Fig. 3

trkC1 expression is restricted to Rohon Beard cells not undergoing apoptosis. (A and B) Equivalent dorsal views of spinal cords of the same 26-hpf embryo initially labeled with HNK-1 (brown) and a probe for trkC1 (blue) and shown in (A). The embryo was then labeled by TUNEL to reveal dying cells (dark brown) and is shown again in (B). (A) trkC1 is expressed in a subpopulation of RB cells. The inset indicates one trkC1-expressing HNK-1⁺ neuron (a) and two HNK-1⁺ neurons that do not express trkC1 (b and c). (B) TUNEL labeling reveals that the trkC1-expressing RB cell (a) is not apoptotic. One of the HNK-1⁺/TrkC1^- cells (b) is apoptotic and one is not (c). None of the trkC1⁺ neurons were double labeled by TUNEL. Scale bar, 25μm. (C) Graph showing the different percentages of TrkC1⁺/TUNEL^-, TrkC1^-/TUNEL⁺, TrkC1/TUNEL^-, and TrkC1⁺/TUNEL⁺ RB cells in 26-hpf embryos (n = 5).