Neural crest cell lineage restricts skeletal muscle progenitor cell differentiation through Neuregulin1-ErbB3 signaling.

Coordinating the balance between progenitor self-renewal and myogenic differentiation is required for a regulated expansion of the developing muscles. Previous observation that neural crest cells (NCCs) migrate throughout the somite regions, where trunk skeletal muscles first emerge, suggests a potential role for these cells in influencing early muscle formation. However, specific signaling interactions between NCCs and skeletal muscle cells remain unknown. Here we show that mice with specific NCC and peripheral nervous system defects display impaired survival of skeletal muscle and show skeletal muscle progenitor cell (MPC) depletion due to precocious commitment to differentiation. We show that reduced NCC-derived Neuregulin1 (Nrg1) in the somite region perturbs ErbB3 signaling in uncommitted MPCs. Using a combination of explant culture experiments and genetic ablation in the mouse, we demonstrate that Nrg1 signals provided by the NCC lineage play a critical role in sustainable myogenesis, by restraining MPCs from precocious differentiation.