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Chi YH, Wang WP, Hung MC, Liou GG, Wang JY, Chao PHG. Deformation of the nucleus by TGFβ1 via the remodeling of nuclear envelope and histone isoforms. Epigenetics Chromatin 2022; 15:1. [PMID: 34983624 PMCID: PMC8725468 DOI: 10.1186/s13072-021-00434-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/24/2021] [Indexed: 11/18/2022] Open
Abstract
The cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFβ1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFβ1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, clustering at the nuclear periphery and reintegrating into the nucleoplasm. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFβ1-induced compositional changes in the chromatin and nuclear lamina.
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Affiliation(s)
- Ya-Hui Chi
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan. .,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, 40402, Taiwan.
| | - Wan-Ping Wang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Ming-Chun Hung
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Gunn-Guang Liou
- National Taiwan University College of Medicine, Taipei, 10051, Taiwan
| | - Jing-Ya Wang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli County, 35053, Taiwan
| | - Pen-Hsiu Grace Chao
- Department of Biomedical Engineering, School of Medicine and School of Engineering, National Taiwan University, Taipei, 10617, Taiwan
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2
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Piccus R, Brayson D. The nuclear envelope: LINCing tissue mechanics to genome regulation in cardiac and skeletal muscle. Biol Lett 2020; 16:20200302. [PMID: 32634376 DOI: 10.1098/rsbl.2020.0302] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Regulation of the genome is viewed through the prism of gene expression, DNA replication and DNA repair as controlled through transcription, chromatin compartmentalisation and recruitment of repair factors by enzymes such as DNA polymerases, ligases, acetylases, methylases and cyclin-dependent kinases. However, recent advances in the field of muscle cell physiology have also shown a compelling role for 'outside-in' biophysical control of genomic material through mechanotransduction. The crucial hub that transduces these biophysical signals is called the Linker of Nucleoskeleton and Cytoskeleton (LINC). This complex is embedded across the nuclear envelope, which separates the nucleus from the cytoplasm. How the LINC complex operates to mechanically regulate the many functions of DNA is becoming increasingly clear, and recent advances have provided exciting insight into how this occurs in cells from mechanically activated tissues such as skeletal and cardiac muscle. Nevertheless, there are still some notable shortcomings in our understanding of these processes and resolving these will likely help us understand how muscle diseases manifest at the level of the genome.
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Affiliation(s)
- Rachel Piccus
- Centre for Human and Applied Physiological Sciences, King's College London, London SE1 1UL, UK
| | - Daniel Brayson
- School of Cardiovascular Medicine and Sciences, King's College London, London SE5 9NU, UK.,Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
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3
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Stephens AD. Chromatin rigidity provides mechanical and genome protection. Mutat Res 2020; 821:111712. [PMID: 32590202 PMCID: PMC8186544 DOI: 10.1016/j.mrfmmm.2020.111712] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
The nucleus is the organelle in the cell that contains the genome and its associate proteins which is collectively called chromatin. New work has shown that chromatin and its compaction level, dictated largely through histone modification state, provides rigidity to protect and stabilize the nucleus. Alterations in chromatin, its mechanics, and downstream loss of nuclear shape and stability are hallmarks of human disease. Weakened nuclear mechanics and abnormal morphology have been shown to cause rupturing of the nucleus which results in nuclear dysfunction including DNA damage. Thus, the rigidity provided by chromatin to maintain nuclear mechanical stability also provides its own protection from DNA damage via compartmentalization maintenance.
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Affiliation(s)
- Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, United States.
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4
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Donnaloja F, Jacchetti E, Soncini M, Raimondi MT. Mechanosensing at the Nuclear Envelope by Nuclear Pore Complex Stretch Activation and Its Effect in Physiology and Pathology. Front Physiol 2019; 10:896. [PMID: 31354529 PMCID: PMC6640030 DOI: 10.3389/fphys.2019.00896] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/27/2019] [Indexed: 02/03/2023] Open
Abstract
Cell fate is correlated to mechanotransduction, in which forces transmitted by the cytoskeleton filaments alter the nuclear shape, affecting transcription factor import/export, cells transcription activity and chromatin distribution. There is in fact evidence that stem cells cultured in 3D environments mimicking the native niche are able to maintain their stemness or modulate their cellular function. However, the molecular and biophysical mechanisms underlying cellular mechanosensing are still largely unclear. The propagation of mechanical stimuli via a direct pathway from cell membrane integrins to SUN proteins residing in the nuclear envelop has been demonstrated, but we suggest that the cells’ fate is mainly affected by the force distribution at the nuclear envelope level, where the SUN protein transmits the stimuli via its mechanical connection to several cell structures such as chromatin, lamina and the nuclear pore complex (NPC). In this review, we analyze the NPC structure and organization, which have not as yet been fully investigated, and its plausible involvement in cell fate. NPC is a multiprotein complex that spans the nuclear envelope, and is involved in several key cellular processes such as bidirectional nucleocytoplasmic exchange, cell cycle regulation, kinetochore organization, and regulation of gene expression. As several connections between the NPC and the nuclear envelope, chromatin and other transmembrane proteins have been identified, it is reasonable to suppose that nuclear deformations can alter the NPC structure. We provide evidence that the transmission of mechanical forces may significantly affects the basket conformation via the Nup153-SUN1 connection, both altering the passage of molecules through it and influencing the state of chromatin packing. Finally, we review the known correlations between a pathological NPC structure and diseases such as cancer, autoimmune disease, aging and laminopathies.
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Affiliation(s)
- F Donnaloja
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta," Politecnico di Milano, Milan, Italy
| | - E Jacchetti
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta," Politecnico di Milano, Milan, Italy
| | - M Soncini
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy
| | - M T Raimondi
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta," Politecnico di Milano, Milan, Italy
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5
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Bikkul MU, Faragher RGA, Worthington G, Meinke P, Kerr ARW, Sammy A, Riyahi K, Horton D, Schirmer EC, Hubank M, Kill IR, Anderson RM, Slijepcevic P, Makarov E, Bridger JM. Telomere elongation through hTERT immortalization leads to chromosome repositioning in control cells and genomic instability in Hutchinson-Gilford progeria syndrome fibroblasts, expressing a novel SUN1 isoform. Genes Chromosomes Cancer 2019; 58:341-356. [PMID: 30474255 PMCID: PMC6590296 DOI: 10.1002/gcc.22711] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 11/06/2018] [Accepted: 11/22/2018] [Indexed: 02/06/2023] Open
Abstract
Immortalizing primary cells with human telomerase reverse transcriptase (hTERT) has been common practice to enable primary cells to be of extended use in the laboratory because they avoid replicative senescence. Studying exogenously expressed hTERT in cells also affords scientists models of early carcinogenesis and telomere behavior. Control and the premature ageing disease—Hutchinson‐Gilford progeria syndrome (HGPS) primary dermal fibroblasts, with and without the classical G608G mutation have been immortalized with exogenous hTERT. However, hTERT immortalization surprisingly elicits genome reorganization not only in disease cells but also in the normal control cells, such that whole chromosome territories normally located at the nuclear periphery in proliferating fibroblasts become mislocalized in the nuclear interior. This includes chromosome 18 in the control fibroblasts and both chromosomes 18 and X in HGPS cells, which physically express an isoform of the LINC complex protein SUN1 that has previously only been theoretical. Additionally, this HGPS cell line has also become genomically unstable and has a tetraploid karyotype, which could be due to the novel SUN1 isoform. Long‐term treatment with the hTERT inhibitor BIBR1532 enabled the reduction of telomere length in the immortalized cells and resulted that these mislocalized internal chromosomes to be located at the nuclear periphery, as assessed in actively proliferating cells. Taken together, these findings reveal that elongated telomeres lead to dramatic chromosome mislocalization, which can be restored with a drug treatment that results in telomere reshortening and that a novel SUN1 isoform combined with elongated telomeres leads to genomic instability. Thus, care should be taken when interpreting data from genomic studies in hTERT‐immortalized cell lines.
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Affiliation(s)
- Mehmet U. Bikkul
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | | | - Gemma Worthington
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Peter Meinke
- Friedrich‐Baur‐InstitutKlinikum der Universität MünchenMünchenGermany
- The Wellcome Trust Centre for Cell BiologyInstitute of Cell Biology, and Centre for Translational and Chemical Biology, University of EdinburghEdinburghEngland
| | - Alastair R. W. Kerr
- The Wellcome Trust Centre for Cell BiologyInstitute of Cell Biology, and Centre for Translational and Chemical Biology, University of EdinburghEdinburghEngland
| | - Aakila Sammy
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Kumars Riyahi
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Daniel Horton
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Eric C. Schirmer
- The Wellcome Trust Centre for Cell BiologyInstitute of Cell Biology, and Centre for Translational and Chemical Biology, University of EdinburghEdinburghEngland
| | - Michael Hubank
- Centre for Molecular PathologyThe Royal Marsden HospitalLondonEngland
| | - Ian R. Kill
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Rhona M. Anderson
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Predrag Slijepcevic
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Evgeny Makarov
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
| | - Joanna M. Bridger
- Genome Engineering and Maintenance NetworkInstitute for Environment, Health and Societies, Brunel University LondonUxbridgeEngland
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6
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Fal K, Asnacios A, Chabouté ME, Hamant O. Nuclear envelope: a new frontier in plant mechanosensing? Biophys Rev 2017; 9:389-403. [PMID: 28801801 PMCID: PMC5578935 DOI: 10.1007/s12551-017-0302-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/28/2017] [Indexed: 02/07/2023] Open
Abstract
In animals, it is now well established that forces applied at the cell surface are propagated through the cytoskeleton to the nucleus, leading to deformations of the nuclear structure and, potentially, to modification of gene expression. Consistently, altered nuclear mechanics has been related to many genetic disorders, such as muscular dystrophy, cardiomyopathy and progeria. In plants, the integration of mechanical signals in cell and developmental biology has also made great progress. Yet, while the link between cell wall stresses and cytoskeleton is consolidated, such cortical mechanical cues have not been integrated with the nucleoskeleton. Here, we propose to take inspiration from studies on animal nuclei to identify relevant methods amenable to probing nucleus mechanics and deformation in plant cells, with a focus on microrheology. To identify potential molecular targets, we also compare the players at the nuclear envelope, namely lamina and LINC complex, in both plant and animal nuclei. Understanding how mechanical signals are transduced to the nucleus across kingdoms will likely have essential implications in development (e.g. how mechanical cues add robustness to gene expression patterns), in the nucleoskeleton-cytoskeleton nexus (e.g. how stress is propagated in turgid/walled cells), as well as in transcriptional control, chromatin biology and epigenetics.
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Affiliation(s)
- Kateryna Fal
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342, Lyon, France
| | - Atef Asnacios
- Laboratoire Matières et Systèmes Complexes, Université Paris-Diderot and CNRS, UMR 7057, Sorbonne Paris Cité, Paris, France
| | - Marie-Edith Chabouté
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 67000, Strasbourg, France
| | - Olivier Hamant
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342, Lyon, France.
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7
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A Novel Lamin A Mutant Responsible for Congenital Muscular Dystrophy Causes Distinct Abnormalities of the Cell Nucleus. PLoS One 2017; 12:e0169189. [PMID: 28125586 PMCID: PMC5268432 DOI: 10.1371/journal.pone.0169189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 12/13/2016] [Indexed: 11/26/2022] Open
Abstract
A-type lamins, the intermediate filament proteins participating in nuclear structure and function, are encoded by LMNA. LMNA mutations can lead to laminopathies such as lipodystrophies, premature aging syndromes (progeria) and muscular dystrophies. Here, we identified a novel heterozygous LMNA p.R388P de novo mutation in a patient with a non-previously described severe phenotype comprising congenital muscular dystrophy (L-CMD) and lipodystrophy. In culture, the patient’s skin fibroblasts entered prematurely into senescence, and some nuclei showed a lamina honeycomb pattern. C2C12 myoblasts were transfected with a construct carrying the patient’s mutation; R388P-lamin A (LA) predominantly accumulated within the nucleoplasm and was depleted at the nuclear periphery, altering the anchorage of the inner nuclear membrane protein emerin and the nucleoplasmic protein LAP2-alpha. The mutant LA triggered a frequent and severe nuclear dysmorphy that occurred independently of prelamin A processing, as well as increased histone H3K9 acetylation. Nuclear dysmorphy was not significantly improved when transfected cells were treated with drugs disrupting microtubules or actin filaments or modifying the global histone acetylation pattern. Therefore, releasing any force exerted at the nuclear envelope by the cytoskeleton or chromatin did not rescue nuclear shape, in contrast to what was previously shown in Hutchinson-Gilford progeria due to other LMNA mutations. Our results point to the specific cytotoxic effect of the R388P-lamin A mutant, which is clinically related to a rare and severe multisystemic laminopathy phenotype.
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8
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Akinci B, Sankella S, Gilpin C, Ozono K, Garg A, Agarwal AK. Progeroid syndrome patients with ZMPSTE24 deficiency could benefit when treated with rapamycin and dimethylsulfoxide. Cold Spring Harb Mol Case Stud 2016; 3:a001339. [PMID: 28050601 PMCID: PMC5171694 DOI: 10.1101/mcs.a001339] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Patients with progeroid syndromes such as mandibuloacral dysplasia, type B (MADB) and restrictive dermopathy (RD) harbor mutations in zinc metalloproteinase (ZMPSTE24), an enzyme essential for posttranslational proteolysis of prelamin A to form mature lamin A. Dermal fibroblasts from these patients show increased nuclear dysmorphology and reduced proliferation; however, the efficacy of various pharmacological agents in reversing these cellular phenotypes remains unknown. In this study, fibroblasts from MADB patients exhibited marked nuclear abnormalities and reduced proliferation that improved upon treatment with rapamycin and dimethylsulfoxide but not with other agents, including farnesyl transferase inhibitors. Surprisingly, fibroblasts from an RD patient with a homozygous null mutation in ZMPSTE24, resulting in exclusive accumulation of prelamin A with no lamin A on immunoblotting of cellular lysate, exhibited few nuclear abnormalities and near-normal cellular proliferation. An unbiased proteomic analysis of the cellular lysate from RD fibroblasts revealed a lack of processing of vimentin, a cytoskeletal protein. Interestingly, the assembly of the vimentin microfibrils in MADB fibroblasts improved with rapamycin and dimethylsulfoxide. We conclude that rapamycin and dimethylsulfoxide are beneficial for improving nuclear morphology and cell proliferation of MADB fibroblasts. Data from a single RD patient's fibroblasts also suggest that prelamin A accumulation by itself might not be detrimental and requires additional alterations at the cellular level to manifest the phenotype.
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Affiliation(s)
- Baris Akinci
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Shireesha Sankella
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Christopher Gilpin
- Molecular and Cellular Imaging, Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Abhimanyu Garg
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Anil K Agarwal
- Division of Nutrition and Metabolic Diseases, Center for Human Nutrition, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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9
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SUN2 Overexpression Deforms Nuclear Shape and Inhibits HIV. J Virol 2016; 90:4199-4214. [PMID: 26865710 DOI: 10.1128/jvi.03202-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/03/2016] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED In a previous screen of putative interferon-stimulated genes, SUN2 was shown to inhibit HIV-1 infection in an uncharacterized manner. SUN2 is an inner nuclear membrane protein belonging to the linker of nucleoskeleton and cytoskeleton complex. We have analyzed here the role of SUN2 in HIV infection. We report that in contrast to what was initially thought, SUN2 is not induced by type I interferon, and that SUN2 silencing does not modulate HIV infection. However, SUN2 overexpression in cell lines and in primary monocyte-derived dendritic cells inhibits the replication of HIV but not murine leukemia virus or chikungunya virus. We identified HIV-1 and HIV-2 strains that are unaffected by SUN2, suggesting that the effect is specific to particular viral components or cofactors. Intriguingly, SUN2 overexpression induces a multilobular flower-like nuclear shape that does not impact cell viability and is similar to that of cells isolated from patients with HTLV-I-associated adult T-cell leukemia or with progeria. Nuclear shape changes and HIV inhibition both mapped to the nucleoplasmic domain of SUN2 that interacts with the nuclear lamina. This block to HIV replication occurs between reverse transcription and nuclear entry, and passaging experiments selected for a single-amino-acid change in capsid (CA) that leads to resistance to overexpressed SUN2. Furthermore, using chemical inhibition or silencing of cyclophilin A (CypA), as well as CA mutant viruses, we implicated CypA in the SUN2-imposed block to HIV infection. Our results demonstrate that SUN2 overexpression perturbs both nuclear shape and early events of HIV infection. IMPORTANCE Cells encode proteins that interfere with viral replication, a number of which have been identified in overexpression screens. SUN2 is a nuclear membrane protein that was shown to inhibit HIV infection in such a screen, but how it blocked HIV infection was not known. We show that SUN2 overexpression blocks the infection of certain strains of HIV before nuclear entry. Mutation of the viral capsid protein yielded SUN2-resistant HIV. Additionally, the inhibition of HIV infection by SUN2 involves cyclophilin A, a protein that binds the HIV capsid and directs subsequent steps of infection. We also found that SUN2 overexpression substantially changes the shape of the cell's nucleus, resulting in many flower-like nuclei. Both HIV inhibition and deformation of nuclear shape required the domain of SUN2 that interacts with the nuclear lamina. Our results demonstrate that SUN2 interferes with HIV infection and highlight novel links between nuclear shape and viral infection.
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10
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Yassine S, Escoffier J, Nahed RA, Pierre V, Karaouzene T, Ray PF, Arnoult C. Dynamics of Sun5 localization during spermatogenesis in wild type and Dpy19l2 knock-out mice indicates that Sun5 is not involved in acrosome attachment to the nuclear envelope. PLoS One 2015; 10:e0118698. [PMID: 25775128 PMCID: PMC4361733 DOI: 10.1371/journal.pone.0118698] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 01/22/2015] [Indexed: 11/19/2022] Open
Abstract
The acrosome is an organelle that is central to sperm physiology and a defective acrosome biogenesis leads to globozoospermia, a severe male infertility. The identification of the actors involved in acrosome biogenesis is therefore particularly important to decipher the molecular pathogeny of globozoospermia. We recently showed that a defect in the DPY19L2 gene is present in more than 70% of globozoospermic men and demonstrated that Dpy19l2, located in the inner nuclear membrane, is the first protein involved in the attachment of the acrosome to the nuclear envelope (NE). SUN proteins serve to link the nuclear envelope to the cytoskeleton and are therefore good candidates to participate in acrosome-nucleus attachment, potentially by interacting with DPY19L2. In order to characterize new actors of acrosomal attachment, we focused on Sun5 (also called Spag4l), which is highly expressed in male germ cells, and investigated its localization during spermatogenesis. Using immunohistochemistry and Western blot experiments in mice, we showed that Sun5 transits through different cellular compartments during meiosis. In pachytene spermatocytes, it is located in a membranous compartment different to the reticulum. In round spermatids, it progresses to the Golgi and the NE before to be located to the tail/head junction in epididymal sperm. Interestingly, we demonstrate that Sun5 is not, as initially reported, facing the acrosome but is in fact excluded from this zone. Moreover, we show that in Dpy19l2 KO spermatids, upon the detachment of the acrosome, Sun5 relocalizes to the totality of the NE suggesting that the acrosome attachment excludes Sun5 from the NE facing the acrosome. Finally, Western-blot experiments demonstrate that Sun5 is glycosylated. Overall, our work, associated with other publications, strongly suggests that the attachment of the acrosome to the nucleus does not likely depend on the formation of SUN complexes.
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Affiliation(s)
- Sandra Yassine
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
| | - Jessica Escoffier
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
| | - Roland Abi Nahed
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
| | - Virginie Pierre
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
| | - Thomas Karaouzene
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
- CHU de Grenoble, UF de Biochimie et Génétique Moléculaire, Grenoble, F-38000, France
| | - Pierre F. Ray
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
- CHU de Grenoble, UF de Biochimie et Génétique Moléculaire, Grenoble, F-38000, France
| | - Christophe Arnoult
- Université Grenoble Alpes, Grenoble, F-38000, France
- Equipe "Génétique, Epigénétique et thérapies de l’Infertilité" Institut Albert Bonniot, INSERM U823, Grenoble, F-38000, France
- * E-mail:
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11
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Chen ZJ, Wang WP, Chen YC, Wang JY, Lin WH, Tai LA, Liou GG, Yang CS, Chi YH. Dysregulated interactions between lamin A and SUN1 induce abnormalities in the nuclear envelope and endoplasmic reticulum in progeric laminopathies. J Cell Sci 2014; 127:1792-804. [PMID: 24522183 DOI: 10.1242/jcs.139683] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a human progeroid disease caused by a point mutation on the LMNA gene. We reported previously that the accumulation of the nuclear envelope protein SUN1 contributes to HGPS nuclear aberrancies. However, the mechanism by which interactions between mutant lamin A (also known as progerin or LAΔ50) and SUN1 produce HGPS cellular phenotypes requires further elucidation. Using light and electron microscopy, this study demonstrated that SUN1 contributes to progerin-elicited structural changes in the nuclear envelope and the endoplasmic reticulum (ER) network. We further identified two domains through which full-length lamin A associates with SUN1, and determined that the farnesylated cysteine within the CaaX motif of lamin A has a stronger affinity for SUN1 than does the lamin A region containing amino acids 607 to 656. Farnesylation of progerin enhanced its interaction with SUN1 and reduced SUN1 mobility, thereby promoting the aberrant recruitment of progerin to the ER membrane during postmitotic assembly of the nuclear envelope, resulting in the accumulation of SUN1 over consecutive cellular divisions. These results indicate that the dysregulated interaction of SUN1 and progerin in the ER during nuclear envelope reformation determines the progression of HGPS.
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Affiliation(s)
- Zi-Jie Chen
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Miaoli County 35053, Taiwan
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