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Perales IE, Jones SD, Piaszynski KM, Geyer PK. Developmental changes in nuclear lamina components during germ cell differentiation. Nucleus 2024; 15:2339214. [PMID: 38597409 PMCID: PMC11008544 DOI: 10.1080/19491034.2024.2339214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
The nuclear lamina (NL) changes composition for regulation of nuclear events. We investigated changes that occur in Drosophila oogenesis, revealing switches in NL composition during germ cell differentiation. Germline stem cells (GSCs) express only LamB and predominantly emerin, whereas differentiating nurse cells predominantly express LamC and emerin2. A change in LamC-specific localization also occurs, wherein phosphorylated LamC redistributes to the nuclear interior only in the oocyte, prior to transcriptional reactivation of the meiotic genome. These changes support existing concepts that LamC promotes differentiation, a premise that was tested. Remarkably ectopic LamC production in GSCs did not promote premature differentiation. Increased LamC levels in differentiating germ cells altered internal nuclear structure, increased RNA production, and reduced female fertility due to defects in eggshell formation. These studies suggest differences between Drosophila lamins are regulatory, not functional, and reveal an unexpected robustness to level changes of a major scaffolding component of the NL.
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Affiliation(s)
- Isabella E. Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Samuel D. Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | | | - Pamela K. Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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2
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Kono Y, Shimi T. Crosstalk between mitotic reassembly and repair of the nuclear envelope. Nucleus 2024; 15:2352203. [PMID: 38780365 PMCID: PMC11123513 DOI: 10.1080/19491034.2024.2352203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 05/01/2024] [Indexed: 05/25/2024] Open
Abstract
In eukaryotic cells, the nuclear envelope (NE) is a membrane partition between the nucleus and the cytoplasm to compartmentalize nuclear contents. It plays an important role in facilitating nuclear functions including transcription, DNA replication and repair. In mammalian cells, the NE breaks down and then reforms during cell division, and in interphase it is restored shortly after the NE rupture induced by mechanical force. In this way, the partitioning effect is regulated through dynamic processes throughout the cell cycle. A failure in rebuilding the NE structure triggers the mixing of nuclear and cytoplasmic contents, leading to catastrophic consequences for the nuclear functions. Whereas the precise details of molecular mechanisms for NE reformation during cell division and NE restoration in interphase are still being investigated, here, we mostly focus on mammalian cells to describe key aspects that have been identified and to discuss the crosstalk between them.
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Affiliation(s)
- Yohei Kono
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Takeshi Shimi
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kanazawa, Japan
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3
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Perales IE, Jones SD, Duan T, Geyer PK. Maintenance of germline stem cell homeostasis despite severe nuclear distortion. Dev Biol 2024; 515:139-150. [PMID: 39038593 PMCID: PMC11317214 DOI: 10.1016/j.ydbio.2024.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/17/2024] [Accepted: 07/19/2024] [Indexed: 07/24/2024]
Abstract
Stem cell loss in aging and disease is associated with nuclear deformation. Yet, how nuclear shape influences stem cell homeostasis is poorly understood. We investigated this connection using Drosophila germline stem cells, as survival of these stem cells is compromised by dysfunction of the nuclear lamina, the extensive protein network that lines the inner nuclear membrane and gives shape to the nucleus. To induce nuclear distortion in germline stem cells, we used the GAL4-UAS system to increase expression of the permanently farnesylated nuclear lamina protein, Kugelkern, a rate limiting factor for nuclear growth. We show that elevated Kugelkern levels cause severe nuclear distortion in germline stem cells, including extensive thickening and lobulation of the nuclear envelope and nuclear lamina, as well as alteration of internal nuclear compartments. Despite these changes, germline stem cell number, proliferation, and female fertility are preserved, even as females age. Collectively, these data demonstrate that disruption of nuclear architecture does not cause a failure of germline stem cell survival or homeostasis, revealing that nuclear deformation does not invariably promote stem cell loss.
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Affiliation(s)
- Isabella E Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Samuel D Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Tingting Duan
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, 52242, USA.
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4
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Li J, Jordana L, Mehsen H, Wang X, Archambault V. Nuclear reassembly defects after mitosis trigger apoptotic and p53-dependent safeguard mechanisms in Drosophila. PLoS Biol 2024; 22:e3002780. [PMID: 39186808 PMCID: PMC11379398 DOI: 10.1371/journal.pbio.3002780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 09/06/2024] [Accepted: 08/01/2024] [Indexed: 08/28/2024] Open
Abstract
In animals, mitosis involves the breakdown of the nuclear envelope and the sorting of individualized, condensed chromosomes. During mitotic exit, emerging nuclei reassemble a nuclear envelope around a single mass of interconnecting chromosomes. The molecular mechanisms of nuclear reassembly are incompletely understood. Moreover, the cellular and physiological consequences of defects in this process are largely unexplored. Here, we have characterized a mechanism essential for nuclear reassembly in Drosophila. We show that Ankle2 promotes the PP2A-dependent recruitment of BAF and Lamin at reassembling nuclei, and that failures in this mechanism result in severe nuclear defects after mitosis. We then took advantage of perturbations in this mechanism to investigate the physiological responses to nuclear reassembly defects during tissue development in vivo. Partial depletion of Ankle2, BAF, or Lamin in imaginal wing discs results in wing development defects accompanied by apoptosis. We found that blocking apoptosis strongly enhances developmental defects. Blocking p53 does not prevent apoptosis but enhances defects due to the loss of a cell cycle checkpoint. Our results suggest that apoptotic and p53-dependent responses play a crucial role in safeguarding tissue development in response to sporadic nuclear reassembly defects.
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Affiliation(s)
- Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montreal, Canada
| | - Laia Jordana
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montreal, Canada
| | - Haytham Mehsen
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montreal, Canada
| | - Xinyue Wang
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montreal, Canada
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5
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Ko BS, Han MH, Kwon MJ, Cha DG, Ji Y, Park ES, Jeon MJ, Kim S, Lee K, Choi YH, Lee J, Torras-Llort M, Yoon KJ, Lee H, Kim JK, Lee SB. Baf-mediated transcriptional regulation of teashirt is essential for the development of neural progenitor cell lineages. Exp Mol Med 2024; 56:422-440. [PMID: 38374207 PMCID: PMC10907700 DOI: 10.1038/s12276-024-01169-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 09/20/2023] [Accepted: 12/10/2023] [Indexed: 02/21/2024] Open
Abstract
Accumulating evidence hints heterochromatin anchoring to the inner nuclear membrane as an upstream regulatory process of gene expression. Given that the formation of neural progenitor cell lineages and the subsequent maintenance of postmitotic neuronal cell identity critically rely on transcriptional regulation, it seems possible that the development of neuronal cells is influenced by cell type-specific and/or context-dependent programmed regulation of heterochromatin anchoring. Here, we explored this possibility by genetically disrupting the evolutionarily conserved barrier-to-autointegration factor (Baf) in the Drosophila nervous system. Through single-cell RNA sequencing, we demonstrated that Baf knockdown induces prominent transcriptomic changes, particularly in type I neuroblasts. Among the differentially expressed genes, our genetic analyses identified teashirt (tsh), a transcription factor that interacts with beta-catenin, to be closely associated with Baf knockdown-induced phenotypes that were suppressed by the overexpression of tsh or beta-catenin. We also found that Baf and tsh colocalized in a region adjacent to heterochromatin in type I NBs. Notably, the subnuclear localization pattern remained unchanged when one of these two proteins was knocked down, indicating that both proteins contribute to the anchoring of heterochromatin to the inner nuclear membrane. Overall, this study reveals that the Baf-mediated transcriptional regulation of teashirt is a novel molecular mechanism that regulates the development of neural progenitor cell lineages.
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Affiliation(s)
- Byung Su Ko
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Myeong Hoon Han
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Min Jee Kwon
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Dong Gon Cha
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Yuri Ji
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Eun Seo Park
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Min Jae Jeon
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Somi Kim
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Kyeongho Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu, 42988, Republic of Korea
| | - Yoon Ha Choi
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Jusung Lee
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | | | - Ki-Jun Yoon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hyosang Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
- Convergence Research Advanced Centre for Olfaction, DGIST, Daegu, 42988, Republic of Korea
| | - Jong Kyoung Kim
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea.
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
| | - Sung Bae Lee
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea.
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6
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Buxboim A, Kronenberg-Tenga R, Salajkova S, Avidan N, Shahak H, Thurston A, Medalia O. Scaffold, mechanics and functions of nuclear lamins. FEBS Lett 2023; 597:2791-2805. [PMID: 37813648 DOI: 10.1002/1873-3468.14750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/05/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023]
Abstract
Nuclear lamins are type-V intermediate filaments that are involved in many nuclear processes. In mammals, A- and B-type lamins assemble into separate physical meshwork underneath the inner nuclear membrane, the nuclear lamina, with some residual fraction localized within the nucleoplasm. Lamins are the major part of the nucleoskeleton, providing mechanical strength and flexibility to protect the genome and allow nuclear deformability, while also contributing to gene regulation via interactions with chromatin. While lamins are the evolutionary ancestors of all intermediate filament family proteins, their ultimate filamentous assembly is markedly different from their cytoplasmic counterparts. Interestingly, hundreds of genetic mutations in the lamina proteins have been causally linked with a broad range of human pathologies, termed laminopathies. These include muscular, neurological and metabolic disorders, as well as premature aging diseases. Recent technological advances have contributed to resolving the filamentous structure of lamins and the corresponding lamina organization. In this review, we revisit the multiscale lamin organization and discuss its implications on nuclear mechanics and chromatin organization within lamina-associated domains.
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Affiliation(s)
- Amnon Buxboim
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Sarka Salajkova
- Department of Biochemistry, University of Zurich, Switzerland
| | - Nili Avidan
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Hen Shahak
- The Rachel and Selim Benin School of Computer Science and Engineering and The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Alice Thurston
- Department of Biochemistry, University of Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Switzerland
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7
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Marcelot A, Rodriguez-Tirado F, Cuniasse P, Joiner ML, Miron S, Soshnev AA, Fang M, Pufall MA, Mathews KD, Moore SA, Zinn-Justin S, Geyer PK. A De Novo Sequence Variant in Barrier-to-Autointegration Factor Is Associated with Dominant Motor Neuronopathy. Cells 2023; 12:847. [PMID: 36980188 PMCID: PMC10099716 DOI: 10.3390/cells12060847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/23/2023] [Accepted: 02/26/2023] [Indexed: 03/12/2023] Open
Abstract
Barrier-to-autointegration factor (BAF) is an essential component of the nuclear lamina. Encoded by BANF1, this DNA binding protein contributes to the regulation of gene expression, cell cycle progression, and nuclear integrity. A rare recessive BAF variant, Ala12Thr, causes the premature aging syndrome, Néstor-Guillermo progeria syndrome (NGPS). Here, we report the first dominant pathogenic BAF variant, Gly16Arg, identified in a patient presenting with progressive neuromuscular weakness. Although disease variants carry nearby amino acid substitutions, cellular and biochemical properties are distinct. In contrast to NGPS, Gly16Arg patient fibroblasts show modest changes in nuclear lamina structure and increases in repressive marks associated with heterochromatin. Structural studies reveal that the Gly16Arg substitution introduces a salt bridge between BAF monomers, reducing the conformation ensemble available to BAF. We show that this structural change increases the double-stranded DNA binding affinity of BAF Gly16Arg. Together, our findings suggest that BAF Gly16Arg has an increased chromatin occupancy that leads to epigenetic changes and impacts nuclear functions. These observations provide a new example of how a missense mutation can change a protein conformational equilibrium to cause a dominant disease and extend our understanding of mechanisms by which BAF function impacts human health.
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Affiliation(s)
- Agathe Marcelot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (A.M.); (P.C.); (S.M.)
- Expression Génétique Microbienne, UMR 8261, CNRS, Institut de Biologie Physico-Chimique (IBPC), Université Paris Cité, 75005 Paris, France
| | - Felipe Rodriguez-Tirado
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (F.R.-T.); (M.-l.J.); (M.F.); (M.A.P.)
| | - Philippe Cuniasse
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (A.M.); (P.C.); (S.M.)
| | - Mei-ling Joiner
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (F.R.-T.); (M.-l.J.); (M.F.); (M.A.P.)
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (A.M.); (P.C.); (S.M.)
| | - Alexey A. Soshnev
- Department of Neuroscience, Developmental and Regenerative Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA;
| | - Mimi Fang
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (F.R.-T.); (M.-l.J.); (M.F.); (M.A.P.)
| | - Miles A. Pufall
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (F.R.-T.); (M.-l.J.); (M.F.); (M.A.P.)
| | - Katherine D. Mathews
- Department of Pediatrics and Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;
- Wellstone Muscular Dystrophy Specialized Research Center, Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Steven A. Moore
- Wellstone Muscular Dystrophy Specialized Research Center, Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA;
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France; (A.M.); (P.C.); (S.M.)
| | - Pamela K. Geyer
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (F.R.-T.); (M.-l.J.); (M.F.); (M.A.P.)
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8
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Mendaluk A, Caussinus E, Boutros M, Lehner CF. A genome-wide RNAi screen for genes important for proliferation of cultured Drosophila cells at low temperature identifies the Ball/VRK protein kinase. Chromosoma 2023; 132:31-53. [PMID: 36746786 PMCID: PMC9981717 DOI: 10.1007/s00412-023-00787-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023]
Abstract
A change in ambient temperature is predicted to disrupt cellular homeostasis by affecting all cellular processes in an albeit non-uniform manner. Diffusion is generally less temperature-sensitive than enzymes, for example, and each enzyme has a characteristic individual temperature profile. The actual effects of temperature variation on cells are still poorly understood at the molecular level. Towards an improved understanding, we have performed a genome-wide RNA interference screen with S2R + cells. This Drosophila cell line proliferates over a temperature range comparable to that tolerated by the parental ectothermic organism. Based on effects on cell counts and cell cycle profile after knockdown at 27 and 17 °C, respectively, genes were identified with an apparent greater physiological significance at one or the other temperature. While 27 °C is close to the temperature optimum, the substantially lower 17 °C was chosen to identify genes important at low temperatures, which have received less attention compared to the heat shock response. Among a substantial number of screen hits, we validated a set successfully in cell culture and selected ballchen for further evaluation in the organism. This gene encodes the conserved metazoan VRK protein kinase that is crucial for the release of chromosomes from the nuclear envelope during mitosis. Our analyses in early embryos and larval wing imaginal discs confirmed a higher requirement for ballchen function at temperatures below the optimum. Overall, our experiments validate the genome-wide screen as a basis for future characterizations of genes with increased physiological significance at the lower end of the readily tolerated temperature range.
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Affiliation(s)
- Anna Mendaluk
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Emmanuel Caussinus
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland
| | - Michael Boutros
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Heidelberg University, BioQuant, Heidelberg, Germany
| | - Christian F Lehner
- Department of Molecular Life Science (DMLS), University of Zurich, Zurich, Switzerland.
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9
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Duan T, Thyagarajan S, Amoiroglou A, Rogers GC, Geyer PK. Analysis of a rare progeria variant of Barrier-to-autointegration factor in Drosophila connects centromere function to tissue homeostasis. Cell Mol Life Sci 2023; 80:73. [PMID: 36842139 PMCID: PMC9968693 DOI: 10.1007/s00018-023-04721-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/27/2023]
Abstract
Barrier-to-autointegration factor (BAF/BANF) is a nuclear lamina protein essential for nuclear integrity, chromatin structure, and genome stability. Whereas complete loss of BAF causes lethality in multiple organisms, the A12T missense mutation of the BANF1 gene in humans causes a premature aging syndrome, called Néstor-Guillermo Progeria Syndrome (NGPS). Here, we report the first in vivo animal investigation of progeroid BAF, using CRISPR editing to introduce the NGPS mutation into the endogenous Drosophila baf gene. Progeroid BAF adults are born at expected frequencies, demonstrating that this BAF variant retains some function. However, tissue homeostasis is affected, supported by studies of the ovary, a tissue that depends upon BAF for stem cell survival and continuous oocyte production. We find that progeroid BAF causes defects in germline stem cell mitosis that delay anaphase progression and compromise chromosome segregation. We link these defects to decreased recruitment of centromeric proteins of the kinetochore, indicating dysfunction of cenBAF, a localized pool of dephosphorylated BAF produced by Protein Phosphatase PP4. We show that DNA damage increases in progenitor germ cells, which causes germ cell death due to activation of the DNA damage transducer kinase Chk2. Mitotic defects appear widespread, as aberrant chromosome segregation and increased apoptosis occur in another tissue. Together, these data highlight the importance of BAF in establishing centromeric structures critical for mitosis. Further, these studies link defects in cenBAF function to activation of a checkpoint that depletes progenitor reserves critical for tissue homeostasis, aligning with phenotypes of NGPS patients.
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Affiliation(s)
- Tingting Duan
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, 15232, USA
| | - Srikantha Thyagarajan
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA
| | - Anastasia Amoiroglou
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85724, USA
| | - Gregory C Rogers
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, 85724, USA
| | - Pamela K Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, 3135E MERF, Iowa City, IA, 52242, USA.
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10
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Lunin SM, Novoselova EG, Glushkova OV, Parfenyuk SB, Novoselova TV, Khrenov MO. Cell Senescence and Central Regulators of Immune Response. Int J Mol Sci 2022; 23:ijms23084109. [PMID: 35456927 PMCID: PMC9028919 DOI: 10.3390/ijms23084109] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/04/2022] [Accepted: 04/06/2022] [Indexed: 12/13/2022] Open
Abstract
Pathways regulating cell senescence and cell cycle underlie many processes associated with ageing and age-related pathologies, and they also mediate cellular responses to exposure to stressors. Meanwhile, there are central mechanisms of the regulation of stress responses that induce/enhance or weaken the response of the whole organism, such as hormones of the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic and parasympathetic systems, thymic hormones, and the pineal hormone melatonin. Although there are many analyses considering relationships between the HPA axis and organism ageing, we found no systematic analyses of relationships between the neuroendocrine regulators of stress and inflammation and intracellular mechanisms controlling cell cycle, senescence, and apoptosis. Here, we provide a review of the effects of neuroendocrine regulators on these mechanisms. Our analysis allowed us to postulate a multilevel system of central regulators involving neurotransmitters, glucocorticoids, melatonin, and the thymic hormones. This system finely regulates the cell cycle and metabolic/catabolic processes depending on the level of systemic stress, stage of stress response, and energy capabilities of the body, shifting the balance between cell cycle progression, cell cycle stopping, senescence, and apoptosis. These processes and levels of regulation should be considered when studying the mechanisms of ageing and the proliferation on the level of the whole organism.
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11
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Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
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Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
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12
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Rose M, Bai B, Tang M, Cheong CM, Beard S, Burgess JT, Adams MN, O'Byrne KJ, Richard DJ, Gandhi NS, Bolderson E. The Impact of Rare Human Variants on Barrier-To-Auto-Integration Factor 1 (Banf1) Structure and Function. Front Cell Dev Biol 2021; 9:775441. [PMID: 34820387 PMCID: PMC8606531 DOI: 10.3389/fcell.2021.775441] [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] [Received: 09/14/2021] [Accepted: 10/18/2021] [Indexed: 11/23/2022] Open
Abstract
Barrier-to-Autointegration Factor 1 (Banf1/BAF) is a critical component of the nuclear envelope and is involved in the maintenance of chromatin structure and genome stability. Banf1 is a small DNA binding protein that is conserved amongst multicellular eukaryotes. Banf1 functions as a dimer, and binds non-specifically to the phosphate backbone of DNA, compacting the DNA in a looping process. The loss of Banf1 results in loss of nuclear envelope integrity and aberrant chromatin organisation. Significantly, mutations in Banf1 are associated with the severe premature ageing syndrome, Néstor–Guillermo Progeria Syndrome. Previously, rare human variants of Banf1 have been identified, however the impact of these variants on Banf1 function has not been explored. Here, using in silico modelling, biophysical and cell-based approaches, we investigate the effect of rare human variants on Banf1 structure and function. We show that these variants do not significantly alter the secondary structure of Banf1, but several single amino acid variants in the N- and C-terminus of Banf1 impact upon the DNA binding ability of Banf1, without altering Banf1 localisation or nuclear integrity. The functional characterisation of these variants provides further insight into Banf1 structure and function and may aid future studies examining the potential impact of Banf1 function on nuclear structure and human health.
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Affiliation(s)
- Maddison Rose
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Bond Bai
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Ming Tang
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Chee Man Cheong
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Sam Beard
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Joshua T Burgess
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Mark N Adams
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Kenneth J O'Byrne
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Woolloongabba, QLD, Australia
| | - Derek J Richard
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Neha S Gandhi
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia.,School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia
| | - Emma Bolderson
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
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13
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Chen NY, Kim PH, Tu Y, Yang Y, Heizer PJ, Young SG, Fong LG. Increased expression of LAP2β eliminates nuclear membrane ruptures in nuclear lamin-deficient neurons and fibroblasts. Proc Natl Acad Sci U S A 2021; 118:e2107770118. [PMID: 34161290 PMCID: PMC8237679 DOI: 10.1073/pnas.2107770118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects or deficiencies in nuclear lamins cause pathology in many cell types, and recent studies have implicated nuclear membrane (NM) ruptures as a cause of cell toxicity. We previously observed NM ruptures and progressive cell death in the developing brain of lamin B1-deficient mouse embryos. We also observed frequent NM ruptures and DNA damage in nuclear lamin-deficient fibroblasts. Factors modulating susceptibility to NM ruptures remain unclear, but we noted low levels of LAP2β, a chromatin-binding inner NM protein, in fibroblasts with NM ruptures. Here, we explored the apparent link between LAP2β and NM ruptures in nuclear lamin-deficient neurons and fibroblasts, and we tested whether manipulating LAP2β expression levels would alter NM rupture frequency. In cortical plate neurons of lamin B1-deficient embryos, we observed a strong correlation between low LAP2β levels and NM ruptures. We also found low LAP2β levels and frequent NM ruptures in neurons of cultured Lmnb1-/- neurospheres. Reducing LAP2β expression in Lmnb1-/- neurons with an siRNA markedly increased the NM rupture frequency (without affecting NM rupture duration), whereas increased LAP2β expression eliminated NM ruptures and reduced DNA damage. Consistent findings were observed in nuclear lamin-deficient fibroblasts. Reduced LAP2β expression increased NM ruptures, whereas increased LAP2β expression virtually abolished NM ruptures. Increased LAP2β expression nearly abolished NM ruptures in cells subjected to mechanical stress (an intervention that increases NM ruptures). Our studies showed that increasing LAP2β expression bolsters NM integrity in nuclear lamin-deficient cells and markedly reduces NM rupture frequency.
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Affiliation(s)
- Natalie Y Chen
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Ye Yang
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Patrick J Heizer
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, CA 90095;
- Department of Human Genetics, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, CA 90095
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, CA 90095;
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14
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Borah S, Thaller DJ, Hakhverdyan Z, Rodriguez EC, Isenhour AW, Rout MP, King MC, Lusk CP. Heh2/Man1 may be an evolutionarily conserved sensor of NPC assembly state. Mol Biol Cell 2021; 32:1359-1373. [PMID: 34010011 PMCID: PMC8694041 DOI: 10.1091/mbc.e20-09-0584] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Integral membrane proteins of the Lap2-emerin-MAN1 (LEM) family have emerged as important components of the inner nuclear membrane (INM) required for the functional and physical integrity of the nuclear envelope. However, like many INM proteins, there is limited understanding of the biochemical interaction networks that enable LEM protein function. Here, we show that Heh2/Man1 can interact with major scaffold components of the nuclear pore complex (NPC), specifically the inner ring complex (IRC), in evolutionarily distant yeasts. Although an N-terminal domain is required for Heh2 targeting to the INM, we demonstrate that more stable interactions with the NPC are mediated by a C-terminal winged helix (WH) domain, thus decoupling INM targeting and NPC binding. Inhibiting Heh2's interactions with the NPC by deletion of the Heh2 WH domain leads to NPC clustering. Interestingly, Heh2's association with NPCs can also be disrupted by knocking out several outer ring nucleoporins. Thus, Heh2's interaction with NPCs depends on the structural integrity of both major NPC scaffold complexes. We propose a model in which Heh2 acts as a sensor of NPC assembly state, which may be important for NPC quality control mechanisms and the segregation of NPCs during cell division.
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Affiliation(s)
- Sapan Borah
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - David J Thaller
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | | - Elisa C Rodriguez
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - Anthony W Isenhour
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | | | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
| | - C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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15
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Wong X, Cutler JA, Hoskins VE, Gordon M, Madugundu AK, Pandey A, Reddy KL. Mapping the micro-proteome of the nuclear lamina and lamina-associated domains. Life Sci Alliance 2021; 4:e202000774. [PMID: 33758005 PMCID: PMC8008952 DOI: 10.26508/lsa.202000774] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/13/2023] Open
Abstract
The nuclear lamina is a proteinaceous network of filaments that provide both structural and gene regulatory functions by tethering proteins and large domains of DNA, the so-called lamina-associated domains (LADs), to the periphery of the nucleus. LADs are a large fraction of the mammalian genome that are repressed, in part, by their association to the nuclear periphery. The genesis and maintenance of LADs is poorly understood as are the proteins that participate in these functions. In an effort to identify proteins that reside at the nuclear periphery and potentially interact with LADs, we have taken a two-pronged approach. First, we have undertaken an interactome analysis of the inner nuclear membrane bound LAP2β to further characterize the nuclear lamina proteome. To accomplish this, we have leveraged the BioID system, which previously has been successfully used to characterize the nuclear lamina proteome. Second, we have established a system to identify proteins that bind to LADs by developing a chromatin-directed BioID system. We combined the BioID system with the m6A-tracer system which binds to LADs in live cells to identify both LAD proximal and nuclear lamina proteins. In combining these datasets, we have further characterized the protein network at the nuclear lamina, identified putative LAD proximal proteins and found several proteins that appear to interface with both micro-proteomes. Importantly, several proteins essential for LAD function, including heterochromatin regulating proteins related to H3K9 methylation, were identified in this study.
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Affiliation(s)
- Xianrong Wong
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Laboratory of Developmental and Regenerative Biology, Institute of Medical Biology, Agency for Science, Technology and Research (A∗STAR), Immunos, Singapore
| | - Jevon A Cutler
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Victoria E Hoskins
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Molly Gordon
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anil K Madugundu
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
| | - Akhilesh Pandey
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
- Manipal Academy of Higher Education (MAHE), Manipal, India
- Departments of Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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16
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Torras-Llort M, Medina-Giró S, Escudero-Ferruz P, Lipinszki Z, Moreno-Moreno O, Karman Z, Przewloka MR, Azorín F. A fraction of barrier-to-autointegration factor (BAF) associates with centromeres and controls mitosis progression. Commun Biol 2020; 3:454. [PMID: 32814801 PMCID: PMC7438335 DOI: 10.1038/s42003-020-01182-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 07/30/2020] [Indexed: 01/01/2023] Open
Abstract
Barrier-to-Autointegration Factor (BAF) is a conserved nuclear envelope (NE) component that binds chromatin and helps its anchoring to the NE. Cycles of phosphorylation and dephosphorylation control BAF function. Entering mitosis, phosphorylation releases BAF from chromatin and facilitates NE-disassembly. At mitotic exit, PP2A-mediated dephosphorylation restores chromatin binding and nucleates NE-reassembly. Here, we show that in Drosophila a small fraction of BAF (cenBAF) associates with centromeres. We also find that PP4 phosphatase, which is recruited to centromeres by CENP-C, prevents phosphorylation and release of cenBAF during mitosis. cenBAF is necessary for proper centromere assembly and accurate chromosome segregation, being critical for mitosis progression. Disrupting cenBAF localization prevents PP2A inactivation in mitosis compromising global BAF phosphorylation, which in turn leads to its persistent association with chromatin, delays anaphase onset and causes NE defects. These results suggest that, together with PP4 and CENP-C, cenBAF forms a centromere-based mechanism that controls chromosome segregation and mitosis progression.
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Affiliation(s)
- Mònica Torras-Llort
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain.
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Sònia Medina-Giró
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Paula Escudero-Ferruz
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zoltan Lipinszki
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation and Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Olga Moreno-Moreno
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zoltan Karman
- MTA SZBK Lendület Laboratory of Cell Cycle Regulation and Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Marcin R Przewloka
- School of Biological Sciences, Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Fernando Azorín
- Institute of Molecular Biology of Barcelona, CSIC, Barcelona, Spain.
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain.
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17
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Sears RM, Roux KJ. Diverse cellular functions of barrier-to-autointegration factor and its roles in disease. J Cell Sci 2020; 133:133/16/jcs246546. [PMID: 32817163 DOI: 10.1242/jcs.246546] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Barrier-to-autointegration factor (BAF; encoded by BANF1) is a small highly conserved, ubiquitous and self-associating protein that coordinates with numerous binding partners to accomplish several key cellular processes. By interacting with double-stranded DNA, histones and various other nuclear proteins, including those enriched at the nuclear envelope, BAF appears to be essential for replicating cells to protect the genome and enable cell division. Cellular processes, such as innate immunity, post-mitotic nuclear reformation, repair of interphase nuclear envelope rupture, genomic regulation, and the DNA damage and repair response have all been shown to depend on BAF. This Review focuses on the regulation of the numerous interactions of BAF, which underlie the mechanisms by which BAF accomplishes its essential cellular functions. We will also discuss how perturbation of BAF function may contribute to human disease.
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Affiliation(s)
- Rhiannon M Sears
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA.,Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Kyle J Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA .,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57069, USA
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18
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Lunin S, Khrenov M, Glushkova O, Parfenyuk S, Novoselova T, Novoselova E. Precursors of thymic peptides as stress sensors. Expert Opin Biol Ther 2020; 20:1461-1475. [PMID: 32700610 DOI: 10.1080/14712598.2020.1800636] [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] [Indexed: 01/20/2023]
Abstract
INTRODUCTION A large volume of data indicates that the known thymic hormones, thymulin, thymopoietin, thymosin-α, thymosin-β, and thymic humoral factor-y2, exhibit different spectra of activities. Although large in volume, available data are rather fragmented, resulting in a lack of understanding of the role played by thymic hormones in immune homeostasis. AREA COVERED Existing data compartmentalizes the effect of thymic peptides into 2 categories: influence on immune cells and interconnection with neuroendocrine systems. The current study draws attention to a third aspect of the thymic peptide effect that has not been clarified yet, wherein ubiquitous and highly abundant intranuclear precursors of so called 'thymic peptides' play a fundamental role in all somatic cells. EXPERT OPINION Our analysis indicated that, under certain stress-related conditions, these precursors are cleaved to form immunologically active peptides that rapidly leave the nucleus and intracellular spaces, to send 'distress signals' to the immune system, thereby acting as stress sensors. We propose that these peptides may form a link between somatic cells and immune as well as neuroendocrine systems. This model may provide a better understanding of the mechanisms underlying immune homeostasis, leading thereby to the development of new therapeutic regimes utilizing the characteristics of thymic peptides.
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Affiliation(s)
- Sergey Lunin
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Maxim Khrenov
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Olga Glushkova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Svetlana Parfenyuk
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - Tatyana Novoselova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
| | - E Novoselova
- Laboratory of Reception Mechanisms, Institute of Cell Biophysics of the Russian Academy of Sciences, PSCBR RAS , Pushchino, Russia
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19
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Zhou H, Zhang L, Tu H. Downregulation of thymopoietin by miR-139-5p suppresses cell proliferation and induces cell cycle arrest/apoptosis in pancreatic ductal adenocarcinoma. Oncol Lett 2019; 18:3443-3452. [PMID: 31516562 PMCID: PMC6733013 DOI: 10.3892/ol.2019.10679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 04/16/2019] [Indexed: 12/01/2022] Open
Abstract
MicroRNAs (miRNAs) serve a pivotal role in tumor development and progression, in which miRNA (miR)-139-5p functions as a tumor suppressor. However, the functions and mechanisms of miR-139-5p in pancreatic ductal adenocarcinoma (PDAC) remain unclear. In the present study, it was found that miR-139-5p was markedly decreased in PDAC tissues and cell lines. Noticeably, thymopoietin (TMPO) was predicted and confirmed as a direct target of miR-139-5p using a luciferase reporter system. The expression level of miR-139-5p was inversely associated with the expression of TMPO in PDAC specimens. A series of gain-of-function assays elucidated that the overexpression of miR-139-5p suppressed cell proliferation, and induced cell cycle arrest and cell apoptosis, determined with a Cell Counting Kit-8, colony formation assays and flow cytometry, respectively. Furthermore, the re-expression of TMPO eliminated the effects of miR-139-5p on cell proliferation, cell cycle progression and apoptosis. In summary, these findings demonstrated that miR-139-5p may be a tumor suppressor in PDAC, which may be useful in developing promising therapies for PDAC.
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Affiliation(s)
- Huadong Zhou
- Department of Hepatobiliary Pancreatic Surgery, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Linfei Zhang
- Department of Hepatobiliary Pancreatic Surgery, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Huahua Tu
- Department of Hepatobiliary Pancreatic Surgery, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
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20
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Nuclear formation induced by DNA-conjugated beads in living fertilised mouse egg. Sci Rep 2019; 9:8461. [PMID: 31186495 PMCID: PMC6560220 DOI: 10.1038/s41598-019-44941-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/17/2019] [Indexed: 11/08/2022] Open
Abstract
Reformation of a functional nucleus at the end of mitosis is crucial for normal cellular activity. Reconstitution approaches using artificial beads in frog egg extracts have clarified the molecules required for nuclear formation in vitro. However, the spatiotemporal regulation of these components, which is required for the formation of a functional nucleus in living embryos, remains unknown. Here we demonstrate that exogenous DNA introduced in the form of DNA-conjugated beads induces the assembly of an artificial nucleus in living mouse cleavage-stage embryos. Live-cell imaging and immunofluorescence studies revealed that core histones and regulator of chromosome condensation 1 (RCC1) assembled on the DNA, suggesting that nucleosomes were formed. Electron microscopy showed that double-membrane structures, partly extended from annulate lamellae, formed around the beads. Nuclear pore complex-like structures indistinguishable from those of native nuclei were also formed, suggesting that this membranous structure resembled the normal nuclear envelope (NE). However, the reconstituted NE had no nuclear import activity, probably because of the absence of Ras-related nuclear protein (Ran). Thus, DNA is necessary for NE reassembly in mouse embryos but is insufficient to form a functional nucleus. This approach provides a new tool to examine factors of interest and their spatiotemporal regulation in nuclear formation.
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21
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Dubińska-Magiera M, Kozioł K, Machowska M, Piekarowicz K, Filipczak D, Rzepecki R. Emerin Is Required for Proper Nucleus Reassembly after Mitosis: Implications for New Pathogenetic Mechanisms for Laminopathies Detected in EDMD1 Patients. Cells 2019; 8:E240. [PMID: 30871242 PMCID: PMC6468536 DOI: 10.3390/cells8030240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/26/2019] [Accepted: 03/05/2019] [Indexed: 12/29/2022] Open
Abstract
Emerin is an essential LEM (LAP2, Emerin, MAN1) domain protein in metazoans and an integral membrane protein associated with inner and outer nuclear membranes. Mutations in the human EMD gene coding for emerin result in the rare genetic disorder: Emery⁻Dreifuss muscular dystrophy type 1 (EDMD1). This disease belongs to a broader group called laminopathies-a heterogeneous group of rare genetic disorders affecting tissues of mesodermal origin. EDMD1 phenotype is characterized by progressive muscle wasting, contractures of the elbow and Achilles tendons, and cardiac conduction defects. Emerin is involved in many cellular and intranuclear processes through interactions with several partners: lamins; barrier-to-autointegration factor (BAF), β-catenin, actin, and tubulin. Our study demonstrates the presence of the emerin fraction which associates with mitotic spindle microtubules and centrosomes during mitosis and colocalizes during early mitosis with lamin A/C, BAF, and membranes at the mitotic spindle. Transfection studies with cells expressing EGFP-emerin protein demonstrate that the emerin fusion protein fraction also localizes to centrosomes and mitotic spindle microtubules during mitosis. Transient expression of emerin deletion mutants revealed that the resulting phenotypes vary and are mutant dependent. The most frequent phenotypes include aberrant nuclear shape, tubulin network mislocalization, aberrant mitosis, and mislocalization of centrosomes. Emerin deletion mutants demonstrated different chromatin binding capacities in an in vitro nuclear assembly assay and chromatin-binding properties correlated with the strength of phenotypic alteration in transfected cells. Aberrant tubulin staining and microtubule network phenotype appearance depended on the presence of the tubulin binding region in the expressed deletion mutants. We believe that the association with tubulin might help to "deliver" emerin and associated membranes to decondensing chromatin. Preliminary analyses of cells from Polish patients with EDMD1 revealed that for several mutations thought to be null for emerin protein, a truncated emerin protein was present. We infer that the EDMD1 phenotype may be strengthened by the toxicity of truncated emerin expressed in patients with certain nonsense mutations in EMD.
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Affiliation(s)
- Magda Dubińska-Magiera
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wroclaw, Sienkiewicza 21, 50-335 Wroclaw, Poland.
| | - Katarzyna Kozioł
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Magdalena Machowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Katarzyna Piekarowicz
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Daria Filipczak
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Ryszard Rzepecki
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland.
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22
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Brull A, Morales Rodriguez B, Bonne G, Muchir A, Bertrand AT. The Pathogenesis and Therapies of Striated Muscle Laminopathies. Front Physiol 2018; 9:1533. [PMID: 30425656 PMCID: PMC6218675 DOI: 10.3389/fphys.2018.01533] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/11/2018] [Indexed: 01/04/2023] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a genetic condition characterized by early contractures, skeletal muscle weakness, and cardiomyopathy. During the last 20 years, various genetic approaches led to the identification of causal genes of EDMD and related disorders, all encoding nuclear envelope proteins. By their respective localization either at the inner nuclear membrane or the outer nuclear membrane, these proteins interact with each other and establish a connection between the nucleus and the cytoskeleton. Beside this physical link, these proteins are also involved in mechanotransduction, responding to environmental cues, such as increased tension of the cytoskeleton, by the activation or repression of specific sets of genes. This ability of cells to adapt to environmental conditions is altered in EDMD. Increased knowledge on the pathophysiology of EDMD has led to the development of drug or gene therapies that have been tested on mouse models. This review proposed an overview of the functions played by the different proteins involved in EDMD and related disorders and the current therapeutic approaches tested so far.
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Affiliation(s)
- Astrid Brull
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France.,Sanofi R&D, Chilly Mazarin, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
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Li J, Hu B, Fang L, Gao Y, Shi S, He H, Liu X, Yuan C. Barrier-to-autointegration factor 1: A novel biomarker for gastric cancer. Oncol Lett 2018; 16:6488-6494. [PMID: 30405787 PMCID: PMC6202538 DOI: 10.3892/ol.2018.9432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 06/26/2018] [Indexed: 12/30/2022] Open
Abstract
China is a country with a high incidence of gastric cancer (GC), where the GC incidence and the resultant mortality rates account for 50% of those worldwide. Surgical resection remains the primary treatment for GC. However, postoperative patients have a poor prognosis as the majority of patients present with metastases at the time of diagnosis. Therefore, the identification of novel treatment targets is required. The present study aimed to determine the effects of barrier-to-autointegration factor 1 (BANF1) on the clinical features and prognosis of GC, which may aid in discovering a novel tumor diagnostic biomarker and treatment target. The BANF1 gene expression profiles for normal and gastric tumor tissues were downloaded from the Gene Expression Omnibus GSE54129 data set to analyse the expression of BANF1 at the mRNA levels. Then, online survival analysis was performed using the GC database with the Kaplan-Meier Plotter (http://kmplot.com/analysis/) data. To examine the association between BANF1 and clinical features and prognosis, 132 postoperative GC pathological specimens were collected for immunohistochemical analyses. In the GSE54129 data sets, BANF1 expression at the mRNA level was significantly higher in the tumor tissue compared with that in the normal tissue. The same result was obtained in following the immunohistochemical analyses. In addition, BANF1 expression was associated with the patient age, tumor differentiation and infiltration depth. The survival time of BANF1 high-expression patients was shorter compared with that of the low-expression patients, and tumor differentiation status and tumor node metastasis stage were independent prognostic factors of the overall survival of patients with GC. The results of the present study suggest that BANF1 is associated with the clinical features and prognosis of GC. It may be a novel indicator of tumor prognosis and a potential therapeutic target for GC.
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Affiliation(s)
- Junjun Li
- Department of Oncology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Bingbing Hu
- Department of Infectious Diseases, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan 453000, P.R. China
| | - Lei Fang
- Department of Pathology and Pathophysiology, Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Yang Gao
- Department of Oncology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Shuai Shi
- Department of Pathology and Pathophysiology, Jinzhou Medical University, Jinzhou, Liaoning 121001, P.R. China
| | - Haoyu He
- Department of Oncology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Xiaomei Liu
- Department of Oncology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
| | - Caijun Yuan
- Department of Oncology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, Liaoning 121000, P.R. China
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Pałka M, Tomczak A, Grabowska K, Machowska M, Piekarowicz K, Rzepecka D, Rzepecki R. Laminopathies: what can humans learn from fruit flies. Cell Mol Biol Lett 2018; 23:32. [PMID: 30002683 PMCID: PMC6034310 DOI: 10.1186/s11658-018-0093-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/05/2018] [Indexed: 01/01/2023] Open
Abstract
Lamin proteins are type V intermediate filament proteins (IFs) located inside the cell nucleus. They are evolutionarily conserved and have similar domain organization and properties to cytoplasmic IFs. Lamins provide a skeletal network for chromatin, the nuclear envelope, nuclear pore complexes and the entire nucleus. They are also responsible for proper connections between the karyoskeleton and structural elements in the cytoplasm: actin and the microtubule and cytoplasmic IF networks. Lamins affect transcription and splicing either directly or indirectly. Translocation of active genes into the close proximity of nuclear lamina is thought to result in their transcriptional silencing. Mutations in genes coding for lamins and interacting proteins in humans result in various genetic disorders, called laminopathies. Human genes coding for A-type lamin (LMNA) are the most frequently mutated. The resulting phenotypes include muscle, cardiac, neuronal, lipodystrophic and metabolic pathologies, early aging phenotypes, and combined complex phenotypes. The Drosophila melanogaster genome codes for lamin B-type (lamin Dm), lamin A-type (lamin C), and for LEM-domain proteins, BAF, LINC-complex proteins and all typical nuclear proteins. The fruit fly system is simpler than the vertebrate one since in flies there is only single lamin B-type and single lamin A-type protein, as opposed to the complex system of B- and A-type lamins in Danio, Xenopus and Mus musculus. This offers a unique opportunity to study laminopathies. Applying genetic tools based on Gal4 and in vitro nuclear assembly system to the fruit fly model may successfully advance knowledge of laminopathies. Here, we review studies of the laminopathies in the fly model system.
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Affiliation(s)
- Marta Pałka
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Aleksandra Tomczak
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Katarzyna Grabowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Magdalena Machowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Katarzyna Piekarowicz
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Dorota Rzepecka
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Ryszard Rzepecki
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
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Abstract
PURPOSE OF REVIEW Nuclear envelope links to a wide range of disorders, including several myopathies and neuropathies over the past 2 decades, has spurred research leading to a completely changed view of this important cellular structure and its functions. However, the many functions now assigned to the nuclear envelope make it increasingly hard to determine which functions underlie these disorders. RECENT FINDINGS New nuclear envelope functions in genome organization, regulation and repair, signaling, and nuclear and cellular mechanics have been added to its classical barrier function. Arguments can be made for any of these functions mediating abnormality in nuclear envelope disorders and data exist supporting many. Moreover, transient and/or distal nuclear envelope connections to other cellular proteins and structures may increase the complexity of these disorders. SUMMARY Although the increased understanding of nuclear envelope functions has made it harder to distinguish specific causes of nuclear envelope disorders, this is because it has greatly expanded the spectrum of possible mechanisms underlying them. This change in perspective applies well beyond the known nuclear envelope disorders, potentially implicating the nuclear envelope in a much wider range of myopathies and neuropathies.
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Snyers L, Erhart R, Laffer S, Pusch O, Weipoltshammer K, Schöfer C. LEM4/ANKLE-2 deficiency impairs post-mitotic re-localization of BAF, LAP2α and LaminA to the nucleus, causes nuclear envelope instability in telophase and leads to hyperploidy in HeLa cells. Eur J Cell Biol 2017; 97:63-74. [PMID: 29254732 DOI: 10.1016/j.ejcb.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 01/01/2023] Open
Abstract
The human LEM-domain protein family is involved in fundamental aspects of nuclear biology. The LEM-domain interacts with the barrier-to-autointegration factor (BAF), which itself binds DNA. LEM-domain proteins LAP2, emerin and MAN1 are proteins of the inner nuclear membrane; they have important functions: maintaining the integrity of the nuclear lamina and regulating gene expression at the nuclear periphery. LEM4/ANKLE-2 has been proposed to participate in nuclear envelope reassembly after mitosis and to mediate dephosphorylation of BAF through binding to phosphatase PP2A. Here, we used CRISPR/Cas9 to create several cell lines deficient in LEM4/ANKLE-2. By using time-lapse video microscopy, we show that absence of this protein severely compromises the post mitotic re-association of the nuclear proteins BAF, LAP2α and LaminA to chromosomes. These defects give rise to a strong mechanical instability of the nuclear envelope in telophase and to a chromosomal instability leading to increased number of hyperploid cells. Reintroducing LEM4/ANKLE-2 in the cells by transfection could efficiently restore the telophase association of BAF and LAP2α to the chromosomes. This rescue phenotype was abolished for N- or C-terminally truncated mutants that had lost the capacity to bind PP2A. We demonstrate also that, in addition to binding to PP2A, LEM4/ANKLE-2 binds BAF through its LEM-domain, providing further evidence for a generic function of this domain as a principal interactor of BAF.
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Affiliation(s)
- Luc Snyers
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria.
| | - Renate Erhart
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Sylvia Laffer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Oliver Pusch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Klara Weipoltshammer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Christian Schöfer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
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27
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Samwer M, Schneider MWG, Hoefler R, Schmalhorst PS, Jude JG, Zuber J, Gerlich DW. DNA Cross-Bridging Shapes a Single Nucleus from a Set of Mitotic Chromosomes. Cell 2017; 170:956-972.e23. [PMID: 28841419 PMCID: PMC5638020 DOI: 10.1016/j.cell.2017.07.038] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/12/2017] [Accepted: 07/24/2017] [Indexed: 01/23/2023]
Abstract
Eukaryotic cells store their chromosomes in a single nucleus. This is important to maintain genomic integrity, as chromosomes packaged into separate nuclei (micronuclei) are prone to massive DNA damage. During mitosis, higher eukaryotes disassemble their nucleus and release individualized chromosomes for segregation. How numerous chromosomes subsequently reform a single nucleus has remained unclear. Using image-based screening of human cells, we identified barrier-to-autointegration factor (BAF) as a key factor guiding membranes to form a single nucleus. Unexpectedly, nuclear assembly does not require BAF's association with inner nuclear membrane proteins but instead relies on BAF's ability to bridge distant DNA sites. Live-cell imaging and in vitro reconstitution showed that BAF enriches around the mitotic chromosome ensemble to induce a densely cross-bridged chromatin layer that is mechanically stiff and limits membranes to the surface. Our study reveals that BAF-mediated changes in chromosome mechanics underlie nuclear assembly with broad implications for proper genome function.
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Affiliation(s)
- Matthias Samwer
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Maximilian W G Schneider
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Rudolf Hoefler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Philipp S Schmalhorst
- Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria
| | - Julian G Jude
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), 1030 Vienna, Austria.
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28
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Dixon CR, Platani M, Makarov AA, Schirmer EC. Microinjection of Antibodies Targeting the Lamin A/C Histone-Binding Site Blocks Mitotic Entry and Reveals Separate Chromatin Interactions with HP1, CenpB and PML. Cells 2017; 6:cells6020009. [PMID: 28346356 PMCID: PMC5492013 DOI: 10.3390/cells6020009] [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: 01/16/2017] [Revised: 02/24/2017] [Accepted: 03/14/2017] [Indexed: 02/07/2023] Open
Abstract
Lamins form a scaffold lining the nucleus that binds chromatin and contributes to spatial genome organization; however, due to the many other functions of lamins, studies knocking out or altering the lamin polymer cannot clearly distinguish between direct and indirect effects. To overcome this obstacle, we specifically targeted the mapped histone-binding site of A/C lamins by microinjecting antibodies specific to this region predicting that this would make the genome more mobile. No increase in chromatin mobility was observed; however, interestingly, injected cells failed to go through mitosis, while control antibody-injected cells did. This effect was not due to crosslinking of the lamin polymer, as Fab fragments also blocked mitosis. The lack of genome mobility suggested other lamin-chromatin interactions. To determine what these might be, mini-lamin A constructs were expressed with or without the histone-binding site that assembled into independent intranuclear structures. HP1, CenpB and PML proteins accumulated at these structures for both constructs, indicating that other sites supporting chromatin interactions exist on lamin A. Together, these results indicate that lamin A-chromatin interactions are highly redundant and more diverse than generally acknowledged and highlight the importance of trying to experimentally separate their individual functions.
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Affiliation(s)
- Charles R Dixon
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Melpomeni Platani
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Alexandr A Makarov
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
| | - Eric C Schirmer
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Kings Buildings, Swann 5.22, Max Born Crescent, Edinburgh EH9 3BF, UK.
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29
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de Las Heras JI, Zuleger N, Batrakou DG, Czapiewski R, Kerr ARW, Schirmer EC. Tissue-specific NETs alter genome organization and regulation even in a heterologous system. Nucleus 2017; 8:81-97. [PMID: 28045568 PMCID: PMC5287206 DOI: 10.1080/19491034.2016.1261230] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Different cell types exhibit distinct patterns of 3D genome organization that correlate with changes in gene expression in tissue and differentiation systems. Several tissue-specific nuclear envelope transmembrane proteins (NETs) have been found to influence the spatial positioning of genes and chromosomes that normally occurs during tissue differentiation. Here we study 3 such NETs: NET29, NET39, and NET47, which are expressed preferentially in fat, muscle and liver, respectively. We found that even when exogenously expressed in a heterologous system they can specify particular genome organization patterns and alter gene expression. Each NET affected largely different subsets of genes. Notably, the liver-specific NET47 upregulated many genes in HT1080 fibroblast cells that are normally upregulated in hepatogenesis, showing that tissue-specific NETs can favor expression patterns associated with the tissue where the NET is normally expressed. Similarly, global profiling of peripheral chromatin after exogenous expression of these NETs using lamin B1 DamID revealed that each NET affected the nuclear positioning of distinct sets of genomic regions with a significant tissue-specific component. Thus NET influences on genome organization can contribute to gene expression changes associated with differentiation even in the absence of other factors and overt cellular differentiation changes.
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Affiliation(s)
- Jose I de Las Heras
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Nikolaj Zuleger
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Dzmitry G Batrakou
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Rafal Czapiewski
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Alastair R W Kerr
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Eric C Schirmer
- a The Wellcome Trust Centre for Cell Biology , University of Edinburgh , Edinburgh , UK
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Zlopasa L, Brachner A, Foisner R. Nucleo-cytoplasmic shuttling of the endonuclease ankyrin repeats and LEM domain-containing protein 1 (Ankle1) is mediated by canonical nuclear export- and nuclear import signals. BMC Cell Biol 2016; 17:23. [PMID: 27245214 PMCID: PMC4888674 DOI: 10.1186/s12860-016-0102-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/19/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ankyrin repeats and LEM domain containing protein 1 (Ankle1) belongs to the LEM protein family, whose members share a chromatin-interacting LEM motif. Unlike most other LEM proteins, Ankle1 is not an integral protein of the inner nuclear membrane but shuttles between the nucleus and the cytoplasm. It contains a GIY-YIG-type nuclease domain, but its function is unknown. The mammalian genome encodes only one other GIY-YIG domain protein, termed Slx1. Slx1 has been described as a resolvase that processes Holliday junctions during homologous recombination-mediated DNA double strand break repair. Resolvase activity is regulated in a spatial and temporal manner during the cell cycle. We hypothesized that Ankle1 may have a similar function and its nucleo-cytoplasmic shuttling may contribute to the regulation of Ankle1 activity. Hence, we aimed at identifying the domains mediating Ankle1 shuttling and investigating whether cellular localization is affected during DNA damage response. RESULTS Sequence analysis predicts the presence of two canonical nuclear import and export signals in Ankle1. Immunofluorescence microscopy of cells expressing wild-type and various mutated Ankle1-fusion proteins revealed a C-terminally located classical monopartite nuclear localization signal and a centrally located CRM1-dependent nuclear export signal that mediate nucleo-cytoplasmic shuttling of Ankle1. These sequences are also functional in heterologous proteins. The predominant localization of Ankle1 in the cytoplasm, however, does not change upon induction of several DNA damage response pathways throughout the cell cycle. CONCLUSIONS We identified the domains mediating nuclear import and export of Ankle1. Ankle1's cellular localization was not affected following DNA damage.
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Affiliation(s)
- Livija Zlopasa
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Andreas Brachner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Roland Foisner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
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Czapiewski R, Robson MI, Schirmer EC. Anchoring a Leviathan: How the Nuclear Membrane Tethers the Genome. Front Genet 2016; 7:82. [PMID: 27200088 PMCID: PMC4859327 DOI: 10.3389/fgene.2016.00082] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/20/2016] [Indexed: 12/21/2022] Open
Abstract
It is well established that the nuclear envelope has many distinct direct connections to chromatin that contribute to genome organization. The functional consequences of genome organization on gene regulation are less clear. Even less understood is how interactions of lamins and nuclear envelope transmembrane proteins (NETs) with chromatin can produce anchoring tethers that can withstand the physical forces of and on the genome. Chromosomes are the largest molecules in the cell, making megadalton protein structures like the nuclear pore complexes and ribosomes seem small by comparison. Thus to withstand strong forces from chromosome dynamics an anchoring tether is likely to be much more complex than a single protein-protein or protein-DNA interaction. Here we will briefly review known NE-genome interactions that likely contribute to spatial genome organization, postulate in the context of experimental data how these anchoring tethers contribute to gene regulation, and posit several hypotheses for the physical nature of these tethers that need to be investigated experimentally. Significantly, disruption of these anchoring tethers and the subsequent consequences for gene regulation could explain how mutations in nuclear envelope proteins cause diseases ranging from muscular dystrophy to lipodystrophy to premature aging progeroid syndromes. The two favored hypotheses for nuclear envelope protein involvement in disease are (1) weakening nuclear and cellular mechanical stability, and (2) disrupting genome organization and gene regulation. Considerable experimental support has been obtained for both. The integration of both mechanical and gene expression defects in the disruption of anchoring tethers could provide a unifying hypothesis consistent with both.
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Affiliation(s)
| | | | - Eric C. Schirmer
- The Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, University of EdinburghEdinburgh, UK
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32
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Abstract
LAP2-emerin-MAN1 (LEM)-domain proteins are modular proteins characterized by the presence of a conserved motif of about 50 residues. Most LEM-domain proteins localize at the inner nuclear membrane, but some are also found in the endoplasmic reticulum or nuclear interior. Their architecture has been analyzed by predicting the limits of their globular domains, determining the 3D structure of these domains and in a few cases calculating the 3D structure of specific domains bound to biological targets. The LEM domain adopts an α-helical fold also found in SAP and HeH domains of prokaryotes and unicellular eukaryotes. The LEM domain binds to BAF (barrier-to-autointegration factor; BANF1), which interacts with DNA and tethers chromatin to the nuclear envelope. LAP2 isoforms also share an N-terminal LEM-like domain, which binds DNA. The structure and function of other globular domains that distinguish LEM-domain proteins from each other have been characterized, including the C-terminal dimerization domain of LAP2α and C-terminal WH and UHM domains of MAN1. LEM-domain proteins also have large intrinsically disordered regions that are involved in intra- and intermolecular interactions and are highly regulated by posttranslational modifications in vivo.
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33
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Chromatin at the nuclear periphery and the regulation of genome functions. Histochem Cell Biol 2015; 144:111-22. [PMID: 26170147 DOI: 10.1007/s00418-015-1346-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2015] [Indexed: 01/01/2023]
Abstract
Chromatin is not randomly organized in the nucleus, and its spatial organization participates in the regulation of genome functions. However, this spatial organization is also not entirely fixed and modifications of chromatin architecture are implicated in physiological processes such as differentiation or senescence. One of the most striking features of chromatin architecture is the concentration of heterochromatin at the nuclear periphery. A closer examination of the association of chromatin at the nuclear periphery reveals that heterochromatin accumulates at the nuclear lamina, whereas nuclear pores are usually devoid of heterochromatin. After summarizing the current techniques used to study the attachment of chromatin at the nuclear lamina or the nuclear pores, we review the mechanisms underlying these attachments, their plasticity and their consequences on the regulation of gene expression, DNA repair and replication.
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34
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Jamin A, Wiebe MS. Barrier to Autointegration Factor (BANF1): interwoven roles in nuclear structure, genome integrity, innate immunity, stress responses and progeria. Curr Opin Cell Biol 2015; 34:61-8. [PMID: 26072104 DOI: 10.1016/j.ceb.2015.05.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 05/20/2015] [Accepted: 05/27/2015] [Indexed: 11/24/2022]
Abstract
The Barrier to Autointegration Factor (BAF or BANF1) is an abundant, highly conserved DNA binding protein. BAF is involved in multiple pathways including mitosis, nuclear assembly, viral infection, chromatin and gene regulation and the DNA damage response. BAF is also essential for early development in metazoans and relevant to human physiology; BANF1 mutations cause a progeroid syndrome, placing BAF within the laminopathy disease spectrum. This review summarizes previous knowledge about BAF in the context of recent discoveries about its protein partners, posttranslational regulation, dynamic subcellular localizations and roles in disease, innate immunity, transposable elements and genome integrity.
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Affiliation(s)
- Augusta Jamin
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0900, USA; Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA
| | - Matthew S Wiebe
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0900, USA; Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA.
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35
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Barrier-to-Autointegration Factor 1 (BAF/BANF1) Promotes Association of the SETD1A Histone Methyltransferase with Herpes Simplex Virus Immediate-Early Gene Promoters. mBio 2015; 6:e00345-15. [PMID: 26015494 PMCID: PMC4447252 DOI: 10.1128/mbio.00345-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We have shown previously that A-type lamins and intranuclear localization of the herpes simplex virus (HSV) genome are critical for the formation of the VP16 activator complex on HSV immediate-early (IE) gene promoters in murine cells, which implies a critical role for lamin A and its associated proteins in HSV gene expression. Because barrier-to-autointegration factor 1 (BAF/BANF1) has been thought to bridge chromosomes to the nuclear lamina, we hypothesized that BAF might mediate viral genome targeting to the nuclear lamina. We found that overexpression of BAF enhances HSV-1 replication and knockdown of BAF decreases HSV gene expression, delays the kinetics of viral early replication compartment formation, and reduces viral yield compared to those in control small interfering RNA-transfected cells. However, BAF depletion did not affect genome complex targeting to the nuclear periphery. Instead, we found that the levels of a histone-modifying enzyme, SETD1A methyltransferase, and histone H3 lysine 4 trimethylation were reduced on IE and early (E) gene promoters in BAF-depleted cells during HSV lytic infection. Our results demonstrate a novel function of BAF as an epigenetic regulator of HSV lytic infection. We hypothesize that BAF facilitates IE and E gene expression by recruiting the SETD1A methyltransferase to viral IE and E gene promoters. The nuclear lamina is composed of lamin proteins and numerous lamina-associated proteins. Previously, the chromatin structure of DNA localized proximally to the lamina was thought to be characterized by heterochromatin marks associated with silenced genes. However, recent studies indicate that both heterochromatin- and euchromatin-rich areas coexist on the lamina. This paradigm suggests that lamins and lamina-associated proteins dynamically regulate epigenetic modifications of specific genes in different locations. Our goal is to understand how the lamina and its associated proteins regulate the epigenetics of genes through the study of HSV infection of human cells. We have shown previously that A-type lamins are critical for HSV genome targeting to the nuclear lamina and epigenetic regulation in viral replication. In this study, we found that another lamina-associated protein, BAF, regulates HSV gene expression through an epigenetic mechanism, which provides basic insights into the nuclear lamina and its associated proteins’ roles in epigenetic regulation.
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Nikalayevich E, Ohkura H. The NuRD nucleosome remodelling complex and NHK-1 kinase are required for chromosome condensation in oocytes. J Cell Sci 2015; 128:566-75. [PMID: 25501812 PMCID: PMC4311133 DOI: 10.1242/jcs.158477] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 12/05/2014] [Indexed: 12/31/2022] Open
Abstract
Chromosome condensation during cell division is one of the most dramatic events in the cell cycle. Condensin and topoisomerase II are the most studied factors in chromosome condensation. However, their inactivation leads to only mild defects and little is known about the roles of other factors. Here, we took advantage of Drosophilaoocytes to elucidate the roles of potential condensation factors by performing RNA interference (RNAi). Consistent with previous studies, depletion of condensin I subunits or topoisomerase II in oocytes only mildly affected chromosome condensation. In contrast, we found severe undercondensation of chromosomes after depletion of the Mi-2-containing NuRD nucleosome remodelling complex or the protein kinase NHK-1 (also known as Ballchen in Drosophila). The further phenotypic analysis suggests that Mi-2 and NHK-1 are involved in different pathways of chromosome condensation. We show that the main role of NHK-1 in chromosome condensation is to phosphorylate Barrier-to-autointegration factor (BAF) and suppress its activity in linking chromosomes to nuclear envelope proteins. We further show that NHK-1 is important for chromosome condensation during mitosis as well as in oocytes.
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Affiliation(s)
| | - Hiroyuki Ohkura
- Wellcome Trust Centre for Cell Biology, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JR, UK
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Shang YD, Zhang JL, Wang Y, Zhang HX, Zheng QC. Molecular simulation investigation on the interaction between barrier-to-autointegration factor dimer or its Gly25Glu mutant and LEM domain of emerin. Comput Biol Chem 2014; 53PB:184-190. [PMID: 25462326 DOI: 10.1016/j.compbiolchem.2014.09.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 02/06/2023]
Abstract
The interaction between barrier-to-autointegration factor dimer (BAF2) and LEM domain of emerin (EmLEM) was studied by molecular simulation methods. Nonspecific fragment of double-strand DNA molecule was docked with each chain of BAF2 by ZDOCK program. The model of DNA2:BAF2:EmLEM was thus constructed. The mutant Gly25Glu of BAF2 was manually constructed to explore the detailed effect of the mutation on the binding of BAF2 and EmLEM. It has been experimentally suggested that point mutation Gly25Glu can disturb the binding between BAF2 and EmLEM. Then, molecular dynamics (MD) simulations were performed on DNA2:BAF2(WT):EmLEM and DNA2:BAF2(MT):EmLEM complexes. 30ns trajectories revealed that the trajectory fluctuations of MT complex are more violent than that of the WT complex. Further, the binding free energy analysis showed that the electronegative residues Asp57, Glu61 and Asp65 from chain A, glu36 from chain B of BAF2 mainly contribute to interact with EmLEM. Besides, a stable π-π stack between trp62 and phe39 from BAF2(WT) chain B is destroyed by Glu25 in BAF2(MT). As a result, trp62 forms an interaction with glu25, and phe39 converts to strengthen affinity to EmLEM. On the other hand, Trp62 from chain A also forms a strong interaction with MT Glu25. Thus, with the docking of DNA, BAF2(MT) has higher affinity with EmLEM than BAF2(WT).
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Affiliation(s)
- Yu-Dong Shang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, PR China
| | - Ji-Long Zhang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, PR China
| | - Yan Wang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, PR China
| | - Hong-Xing Zhang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, PR China
| | - Qing-Chuan Zheng
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, PR China.
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Bar DZ, Davidovich M, Lamm AT, Zer H, Wilson KL, Gruenbaum Y. BAF-1 mobility is regulated by environmental stresses. Mol Biol Cell 2014; 25:1127-36. [PMID: 24501420 PMCID: PMC3967975 DOI: 10.1091/mbc.e13-08-0477] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Barrier to autointegration factor (BAF) is an essential component of the nuclear lamina that binds lamins, LEM-domain proteins, histones, and DNA. Under normal conditions, BAF protein is highly mobile when assayed by fluorescence recovery after photobleaching and fluorescence loss in photobleaching. We report that Caenorhabditis elegans BAF-1 mobility is regulated by caloric restriction, food deprivation, and heat shock. This was not a general response of chromatin-associated proteins, as food deprivation did not affect the mobility of heterochromatin protein HPL-1 or HPL-2. Heat shock also increased the level of BAF-1 Ser-4 phosphorylation. By using missense mutations that affect BAF-1 binding to different partners we find that, overall, the ability of BAF-1 mutants to be immobilized by heat shock in intestinal cells correlated with normal or increased affinity for emerin in vitro. These results show BAF-1 localization and mobility at the nuclear lamina are regulated by stress and unexpectedly reveal BAF-1 immobilization as a specific response to caloric restriction in C. elegans intestinal cells.
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Affiliation(s)
- Daniel Z Bar
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram Jerusalem 91904, Israel Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Abstract
There are many ways that the nuclear envelope can influence the cell cycle. In addition to roles of lamins in regulating the master cell cycle regulator pRb and nuclear envelope breakdown in mitosis, many other nuclear envelope proteins influence the cell cycle through regulatory or structural functions. Of particular note among these are the nuclear envelope transmembrane proteins (NETs) that appear to influence cell cycle regulation through multiple separate mechanisms. Some NETs and other nuclear envelope proteins accumulate on the mitotic spindle, suggesting functional or structural roles in the cell cycle. In interphase exogenous overexpression of some NETs promotes an increase in G1 populations, while others promote an increase in G2/M populations, sometimes associated with the induction of senescence. Intriguingly, most of the NETs linked to the cell cycle are highly restricted in their tissue expression; thus, their misregulation in cancer could contribute to the many tissue-specific types of cancer.
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Stancheva I, Schirmer EC. Nuclear Envelope: Connecting Structural Genome Organization to Regulation of Gene Expression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 773:209-44. [DOI: 10.1007/978-1-4899-8032-8_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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41
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Koch AJ, Holaska JM. Emerin in health and disease. Semin Cell Dev Biol 2013; 29:95-106. [PMID: 24365856 DOI: 10.1016/j.semcdb.2013.12.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/02/2013] [Accepted: 12/15/2013] [Indexed: 12/27/2022]
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is caused by mutations in the genes encoding emerin, lamins A and C and FHL1. Additional EDMD-like syndromes are caused by mutations in nesprins and LUMA. This review will specifically focus on emerin function and the current thinking for how loss or mutations in emerin cause EDMD. Emerin is a well-conserved, ubiquitously expressed protein of the inner nuclear membrane. Emerin has been shown to have diverse functions, including the regulation of gene expression, cell signaling, nuclear structure and chromatin architecture. This review will focus on the relationships between these functions and the EDMD disease phenotype. Additionally it will highlight open questions concerning emerin's roles in cell and nuclear biology and disease.
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Affiliation(s)
- Adam J Koch
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA.
| | - James M Holaska
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, IL 60637, USA; Committee on Developmental, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, IL 60637, USA.
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Zhuang X, Semenova E, Maric D, Craigie R. Dephosphorylation of barrier-to-autointegration factor by protein phosphatase 4 and its role in cell mitosis. J Biol Chem 2013; 289:1119-27. [PMID: 24265311 DOI: 10.1074/jbc.m113.492777] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Barrier-to-autointegration factor (BAF or BANF1) is highly conserved in multicellular eukaryotes and was first identified for its role in retroviral DNA integration. Homozygous BAF mutants are lethal and depletion of BAF results in defects in chromatin segregation during mitosis and subsequent nuclear envelope assembly. BAF exists both in phosphorylated and unphosphorylated forms with phosphorylation sites Thr-2, Thr-3, and Ser-4, near the N terminus. Vaccinia-related kinase 1 is the major kinase responsible for phosphorylation of BAF. We have identified the major phosphatase responsible for dephosphorylation of Ser-4 to be protein phosphatase 4 catalytic subunit. By examining the cellular distribution of phosphorylated BAF (pBAF) and total BAF (tBAF) through the cell cycle, we found that pBAF is associated with the core region of telophase chromosomes. Depletion of BAF or perturbing its phosphorylation state results not only in nuclear envelope defects, including mislocalization of LEM domain proteins and extensive invaginations into the nuclear interior, but also impaired cell cycle progression. This phenotype is strikingly similar to that seen in cells from patients with progeroid syndrome resulting from a point mutation in BAF.
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Reil M, Dabauvalle MC. Essential roles of LEM-domain protein MAN1 during organogenesis in Xenopus laevis and overlapping functions of emerin. Eur J Cell Biol 2013; 92:280-94. [PMID: 24252515 DOI: 10.1016/j.ejcb.2013.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 10/23/2013] [Accepted: 10/25/2013] [Indexed: 11/26/2022] Open
Abstract
Mutations in nuclear envelope proteins are linked to an increasing number of human diseases, called envelopathies. Mutations in the inner nuclear membrane protein emerin lead to X-linked Emery-Dreifuss muscular dystrophy, characterized by muscle weakness or wasting. Conversely, mutations in nuclear envelope protein MAN1 are linked to bone and skin disorders. Both proteins share a highly conserved domain, called LEM-domain. LEM proteins are known to interact with Barrier-to-autointegration factor and several transcription factors. Most envelopathies are tissue-specific, but knowledge on the physiological roles of related LEM proteins is still unclear. For this reason, we investigated the roles of MAN1 and emerin during Xenopus laevis organogenesis. Morpholino-mediated knockdown of MAN1 revealed that MAN1 is essential for the formation of eye, skeletal and cardiac muscle tissues. The MAN1 knockdown could be compensated by ectopic expression of emerin, leading to a proper organ development. Further investigations revealed that MAN1 is involved in regulation of genes essential for organ development and tissue homeostasis. Thereby our work supports that LEM proteins might be involved in signalling essential for organ development during early embryogenesis and suggests that loss of MAN1 may cause muscle and retina specific diseases.
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Affiliation(s)
- Michael Reil
- Division of Electron Microscopy, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany.
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44
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Ibrahim N, Wicklund A, Jamin A, Wiebe MS. Barrier to autointegration factor (BAF) inhibits vaccinia virus intermediate transcription in the absence of the viral B1 kinase. Virology 2013; 444:363-73. [PMID: 23891157 DOI: 10.1016/j.virol.2013.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 05/01/2013] [Accepted: 07/02/2013] [Indexed: 11/16/2022]
Abstract
Barrier to autointegration factor (BAF/BANF1) is a cellular DNA-binding protein found in the nucleus and cytoplasm. Cytoplasmic BAF binds to foreign DNA and can act as a defense against vaccinia DNA replication. To evade BAF, vaccinia expresses the B1 kinase, which phosphorylates BAF and blocks its ability to bind DNA. Interestingly, B1 is also needed for viral intermediate gene expression via an unknown mechanism. Therefore, we evaluated the impact of B1-BAF signaling on vaccinia transcription. Strikingly, the decrease in vaccinia transcription caused by loss of B1 can be rescued by depletion of BAF. The repressive action of BAF is greatest on a viral promoter, and is more modest when non-vaccinia promoters are employed, which suggests BAF acts in a gene specific manner. These studies expand our understanding of the role of the B1 kinase during infection and provide the first evidence that BAF is a defense against viral gene expression.
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Affiliation(s)
- Nouhou Ibrahim
- Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA
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Zuleger N, Kelly DA, Schirmer EC. Considering discrete protein pools when measuring the dynamics of nuclear membrane proteins. Methods Mol Biol 2013; 1042:275-298. [PMID: 23980015 DOI: 10.1007/978-1-62703-526-2_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Measuring dynamics of nuclear proteins is complicated by the fact that many DNA- and chromatin-binding proteins have separate nucleoplasmic and nuclear membrane pools with distinct mobilities. Moreover, when measuring recoveries in FRAP experiments, it is important to be aware that the continuous transport of new protein through the nuclear pore complexes means that fluorescence recovery comes from both dynamic exchange of protein already within the nucleus and newly imported protein. Here we describe fluorescence recovery after photobleaching and photoactivation techniques designed to track nuclear membrane proteins and some methods we have developed that may help to distinguish these various pools. A combination of these approaches with standard FRAP approaches is necessary to understand the true dynamics of nuclear proteins.
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Affiliation(s)
- Nikolaj Zuleger
- The Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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46
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Korfali N, Wilkie GS, Swanson SK, Srsen V, de Las Heras J, Batrakou DG, Malik P, Zuleger N, Kerr ARW, Florens L, Schirmer EC. The nuclear envelope proteome differs notably between tissues. Nucleus 2012; 3:552-64. [PMID: 22990521 PMCID: PMC3515538 DOI: 10.4161/nucl.22257] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
One hypothesis to explain how mutations in the same nuclear envelope proteins yield pathologies focused in distinct tissues is that as yet unidentified tissue-specific partners mediate the disease pathologies. The nuclear envelope proteome was recently determined from leukocytes and muscle. Here the same methodology is applied to liver and a direct comparison of the liver, muscle and leukocyte data sets is presented. At least 74 novel transmembrane proteins identified in these studies have been directly confirmed at the nuclear envelope. Within this set, RT-PCR, western blot and staining of tissue cryosections confirms that the protein complement of the nuclear envelope is clearly distinct from one tissue to another. Bioinformatics reveals similar divergence between tissues across the larger data sets. For proteins acting in complexes according to interactome data, the whole complex often exhibited the same tissue-specificity. Other tissue-specific nuclear envelope proteins identified were known proteins with functions in signaling and gene regulation. The high tissue specificity in the nuclear envelope likely underlies the complex disease pathologies and argues that all organelle proteomes warrant re-examination in multiple tissues.
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Affiliation(s)
- Nadia Korfali
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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47
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Brachner A, Braun J, Ghodgaonkar M, Castor D, Zlopaša L, Ehrlich V, Jiricny J, Gotzmann J, Knasmüller S, Foisner R. The endonuclease Ankle1 requires its LEM and GIY-YIG motifs for DNA cleavage in vivo. J Cell Sci 2012; 125:1048-57. [PMID: 22399800 PMCID: PMC4335191 DOI: 10.1242/jcs.098392] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The LEM domain (for lamina-associated polypeptide, emerin, MAN1 domain) defines a group of nuclear proteins that bind chromatin through interaction of the LEM motif with the conserved DNA crosslinking protein, barrier-to-autointegration factor (BAF). Here, we describe a LEM protein annotated in databases as 'Ankyrin repeat and LEM domain-containing protein 1' (Ankle1). We show that Ankle1 is conserved in metazoans and contains a unique C-terminal GIY-YIG motif that confers endonuclease activity in vitro and in vivo. In mammals, Ankle1 is predominantly expressed in hematopoietic tissues. Although most characterized LEM proteins are components of the inner nuclear membrane, ectopic Ankle1 shuttles between cytoplasm and nucleus. Ankle1 enriched in the nucleoplasm induces DNA cleavage and DNA damage response. This activity requires both the catalytic C-terminal GIY-YIG domain and the LEM motif, which binds chromatin via BAF. Hence, Ankle1 is an unusual LEM protein with a GIY-YIG-type endonuclease activity in higher eukaryotes.
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Affiliation(s)
- Andreas Brachner
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna, Austria
| | - Juliane Braun
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna, Austria
| | - Medini Ghodgaonkar
- Institute of Molecular Cancer Research, University of Zurich, Switzerland
| | - Dennis Castor
- Institute of Molecular Cancer Research, University of Zurich, Switzerland
| | - Livija Zlopaša
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna, Austria
| | - Veronika Ehrlich
- Institute of Cancer Research, Inner Medicine I, Medical University of Vienna, Austria
| | - Josef Jiricny
- Institute of Molecular Cancer Research, University of Zurich, Switzerland
| | - Josef Gotzmann
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna, Austria
| | - Siegfried Knasmüller
- Institute of Cancer Research, Inner Medicine I, Medical University of Vienna, Austria
| | - Roland Foisner
- Max F. Perutz Laboratories, Medical University of Vienna, Dr. Bohr-Gasse 9, Vienna, Austria
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de Las Heras JI, Batrakou DG, Schirmer EC. Cancer biology and the nuclear envelope: a convoluted relationship. Semin Cancer Biol 2012; 23:125-37. [PMID: 22311402 DOI: 10.1016/j.semcancer.2012.01.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 01/16/2012] [Accepted: 01/19/2012] [Indexed: 12/23/2022]
Abstract
Although its properties have long been used for both typing and prognosis of various tumors, the nuclear envelope (NE) itself and its potential roles in tumorigenesis are only beginning to be understood. Historically viewed as merely a protective barrier, the nuclear envelope is now linked to a wide range of functions. Nuclear membrane proteins connect the nucleus to the cytoskeleton on one side and to chromatin on the other. Several newly identified nuclear envelope functions associated with these connections intersect with cancer pathways. For example, the nuclear envelope could affect genome stability by tethering chromatin. Some nuclear envelope proteins affect cell cycle regulation by directly binding to the master regulator pRb, others by interacting with TGF-ß and Smad signaling cascades, and others by affecting the mitotic spindle. Finally, the NE directly affects cytoskeletal organization and can also influence cell migration in metastasis. In this review we discuss the link between the nuclear envelope and cellular defects that are common in cancer cells, and we show that NE proteins are often aberrantly expressed in tumors. The NE represents a potential reservoir of diagnostic and prognostic markers in cancer.
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Affiliation(s)
- Jose I de Las Heras
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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Structural determinants for nuclear envelope localization and function of pseudorabies virus pUL34. J Virol 2011; 86:2079-88. [PMID: 22156520 DOI: 10.1128/jvi.05484-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Herpesvirus proteins pUL34 and pUL31 form a complex at the inner nuclear membrane (INM) which is necessary for efficient nuclear egress. Pseudorabies virus (PrV) pUL34 is a type II membrane protein of 262 amino acids (aa). The transmembrane region (TM) is predicted to be located between aa 245 and 261, leaving only one amino acid in the C terminus that probably extends into the perinuclear space. It is targeted to the nuclear envelope in the absence of other viral proteins, pointing to intrinsic localization motifs, and shows structural similarity to cellular INM proteins like lamina-associated polypeptide (Lap) 2ß and Emerin. To investigate which domains of pUL34 are relevant for localization and function, we constructed chimeric proteins by replacing parts of pUL34 with regions of cellular INM proteins. First the 18 C-terminal amino acids encompassing the TM were exchanged with TM regions and C-terminal domains of Lap2ß and Emerin or with the first TM region of the polytopic lamin B receptor (LBR), including the nine following amino acids. All resulting chimeric proteins complemented the replication defect of PrV-ΔUL34, demonstrating that the substitution of the TM and the extension of the C-terminal domain does not interfere with the function of pUL34. Complementation was reduced but not abolished when the C-terminal 50 aa were replaced by corresponding Lap2ß sequences (pUL34-LapCT50). However, replacing the C-terminal 100 aa (pUL34-LapCT100) resulted in a nonfunctional protein despite continuing pUL31 binding, pointing to an important functional role of this region. The replacement of the N-terminal 100 aa (pUL34-LapNT100) had no effect on nuclear envelope localization but abrogated pUL31 binding and function.
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50
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Abstract
In metazoan cells, the heterochromatin is generally localized at the nuclear periphery, whereas active genes are preferentially found in the nuclear interior. In the present paper, we review current evidence showing that components of the nuclear lamina interact directly with heterochromatin, which implicates the nuclear lamina in a mechanism of specific gene retention at the nuclear periphery and release to the nuclear interior upon gene activation. We also discuss recent data showing that mutations in lamin proteins affect gene positioning and expression, providing a potential mechanism for how these mutations lead to tissue-specific diseases.
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