Figure 3.

Senescence phenotypes in Brca1^Δ11/Δ11 embryos. (A–C) Photograph of acidic β-galactosidase staining of Brca1^Δ11/Δ11 (Mt) and Brca1^+/+ wild-type (Wt) E18 embryos. Strong staining was found in the tail (B) and limbs (C) of all tested mutant embryos (n = 6) that were E16.5 and older. (D,E) BrdU incorporation of Brca1^Δ11/Δ11 (D) and wild-type (E) E16 embryos in thoracic region. Mutant embryos contained fewer BrdU-positive cells than wild-type embryos. The boxed areas in D and E are shown in D‘ and E‘. To provide a quantitative comparison, BrdU⁺ cells in comparable areas equivalent to the size shown in D‘ and E‘ in wild-type (n = 4) and mutant (n = 4) embryos were counted and subjected to the T-test. The average number of BrdU⁺ cells was 118 ± 11.9 cells/area and 88.5 ± 12.2 cells/area in wild-type and mutant, respectively (p ≤ 0.017).