Fig. 6: Deletion of Trp53 rescues hair regeneration defect in Mcl‑1‑deficient mice.

A, B Confocal analysis of HFs from FVB mice at P60, sampled at 0, 2, 4, and 6 days post depilation (dpd) to induce hair regeneration. Increased DNA damage (pH2A.X⁺) is evident in HF cells post‑depilation (A). Basal layer marked by KRT14, hair matrix by PCAD, DAPI as nuclear counterstain. DNA damage observed in a subset of CD34⁺ and KRT15⁺ HFSCs at 4 dpd (B). Data represent n = 3 mice per time point. Scale bars, 50 µm. C Experimental strategy for hair regeneration assay in adult K5‑Cre^ER/Mcl‑1^f/f/Trp53^flf mice. Mcl‑1 and Trp53 deletion was induced via tamoxifen‑containing diet between p55‑p62. A portion of the dorsal skin was shaved and waxed to induce hair regeneration. Dorsal skin samples were harvested at the indicated timepoints for analysis. D qPCR analysis showing reduced Mcl‑1 and Trp53 transcript levels in HF cells (CD49f⁺/SCA‑1^–) isolated from K5‑Cre^ER/Mcl‑1^f/f/Trp5^f/f mice, compared to littermate control. n = 2 mice per genotype. E Representative H&E‑stained histological sections of dorsal skin harvested at 9 dpd. n = 6 mice per genotype for each timepoint. Scale bars, 100 µm. F Representative images of mice taken at 0, 15, 30 dpd. n = 3 mice per genotype for each timepoint. G, H Confocal microscopy images of HFs from K5‑Cre^ER/Mcl‑1^f/f/Trp53^flf mice and littermate controls at 9 dpd, showing efficient CRE‑mediated recombination with upregulation of hCD4 (G) and downregulation of MCL‑1 (H). n = 6 mice per genotype for each timepoint. Scale bar, 50 µm. Basal layer is stained by KRT14, hair matrix stained by PCAD and DAPI as a nuclear counterstain.