Roles of K-channel activity in feather bud morphogenesis.

Bioelectricity plays a key role in shaping tissues during early development. We previously demonstrated that elongating chicken feather buds establish a transient standing electrical current loop, with calcium channel-mediated inward current at the bud tip driving collective distal dermal cell movement that orients feather bud growth. Here, we evaluate the hypothesis that potassium channels carry the outward current at the bud base. We found potassium channel inhibition converts periodic feather primordia into horizontal stripes and alters bud aspect ratios by disrupting the bud elongation process. Bioelectric measurements show disruption of the entire current loop, affecting both outward current at the base and inward current at the feather bud tip. Hexagonally arrayed bud patterns become horizontal stripes and buds with irregular contours. In situ hybridization shows a thinner dermal condensation layer and failure to form distinct primordia. Despite disorganized morphology, dermal cells still express feather markers (NCAM, TnC, DKK1 and BMP4), and epidermis exhibits aberrant β-catenin, Shh, EDA and EDAR expression patterns. These findings show that potassium channel activity is required to couple cell fate specification with morphogenesis and highlight that ion channels are essential for cell-cell communication during periodic feather patterning and bud shaping.