A Switch in Microtubule Orientation during C. elegans Meiosis.

Autor:	Redemann S; Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. Electronic address: sz5j@virginia.edu., Lantzsch I; Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany., Lindow N; Zuse Institute Berlin, Berlin, Germany., Prohaska S; Zuse Institute Berlin, Berlin, Germany., Srayko M; Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada., Müller-Reichert T; Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. Electronic address: mueller-reichert@tu-dresden.de.
Jazyk:	angličtina
Zdroj:	Current biology : CB [Curr Biol] 2018 Sep 24; Vol. 28 (18), pp. 2991-2997.e2. Date of Electronic Publication: 2018 Sep 06.
DOI:	10.1016/j.cub.2018.07.012
Abstrakt:	In oocytes of many organisms, meiotic spindles form in the absence of centrosomes [1-5]. Such female meiotic spindles have a pointed appearance in metaphase with microtubules focused at acentrosomal spindle poles. At anaphase, the microtubules of acentrosomal spindles then transition to an inter-chromosomal array, while the spindle poles disappear. This transition is currently not understood. Previous studies have focused on this inter-chromosomal microtubule array and proposed a pushing model to drive chromosome segregation [6, 7]. This model includes an end-on orientation of microtubules with chromosomes. Alternatively, chromosomes were thought to associate along bundles of microtubules [8, 9]. Starting with metaphase, this second model proposed a pure lateral chromosome-to-microtubule association up to the final meiotic stages of anaphase. Here, we applied large-scale electron tomography [10] of staged C. elegans oocytes in meiosis to analyze the orientation of microtubules in respect to chromosomes. We show that microtubules at metaphase I are primarily oriented laterally to the chromosomes and that microtubules switch to an end-on orientation during progression through anaphase. We further show that this switch in microtubule orientation involves a kinesin-13 microtubule depolymerase, KLP-7, which removes laterally associated microtubules around chromosomes. From this, we conclude that both lateral and end-on modes of microtubule-to-chromosome orientations are successively used in C. elegans oocytes to segregate meiotic chromosomes. (Published by Elsevier Ltd.)
Databáze:	MEDLINE
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