Pleiotropic effects of the nude mutation.

Mice homozygous for the autosomal mutation nude suffer from thymic dysgenesis, hairlessness and abnormal development of gonads and salivary glands. Their immunologic and reproductive defects can be overcome by grafts of whole thymus or thymic epithelium. Thymic replacement does not prevent or reverse the lack of hair growth. Skin from nude mice grafted to histocompatible or immune-suppressed phenotypically normal mice does not grow hair. Conversely, normal skin, successfully grafted to nude mice, maintains hair growth. Thus, the hairlessness of the nude mouse is not a secondary result of thymic dysgenesis; rather, it appears that thymus and skin have a single common defect.