DMob4 mutant third-instar larvae have supernumerary boutons at NMJs. NMJ morphology revealed by anti-HRP staining is shown for control (A), DMob4EYΔL3/Df(2R)42 (B), ElavGal4;DMob4EYΔL3;UAS–DMob4 rescue (C), and Dap160EMS1/Δ2 mutants (D). E, Mean satellite bouton number at muscle 6/7 and muscle 4 for various DMob4 allelic combinations and controls. Error bars are SEM. Scale bars, 10 μm.