Evidence for anaphase pulling forces during C. elegans meiosis

Abstract

Meiotic anaphase has been reported to be mediated by kinetochore-independent pushing forces in C. elegans. Danlasky et al. find that depletion of kinetochore proteins reduces pulling forces and prevents successful separation of homologous chromosomes during C. elegans meiosis.

Abstract

Anaphase chromosome movement is thought to be mediated by pulling forces generated by end-on attachment of microtubules to the outer face of kinetochores. However, it has been suggested that during C. elegans female meiosis, anaphase is mediated by a kinetochore-independent pushing mechanism with microtubules only attached to the inner face of segregating chromosomes. We found that the kinetochore proteins KNL-1 and KNL-3 are required for preanaphase chromosome stretching, suggesting a role in pulling forces. In the absence of KNL-1,3, pairs of homologous chromosomes did not separate and did not move toward a spindle pole. Instead, each homolog pair moved together with the same spindle pole during anaphase B spindle elongation. Two masses of chromatin thus ended up at opposite spindle poles, giving the appearance of successful anaphase.