Fluorescence-labeled reporter gene in transgenic mice provides a useful tool for investigating cutaneous innervation.

B6.Cg-Tg(Thy1-YFP)16Jrs/J transgenic mice were created to express the yellow fluorescent protein gene driven by a mouse Thy1 promoter that labeled motor and sensory neurons such that individual nerves could be followed. These mice were used to identify nerves in the skin that innervate the erector pili and panniculus carnosus muscle. Whole mounts demonstrated yellow fluorescent protein expression in nerves of the skin, which was confirmed by labeling the neuromuscular junction with fluorescinated α-bungarotoxin. Frozen and paraffin-embedded skin sections revealed innervation of the panniculus carnosus muscle. Paraffin sections labeled with an anti-green fluorescent protein antibody revealed innervation of the panniculus carnosus as well as the erector pili muscle and around the hair follicle bulge.