Fig. 7. Math1 promotes cell movement out of the ventricular zone while Zic1 maintains cells within this zone, both at the expense of neural crest cells. Neural tubes of HH12 chick embryos were electroporated (right side as shown) with CMVpN1-EGFP alone (A,B), with Math1 (C,D) or with ^mycZic1 (E,F) expression constructs and harvested at 48 hours. Whole-mount GFP images (A,C,E) or transverse sections imaged for GFP (green) and islet1 (red) immunofluorescence (B,D,F) are shown. The islet1 staining allows visualization of the motor pools (MN) and the neural crest-derived dorsal root ganglia (DRG). Arrows in A,B indicate clear GFP in DRG on the electroporated side with lower levels in DRG on the non-electroporated side. Math1 and ^mycZic1 biases cells away from DRG as seen in the near absence of GFP in this structure (C-F). Within the neural tube, GFP in controls spans the width of the neural tube (A,B), whereas Math1 overexpressing cells are biased towards the lateral tube where differentiated cells reside (C,D) and ^mycZic1 overexpression biases cells to the ventricular side where progenitors reside (E,F). The asterisks indicate the location of the apical surface of the neural tube. Arrows in D,F indicate DRG.