The response to errors requires the kinetochore, but not components of the SAC. (A) Mid anaphase spindles stained for DNA (blue), tubulin (green, columns 1 and 6), KNL-3 (green, column 5), and AIR-2 (red). Neither knl-1(RNAi) nor knl-3(RNAi) causes a ring disassembly delay. At 30°C, AIR-2 does not remain in rings after partial depletion of KNL-1 and KNL-3. Images were not restricted to the mid anaphase cutoff of ≥2.5 µm to illustrate that AIR-2 relocalizes in early anaphase as well. (B) Mid anaphase spindles stained for DNA (blue), tubulin (green), AIR-2 (red), and MDF-1. AIR-2 remains in rings after 30°C treatment in worms depleted of MDF-1, SAN-1, and MDF-1/SAN-1 and in bub-3 and san-1 mutant strains. (C) Quantification of mid anaphase spindles with AIR-2 in rings for the kinetochore and SAC depletions at 15°C and 30°C. Includes MI and MII spindles with chromosome distances ≥2.5 µm. Note that depletion of SAC components alone (15°C) increased the percentage of spindles with AIR-2 in rings. In the case of MDF-1, this percentage did not increase significantly when combined with a 30°C treatment, suggesting that although MDF-1 does not appear to be absolutely required for an error response, its depletion may affect the magnitude of the response. Bars, 2.5 µm.