Effects of mre11, sae2, exo1 and rad51 on MMS-induced mono- and diubiquitination of PCNA.

Overnight cultures were subcultured and allowed to grow to a cell count of approximately 1×107cells/ml before being treated with 0.05% MMS (as indicated) for 90 minutes. Total cell extracts were obtained under denaturing conditions and analyzed by SDS-PAGE and western blot. Strains used were HK578-10A (wild type) and its isogenic derivatives WXY994 (pol30-K164R), WXY2959 (siz1Δ), WXY2995 (mre11Δ siz1Δ), WXY2962 (sae2Δ siz1Δ), WXY2963 (exo1Δ siz1Δ) and WXY2994 (rad51Δ siz1Δ). Ub1 refers to monoubiquitinated PCNA. Ub2 refers to diubiquitinated PCNA.