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Yuan S, Li Y, Wang L, Xu F, Chen J, Levin MG, Xiong Y, Voight BF, Damrauer SM, Gill D, Burgess S, Åkesson A, Michaëlsson K, Li X, Shen X, Larsson SC. Deciphering the genetic architecture of atrial fibrillation offers insights into disease prediction, pathophysiology and downstream sequelae. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.07.20.23292938. [PMID: 37546828 PMCID: PMC10402218 DOI: 10.1101/2023.07.20.23292938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Aims The study aimed to discover novel genetic loci for atrial fibrillation (AF), explore the shared genetic etiologies between AF and other cardiovascular and cardiometabolic traits, and uncover AF pathogenesis using Mendelian randomization analysis. Methods and results We conducted a genome-wide association study meta-analysis including 109,787 AF cases and 1,165,920 controls of European ancestry and identified 215 loci, among which 91 were novel. We performed Genomic Structural Equation Modeling analysis between AF and four cardiovascular comorbidities (coronary artery disease, ischemic stroke, heart failure, and vneous thromboembolism) and found 189 loci shared across these diseases as well as a universal genetic locus shared by atherosclerotic outcomes (i.e., rs1537373 near CDKN2B). Three genetic loci (rs10740129 near JMJD1C, rs2370982 near NRXN3, and rs9931494 near FTO) were associated with AF and cardiometabolic traits. A polygenic risk score derived from this genome-wide meta-analysis was associated with AF risk (odds ratio 2.36, 95% confidence interval 2.31-2.41 per standard deviation increase) in the UK biobank. This score, combined with age, sex, and basic clinical features, predicted AF risk (AUC 0.784, 95% CI 0.781-0.787) in Europeans. Phenome-wide association analysis of the polygenic risk score identified many AF-related comorbidities of the circulatory, endocrine, and respiratory systems. Phenome-wide and multi-omic Mendelian randomization analyses identified associations of blood lipids and pressure, diabetes, insomnia, obesity, short sleep, and smoking, 27 blood proteins, one gut microbe (genus.Catenibacterium), and 11 blood metabolites with risk to AF. Conclusions This genome-wide association study and trans-omic Mendelian randomization analysis provides insights into disease risk prediction, pathophysiology and downstream sequelae.
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Affiliation(s)
- Shuai Yuan
- Unit of Cardiovascular and Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Yuying Li
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Lijuan Wang
- School of Public Health and The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Fengzhe Xu
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Jie Chen
- School of Public Health and The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Michael G Levin
- Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
| | - Ying Xiong
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Benjamin F. Voight
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
- Institute of Translational Medicine and Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Scott M Damrauer
- Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Surgery, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom
| | - Stephen Burgess
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Agneta Åkesson
- Unit of Cardiovascular and Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Karl Michaëlsson
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Xue Li
- School of Public Health and The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xia Shen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
- Center for Intelligent Medicine Research, Greater Bay Area Institute of Precision Medicine (Guangzhou), Fudan University, Guangzhou, China
- Centre for Global Health Research, Usher Institute, University of Edinburgh, Edinburgh, UK
| | - Susanna C. Larsson
- Unit of Cardiovascular and Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Unit of Medical Epidemiology, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
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Roles for microtubules in the proliferative and differentiated cells of stratified epithelia. Curr Opin Cell Biol 2020; 68:98-104. [PMID: 33186891 DOI: 10.1016/j.ceb.2020.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 12/27/2022]
Abstract
While microtubule dynamics and organization have been extensively studied invitro, both biochemically and in cultured cells, recent work has begun to extend this into tissues ex vivo and organisms in vivo. Advances in genetic tools and imaging technology have allowed studies on the dynamics, function, and organization of microtubules in the stratified epithelia of the epidermis. Here, we discuss recent work that highlights the varied roles that microtubules play in supporting epidermal function. These findings demonstrate that studying microtubules in tissues has revealed not only novel aspects of epidermal biology but also new principles of microtubule regulation.
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3
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Emond MR, Biswas S, Morrow ML, Jontes JD. Proximity-dependent Proteomics Reveals Extensive Interactions of Protocadherin-19 with Regulators of Rho GTPases and the Microtubule Cytoskeleton. Neuroscience 2020; 452:26-36. [PMID: 33010346 DOI: 10.1016/j.neuroscience.2020.09.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/02/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
Protocadherin-19 belongs to the cadherin family of cell surface receptors and has been shown to play essential roles in the development of the vertebrate nervous system. Mutations in human Protocadherin-19 (PCDH19) lead to PCDH19 Female-limited epilepsy (PCDH19 FLE) in humans, characterized by the early onset of epileptic seizures in children and a range of cognitive and behavioral problems in adults. Despite being considered the second most prevalent gene in epilepsy, very little is known about the intercellular pathways in which it participates. In order to characterize the protein complexes within which Pcdh19 functions, we generated Pcdh19-BioID fusion proteins and utilized proximity-dependent biotinylation to identify neighboring proteins. Proteomic identification and analysis revealed that the Pcdh19 interactome is enriched in proteins that regulate Rho family GTPases, microtubule binding proteins and proteins that regulate cell divisions. We cloned the centrosomal protein Nedd1 and the RacGEF Dock7 and verified their interactions with Pcdh19 in vitro. Our findings provide the first comprehensive insights into the interactome of Pcdh19, and provide a platform for future investigations into the cellular and molecular biology of this protein critical to the proper development of the nervous system.
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Affiliation(s)
- Michelle R Emond
- Department of Neuroscience, Ohio State University, United States
| | | | - Matthew L Morrow
- Department of Neuroscience, Ohio State University, United States
| | - James D Jontes
- Department of Neuroscience, Ohio State University, United States.
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4
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Microtubule nucleation by γ-tubulin complexes and beyond. Essays Biochem 2018; 62:765-780. [PMID: 30315097 PMCID: PMC6281477 DOI: 10.1042/ebc20180028] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
In this short review, we give an overview of microtubule nucleation within cells. It is nearly 30 years since the discovery of γ-tubulin, a member of the tubulin superfamily essential for proper microtubule nucleation in all eukaryotes. γ-tubulin associates with other proteins to form multiprotein γ-tubulin ring complexes (γ-TuRCs) that template and catalyse the otherwise kinetically unfavourable assembly of microtubule filaments. These filaments can be dynamic or stable and they perform diverse functions, such as chromosome separation during mitosis and intracellular transport in neurons. The field has come a long way in understanding γ-TuRC biology but several important and unanswered questions remain, and we are still far from understanding the regulation of microtubule nucleation in a multicellular context. Here, we review the current literature on γ-TuRC assembly, recruitment, and activation and discuss the potential importance of γ-TuRC heterogeneity, the role of non-γ-TuRC proteins in microtubule nucleation, and whether γ-TuRCs could serve as good drug targets for cancer therapy.
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5
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McFarland RJ, Brown SP, Vital E, Werner JM, Brewster RM. Use of Immunolabeling to Analyze Stable, Dynamic, and Nascent Microtubules in the Zebrafish Embryo. J Vis Exp 2017. [PMID: 28994750 DOI: 10.3791/55792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Microtubules (MTs) are dynamic and fragile structures that are challenging to image in vivo, particularly in vertebrate embryos. Immunolabeling methods are described here to analyze distinct populations of MTs in the developing neural tube of the zebrafish embryo. While the focus is on neural tissue, this methodology is broadly applicable to other tissues. The procedures are optimized for early to mid-somitogenesis-stage embryos (1 somite to 12 somites), however they can be adapted to a range of other stages with relatively minor adjustments. The first protocol provides a method to assess the spatial distribution of stable and dynamic MTs and perform a quantitative analysis of these populations with image-processing software. This approach complements existing tools to image microtubule dynamics and distribution in real-time, using transgenic lines or transient expression of tagged constructs. Indeed, such tools are very useful, however they do not readily distinguish between dynamic and stable MTs. The ability to image and analyze these distinct microtubule populations has important implications for understanding mechanisms underlying cell polarization and morphogenesis. The second protocol outlines a technique to analyze nascent MTs specifically. This is accomplished by capturing the de novo growth properties of MTs over time, following microtubule depolymerization with the drug nocodazole and a recovery period after drug washout. This technique has not yet been applied to the study of MTs in zebrafish embryos, but is a valuable assay for investigating the in vivo function of proteins implicated in microtubule assembly.
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Affiliation(s)
| | - Sharlene P Brown
- Department of Biological Sciences, University of Maryland, Baltimore County
| | - Eudorah Vital
- Department of Biological Sciences, University of Maryland, Baltimore County
| | - Jonathan M Werner
- Department of Biological Sciences, University of Maryland, Baltimore County
| | - Rachel M Brewster
- Department of Biological Sciences, University of Maryland, Baltimore County;
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Song MH, Medley JC, Kuwada JY. The Zebrafish curly fry Is Required for Proper Centrosome and Mitotic Spindle Assembly. Zebrafish 2017; 14:311-321. [PMID: 28488934 DOI: 10.1089/zeb.2017.1427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The zebrafish curly fry (cfy) mutation leads to a dramatic increase in mitotic index and cell death starting during neural tube formation. The mutant phenotype is cell autonomous and does not result from defects in apical/basal polarity within the neuroepithelium. The increase in mitotic index could be due to increased proliferation or cell cycle arrest in mitosis. cfy embryos were analyzed to examine these two possibilities. By labeling embryos with a pulse of BrdU and anti-phospho-histone 3 and examining the DNA content by fluorescence activated cell sorting, we show that cfy mutants exhibit no increase in proliferation, but a significant increase in the number of cells arrested in mitosis. Furthermore, time-lapse microscopy in vivo confirmed that a great majority of dividing cells arrest during mitosis and that these mitotically arrested cells die in cfy embryos. Finally, immunostaining and confocal microscopy in cfy mutant embryos revealed that mitotic cells in mutants contain aberrant centrosomes and often exhibit monopolar spindles, thereby leading to mitotic cell cycle arrest. Our results suggest that the cfy gene is required for proper centrosome assembly and mitotic spindle formation, therefore critical for normal cell division.
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Affiliation(s)
- Mi Hye Song
- 1 Department of Biological Sciences, Oakland University , Rochester, Michigan
| | - Jeffrey C Medley
- 1 Department of Biological Sciences, Oakland University , Rochester, Michigan
| | - John Y Kuwada
- 2 Department of Molecular, Cellular and Developmental Biology, University of Michigan , Ann Arbor, Michigan
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7
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Nano M, Basto R. Consequences of Centrosome Dysfunction During Brain Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1002:19-45. [PMID: 28600781 DOI: 10.1007/978-3-319-57127-0_2] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Development requires cell proliferation, differentiation and spatial organization of daughter cells to occur in a highly controlled manner. The mode of cell division, the extent of proliferation and the spatial distribution of mitosis allow the formation of tissues of the right size and with the correct structural organization. All these aspects depend on cell cycle duration, correct chromosome segregation and spindle orientation. The centrosome, which is the main microtubule-organizing centre (MTOC) of animal cells, contributes to all these processes. As one of the most structurally complex organs in our body, the brain is particularly susceptible to centrosome dysfunction. Autosomal recessive primary microcephaly (MCPH), primordial dwarfism disease Seckel syndrome (SCKS) and microcephalic osteodysplastic primordial dwarfism type II (MOPD-II) are often connected to mutations in centrosomal genes. In this chapter, we discuss the consequences of centrosome dysfunction during development and how they can contribute to the etiology of human diseases.
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Affiliation(s)
- Maddalena Nano
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005, Paris, France.
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Kelu JJ, Chan HLH, Webb SE, Cheng AHH, Ruas M, Parrington J, Galione A, Miller AL. Two-Pore Channel 2 activity is required for slow muscle cell-generated Ca(2+) signaling during myogenesis in intact zebrafish. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2016; 59:313-25. [PMID: 26679948 DOI: 10.1387/ijdb.150206am] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
We have recently characterized essential inositol 1,4,5-trisphosphate receptor (IP 3R) and ryanodine receptor (RyR)-mediated Ca(2+) signals generated during the differentiation of slow muscle cells (SMCs) in intact zebrafish embryos. Here, we show that the lysosomal two-pore channel 2 (TPC2) also plays a crucial role in generating, and perhaps triggering, these essential Ca(2+) signals, and thus contributes to the regulation of skeletal muscle myogenesis. We used a transgenic line of zebrafish that expresses the bioluminescent Ca(2+) reporter, aequorin, specifically in skeletal muscle, in conjunction with morpholino (MO)-based and pharmacological inhibition of TPC2, in both intact embryos and isolated SMCs. MO-based knock-down of TPC2 resulted in a dramatic attenuation of the Ca(2+) signals, whereas the introduction of TPCN2-MO and TPCN2 mRNA together partially rescued the Ca(2+) signaling signature. Embryos treated with trans-ned-19 or bafilomycin A1, a specific NAADP receptor inhibitor and vacuolar-type H(+)ATPase inhibitor, respectively, also displayed a similar disruption of SMC Ca(2+) signaling. TPC2 and lysosomes were shown via immunohistochemistry and confocal laser scanning microscopy to be localized in perinuclear and striated cytoplasmic domains of SMCs, coincident with patterns of IP 3R and RyR expression. These data together imply that TPC2-mediated Ca(2+) release from lysosomes acts upstream from RyR- and IP 3R-mediated Ca(2+) release, suggesting that the former might act as a sensitive trigger to initiate the SR-mediated Ca(2+)-induced-Ca(2+)-release essential for SMC myogenesis and function.
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Affiliation(s)
- Jeffrey J Kelu
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, HKUST, Clear Water Bay, Hong Kong, PRC
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Muroyama A, Seldin L, Lechler T. Divergent regulation of functionally distinct γ-tubulin complexes during differentiation. J Cell Biol 2016; 213:679-92. [PMID: 27298324 PMCID: PMC4915192 DOI: 10.1083/jcb.201601099] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/29/2016] [Indexed: 11/22/2022] Open
Abstract
Differentiation induces the formation of noncentrosomal microtubule arrays in diverse tissues. The formation of these arrays requires loss of microtubule-organizing activity (MTOC) at the centrosome, but the mechanisms regulating this transition remain largely unexplored. Here, we use the robust loss of centrosomal MTOC activity in the epidermis to identify two pools of γ-tubulin that are biochemically and functionally distinct and differentially regulated. Nucleation-competent CDK5RAP2-γ-tubulin complexes were maintained at centrosomes upon initial epidermal differentiation. In contrast, Nedd1-γ-tubulin complexes did not promote nucleation but were required for anchoring of microtubules, a previously uncharacterized activity for this complex. Cell cycle exit specifically triggered loss of Nedd1-γ-tubulin complexes, providing a mechanistic link connecting MTOC activity and differentiation. Collectively, our studies demonstrate that distinct γ-tubulin complexes regulate different microtubule behaviors at the centrosome and show that differential regulation of these complexes drives loss of centrosomal MTOC activity.
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Affiliation(s)
- Andrew Muroyama
- Department of Dermatology, Duke University Medical Center, Durham, NC 27710 Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
| | - Lindsey Seldin
- Department of Dermatology, Duke University Medical Center, Durham, NC 27710 Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
| | - Terry Lechler
- Department of Dermatology, Duke University Medical Center, Durham, NC 27710 Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
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Chu CW, Ossipova O, Ioannou A, Sokol SY. Prickle3 synergizes with Wtip to regulate basal body organization and cilia growth. Sci Rep 2016; 6:24104. [PMID: 27062996 PMCID: PMC4827067 DOI: 10.1038/srep24104] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/21/2016] [Indexed: 12/21/2022] Open
Abstract
PCP proteins maintain planar polarity in many epithelial tissues and have been implicated in cilia development in vertebrate embryos. In this study we examine Prickle3 (Pk3), a vertebrate homologue of Drosophila Prickle, in Xenopus gastrocoel roof plate (GRP). GRP is a tissue equivalent to the mouse node, in which cilia-generated flow promotes left-right patterning. We show that Pk3 is enriched at the basal body of GRP cells but is recruited by Vangl2 to anterior cell borders. Interference with Pk3 function disrupted the anterior polarization of endogenous Vangl2 and the posterior localization of cilia in GRP cells, demonstrating its role in PCP. Strikingly, in cells with reduced Pk3 activity, cilia growth was inhibited and γ-tubulin and Nedd1 no longer associated with the basal body, suggesting that Pk3 has a novel function in basal body organization. Mechanistically, this function of Pk3 may involve Wilms tumor protein 1-interacting protein (Wtip), which physically associates with and cooperates with Pk3 to regulate ciliogenesis. We propose that, in addition to cell polarity, PCP components control basal body organization and function.
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Affiliation(s)
- Chih-Wen Chu
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Olga Ossipova
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andriani Ioannou
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sergei Y Sokol
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Chung HY, Chang CT, Young HW, Hu SP, Tzou WS, Hu CH. Ethanol inhibits retinal and CNS differentiation due to failure of cell cycle exit via an apoptosis-independent pathway. Neurotoxicol Teratol 2013; 38:92-103. [DOI: 10.1016/j.ntt.2013.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/25/2013] [Accepted: 05/16/2013] [Indexed: 11/24/2022]
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12
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Remy MH, Merdes A, Gregory-Pauron L. Assembly of Gamma-Tubulin Ring Complexes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:511-30. [DOI: 10.1016/b978-0-12-386931-9.00019-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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13
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Reschen RF, Colombie N, Wheatley L, Dobbelaere J, St Johnston D, Ohkura H, Raff JW. Dgp71WD is required for the assembly of the acentrosomal Meiosis I spindle, and is not a general targeting factor for the γ-TuRC. Biol Open 2012; 1:422-9. [PMID: 23213433 PMCID: PMC3507215 DOI: 10.1242/bio.2012596] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dgp71WD/Nedd1 proteins are essential for mitotic spindle formation. In human cells, Nedd1 targets γ-tubulin to both centrosomes and spindles, but in other organisms the function of Dgp71WD/Nedd1 is less clear. In Drosophila cells, Dgp71WD plays a major part in targeting γ-tubulin to spindles, but not centrosomes, while in Xenopus egg extracts, Nedd1 acts as a more general microtubule (MT) organiser that can function independently of γ-tubulin. The interpretation of these studies, however, is complicated by the fact that some residual Dgp71WD/Nedd1 is likely present in the cells/extracts analysed. Here we generate a Dgp71WD null mutant lacking all but the last 12 nucleotides of coding sequence. The complete loss of Dgp71WD has no quantifiable effect on γ-tubulin or Centrosomin recruitment to the centrosome in larval brain cells. The recruitment of γ-tubulin to spindle MTs, however, is severely impaired, and spindle MT density is reduced in a manner that is indistinguishable from cells lacking Augmin or γ-TuRC function. In contrast, the absence of Dgp71WD leads to defects in the assembly of the acentrosomal female Meiosis I spindle that are more severe than those seen in Augmin or γ-TuRC mutants, indicating that Dgp71WD has additional functions that are independent of these complexes in oocytes. Moreover, the localisation of bicoid RNA during oogenesis, which requires γ-TuRC function, is unperturbed in Dgp71WD(120) mutants. Thus, Dgp71WD is not simply a general cofactor required for γ-TuRC and/or Augmin targeting, and it appears to have a crucial role independent of these complexes in the acentrosomal Meiosis I spindle.
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Affiliation(s)
- Richard F. Reschen
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Nathalie Colombie
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh, EH9 3JR, UK
| | - Lucy Wheatley
- Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Jeroen Dobbelaere
- Research Institute of Molecular Pathology (IMP), Dr. Bohr-Gasse 7, 1030 Vienna, Austria
| | - Daniel St Johnston
- Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Hiro Ohkura
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Kings Buildings, Mayfield Road, Edinburgh, EH9 3JR, UK
| | - Jordan W. Raff
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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Manning JA, Kumar S. A potential role for NEDD1 and the centrosome in senescence of mouse embryonic fibroblasts. Cell Death Dis 2010; 1:e35. [PMID: 21364642 PMCID: PMC3032305 DOI: 10.1038/cddis.2010.12] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mouse embryonic fibroblasts (MEFs) are commonly grown in cell culture and are known to enter senescence after a low number of passages as a result of oxidative stress. Oxidative stress has also been suggested to promote centrosome disruption; however, the contribution of this organelle to senescence is poorly understood. Therefore, this study aimed to assess the role of the centrosome in oxidative stress induced-senescence using MEFs as a model. We demonstrate here that coincident with the entry of late-passage MEFs into senescence, there was an increase in supernumerary centrosomes, most likely due to centrosome fragmentation. In addition, disrupting the centrosome in early-passage MEFs by depletion of neural precursor cell expressed developmentally downregulated gene 1 (NEDD1) also resulted in centrosomal fragmentation and subsequent premature entry into senescence. These data show that a loss of centrosomal integrity may contribute to the entry of MEFs into senescence in culture, and that centrosomal disruption can cause senescence.
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Affiliation(s)
- J A Manning
- Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
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