Mouse BAZ1A (ACF1) Is Dispensable for Double-Strand Break Repair but Is Essential for Averting Improper Gene Expression during Spermatogenesis
Figure 3
Baz1a mutants can repair meiotic DSBs.
(A, B) Squash preparations of spermatocyte nuclei showing accumulation of γH2AX in response to meiotic DSBs, and its disappearance from autosomes as DSBs are repaired. Arrows, sex bodies; bar = 10 µm. (C) DMC1 focus counts on spread spermatocyte nuclei pooled from two sets of wild-type and mutant mice. Nuclei were staged by co-staining for the axial element protein SYCP3. Early zygotene was the only stage in which a statistically significant difference (P<0.05) was observed (P value from t-test; n = number of nuclei). (D) Spread chromosomes from Baz1a−/− pachytene spermatocyte showing MLH1 foci. (E) MLH1 focus counts pooled from two sets of wild-type and mutant littermates (P value from t-test; n = number of nuclei). (F) Primary/primordial and total follicles in Baz1a−/− and heterozygote littermate controls. Ovaries were dissected from one Baz1a−/− or two Baz1a+/− females at three months of age and stained with anti-MVH antibodies to detect oocytes. Baz1a+/− mice displayed no apparent phenotype in any of the cell types analyzed in this study, so they served as normal controls for these experiments. Each point is the number of follicles of the indicated type per histological section. (P values from Welch's t test; n = number of ovary sections.) (G, H) Anti-MVH-stained ovary sections from three-month old mice of the indicated genotypes. Examples at various stages of folliculogenesis are indicated: A, antral follicle; S, secondary follicle; P, primary/primordial follicle. Bar = 100 µm.