Fig. 3

Loss of thsd7a impaired PAC, RoP axons and associated secondary motor neuron axons formation. Representative images showed the effect of Thsd7a knockdown on PAC angiogenesis and RoP neurogenesis by morpholino in Tg(kdr:EGFP/mnx1:TagRFP). Embryos were examined at 48 hpf (a-f) and 78 hpf (g-h). Anterior is to the left. a-c, g: Uninjected control. d-f, H: Embryos were injected with MO1 and MO2. Vasculature and motor neuron shown in green and red, respectively. PAC, RoP and MiP are indicated by arrows, open arrowheads and arrowheads, respectively. a, b: PAC and ROP axons were formed normally along HMS in control group. d: PAC was completely absent at HMS in morphants. e: RoP axons were absent at HMS. Moreover, MiP axons and some secondary motoneuron grew aberrantly. c, f: Merged images of panel a, b and d, e respectively. g: PAC and primary motoneurons grew normally. h: Some initially absent RoP axons reappeared but their trajectory were slightly shifted and PAC still absent. MiP axons were shorter with abberant outgrowth. Scale bar is 100 μm