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Carl SH, Fassnacht C, Knuckles P, Varypataki EM, Chang YT, Tsai YC, Ignatova D, Widmer C, Vonow-Eisenring M, Ugrinic M, Bittermann AG, Pascolo S, Theocharides A, Hoetzenecker W, Bourquin JP, Eyerich K, Claassen M, Guenova E. Mass cytometry and machine learning delineate tumor-defining cells in Sézary syndrome to allow discrimination from benign erythroderma. Eur J Cancer 2021. [DOI: 10.1016/s0959-8049(21)00636-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Panneels V, Diaz A, Imsand C, Guizar-Sicairos M, Müller E, Bittermann AG, Ishikawa T, Menzel A, Kaech A, Holler M, Grimm C, Schertler G. Imaging of retina cellular and subcellular structures using ptychographic hard X-ray tomography. J Cell Sci 2021; 134:272479. [PMID: 34494099 DOI: 10.1242/jcs.258561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 09/01/2021] [Indexed: 11/20/2022] Open
Abstract
Ptychographic hard X-ray computed tomography (PXCT) is a recent method allowing imaging with quantitative electron-density contrast. Here, we imaged, at cryogenic temperature and without sectioning, cellular and subcellular structures of a chemically fixed and stained wild-type mouse retina, including axons and synapses, with complete isotropic 3D information over tens of microns. Comparison with tomograms of degenerative retina from a mouse model of retinitis pigmentosa illustrates the potential of this method for analyzing disease processes like neurodegeneration at sub-200 nm resolution. As a non-destructive imaging method, PXCT is very suitable for correlative imaging. Within the outer plexiform layer containing the photoreceptor synapses, we identified somatic synapses. We used a small region inside the X-ray-imaged sample for further high-resolution focused ion beam/scanning electron microscope tomography. The subcellular structures of synapses obtained with the X-ray technique matched the electron microscopy data, demonstrating that PXCT is a powerful scanning method for tissue volumes of more than 60 cells and sensitive enough for identification of regions as small as 200 nm, which remain available for further structural and biochemical investigations.
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Affiliation(s)
- Valerie Panneels
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Ana Diaz
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Cornelia Imsand
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, 8952 Schlieren, Switzerland
| | - Manuel Guizar-Sicairos
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Elisabeth Müller
- Division of Biology and Chemistry, Laboratory for Nanoscale Biology, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Anne Greet Bittermann
- ScopeM, Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Takashi Ishikawa
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland.,Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Andreas Menzel
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, 8006 Zurich, Switzerland
| | - Mirko Holler
- Division of Photon Science, Laboratory for Macromolecules and Bioimaging, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Christian Grimm
- Laboratory for Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, University of Zurich, 8952 Schlieren, Switzerland
| | - Gebhard Schertler
- Division of Biology and Chemistry, Laboratory for Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland.,Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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Diaz A, Malkova B, Holler M, Guizar-Sicairos M, Lima E, Panneels V, Pigino G, Bittermann AG, Wettstein L, Tomizaki T, Bunk O, Schertler G, Ishikawa T, Wepf R, Menzel A. Addendum to “Three-dimensional mass density mapping of cellular ultrastructure by ptychographic X-ray nanotomography” [J. Struct. Biol. 192 (2015) 461–469]. J Struct Biol 2016. [DOI: 10.1016/j.jsb.2015.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Diaz A, Malkova B, Holler M, Guizar-Sicairos M, Lima E, Panneels V, Pigino G, Bittermann AG, Wettstein L, Tomizaki T, Bunk O, Schertler G, Ishikawa T, Wepf R, Menzel A. Three-dimensional mass density mapping of cellular ultrastructure by ptychographic X-ray nanotomography. J Struct Biol 2015; 192:461-469. [DOI: 10.1016/j.jsb.2015.10.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 11/16/2022]
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Abstract
Three-dimensional information is much easier to understand than a set of two-dimensional images. Therefore a layman is thrilled by the pseudo-3D image taken in a scanning electron microscope (SEM) while, when seeing a transmission electron micrograph, his imagination is challenged. First approaches to gain insight in the third dimension were to make serial microtome sections of a region of interest (ROI) and then building a model of the object. Serial microtome sectioning is a tedious and skill-demanding work and therefore seldom done. In the last two decades with the increase of computer power, sophisticated display options, and the development of new instruments, an SEM with a built-in microtome as well as a focused ion beam scanning electron microscope (FIB-SEM), serial sectioning, and 3D analysis has become far easier and faster.Due to the relief like topology of the microtome trimmed block face of resin-embedded tissue, the ROI can be searched in the secondary electron mode, and at the selected spot, the ROI is prepared with the ion beam for 3D analysis. For FIB-SEM tomography, a thin slice is removed with the ion beam and the newly exposed face is imaged with the electron beam, usually by recording the backscattered electrons. The process, also called "slice and view," is repeated until the desired volume is imaged.As FIB-SEM allows 3D imaging of biological fine structure at high resolution of only small volumes, it is crucial to perform slice and view at carefully selected spots. Finding the region of interest is therefore a prerequisite for meaningful imaging. Thin layer plastification of biofilms offers direct access to the original sample surface and allows the selection of an ROI for site-specific FIB-SEM tomography just by its pronounced topographic features.
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Affiliation(s)
- Caroline Kizilyaprak
- Electron Microscopy Facility, Biophore, University of Lausanne, Lausanne, Switzerland
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Schaer CA, Deuel JW, Bittermann AG, Rubio IG, Schoedon G, Spahn DR, Wepf RA, Vallelian F, Schaer DJ. Mechanisms of haptoglobin protection against hemoglobin peroxidation triggered endothelial damage. Cell Death Differ 2013; 20:1569-79. [PMID: 23995229 PMCID: PMC3792434 DOI: 10.1038/cdd.2013.113] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/20/2013] [Accepted: 07/15/2013] [Indexed: 01/30/2023] Open
Abstract
Extracellular hemoglobin (Hb) has been recognized as a disease trigger in hemolytic conditions such as sickle cell disease, malaria, and blood transfusion. In vivo, many of the adverse effects of free Hb can be attenuated by the Hb scavenger acute-phase protein haptoglobin (Hp). The primary physiologic disturbances that can be caused by free Hb are found within the cardiovascular system and Hb-triggered oxidative toxicity toward the endothelium has been promoted as a potential mechanism. The molecular mechanisms of this toxicity as well as of the protective activities of Hp are not yet clear. Within this study, we systematically investigated the structural, biochemical, and cell biologic nature of Hb toxicity in an endothelial cell system under peroxidative stress. We identified two principal mechanisms of oxidative Hb toxicity that are mediated by globin degradation products and by modified lipoprotein species, respectively. The two damage pathways trigger diverse and discriminative inflammatory and cytotoxic responses. Hp provides structural stabilization of Hb and shields Hb's oxidative reactions with lipoproteins, providing dramatic protection against both pathways of toxicity. By these mechanisms, Hp shifts Hb's destructive pseudo-peroxidative reaction to a potential anti-oxidative function during peroxidative stress.
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Affiliation(s)
- C A Schaer
- Institute of Anesthesiology, University Hospital, Zurich, Switzerland
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Semenov OV, Malek A, Bittermann AG, Vörös J, Zisch AH. Engineered Polyelectrolyte Multilayer Substrates for Adhesion, Proliferation, and Differentiation of Human Mesenchymal Stem Cells. Tissue Eng Part A 2009; 15:2977-90. [DOI: 10.1089/ten.tea.2008.0602] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Oleg V. Semenov
- Department of Obstetrics, University Hospital Zurich, Zurich, Switzerland
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Antoine Malek
- Department of Obstetrics, University Hospital Zurich, Zurich, Switzerland
| | | | - Janos Vörös
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Andreas H. Zisch
- Department of Obstetrics, University Hospital Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, Zurich, Switzerland
- Department of Materials Science, Swiss Federal Institute of Technology, Zurich, Switzerland
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Milleret V, Simonet M, Bittermann AG, Neuenschwander P, Hall H. Cyto- and hemocompatibility of a biodegradable 3D-scaffold material designed for medical applications. J Biomed Mater Res B Appl Biomater 2009; 91:109-21. [DOI: 10.1002/jbm.b.31379] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Affiliation(s)
- Tessa Lühmann
- Department of Materials, ETH Zurich, Zurich, Switzerland, and ZMB, Center for Microscopy and Image Analysis, University of Zurich, Switzerland
| | - Markus Rimann
- Department of Materials, ETH Zurich, Zurich, Switzerland, and ZMB, Center for Microscopy and Image Analysis, University of Zurich, Switzerland
| | - Anne Greet Bittermann
- Department of Materials, ETH Zurich, Zurich, Switzerland, and ZMB, Center for Microscopy and Image Analysis, University of Zurich, Switzerland
| | - Heike Hall
- Department of Materials, ETH Zurich, Zurich, Switzerland, and ZMB, Center for Microscopy and Image Analysis, University of Zurich, Switzerland
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Tinguely M, Jenni B, Knights A, Lopes B, Korol D, Rousson V, Curioni Fontecedro A, Cogliatti SB, Bittermann AG, Schmid U, Dommann-Scherrer C, Maurer R, Renner C, Probst-Hensch NM, Moch H, Knuth A, Zippelius A. MAGE-C1/CT-7 expression in plasma cell myeloma: sub-cellular localization impacts on clinical outcome. Cancer Sci 2008; 99:720-5. [PMID: 18307538 DOI: 10.1111/j.1349-7006.2008.00738.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Plasma cell myelomas (PMs) have a poor prognosis. Cancer-testis (CT) antigens are immunogenic proteins, representing potential targets for tumor vaccination strategies. The expression of the CT antigens GAGE, MAGE-A4, MAGE-C1/CT-7, and NY-ESO-1 was investigated on paraffin-embedded bone marrow biopsies from 219 PM and 8 monoclonal gammopathy of undetermined significance (MGUS) patients. The frequency and prognostic impact of these CT antigens were compared with known morphological prognostic markers (i.e. Mib1 labeling index) and the presence of the translocations t(4;14)(p16.3; q32) and t(11;14)(q13;q32). We show that MAGE-C1/CT-7 is the most prevalent CT antigen, expressed in 57% of PMs in a high percentage of tumor cells. While MAGE-C1/CT-7 was absent in non-malignant plasma cells, plasma cells of patients with MGUS did express MAGE-C1/CT-7, but no other CT antigens. MAGE-C1/CT-7 was more frequently expressed in PMs with an elevated proliferation rate (Mib1 >10%) compared to PMs with a low proliferation rate (Mib1 <or=10%, 71%versus 29%, P < 0.001) and correlated with overall survival, depending on its subcellular distribution. PMs with pure cytoplasmic MAGE-C1/CT-7 expression showed a better prognosis (48 months versus 33 months, P < 0.05) than PMs with combined nuclear-cytoplasmic or nuclear expression only. Thus, expression of MAGE-C1/CT-7 in patients with monoclonal gammopathies represents a predictor of outcome and overt malignant transformation.
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Affiliation(s)
- M Tinguely
- Institute of Surgical Pathology, Department of Pathology, University Hospital Zurich, Zurich, Switzerland.
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Greve F, Frerker S, Bittermann AG, Burkhardt C, Hierlemann A, Hall H. Molecular design and characterization of the neuron-microelectrode array interface. Biomaterials 2007; 28:5246-58. [PMID: 17826828 DOI: 10.1016/j.biomaterials.2007.08.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 08/07/2007] [Indexed: 11/23/2022]
Abstract
Electrophysiological activities of neuronal networks can be recorded on microelectrode arrays (MEAs). This technique requires tight coupling between MEA-surfaces and cells. Therefore, this study investigated the interface between DRG neurons and MEA-surface materials after adsorption of neurite promoting proteins: laminin-111, fibronectin, L1Ig6 and poly-l-lysine. Moreover, substrate-induced effects on neuronal networks with time were analyzed. The thickness of adsorbed protein layers was found between approximately 1 nm for poly-l-lysine and approximately 80 nm for laminin-111 on platinum, gold and silicon nitride. The neuron-to-substrate interface was characterized by Scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and SEM after in situ focused-ion-beam milling demonstrating that the ventral cell membrane adhered inhomogeneously to laminin-111 or L1Ig6 surfaces. Tight areas of 20-30 nm and distant areas <1 microm alternated and even tightest areas did not correlate with the physical thickness of the protein layers. This study illustrates the difficulties to predict cell-to-material interfaces that contribute substantially to the success of in vitro or in vivo systems. Moreover, focused ion beam (FIB)/SEM is explored as a new technique to analyze such interfaces.
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Affiliation(s)
- Frauke Greve
- Physics Electronics Laboratory, Department of Physics, ETH Zurich, Switzerland
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Bilic G, Hall H, Bittermann AG, Zammeretti P, Burkhart T, Ochsenbein-Kölble N, Zimmermann R. Human preterm amnion cells cultured in 3-dimensional collagen I and fibrin matrices for tissue engineering purposes. Am J Obstet Gynecol 2005; 193:1724-32. [PMID: 16260217 DOI: 10.1016/j.ajog.2005.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 03/07/2005] [Accepted: 04/01/2005] [Indexed: 11/29/2022]
Abstract
OBJECTIVE In this study, human preterm amnion cells were investigated in 3-dimensional (3D) cell-matrix culture systems in an attempt to design therapeutic strategies for preterm premature rupture of the membranes. STUDY DESIGN Three-dimensional collagen I and fibrin cell-containing biomatrices were created to mimic the architecture of native amnion. Amnion mesenchymal cells were embedded in 3D matrices, and epithelial cells were placed on top of these matrices. Cell viability and morphology were visualized by DiI-ac-LDL, F-actin, and nuclear staining. Proteolytic activity of matrix metalloproteinases (MMPs) was investigated using gelatine zymography. RESULTS Preterm amnion epithelial and mesenchymal cells cultured in collagen I and fibrin matrices assume cell morphologies similar to those observed in vivo. Mesenchymal cells were capable of remodelling collagen I, as seen by extensive volume contraction, by 40% at day 1 and 80% at day 5. Matrix contraction was independent of the presence of epithelial cells, and could not be inhibited by GM6001 and/or aprotinin. No contraction was observed in fibrin matrices over 8 days. The migratory response of mesenchymal cells cultured in 3D fibrin matrices supplemented with fibronectin was associated with specific activated MMP-9. CONCLUSION Three-dimensional fibrin matrices might be useful in amnion cell tissue engineering, including cell-matrix transplantation.
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Affiliation(s)
- Grozdana Bilic
- Department of Obstetrics, Zurich University Hospital, Zurich, Switzerland
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Urech L, Bittermann AG, Hubbell JA, Hall H. Mechanical properties, proteolytic degradability and biological modifications affect angiogenic process extension into native and modified fibrin matrices in vitro. Biomaterials 2005; 26:1369-79. [PMID: 15482824 DOI: 10.1016/j.biomaterials.2004.04.045] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Accepted: 04/30/2004] [Indexed: 01/17/2023]
Abstract
During initial stages of wound healing, fibrin clots provide a three-dimensional scaffold that induces cell infiltration and regeneration. Here, L1Ig6, a ligand for alphavbeta3 integrin was covalently incorporated within fibrin matrices to explore it as a matrix-immobilized angiogenic factor. Incorporation at concentrations greater than 1 microg/ml reduced the fibrin crosslink density, as reflected by measurements of elastic modulus and swelling. The influence of crosslink density on endothelial cell process extension was characterized by modulating factor XIII concentrations in the coagulation mixture. At low incorporated concentrations of L1Ig6, it was possible to compensate gel elastic modulus via increased factor XIII, but not at high concentrations of L1Ig6. Similar findings were found when matrix swelling was analyzed. Fibrin crosslink density strongly influenced endothelial cell process extension, fewer and shorter processes were observed at high crosslink density. Matrix metalloproteinases (MMPs) were required for process extension and zymography and Western blots identified MMP-2 but not MMP-9. The amount of active MMP-2 increased for endothelial cells cultured in native and L1Ig6-modified matrices or when stimulated with VEGF-A165. The data indicate that distinct matrix properties can be tailored such that they become biologically stimulating and respond to cellular proteolytic activities, being a prerequisite for potential use of such matrices in biomedical applications.
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Affiliation(s)
- Lukas Urech
- Department of Material Sciences, Institute for Biomedical Engineering, Federal Institute of Technology and University of Zurich, Moussonstrasse 18, CH-8044 Zurich, Switzerland
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Bilic G, Hall H, Bittermann AG, Burkhardt T, Zammaretti P, Ochsenbein N, Zimmermann R. Study of human amnion cells outgrowth in three-dimensional Collagen I and Fibrin matrices for the treatment of PPROM. Z Geburtshilfe Neonatol 2005. [DOI: 10.1055/s-2005-923244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Fraefel C, Bittermann AG, Büeler H, Heid I, Bächi T, Ackermann M. Spatial and temporal organization of adeno-associated virus DNA replication in live cells. J Virol 2004; 78:389-98. [PMID: 14671120 PMCID: PMC303420 DOI: 10.1128/jvi.78.1.389-398.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Accepted: 09/16/2003] [Indexed: 11/20/2022] Open
Abstract
Upon cell entry, the genomes of herpes simplex virus type 1 (HSV-1) and adenovirus (Ad) associate with distinct nuclear structures termed ND10 or promyelocytic leukemia (PML) nuclear bodies (NBs). PML NB morphology is altered or disrupted by specific viral proteins as replication proceeds. We examined whether adeno-associated virus (AAV) replication compartments also associate with PML NBs, and whether modification or disruption of these by HSV-1 or Ad, both of which are helper viruses for AAV, is necessary at all. Furthermore, to add a fourth dimension to our present view of AAV replication, we established an assay that allows visualization of AAV replication in live cells. A recombinant AAV containing 40 lac repressor binding sites between the AAV inverted terminal repeats was constructed. AAV Rep protein and helper virus-mediated replication of this recombinant AAV genome was visualized by binding of enhanced yellow fluorescent protein-lac repressor fusion protein to double-stranded AAV replication intermediates. We demonstrate in live cells that AAV DNA replication occurs in compartments which colocalize with AAV Rep. Early after infection, the replication compartments were small and varied in numbers from 2 to more than 40 per cell nucleus. Within 4 to 8 h, individual small replication compartments expanded and fused to larger structures which filled out much of the cell nucleus. We also show that AAV replication compartments can associate with modified PML NBs in Ad-infected cells. In wild-type HSV-1-infected cells, AAV replication compartments and PML NBs did not coexist, presumably because PML was completely disrupted by the HSV-1 ICP0 protein. However, alteration or disruption of PML appears not to be a prerequisite for AAV replication, as the formation of replication compartments was normal when the ICP0 mutants HSV-1 dl1403 and HSV-1 FXE, which do not affect PML NBs, were used as the helper viruses; under these conditions, AAV replication compartments did not associate with PML NBs.
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Affiliation(s)
- Cornel Fraefel
- Institute of Virology, University of Zurich, Zurich, Switzerland.
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Bittermann AG, Knoll G, Németh A, Plattner H. Quantitative immuno-gold labelling and ultrastructural preservation after cryofixation (combined with different freeze-substitution and embedding protocols) and after chemical fixation and cryosectioning. Analysis of the secretory organelle matrix of Paramecium trichocysts. Histochemistry 1992; 97:421-9. [PMID: 1500298 DOI: 10.1007/bf00270389] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Among the variety of parameters affecting immuno-gold labelling efficiency, mainly the effects of different preparative protocols were tested. Preservation of ultrastructure and of antigenicity are the salient features of this study. We have labelled insoluble components of the secretory matrix of Paramecium trichocysts with specific antisera, using 10 nm colloidal gold particles. The highest labelling efficiency was obtained with fast freezing (cryofixation, either by sandwich or spray-freezing), freeze-substitution in methanol (without added fixatives) and hydrophilic Lowicryls, particularly when applied at low temperatures (K11M at 193 K). The presence of different chemical fixatives always reduced the labelling density and some recommendations from the literature do not appear advisable. Methods commencing with fixation at greater than or equal to 0 degree C, such as "progressive lowering of temperature" (PLT) or preparation of cryostat sections, i.e. with chemical pretreatments, always resulted in lower labelling density. Our data appear, therefore, relevant for optimal immuno-gold labelling of insoluble antigens and emphasize the potential of cryofixation as a primary preparation step. In addition, ultrastructural preservation was also superior after cryofixation.
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Affiliation(s)
- A G Bittermann
- Faculty of Biology, University of Konstanz, Federal Republic of Germany
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