Figure 1.
(A) Localization image of histones H2B in the nucleus of a human fibroblast cell labeled with emGFP. The localized fluorophores are blurred with a Gaussian corresponding to their individual localization accuracy. (Insets) Magnifications (4×) of the outlined areas. (B) A conventional wide-field image of the same nucleus as in A. The image was acquired in the conventional epifluorescence microscopy mode. (C) Localized histones of a different fibroblast cell after data processing. Each localized fluorophore is represented by a blue point. The average number of detected points is 124/μm2. (D) Result of the segmentation procedure. Gray regions are not included in the data analysis. The image is segmented based on a density threshold procedure to exclude regions outside the nuclear membrane as well as chromatin-depleted regions inside the nucleus, e.g., nucleoli.