FIG. 6.

Increased neogenin expression impairs migration of neuroblasts from the subventricular zone. (A) Ex vivo overexpression of control IRES-GFP- or neogenin-IRES-GFP-expressing plasmids in E15 embryos. Embryos were sectioned at 250 μm and plated on poly-l-lysine-laminin-coated inserts. Cells were visualized at 24 h postelectroporation (red) to determine their baseline vector expression and migration. Cells were imaged again at 72 h postelectroporation to assess the degree to which they migrated (green). Under both control and neogenin-overexpressing conditions cells expressing the plasmids initially line the ventricle (red, arrows). After migration (lower panels) the cells move away from the ventricular zone into the striatum (green, arrows) in the control; however, in the mutant they fail to shift position. (B) Quantification of the capacity of cells to migrate depicted in panel A. In order to quantify migration, fold increase was obtained by calculating (total migration − initial migration)/total migration and then normalizing values to wild-type migration levels. Error bars represent standard error of the mean (n = 5 for the control and n = 6 for the mutant, with two sections per embryo). Significance was determined through a paired two-tailed t test of control versus neogenin-overexpressing slices. *, P < 0.05.