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Kos P, Baumann O. Spatial arrangement, polarity, and posttranslational modifications of the microtubule system in the Drosophila eye. Cell Tissue Res 2024:10.1007/s00441-024-03914-6. [PMID: 39152365 DOI: 10.1007/s00441-024-03914-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 08/02/2024] [Indexed: 08/19/2024]
Abstract
We have analyzed the organization of the microtubule system in photoreceptor cells and pigment cells within the adult Drosophila compound eye. Immunofluorescence localization of tubulin and of Short stop, a spectraplakin that has been reported to be involved in the anchorage of microtubule minus ends at the membrane, suggests the presence of non-centrosomal microtubule-organizing centers at the distal tip of the visual cells. Ultrastructural analyses confirm that microtubules emanate from membrane-associated plaques at the site of contact with cone cells and that all microtubules are aligned in distal-proximal direction within the photoreceptor cells. Determination of microtubule polarities demonstrated that about 95% of the microtubules in photoreceptor cells are oriented with their plus end in the direction of the synapse. Pigment cells in the eye contain only microtubules aligned in distal-proximal direction, with their plus end pointing towards the retinal floor. There, two populations of microtubules can be distinguished, single microtubules and bundled microtubules, the latter associated with actin filaments. Whereas microtubules in both photoreceptor cells and pigment cells are acetylated and mono/bi-glutamylated on α-tubulin, bundled microtubules in pigment cells are apparently also mono/bi-glutamylated on β-tubulin, providing the possibility of binding different microtubule-associated proteins.
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Affiliation(s)
- Piotr Kos
- Unit of Animal Physiology, Institute of Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany
| | - Otto Baumann
- Unit of Animal Physiology, Institute of Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany.
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2
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Dechaud C, Miyake S, Martinez-Bengochea A, Schartl M, Volff JN, Naville M. Clustering of Sex-Biased Genes and Transposable Elements in the Genome of the Medaka Fish Oryzias latipes. Genome Biol Evol 2021; 13:6384576. [PMID: 34623422 PMCID: PMC8633743 DOI: 10.1093/gbe/evab230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/17/2022] Open
Abstract
Although genes with similar expression patterns are sometimes found in the same genomic regions, almost nothing is known about the relative organization in genomes of genes and transposable elements (TEs), which might influence each other at the regulatory level. In this study, we used transcriptomic data from male and female gonads of the Japanese medaka Oryzias latipes to define sexually biased genes and TEs and analyze their relative genomic localization. We identified 20,588 genes expressed in the adult gonads of O. latipes. Around 39% of these genes are differentially expressed between male and female gonads. We further analyzed the expression of TEs using the program SQuIRE and showed that more TE copies are overexpressed in testis than in ovaries (36% vs. 10%, respectively). We then developed a method to detect genomic regions enriched in testis- or ovary-biased genes. This revealed that sex-biased genes and TEs are not randomly distributed in the genome and a part of them form clusters with the same expression bias. We also found a correlation of expression between TE copies and their closest genes, which increases with decreasing intervening distance. Such a genomic organization suggests either that TEs hijack the regulatory sequences of neighboring sexual genes, allowing their expression in germ line cells and consequently new insertions to be transmitted to the next generation, or that TEs are involved in the regulation of sexual genes, and might therefore through their mobility participate in the rewiring of sex regulatory networks.
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Affiliation(s)
- Corentin Dechaud
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | - Sho Miyake
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | | | - Manfred Schartl
- Entwicklungsbiochemie, Biozentrum, Universität Würzburg, Würzburg, Germany.,Department of Chemistry and Biochemistry, The Xiphophorus Genetic Stock Center, Texas State University, San Marcos, Texas, USA
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
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3
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Identification of DmTTLL5 as a Major Tubulin Glutamylase in the Drosophila Nervous System. Sci Rep 2017; 7:16254. [PMID: 29176602 PMCID: PMC5701211 DOI: 10.1038/s41598-017-16586-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/14/2017] [Indexed: 01/09/2023] Open
Abstract
Microtubules (MTs) play crucial roles during neuronal life. They are formed by heterodimers of alpha and beta-tubulins, which are subjected to several post-translational modifications (PTMs). Amongst them, glutamylation consists in the reversible addition of a variable number of glutamate residues to the C-terminal tails of tubulins. Glutamylation is the most abundant MT PTM in the mammalian adult brain, suggesting that it plays an important role in the nervous system (NS). Here, we show that the previously uncharacterized CG31108 gene encodes an alpha-tubulin glutamylase acting in the Drosophila NS. We show that this glutamylase, which we named DmTTLL5, initiates MT glutamylation specifically on alpha-tubulin, which are the only glutamylated tubulin in the Drosophila brain. In DmTTLL5 mutants, MT glutamylation was not detected in the NS, allowing for determining its potential function. DmTTLL5 mutants are viable and we did not find any defect in vesicular axonal transport, synapse morphology and larval locomotion. Moreover, DmTTLL5 mutant flies display normal negative geotaxis behavior and their lifespan is not altered. Thus, our work identifies DmTTLL5 as the major enzyme responsible for initiating neuronal MT glutamylation specifically on alpha-tubulin and we show that the absence of MT glutamylation is not detrimental for Drosophila NS function.
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4
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Jenkins BV, Saunders HAJ, Record HL, Johnson-Schlitz DM, Wildonger J. Effects of mutating α-tubulin lysine 40 on sensory dendrite development. J Cell Sci 2017; 130:4120-4131. [PMID: 29122984 PMCID: PMC5769580 DOI: 10.1242/jcs.210203] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/06/2017] [Indexed: 12/28/2022] Open
Abstract
Microtubules are essential for neuronal structure and function. Axonal and dendritic microtubules are enriched in post-translational modifications that impact microtubule dynamics, transport and microtubule-associated proteins. Acetylation of α-tubulin lysine 40 (K40) is a prominent and conserved modification of neuronal microtubules. However, the cellular role of microtubule acetylation remains controversial. To resolve how microtubule acetylation might affect neuronal morphogenesis, we mutated endogenous α-tubulin in vivo using a new Drosophila strain that facilitates the rapid knock-in of designer αTub84B alleles (the predominant α-tubulin-encoding gene in flies). Leveraging our new strain, we found that microtubule acetylation, as well as polyglutamylation and (de)tyrosination, is not essential for survival. However, we found that dendrite branch refinement in sensory neurons relies on α-tubulin K40. Mutagenesis of K40 reveals moderate yet significant changes in dendritic lysosome transport, microtubule polymerization and Futsch protein distribution in dendrites but not in axons. Our studies point to an unappreciated role for α-tubulin K40 and acetylation in dendrite morphogenesis. While our results are consistent with the idea that acetylation tunes microtubule function within neurons, they also suggest there may be an acetylation-independent requirement for α-tubulin K40. This article has an associated First Person interview with the first author of the paper. Highlighted Article: Neurons are enriched in post-translationally modified microtubules. Targeted mutagenesis of endogenous α-tubulin in flies reveals that dendrite branch refinement is altered by acetylation-blocking mutations.
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Affiliation(s)
- Brian V Jenkins
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Harriet A J Saunders
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA.,Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Helena L Record
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | - Jill Wildonger
- Biochemistry Department, University of Wisconsin-Madison, Madison, WI 53706, USA
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5
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Bayless BA, Galati DF, Junker AD, Backer CB, Gaertig J, Pearson CG. Asymmetrically localized proteins stabilize basal bodies against ciliary beating forces. J Cell Biol 2016; 215:457-466. [PMID: 27807131 PMCID: PMC5119938 DOI: 10.1083/jcb.201604135] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/24/2016] [Accepted: 10/04/2016] [Indexed: 11/26/2022] Open
Abstract
Basal bodies (BBs) organize and anchor motile cilia. This study uncovers components that asymmetrically localize to the rotationally symmetric BBs, where they fortify specific BB domains. Asymmetrically localized BB components are necessary to resist asymmetric ciliary forces. Basal bodies are radially symmetric, microtubule-rich structures that nucleate and anchor motile cilia. Ciliary beating produces asymmetric mechanical forces that are resisted by basal bodies. To resist these forces, distinct regions within the basal body ultrastructure and the microtubules themselves must be stable. However, the molecular components that stabilize basal bodies remain poorly defined. Here, we determine that Fop1 functionally interacts with the established basal body stability components Bld10 and Poc1. We find that Fop1 and microtubule glutamylation incorporate into basal bodies at distinct stages of assembly, culminating in their asymmetric enrichment at specific triplet microtubule regions that are predicted to experience the greatest mechanical force from ciliary beating. Both Fop1 and microtubule glutamylation are required to stabilize basal bodies against ciliary beating forces. Our studies reveal that microtubule glutamylation and Bld10, Poc1, and Fop1 stabilize basal bodies against the forces produced by ciliary beating via distinct yet interdependent mechanisms.
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Affiliation(s)
- Brian A Bayless
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Domenico F Galati
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Anthony D Junker
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Chelsea B Backer
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Chad G Pearson
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
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6
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Ohta S, Hamada M, Sato N, Toramoto I. Polyglutamylated Tubulin Binding Protein C1orf96/CSAP Is Involved in Microtubule Stabilization in Mitotic Spindles. PLoS One 2015; 10:e0142798. [PMID: 26562023 PMCID: PMC4642972 DOI: 10.1371/journal.pone.0142798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/27/2015] [Indexed: 12/13/2022] Open
Abstract
The centrosome-associated C1orf96/Centriole, Cilia and Spindle-Associated Protein (CSAP) targets polyglutamylated tubulin in mitotic microtubules (MTs). Loss of CSAP causes critical defects in brain development; however, it is unclear how CSAP association with MTs affects mitosis progression. In this study, we explored the molecular mechanisms of the interaction of CSAP with mitotic spindles. Loss of CSAP caused MT instability in mitotic spindles and resulted in mislocalization of Nuclear protein that associates with the Mitotic Apparatus (NuMA), with defective MT dynamics. Thus, CSAP overload in the spindles caused extensive MT stabilization and recruitment of NuMA. Moreover, MT stabilization by CSAP led to high levels of polyglutamylation on MTs. MT depolymerization by cold or nocodazole treatment was inhibited by CSAP binding. Live-cell imaging analysis suggested that CSAP-dependent MT-stabilization led to centrosome-free MT aster formation immediately upon nuclear envelope breakdown without γ-tubulin. We therefore propose that CSAP associates with MTs around centrosomes to stabilize MTs during mitosis, ensuring proper bipolar spindle formation and maintenance.
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Affiliation(s)
- Shinya Ohta
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
- * E-mail:
| | - Mayako Hamada
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
| | - Nobuko Sato
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
| | - Iyo Toramoto
- From the Center for Innovative and Translational Medicine, Medical School, Kochi University, Kohasu, Oko-cho, Nankoku, Kochi, Japan
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7
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Ludueña RF. A Hypothesis on the Origin and Evolution of Tubulin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 302:41-185. [DOI: 10.1016/b978-0-12-407699-0.00002-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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8
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Abstract
Drosophila melanogaster spermatids undergo dramatic morphological changes as they differentiate from small round cells approximately 12 μm in diameter into highly polarized, 1.8 mm long, motile sperm capable of participating in fertilization. During spermiogenesis, syncytial cysts of 64 haploid spermatids undergo synchronous differentiation. Numerous changes occur at a subcellular level, including remodeling of existing organelles (mitochondria, nuclei), formation of new organelles (flagellar axonemes, acrosomes), polarization of elongating cysts and plasma membrane addition. At the end of spermatid morphogenesis, organelles, mitochondrial DNA and cytoplasmic components not needed in mature sperm are stripped away in a caspase-dependent process called individualization that results in formation of individual sperm. Here, we review the stages of Drosophila spermiogenesis and examine our current understanding of the cellular and molecular mechanisms involved in shaping male germ cell-specific organelles and forming mature, fertile sperm.
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Affiliation(s)
- Lacramioara Fabian
- Cell Biology Program; The Hospital for Sick Children (SickKids); Toronto, ON Canada
| | - Julie A. Brill
- Cell Biology Program; The Hospital for Sick Children (SickKids); Toronto, ON Canada
- Department of Molecular Genetics; University of Toronto; Toronto, ON Canada
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9
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Klp10A, a microtubule-depolymerizing kinesin-13, cooperates with CP110 to control Drosophila centriole length. Curr Biol 2012; 22:502-9. [PMID: 22365849 DOI: 10.1016/j.cub.2012.01.046] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 12/06/2011] [Accepted: 01/24/2012] [Indexed: 11/22/2022]
Abstract
Klp10A is a kinesin-13 of Drosophila melanogaster that depolymerizes cytoplasmic microtubules. In interphase, it promotes microtubule catastrophe; in mitosis, it contributes to anaphase chromosome movement by enabling tubulin flux. Here we show that Klp10A also acts as a microtubule depolymerase on centriolar microtubules to regulate centriole length. Thus, in both cultured cell lines and the testes, absence of Klp10A leads to longer centrioles that show incomplete 9-fold symmetry at their ends. These structures and associated pericentriolar material undergo fragmentation. We also show that in contrast to mammalian cells where depletion of CP110 leads to centriole elongation, in Drosophila cells it results in centriole length diminution that is overcome by codepletion of Klp10A to give longer centrioles than usual. We discuss how loss of centriole capping by CP110 might have different consequences for centriole length in mammalian and insect cells and also relate these findings to the functional interactions between mammalian CP110 and another kinesin-13, Kif24, that in mammalian cells regulates cilium formation.
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10
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Hoyle HD, Turner FR, Raff EC. Axoneme-dependent tubulin modifications in singlet microtubules of the Drosophila sperm tail. ACTA ACUST UNITED AC 2008; 65:295-313. [PMID: 18205200 DOI: 10.1002/cm.20261] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Drosophila melanogaster sperm tubulins are posttranslationally glutamylated and glycylated. We show here that axonemes are the substrate for these tubulin C-terminal modifications. Axoneme architecture is required, but full length, motile axonemes are not necessary. Tubulin glutamylation occurs during or shortly after assembly into the axoneme; only glutamylated tubulins are glycylated. Tubulins in other testis microtubules are not modified. Only a small subset of total Drosophila sperm axoneme tubulins have these modifications. Biochemical fractionation of Drosophila sperm showed that central pair and accessory microtubules have the majority of poly-modified tubulins, whereas doublet microtubules have only small amounts of mono- and oligo-modified tubulins. Glutamylation patterns for different beta-tubulins experimentally assembled into axonemes were consistent with utilization of modification sites corresponding to those identified in other organisms, but surrounding sequence context was also important. We compared tubulin modifications in the 9 + 9 + 2 insect sperm tail axonemes of Drosophila with the canonical 9 + 2 axonemes of sperm of the sea urchin Lytichinus pictus and the 9 + 0 motile sperm axonemes of the eel Anguilla japonica. In contrast to Drosophila sperm, L. pictus sperm have equivalent levels of modified tubulins in both doublet and central pair microtubule fractions, whereas the doublets of A. japonica sperm exhibit little glutamylation but extensive glycylation. Tubulin C-terminal modifications are a prevalent feature of motile axonemes, but there is no conserved pattern for placement or amount of these
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Affiliation(s)
- Henry D Hoyle
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
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11
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Popodi EM, Hoyle HD, Turner FR, Xu K, Kruse S, Raff EC. Axoneme specialization embedded in a “Generalist” β-tubulin. ACTA ACUST UNITED AC 2008; 65:216-37. [DOI: 10.1002/cm.20256] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Mencarelli C, Lupetti P, Dallai R. New insights into the cell biology of insect axonemes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 268:95-145. [PMID: 18703405 DOI: 10.1016/s1937-6448(08)00804-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insects do not possess ciliated epithelia, and cilia/flagella are present in the sperm tail and--as modified cilia--in mechano- and chemosensory neurons. The core cytoskeletal component of these organelles, the axoneme, is a microtubule-based structure that has been conserved throughout evolution. However, in insects the sperm axoneme exhibits distinctive structural features; moreover, several insect groups are characterized by an unusual sperm axoneme variability. Besides the abundance of morphological data on insect sperm flagella, most of the available molecular information on the insect axoneme comes from genetic studies on Drosophila spermatogenesis, and only recently other insect species have been proposed as useful models. Here, we review the current knowledge on the cell biology of insect axoneme, including contributions from both Drosophila and other model insects.
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Affiliation(s)
- C Mencarelli
- Department of Evolutionary Biology, University of Siena, 53100 Siena, Italy
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13
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Spéder P, Adám G, Noselli S. Type ID unconventional myosin controls left-right asymmetry in Drosophila. Nature 2006; 440:803-7. [PMID: 16598259 DOI: 10.1038/nature04623] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 02/01/2006] [Indexed: 01/06/2023]
Abstract
Breaking left-right symmetry in Bilateria embryos is a major event in body plan organization that leads to polarized adult morphology, directional organ looping, and heart and brain function. However, the molecular nature of the determinant(s) responsible for the invariant orientation of the left-right axis (situs choice) remains largely unknown. Mutations producing a complete reversal of left-right asymmetry (situs inversus) are instrumental for identifying mechanisms controlling handedness, yet only one such mutation has been found in mice (inversin) and snails. Here we identify the conserved type ID unconventional myosin 31DF gene (Myo31DF) as a unique situs inversus locus in Drosophila. Myo31DF mutations reverse the dextral looping of genitalia, a prominent left-right marker in adult flies. Genetic mosaic analysis pinpoints the A8 segment of the genital disc as a left-right organizer and reveals an anterior-posterior compartmentalization of Myo31DF function that directs dextral development and represses a sinistral default state. As expected of a determinant, Myo31DF has a trigger-like function and is expressed symmetrically in the organizer, and its symmetrical overexpression does not impair left-right asymmetry. Thus Myo31DF is a dextral gene with actin-based motor activity controlling situs choice. Like mouse inversin, Myo31DF interacts and colocalizes with beta-catenin, suggesting that situs inversus genes can direct left-right development through the adherens junction.
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Affiliation(s)
- Pauline Spéder
- Institute of Signalling, Developmental Biology & Cancer, UMR6543-CNRS, University of Nice Sophia-Antipolis, Parc Valrose, 06108 Nice Cedex 2, France
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14
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Mencarelli C, Caroti D, Bré MH, Levilliers N, Mercati D, Robbins LG, Dallai R. Glutamylated and glycylated tubulin isoforms in the aberrant sperm axoneme of the gall-midge fly, Asphondylia ruebsaameni. ACTA ACUST UNITED AC 2005; 58:160-74. [PMID: 15146535 DOI: 10.1002/cm.20000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The axonemal organization expressed in the sperm flagella of the cecidomyiid dipteran Asphondylia ruebsaameni is unconventional, being characterized by the presence of an exceedingly high number of microtubular doublets and by the absence of both the inner dynein arms and the central pair/radial spoke complex. Consequently, its motility, both in vivo and in vitro, is also peculiar. Using monoclonal antibodies directed against posttranslational modifications, we have analyzed the presence and distribution of glutamylated and glycylated tubulin isoforms in this aberrant axonemal structure, and compared them with those of a reference insect species (Apis mellifera), endowed with a conventional axoneme. Our results have shown that the unorthodox structure and motility of the Asphondylia axoneme are concomitant with: (1). a very low glutamylation extent in the alpha-tubulin subunit, (2). a high level of glutamylation in the beta-subunit, (3). an extremely low total extent of glycylation, with regard to both monoglycylated and polyglycylated sites, either in alpha- or in beta-tubulin, (4). the presence of a strong labeling of glutamylated tubulin isoforms at the proximal end of the axoneme, and (5). a uniform distribution of glutamylated as well as glycylated isoforms along the rest of the axoneme. Thus, our data indicate that tubulin molecular heterogeneity is much lower in the Asphondylia axoneme than in the conventional 9+2 axoneme with regard to both isoform content and isoform distribution along the axoneme.
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15
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Popodi EM, Hoyle HD, Turner FR, Raff EC. The proximal region of the β-tubulin C-terminal tail is sufficient for axoneme assembly. ACTA ACUST UNITED AC 2005; 62:48-64. [PMID: 16080206 DOI: 10.1002/cm.20085] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have used Drosophila testis-specific beta2-tubulin to determine sequence requirements for different microtubules. The beta2-tubulin C-terminal tail has unique sperm-specific functions [Dev Biol 158:267-286 (2003)] and is also important for forming stable heterodimers with alpha-tubulin, a general function common to all microtubules [Mol Biol Cell 12(7):2185-2194 (2001)]. beta-tubulins utilized in motile 9 + 2 axonemes contain a C-terminal sequence "axoneme motif" [Science 275 (1997) 70-73]. C-terminal truncated beta2-tubulin cannot form the sperm tail axoneme. Here we show that a partially truncated beta2-tubulin (beta2Delta7) containing only the proximal portion of the C-terminal tail, including the axoneme motif, can support production of functional motile sperm. We conclude that these proximal eight amino acids specify the binding site for protein(s) essential to support assembly of the motile axoneme. Males that express beta2Delta7, although they are fertile, produce fewer sperm than wild type males. Beta2Delta7 causes a slightly increased error rate in spermatogenesis attributable to loss of stabilizing properties intrinsic to the full-length C-terminal tail. Therefore, beta2Delta7 males would be at a selective disadvantage and it is likely that the full-length C-terminus would be essential in the wild and in evolution.
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Affiliation(s)
- Ellen M Popodi
- Department of Biology and Indiana Molecular Biology Institute, Indiana University, Bloomington, Indiana 47405, USA.
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16
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Li JB, Gerdes JM, Haycraft CJ, Fan Y, Teslovich TM, May-Simera H, Li H, Blacque OE, Li L, Leitch CC, Lewis RA, Green JS, Parfrey PS, Leroux MR, Davidson WS, Beales PL, Guay-Woodford LM, Yoder BK, Stormo GD, Katsanis N, Dutcher SK. Comparative genomics identifies a flagellar and basal body proteome that includes the BBS5 human disease gene. Cell 2004; 117:541-52. [PMID: 15137946 DOI: 10.1016/s0092-8674(04)00450-7] [Citation(s) in RCA: 569] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2004] [Revised: 04/22/2004] [Accepted: 04/23/2004] [Indexed: 10/26/2022]
Abstract
Cilia and flagella are microtubule-based structures nucleated by modified centrioles termed basal bodies. These biochemically complex organelles have more than 250 and 150 polypeptides, respectively. To identify the proteins involved in ciliary and basal body biogenesis and function, we undertook a comparative genomics approach that subtracted the nonflagellated proteome of Arabidopsis from the shared proteome of the ciliated/flagellated organisms Chlamydomonas and human. We identified 688 genes that are present exclusively in organisms with flagella and basal bodies and validated these data through a series of in silico, in vitro, and in vivo studies. We then applied this resource to the study of human ciliation disorders and have identified BBS5, a novel gene for Bardet-Biedl syndrome. We show that this novel protein localizes to basal bodies in mouse and C. elegans, is under the regulatory control of daf-19, and is necessary for the generation of both cilia and flagella.
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Affiliation(s)
- Jin Billy Li
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
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17
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Bobinnec Y, Fukuda M, Nishida E. Identification and characterization of Caenorhabditis elegans gamma-tubulin in dividing cells and differentiated tissues. J Cell Sci 2000; 113 Pt 21:3747-59. [PMID: 11034903 DOI: 10.1242/jcs.113.21.3747] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
gamma-Tubulin is an essential component of the microtubule-nucleation machinery and therefore plays a crucial role during mitosis. To gain further insights into the function of this protein in the events that take place during embryogenesis and differentiation, we carried out detailed studies on gamma-tubulin during all the developmental stages of Caenorhabditis elegans. We identified the gamma-tubulin gene from this organism and analyzed the localization of the protein by both immunofluorescence and GFP reporter construct. We show that gamma-tubulin association with the centrosome is highly dynamic in mitotic cells, being massively recruited at prophase and released at anatelophase. This accumulation in mitotic centrosomes is dramatic during the first embryonic divisions. We provide the first description of the morphological changes at the centrosome level during the orientation of the mitotic spindle and the flattening of the posterior aster. Loss of function of the gamma-tubulin gene by RNAi induces a strong polyploidization of mitotic germ cells and embryos, but does not affect meiosis and pronuclear migration. In addition, we demonstrate the prominent redistribution of gamma-tubulin in adults at basal bodies of amphid and phasmid neurons, and at the apical membrane of polarized intestinal cells.
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Affiliation(s)
- Y Bobinnec
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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