MIC behavior under various conditions. (a) In the spo11Δ mutant, MIC elongation arrests at a spindle-shaped stage, but treatment with cisplatin (CP), ionizing radiation (IR), UV, or MMS restores full elongation (crescent). (b) MIC shapes 3.5 h after induction of meiosis. Relative frequencies of round and egg-shaped (stage I-II), spindle-shaped (stage III), and full-crescent (stage IV) MICs are shown. Although in the untreated spo11Δ strain MICs arrest early in elongation and the frequency of fully elongated, crescent-shaped stage IV MICs is zero, treatment with cisplatin (CP), ionizing radiation (IR), UV, or MMS restores this class of nuclei to almost wild-type levels. The sample size n of nuclei scored in each experiment is given in brackets. (c) In the wild type (WT), meiotic MICs change their shape from spindle-shaped to full-crescent. However, elongation is suppressed by treatment with the kinase inhibitors caffeine or wortmannin or with the microtubule inhibitor benomyl. (a and c) DAPI staining. Bar, (a and c) 10 μm.