Fig. 5. The pCC growth cone stalls in Ptp52F mutants. Dissected embryos stained with mAb 1D4. (A) wild-type, late stage 12. aCC growth cones (a) have just begun to turn outwards. The pCC growth cone has already grown onto the 1D4-positive LG5 cell (bracket) in the hemisegments on the right (indicated by parallel lines flanking the pCC axon connection to LG5). (B) Ptp52F^18.3, early stage 13. The aCC growth cone (a) has already turned posteriorly and then begun to extend away from the CNS, but the pCC growth cones (p) have still not reached LG5. (C) Wild-type, early stage 13. The aCC growth cone (a) is at the same position as the one indicated in B. A continuous longitudinal pathway has formed. pCC axons are indicated by flanking parallel lines. (D) Ptp52F^18.3, late stage 13. The aCC axons (a) have already extended beyond the edges of the panel, but there are still gaps in the longitudinal pathways on the left side (arrows) just anterior to the pCC cell bodies.