title: The relative roles of centrosomal and kinetochore-driven microtubules in Drosophila spindle formation.
abstract: Mitotic spindle assembly in centrosome-containing cells relies on two main microtubule (MT) nucleation pathways, one based on centrosomes and the other on chromosomes. However, the relative role of these pathways is not well defined. Here we review the studies on spindle formation in Drosophila centrosome-containing cells. Mutants with impaired centrosome function assemble functional anastral spindles in somatic tissues and survive to adulthood. In contrast, mutants defective in chromosome-driven MT formation form highly aberrant mitotic spindles and die at larval stages. The requirements for spindle assembly in Drosophila male meiotic cells are diametrically opposed to those of somatic cells. Spermatocytes assemble morphologically normal spindles in the complete absence of chromosome-induced MTs, but are unable to organize a functional spindle in the absence of centrosomal MTs. Male meiotic spindles are much larger than mitotic spindles as they contain most of the tubulin needed for sperm tail formation. We suggest that the centrosome-based mechanism of spindle assembly in spermatocytes reflects their need for rapid and efficient polymerization of a particularly large amount of tubulin.
authors.affiliation: Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy. maurizio.gatti@uniroma1.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gatti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bucciarelli
authors.forename: Ramona
authors.initials: R
authors.lastname: Lattao
authors.forename: Claudia
authors.initials: C
authors.lastname: Pellacani
authors.forename: Violaine
authors.initials: V
authors.lastname: Mottier-Pavie
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Giansanti
authors.forename: Maria Patrizia
authors.initials: MP
authors.lastname: Somma
authors.forename: Silvia
authors.initials: S
authors.lastname: Bonaccorsi
mesh_terms: D000818:Animals; D018385:Centrosome / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D008870:Microtubules / Q000378:metabolism / Q000502:physiology*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins