Kinetochore Localization of BUB-1 is required to promote anaphase onset. (A) Images from a time-lapse sequence of a one-cell embryo expressing mCh::H2b and GFP::BUB-1. Time is given in seconds after NEBD. Bar, 5 µm. (B) Schematic of features of the KNL-1 N terminus. The deletions analyzed are depicted below. (C) Representative images of BUB-1::GFP localization in the presence of indicated knl-1 transgenes, after depletion of endogenous KNL-1. Bars, 2 µm. (D) Immunoblots of BUB-1, KNL-1, and α-tubulin, which serves as a loading control, for the indicated conditions. As part of the antigen used to generate the KNL-1 antibody (aa 8–256; Desai et al., 2003) is deleted in the Δ85–505 mutant, the band intensities of WT and Δ85–505 KNL-1 cannot be compared. (E) Plot of mean NEBD–anaphase onset intervals for the indicated conditions in one-cell embryos. Error bars indicate SD; red broken line is the control value; n is the number of embryos. (F) Plot of the mean delay in anaphase onset for the indicated conditions, generated by subtracting matched mean control values and propagating errors. Error bars indicate the 95% CI. KNL-1 mutants and their matched control (WT) values are from D; bub-1(RNAi), bub-3Δ and their matched control values are from Fig. 1 C.