Fig. 6

DUX4 and MYOD partially co-localize in hypotrophic FSHD fibers. The FSHD muscle sections were treated as in Fig. 3 with anti-DUX4 MAbs 9A12 (A, B) or E5-5 (C) (red) and anti-laminin-α2 serum (purple), observed by epifluorescence (A, B) or confocal microscopy (C). A, B 9A12 immunostaining reveals several dots either in the nuclei, sarcoplasm or at the fiber periphery of either hypotrophic fibers, some < 15 µm), that can be found in cluster (A and B: top and bottom panels), or normal-size fibers (B: middle panels). At the fiber periphery, 9A12 staining can be observed near/inside two close nuclei (or a cluster of them, circle) that are in 2 adjacent fibers. The arrow indicates an abnormal tip next to 9A12 staining. Large or punctuated laminin defects are pointed by yellow arrows or arrowhead, respectively, and some of their ‘ends’ correspond to a stronger DUX4 signal. A corresponds to magnification of a region indicated by a star in Fig. S11A. C Co-immunodetection of DUX4 (E5-5 MAb) and MYOD (5.8A MAb). Some rare DUX4 staining was found at the periphery of myofibers (confocal microscopy). DUX4 is partially co-detected in dots with MYOD and laminin-α2 around a large peripheral nucleus. However, two DUX4 dots (arrows) do not show laminin-α2 staining and the right dot partially co-localizes with MYOD