Fig. 1. Development regulates the distribution of anti-acetylated tubulin immunoreactivity in the peripheral processes of Rohon-Beard neurons. The distribution of aat in the major peripheral processes was examined using whole-mount immunocytochemistry (see Materials and Methods). The peripheral processes of RB cells were viewed in the focal plane of the skin of embryos that had been mounted laterally. In all views, anterior and dorsal are towards the left and upwards, respectively. (A) At 27 hpf, aat immunoreactivity displayed a uniform, continuous distribution (arrows) within the major peripheral processes of RB neurons. Within the spinal cord, aat immunoreactivity was present in emerging spinal tracts and RB somata. At this time, the embryo has just developed the ability to respond rapidly to tactile stimulation. (B) At 36 hpf, the distribution of aat immunoreactivity within peripheral processes remained continuous and uniform. In the spinal cord, aat immunoreactivity was more intense within spinal tracts when compared with spinal tracts of 27 hpf embryos. (C) By 40 hpf, aat immunoreactivity within peripheral processes began to display an altered distribution consisting of varicosities (asterisks). However, continuous, uniform labeling (arrows) was still evident in some processes. Within the spinal cord, aat immunoreactivity remained intense. (D) At 48 hpf, aat immunoreactivity was now only present as varicosities in the peripheral processes of RB cells. Within the spinal cord, aat immunoreactivity was no longer present. Scale bar: 20 µm.
