Figure 1.

Chk2 deficiency partially rescues Trf1^Δ/Δ K5Cre associated phenotypes and lethality (A) Survival curve of Trf1^Δ/Δ K5Cre Chk2^−/− and Trf1^Δ/Δ K5Cre Chk2^+/+ mice. Statistical analysis was done by the Log-rank (Mantel–Cox) test. (B) Weight at birth of the indicated genotypes. (C) Representative images of newborns and 2-week-old mice of the indicated genotypes. (D) Percentage of newborns that show severe or moderate skin follicular atrophy, skin interfollicular dysplasia, esophagus dysplasia, and strong CK6 expression. Chi-square test was performed for statistical analysis. Severe follicular atrophy is characterized by a reduced number of hair follicle primordial that are completely undeveloped. Moderate follicular atrophy is characterized by a decreased differentiation degree as compared to wild-type. Interfollicular dysplasia is characterized by undifferentiated keratinocytes, cellular depolarization and hyperkeratosis. (E) Representative images of hematoxylin–eosin and cytokeratin 6 staining in newborn skin and esophagus of the indicated genotypes. Dysplasic areas are marked with an asterisk and undeveloped hair follicles with an arrow. *P < 0.05; **P < 0.01; ***P < 0.001.