p53 Involvement in the control of murine hair follicle regression.

p53 is a transcription factor mediating a variety of biological responses including apoptotic cell death. p53 was recently shown to control apoptosis in the hair follicle induced by ionizing radiation and chemotherapy, but its role in the apoptosis-driven physiological hair follicle regression (catagen) remains to be elucidated. Here, we show that p53 protein is strongly expressed and co-localized with apoptotic markers in the regressing hair follicle compartments during catagen. In contrast to wild-type mice, p53 knockout mice show significant retardation of catagen accompanied by significant decrease in the number of apoptotic cells in the hair matrix. Furthermore, p53 null hair follicles…