Genetic interaction of lola and spire mutations. Stage 17 embryos of the indicated genotypes were fixed and stained with anti-Fasciclin 2 to label ISNb motor axons, and visualized by peroxidase histochemistry. Three representative hemisegments are shown in each panel. (A) Wild type (WT). ISNb forms three neuromuscular junctions (NMJs) to ventral longitudinal muscles per hemisegment (arrows). (B) spir1 homozygous mutant. NMJs are indicated with arrows, positions where NMJs are missing are highlighted with asterisks. (C) lolae76/lolac46 null mutant. (D) lolae76spir1/lolac46 embryo. Note partial restoration of NMJs. (E) Quantification of NMJ number in embryos of the indicated genotypes. Average number of NMJs per hemisegment is plotted as blue bars. Thin lines indicate standard error of the mean of three experiments (N = approximately 200 hemisegments per dataset).