Fig. 2

Blocking peptides result in pathfinding failures. In panels B, E, and H, black arrowheads mark the choice point and black arrows mark the most ventral extension of the CaP motoneuron axon. (A–C) Analysis of control peptide injected embryos. (A) Whole body image of an embryo injected with the control peptide showing the normal body axis. (B) Normal primary motoneuron projections. (C) Quantitation of CaP neural types in control peptide injected embryos, showing type 2 and 3 neurons confined to caudal somites as in uninjected embryos. (D–F) Analysis of embryos injected with phosphotyrosine containing peptide. (D) Whole body image of an embryo injected with the phosphotyrosine containing peptide showing foreshortened anterior axis with subsequent fore and mid-brain defects. (E) Primary motoneuron projections showing forestalled ventral CaP axon projections. (F) Quantitation of CaP neural types showing stalled type 2 and 3 neurons in rostral as well as caudal somites. (G–I) Analysis of embryos injected with phosphomethyl-Phe containing peptide. (G) Whole body image showing foreshortened anterior axis with subsequent fore and mid-brain defects. (H) Primary motoneuron projections showing forestalled ventral CaP axon projections. (I) Quantitation of CaP neural types showing stalled type 2 and 3 neurons in rostral as well as caudal somites. In all images, rostral is to the left, and dorsal is up.