The site of action of the asebia locus (ab) in the skin of the mouse

Abstract

Summary: In mice homozygous for the asebia mutation (ab^J/ab^J) the sebaceous glands were small and the sebaceous cells abnormal, the fully grown hair follicles were twice as long as those in wild-type (+ / +) mice, the catagen and telogen follicles were abnormal and, because the active phase of the hair cycle was longer than in + / + mice, the initiation of the second hair cycle was delayed. The abnormalities in the sebaceous glands and in catagen and telogen follicles were also present in ab^J/ab^J embryonic skin grown on a nude host but anagen of the second hair cycle commenced at about the same time in ab^J / ab^J and + / + grafts. When recombinants incorporating mutant or wild-type epidermis and dermis were grown on a nude host, the abnormalities in the sebaceous glands and the catagen and telogen follicles were only observed in the recombinants incorporating ab^J / ab^J epidermis. It was concluded that mutant activity in the epidermis was responsible for the abnormalities in the sebaceous glands and in catagen and telogen follicles and that mutant activity at some site distant from the skin was responsible for the abnormalities in the timing of the hair cycles.