The Journal of Neuroscience, October 13, 2004, ():
Fgf8 Regulates the Development of Intra-Neocortical Projections
J. Neurosci. Huffman et al.
24: 8917
Supplemental data
Files in this Data Supplement:
- supplemental material
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Supplemental Figure 1
a-f and a'-f' shows the DiI and DiA placement sites in the neocortex of Fgf8+/ (6 of 8 cases shown)and Fgf8neo/neo (6 of 8 cases shown) brains. a/a'-f-f' correspond to a/a'-f-f' cases reconstructed in Fig. 6. To systematically define dye placement sites, a digital image of the hemisphere was taken and a pre-constructed grid was superimposed on the image to determine dye placement location. This grid was used for consistent reliability of injection site location across cases. Once the position for dye insertion was determined, a small hole was made in the pia at the injection site, using a 36 gauge syringe needle-tip, and the DiI or DiA crystal was inserted into the cortical tissue, through the superficial and middle layers of the cortex. Care was taken to avoid penetration of the crystal into the underlying white matter.
- supplemental material
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Supplemental Figure 2
Digital images of coronal sections stained with DAPI, showing landmarks used for correlation of in situ data with axon projection data, and for reconstruction of ‘flattened’ neocortices. a: (I in figures 1, 5, 6) rostral pole of the superior colliculus; b: (II in figures 1, 5, 6) rostral pole of the hippocampus; c: (III in figures 1, 5, 6) anterior commissure. Dorsal is up and lateral is to the right.
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Supplemental Figure 3
Changes in the laminar organization of retrogradely labeled neurons at P0, P2, P5 and P8, observed in coronal (left column) and saggital (right column) planes of section, in wild-type mice. There is progressive distinction of lamina (clearly distinct by P8) of retrogradely labeled pyramidal-shaped neurons, as well as maintenance of strong labeling in layer 1. 1 of 3 cases are shown for each age.
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Supplemental Figure 4
Rostral to caudal series of coronal sections from Fgf8neo/neo cortices injected with DiI (red star) and DiA (green star), at 3 different ages: E16.5 (row a), E18.5 (row b), and P0 (row c). Unlike in wild-type brains (Fig. 3), cells in the caudal cortex are retrogradely labeled by dye in the rostral cortex.
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Supplemental Figure 5
DiA-labeled coronal sections from P0 Fgf8+/neo (A) and Fgf8neo/neo (a’) showing a defect in the crossing of the corpus callosum (CC) in the mutant, which has a Probst Bundle (PB).
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Supplemental Figure 6
Schema representing the hypothetical mechanism underlying the defect in axon projections in the Fgf8 mutant. Tangential projections of caudal and rostral neurons are shown; cells are green if they have retrograde labeling from caudally placed DiA; cells are red if they have retrograde labeling from rostrally placed DiI. Neurons located in caudal and rostral areas of the developing neocortex rarely grow axons that cross the middle. The blue (caudal) and green (rostral) background color represents the postulated molecular cues that contribute to segregating axon growth from caudal and rostral neurons. The yellow zone at the rostral pole represents Fgf8 expression, which controls molecular properties in the rostral cortex. In the Fgf8neo/neo hypomorph, reduced Fgf8 expression leads to rostral expansion of caudal molecular properties (blue), and thus axons from caudal neurons can grow into more rostral regions. The axons from rostral neurons remain sensitive to the non-permissive environment of the caudal cortex.
