Fig. 2

Innervation defects are due to precocious nerve arrest. (A–C) Nerve interruption at L3, in 4-dpf gdnf, ret1-MO1 double morphant fish. Nerve arrest (A) is associated with the formation of precocious intercalary neuromasts distal to the interruption (B and C). (D and E) Nerve interruption in double morphant embryos is manifest at a time when the primordium is still migrating in photoconverted Huc:kaede, cldnb:gfp (D) or in Huc:kaede, cxcr4b:rfp (E, arrowhead marks the nerve ending) embryos. (F and G) Arborization of sensory neurites accompanying the migrating primordium at 35 hpf in a control (F) and a gdnf, ret1-MO1 double morphant embryo (G). (H) Nerve lagging behind the primordium (arrow) in an nbt:dsred, cldnb:gfp embryo injected with 0.15 mM ret1-MO2. L1 is about to be deposited. E and H are composite pictures assembled from two consecutive planes in Z-stacks. Anterior is left in all panels, and the primordium is migrating to the right in D–H. (Scale bar, 100 mm.)