Fig. 7. The high contribution of mutant Pax3 cells to the dermomyotome results in a failure to maintain an organized epithelium. Transverse sections showing the dermomyotome of chimeric embryos at E11 at the limb level. (A-C) The dermomyotome appears highly organized. (A,C) the blue cells refer to chimeras generated from Pax3^+/- ES cells. (B) Section from a chimera derived from Pax3^-/- ES cells: there is no contribution of blue cells to the dermomyotome; however, the neural tube contains mutant cells (data not shown). In D-I, several transverse sections at the limb level are shown from chimeric E11 embryos with high contribution to the somite. They document the disorganized architecture of the epithelium made from blue Pax3^-/- cells. Four embryos were analyzed. DM, dermomyotome. Scale bar: 100 µm.