Partial denervation and extensive sprouting at Dox-treated imKO NMJs. In control NMJs, AChR clusters were completely innervated by nerve terminals labeled by neurofilament (NF) and synaptophysin (syn) (green). The NMJs were covered almost entirely by terminal Schwann cells and their processes (labeled by S100β in cyan). None or negligible sprouting was observed for nerve terminals and Schwann cell processes (A, B). In Dox-treated imKO mice, NMJs became fragmented and lost innervation (pink arrow); yellow represents lost innervation and AChR clusters. Stars indicate sprouting of nerve terminals and Schwann cells; n = 30 for each genotype. **p < 0.01 (Student's t test). Scale bar, 10 μm.