Fig. 5. Dose-dependence and synergism of Nrp1a and Sema3D MOs. Innervation of the IPN was assayed by anti-Lov immunolabeling and confocal microscopy and the number of larvae lacking dorsal projections (% abnormal dorsal IPN innervation) was determined for each experimental condition. Error bars represent the s.e.m. from at least three independent injection experiments. For a given MO, high MO refers to the concentration that caused morphological defects and lethality in a large proportion of larvae (above 50%); optimal MO concentrations did not produce morphological defects or lethality above mock-injected larvae; low MO concentrations were at least 25% less effective than the optimal MO concentration at causing defective IPN innervation. Co-injection of low MO amounts for Nrp1a and Sema3D had a significantly greater effect than injection of either MO alone. For the total number of larvae assayed and other experimental details see Table 1.