Gamma-tubulin is required for the structure and function of the microtubule organizing centre in Drosophila neuroblasts.

Sunkel, Cláudio E.; Gomes, Rui; Sampaio, Paula; Perdigão, Joana; González, Cayetano

doi:10.1002/j.1460-2075.1995.tb06972.x

Cited by 171 publications

(134 citation statements)

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“…Cells of g-tubulin mutants isolated in animal, fungus, and yeast exhibit aberrant microtubule organization (Oakley et al, 1990;Horio et al, 1991;Sobel and Snyder, 1995;Sunkel et al, 1995). Defects in nuclear division observed during tubg1-1 tubg2-1 gametogenesis are consistent with abnormalities in microtubule nucleation and organization.…”

Section: Microtubule Defects During Mutant Pollen Developmentmentioning

confidence: 99%

γ-Tubulin Is Essential for Microtubule Organization and Development inArabidopsis

et al. 2006

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The process of microtubule nucleation in plant cells is still a major question in plant cell biology. g-Tubulin is known as one of the key molecular players for microtubule nucleation in animal and fungal cells. Here, we provide genetic evidence that in Arabidopsis thaliana, g-tubulin is required for the formation of spindle, phragmoplast, and cortical microtubule arrays. We used a reverse genetics approach to investigate the role of the two Arabidopsis g-tubulin genes in plant development and in the formation of microtubule arrays. Isolation of mutants in each gene and analysis of two combinations of g-tubulin double mutants showed that the two genes have redundant functions. The first combination is lethal at the gametophytic stage. Disruption of both g-tubulin genes causes aberrant spindle and phragmoplast structures and alters nuclear division in gametophytes. The second combination of g-tubulin alleles affects late seedling development, ultimately leading to lethality 3 weeks after germination. This partially viable mutant combination enabled us to follow dynamically the effects of g-tubulin depletion on microtubule arrays in dividing cells using a green fluorescent protein marker. These results establish the central role of g-tubulin in the formation and organization of microtubule arrays in Arabidopsis.

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Section: Microtubule Defects During Mutant Pollen Developmentmentioning

confidence: 99%

γ-Tubulin Is Essential for Microtubule Organization and Development inArabidopsis

et al. 2006

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“…We counterstained spermatids with GFPpericentrin-AKAP450 centrosomal targeting (PACT; a centriole-targeting domain found in D-PLP; Gillingham and Munro, 2000;Martinez-Campos et al, 2004) to label basal bodies and found that Bld10 localized to the rod-shaped basal body, which is surrounded by the centriolar adjunct (Tates, 1971), a collar-like PCM structure that contains ␥-tubulin (Figure 2, C and D; Sunkel et al, 1995;Wilson et al, 1997). Bld10 was concentrated at the proximal and distal ends of the basal body, with lower expression at the region encircled by the centriolar adjunct ( Figure 2, C and D).…”

Section: Bld10 Is a Centriolar And Sperm Basal Body Proteinmentioning

confidence: 99%

DrosophilaBld10 Is a Centriolar Protein That Regulates Centriole, Basal Body, and Motile Cilium Assembly

Mottier-Pavie

Megraw

2009

MBoC

107

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Cilia and flagella play multiple essential roles in animal development and cell physiology. Defective cilium assembly or motility represents the etiological basis for a growing number of human diseases. Therefore, how cilia and flagella assemble and the processes that drive motility are essential for understanding these diseases. Here we show that Drosophila Bld10, the ortholog of Chlamydomonas reinhardtii Bld10p and human Cep135, is a ubiquitous centriolar protein that also localizes to the spermatid basal body. Mutants that lack Bld10 assemble centrioles and form functional centrosomes, but centrioles and spermatid basal bodies are short in length. bld10 mutant flies are viable but male sterile, producing immotile sperm whose axonemes are deficient in the central pair of microtubules. These results show that Drosophila Bld10 is required for centriole and axoneme assembly to confer cilium motility. INTRODUCTIONCentrioles lie at the core of centrosomes. They consist of a ninefold symmetrical array of nine triplet microtubules arranged in a cylinder. In most differentiated cell types, centrioles transform into basal bodies, membrane-embedded centrioles that template cilium and flagellum axoneme assembly. The requirement of cilia and flagella for many developmental and physiological processes, together with the growing list of human diseases that result from defects in basal bodies and cilia (Badano et al., 2006;Bisgrove and Yost, 2006;Bettencourt-Dias and Glover, 2007;Fliegauf et al., 2007;Marshall, 2008), drives the need to understand the basic processes involved in centriole, basal body, cilium assembly, and motility.In Drosophila several approaches have identified evolutionarily conserved centriole proteins required for centriole biogenesis including Sak, Sas4, Sas6, Ana1, Ana2, and Asterless (Bettencourt-Dias et al., 2005;Basto et al., 2006;Goshima et al., 2007;Rodrigues-Martins et al., 2007;Blachon et al., 2008). In flies, mutations in these genes abolish centrosome and cilium/flagellum assembly (except mutations in ana1 and ana2, which have not been described yet). Additional centriole/ basal body proteins including Spd-2, Drosophila pericentrin-like protein (D-PLP)/CP309, and uncoordinated (UNC) function in pericentriolar material (PCM) recruitment to centrosomes and/or the assembly of cilia and flagella Kawaguchi and Zheng, 2004;Martinez-Campos et al., 2004;Dix and Raff, 2007;Giansanti et al., 2008). Identification of the complete set of centriole components is necessary to define their individual and cooperative roles in the assembly and function of centrioles and cilia.In Chlamydomonas reinhardtii, mutations in the bld10 gene result in complete loss of flagella, giving the cells a "bald" appearance, due to a failure to assemble centrioles (Matsuura et al., 2004;Hiraki et al., 2007). Bld10p functions in the formation of the cartwheel, a ninefold symmetrical scaffold structure essential for an early step of centriole/basal body assembly . From RNA interference (RNAi) studies in cell culture, the human ort...

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“…Under these conditions, centrosomes in Caenorhabditis elegans and Drosophila embryos were compromised in their ability to form mitotic asters (Hannak et al, 2002;Strome et al, 2001), separate from one another (Barbosa et al, 2003;Sampaio et al, 2001), and organize meiotic and mitotic spindles (Sunkel et al, 1995;Barbosa et al, 2000Barbosa et al, , 2003. It is of interest that mitotic asters in some of these systems formed in the absence of ␥ tubulin or other ␥ tubulin ring complex proteins (Strome et al, 2001;Hannak et al, 2002;Barbosa et al, 2003).…”

Section: Centrosomal Anchoring Of ␥ Turcs By Pericentrin Is Required mentioning

confidence: 99%

Mitosis-specific Anchoring of γ Tubulin Complexes by Pericentrin Controls Spindle Organization and Mitotic Entry

Zimmerman

Sillibourne

Rosa

et al. 2004

MBoC

275

258

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Microtubule nucleation is the best known function of centrosomes. Centrosomal microtubule nucleation is mediated primarily by ␥ tubulin ring complexes (␥ TuRCs). However, little is known about the molecules that anchor these complexes to centrosomes. In this study, we show that the centrosomal coiled-coil protein pericentrin anchors ␥ TuRCs at spindle poles through an interaction with ␥ tubulin complex proteins 2 and 3 (GCP2/3). Pericentrin silencing by small interfering RNAs in somatic cells disrupted ␥ tubulin localization and spindle organization in mitosis but had no effect on ␥ tubulin localization or microtubule organization in interphase cells. Similarly, overexpression of the GCP2/3 binding domain of pericentrin disrupted the endogenous pericentrin-␥ TuRC interaction and perturbed astral microtubules and spindle bipolarity. When added to Xenopus mitotic extracts, this domain uncoupled ␥ TuRCs from centrosomes, inhibited microtubule aster assembly, and induced rapid disassembly of preassembled asters. All phenotypes were significantly reduced in a pericentrin mutant with diminished GCP2/3 binding and were specific for mitotic centrosomal asters as we observed little effect on interphase asters or on asters assembled by the Ran-mediated centrosome-independent pathway. Additionally, pericentrin silencing or overexpression induced G2/antephase arrest followed by apoptosis in many but not all cell types. We conclude that pericentrin anchoring of ␥ tubulin complexes at centrosomes in mitotic cells is required for proper spindle organization and that loss of this anchoring mechanism elicits a checkpoint response that prevents mitotic entry and triggers apoptotic cell death. INTRODUCTIONThe centrosome is the primary microtubule-organizing center in animal cells. At the centrosome core is a pair of barrel-shaped microtubule assemblies, the centrioles (Doxsey, 2001). Centrioles are capable of self-assembly (Marshall et al., 2001;Khodjakov et al., 2002) and can serve as templates for recruitment and organization of the surrounding pericentriolar matrix (Bobinnec et al., 1998;Kirkham et al., 2003). The pericentriolar material or centrosome matrix contains a high proportion of coiled coil proteins and is the site of microtubule nucleation. Within the matrix are large protein complexes of ␥ tubulin and associated proteins that have a ring-like structure and mediate the nucleation of microtubules called ␥ tubulin ring complexes or ␥ TuRCs (Moritz et al., 1995a;Zheng et al., 1995). Other proteins may share the ability to nucleate microtubules because centrosomes can organize microtubules in the absence of functional ␥ tubulin (Sampaio et al., 2001;Strome et al., 2001;Hannak et al., 2002).During cell cycle progression, centrosomes "mature" by recruiting additional ␥ TuRCs and several other proteins, resulting in an increase in the nucleation capacity of the centrosome (reviewed in Blagden and Glover, 2003). However, we still know very little about proteins that directly anchor ␥ TuRCs to centrosomes in vertebrate cells. ...

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Gamma-tubulin is required for the structure and function of the microtubule organizing centre in Drosophila neuroblasts.

Cited by 171 publications

References 20 publications

γ-Tubulin Is Essential for Microtubule Organization and Development inArabidopsis

γ-Tubulin Is Essential for Microtubule Organization and Development inArabidopsis

DrosophilaBld10 Is a Centriolar Protein That Regulates Centriole, Basal Body, and Motile Cilium Assembly

Mitosis-specific Anchoring of γ Tubulin Complexes by Pericentrin Controls Spindle Organization and Mitotic Entry

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