Fig. 6

Ectopic expression of robo3a.1 is sufficient to induce medial displacement of HTS axons. (A-F′′,H-M′′) Dorsal views of confocal z-projections of brain regions of 48 hpf (A-F′′) and 72 hpf (H-M′′) embryos. Anterior is towards the to left. (A-B′′,H-I′′) Heat-shock treatment does not affect pathfinding of otpb:gfp or hcrt:tdtomato longitudinal axon in control embryos. (C-D′′,J-K′′) Longitudinal otpb:gfp or hcrt:tdtomato axons are medially displaced after heat shock-induced overexpression of robo3a.1. (E-F′′,L-M′′) Pathfinding of otpb:gfp or hcrt:tdtomato longitudinal axons is normal after overexpression of robo3b.1. (G,N) Quantification of the number of otpb:gfp or hcrt:tdtomato longitudinal axons in defined outer or inner sections. Brackets in B,B′,D,F, I,I′,K,M, indicate outer and inner sections as defined by Mauthner neuron somata (outer section) and the area in between (inner section) used for quantification. Asterisks and plus signs indicate longitudinal HTS axons in outer and inner sections, respectively. Scale bars: in A, 50 μm for A,C,E,H,J,L; in B, 25 μm for B-B′′,D-D′′,F-F′′,I-I′′,K-K′′,M-M′′.