Fig. 1

Adult Epidermal Innervation Requires Erbb3b and Adgra2

(A) Left, diagram of adult skin anatomy. Right, confocal projection and orthogonal views through the lateral trunk. Yellow lines, planes of orthogonal sections. In this and subsequent lateral views, posterior is to the right.

(B) Timeline of trunk skin development with approximate timing of major morphogenetic events. See Figure S3A for timing of differentiation of club cells, a specialized cell type within the fish epidermis (Whitear, 1986). ^∗shown in this study; ^†based on (Guzman et al., 2013); ^‡based on (Sire et al., 1997a).

(C and D) Projections and orthogonal views through the epidermis of isolated scales. P, periderm; BC, basal cells.

(E and F) Transverse sections through the mid-trunk. In this region, DRGs are located dorsal to the spinal cord (Weis, 1968). Double-headed arrows, DRG central axons within the spinal cord (sc). Dashed lines, spinal cord boundary.

(G and H) Lateral views of intact adult trunk skin. Dashed lines, scale margins. Arrows, superficial axon bundles above scales.

(I–K) Representative images of lateral trunk skin from adults of indicated genotypes. Inset in (J), trigeminal sensory axons over the eye to confirm presence of transgene.

Transgenes: (A) keratinocytes (Tg(krt4:EGFP)) (Rasmussen et al., 2015) and osteoblasts (Tg(sp7:mCherry-nfsB)) (Singh et al., 2012); (C) keratinocytes (Tg(actb2:BswitchR)) (Kobayashi et al., 2014); (C, E, and G) and somatosensory neurons (Tg(p2rx3b:EGFP)) (Kucenas et al., 2006); (D, F, and H) Tg(-28.5Sox10:Cre);Tg(ubb:GswitchR) (Kague et al., 2012, Mosimann et al., 2011); (I–K) somatosensory axons (Tg(p2rx3a>mCherry)) (Palanca et al., 2013). Staining: (E and F) nuclei (DAPI). Scale bars, 100 μm (A and E–H), 10 μm (C and D), and 250 μm (I–K). See also Figures S1 and S2.