Pachytene checkpoint activation persists in mer3Δ and spo22Δ, and, to a lesser degree, in the mer1Δ strain. (A) Western blot measuring phosphorylation state of CDK on Y19 in wild-type (WT), mer1Δ, mer2Δ, mer3Δ, spo22Δ, and spo70Δ strains 2 h and 9 h after induction of meiosis. (B) Same as A using mer3Δmer1Δ, mer3Δmer2Δ, spo22Δmer1Δ, and spo22Δmer2Δ strains. Nap1p was used as a loading control in A and B. (C) Sample pictures of major phenotypes of mer3Δ, mer3Δmer1Δ, and mer3Δmer2Δ strains at 9 h after induction of meiosis. On the left are differential interference contrast micrographs, and on the right are superimposed fluorescence micrographs of DNA stained with DAPI (blue) and CenV-GFP (green). Bar, 2 μm.