Fig. 4.

Depletion of Scc3 causes meiotic arrest with unrepaired DSBs. a Scc3 RNAi was induced in growing cells for 24 h to fully deplete the protein. Vegetative cell shows a mitotic division with lagging chromosomes (arrow). A WT mitotic cell in anaphase is shown for reference. Starved scc3i cells were mated with WT cells. Prophase occurs normally for both cells, then the scc3i partner (top cell) arrests in a metaphase-like state, while the WT partner (bottom cell) completes meiotic divisions. b DSBs persist in scc3i cells. Mating cells were fixed in high detergent and stained for Dmc1/Rad51 (left) or by modified Schaudinn’s fixation and stained for γ-H2A.X (right). Dmc1/Rad51 and γ-H2A.X foci are markers for unrepaired DSBs. In the WT partner, DSBs are only detected in prophase stages of meiosis. However, the scc3i cells mated with WT cells show persistent Dmc1/Rad51 and γ-H2A.X foci in the arrested scc3i cells at metaphase (arrows in top cells). Scale bars: 5 μm