Figure 2

Disorganized L6 neuronal morphology in reeler and scrambler explants and rescue by Reelin injection. Hoechst nuclear stain (first column) reveals normal CP that forms during the 2 DIV culture period in wt (A) explants but not in r/r (B) or s/s (C) explants that were injected with Ct-CM. GFP expressing neurons (second column) show normal radially oriented neurites in wt (A) explants, but tangentially oriented processes in mutant (B, C) explants. 3-D rendering of imaged neurons (third column) confirms the radial and tangential orientations of L6 neurons observed in wt (A) and mutant (B, C) explants, respectively. Golgi/GM130 immunofluorescent labeling (fourth column) revealed elongated, pia-oriented Golgi colocalized to the apical neurite of L6 neurons in wt explants (yellow arrowheads; A), while condensed juxtanuclear Golgi were observed in both r/r Ct-CM and s/s Ct-CM mutant explants (blue arrowheads; B and C). (D) Within four hrs of exogenous Rln-CM injection into r/r explants, GFP + L6 neurons were oriented towards the pial surface in a clearly definable CP, demonstrated neurite elaboration into the MZ, and revealed elongated, pia-oriented Golgi colocalized to the apical neurite (yellow arrowheads). Purple asterisk represents traced neurons in 3-D rendering (third column). The single green line of the 3-D rendered traced neuron represents the primary neurite, while purple lines represent remaining neurites and corresponding branches. Scale bars: 20 μm in (A-D). Abbreviations: MZ, marginal zone; CP, cortical plate; SPP, superplate; IZ, intermediate zone.