Fig. 4. Co-detection of M-CAM with myogenic markers on tissue sections from 17-week human fetal muscle and from adult mouse muscle. (A) Co-expression of M-CAM (green) and M-cadherin (red, arrowheads) on a myogenic cell. (B,C) Expression of M-CAM (green) with Pax7 (red). Open arrowheads indicate M-CAM⁺ cells and filled arrowheads M-CAM-Pax7 double-positive cells. Arrow indicates a M-CAM^-Pax7⁺ cell. (D-F) Expression of M-CAM with MyoD. (D,E) M-CAM is detected in green and MyoD is in red. (F) M-CAM is in red and MyoD is in green. Note the presence of M-CAM⁺MyoD⁺ cells (arrows), M-CAM⁺MyoD^- cells (open arrowheads) and M-CAM^-MyoD⁺ cells (filled arrowheads). (G-I) Adult mouse skeletal muscle tissue sections stained with M-CAM (green, open arrowheads) and Pax7 (red, filled arrowheads). Note that Pax7 and M-CAM never co-localize to the same cell. Nuclei are stained in blue with DAPI. Magnification, 1000x (A,I); 630x (B-H).