A kinetochore-independent mechanism drives anaphase chromosome separation during acentrosomal meiosis
- 22 August 2010
- journal article
- research article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 12 (9), 894-901
- https://doi.org/10.1038/ncb2093
Abstract
How acentrosomal meiotic spindles separate chromosomes in anaphase has been unclear. Although kinetochores are required for the bi-orientation of chromosomes, chromosome separation may instead be driven by CLASP/CLS-2 mediated microtubule assembly. Although assembly of acentrosomal meiotic spindles has been extensively studied1, little is known about the segregation of chromosomes on these spindles. Here, we show in Caenorhabditis elegans oocytes that the kinetochore protein, KNL-1, directs assembly of meiotic kinetochores that orient chromosomes. However, in contrast to mitosis, chromosome separation during meiotic anaphase is kinetochore-independent. Before anaphase, meiotic kinetochores and spindle poles disassemble along with the microtubules on the poleward side of chromosomes. During anaphase, microtubules then form between the separating chromosomes. Functional analysis implicated a set of proteins that localize to a ring-shaped domain between kinetochores during pre-anaphase spindle assembly and anaphase separation. These proteins are localized by the chromosomal passenger complex, which regulates the loss of meiotic chromosome cohesion2,3,4. Thus, meiotic segregation in C. elegans is a two-stage process, where kinetochores orient chromosomes, but are then dispensable for their separation. We suggest that separation is controlled by a meiosis-specific chromosomal domain to coordinate cohesin removal and chromosome segregation.Keywords
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