Figure 5.

Inhibition of BMP signaling triggers immediate cell cycle exit of satellite cells. (A) Prior to the induction of differentiation, cultures of proliferating satellite cells were supplemented for 2 hours with BrdU and cultured for 3 days in differentiation medium. Myonuclei within MHC-positive myotubes from control cultures (B-C) show weak BrdU signals, while Noggin-treated myonuclei (D-E) show BrdU signals of stronger intensity in MHC-positive myotubes. (F) Analysis of the mean fluorescence intensity of the BrdU signal of Noggin-treated cultures (red columns; n = 92 myonuclei) compared to control cultures (black columns; n = 117 myonuclei). Histogram showing a shift in the frequency of Noggin-treated cells to higher levels of BrdU (p < 0,005; Wilcoxon test).