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Fig. 1 | Neural Development

Fig. 1

From: DSCAM is differentially patterned along the optic axon pathway in the developing Xenopus visual system and guides axon termination at the target

Fig. 1

Distribution of DSCAM in a ventral-to-dorsal gradient along the optic nerve and chiasm of stage 45/46 Xenopus tadpoles. a Coronal section of the Xenopus tectum and optic nerve immunostained with DSCAM (red; right and left panels) and 3A10 anti-neurofilament (green; left panel overlay) antibodies. b Higher magnification image of the optic nerve shows high DSCAM immunoreactivity ventrally along the optic nerve bundle, while 3A10 antibody preferentially stains fibers along the dorsal region of the optic nerve (overlay; white dotted line). c Coronal section at the level of the optic chiasm (white arrowhead), shows DSCAM immunoreactivity localized to fibers at the ventral base of the chiasm (white arrowhead), while 3A10 immunopositive retinal fibers cross the optic chiasm more dorsally (white dotted line). Note the more diffused, punctate DSCAM immunoreactivity in the brain at the level of the optic tract (arrow) where RGC axons begin to defasciculate and project contralaterally past the chiasm. d, e The average fluorescence intensity of DSCAM and 3A10 immunoreactivity was measured along the ventrodorsal axis of the optic nerve and optic chiasm using a 3.5 μm diameter ROI using MetaMorph. Six or seven measurements using the circular region tool were obtained along the ventrodorsal axis, with five sets of measurements obtained at distinct locations along the optic nerve or chiasm (n = 4 tadpoles, with at least two tissue sections per tadpole). d Plotting mean fluorescence intensity (normalized per channel and per sample) along the optic nerve revealed a high-ventral to low-dorsal distribution of DSCAM immunoreactivity while 3A10 immunoreactivity was higher dorsally (difference for Distance p = 0.011; Distance x Fluorescent Channel p ≤ 0.001; two-way ANOVA). e Quantification of the mean fluorescence intensity shows a high-ventral to low-dorsal distribution of DSCAM immunoreactivity at the optic chiasm (difference for Distance p = 0.003; Distance x Fluorescent Channel p ≤ 0.001; two-way ANOVA). Scale bars: 40 μm for a; 20 μm for b, 50 μm c

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Neural Development

ISSN: 1749-8104