Extended Data Fig. 7: Systemic injection of ligand dye-ligand saturates the abundant protein MeCP2-HT in most organs.

a, Schematic of the experimental procedures to test the saturation of MeCP2-HT. b-i, Organs harvested and imaged for pulse dye-ligand saturation (red), as evident by the lack of chase dye-ligand (orange) in the nuclei (blue) where MeCP2-HT is expressed. Top scale bar is 1 mm, bottom scales bars are 50 μm. j-k, Six coronal sections of an MeCP2-HT animal injected in vivo with JF₆₆₉-HTL (j) immediately followed by perfusion with JF₅₅₂-HTL (k) to check for saturation. All panels were converted to nM dye-ligand concentration and scaled to the same concentration. Only very dense cell body regions, highly enriched in MeCP2 (for example, i), show any chase dye-ligand staining, indicating the inability to saturate in vivo. n = 5 animals for the brain, n = 1 for the other organs.