FIGURE 1

FIGURE 1

Plexin B3 is expressed in retinal ganglion cells when retinal axons are crossing the midline. In situ hybridization was performed on Tg[Isl2b:GFP] transgenic embryos at 34–36 hpf (hour post fertilization), in which the reporter protein GFP is expressed specifically in retinal ganglion cells and can also label retinal axons. (A) Fluorescent in situ hybridization using complementary RNA probe reveals that Plexin B3 is strongly expressed in retina at 34 hpf. (B) Tg[Isl2b:GFP] transgenic labeling demonstrates that Plexin B3 is strongly expressed in retinal ganglion cell layer (square brackets) when pioneer retinal axons are starting to cross the midline and form the chiasm. (C,D) Plexin B3 is expressed in retinal axon ganglion cell layer at 36 hpf when many retinal axons cross the midline. (E,F) A zoomed in and single plane of confocal image demonstrates that Plexin B3 is expressed in retinal ganglion cell layer. All images are ventral view, rostral to the top. Scale bar, 100 μm.