different dissociation rate constants).