Merotelic attachment leads to abortive anaphase when interdigitated MTs are defective. (A, top) Image series of a rad21-K1 ase1Δ ndc80-gfp cdc11-cfp cell during mitosis showing two lagging Kts (one of them stretched; white arrow). (bottom) Kymograph showing a rapid collapse of the spindle. A schematic representation of a fission yeast cell shape is shown (dashed oval). (B, left) Image series of ase1Δ atb2-gfp (MTs) ndc80-gfp (Kts) during mitosis. (right) Image series of rad21-K1 ase1Δ SV40-gfp-atb2 (MTs) ndc80-gfp (Kts) cell during mitosis in the presence of a merotelic attachment (red arrows).