Functional role of ε-tubulin in the assembly of the centriolar microtubule scaffold

Dupuis-Williams, Pascale; Fleury-Aubusson, Anne; Loubresse, N. Garreau de; Geoffroy, H; Vayssié, Laurence; Galvani, Angélique; Espigat, Aude; Rossier, Jean

doi:10.1083/jcb.200205028

Cited by 77 publications

(71 citation statements)

References 43 publications

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“…It has an important role in determining the orientation of spindle fibers, the symmetry of cell division and the organization of dividing cells and is a prerequisite for mitotic activity (Chang et al, 2003, Dupuis-Williams et al, 2002. This might be linked to our observation that proliferation of lens cells is severely impaired in ak lenses as shown by the BrdU incorporation assay (Fig.…”

Section: Discussionmentioning

confidence: 68%

Pitx3 directly regulates Foxe3 during early lens development

Ahmad¹,

Aslam²,

Muenster³

et al. 2013

Int. J. Dev. Biol.

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Pitx3 is a bicoid-related homeodomain transcription factor critical for the development of the ocular lens, mesencephalic dopaminergic neurons and skeletal muscle. In humans, mutations in PITX3 are responsible for cataracts and anterior segment abnormalities of varying degree; polymorphisms are associated with Parkinson's disease. In aphakia (ak) mice, two deletions in the promoter region of Pitx3 cause abnormal lens development. Here, we investigated systematically the role of Pitx3 in lens development including its molecular targets responsible for the ak phenotype. We have shown that ak lenses exhibit reduced proliferation and aberrant fiber cell differentiation. This was associated with loss of Foxe3 expression, complete absence of Prox1 expression, reduced expression of e-tubulin and earlier expression of g-crystallin during lens development. Using EMSA and ChIP assays, we demonstrated that Pitx3 binds to an evolutionary conserved bicoid-binding site on the 5'-upstream region of Foxe3. Finally, Pitx3 binding to 5'-upstream region of Foxe3 increased transcriptional activity significantly in a cell-based reporter assay. Identification of Foxe3 as a transcriptional target of Pitx3 explains at least in part some of the phenotypic similarities of the ak and dyl mice (dysgenic lens, a Foxe3 allele). These findings enhance our understanding of the molecular cascades which subserve lens development.

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Section: Discussionmentioning

confidence: 68%

Pitx3 directly regulates Foxe3 during early lens development

Ahmad¹,

Aslam²,

Muenster³

et al. 2013

Int. J. Dev. Biol.

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“…A mutant isolated in Chlamydomonas resulted in singlet, rather than triplet, microtubules in the basal body, and supplied the first indication that e-tubulin is important for proper triplet microtubule assembly and/or maintenance (Dutcher et al, 2002). A subsequent study in Paramecium used RNAi to deplete e-tubulin and reported degradation of the microtubule triplets, reaffirming its importance at the basal body (Dupuis- Williams et al, 2002). Thus far, studies have not clearly distinguished between a role in basal body assembly as opposed to maintenance, nor have they determined how e-tubulin might carry out these functions.…”

Section: Introductionmentioning

confidence: 89%

“…It was found to localize to centrosomes and be essential for centriole duplication in Xenopus extracts (Chang et al, 2003;Chang and Stearns, 2000). Work in Chlamydomonas reinhardtii and Paramecium terauralia identified e-tubulin as an essential component of basal bodies (Dupuis-Williams et al, 2002;Dutcher et al, 2002). A mutant isolated in Chlamydomonas resulted in singlet, rather than triplet, microtubules in the basal body, and supplied the first indication that e-tubulin is important for proper triplet microtubule assembly and/or maintenance (Dutcher et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Currently, c-tubulin is known to nucleate microtubules at the (2)-end and is present at the two major microtubule organizing centers (MTOCs): centrosomes and basal bodies (Wiese and Zheng, 2000). Much less is known about the function of e-and d-tubulin, but it appears that they are organelle specific and localize solely to centrosomes and basal bodies (Chang et al, 2003;Chang and Stearns, 2000;Dupuis-Williams et al, 2002;Dutcher et al, 2002;Dutcher and Trabuco, 1998).…”

Section: Introductionmentioning

confidence: 99%

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ε-tubulin is essential in Tetrahymena thermophila for the assembly and stability of basal bodies

Ross¹,

Clarissa²,

Giddings³

et al. 2013

Journal of Cell Science

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SummaryBasal bodies and centrioles are conserved microtubule-based organelles the improper assembly of which leads to a number of diseases, including ciliopathies and cancer. Tubulin family members are conserved components of these structures that are integral to their proper formation and function. We have identified the e-tubulin gene in Tetrahymena thermophila and detected the protein, through fluorescence of a tagged allele, to basal bodies. Immunoelectron microscopy has shown that e-tubulin localizes primarily to the core microtubule scaffold. A complete genomic knockout of e-tubulin has revealed that it is an essential gene required for the assembly and maintenance of the triplet microtubule blades of basal bodies. We have conducted site-directed mutagenesis of the e-tubulin gene and shown that residues within the nucleotide-binding domain, longitudinal interacting domains, and C-terminal tail are required for proper function. A single amino acid change of Thr150, a conserved residue in the nucleotide-binding domain, to Val is a conditional mutation that results in defects in the spatial and temporal assembly of basal bodies as well as their stability. We have genetically separated functions for the domains of e-tubulin and identified a novel role for the nucleotide-binding domain in the regulation of basal body assembly and stability.

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“…Gamma tubulin is also ubiquitous and likely emerged early, to function as a nucleating site that helps determine microtubule polarity and distribution. Additional tubulin isoforms delta and epsilon are ubiquitous among organisms with triplet microtubules, and the formation of triplet microtubules, essential for the function of basal bodies, has been shown to require both delta and epsilon tubulin in Chlamydomonas 25,26 and both epsilon 27 and the less ubiquitous eta tubulin 28 in Paramecium. The presence of these tubulin isoforms in members of both the unikont and bikont clades 17,29 argues for their evolution prior to the divergence of eukaryotes.…”

Section: Evolution Of Tubulin Dynein and Kinesinmentioning

confidence: 99%

The Evolution of Eukaryotic Cilia and Flagella as Motile and Sensory Organelles

Mitchell

Advances in Experimental Medicine and Biology

187

152

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Eukaryotic cilia and flagella are motile organelles built on a scaffold of doublet microtubules and powered by dynein ATPase motors. Some thirty years ago, two competing views were presented to explain how the complex machinery of these motile organelles had evolved. Overwhelming evidence now refutes the hypothesis that they are the modified remnants of symbiotic spirochaetelike prokaryotes, and supports the hypothesis that they arose from a simpler cytoplasmic microtubule-based intracellular transport system. However, because intermediate stages in flagellar evolution have not been found in living eukaryotes, a clear understanding of their early evolution has been elusive. Recent progress in understanding phylogenetic relationships among present day eukaryotes and in sequence analysis of flagellar proteins have begun to provide a clearer picture of the origins of doublet and triplet microtubules, flagellar dynein motors, and the 9+2 microtubule architecture common to these organelles. We summarize evidence that the last common ancestor of all eukaryotic organisms possessed a 9+2 flagellum that was used for gliding motility along surfaces, beating motility to generate fluid flow, and localized distribution of sensory receptors, and trace possible earlier stages in the evolution of these characteristics. Keywordscilia; flagella; motility; axoneme; microtubule; dynein; intraflagellar transport; central pair; radial spoke; tubulin Evidence for the presence of a 9+2, motile, sensory organelle in the last common eukaryotic ancestor As summarized in Figure 1, typical cilia and flagella (hereafter called flagella, there being no consistent structural or functional difference between organelles with these two designations) are motile projections oriented perpendicular to the cell surface, but they vary in length, in number per cell, and in the patterns of motility that they produce. They are composed of a cylinder (the axoneme) of nine doublet microtubules surrounding two single microtubules and are covered by the cell membrane. Between each pair of flagellar doublets are rows of axonemal dynein ATPases, which power the bending of these organelles, and extending toward the center of the cylinder are radial spokes, which touch upon a central apparatus and regulate axonemal dyneins. This central element consists of two single microtubules, assembled from a unique nucleating site 1 , plus many interconnecting microtubule-associated proteins (reviewed in ref.2). Together they form a structure that provides a cylindrical surface apposing the ends of the radial spokes 3 . mitcheld@upstate.edu, NIH Public Access The nine doublets assemble from a much shorter cylinder of nine triplet microtubules, the basal body or centriole, which is anchored to the cell surface and stabilized in the cytoplasm by other cytoskeletal elements. Basal bodies that anchor flagella are often interchangeable during the cell cycle with centrioles 4 , and these two names should be considered as two functional descriptions for the same structure....

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Functional role of ε-tubulin in the assembly of the centriolar microtubule scaffold

Cited by 77 publications

References 43 publications

Pitx3 directly regulates Foxe3 during early lens development

Pitx3 directly regulates Foxe3 during early lens development

ε-tubulin is essential in Tetrahymena thermophila for the assembly and stability of basal bodies

The Evolution of Eukaryotic Cilia and Flagella as Motile and Sensory Organelles

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