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Bogolyubov DS, Shabelnikov SV, Travina AO, Sulatsky MI, Bogolyubova IO. Special Nuclear Structures in the Germinal Vesicle of the Common Frog with Emphasis on the So-Called Karyosphere Capsule. J Dev Biol 2023; 11:44. [PMID: 38132712 PMCID: PMC10744300 DOI: 10.3390/jdb11040044] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 12/23/2023] Open
Abstract
The karyosphere (karyosome) is a structure that forms in the oocyte nucleus-germinal vesicle (GV)-at the diplotene stage of meiotic prophase due to the assembly of all chromosomes in a limited portion of the GV. In some organisms, the karyosphere has an extrachromosomal external capsule, the marker protein of which is nuclear F-actin. Despite many years of theories about the formation of the karyosphere capsule (KC) in the GV of the common frog Rana temporaria, we present data that cast doubt on its existence, at least in this species. Specific extrachromosomal strands, which had been considered the main elements of the frog's KC, do not form a continuous layer around the karyosphere and, according to immunogold labeling, do not contain structural proteins, such as actin and lamin B. At the same time, F-actin is indeed noticeably concentrated around the karyosphere, creating the illusion of a capsule at the light microscopy/fluorescence level. The barrier-to-autointegration factor (BAF) and one of its functional partners-LEMD2, an inner nuclear membrane protein-are not localized in the strands, suggesting that the strands are not functional counterparts of the nuclear envelope. The presence of characteristic strands in the GV of R. temporaria late oocytes may reflect an excess of SMC1 involved in the structural maintenance of diplotene oocyte chromosomes at the karyosphere stage, since SMC1 has been shown to be the most abundant protein in the strands. Other characteristic microstructures-the so-called annuli, very similar in ultrastructure to the nuclear pore complexes-do not contain nucleoporins Nup35 and Nup93, and, therefore, they cannot be considered autonomous pore complexes, as previously thought. Taken together, our data indicate that traditional ideas about the existence of the R. temporaria KC as a special structural compartment of the GV are to be revisited.
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Affiliation(s)
- Dmitry S. Bogolyubov
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia; (S.V.S.); (A.O.T.); (M.I.S.); (I.O.B.)
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Edginton-White B, Bonifer C. The transcriptional regulation of normal and malignant blood cell development. FEBS J 2021; 289:1240-1255. [PMID: 33511785 DOI: 10.1111/febs.15735] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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: 11/30/2020] [Revised: 01/11/2021] [Accepted: 01/26/2021] [Indexed: 11/27/2022]
Abstract
Development of multicellular organisms requires the differential usage of our genetic information to change one cell fate into another. This process drives the appearance of different cell types that come together to form specialized tissues sustaining a healthy organism. In the last decade, by moving away from studying single genes toward a global view of gene expression control, a revolution has taken place in our understanding of how genes work together and how cells communicate to translate the information encoded in the genome into a body plan. The development of hematopoietic cells has long served as a paradigm of development in general. In this review, we highlight how transcription factors and chromatin components work together to shape the gene regulatory networks controlling gene expression in the hematopoietic system and to drive blood cell differentiation. In addition, we outline how this process goes astray in blood cancers. We also touch upon emerging concepts that place these processes firmly into their associated subnuclear structures adding another layer of the control of differential gene expression.
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Affiliation(s)
- Benjamin Edginton-White
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, UK
| | - Constanze Bonifer
- Institute of Cancer and Genomic Sciences, College of Medicine and Dentistry, University of Birmingham, UK
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Muller H, Gil J Jr, Drinnenberg IA. The Impact of Centromeres on Spatial Genome Architecture. Trends Genet 2019; 35:565-78. [PMID: 31200946 DOI: 10.1016/j.tig.2019.05.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/06/2019] [Accepted: 05/09/2019] [Indexed: 01/01/2023]
Abstract
The development of new technologies and experimental techniques is enabling researchers to see what was once unable to be seen. For example, the centromere was first seen as the mediator between spindle fiber and chromosome during mitosis and meiosis. Although this continues to be its most prominent role, we now know that the centromere functions beyond cellular division with important roles in genome organization and chromatin regulation. Here we aim to share the structures and functions of centromeres in various organisms beginning with the diversity of their DNA sequence anatomies. We zoom out to describe their position in the nucleus and ultimately detail the different ways they contribute to genome organization and regulation at the spatial level.
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Abstract
Pooled-library CRISPR screening provides a powerful means to discover genetic factors involved in cellular processes in a high-throughput manner. However, the phenotypes accessible to pooled-library screening are limited. Complex phenotypes, such as cellular morphology and subcellular molecular organization, as well as their dynamics, require imaging-based readout and are currently beyond the reach of pooled-library CRISPR screening. Here we report an all imaging-based pooled-library CRISPR screening approach that combines high-content phenotype imaging with high-throughput single guide RNA (sgRNA) identification in individual cells. In this approach, sgRNAs are codelivered to cells with corresponding barcodes placed at the 3' untranslated region of a reporter gene using a lentiviral delivery system with reduced recombination-induced sgRNA-barcode mispairing. Multiplexed error-robust fluorescence in situ hybridization (MERFISH) is used to read out the barcodes and hence identify the sgRNAs with high accuracy. We used this approach to screen 162 sgRNAs targeting 54 RNA-binding proteins for their effects on RNA localization to nuclear compartments and uncovered previously unknown regulatory factors for nuclear RNA localization. Notably, our screen revealed both positive and negative regulators for the nuclear speckle localization of a long noncoding RNA, MALAT1, suggesting a dynamic regulation of lncRNA localization in subcellular compartments.
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MESH Headings
- CRISPR-Cas Systems/genetics
- Cell Line, Tumor
- Cell Nucleus/chemistry
- Cell Nucleus/metabolism
- Gene Editing
- High-Throughput Nucleotide Sequencing/methods
- Humans
- Image Processing, Computer-Assisted/methods
- In Situ Hybridization, Fluorescence/methods
- Molecular Probes/chemistry
- Molecular Probes/genetics
- Molecular Probes/metabolism
- RNA, Guide, CRISPR-Cas Systems/chemistry
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- RNA, Long Noncoding/chemistry
- RNA, Long Noncoding/genetics
- RNA, Long Noncoding/metabolism
- RNA-Binding Proteins/chemistry
- RNA-Binding Proteins/metabolism
- Single-Cell Analysis/methods
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Affiliation(s)
- Chong Wang
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Department of Physics, Harvard University, Cambridge, MA 02138
| | - Tian Lu
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Department of Physics, Harvard University, Cambridge, MA 02138
| | - George Emanuel
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Department of Physics, Harvard University, Cambridge, MA 02138
| | - Hazen P Babcock
- Center for Advanced Imaging, Harvard University, Cambridge, MA 02138
| | - Xiaowei Zhuang
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138;
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Department of Physics, Harvard University, Cambridge, MA 02138
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5
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Abstract
Chromosomes are folded and compacted in interphase nuclei, but the molecular basis of this folding is poorly understood. Chromosome conformation capture methods, such as Hi-C, combine chemical crosslinking of chromatin with fragmentation, DNA ligation, and high-throughput DNA sequencing to detect neighboring loci genome-wide. Hi-C has revealed the segregation of chromatin into active and inactive compartments and the folding of DNA into self-associating domains and loops. Depletion of CTCF, cohesin, or cohesin-associated proteins was recently shown to affect the majority of domains and loops in a manner that is consistent with a model of DNA folding through extrusion of chromatin loops. Compartmentation was not dependent on CTCF or cohesin. Hi-C contact maps represent the superimposition of CTCF/cohesin-dependent and -independent folding states.
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Affiliation(s)
- Kyle P Eagen
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Rao SSP, Huang SC, Glenn St Hilaire B, Engreitz JM, Perez EM, Kieffer-Kwon KR, Sanborn AL, Johnstone SE, Bascom GD, Bochkov ID, Huang X, Shamim MS, Shin J, Turner D, Ye Z, Omer AD, Robinson JT, Schlick T, Bernstein BE, Casellas R, Lander ES, Aiden EL. Cohesin Loss Eliminates All Loop Domains. Cell 2017; 171:305-320.e24. [PMID: 28985562 PMCID: PMC5846482 DOI: 10.1016/j.cell.2017.09.026] [Citation(s) in RCA: 1040] [Impact Index Per Article: 148.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 08/02/2017] [Accepted: 09/18/2017] [Indexed: 01/12/2023]
Abstract
The human genome folds to create thousands of intervals, called "contact domains," that exhibit enhanced contact frequency within themselves. "Loop domains" form because of tethering between two loci-almost always bound by CTCF and cohesin-lying on the same chromosome. "Compartment domains" form when genomic intervals with similar histone marks co-segregate. Here, we explore the effects of degrading cohesin. All loop domains are eliminated, but neither compartment domains nor histone marks are affected. Loss of loop domains does not lead to widespread ectopic gene activation but does affect a significant minority of active genes. In particular, cohesin loss causes superenhancers to co-localize, forming hundreds of links within and across chromosomes and affecting the regulation of nearby genes. We then restore cohesin and monitor the re-formation of each loop. Although re-formation rates vary greatly, many megabase-sized loops recovered in under an hour, consistent with a model where loop extrusion is rapid.
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Affiliation(s)
- Suhas S P Rao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Su-Chen Huang
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Brian Glenn St Hilaire
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA
| | | | | | | | - Adrian L Sanborn
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA; Department of Computer Science, Stanford University, Stanford, CA 94305, USA
| | - Sarah E Johnstone
- Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Gavin D Bascom
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Ivan D Bochkov
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xingfan Huang
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX 77030, USA
| | - Muhammad S Shamim
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX 77030, USA; Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jaeweon Shin
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX 77030, USA
| | - Douglass Turner
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Ziyi Ye
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX 77030, USA
| | - Arina D Omer
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - James T Robinson
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Department of Medicine, University of California, San Diego, La Jolla, CA 92037, USA
| | - Tamar Schlick
- Department of Chemistry, New York University, New York, NY 10003, USA; Courant Institute of Mathematical Sciences, New York University, New York, NY 10012, USA; NYU-ECNU Center for Computational Chemistry, NYU Shanghai, Shanghai 200062, China
| | - Bradley E Bernstein
- Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Department of Pathology and Center for Cancer Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Rafael Casellas
- Lymphocyte Nuclear Biology, NIAMS, NIH, Bethesda, MD 20892, USA; Center of Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Eric S Lander
- Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Department of Biology, MIT, Cambridge, MA 02139, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Erez Lieberman Aiden
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Center for Theoretical Biological Physics, Rice University, Houston, TX 77030, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX 77030, USA.
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Brant L, Georgomanolis T, Nikolic M, Brackley CA, Kolovos P, van Ijcken W, Grosveld FG, Marenduzzo D, Papantonis A. Exploiting native forces to capture chromosome conformation in mammalian cell nuclei. Mol Syst Biol 2016; 12:891. [PMID: 27940490 PMCID: PMC5199122 DOI: 10.15252/msb.20167311] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mammalian interphase chromosomes fold into a multitude of loops to fit the confines of cell nuclei, and looping is tightly linked to regulated function. Chromosome conformation capture (3C) technology has significantly advanced our understanding of this structure‐to‐function relationship. However, all 3C‐based methods rely on chemical cross‐linking to stabilize spatial interactions. This step remains a “black box” as regards the biases it may introduce, and some discrepancies between microscopy and 3C studies have now been reported. To address these concerns, we developed “i3C”, a novel approach for capturing spatial interactions without a need for cross‐linking. We apply i3C to intact nuclei of living cells and exploit native forces that stabilize chromatin folding. Using different cell types and loci, computational modeling, and a methylation‐based orthogonal validation method, “TALE‐iD”, we show that native interactions resemble cross‐linked ones, but display improved signal‐to‐noise ratios and are more focal on regulatory elements and CTCF sites, while strictly abiding to topologically associating domain restrictions.
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Affiliation(s)
- Lilija Brant
- Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | | | - Milos Nikolic
- Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Chris A Brackley
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
| | - Petros Kolovos
- Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Frank G Grosveld
- Department of Cell Biology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Davide Marenduzzo
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
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8
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Abstract
Trans-inactivation is the repression of genes on a normal chromosome under the influence of a rearranged homologous chromosome demonstrating the position effect variegation (PEV). This phenomenon was studied in detail on the example of brownDominant allele causing the repression of wild-type brown gene on the opposite chromosome. We have investigated another trans-inactivation-inducing chromosome rearrangement, In(2)A4 inversion. In both cases, brownDominant and In(2)A4, the repression seems to be the result of dragging of the euchromatic region of the normal chromosome into the heterochromatic environment. It was found that cis-inactivation (classical PEV) and trans-inactivation show different patterns of distribution along the chromosome and respond differently to PEV modifying genes. It appears that the causative mechanism of trans-inactivation is de novo heterochromatin assembly on euchromatic sequences dragged into the heterochromatic nuclear compartment. Trans-inactivation turns out to be the result of a combination of heterochromatin-induced position effect and the somatic interphase chromosome pairing that is widespread in Diptera.
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Affiliation(s)
- Aleksei S Shatskikh
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
| | - Yuriy A Abramov
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
| | - Sergey A Lavrov
- a Department of Molecular Genetics of the Cell , Institute of Molecular Genetics, Russian Academy of Science , Moscow , Russia
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Weston DJ, Russell RA, Batty E, Jensen K, Stephens DA, Adams NM, Freemont PS. New quantitative approaches reveal the spatial preference of nuclear compartments in mammalian fibroblasts. J R Soc Interface 2015; 12:20140894. [PMID: 25631564 PMCID: PMC4345468 DOI: 10.1098/rsif.2014.0894] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The nuclei of higher eukaryotic cells display compartmentalization and certain nuclear compartments have been shown to follow a degree of spatial organization. To date, the study of nuclear organization has often involved simple quantitative procedures that struggle with both the irregularity of the nuclear boundary and the problem of handling replicate images. Such studies typically focus on inter-object distance, rather than spatial location within the nucleus. The concern of this paper is the spatial preference of nuclear compartments, for which we have developed statistical tools to quantitatively study and explore nuclear organization. These tools combine replicate images to generate 'aggregate maps' which represent the spatial preferences of nuclear compartments. We present two examples of different compartments in mammalian fibroblasts (WI-38 and MRC-5) that demonstrate new knowledge of spatial preference within the cell nucleus. Specifically, the spatial preference of RNA polymerase II is preserved across normal and immortalized cells, whereas PML nuclear bodies exhibit a change in spatial preference from avoiding the centre in normal cells to exhibiting a preference for the centre in immortalized cells. In addition, we show that SC35 splicing speckles are excluded from the nuclear boundary and localize throughout the nucleoplasm and in the interchromatin space in non-transformed WI-38 cells. This new methodology is thus able to reveal the effect of large-scale perturbation on spatial architecture and preferences that would not be obvious from single cell imaging.
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Affiliation(s)
- David J Weston
- Department of Computer Science and Information Systems, Birkbeck College, University of London, London, UK
| | - Richard A Russell
- Department of Optometry and Visual Science, City University London, London, UK
| | - Elizabeth Batty
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington, London, UK
| | - Kirsten Jensen
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington, London, UK
| | - David A Stephens
- Department of Mathematics and Statistics, McGill University, Montreal, Québec, Canada
| | - Niall M Adams
- Department of Mathematics, Imperial College London, South Kensington, London, UK Heilbronn Institute for Mathematical Research, University of Bristol, Bristol, UK
| | - Paul S Freemont
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington, London, UK
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Abstract
The dynamic ability of genomes to interact with discrete nuclear compartments appears to be essential for chromatin function. However, the extent to which structural nuclear proteins contribute to this level of organization is largely unresolved. To test the links between structure and function, we evaluated how nuclear lamins contribute to the organization of a major functional compartment, the nucleolus. HeLa cells with compromised expression of the genes encoding lamins were analyzed using high-resolution imaging and pull-down assays. When lamin B1 expression was depleted, inhibition of RNA synthesis correlated with complex structural changes within the nucleolar active centers until, eventually, the nucleoli were dispersed completely. With normal lamin expression, the nucleoli were highly plastic, with dramatic and freely reversible structural changes correlating with the demand for ribosome biogenesis. Preservation of the nucleolar compartment throughout these structural transitions is shown to be linked to lamin B1 expression, with the lamin B1 protein interacting with the major nucleolar protein nucleophosmin/B23.
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Affiliation(s)
- Catherine Martin
- Faculty of Life Sciences, University of Manchester, MIB, 131 Princess Street, Manchester M1 7DN, UK
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Sadoni N, Langer S, Fauth C, Bernardi G, Cremer T, Turner BM, Zink D. Nuclear organization of mammalian genomes. Polar chromosome territories build up functionally distinct higher order compartments. J Cell Biol 1999; 146:1211-26. [PMID: 10491386 PMCID: PMC2156120 DOI: 10.1083/jcb.146.6.1211] [Citation(s) in RCA: 224] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We investigated the nuclear higher order compartmentalization of chromatin according to its replication timing (Ferreira et al. 1997) and the relations of this compartmentalization to chromosome structure and the spatial organization of transcription. Our aim was to provide a comprehensive and integrated view on the relations between chromosome structure and functional nuclear architecture. Using different mammalian cell types, we show that distinct higher order compartments whose DNA displays a specific replication timing are stably maintained during all interphase stages. The organizational principle is clonally inherited. We directly demonstrate the presence of polar chromosome territories that align to build up higher order compartments, as previously suggested (Ferreira et al. 1997). Polar chromosome territories display a specific orientation of early and late replicating subregions that correspond to R- or G/C-bands of mitotic chromosomes. Higher order compartments containing G/C-bands replicating during the second half of the S phase display no transcriptional activity detectable by BrUTP pulse labeling and show no evidence of transcriptional competence. Transcriptionally competent and active chromatin is confined to a coherent compartment within the nuclear interior that comprises early replicating R-band sequences. As a whole, the data provide an integrated view on chromosome structure, nuclear higher order compartmentalization, and their relation to the spatial organization of functional nuclear processes.
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Affiliation(s)
- Nicolas Sadoni
- Institut für Anthropologie und Humangenetik, LMU München, 80336 München, Germany
| | - Sabine Langer
- Institut für Anthropologie und Humangenetik, LMU München, 80336 München, Germany
| | - Christine Fauth
- Institut für Anthropologie und Humangenetik, LMU München, 80336 München, Germany
| | | | - Thomas Cremer
- Institut für Anthropologie und Humangenetik, LMU München, 80333 München, Germany
| | - Bryan M. Turner
- Chromatin and Gene Expression Group, Department of Anatomy, University of Birmingham Medical School, Birmingham B15 2TT, United Kingdom
| | - Daniele Zink
- Institut für Anthropologie und Humangenetik, LMU München, 80336 München, Germany
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