Dis2 overexpression sensitises cells to DNA damage. (A) Wild-type cells transformed with vector or nmt1::dis2 plasmid were grown in the absence of thiamine for 16 h at 30°C and, together with checkpoint mutant strains rad3-136 and chk1Δ, serial dilutions were spotted onto minimal medium agar containing no drug, 0.013% MMS or 62 ng/ml 4-NQO. (B) DAPI-stained cells of strains grown as described in (A), and treated with 0.01% MMS for 16 h. (C) Wild-type cells transformed with vector (○) or nmt1::dis2 plasmid (•), together with chk1Δ (□) and rad3-136 (▵), were treated with the indicated doses of UV-C and ionising radiation, and per cent survival compared with unirradiated controls was determined. (D) Wild-type and t.s. mutant strains transformed with vector (○) or nmt1::dis2 (•), or crossed with chk1Δ (□), were grown in the absence of thiamine for 24 h at 25°C, then shifted to the restrictive temperature of 36°C, and the per cent of cells passing mitosis or with aberrant mitoses was followed over time.