Fig. 4.

Pigmentation in an albino mouse (tyr−/−) after a nerve graft from C57BL/6Nf1+/− mouse. A, Dorsal view of the white skin of an albino host, showing absence of black hairs, 1 month after grafting of a 2.0 mm segment of nerve from a C57BL/6Nf1+/− mouse, followed by cut and deflection of the grafted nerve. The skin remains white, indicating absence of pigmented melanocytes in this mutant. B, Ventral side of the skin overlying the graft region showing pigmented spots in the skin.C, D, Two examples of pigmented cells (brown–black pigment granules) in cryosections within muscle overlying the grafted nerve segment after staining of sections with H&E to highlight nuclei and cytoplasm. In C, note the clusters of pigmented cells (arrows). InD, note the individual cells with visible nuclei and pigment granules in the cytoplasm (arrows). Scale bar (in D): C, D, 10 μm.