Fig. 3. Assessment of M-CAM expression in human fetal and adult-derived muscle cells. Quantitative real-time PCR for M-CAM cDNA in human fetal- (A) and adult (B)-derived muscle cells. GAPDH was used as an internal control. (C) Fold change in M-CAM expression in fetal and adult myoblasts. The difference in delta Ct between fetal versus adult M-CAM cDNA is 2.5, which translates to 5-fold upregulation of M-CAM transcript in human fetal cells compared with adult cells. Mb, myoblast. (D-F) Immunofluorescence staining for M-CAM (red) on cytospins of cultured fetal (E) or adult (F) muscle cells. Nuclei are counterstained with DAPI (blue). (D) Negative control (secondary antibody alone) of fetal muscle cells. All images were obtained at the same exposure to allow visual comparisons between samples. Magnification, 400x (D-F).