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Francia ME, Bhavsar S, Ting LM, Croken MM, Kim K, Dubremetz JF, Striepen B. A Homolog of Structural Maintenance of Chromosome 1 Is a Persistent Centromeric Protein Which Associates With Nuclear Pore Components in Toxoplasma gondii. Front Cell Infect Microbiol 2020; 10:295. [PMID: 32714878 PMCID: PMC7343853 DOI: 10.3389/fcimb.2020.00295] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 05/19/2020] [Indexed: 01/02/2023] Open
Abstract
Apicomplexa are obligate intracellular parasites which cause various animal and human diseases including malaria, toxoplasmosis, and cryptosporidiosis. They proliferate by a unique mechanism that combines physically separated semi-closed mitosis of the nucleus and assembly of daughter cells by internal budding. Mitosis occurs in the presence of a nuclear envelope and with little appreciable chromatin condensation. A long standing question in the field has been how parasites keep track of their uncondensed chromatin chromosomes throughout their development, and hence secure proper chromosome segregation during division. Past work demonstrated that the centromeres, the region of kinetochore assembly at chromosomes, of Toxoplasma gondii remain clustered at a defined region of the nuclear periphery proximal to the main microtubule organizing center of the cell, the centrosome. We have proposed that this mechanism is likely involved in the process. Here we set out to identify underlying molecular players involved in centromere clustering. Through pharmacological treatment and structural analysis we show that centromere clustering is not mediated by persistent microtubules of the mitotic spindle. We identify the chromatin binding factor a homolog of structural maintenance of chromosomes 1 (SMC1). Additionally, we show that both TgSMC1, and a centromeric histone, interact with TgExportin1, a predicted soluble component of the nuclear pore complex. Our results suggest that the nuclear envelope, and in particular the nuclear pore complex may play a role in positioning centromeres in T. gondii.
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Affiliation(s)
- Maria E Francia
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Sheila Bhavsar
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
| | - Li-Min Ting
- Morsani College of Medicine, University of South Florida Health, Tampa, FL, United States
| | - Matthew M Croken
- Pathology, Molecular and Cell Based Medicine, Mount Sinai Medical Center, New York, NY, United States
| | - Kami Kim
- Morsani College of Medicine, University of South Florida Health, Tampa, FL, United States
| | | | - Boris Striepen
- Department of Cellular Biology, University of Georgia, Athens, GA, United States.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
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Bitetto G, Ronchi D, Bonato S, Pittaro A, Compagnoni GM, Bordoni A, Salani S, Frattini E, Lopez G, Cribiù FM, Corti S, Comi GP, Bresolin N, Di Fonzo A. Loss of the nucleoporin Aladin in central nervous system and fibroblasts of Allgrove Syndrome. Hum Mol Genet 2020; 28:3921-3927. [PMID: 31600784 DOI: 10.1093/hmg/ddz236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/04/2019] [Accepted: 09/07/2019] [Indexed: 11/12/2022] Open
Abstract
Allgrove syndrome (AS) is a rare disease with broad neurological involvement. Neurodegeneration can affect spinal motor neurons, Purkinje cells, striatal neurons and the autonomic system. The mechanisms that lead to neuronal loss are still unclear. Recessive mutations in the AAAS gene affect the encoded protein Aladin, which would normally localize to the cytoplasmic face of the nuclear membrane as part of the nuclear pore complex (NPC). While the NPC is known to be a key factor for nucleocytoplasmic transport, the precise role of Aladin has not been elucidated yet. Here, we explored the consequences of the homozygous AAAS mutation c.464G>A (p.R155H) in central nervous system tissues and fibroblasts of a novel AS patient presenting motor neuron disease, cerebellar ataxia and autonomic dysfunction. Neuropathological analyses showed severe loss of motor neurons and Purkinje cells, with significant reduction in the perinuclear expression of Aladin. A reduced amount of protein was detected in the nuclear membrane fraction of the patient's brain. RNA analysis revealed a significant reduction of the transcript AAAS-1, while the AAAS-2 transcript was upregulated in fibroblasts. To our knowledge, this is the first study to demonstrate the effects of AAAS mutations in the human central nervous system.
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Affiliation(s)
- Giacomo Bitetto
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Dario Ronchi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Sara Bonato
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Alessandra Pittaro
- Division of Pathology, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- University of Milan, Milan, Italy
| | - Giacomo Monzio Compagnoni
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Andreina Bordoni
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Sabrina Salani
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Emanuele Frattini
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Gianluca Lopez
- Division of Pathology, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- University of Milan, Milan, Italy
| | - Fulvia Milena Cribiù
- Division of Pathology, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- University of Milan, Milan, Italy
| | - Stefania Corti
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Giacomo P Comi
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Nereo Bresolin
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Alessio Di Fonzo
- Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
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Nuclear Translocation Sequence and Region in Autographa californica Multiple Nucleopolyhedrovirus ME53 That Are Important for Optimal Baculovirus Production. J Virol 2016; 90:3953-3965. [PMID: 26842471 DOI: 10.1128/jvi.03115-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Autographa californicamultiple nucleopolyhedrovirus (AcMNPV) is in the familyBaculoviridae, genusAlphabaculovirus AcMNPVme53is a highly conserved immediate early gene in all lepidopteran baculoviruses that have been sequenced and is transcribed up to late times postinfection. Althoughme53is not essential for viral DNA synthesis, infectious budded virus (BV) production is greatly attenuated when it is deleted. ME53 associates with the nucleocapsid on both budded virus and occlusion-derived virus, but not with the virus envelope. ME53 colocalizes in plasma membrane foci with the envelope glycoprotein GP64 in a GP64-dependent manner. ME53 localizes in the cytoplasm early postinfection, and despite the lack of a reported nuclear localization signal (NLS), ME53 translocates to the nucleus at late times postinfection. To map determinants of ME53 that facilitate its nuclear translocation, recombinant AcMNPV bacmids containing a series of ME53 truncations, internal deletions, and peptides fused with hemagglutinin (HA) or green fluorescent protein (GFP) tags were constructed. Intracellular-localization studies identified residues within amino acids 109 to 137 at the N terminus of ME53 that acted as the nuclear translocation sequence (NTS), facilitating its nuclear transport at late times postinfection. The first 100 N-terminal amino acids and the last 50 C-terminal amino acids of ME53 are dispensable for high levels of budded virus production. The region within amino acids 101 to 398, which also contains the NTS, is critical for optimal levels of budded virus production. IMPORTANCE Baculovirusme53is a conserved immediate early gene found in all sequenced lepidopteran alpha- and betabaculoviruses. We first identified residues within amino acids 109 to 137 at the N terminus that act as the ME53 nuclear translocation sequence (NTS) to facilitate its nuclear translocation and defined an internal region within amino acids 101 to 398, which includes the NTS, as being necessary for optimal budded virus production. Altogether, these results indicate a previously unidentified nuclear role that ME53 plays in virus replication.
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4Pi microscopy of the nuclear pore complex. Methods Mol Biol 2014; 1251:193-211. [PMID: 25391801 DOI: 10.1007/978-1-4939-2080-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
4Pi microscopy is a far-field fluorescence microscopy technique, in which the wave fronts of two opposing illuminating beams are adjusted to constructively interfere in a common focus. This yields a diffraction pattern in the direction of the optical axis, which essentially consists of a main focal spot accompanied by two smaller side lobes. At optimal conditions, the main peak of this so-called point spread function has a full width at half maximum: fixed phrase of 100 nm in the direction of the optical axis, and thus is 6-7-fold smaller than that of a confocal microscope. In this chapter, we describe the basic features of 4Pi microscopy and its application to cell biology using the example of the nuclear pore complex, a large protein assembly spanning the nuclear envelope.
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Kelich JM, Yang W. High-resolution imaging reveals new features of nuclear export of mRNA through the nuclear pore complexes. Int J Mol Sci 2014; 15:14492-504. [PMID: 25141104 PMCID: PMC4159864 DOI: 10.3390/ijms150814492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/08/2014] [Accepted: 08/15/2014] [Indexed: 12/20/2022] Open
Abstract
The nuclear envelope (NE) of eukaryotic cells provides a physical barrier for messenger RNA (mRNA) and the associated proteins (mRNPs) traveling from sites of transcription in the nucleus to locations of translation processing in the cytoplasm. Nuclear pore complexes (NPCs) embedded in the NE serve as a dominant gateway for nuclear export of mRNA. However, the fundamental characterization of export dynamics of mRNPs through the NPC has been hindered by several technical limits. First, the size of NPC that is barely below the diffraction limit of conventional light microscopy requires a super-resolution microscopy imaging approach. Next, the fast transit of mRNPs through the NPC further demands a high temporal resolution by the imaging approach. Finally, the inherent three-dimensional (3D) movements of mRNPs through the NPC demand the method to provide a 3D mapping of both transport kinetics and transport pathways of mRNPs. This review will highlight the recently developed super-resolution imaging techniques advanced from 1D to 3D for nuclear export of mRNPs and summarize the new features in the dynamic nuclear export process of mRNPs revealed from these technical advances.
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Affiliation(s)
- Joseph M Kelich
- Department of Biology, Temple University, Philadelphia, PA 19122, USA.
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA 19122, USA.
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Osmanović D, Ford IJ, Hoogenboom BW. Model inspired by nuclear pore complex suggests possible roles for nuclear transport receptors in determining its structure. Biophys J 2014; 105:2781-9. [PMID: 24359750 DOI: 10.1016/j.bpj.2013.11.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 10/25/2013] [Accepted: 11/04/2013] [Indexed: 12/20/2022] Open
Abstract
Nuclear transport receptors (NTRs) mediate nucleocytoplasmic transport via their affinity for unstructured proteins (polymers) in the nuclear pore complex (NPC). Here, we have modeled the effect of NTRs on polymeric structure in the nanopore confinement of the NPC central conduit. The model explicitly takes into account inter- and intramolecular interactions, as well as the finite size of the NTRs (∼20% of the NPC channel diameter). It reproduces various proposed scenarios for the channel structure, ranging from a central polymer condensate (selective phase) to brushlike polymer arrangements localized at the channel wall (virtual gate, reduction of dimensionality), with the transport receptors lining the polymer surface. In addition, it predicts a new structure in which NTRs become an integral part of the transport barrier by forming a cross-linked network with the unstructured proteins stretching across the pore. The model provides specific and distinctive predictions for the equilibrium spatial distributions of NTRs for these different scenarios that can be experimentally verified by, e.g., superresolution fluorescence microscopy. Moreover, it suggests mechanisms by which globular macromolecules (colloidal particles) can cause polymer-coated nanopores to switch between open and closed configurations, a possible explanation of the biological function of the NPC, and suggests potential technological applications for filtration and single-molecule sensing.
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Affiliation(s)
- Dino Osmanović
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom.
| | - Ian J Ford
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Bart W Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London, United Kingdom
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Twyffels L, Gueydan C, Kruys V. Transportin-1 and Transportin-2: protein nuclear import and beyond. FEBS Lett 2014; 588:1857-68. [PMID: 24780099 DOI: 10.1016/j.febslet.2014.04.023] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 04/12/2014] [Accepted: 04/16/2014] [Indexed: 12/22/2022]
Abstract
Nearly 20 years after its identification as a new β-karyopherin mediating the nuclear import of the RNA-binding protein hnRNP A1, Transportin-1 is still commonly overlooked in comparison with its best known cousin, Importin-β. Transportin-1 is nonetheless a considerable player in nucleo-cytoplasmic transport. Over the past few years, significant progress has been made in the characterization of the nuclear localization signals (NLSs) that Transportin-1 recognizes, thereby providing the molecular basis of its diversified repertoire of cargoes. The recent discovery that mutations in the Transportin-dependent NLS of FUS cause mislocalization of this protein and result in amyotrophic lateral sclerosis illustrates the importance of Transportin-dependent import for human health. Besides, new functions of Transportin-1 are emerging in processes other than nuclear import. Here, we summarize what is known about Transportin-1 and the related β-karyopherin Transportin-2.
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Affiliation(s)
- Laure Twyffels
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium.
| | - Cyril Gueydan
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium
| | - Véronique Kruys
- Laboratoire de Biologie moléculaire du gène (CP300), Faculté des Sciences, Université Libre de Bruxelles (ULB), Belgium; Center for Microscopy and Molecular Imaging (CMMI), 6041 Gosselies, Belgium
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Poring over pores: nuclear pore complex insertion into the nuclear envelope. Trends Biochem Sci 2013; 38:292-301. [DOI: 10.1016/j.tibs.2013.04.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 03/29/2013] [Accepted: 04/02/2013] [Indexed: 11/18/2022]
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Meinema AC, Poolman B, Veenhoff LM. Quantitative Analysis of Membrane Protein Transport Across the Nuclear Pore Complex. Traffic 2013; 14:487-501. [DOI: 10.1111/tra.12048] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Anne C. Meinema
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre, Zernike Institute for Advanced Materials; University of Groningen; Nijenborgh 4; 9747 AG; Groningen; the Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre, Zernike Institute for Advanced Materials; University of Groningen; Nijenborgh 4; 9747 AG; Groningen; the Netherlands
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Löschberger A, van de Linde S, Dabauvalle MC, Rieger B, Heilemann M, Krohne G, Sauer M. Super-resolution imaging visualizes the eightfold symmetry of gp210 proteins around the nuclear pore complex and resolves the central channel with nanometer resolution. J Cell Sci 2012; 125:570-5. [PMID: 22389396 DOI: 10.1242/jcs.098822] [Citation(s) in RCA: 214] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
One of the most complex molecular machines of cells is the nuclear pore complex (NPC), which controls all trafficking of molecules in and out of the nucleus. Because of their importance for cellular processes such as gene expression and cytoskeleton organization, the structure of NPCs has been studied extensively during the last few decades, mainly by electron microscopy. We have used super-resolution imaging by direct stochastic optical reconstruction microscopy (dSTORM) to investigate the structure of NPCs in isolated Xenopus laevis oocyte nuclear envelopes, with a lateral resolution of ~15 nm. By generating accumulated super-resolved images of hundreds of NPCs we determined the diameter of the central NPC channel to be 41 ± 7 nm and demonstrate that the integral membrane protein gp210 is distributed in an eightfold radial symmetry. Two-color dSTORM experiments emphasize the highly symmetric NPCs as ideal model structures to control the quality of corrections to chromatic aberration and to test the capability and reliability of super-resolution imaging methods.
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Affiliation(s)
- Anna Löschberger
- Department of Biotechnology and Biophysics, Biozentrum, Julius Maximilians University Würzburg, Am Hubland, 97074 Würzburg, Germany
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Boruc J, Zhou X, Meier I. Dynamics of the plant nuclear envelope and nuclear pore. PLANT PHYSIOLOGY 2012; 158:78-86. [PMID: 21949214 PMCID: PMC3252082 DOI: 10.1104/pp.111.185256] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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