Figure 4. Ligand-induced NOTCH activity prevents the diminution in the number of fetal muscle progenitors and the increase of muscle differentiation in immobilized fetuses.
Transverse sections of contralateral (A,C,E,G) and DELTA1/RCAS grafted (B,D,F,H) limbs of DMB-treated fetuses were hybridized with the DLL1 probe (A,B) to visualize ectopic DLL1 expression in right grafted limbs (B) or immunostained with PAX7 and MF20 antibodies (C–H) (N = 3). (I) The quantification of PAX7+ cell number per unit area and muscle area was performed in DELTA1/RCAS-grafted and contralateral limbs of the same immobilized embryos. Result was presented as percentage of contralateral limbs, in immobilization conditions. Error bars represent standard deviations of six sections originating from three independent experimental embryos. The p-value was calculated using the Wilcoxon test. Limb sections are dorsal to the top and posterior to the left. u, ulna, r, radius.
Figure 4—figure supplement 1. A continuous source of NOTCH ligand maintained the number of PAX7+ muscle progenitors despite the inhibition of muscle differentiation.
