Figure 6: MI arrest following DNA damage is independent of bivalent biorientation.
From: DNA damage induces a meiotic arrest in mouse oocytes mediated by the spindle assembly checkpoint
(a) Percentage of oocytes that undergo PBE or MI arrest following GV-stage treatment with ultraviolet B (15 s), etoposide (25 μg ml−1, 15 min), or a low dose of nocodazole (25 nM) added for the duration of MI. (b–d) Bivalent tension (stretch), displacement from the metaphase plate (displacement) and bivalent orientation (θ); in oocytes treated throughout MI with nocodazole (b) or before NEB for 15 s with ultraviolet B (c) or 15 min with etoposide (d). Data points are individual bivalents combined from three oocytes per treatment group at 8 h. The maximum number of s.d.’s from the 8 h PBE group mean on any axis is used to colour the bivalent. The three nocodazole-treated oocytes all underwent anaphase in the next 10 min. (e–g) Bivalent stretch (e) displacement (e) and orientation (f) from untreated oocytes and those in (b–d). Each group assessed 3 oocytes and 60 bivalents. Bars indicate means, and errors are s.d. Background colouring represents multiple s.d.’s from the mean in the control group. *, indicates significant difference from control, P<0.05, ANOVA with Tukey’s post hoc test.
