Homozygous padi2 mutants are viable and have increased neuromuscular junctions. (A) Genotype frequency of 5 dpf larvae of incrossed padi2 heterozygotes. (B) Genotype frequency of adult offspring of incrossed padi2 heterozygotes. Data in A and B are from four and six clutches, respectively, and analyzed by χ² tests. (C) Representative images of slow-muscle fibers immunostained with α-MyHC antibody in the trunk of 5 dpf larvae from three independent replicates. (D) Representative images of the trunk of phalloidin-stained 5 dpf larvae for visualization of F-actin in fast-muscle fibers. WT cousin (left) and padi2^−/− (right) from three independent replicates. (E) Neuromuscular junctions are labeled with α-SV2 (green, presynaptic vesicles), α-BTX (red, postsynaptic AChRs), and merge (synapses) in WT cousins (top) and padi2^−/− (bottom) larvae at 5 dpf. (F) Quantification of the number of SV2 puncta, AChR puncta, and synapses in a single myotome in the trunks of larvae. Data are from three pooled independent replicates with the lsmeans (±) SEM and P values calculated by ANOVA reported. Each symbol represents a single myotome, and measurements were taken from two myotomes per larva (n = 100 myotomes from 50 WT larvae, n = 114 myotomes from 57 padi2^−/− larvae). Scale bars, 50 µm.