Fig. 4. kbp is required autonomously in neurons for axonal outgrowth. (A,A') Lateral views of a chimeric larva generated by transplantation of dextran labeled wild-type cells (red) into a kbp^st23 mutant. Wild-type neurons in the PLLg (arrow, A) extend axons along the entire length of the PLL (A'). Arrowheads point to extended PLLn axons and the rightmost arrowhead in A' represents an axon innervating the most posterior neuromast near the tip of the tail. (B,B') Lateral views of a chimeric larva generated by transplantation of dextran-labeled wild-type cells (red) into a kbp^st23 mutant. A single wild-type reticulospinal neuron in the hindbrain (arrow, B) extends an axon along the entire length of the spinal cord (B'). Arrowhead indicates the end of the axon near the tip of the tail.