1. Dual roles of Incenp crucial to the assembly of the acentrosomal metaphase spindle in female meiosis.
- Author
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Colombié N, Cullen CF, Brittle AL, Jang JK, Earnshaw WC, Carmena M, McKim K, and Ohkura H
- Subjects
- Animals, Animals, Genetically Modified, Centrosome physiology, Chromosomal Proteins, Non-Histone genetics, Drosophila genetics, Drosophila Proteins genetics, Female, Genes, Insect, Kinesins physiology, Meiosis genetics, Metaphase genetics, Metaphase physiology, Microtubules physiology, Mutation, Chromosomal Proteins, Non-Histone physiology, Drosophila cytology, Drosophila physiology, Drosophila Proteins physiology, Meiosis physiology
- Abstract
Spindle formation in female meiosis differs from mitosis in many animals, as it takes place independently of centrosomes, and the molecular requirements of this pathway remain to be understood. Here, we report two crucial roles of Incenp, an essential subunit of the chromosomal passenger complex (the Aurora B complex), in centrosome-independent spindle formation in Drosophila female meiosis. First, the initial assembly of spindle microtubules is drastically delayed in an incenp mutant. This clearly demonstrates, for the first time, a crucial role for Incenp in chromosome-driven spindle microtubule assembly in living oocytes. Additionally, Incenp is necessary to stabilise the equatorial region of the metaphase I spindle, in contrast to mitosis, where the equivalent function becomes prominent after anaphase onset. Our analysis suggests that Subito, a kinesin-6 protein, cooperates with Incenp for this latter function, but not in microtubule assembly. We propose that the two functions of Incenp are part of the mechanisms that compensate for the lack of centrosomes during meiotic spindle formation.
- Published
- 2008
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