title: Drosophila SPD-2 is an essential centriole component required for PCM recruitment and astral-microtubule nucleation.
abstract: SPD-2 is a C. elegans centriolar protein required for both centriole duplication and pericentriolar material (PCM) recruitment [1-4]. SPD-2 is conserved in Drosophila (DSpd-2) and is a component of the fly centriole [5-7]. The analysis of a P element-induced hypomorphic mutation has shown that DSpd-2 is primarily required for PCM recruitment at the sperm centriole but is dispensable for both centriole duplication and aster formation [5]. Here we show that null mutations carrying early stop codons in the DSpd-2 coding sequence suppress astral microtubule (MT) nucleation in both neuroblasts (NBs) and spermatocytes. These mutations also disrupt proper Miranda localization in dividing NBs, as previously observed in mutants lacking astral MTs [8-10]. Spermatocyte analysis revealed that DSpd-2 is enriched at both the centrioles and the PCM and is required for the maintenance of cohesion between the two centrioles but not for centriole duplication. We found that DSpd-2 localization at the centrosome requires the wild-type activity of Asl but is independent of the function of D-PLP, Cnn, gamma-tubulin, DGrip91, and D-TACC. Conversely, DSpd-2 mutants displayed normal centrosomal accumulations of Asl and D-PLP, strongly reduced amounts of Cnn, gamma-tubulin, and DGrip91, and diffuse localization of D-TACC. These results indicate that DSpd-2 functions in a very early step of the PCM recruitment pathway.
authors.affiliation: Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Giansanti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bucciarelli
authors.forename: Silvia
authors.initials: S
authors.lastname: Bonaccorsi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gatti
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002502:Centrioles / Q000378:metabolism*; D004330:Drosophila / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000166:cytology / Q000378:metabolism; D008297:Male; D008870:Microtubules / Q000378:metabolism*; D013090:Spermatocytes / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism; D003598:Cytoskeletal Proteins
chemical_list: D029721:Drosophila Proteins; C529373:SPD-2 protein, Drosophila; D003598:Cytoskeletal Proteins