1
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Garate X, Gómez-García PA, Merino MF, Angles MC, Zhu C, Castells-García A, Ed-Daoui I, Martin L, Ochiai H, Neguembor MV, Cosma MP. The relationship between nanoscale genome organization and gene expression in mouse embryonic stem cells during pluripotency transition. Nucleic Acids Res 2024; 52:8146-8164. [PMID: 38850157 DOI: 10.1093/nar/gkae476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/16/2024] [Accepted: 06/05/2024] [Indexed: 06/10/2024] Open
Abstract
During early development, gene expression is tightly regulated. However, how genome organization controls gene expression during the transition from naïve embryonic stem cells to epiblast stem cells is still poorly understood. Using single-molecule microscopy approaches to reach nanoscale resolution, we show that genome remodeling affects gene transcription during pluripotency transition. Specifically, after exit from the naïve pluripotency state, chromatin becomes less compacted, and the OCT4 transcription factor has lower mobility and is more bound to its cognate sites. In epiblast cells, the active transcription hallmark, H3K9ac, decreases within the Oct4 locus, correlating with reduced accessibility of OCT4 and, in turn, with reduced expression of Oct4 nascent RNAs. Despite the high variability in the distances between active pluripotency genes, distances between Nodal and Oct4 decrease during epiblast specification. In particular, highly expressed Oct4 alleles are closer to nuclear speckles during all stages of the pluripotency transition, while only a distinct group of highly expressed Nodal alleles are in close proximity to Oct4 when associated with a nuclear speckle in epiblast cells. Overall, our results provide new insights into the role of the spatiotemporal genome remodeling during mouse pluripotency transition and its correlation with the expression of key pluripotency genes.
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Affiliation(s)
- Ximena Garate
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Manuel Fernández Merino
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Marta Cadevall Angles
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Chenggan Zhu
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Alvaro Castells-García
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Ilyas Ed-Daoui
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
| | - Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Hiroshi Ochiai
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, 106 Zhongshan Er Road, Yuexiu district, 510080 Guangzhou, China
- ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
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2
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Ochs F, Green C, Szczurek AT, Pytowski L, Kolesnikova S, Brown J, Gerlich DW, Buckle V, Schermelleh L, Nasmyth KA. Sister chromatid cohesion is mediated by individual cohesin complexes. Science 2024; 383:1122-1130. [PMID: 38452070 DOI: 10.1126/science.adl4606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024]
Abstract
Eukaryotic genomes are organized by loop extrusion and sister chromatid cohesion, both mediated by the multimeric cohesin protein complex. Understanding how cohesin holds sister DNAs together, and how loss of cohesion causes age-related infertility in females, requires knowledge as to cohesin's stoichiometry in vivo. Using quantitative super-resolution imaging, we identified two discrete populations of chromatin-bound cohesin in postreplicative human cells. Whereas most complexes appear dimeric, cohesin that localized to sites of sister chromatid cohesion and associated with sororin was exclusively monomeric. The monomeric stoichiometry of sororin:cohesin complexes demonstrates that sister chromatid cohesion is conferred by individual cohesin rings, a key prediction of the proposal that cohesion arises from the co-entrapment of sister DNAs.
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Affiliation(s)
- Fena Ochs
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Charlotte Green
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | | | - Lior Pytowski
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Sofia Kolesnikova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna Austria
| | - Jill Brown
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Daniel Wolfram Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna Austria
| | - Veronica Buckle
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
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3
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Spitzer H, Berry S, Donoghoe M, Pelkmans L, Theis FJ. Learning consistent subcellular landmarks to quantify changes in multiplexed protein maps. Nat Methods 2023:10.1038/s41592-023-01894-z. [PMID: 37248388 PMCID: PMC10333128 DOI: 10.1038/s41592-023-01894-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 04/25/2023] [Indexed: 05/31/2023]
Abstract
Highly multiplexed imaging holds enormous promise for understanding how spatial context shapes the activity of the genome and its products at multiple length scales. Here, we introduce a deep learning framework called CAMPA (Conditional Autoencoder for Multiplexed Pixel Analysis), which uses a conditional variational autoencoder to learn representations of molecular pixel profiles that are consistent across heterogeneous cell populations and experimental perturbations. Clustering these pixel-level representations identifies consistent subcellular landmarks, which can be quantitatively compared in terms of their size, shape, molecular composition and relative spatial organization. Using high-resolution multiplexed immunofluorescence, this reveals how subcellular organization changes upon perturbation of RNA synthesis, RNA processing or cell size, and uncovers links between the molecular composition of membraneless organelles and cell-to-cell variability in bulk RNA synthesis rates. By capturing interpretable cellular phenotypes, we anticipate that CAMPA will greatly accelerate the systematic mapping of multiscale atlases of biological organization to identify the rules by which context shapes physiology and disease.
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Affiliation(s)
- Hannah Spitzer
- Institute of Computational Biology, Helmholtz Center Munich, Munich, Germany
| | - Scott Berry
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- EMBL Australia Node in Single Molecule Science, School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Mark Donoghoe
- Stats Central, Mark Wainwright Analytical Centre, University of New South Wales, Sydney, New South Wales, Australia
| | - Lucas Pelkmans
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
| | - Fabian J Theis
- Institute of Computational Biology, Helmholtz Center Munich, Munich, Germany.
- School of Computation, Information and Technology CIT, Technical University of Munich, Munich, Germany.
- TUM School of Life Sciences Weihenstephan, Technical University of Munich, Munich, Germany.
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4
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Jeziorska DM, Tunnacliffe EAJ, Brown JM, Ayyub H, Sloane-Stanley J, Sharpe JA, Lagerholm BC, Babbs C, Smith AJH, Buckle VJ, Higgs DR. On-microscope staging of live cells reveals changes in the dynamics of transcriptional bursting during differentiation. Nat Commun 2022; 13:6641. [PMID: 36333299 PMCID: PMC9636426 DOI: 10.1038/s41467-022-33977-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Determining the mechanisms by which genes are switched on and off during development is a key aim of current biomedical research. Gene transcription has been widely observed to occur in a discontinuous fashion, with short bursts of activity interspersed with periods of inactivity. It is currently not known if or how this dynamic behaviour changes as mammalian cells differentiate. To investigate this, using an on-microscope analysis, we monitored mouse α-globin transcription in live cells throughout erythropoiesis. We find that changes in the overall levels of α-globin transcription are most closely associated with changes in the fraction of time a gene spends in the active transcriptional state. We identify differences in the patterns of transcriptional bursting throughout differentiation, with maximal transcriptional activity occurring in the mid-phase of differentiation. Early in differentiation, we observe increased fluctuation in transcriptional activity whereas at the peak of gene expression, in early erythroblasts, transcription is relatively stable. Later during differentiation as α-globin expression declines, we again observe more variability in transcription within individual cells. We propose that the observed changes in transcriptional behaviour may reflect changes in the stability of active transcriptional compartments as gene expression is regulated during differentiation.
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Affiliation(s)
- D. M. Jeziorska
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK ,Present Address: Nucleome Therapeutics Ltd., BioEscalator, The Innovation Building, Old Road Campus, Oxford, OX3 7FZ UK
| | - E. A. J. Tunnacliffe
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - J. M. Brown
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - H. Ayyub
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - J. Sloane-Stanley
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - J. A. Sharpe
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - B. C. Lagerholm
- grid.4991.50000 0004 1936 8948Wolfson Imaging Centre, MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK ,grid.4991.50000 0004 1936 8948Present Address: The Kennedy Institute Of Rheumatology, University of Oxford, Old Road Campus, Oxford, OX3 7FY UK
| | - C. Babbs
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - A. J. H. Smith
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK ,grid.4305.20000 0004 1936 7988Present Address: MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, EH16 4UU UK
| | - V. J. Buckle
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK
| | - D. R. Higgs
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute for Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS UK ,grid.4991.50000 0004 1936 8948Chinese Academy of Medical Sciences Oxford Institute, Nuffield Department of Medicine, University of Oxford, Old Road Campus, Oxford, OX3 7BN UK
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5
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Faber GP, Nadav-Eliyahu S, Shav-Tal Y. Nuclear speckles - a driving force in gene expression. J Cell Sci 2022; 135:275909. [PMID: 35788677 DOI: 10.1242/jcs.259594] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nuclear speckles are dynamic membraneless bodies located in the cell nucleus. They harbor RNAs and proteins, many of which are splicing factors, that together display complex biophysical properties dictating nuclear speckle formation and maintenance. Although these nuclear bodies were discovered decades ago, only recently has in-depth genomic analysis begun to unravel their essential functions in modulation of gene activity. Major advancements in genomic mapping techniques combined with microscopy approaches have enabled insights into the roles nuclear speckles may play in enhancing gene expression, and how gene positioning to specific nuclear landmarks can regulate gene expression and RNA processing. Some studies have drawn a link between nuclear speckles and disease. Certain maladies either involve nuclear speckles directly or dictate the localization and reorganization of many nuclear speckle factors. This is most striking during viral infection, as viruses alter the entire nuclear architecture and highjack host machinery. As discussed in this Review, nuclear speckles represent a fascinating target of study not only to reveal the links between gene positioning, genome subcompartments and gene activity, but also as a potential target for therapeutics.
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Affiliation(s)
- Gabriel P Faber
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Shani Nadav-Eliyahu
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
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6
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Scott C, Downes DJ, Brown JM, Beagrie R, Olijnik AA, Gosden M, Schwessinger R, Fisher CA, Rose A, Ferguson DJP, Johnson E, Hill QA, Okoli S, Renella R, Ryan K, Brand M, Hughes J, Roy NBA, Higgs DR, Babbs C, Buckle VJ. Recapitulation of erythropoiesis in congenital dyserythropoietic anaemia type I (CDA-I) identifies defects in differentiation and nucleolar abnormalities. Haematologica 2021; 106:2960-2970. [PMID: 33121234 PMCID: PMC8561284 DOI: 10.3324/haematol.2020.260158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/17/2020] [Indexed: 11/19/2022] Open
Abstract
The investigation of inherited disorders of erythropoiesis has elucidated many of the principles underlying the production of normal red blood cells and how this is perturbed in human disease. Congenital Dyserythropoietic Anaemia type 1 (CDA-I) is a rare form of anaemia caused by mutations in two genes of unknown function: CDAN1 and CDIN1 (previously called C15orf41), whilst in some cases, the underlying genetic abnormality is completely unknown. Consequently, the pathways affected in CDA-I remain to be discovered. To enable detailed analysis of this rare disorder we have validated a culture system which recapitulates all of the cardinal haematological features of CDA-I, including the formation of the pathognomonic 'spongy' heterochromatin seen by electron microscopy. Using a variety of cell and molecular biological approaches we discovered that erythroid cells in this condition show a delay during terminal erythroid differentiation, associated with increased proliferation and widespread changes in chromatin accessibility. We also show that the proteins encoded by CDAN1 and CDIN1 are enriched in nucleoli which are structurally and functionally abnormal in CDA-I. Together these findings provide important pointers to the pathways affected in CDA-I which for the first time can now be pursued in the tractable culture system utilised here.
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Affiliation(s)
- Caroline Scott
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford.
| | - Damien J Downes
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Jill M Brown
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Robert Beagrie
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | | | - Matthew Gosden
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Ron Schwessinger
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | | | - Anna Rose
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - David J P Ferguson
- Ultrastructural Morphology Group, NDCLS, John Radcliffe Hospital, Oxford
| | - Errin Johnson
- Sir William Dunn School of Pathology, Oxford University, Oxford
| | | | - Steven Okoli
- Imperial College, The Commonwealth Building, The Hammersmith Hospital, Du Cane Rd, London
| | - Raffaele Renella
- Pediatric Hematology-Oncology Research Laboratory, CHUV-UNIL Lausanne Switzerland
| | - Kate Ryan
- Department of Haematology, Manchester Royal Infirmary, Oxford Rd, Manchester
| | - Marjorie Brand
- Sprott Center for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa
| | - Jim Hughes
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Noemi B A Roy
- Department of Haematology, Oxford University Hospitals NHS Trust, Churchill Hospital, Old Rd, Headington, and NIHR Biomedical Research Centre, Oxford
| | - Douglas R Higgs
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Christian Babbs
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford
| | - Veronica J Buckle
- Weatherall Institute of Molecular Medicine, Oxford University, Oxford.
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7
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Coordination of transcription, processing, and export of highly expressed RNAs by distinct biomolecular condensates. Emerg Top Life Sci 2021; 4:281-291. [PMID: 32338276 PMCID: PMC7733674 DOI: 10.1042/etls20190160] [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: 01/02/2020] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 12/30/2022]
Abstract
Genes under control of super-enhancers are expressed at extremely high levels and are frequently associated with nuclear speckles. Recent data suggest that the high concentration of unphosphorylated RNA polymerase II (Pol II) and Mediator recruited to super-enhancers create phase-separated condensates. Transcription initiates within or at the surface of these phase-separated droplets and the phosphorylation of Pol II, associated with transcription initiation and elongation, dissociates Pol II from these domains leading to engagement with nuclear speckles, which are enriched with RNA processing factors. The transitioning of Pol II from transcription initiation domains to RNA processing domains effectively co-ordinates transcription and processing of highly expressed RNAs which are then rapidly exported into the cytoplasm.
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8
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Identification of the transcription factor MAZ as a regulator of erythropoiesis. Blood Adv 2021; 5:3002-3015. [PMID: 34351390 DOI: 10.1182/bloodadvances.2021004609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/11/2021] [Indexed: 12/28/2022] Open
Abstract
Erythropoiesis requires a combination of ubiquitous and tissue-specific transcription factors (TFs). Here, through DNA affinity purification followed by mass spectrometry, we have identified the widely expressed protein MAZ (Myc-associated zinc finger) as a TF that binds to the promoter of the erythroid-specific human α-globin gene. Genome-wide mapping in primary human erythroid cells revealed that MAZ also occupies active promoters as well as GATA1-bound enhancer elements of key erythroid genes. Consistent with an important role during erythropoiesis, knockdown of MAZ reduces α-globin expression in K562 cells and impairs differentiation in primary human erythroid cells. Genetic variants in the MAZ locus are associated with changes in clinically important human erythroid traits. Taken together, these findings reveal the zinc-finger TF MAZ to be a previously unrecognized regulator of the erythroid differentiation program.
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9
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Razin SV, Ioudinkova ES, Kantidze OL, Iarovaia OV. Co-Regulated Genes and Gene Clusters. Genes (Basel) 2021; 12:907. [PMID: 34208174 PMCID: PMC8230824 DOI: 10.3390/genes12060907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 12/27/2022] Open
Abstract
There are many co-regulated genes in eukaryotic cells. The coordinated activation or repression of such genes occurs at specific stages of differentiation, or under the influence of external stimuli. As a rule, co-regulated genes are dispersed in the genome. However, there are also gene clusters, which contain paralogous genes that encode proteins with similar functions. In this aspect, they differ significantly from bacterial operons containing functionally linked genes that are not paralogs. In this review, we discuss the reasons for the existence of gene clusters in vertebrate cells and propose that clustering is necessary to ensure the possibility of selective activation of one of several similar genes.
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Affiliation(s)
- Sergey V. Razin
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia; (E.S.I.); (O.L.K.); (O.V.I.)
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Elena S. Ioudinkova
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia; (E.S.I.); (O.L.K.); (O.V.I.)
| | - Omar L. Kantidze
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia; (E.S.I.); (O.L.K.); (O.V.I.)
| | - Olga V. Iarovaia
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia; (E.S.I.); (O.L.K.); (O.V.I.)
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10
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Sumner MC, Torrisi SB, Brickner DG, Brickner JH. Random sub-diffusion and capture of genes by the nuclear pore reduces dynamics and coordinates inter-chromosomal movement. eLife 2021; 10:66238. [PMID: 34002694 PMCID: PMC8195609 DOI: 10.7554/elife.66238] [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: 01/05/2021] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
Hundreds of genes interact with the yeast nuclear pore complex (NPC), localizing at the nuclear periphery and clustering with co-regulated genes. Dynamic tracking of peripheral genes shows that they cycle on and off the NPC and that interaction with the NPC slows their sub-diffusive movement. Furthermore, NPC-dependent inter-chromosomal clustering leads to coordinated movement of pairs of loci separated by hundreds of nanometers. We developed fractional Brownian motion simulations for chromosomal loci in the nucleoplasm and interacting with NPCs. These simulations predict the rate and nature of random sub-diffusion during repositioning from nucleoplasm to periphery and match measurements from two different experimental models, arguing that recruitment to the nuclear periphery is due to random sub-diffusion and transient capture by NPCs. Finally, the simulations do not lead to inter-chromosomal clustering or coordinated movement, suggesting that interaction with the NPC is necessary, but not sufficient, to cause clustering.
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Affiliation(s)
- Michael Chas Sumner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Steven B Torrisi
- Department of Physics, Harvard University, Cambridge, United States
| | - Donna G Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
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11
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p53 mediates target gene association with nuclear speckles for amplified RNA expression. Mol Cell 2021; 81:1666-1681.e6. [PMID: 33823140 DOI: 10.1016/j.molcel.2021.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/05/2021] [Accepted: 03/03/2021] [Indexed: 01/01/2023]
Abstract
Nuclear speckles are prominent nuclear bodies that contain proteins and RNA involved in gene expression. Although links between nuclear speckles and gene activation are emerging, the mechanisms regulating association of genes with speckles are unclear. We find that speckle association of p53 target genes is driven by the p53 transcription factor. Focusing on p21, a key p53 target, we demonstrate that speckle association boosts expression by elevating nascent RNA amounts. p53-regulated speckle association did not depend on p53 transactivation functions but required an intact proline-rich domain and direct DNA binding, providing mechanisms within p53 for regulating gene-speckle association. Beyond p21, a substantial subset of p53 targets have p53-regulated speckle association. Strikingly, speckle-associating p53 targets are more robustly activated and occupy a distinct niche of p53 biology compared with non-speckle-associating p53 targets. Together, our findings illuminate regulated speckle association as a mechanism used by a transcription factor to boost gene expression.
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12
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Mendieta-Esteban J, Di Stefano M, Castillo D, Farabella I, Marti-Renom MA. 3D reconstruction of genomic regions from sparse interaction data. NAR Genom Bioinform 2021; 3:lqab017. [PMID: 33778492 PMCID: PMC7985034 DOI: 10.1093/nargab/lqab017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/08/2021] [Accepted: 03/02/2021] [Indexed: 01/04/2023] Open
Abstract
Chromosome conformation capture (3C) technologies measure the interaction frequency between pairs of chromatin regions within the nucleus in a cell or a population of cells. Some of these 3C technologies retrieve interactions involving non-contiguous sets of loci, resulting in sparse interaction matrices. One of such 3C technologies is Promoter Capture Hi-C (pcHi-C) that is tailored to probe only interactions involving gene promoters. As such, pcHi-C provides sparse interaction matrices that are suitable to characterize short- and long-range enhancer-promoter interactions. Here, we introduce a new method to reconstruct the chromatin structural (3D) organization from sparse 3C-based datasets such as pcHi-C. Our method allows for data normalization, detection of significant interactions and reconstruction of the full 3D organization of the genomic region despite of the data sparseness. Specifically, it builds, with as low as the 2-3% of the data from the matrix, reliable 3D models of similar accuracy of those based on dense interaction matrices. Furthermore, the method is sensitive enough to detect cell-type-specific 3D organizational features such as the formation of different networks of active gene communities.
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Affiliation(s)
- Julen Mendieta-Esteban
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Marco Di Stefano
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - David Castillo
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Irene Farabella
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Marc A Marti-Renom
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
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13
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Sas-Nowosielska H, Magalska A. Long Noncoding RNAs-Crucial Players Organizing the Landscape of the Neuronal Nucleus. Int J Mol Sci 2021; 22:ijms22073478. [PMID: 33801737 PMCID: PMC8037058 DOI: 10.3390/ijms22073478] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/25/2022] Open
Abstract
The ability to regulate chromatin organization is particularly important in neurons, which dynamically respond to external stimuli. Accumulating evidence shows that lncRNAs play important architectural roles in organizing different nuclear domains like inactive chromosome X, splicing speckles, paraspeckles, and Gomafu nuclear bodies. LncRNAs are abundantly expressed in the nervous system where they may play important roles in compartmentalization of the cell nucleus. In this review we will describe the architectural role of lncRNAs in the nuclei of neuronal cells.
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Gurumurthy A, Yu DT, Stees JR, Chamales P, Gavrilova E, Wassel P, Li L, Stribling D, Chen J, Brackett M, Ishov AM, Xie M, Bungert J. Super-enhancer mediated regulation of adult β-globin gene expression: the role of eRNA and Integrator. Nucleic Acids Res 2021; 49:1383-1396. [PMID: 33476375 PMCID: PMC7897481 DOI: 10.1093/nar/gkab002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 01/05/2023] Open
Abstract
Super-enhancers (SEs) mediate high transcription levels of target genes. Previous studies have shown that SEs recruit transcription complexes and generate enhancer RNAs (eRNAs). We characterized transcription at the human and murine β-globin locus control region (LCR) SE. We found that the human LCR is capable of recruiting transcription complexes independently from linked globin genes in transgenic mice. Furthermore, LCR hypersensitive site 2 (HS2) initiates the formation of bidirectional transcripts in transgenic mice and in the endogenous β-globin gene locus in murine erythroleukemia (MEL) cells. HS2 3′eRNA is relatively unstable and remains in close proximity to the globin gene locus. Reducing the abundance of HS2 3′eRNA leads to a reduction in β-globin gene transcription and compromises RNA polymerase II (Pol II) recruitment at the promoter. The Integrator complex has been shown to terminate eRNA transcription. We demonstrate that Integrator interacts downstream of LCR HS2. Inducible ablation of Integrator function in MEL or differentiating primary human CD34+ cells causes a decrease in expression of the adult β-globin gene and accumulation of Pol II and eRNA at the LCR. The data suggest that transcription complexes are assembled at the LCR and transferred to the globin genes by mechanisms that involve Integrator mediated release of Pol II and eRNA from the LCR.
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Affiliation(s)
- Aishwarya Gurumurthy
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - David T Yu
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Jared R Stees
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Pamela Chamales
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Ekaterina Gavrilova
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Paul Wassel
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Lu Li
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Daniel Stribling
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA.,Department of Molecular Genetics and Microbiology, Gainesville, FL 32610, USA
| | - Jinyang Chen
- Department of Statistics, University of Georgia, Athens, GA 30602, USA
| | - Marissa Brackett
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Alexander M Ishov
- Department of Anatomy and Cell Biology, UF Health Cancer Center, University of Florida, Gainesville, FL, 32610, USA
| | - Mingyi Xie
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
| | - Jörg Bungert
- Department of Biochemistry and Molecular Biology, Center for Epigenetics, Genetics Institute, UF Health Cancer Center, Powell-Gene Therapy Center, Gainesville, FL 32610, USA
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15
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Bertero A. RNA Biogenesis Instructs Functional Inter-Chromosomal Genome Architecture. Front Genet 2021; 12:645863. [PMID: 33732290 PMCID: PMC7957078 DOI: 10.3389/fgene.2021.645863] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Three-dimensional (3D) genome organization has emerged as an important layer of gene regulation in development and disease. The functional properties of chromatin folding within individual chromosomes (i.e., intra-chromosomal or in cis) have been studied extensively. On the other hand, interactions across different chromosomes (i.e., inter-chromosomal or in trans) have received less attention, being often regarded as background noise or technical artifacts. This viewpoint has been challenged by emerging evidence of functional relationships between specific trans chromatin interactions and epigenetic control, transcription, and splicing. Therefore, it is an intriguing possibility that the key processes involved in the biogenesis of RNAs may both shape and be in turn influenced by inter-chromosomal genome architecture. Here I present the rationale behind this hypothesis, and discuss a potential experimental framework aimed at its formal testing. I present a specific example in the cardiac myocyte, a well-studied post-mitotic cell whose development and response to stress are associated with marked rearrangements of chromatin topology both in cis and in trans. I argue that RNA polymerase II clusters (i.e., transcription factories) and foci of the cardiac-specific splicing regulator RBM20 (i.e., splicing factories) exemplify the existence of trans-interacting chromatin domains (TIDs) with important roles in cellular homeostasis. Overall, I propose that inter-molecular 3D proximity between co-regulated nucleic acids may be a pervasive functional mechanism in biology.
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Affiliation(s)
- Alessandro Bertero
- Department of Laboratory Medicine and Pathology, Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, United States
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Bagchi A, Nath A, Thamodaran V, Ijee S, Palani D, Rajendiran V, Venkatesan V, Datari P, Pai AA, Janet NB, Balasubramanian P, Nakamura Y, Srivastava A, Mohankumar KM, Thangavel S, Velayudhan SR. Direct Generation of Immortalized Erythroid Progenitor Cell Lines from Peripheral Blood Mononuclear Cells. Cells 2021; 10:523. [PMID: 33804564 PMCID: PMC7999632 DOI: 10.3390/cells10030523] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 02/04/2023] Open
Abstract
Reliable human erythroid progenitor cell (EPC) lines that can differentiate to the later stages of erythropoiesis are important cellular models for studying molecular mechanisms of human erythropoiesis in normal and pathological conditions. Two immortalized erythroid progenitor cells (iEPCs), HUDEP-2 and BEL-A, generated from CD34+ hematopoietic progenitors by the doxycycline (dox) inducible expression of human papillomavirus E6 and E7 (HEE) genes, are currently being used extensively to study transcriptional regulation of human erythropoiesis and identify novel therapeutic targets for red cell diseases. However, the generation of iEPCs from patients with red cell diseases is challenging as obtaining a sufficient number of CD34+ cells require bone marrow aspiration or their mobilization to peripheral blood using drugs. This study established a protocol for culturing early-stage EPCs from peripheral blood (PB) and their immortalization by expressing HEE genes. We generated two iEPCs, PBiEPC-1 and PBiEPC-2, from the peripheral blood mononuclear cells (PBMNCs) of two healthy donors. These cell lines showed stable doubling times with the properties of erythroid progenitors. PBiEPC-1 showed robust terminal differentiation with high enucleation efficiency, and it could be successfully gene manipulated by gene knockdown and knockout strategies with high efficiencies without affecting its differentiation. This protocol is suitable for generating a bank of iEPCs from patients with rare red cell genetic disorders for studying disease mechanisms and drug discovery.
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Affiliation(s)
- Abhirup Bagchi
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Aneesha Nath
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Vasanth Thamodaran
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Smitha Ijee
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Dhavapriya Palani
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Vignesh Rajendiran
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Vigneshwaran Venkatesan
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
- Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Phaneendra Datari
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
| | - Aswin Anand Pai
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
| | - Nancy Beryl Janet
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
| | - Poonkuzhali Balasubramanian
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
| | - Yukio Nakamura
- Cell Engineering Division, RIKEN BioResource Research Center, Ibaraki 3050074, Japan;
| | - Alok Srivastava
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
| | - Kumarasamypet Murugesan Mohankumar
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Saravanabhavan Thangavel
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
| | - Shaji R. Velayudhan
- Center for Stem Cell Research (A Unit of InStem, Bengaluru, India), Christian Medical College, Vellore 632002, Tamil Nadu, India; (A.B.); (A.N.); (V.T.); (S.I.); (D.P.); (V.R.); (V.V.); (A.S.); (K.M.M.); (S.T.)
- Department of Hematology, Christian Medical College, Vellore 632002, Tamil Nadu, India; (P.D.); (A.A.P.); (N.B.J.); (P.B.)
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Zhang L, Zhang Y, Chen Y, Gholamalamdari O, Wang Y, Ma J, Belmont AS. TSA-seq reveals a largely conserved genome organization relative to nuclear speckles with small position changes tightly correlated with gene expression changes. Genome Res 2021; 31:251-264. [PMID: 33355299 PMCID: PMC7849416 DOI: 10.1101/gr.266239.120] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 12/17/2020] [Indexed: 12/31/2022]
Abstract
TSA-seq mapping suggests that gene distance to nuclear speckles is more deterministic and predictive of gene expression levels than gene radial positioning. Gene expression correlates inversely with distance to nuclear speckles, with chromosome regions of unusually high expression located at the apex of chromosome loops protruding from the nuclear periphery into the interior. Genomic distances to the nearest lamina-associated domain are larger for loop apexes mapping closest to nuclear speckles, suggesting the possibility of conservation of speckle-associated regions. To facilitate comparison of genome organization by TSA-seq, we reduced required cell numbers 10- to 20-fold for TSA-seq by deliberately saturating protein-labeling while preserving distance mapping by the still unsaturated DNA-labeling. Only ∼10% of the genome shows statistically significant shifts in relative nuclear speckle distances in pair-wise comparisons between human cell lines (H1, HFF, HCT116, K562); however, these moderate shifts in nuclear speckle distances tightly correlate with changes in cell type-specific gene expression. Similarly, half of heat shock-induced gene loci already preposition very close to nuclear speckles, with the remaining positioned near or at intermediate distance (HSPH1) to nuclear speckles but shifting even closer with transcriptional induction. Speckle association together with chromatin decondensation correlates with expression amplification upon HSPH1 activation. Our results demonstrate a largely "hardwired" genome organization with specific genes moving small mean distances relative to speckles during cell differentiation or a physiological transition, suggesting an important role of nuclear speckles in gene expression regulation.
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Affiliation(s)
- Liguo Zhang
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Yang Zhang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Yu Chen
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Omid Gholamalamdari
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Yuchuan Wang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Jian Ma
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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18
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Matsui M, Sakasai R, Abe M, Kimura Y, Kajita S, Torii W, Katsuki Y, Ishiai M, Iwabuchi K, Takata M, Nishi R. USP42 enhances homologous recombination repair by promoting R-loop resolution with a DNA-RNA helicase DHX9. Oncogenesis 2020; 9:60. [PMID: 32541651 PMCID: PMC7296013 DOI: 10.1038/s41389-020-00244-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/21/2020] [Accepted: 05/29/2020] [Indexed: 01/05/2023] Open
Abstract
The nucleus of mammalian cells is compartmentalized by nuclear bodies such as nuclear speckles, however, involvement of nuclear bodies, especially nuclear speckles, in DNA repair has not been actively investigated. Here, our focused screen for nuclear speckle factors involved in homologous recombination (HR), which is a faithful DNA double-strand break (DSB) repair mechanism, identified transcription-related nuclear speckle factors as potential HR regulators. Among the top hits, we provide evidence showing that USP42, which is a hitherto unidentified nuclear speckles protein, promotes HR by facilitating BRCA1 recruitment to DSB sites and DNA-end resection. We further showed that USP42 localization to nuclear speckles is required for efficient HR. Furthermore, we established that USP42 interacts with DHX9, which possesses DNA-RNA helicase activity, and is required for efficient resolution of DSB-induced R-loop. In conclusion, our data propose a model in which USP42 facilitates BRCA1 loading to DSB sites, resolution of DSB-induced R-loop and preferential DSB repair by HR, indicating the importance of nuclear speckle-mediated regulation of DSB repair.
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Affiliation(s)
- Misaki Matsui
- Department of Biomedical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Ryo Sakasai
- Department of Biochemistry I, Kanazawa Medical University, Kahoku, Ishikawa, 920-0293, Japan
| | - Masako Abe
- Department of Late Effects Studies, Radiation Biology Centre, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8501, Japan
| | - Yusuke Kimura
- Department of Biomedical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Shoki Kajita
- Department of Biomedical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Wakana Torii
- Department of Biomedical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Yoko Katsuki
- Department of Late Effects Studies, Radiation Biology Centre, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8501, Japan
| | - Masamichi Ishiai
- Central Radioisotope Division, National Cancer Centre Research Institute, Chuoku, Tokyo, 104-0045, Japan
| | - Kuniyoshi Iwabuchi
- Department of Biochemistry I, Kanazawa Medical University, Kahoku, Ishikawa, 920-0293, Japan
| | - Minoru Takata
- Department of Late Effects Studies, Radiation Biology Centre, Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto, 606-8501, Japan
| | - Ryotaro Nishi
- Department of Biomedical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan. .,School of Bioscience and Biotechnology, Tokyo University of Technology, Hachioji, Tokyo, 192-0982, Japan.
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19
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Wang A, Kolhe JA, Gioacchini N, Baade I, Brieher WM, Peterson CL, Freeman BC. Mechanism of Long-Range Chromosome Motion Triggered by Gene Activation. Dev Cell 2020; 52:309-320.e5. [PMID: 31902656 PMCID: PMC7108666 DOI: 10.1016/j.devcel.2019.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 11/18/2019] [Accepted: 12/12/2019] [Indexed: 12/18/2022]
Abstract
Movement of chromosome sites within interphase cells is critical for numerous pathways including RNA transcription and genome organization. Yet, a mechanism for reorganizing chromatin in response to these events had not been reported. Here, we delineate a molecular chaperone-dependent pathway for relocating activated gene loci in yeast. Our presented data support a model in which a two-authentication system mobilizes a gene promoter through a dynamic network of polymeric nuclear actin. Transcription factor-dependent nucleation of a myosin motor propels the gene locus through the actin matrix, and fidelity of the actin association was ensured by ARP-containing chromatin remodelers. Motor activity of nuclear myosin was dependent on the Hsp90 chaperone. Hsp90 further contributed by biasing the remodeler-actin interaction toward nucleosomes with the non-canonical histone H2A.Z, thereby focusing the pathway on select sites such as transcriptionally active genes. Together, the system provides a rapid and effective means to broadly yet selectively mobilize chromatin sites.
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Affiliation(s)
- Anqi Wang
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Janhavi A Kolhe
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Nate Gioacchini
- Program of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Imke Baade
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Craig L Peterson
- Program of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Brian C Freeman
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
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20
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Bera M, Kalyana Sundaram RV. Chromosome Territorial Organization Drives Efficient Protein Complex Formation: A Hypothesis. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:541-548. [PMID: 31543715 PMCID: PMC6747946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In eukaryotes, chromosomes often form a transcriptional kissing loop during interphase. We propose that these kissing loops facilitate the formation of protein complexes. mRNA transcripts from these loops could cluster together into phase-separated nuclear granules. Their export into the ER could be ensured by guided diffusion through the inter-chromatin space followed by association with nuclear baskets and export factors. Inside the ER, these mRNAs would form a translation hub. Juxtaposed translation of these mRNAs would increase the cis/trans protein complex assembly among the nascent protein chains. Eukaryotes might employ this pathway to increase complex formation efficiency.
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Affiliation(s)
- Manindra Bera
- To whom all correspondence should be addressed: Manindra Bera, Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT USA, 06520; Tel: 203-737-3269,
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21
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Bashkirova E, Lomvardas S. Olfactory receptor genes make the case for inter-chromosomal interactions. Curr Opin Genet Dev 2019; 55:106-113. [PMID: 31491591 DOI: 10.1016/j.gde.2019.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/04/2019] [Accepted: 07/07/2019] [Indexed: 12/11/2022]
Abstract
The partitioning of the interphase nucleus into chromosome territories generally precludes DNA from making specific and reproducible inter-chromosomal contacts. However, with the development of powerful genomic and imaging tools for the analysis of the 3D genome, and with their application on an increasing number of cell types, it becomes apparent that regulated, specific, and functionally important inter-chromosomal contacts exist. Widespread and stereotypic inter-chromosomal interactions are at the center of chemosensation, where they regulate the singular and stochastic expression of olfactory receptor genes. In olfactory sensory neurons (OSNs) coalescence of multiple intergenic enhancers to a multi-chromosomal hub orchestrates the expression of a single OR allele, whereas convergence of the remaining OR genes from 18 chromosomes into a few heterochromatic compartments mediates their effective transcriptional silencing. In this review we describe the role of interchromosomal interactions in OR gene choice, and we describe other biological systems where such genomic interactions may contribute to regulatory robustness and transcriptional diversification.
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Affiliation(s)
- Elizaveta Bashkirova
- Department of Biochemistry and Molecular Biophysics, Roy Vangelos Columbia University Medical Center, New York, NY 10032, United States
| | - Stavros Lomvardas
- Department of Biochemistry and Molecular Biophysics, Roy Vangelos Columbia University Medical Center, New York, NY 10032, United States; Department of Neuroscience, Roy Vangelos Columbia University Medical Center, Columbia University, New York, NY 10032, United States; Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10027, United States; Kavli Institute for Neurosciences at Columbia University, New York, NY 10027, United States.
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22
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Chen Y, Belmont AS. Genome organization around nuclear speckles. Curr Opin Genet Dev 2019; 55:91-99. [PMID: 31394307 DOI: 10.1016/j.gde.2019.06.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 01/08/2023]
Abstract
Higher eukaryotic cell nuclei are highly compartmentalized into bodies and structural assemblies of specialized functions. Nuclear speckles/IGCs are one of the most prominent nuclear bodies, yet their functional significance remains largely unknown. Recent advances in sequence-based mapping of nuclear genome organization now provide genome-wide analysis of chromosome organization relative to nuclear speckles. Here we review older microscopy-based studies on a small number of genes with the new genomic mapping data suggesting a significant fraction of the genome is almost deterministically positioned near nuclear speckles. Both microscopy and genomic-based approaches support the concept of the nuclear speckle periphery as a major active chromosomal compartment which may play an important role in fine-tuning gene regulation.
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Affiliation(s)
- Yu Chen
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, Berkeley, CA 94720, USA
| | - Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, B107 CLSL, 601 S. Goodwin Avenue, Urbana, IL 61801, USA.
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23
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Pellestor F. Chromoanagenesis: cataclysms behind complex chromosomal rearrangements. Mol Cytogenet 2019; 12:6. [PMID: 30805029 PMCID: PMC6371609 DOI: 10.1186/s13039-019-0415-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 01/17/2019] [Indexed: 12/21/2022] Open
Abstract
Background During the last decade, genome sequencing projects in cancer genomes as well as in patients with congenital diseases and healthy individuals have led to the identification of new types of massive chromosomal rearrangements arising during single chaotic cellular events. These unanticipated catastrophic phenomenon are termed chromothripsis, chromoanasynthesis and chromoplexis., and are grouped under the name of “chromoanagenesis”. Results For each process, several specific features have been described, allowing each phenomenon to be distinguished from each other and to understand its mechanism of formation and to better understand its aetiology. Thus, chromothripsis derives from chromosome shattering followed by the random restitching of chromosomal fragments with low copy-number change whereas chromoanasynthesis results from erroneous DNA replication of a chromosome through serial fork stalling and template switching with variable copy-number gains, and chromoplexy refers to the occurrence of multiple inter-and intra-chromosomal translocations and deletions with little or no copy-number alterations in prostate cancer. Cumulating data and experimental models have shown that chromothripsis and chromoanasynthesis may essentially result from lagging chromosome encapsulated in micronuclei or telomere attrition and end-to-end telomere fusion. Conclusion The concept of chromanagenesis has provided new insight into the aetiology of complex structural rearrangements, the connection between defective cell cycle progression and genomic instability, and the complexity of cancer evolution. Increasing reported chromoanagenesis events suggest that these chaotic mechanisms are probably much more frequent than anticipated.
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Affiliation(s)
- Franck Pellestor
- Unit of Chromosomal Genetics, Department of Medical Genetics, Arnaud de Villeneuve Hospital, Montpellier CHRU, 371, avenue du Doyen Gaston Giraud, 34295 Montpellier cedex 5, France.,INSERM 1183 Unit «Genome and Stem Cell Plasticity in Development and Aging », Institute of Regenerative Medicine and Biotherapies, St Eloi Hospital, Montpellier, France
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24
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Pollex T, Heard E. Nuclear positioning and pairing of X-chromosome inactivation centers are not primary determinants during initiation of random X-inactivation. Nat Genet 2019; 51:285-295. [PMID: 30643252 DOI: 10.1038/s41588-018-0305-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 11/02/2018] [Indexed: 01/29/2023]
Abstract
During X-chromosome inactivation (XCI), one of the two X-inactivation centers (Xics) upregulates the noncoding RNA Xist to initiate chromosomal silencing in cis. How one Xic is chosen to upregulate Xist remains unclear. Models proposed include localization of one Xic at the nuclear envelope or transient homologous Xic pairing followed by asymmetric transcription factor distribution at Xist's antisense Xite/Tsix locus. Here, we use a TetO/TetR system that can inducibly relocate one or both Xics to the nuclear lamina in differentiating mouse embryonic stem cells. We find that neither nuclear lamina localization nor reduction of Xic homologous pairing influences monoallelic Xist upregulation or choice-making. We also show that transient pairing is associated with biallelic expression, not only at Xist/Tsix but also at other X-linked loci that can escape XCI. Finally, we show that Xic pairing occurs in wavelike patterns, coinciding with genome dynamics and the onset of global regulatory programs during early differentiation.
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Affiliation(s)
- Tim Pollex
- Mammalian Developmental Epigenetics Group, Genetics and Developmental Biology Unit, Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.,European Molecular Biology Laboratory, Heidelberg, Germany
| | - Edith Heard
- Mammalian Developmental Epigenetics Group, Genetics and Developmental Biology Unit, Institut Curie, PSL Research University, CNRS UMR3215, INSERM U934, Paris, France.
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25
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Brown JM, Roberts NA, Graham B, Waithe D, Lagerholm C, Telenius JM, De Ornellas S, Oudelaar AM, Scott C, Szczerbal I, Babbs C, Kassouf MT, Hughes JR, Higgs DR, Buckle VJ. A tissue-specific self-interacting chromatin domain forms independently of enhancer-promoter interactions. Nat Commun 2018; 9:3849. [PMID: 30242161 PMCID: PMC6155075 DOI: 10.1038/s41467-018-06248-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 08/24/2018] [Indexed: 11/08/2022] Open
Abstract
Self-interacting chromatin domains encompass genes and their cis-regulatory elements; however, the three-dimensional form a domain takes, whether this relies on enhancer-promoter interactions, and the processes necessary to mediate the formation and maintenance of such domains, remain unclear. To examine these questions, here we use a combination of high-resolution chromosome conformation capture, a non-denaturing form of fluorescence in situ hybridisation and super-resolution imaging to study a 70 kb domain encompassing the mouse α-globin regulatory locus. We show that this region forms an erythroid-specific, decompacted, self-interacting domain, delimited by frequently apposed CTCF/cohesin binding sites early in terminal erythroid differentiation, and does not require transcriptional elongation for maintenance of the domain structure. Formation of this domain does not rely on interactions between the α-globin genes and their major enhancers, suggesting a transcription-independent mechanism for establishment of the domain. However, absence of the major enhancers does alter internal domain interactions. Formation of a loop domain therefore appears to be a mechanistic process that occurs irrespective of the specific interactions within.
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Affiliation(s)
- Jill M Brown
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Nigel A Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Bryony Graham
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Dominic Waithe
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Christoffer Lagerholm
- Wolfson Imaging Centre Oxford, MRC Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK
| | - Jelena M Telenius
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Sara De Ornellas
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - A Marieke Oudelaar
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Caroline Scott
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Izabela Szczerbal
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637 Poznan, Poland
| | - Christian Babbs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Mira T Kassouf
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Douglas R Higgs
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK
| | - Veronica J Buckle
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Oxford University, Oxford, OX3 9DS, UK.
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26
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Heat Shock Protein Genes Undergo Dynamic Alteration in Their Three-Dimensional Structure and Genome Organization in Response to Thermal Stress. Mol Cell Biol 2017; 37:MCB.00292-17. [PMID: 28970326 DOI: 10.1128/mcb.00292-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/15/2017] [Indexed: 01/11/2023] Open
Abstract
Three-dimensional (3D) chromatin organization is important for proper gene regulation, yet how the genome is remodeled in response to stress is largely unknown. Here, we use a highly sensitive version of chromosome conformation capture in combination with fluorescence microscopy to investigate Heat Shock Protein (HSP) gene conformation and 3D nuclear organization in budding yeast. In response to acute thermal stress, HSP genes undergo intense intragenic folding interactions that go well beyond 5'-3' gene looping previously described for RNA polymerase II genes. These interactions include looping between upstream activation sequence (UAS) and promoter elements, promoter and terminator regions, and regulatory and coding regions (gene "crumpling"). They are also dynamic, being prominent within 60 s, peaking within 2.5 min, and attenuating within 30 min, and correlate with HSP gene transcriptional activity. With similarly striking kinetics, activated HSP genes, both chromosomally linked and unlinked, coalesce into discrete intranuclear foci. Constitutively transcribed genes also loop and crumple yet fail to coalesce. Notably, a missense mutation in transcription factor TFIIB suppresses gene looping, yet neither crumpling nor HSP gene coalescence is affected. An inactivating promoter mutation, in contrast, obviates all three. Our results provide evidence for widespread, transcription-associated gene crumpling and demonstrate the de novo assembly and disassembly of HSP gene foci.
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27
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Galganski L, Urbanek MO, Krzyzosiak WJ. Nuclear speckles: molecular organization, biological function and role in disease. Nucleic Acids Res 2017; 45:10350-10368. [PMID: 28977640 PMCID: PMC5737799 DOI: 10.1093/nar/gkx759] [Citation(s) in RCA: 285] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/18/2017] [Indexed: 12/13/2022] Open
Abstract
The nucleoplasm is not homogenous; it consists of many types of nuclear bodies, also known as nuclear domains or nuclear subcompartments. These self-organizing structures gather machinery involved in various nuclear activities. Nuclear speckles (NSs) or splicing speckles, also called interchromatin granule clusters, were discovered as sites for splicing factor storage and modification. Further studies on transcription and mRNA maturation and export revealed a more general role for splicing speckles in RNA metabolism. Here, we discuss the functional implications of the localization of numerous proteins crucial for epigenetic regulation, chromatin organization, DNA repair and RNA modification to nuclear speckles. We highlight recent advances suggesting that NSs facilitate integrated regulation of gene expression. In addition, we consider the influence of abundant regulatory and signaling proteins, i.e. protein kinases and proteins involved in protein ubiquitination, phosphoinositide signaling and nucleoskeletal organization, on pre-mRNA synthesis and maturation. While many of these regulatory proteins act within NSs, direct evidence for mRNA metabolism events occurring in NSs is still lacking. NSs contribute to numerous human diseases, including cancers and viral infections. In addition, recent data have demonstrated close relationships between these structures and the development of neurological disorders.
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Affiliation(s)
- Lukasz Galganski
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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28
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Brickner J. Genetic and epigenetic control of the spatial organization of the genome. Mol Biol Cell 2017; 28:364-369. [PMID: 28137949 PMCID: PMC5341720 DOI: 10.1091/mbc.e16-03-0149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 11/11/2022] Open
Abstract
Eukaryotic genomes are spatially organized within the nucleus by chromosome folding, interchromosomal contacts, and interaction with nuclear structures. This spatial organization is observed in diverse organisms and both reflects and contributes to gene expression and differentiation. This leads to the notion that the arrangement of the genome within the nucleus has been shaped and conserved through evolutionary processes and likely plays an adaptive function. Both DNA-binding proteins and changes in chromatin structure influence the positioning of genes and larger domains within the nucleus. This suggests that the spatial organization of the genome can be genetically encoded by binding sites for DNA-binding proteins and can also involve changes in chromatin structure, potentially through nongenetic mechanisms. Here I briefly discuss the results that support these ideas and their implications for how genomes encode spatial organization.
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Affiliation(s)
- Jason Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
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29
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How does chromatin package DNA within nucleus and regulate gene expression? Int J Biol Macromol 2017; 101:862-881. [PMID: 28366861 DOI: 10.1016/j.ijbiomac.2017.03.165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/26/2023]
Abstract
The human body is made up of 60 trillion cells, each cell containing 2 millions of genomic DNA in its nucleus. How is this genomic deoxyribonucleic acid [DNA] organised into nuclei? Around 1880, W. Flemming discovered a nuclear substance that was clearly visible on staining under primitive light microscopes and named it 'chromatin'; this is now thought to be the basic unit of genomic DNA organization. Since long before DNA was known to carry genetic information, chromatin has fascinated biologists. DNA has a negatively charged phosphate backbone that produces electrostatic repulsion between adjacent DNA regions, making it difficult for DNA to fold upon itself. In this article, we will try to shed light on how does chromatin package DNA within nucleus and regulate gene expression?
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30
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Brickner DG, Sood V, Tutucci E, Coukos R, Viets K, Singer RH, Brickner JH. Subnuclear positioning and interchromosomal clustering of the GAL1-10 locus are controlled by separable, interdependent mechanisms. Mol Biol Cell 2016; 27:2980-93. [PMID: 27489341 PMCID: PMC5042583 DOI: 10.1091/mbc.e16-03-0174] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/27/2016] [Indexed: 01/10/2023] Open
Abstract
“DNA zip codes” control positioning and interchromosomal clustering of GAL1-10 in yeast. However, these two phenomena have distinct molecular mechanisms, requiring different nuclear pore proteins, and are regulated differently by transcription and the cell cycle. On activation, the GAL genes in yeast are targeted to the nuclear periphery through interaction with the nuclear pore complex. Here we identify two cis-acting “DNA zip codes” from the GAL1-10 promoter that are necessary and sufficient to induce repositioning to the nuclear periphery. One of these zip codes, GRS4, is also necessary and sufficient to promote clustering of GAL1-10 alleles. GRS4, and to a lesser extent GRS5, contribute to stronger expression of GAL1 and GAL10 by increasing the fraction of cells that respond to the inducer. The molecular mechanism controlling targeting to the NPC is distinct from the molecular mechanism controlling interchromosomal clustering. Targeting to the nuclear periphery and interaction with the nuclear pore complex are prerequisites for gene clustering. However, once formed, clustering can be maintained in the nucleoplasm, requires distinct nuclear pore proteins, and is regulated differently through the cell cycle. In addition, whereas targeting of genes to the NPC is independent of transcription, interchromosomal clustering requires transcription. These results argue that zip code–dependent gene positioning at the nuclear periphery and interchromosomal clustering represent interdependent phenomena with distinct molecular mechanisms.
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Affiliation(s)
| | - Varun Sood
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Evelina Tutucci
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Robert Coukos
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Kayla Viets
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461 Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
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31
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Meaburn KJ. Spatial Genome Organization and Its Emerging Role as a Potential Diagnosis Tool. Front Genet 2016; 7:134. [PMID: 27507988 PMCID: PMC4961005 DOI: 10.3389/fgene.2016.00134] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/13/2016] [Indexed: 12/12/2022] Open
Abstract
In eukaryotic cells the genome is highly spatially organized. Functional relevance of higher order genome organization is implied by the fact that specific genes, and even whole chromosomes, alter spatial position in concert with functional changes within the nucleus, for example with modifications to chromatin or transcription. The exact molecular pathways that regulate spatial genome organization and the full implication to the cell of such an organization remain to be determined. However, there is a growing realization that the spatial organization of the genome can be used as a marker of disease. While global genome organization patterns remain largely conserved in disease, some genes and chromosomes occupy distinct nuclear positions in diseased cells compared to their normal counterparts, with the patterns of reorganization differing between diseases. Importantly, mapping the spatial positioning patterns of specific genomic loci can distinguish cancerous tissue from benign with high accuracy. Genome positioning is an attractive novel biomarker since additional quantitative biomarkers are urgently required in many cancer types. Current diagnostic techniques are often subjective and generally lack the ability to identify aggressive cancer from indolent, which can lead to over- or under-treatment of patients. Proof-of-principle for the use of genome positioning as a diagnostic tool has been provided based on small scale retrospective studies. Future large-scale studies are required to assess the feasibility of bringing spatial genome organization-based diagnostics to the clinical setting and to determine if the positioning patterns of specific loci can be useful biomarkers for cancer prognosis. Since spatial reorganization of the genome has been identified in multiple human diseases, it is likely that spatial genome positioning patterns as a diagnostic biomarker may be applied to many diseases.
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Affiliation(s)
- Karen J. Meaburn
- Cell Biology of Genomes Group, National Cancer Institute, National Institutes of HealthBethesda, MD, USA
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32
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Randise-Hinchliff C, Brickner JH. Transcription factors dynamically control the spatial organization of the yeast genome. Nucleus 2016; 7:369-74. [PMID: 27442220 PMCID: PMC5039007 DOI: 10.1080/19491034.2016.1212797] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
In yeast, inducible genes such as INO1, PRM1 and HIS4 reposition from the nucleoplasm to nuclear periphery upon activation. This leads to a physical interaction with nuclear pore complex (NPC), interchromosomal clustering, and stronger transcription. Repositioning to the nuclear periphery is controlled by cis-acting transcription factor (TF) binding sites located within the promoters of these genes and the TFs that bind to them. Such elements are both necessary and sufficient to control positioning of genes to the nuclear periphery. We have identified 4 TFs capable of controlling the regulated positioning of genes to the nuclear periphery in budding yeast under different conditions: Put3, Cbf1, Gcn4 and Ste12. In each case, we have defined the molecular basis of regulated relocalization to the nuclear periphery. Put3- and Cbf1-mediated targeting to nuclear periphery is regulated through local recruitment of Rpd3(L) histone deacetylase complex by transcriptional repressors. Rpd3(L), through its histone deacetylase activity, prevents TF-mediated gene positioning by blocking TF binding. Many yeast transcriptional repressors were capable of blocking Put3-mediated recruitment; 11 of these required Rpd3. Thus, it is a general function of transcription repressors to regulate TF-mediated recruitment. However, Ste12 and Gcn4-mediated recruitment is regulated independently of Rpd3(L) and transcriptional repressors. Ste12-mediated recruitment is regulated by phosphorylation of an inhibitor called Dig2, and Gcn4-mediated gene targeting is up-regulated by increasing Gcn4 protein levels. The ability to control spatial position of genes in yeast represents a novel function for TFs and different regulatory strategies provide dynamic control of the yeast genome through different time scales.
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Affiliation(s)
| | - Jason H Brickner
- a Department of Molecular Biosciences , Northwestern University , Evanston , IL , USA
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33
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Ding N, Xi J, Li Y, Xie X, Shi J, Zhang Z, Li Y, Fang F, Wang S, Yue W, Pei X, Fang X. Global transcriptome analysis for identification of interactions between coding and noncoding RNAs during human erythroid differentiation. Front Med 2016; 10:297-310. [PMID: 27272188 DOI: 10.1007/s11684-016-0452-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/22/2016] [Indexed: 12/26/2022]
Abstract
Studies on coding genes, miRNAs, and lncRNAs during erythroid development have been performed in recent years. However, analysis focusing on the integration of the three RNA types has yet to be done. In the present study, we compared the dynamics of coding genes, miRNA, and lncRNA expression profiles. To explore dynamic changes in erythropoiesis and potential mechanisms that control these changes in the transcriptome level, we took advantage of high throughput sequencing technologies to obtain transcriptome data from cord blood hematopoietic stem cells and the following four erythroid differentiation stages, as well as from mature red blood cells. Results indicated that lncRNAs were promising cell marker candidates for erythroid differentiation. Clustering analysis classified the differentially expressed genes into four subtypes that corresponded to dynamic changes during stemness maintenance, mid-differentiation, and maturation. Integrated analysis revealed that noncoding RNAs potentially participated in controlling blood cell maturation, and especially associated with heme metabolism and responses to oxygen species and DNA damage. These regulatory interactions were displayed in a comprehensive network, thereby inferring correlations between RNAs and their associated functions. These data provided a substantial resource for the study of normal erythropoiesis, which will permit further investigation and understanding of erythroid development and acquired erythroid disorders.
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Affiliation(s)
- Nan Ding
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiafei Xi
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Yanming Li
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaoyan Xie
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Jian Shi
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhaojun Zhang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanhua Li
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Fang Fang
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Sihan Wang
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Wen Yue
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China.,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China
| | - Xuetao Pei
- Lab of Stem Cell and Regenerative Medicine, Beijing Institute of Transfusion Medicine, AMMS, Beijing, 100850, China. .,South China Research Center for Stem Cell & Regenerative Medicine, AMMS, Guangzhou, 510300, China.
| | - Xiangdong Fang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
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34
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Vaquerizas JM, Akhtar A, Luscombe NM. Large-scale nuclear architecture and transcriptional control. Subcell Biochem 2016; 52:279-95. [PMID: 21557088 DOI: 10.1007/978-90-481-9069-0_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Transcriptional regulation is one the most basic mechanisms for controlling gene expression. Over the past few years, much research has been devoted to understanding the interplay between transcription factors, histone modifications and associated enzymes required to achieve this control. However, it is becoming increasingly apparent that the three-dimensional conformation of chromatin in the interphase nucleus also plays a critical role in regulating transcription. Chromatin localisation in the nucleus is highly organised, and early studies described strong interactions between chromatin and sub-nuclear components. Single-gene studies have shed light on how chromosomal architecture affects gene expression. Lately, this has been complemented by whole-genome studies that have determined the global chromatin conformation of living cells in interphase. These studies have greatly expanded our understanding of nuclear architecture and its interplay with different physiological processes. Despite these advances, however, most of the mechanisms used to impose the three-dimensional chromatin structure remain unknown. Here, we summarise the different levels of chromatin organisation in the nucleus and discuss current efforts into characterising the mechanisms that govern it.
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35
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Randise-Hinchliff C, Coukos R, Sood V, Sumner MC, Zdraljevic S, Meldi Sholl L, Garvey Brickner D, Ahmed S, Watchmaker L, Brickner JH. Strategies to regulate transcription factor-mediated gene positioning and interchromosomal clustering at the nuclear periphery. J Cell Biol 2016; 212:633-46. [PMID: 26953353 PMCID: PMC4792077 DOI: 10.1083/jcb.201508068] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/02/2016] [Indexed: 11/23/2022] Open
Abstract
In yeast, transcription factors mediate gene positioning at the nuclear periphery and interchromosomal clustering. These phenomena are regulated by several different strategies that lead to dynamic changes in the spatial arrangement of genes over different time scales. In budding yeast, targeting of active genes to the nuclear pore complex (NPC) and interchromosomal clustering is mediated by transcription factor (TF) binding sites in the gene promoters. For example, the binding sites for the TFs Put3, Ste12, and Gcn4 are necessary and sufficient to promote positioning at the nuclear periphery and interchromosomal clustering. However, in all three cases, gene positioning and interchromosomal clustering are regulated. Under uninducing conditions, local recruitment of the Rpd3(L) histone deacetylase by transcriptional repressors blocks Put3 DNA binding. This is a general function of yeast repressors: 16 of 21 repressors blocked Put3-mediated subnuclear positioning; 11 of these required Rpd3. In contrast, Ste12-mediated gene positioning is regulated independently of DNA binding by mitogen-activated protein kinase phosphorylation of the Dig2 inhibitor, and Gcn4-dependent targeting is up-regulated by increasing Gcn4 protein levels. These different regulatory strategies provide either qualitative switch-like control or quantitative control of gene positioning over different time scales.
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Affiliation(s)
| | - Robert Coukos
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Varun Sood
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Michael Chas Sumner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Stefan Zdraljevic
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Lauren Meldi Sholl
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | | | - Sara Ahmed
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Lauren Watchmaker
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
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36
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Affiliation(s)
- Huy Q. Nguyen
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755;
| | - Giovanni Bosco
- Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire 03755;
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37
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Brickner DG, Coukos R, Brickner JH. INO1 transcriptional memory leads to DNA zip code-dependent interchromosomal clustering. MICROBIAL CELL 2015; 2:481-490. [PMID: 26688804 PMCID: PMC4682904 DOI: 10.15698/mic2015.12.242] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Many genes localize at the nuclear periphery through physical interaction with the nuclear pore complex (NPC). We have found that the yeast INO1 gene is targeted to the NPC both upon activation and for several generations after repression, a phenomenon called epigenetic transcriptional memory. Targeting of INO1 to the NPC requires distinct cis-acting promoter DNA zip codes under activating conditions and under memory conditions. When at the nuclear periphery, active INO1 clusters with itself and with other genes that share the GRS I zip code. Here, we show that during memory, the two alleles of INO1 cluster in diploids and endogenous INO1 clusters with an ectopic INO1 in haploids. After repression, INO1 does not cluster with GRS I - containing genes. Furthermore, clustering during memory requires Nup100 and two sets of DNA zip codes, those that target INO1 to the periphery when active and those that target it to the periphery after repression. Therefore, the interchromosomal clustering of INO1 that occurs during transcriptional memory is dependent upon, but mechanistically distinct from, the clustering of active INO1. Finally, while localization to the nuclear periphery is not regulated through the cell cycle during memory, clustering of INO1 during memory is regulated through the cell cycle.
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Affiliation(s)
- Donna Garvey Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL USA 60201
| | - Robert Coukos
- Department of Molecular Biosciences, Northwestern University, Evanston, IL USA 60201
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL USA 60201
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38
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Abstract
To accommodate genomes in the limited space of the cell nucleus and ensure the correct execution of gene expression programs, genomes are packaged in complex fashion in the three-dimensional cell nucleus. As a consequence of the extensive higher-order organization of chromosomes, distantly located genomic regions on the same or distinct chromosomes undergo long-range interactions. This article discusses the nature of long interactions, mechanisms of their formation, and their emerging functional roles in gene regulation and genome maintenance.
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Affiliation(s)
- Job Dekker
- University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
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39
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Fraser J, Williamson I, Bickmore WA, Dostie J. An Overview of Genome Organization and How We Got There: from FISH to Hi-C. Microbiol Mol Biol Rev 2015; 79:347-72. [PMID: 26223848 PMCID: PMC4517094 DOI: 10.1128/mmbr.00006-15] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In humans, nearly two meters of genomic material must be folded to fit inside each micrometer-scale cell nucleus while remaining accessible for gene transcription, DNA replication, and DNA repair. This fact highlights the need for mechanisms governing genome organization during any activity and to maintain the physical organization of chromosomes at all times. Insight into the functions and three-dimensional structures of genomes comes mostly from the application of visual techniques such as fluorescence in situ hybridization (FISH) and molecular approaches including chromosome conformation capture (3C) technologies. Recent developments in both types of approaches now offer the possibility of exploring the folded state of an entire genome and maybe even the identification of how complex molecular machines govern its shape. In this review, we present key methodologies used to study genome organization and discuss what they reveal about chromosome conformation as it relates to transcription regulation across genomic scales in mammals.
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Affiliation(s)
- James Fraser
- Department of Biochemistry, and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
| | - Iain Williamson
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Josée Dostie
- Department of Biochemistry, and Goodman Cancer Research Center, McGill University, Montréal, Québec, Canada
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40
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Khan WA, Rogan PK, Knoll JHM. Reversing chromatin accessibility differences that distinguish homologous mitotic metaphase chromosomes. Mol Cytogenet 2015; 8:65. [PMID: 26273322 PMCID: PMC4535684 DOI: 10.1186/s13039-015-0159-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/09/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chromatin-modifying reagents that alter histone associating proteins, DNA conformation or its sequence are well established strategies for studying chromatin structure in interphase (G1, S, G2). Little is known about how these compounds act during metaphase. We assessed the effects of these reagents at genomic loci that show reproducible, non-random differences in accessibility to chromatin that distinguish homologous targets by single copy DNA probe fluorescence in situ hybridization (scFISH). By super-resolution 3-D structured illumination microscopy (3D-SIM) and other criteria, the differences correspond to 'differential accessibility' (DA) to these chromosomal regions. At these chromosomal loci, DA of the same homologous chromosome is stable and epigenetic hallmarks of less accessible interphase chromatin are present. RESULTS To understand the basis for DA, we investigate the impact of epigenetic modifiers on these allelic differences in chromatin accessibility between metaphase homologs in lymphoblastoid cell lines. Allelic differences in metaphase chromosome accessibility represent a stable chromatin mark on mitotic metaphase chromosomes. Inhibition of the topoisomerase IIα-DNA cleavage complex reversed DA. Inter-homolog probe fluorescence intensity ratios between chromosomes treated with ICRF-193 were significantly lower than untreated controls. 3D-SIM demonstrated that differences in hybridized probe volume and depth between allelic targets were equalized by this treatment. By contrast, DA was impervious to chromosome decondensation treatments targeting histone modifying enzymes, cytosine methylation, as well as in cells with regulatory defects in chromatid cohesion. These data altogether suggest that DA is a reflection of allelic differences in metaphase chromosome compaction, dictated by the localized catenation state of the chromosome, rather than by other epigenetic marks. CONCLUSIONS Inhibition of the topoisomerase IIα-DNA cleavage complex mitigated DA by decreasing DNA superhelicity and axial metaphase chromosome condensation. This has potential implications for the mechanism of preservation of cellular phenotypes that enables the same chromatin structure to be correctly reestablished in progeny cells of the same tissue or individual.
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Affiliation(s)
- Wahab A. Khan
- />Department of Pathology and Laboratory Medicine, University of Western Ontario, London, N6A 5C1 ON Canada
| | - Peter K. Rogan
- />Departments of Biochemistry, Computer Science, and Oncology, University of Western Ontario, London, N6A 5C1 ON Canada
- />Cytognomix, Inc., London, N6G 4X8 ON Canada
| | - Joan H. M. Knoll
- />Department of Pathology and Laboratory Medicine, University of Western Ontario, London, N6A 5C1 ON Canada
- />Cytognomix, Inc., London, N6G 4X8 ON Canada
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41
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Silva AM, Brown JM, Buckle VJ, Wade-Martins R, Lufino MMP. Expanded GAA repeats impair FXN gene expression and reposition the FXN locus to the nuclear lamina in single cells. Hum Mol Genet 2015; 24:3457-71. [PMID: 25814655 PMCID: PMC4498154 DOI: 10.1093/hmg/ddv096] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/12/2015] [Indexed: 02/07/2023] Open
Abstract
Abnormally expanded DNA repeats are associated with several neurodegenerative diseases. In Friedreich's ataxia (FRDA), expanded GAA repeats in intron 1 of the frataxin gene (FXN) reduce FXN mRNA levels in averaged cell samples through a poorly understood mechanism. By visualizing FXN expression and nuclear localization in single cells, we show that GAA-expanded repeats decrease the number of FXN mRNA molecules, slow transcription, and increase FXN localization at the nuclear lamina (NL). Restoring histone acetylation reverses NL positioning. Expanded GAA-FXN loci in FRDA patient cells show increased NL localization with increased silencing of alleles and reduced transcription from alleles positioned peripherally. We also demonstrate inefficiencies in transcription initiation and elongation from the expanded GAA-FXN locus at single-cell resolution. We suggest that repressive epigenetic modifications at the expanded GAA-FXN locus may lead to NL relocation, where further repression may occur.
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Affiliation(s)
- Ana M Silva
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal and
| | - Jill M Brown
- Medical Research Council, Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Veronica J Buckle
- Medical Research Council, Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK,
| | - Michele M P Lufino
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK,
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42
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Schubert V, Weisshart K. Abundance and distribution of RNA polymerase II in Arabidopsis interphase nuclei. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1687-98. [PMID: 25740920 PMCID: PMC4357323 DOI: 10.1093/jxb/erv091] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
RNA polymerase II (RNAPII) is responsible for the transcription of most eukaryotic protein-coding genes. Analysing the topological distribution and quantification of RNAPII can contribute to understanding its function in interphase nuclei. Previously it was shown that RNAPII molecules in plant nuclei form reticulate structures within euchromatin of differentiated Arabidopsis thaliana nuclei rather than being organized in distinct 'transcription factories' as observed in mammalian nuclei. Immunosignal intensity measurements based on specific antibody labelling in maximum intensity projections of image stacks acquired by structured illumination microscopy (SIM) suggested a relative proportional increase of RNAPII in endopolyploid plant nuclei. Here, photoactivated localization microscopy (PALM) was applied to determine the absolute number and distribution of active and inactive RNAPII molecules in differentiated A. thaliana nuclei. The proportional increase of RNAPII during endopolyploidization is confirmed, but it is also shown that PALM measurements are more reliable than those based on SIM in terms of quantification. The single molecule localization results show that, although RNAPII molecules are globally dispersed within plant euchromatin, they also aggregate within smaller distances as described for mammalian transcription factories.
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Affiliation(s)
- Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466 Stadt Seeland, Germany
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43
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Chakraborty S, Mehta I, Kulashreshtha M, Rao BJ. Quantitative analysis of chromosome localization in the nucleus. Methods Mol Biol 2015; 1228:223-33. [PMID: 25311133 DOI: 10.1007/978-1-4939-1680-1_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The spatial organization of the genome within the interphase nucleus is important for mediating genome functions. The radial organization of chromosome territories has been studied traditionally using two-dimensional fluorescence in situ hybridization (FISH) using labeled whole chromosome probes. Information from 2D-FISH images is analyzed quantitatively and is depicted in the form of the spatial distribution of chromosomes territories. However, to the best of our knowledge no open-access tools are available to delineate the position of chromosome territories from 2D-FISH images. In this chapter we present a methodology termed Image Analysis of Chromosomes for computing their localization (IMACULAT). IMACULAT is an open-access, automated tool that partitions the cell nucleus into shells of equal area or volume and computes the spatial distribution of chromosome territories.
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Affiliation(s)
- Sandeep Chakraborty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India,
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44
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O'Sullivan JM, Doynova MD, Antony J, Pichlmuller F, Horsfield JA. Insights from space: potential role of diet in the spatial organization of chromosomes. Nutrients 2014; 6:5724-39. [PMID: 25514390 PMCID: PMC4276994 DOI: 10.3390/nu6125724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/20/2014] [Accepted: 11/21/2014] [Indexed: 02/07/2023] Open
Abstract
We can now sequence and identify genome wide epigenetic patterns and perform a variety of "genomic experiments" within relatively short periods of time-ranging from days to weeks. Yet, despite these technological advances, we have a poor understanding of the inter-relationships between epigenetics, genome structure-function, and nutrition. Perhaps this limitation lies, in part, in our propensity to study epigenetics in terms of the linear arrangement of elements and genes. Here we propose that a more complete understanding of how nutrition impacts on epigenetics and cellular development resides within the inter-relationships between DNA and histone modification patterns and genome function, in the context of spatial organization of chromatin and the epigenome.
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Affiliation(s)
- Justin M O'Sullivan
- The Liggins Institute, The University of Auckland, Private Bag 92019 AMC, Auckland 1142, New Zealand.
| | - Malina D Doynova
- The Liggins Institute, The University of Auckland, Private Bag 92019 AMC, Auckland 1142, New Zealand.
| | - Jisha Antony
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin 9054, New Zealand.
| | - Florian Pichlmuller
- The Liggins Institute, The University of Auckland, Private Bag 92019 AMC, Auckland 1142, New Zealand.
| | - Julia A Horsfield
- Department of Pathology, Dunedin School of Medicine, The University of Otago, P.O. Box 913, Dunedin 9054, New Zealand.
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45
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Schubert V, Rudnik R, Schubert I. Chromatin associations in Arabidopsis interphase nuclei. Front Genet 2014; 5:389. [PMID: 25431580 PMCID: PMC4230181 DOI: 10.3389/fgene.2014.00389] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 10/23/2014] [Indexed: 11/30/2022] Open
Abstract
The arrangement of chromatin within interphase nuclei seems to be caused by topological constraints and related to gene expression depending on tissue and developmental stage. In yeast and animals it was found that homologous and heterologous chromatin association are required to realize faithful expression and DNA repair. To test whether such associations are present in plants we analyzed Arabidopsis thaliana interphase nuclei by FISH using probes from different chromosomes. We found that chromatin fiber movement and variable associations, although in general relatively seldom, may occur between euchromatin segments along chromosomes, sometimes even over large distances. The combination of euchromatin segments bearing high or low co-expressing genes did not reveal different association frequencies probably due to adjacent genes of deviating expression patterns. Based on previous data and on FISH analyses presented here, we conclude that the global interphase chromatin organization in A. thaliana is relatively stable, due to the location of its 10 centromeres at the nuclear periphery and of the telomeres mainly at the centrally localized nucleolus. Nevertheless, chromatin movement enables a flexible spatial genome arrangement in plant nuclei.
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Affiliation(s)
- Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany
| | - Radoslaw Rudnik
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany
| | - Ingo Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben Stadt Seeland, Germany ; Faculty of Science and Central European Institute of Technology, Masaryk University Brno, Czech Republic
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46
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Dnmt1-independent CG methylation contributes to nucleosome positioning in diverse eukaryotes. Cell 2014; 156:1286-1297. [PMID: 24630728 DOI: 10.1016/j.cell.2014.01.029] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 10/25/2013] [Accepted: 01/10/2014] [Indexed: 11/24/2022]
Abstract
Dnmt1 epigenetically propagates symmetrical CG methylation in many eukaryotes. Their genomes are typically depleted of CG dinucleotides because of imperfect repair of deaminated methylcytosines. Here, we extensively survey diverse species lacking Dnmt1 and show that, surprisingly, symmetrical CG methylation is nonetheless frequently present and catalyzed by a different DNA methyltransferase family, Dnmt5. Numerous Dnmt5-containing organisms that diverged more than a billion years ago exhibit clustered methylation, specifically in nucleosome linkers. Clustered methylation occurs at unprecedented densities and directly disfavors nucleosomes, contributing to nucleosome positioning between clusters. Dense methylation is enabled by a regime of genomic sequence evolution that enriches CG dinucleotides and drives the highest CG frequencies known. Species with linker methylation have small, transcriptionally active nuclei that approach the physical limits of chromatin compaction. These features constitute a previously unappreciated genome architecture, in which dense methylation influences nucleosome positions, likely facilitating nuclear processes under extreme spatial constraints.
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47
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Wood AM, Garza-Gongora AG, Kosak ST. A Crowdsourced nucleus: understanding nuclear organization in terms of dynamically networked protein function. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1839:178-90. [PMID: 24412853 PMCID: PMC3954575 DOI: 10.1016/j.bbagrm.2014.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 01/14/2023]
Abstract
The spatial organization of the nucleus results in a compartmentalized structure that affects all aspects of nuclear function. This compartmentalization involves genome organization as well as the formation of nuclear bodies and plays a role in many functions, including gene regulation, genome stability, replication, and RNA processing. Here we review the recent findings associated with the spatial organization of the nucleus and reveal that a common theme for nuclear proteins is their ability to participate in a variety of functions and pathways. We consider this multiplicity of function in terms of Crowdsourcing, a recent phenomenon in the world of information technology, and suggest that this model provides a novel way to synthesize the many intersections between nuclear organization and function. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.
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Affiliation(s)
- Ashley M Wood
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Arturo G Garza-Gongora
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Steven T Kosak
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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48
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Mehta IS, Kulashreshtha M, Chakraborty S, Kolthur-Seetharam U, Rao BJ. Chromosome territories reposition during DNA damage-repair response. Genome Biol 2013; 14:R135. [PMID: 24330859 PMCID: PMC4062845 DOI: 10.1186/gb-2013-14-12-r135] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 12/13/2013] [Indexed: 01/02/2023] Open
Abstract
Background Local higher-order chromatin structure, dynamics and composition of the DNA are known to determine double-strand break frequencies and the efficiency of repair. However, how DNA damage response affects the spatial organization of chromosome territories is still unexplored. Results Our report investigates the effect of DNA damage on the spatial organization of chromosome territories within interphase nuclei of human cells. We show that DNA damage induces a large-scale spatial repositioning of chromosome territories that are relatively gene dense. This response is dose dependent, and involves territories moving from the nuclear interior to the periphery and vice versa. Furthermore, we have found that chromosome territory repositioning is contingent upon double-strand break recognition and damage sensing. Importantly, our results suggest that this is a reversible process where, following repair, chromosome territories re-occupy positions similar to those in undamaged control cells. Conclusions Thus, our report for the first time highlights DNA damage-dependent spatial reorganization of whole chromosomes, which might be an integral aspect of cellular damage response.
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49
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Rieder D, Ploner C, Krogsdam AM, Stocker G, Fischer M, Scheideler M, Dani C, Amri EZ, Müller WG, McNally JG, Trajanoski Z. Co-expressed genes prepositioned in spatial neighborhoods stochastically associate with SC35 speckles and RNA polymerase II factories. Cell Mol Life Sci 2013; 71:1741-59. [PMID: 24026398 DOI: 10.1007/s00018-013-1465-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 08/02/2013] [Accepted: 08/28/2013] [Indexed: 11/26/2022]
Abstract
Chromosomally separated, co-expressed genes can be in spatial proximity, but there is still debate about how this nuclear organization is achieved. Proposed mechanisms include global genome organization, preferential positioning of chromosome territories, or gene-gene sharing of various nuclear bodies. To investigate this question, we selected a set of genes that were co-expressed upon differentiation of human multipotent stem cells. We applied a novel multi-dimensional analysis procedure which revealed that prior to gene expression, the relative position of these genes was conserved in nuclei. Upon stem cell differentiation and concomitant gene expression, we found that co-expressed genes were closer together. In addition, we found that genes in the same 1-μm-diameter neighborhood associated with either the same splicing speckle or to a lesser extent with the same transcription factory. Dispersal of speckles by overexpression of the serine-arginine (SR) protein kinase cdc2-like kinase Clk2 led to a significant drop in the number of genes in shared neighborhoods. We demonstrate quantitatively that the frequencies of speckle and factory sharing can be explained by assuming stochastic selection of a nuclear body within a restricted sub-volume defined by the original global gene positioning present prior to gene expression. We conclude that the spatial organization of these genes is a two-step process in which transcription-induced association with nuclear bodies enhances and refines a pre-existing global organization.
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Affiliation(s)
- Dietmar Rieder
- Division of Bioinformatics, Biocenter, Innsbruck Medical University, Innrain 80, 6020, Innsbruck, Austria
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50
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Abstract
In vivo, the human genome functions as a complex, folded, three-dimensional chromatin polymer. Understanding how the human genome is spatially organized and folded inside the cell nucleus is therefore central to understanding how genes are regulated in normal development and dysregulated in disease. Established light microscopy-based approaches and more recent molecular chromosome conformation capture methods are now combining to give us unprecedented insight into this fascinating aspect of human genomics.
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Affiliation(s)
- Wendy A Bickmore
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom;
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