title: Microtubule-severing activity of the AAA+ ATPase Katanin is essential for female meiotic spindle assembly.
abstract: In most animals, female meiotic spindles are assembled in the absence of centrosomes. How microtubules (MTs) are organized into acentrosomal meiotic spindles is poorly understood. In Caenorhabditis elegans, assembly of female meiotic spindles requires MEI-1 and MEI-2, which constitute the microtubule-severing AAA+ ATPase Katanin. However, the role of MEI-2 is not known and whether MT severing is required for meiotic spindle assembly is unclear. Here, we show that the essential role of MEI-2 is to confer MT binding to Katanin, which in turn stimulates the ATPase activity of MEI-1, leading to MT severing. To test directly the contribution of MT severing to meiotic spindle assembly, we engineered Katanin variants that retained MT binding and MT bundling activities but that were inactive for MT severing. In vivo analysis of these variants showed disorganized microtubules that lacked focused spindle poles reminiscent of the Katanin loss-of-function phenotype, demonstrating that the MT-severing activity is essential for meiotic spindle assembly in C. elegans Overall, our results reveal the essential role of MEI-2 and provide the first direct evidence supporting an essential role of MT severing in meiotic spindle assembly in C. elegans.
authors: Institut Jacques Monod, Cell Cycle and Development Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France nicolas.joly@ijm.fr lionel.pintard@ijm.fr.
authors: Nicolas
authors: 0000-0003-2731-3827
authors: N
authors: Joly
authors: Institut Jacques Monod, Cell Cycle and Development Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France.
authors: Lisa
authors: L
authors: Martino
authors: Institut Jacques Monod, Cell Division and Reproduction Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France.
authors: Emmanuelle
authors: E
authors: Gigant
authors: Institut Jacques Monod, Cell Division and Reproduction Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France.
authors: Julien
authors: J
authors: Dumont
authors: Institut Jacques Monod, Cell Cycle and Development Team, Centre National de la Recherche Scientifique and University of Paris Diderot and Sorbonne Paris Cité UMR7592, Paris 75013, France nicolas.joly@ijm.fr lionel.pintard@ijm.fr.
authors: Lionel
authors: L
authors: Pintard
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D000074201:Katanin; D008540:Meiosis / Q000235:genetics / Q000502:physiology; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D000251:Adenosine Triphosphatases; C086678:MEI-1 protein, C elegans; C409220:MEI-2 protein, C elegans; D000074201:Katanin
keywords: AAA+ ATPase; C. elegans; MEI-1; MEI-2; Meiosis; Microtubule severing