"We first examined whether kinetochore resolution is complete by prometaphase in
air-2(
or207ts) mutant embryos. Using antibodies directed against two additional kinetochore antigens, HCP-4 and MCAK, we found that at prometaphse, i.e., after NEBD but prior to capture of all kinetochores by microtubules, two threads of kinetochore antigens are found flanking each pair of sister chromatids (15/15 embryos) (Figure 4B). During metaphase, however, these kinetochore markers revealed that chromatids fail to align properly to form an ordered metaphase plate (Figure 4B) (8/8 embryos)."