Fig. 3

DNA accessibility and local compaction of α-satellite target sites. A Sketch representing the co-transfection of two TALEs targeting the D7Z1 α-satellite repeats. The FLAG-TALE (without effector) is transfected with the TALE-KDM4B or with the TALE-KDM4B-H188A or the TALE-GFP. Only the FLAG signal is quantified in the cells expressing the two constructs. B Boxplots showing the FLAG signal normalized in the cells co-expressing the TALE-KDM4B (blue) (n = 50 nuclei), the point mutant (orange) (n = 37 nuclei) or the TALE-GFP (white) (n = 31 nuclei). The dashed line represents a signal normalized equal to one. C Measure of the TALE foci area by super-resolution microscopy (PALM). U2OS cells were transfected with the TALE-KDM4B-Dendra2 (top) or the TALE-KDM4B-H188A-Dendra2 (bottom). Cells are visualized in classical epifluorescence after an excitation at 488 nm (left, green), and super-resolution images reconstructed after photoactivation (405 nm) and excitation (561 nm) of Dendra2 single-molecule events (middle). Zoom of foci are presented on the right, as well as some examples of segmented foci. Scale bar, 5 µm and 0.5 µm for the right panel, segmented clusters images are 1 µm × 1 µm. D Boxplots representing the measure of the area of foci segmented of the TALE-KDM4B-Dendra2 (blue) (n = 27 foci) or the TALE-KDM4B-H188A-Dendra2 (orange) (n = 36 foci), with median values of 0.022 µm² and 0.018 µm² for the TALE-demethylase and TALE-inactive, respectively