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Figure 5 | Neural Development

Figure 5

From: Neuropilin2 regulates the guidance of post-crossing spinal commissural axons in a subtype-specific manner

Figure 5

Loss of Neuropilin 2 (Npn2) leads to a decrease number of post-crossing, Atoh1-tauGFP-positive spinal commissural axons. (A, B) Confocal micrographs representing the marginal zone (post-crossing axon-containing planes) of open-book preparations derived from either Npn2 −/+ (A) or Npn2 −/− (B) embryos harboring the Atoh1-tauGFP reporter. Note the paucity/absence of axons projecting away from the midline in the open-book preparation generated from the Npn2 null embryo. (C) To assess the pathfinding behavior of labeled post-crossing dI1 axons in Npn2, Sema3F and Sema3B null mutant embryos, open-book preparations were derived from homozygous and heterozygous embryos for each line, and the samples were imaged using confocal microscopy. The outermost seven planes (0.5 mm per plane from the underside or ventral-most region of a given open-book preparation) were considered to represent the marginal zone and the areas of GFP-labeled pixels occupying the ventral funiculi (VF, defined as region from FP to 50 μm lateral to the FP) or the lateral funiculi (LF, defined as region located 50 to 200 μm lateral to the FP) were measured. GFP intensity was then averaged across all regions and the relative areas of GFP labeling were compared in homozygous and heterozygous samples. As shown in the bar graph, a statistically significant change/decrease in the area of GFP-labeled pixels, which reflects a reduced number of post-crossing dI1 axons projecting away from the FP, was only observed in the LF of Npn2 knockout animals. The data are derived from 4 to 5 embryos per genotype. Student’s T-test , P <0.01. Scale bar in B is 25 μm for A-B.

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