Key players in chromosome segregation in Caenorhabditis elegans.

In contrast to many eukaryotic organisms in which kinetochores are assembled on localized centromeres of monocentric chromosomes, Caenorhabditis elegans has diffuse kinetochores, termed holo-kinetochores, which are assembled along the entire length of the mitotic chromosome. Despite this cytologically distinct chromosomal architecture, holo-kinetochores of C. elegans and kinetochores of other eukaryotes share structurally and functionally conserved properties. The amphitelic attachment of sister kinetochores to microtubules can be achieved by proper chromosomal organization, which relies on spatiotemporally orchestrated functions of conserved protein complexes such as the cohesin, condensin, and chromosomal passenger complexes during mitosis and meiosis in C. elegans. Moreover, the structure of spindle assembly checkpoint components and their safeguard function are also well conserved in C. elegans. Extensive efforts in the last few years to elucidate the molecular mechanisms of the C. elegans spindle assembly checkpoint have revealed its unique features. In this review, I will focus on the conservation and diversity of proteins that are required to maintain chromosome transmission fidelity during mitosis and meiosis in C. elegans.