Fig. 1

Dynamic bioelectric currents and expression of Ca²⁺-related channels in elongating feathers. a Endogenous electric current density in anterior, posterior feather buds and interbud regions in intact chicken embryos at different developmental stages (n = 9–11 measurements per position per stage). Between Hamburger & Hamilton (H&H) Stage 34–35, the direction of currents at the anterior buds reversed from inward to outward, while that at the posterior buds stayed inward. The direction of currents at interbud regions stayed inward throughout the developmental stages examined. Data are presented as mean ± s.e.m. **P < 0.005 (two-sample Student’s t test). Scale bar, 500 μm. b Confocal image of H&H 31 and H&H 35 feather buds stained with LCAM and VIM to reveal distinct morphology of epithelial and mesenchymal cells. VIM positive cells in epithelium are melanocytes and periderm cells. Dashed lines highlight epithelial-mesenchymal boundaries. Scale bars, 50 μm. c Screening of genes encoding ion channels in RNA-Seq highlights multiple Ca²⁺-conducting channels. d In situ hybridization results of genes encoding components of VGCCs, gap junctions, CRAC channels, and Ca²⁺-activated K⁺ channels. Scale bar, 50 μm