Figure 1: DNA damage induction and repair in GV oocytes.
From: DNA damage induces a meiotic arrest in mouse oocytes mediated by the spindle assembly checkpoint
(a) Representative γH2AX immunofluorescence in a GV oocyte following either no treatment (control), or etoposide (25 μg ml−1). γH2AX staining is negligible in the control oocyte but visible in the nucleus following DNA damage. Scale bar, 5 μm. (b) Nuclear γH2AX immunofluorescence levels in individual oocytes following etopiside (25 μg ml−1), bleomycin (1 μM), ultraviolet B (UVB, 300 nm, 30 s) or ionizing radiation (IR, 4.5 Gy). Data are pooled from three mice for each condition. (c) Nuclear γH2AX accumulation in oocytes at various times after etoposide (25 μg ml−1) exposure. Oocytes were maintained in GV arrest for the times indicated after 15-min exposure to etoposide or vehicle (0.1% DMSO). Nuclear γH2AX accumulation following etoposide exposure is initially high, but drops to control levels over 10 h. Oocytes were pooled from four mice. (a–c) Oocytes were fixed at either 15 min (etoposide and bleomycin) or 40 min after treatment. (b,c) Each data point represents one oocyte; means and s.d. are represented by the horizontal lines; *P<0.05, compared with control; **P<0.001, ***P<0.0001 (ANOVA, Tukey’s post hoc test).
