Fig. 8. Premature loss of the basal lamina in the Hes1;Hes5 double mutant. (A) In the wild type, the spinal cord and dorsal root ganglia (DRG, arrows) are clearly separated. (B) The basal lamina is formed at the outer barrier of the wild-type spinal cord (open arrows). (C) Neurons (TuJ1⁺) in the spinal cord and DRG (arrows) are clearly separated in the wild type. (D) In the double mutant, neurons (TuJ1⁺) in the spinal cord and DRG are intermingled (arrow). (E) In the double mutant, the outer boundary of the spinal cord is not clear. Some cells are erupted from the spinal cord (arrowheads). (F) The basal lamina is not formed at the boundary of the double-mutant spinal cord (arrows). (G,H) Neurons (TuJ1⁺) are erupted from the spinal cord (arrowheads), and some of them are intermingled with the DRG. (I-K) Laminin-1 is expressed at the basal side of radial glia (nestin⁺) in the spinal cord. (L) Laminin-1 mRNA is expressed in the ventricular zone. (M-O) In the double mutant, laminin-1 expression is lost from the ventral region where radial glia (nestin⁺) are lacking but is maintained at the dorsal boundary where radial glia still remain. Arrowheads indicate the end points of laminin-1 expression. (P) Expression of laminin-1 mRNA is lost in the ventral region of the double mutant. Scale bars: 100 µm in A,C,E,G,I-P; 100 µm in D,H; 10 µm in B,F.