Cross sections of EDL muscle from an NMB rat showing Myf-5 (green), MyHC type I (red) and nuclei (blue). Myf-5 shows a clear nuclear localization and a predominant staining in the cytoplasm of type II fibers. (A) Myf-5 staining only, (B) composite view of all fluorophores, scale bar 50 µm. A higher magnification of the area in (A) and (B) is shown in (C) and (D). Some nuclei are intensely stained for Myf-5 (arrows) while it is absent in others (arrowhead), scale bar 20 µm.