A-D. Compared to wild-type (A,C), E17.5 Erk1/2CKO(Wnt1) (B,D) L4 DRG cross sections revealed a massive decrease in DRG size as indicated by the gross morphology and decreased number of cells expressing neuronal markers. (Scale bar=50μM)
E-F. Whole mount neurofilament labeling of E15.5 control (E) and mutant (F) embryos revealed only sparse labeling in Erk1/2CKO(Wnt1) forelimbs, demonstrating that both motor and sensory projections are absent. (Scale bar=100μM)
G-J. Analysis of the expression of Parvalbumin and CGRP in P1 control (G,I) and Erk5CKO(Wnt1) (H,J) lumbar DRG cross sections did not show any gross change in DRG sensory neurons or in central projections within the spinal cord (arrows). (Scale bar=50μM)
K-L. Whole mount neurofilament immunolabeling of E14.5 control (K) and Erk5CKO(Wnt1) (L) forelimbs showed no differences in peripheral axon growth. (Scale bar = 100 μm) (See also Figure S1)