Figure 2.

Hira Is Essential for Progression through Oogenesis and Acquisition of Developmental Competence

(A) Number of ovulated oocytes recovered per female after hormonal stimulation. Numbers of females scored are indicated in the columns. Error bars indicate SEM. ^∗∗∗p < 0.001; statistical analysis was carried out using two-tailed unpaired Student’s t test.

(B) Ovaries of Hira^f/f, Hira^f/fGdf9-Cre⁺, and Hira^f/fZp3-Cre⁺ females were collected from mice born on the same date and ovarian images were taken in a single picture.

(C) Representative images show H&E staining of 3-week (top) and 6-week (bottom) ovarian sections (follicles indicated by arrows).

(D) Maternal Hira depletion results in defects in chromosome condensation and segregation. Representative bright-field images of MII oocytes recovered from two Hira^f/f and two Hira^f/fGdf9-Cre⁺ mice at 3 weeks of age are shown. Arrows (left) indicate oocytes with defective asymmetric division normally associated with first polar body extrusion (left). The oocytes were fixed and stained with DAPI (right). Arrows and arrowheads (right) indicate chromosome bridges and lagging chromosomes, respectively. Quantification of normal and abnormal MII oocytes is shown (bottom right).

(E) Early developmental arrest of parthenogenetic embryos with maternal Hira depletion. Representative images show embryos (left); quantification of developmental progression is shown (right). Oocytes lacking Hira do not progress beyond the two-cell stage. Embryo numbers are indicated above each column. Error bars indicate SEM. See also Figures S2, S3, and S4.