Fig. 7. Segmentation of the bound fraction and fitting of the FRAP curves. A confocal image of PhGFP in a salivary gland nucleus is shown in A. Inset: confocal sections for PhGFP and PcGFP salivary gland nuclei. (B) Segmentation of the bleach box area into bound and unbound fluorescence regions. (C,E) Plot of the intensity for all pixels (red curve), the 30% highest pixels, bound fraction (blue curve) and the 30% lowest pixels (green curve). (C) PhGFP. (E) PcGFP. (D,F) Fit of the bound fraction of the protein to a single exponential (blue curve). The height of the green curve (unbound component) differs for PhGFP and PcGFP. (D) PhGFP. (F) PcGFP.