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Pabba MK, Ritter C, Chagin VO, Meyer J, Celikay K, Stear JH, Loerke D, Kolobynina K, Prorok P, Schmid AK, Leonhardt H, Rohr K, Cardoso MC. Replisome loading reduces chromatin motion independent of DNA synthesis. eLife 2023; 12:RP87572. [PMID: 37906089 PMCID: PMC10617993 DOI: 10.7554/elife.87572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023] Open
Abstract
Chromatin has been shown to undergo diffusional motion, which is affected during gene transcription by RNA polymerase activity. However, the relationship between chromatin mobility and other genomic processes remains unclear. Hence, we set out to label the DNA directly in a sequence unbiased manner and followed labeled chromatin dynamics in interphase human cells expressing GFP-tagged proliferating cell nuclear antigen (PCNA), a cell cycle marker and core component of the DNA replication machinery. We detected decreased chromatin mobility during the S-phase compared to G1 and G2 phases in tumor as well as normal diploid cells using automated particle tracking. To gain insight into the dynamical organization of the genome during DNA replication, we determined labeled chromatin domain sizes and analyzed their motion in replicating cells. By correlating chromatin mobility proximal to the active sites of DNA synthesis, we showed that chromatin motion was locally constrained at the sites of DNA replication. Furthermore, inhibiting DNA synthesis led to increased loading of DNA polymerases. This was accompanied by accumulation of the single-stranded DNA binding protein on the chromatin and activation of DNA helicases further restricting local chromatin motion. We, therefore, propose that it is the loading of replisomes but not their catalytic activity that reduces the dynamics of replicating chromatin segments in the S-phase as well as their accessibility and probability of interactions with other genomic regions.
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Affiliation(s)
| | - Christian Ritter
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Vadim O Chagin
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
- Institute of Cytology RASSt. PetersburgRussian Federation
| | - Janis Meyer
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Kerem Celikay
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - Jeffrey H Stear
- EMBL Australia Node in Single Molecule Science, University of New South WalesSydneyAustralia
| | - Dinah Loerke
- Department of Physics & Astronomy, University of DenverDenverUnited States
| | - Ksenia Kolobynina
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
| | - Paulina Prorok
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
| | - Alice Kristin Schmid
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | | | - Karl Rohr
- Biomedical Computer Vision Group, BioQuant, IPMB, Heidelberg UniversityHeidelbergGermany
| | - M Cristina Cardoso
- Department of Biology, Technical University of DarmstadtDarmstadtGermany
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2
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de Lima MF, Lisboa MDO, Terceiro LEL, Rangel-Pozzo A, Mai S. Chromosome Territories in Hematological Malignancies. Cells 2022; 11:cells11081368. [PMID: 35456046 PMCID: PMC9028803 DOI: 10.3390/cells11081368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/12/2022] [Accepted: 04/15/2022] [Indexed: 11/21/2022] Open
Abstract
Chromosomes are organized in distinct nuclear areas designated as chromosome territories (CT). The structural formation of CT is a consequence of chromatin packaging and organization that ultimately affects cell function. Chromosome positioning can identify structural signatures of genomic organization, especially for diseases where changes in gene expression contribute to a given phenotype. The study of CT in hematological diseases revealed chromosome position as an important factor for specific chromosome translocations. In this review, we highlight the history of CT theory, current knowledge on possible clinical applications of CT analysis, and the impact of CT in the development of hematological neoplasia such as multiple myeloma, leukemia, and lymphomas. Accumulating data on nuclear architecture in cancer allow one to propose the three-dimensional nuclear genomic landscape as a novel cancer biomarker for the future.
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Affiliation(s)
- Matheus Fabiao de Lima
- Department of Physiology and Pathophysiology, CancerCare Manitoba Research Institute, University of Manitoba, Winnipeg, MB R3E 0V9, Canada;
| | - Mateus de Oliveira Lisboa
- Core for Cell Technology, School of Medicine, Pontifícia Universidade Católica do Paraná—PUCPR, Curitiba 80215-901, Brazil;
| | - Lucas E. L. Terceiro
- Department of Pathology, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB R3E 3P5, Canada;
| | - Aline Rangel-Pozzo
- Department of Physiology and Pathophysiology, CancerCare Manitoba Research Institute, University of Manitoba, Winnipeg, MB R3E 0V9, Canada;
- Correspondence: (A.R.-P.); (S.M.); Tel.: +1-204-787-2135 (S.M.)
| | - Sabine Mai
- Department of Physiology and Pathophysiology, CancerCare Manitoba Research Institute, University of Manitoba, Winnipeg, MB R3E 0V9, Canada;
- Correspondence: (A.R.-P.); (S.M.); Tel.: +1-204-787-2135 (S.M.)
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3
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García Fernández F, Fabre E. The Dynamic Behavior of Chromatin in Response to DNA Double-Strand Breaks. Genes (Basel) 2022; 13:genes13020215. [PMID: 35205260 PMCID: PMC8872016 DOI: 10.3390/genes13020215] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
The primary functions of the eukaryotic nucleus as a site for the storage, retrieval, and replication of information require a highly dynamic chromatin organization, which can be affected by the presence of DNA damage. In response to double-strand breaks (DSBs), the mobility of chromatin at the break site is severely affected and, to a lesser extent, that of other chromosomes. The how and why of such movement has been widely studied over the last two decades, leading to different mechanistic models and proposed potential roles underlying both local and global mobility. Here, we review the state of the knowledge on current issues affecting chromatin mobility upon DSBs, and highlight its role as a crucial step in the DNA damage response (DDR).
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Affiliation(s)
- Fabiola García Fernández
- Institut Curie, CNRS UMR3664, Sorbonne Université, F-75005 Paris, France
- Correspondence: (F.G.F.); (E.F.)
| | - Emmanuelle Fabre
- Génomes Biologie Cellulaire et Thérapeutiques, CNRS UMR7212, INSERM U944, Université de Paris, F-75010 Paris, France
- Correspondence: (F.G.F.); (E.F.)
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4
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Levchenko SM, Pliss A, Peng X, Prasad PN, Qu J. Fluorescence lifetime imaging for studying DNA compaction and gene activities. LIGHT, SCIENCE & APPLICATIONS 2021; 10:224. [PMID: 34728612 PMCID: PMC8563720 DOI: 10.1038/s41377-021-00664-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 10/04/2021] [Accepted: 10/18/2021] [Indexed: 05/04/2023]
Abstract
Optical imaging is a most useful and widespread technique for the investigation of the structure and function of the cellular genomes. However, an analysis of immensely convoluted and irregularly compacted DNA polymer is highly challenging even by modern super-resolution microscopy approaches. Here we propose fluorescence lifetime imaging (FLIM) for the advancement of studies of genomic structure including DNA compaction, replication as well as monitoring of gene expression. The proposed FLIM assay employs two independent mechanisms for DNA compaction sensing. One mechanism relies on the inverse quadratic relation between the fluorescence lifetimes of fluorescence probes incorporated into DNA and their local refractive index, variable due to DNA compaction density. Another mechanism is based on the Förster resonance energy transfer (FRET) process between the donor and the acceptor fluorophores, both incorporated into DNA. Both these proposed mechanisms were validated in cultured cells. The obtained data unravel a significant difference in compaction of the gene-rich and gene-poor pools of genomic DNA. We show that the gene-rich DNA is loosely compacted compared to the dense DNA domains devoid of active genes.
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Affiliation(s)
- Svitlana M Levchenko
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
- Department of Cell Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland
| | - Artem Pliss
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, 14260-3000, USA
| | - Xiao Peng
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China
| | - Paras N Prasad
- Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, 14260-3000, USA.
| | - Junle Qu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China.
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5
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Shukron O, Seeber A, Amitai A, Holcman D. Advances Using Single-Particle Trajectories to Reconstruct Chromatin Organization and Dynamics. Trends Genet 2019; 35:685-705. [PMID: 31371030 DOI: 10.1016/j.tig.2019.06.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 06/12/2019] [Accepted: 06/26/2019] [Indexed: 12/16/2022]
Abstract
Chromatin organization remains complex and far from understood. In this article, we review recent statistical methods of extracting biophysical parameters from in vivo single-particle trajectories of loci to reconstruct chromatin reorganization in response to cellular stress such as DNA damage. We look at methods for analyzing both single locus and multiple loci tracked simultaneously and explain how to quantify and describe chromatin motion using a combination of extractable parameters. These parameters can be converted into information about chromatin dynamics and function. Furthermore, we discuss how the timescale of recurrent encounter between loci can be extracted and interpreted. We also discuss the effect of sampling rate on the estimated parameters. Finally, we review a polymer method to reconstruct chromatin structure using crosslinkers between chromatin sites. We list and refer to some software packages that are now publicly available to simulate polymer motion. To conclude, chromatin organization and dynamics can be reconstructed from locus trajectories and predicted based on polymer models.
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Affiliation(s)
- O Shukron
- Group of Data Modeling, Computational Biology and Predictive Medicine, Institut de Biologie, CNRS/INSERM/PSL Ecole Normale Supérieure, Paris, 75005, France
| | - A Seeber
- Center for Advanced Imaging, Northwest Building, 52 Oxford St, Suite 147, Harvard University, Cambridge, MA, 02138, USA
| | - A Amitai
- Department of Chemical Engineering, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; The Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA
| | - D Holcman
- Group of Data Modeling, Computational Biology and Predictive Medicine, Institut de Biologie, CNRS/INSERM/PSL Ecole Normale Supérieure, Paris, 75005, France.
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6
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Fritz AJ, Sehgal N, Pliss A, Xu J, Berezney R. Chromosome territories and the global regulation of the genome. Genes Chromosomes Cancer 2019; 58:407-426. [PMID: 30664301 DOI: 10.1002/gcc.22732] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 12/29/2022] Open
Abstract
Spatial positioning is a fundamental principle governing nuclear processes. Chromatin is organized as a hierarchy from nucleosomes to Mbp chromatin domains (CD) or topologically associating domains (TADs) to higher level compartments culminating in chromosome territories (CT). Microscopic and sequencing techniques have substantiated chromatin organization as a critical factor regulating gene expression. For example, enhancers loop back to interact with their target genes almost exclusively within TADs, distally located coregulated genes reposition into common transcription factories upon activation, and Mbp CDs exhibit dynamic motion and configurational changes in vivo. A longstanding question in the nucleus field is whether an interactive nuclear matrix provides a direct link between structure and function. The findings of nonrandom radial positioning of CT within the nucleus suggest the possibility of preferential interaction patterns among populations of CT. Sequential labeling up to 10 CT followed by application of computer imaging and geometric graph mining algorithms revealed cell-type specific interchromosomal networks (ICN) of CT that are altered during the cell cycle, differentiation, and cancer progression. It is proposed that the ICN correlate with the global level of genome regulation. These approaches also demonstrated that the large scale 3-D topology of CT is specific for each CT. The cell-type specific proximity of certain chromosomal regions in normal cells may explain the propensity of distinct translocations in cancer subtypes. Understanding how genes are dysregulated upon disruption of the normal "wiring" of the nucleus by translocations, deletions, and amplifications that are hallmarks of cancer, should enable more targeted therapeutic strategies.
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Affiliation(s)
- Andrew J Fritz
- Department of Biochemistry and University of Vermont Cancer Center, The University of Vermont Larner College of Medicine, Burlington, Vermont
| | - Nitasha Sehgal
- Department of Biological Sciences, University at Buffalo, Buffalo, New York
| | - Artem Pliss
- Institute for Lasers, Photonics and Biophotonics and the Department of Chemistry, University at Buffalo, Buffalo, New York
| | - Jinhui Xu
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, New York
| | - Ronald Berezney
- Department of Biological Sciences, University at Buffalo, Buffalo, New York
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7
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Abstract
Recent advances in both the technologies used to measure chromatin movement and the biophysical analysis used to model them have yielded a fuller understanding of chromatin dynamics and the polymer structure that underlies it. Changes in nucleosome packing, checkpoint kinase activation, the cell cycle, chromosomal tethers, and external forces acting on nuclei in response to external and internal stimuli can alter the basal mobility of DNA in interphase nuclei of yeast or mammalian cells. Although chromatin movement is assumed to be necessary for many DNA-based processes, including gene activation by distal enhancer–promoter interaction or sequence-based homology searches during double-strand break repair, experimental evidence supporting an essential role in these activities is sparse. Nonetheless, high-resolution tracking of chromatin dynamics has led to instructive models of the higher-order folding and flexibility of the chromatin polymer. Key regulators of chromatin motion in physiological conditions or after damage induction are reviewed here.
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Affiliation(s)
- Andrew Seeber
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
- Current affiliation: Harvard Center for Advanced Imaging, Cambridge, MA 02138, USA
| | - Michael H. Hauer
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
| | - Susan M. Gasser
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Faculty of Natural Sciences, University of Basel, 4056 Basel, Switzerland
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8
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Arifulin EA, Musinova YR, Vassetzky YS, Sheval EV. Mobility of Nuclear Components and Genome Functioning. BIOCHEMISTRY (MOSCOW) 2018; 83:690-700. [PMID: 30195325 DOI: 10.1134/s0006297918060068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell nucleus is characterized by strong compartmentalization of structural components in its three-dimensional space. Certain genomic functions are accompanied by changes in the localization of chromatin loci and nuclear bodies. Here we review recent data on the mobility of nuclear components and the role of this mobility in genome functioning.
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Affiliation(s)
- E A Arifulin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
| | - Y R Musinova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Y S Vassetzky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.,UMR8126, CNRS, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, 94805, France
| | - E V Sheval
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, Villejuif, 94805, France
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9
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Gothe HJ, Minneker V, Roukos V. Dynamics of Double-Strand Breaks: Implications for the Formation of Chromosome Translocations. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1044:27-38. [PMID: 29956289 DOI: 10.1007/978-981-13-0593-1_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Illegitimate joining of chromosome breaks can lead to the formation of chromosome translocations, a catastrophic type of genome rearrangements that often plays key roles in tumorigenesis. Emerging evidence suggests that the mobility of broken DNA loci can be an important determinant in partner search and clustering of individual breaks, events that can influence translocation frequency. We summarize here the recent literature on the mechanisms that regulate chromatin movement, focusing on studies exploring the motion properties of double-strand breaks in the context of chromatin, the functional consequences for DNA repair, and the formation of chromosome fusions.
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10
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Abstract
Chromosome translocations are catastrophic genomic events and often play key roles in tumorigenesis. Yet the biogenesis of chromosome translocations is remarkably poorly understood. Recent work has delineated several distinct mechanistic steps in the formation of translocations, and it has become apparent that non-random spatial genome organization, DNA repair pathways and chromatin features, including histone marks and the dynamic motion of broken chromatin, are critical for determining translocation frequency and partner selection.
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Affiliation(s)
| | - Tom Misteli
- National Cancer Institute, Bethesda, Maryland 20892, USA
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11
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Wójcik K, Zarębski M, Cossarizza A, Dobrucki JW. Daunomycin, an antitumor DNA intercalator, influences histone-DNA interactions. Cancer Biol Ther 2013; 14:823-32. [PMID: 23792590 DOI: 10.4161/cbt.25328] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Although daunomycin and adriamycin are considered effective antitumor drugs and have been used in the clinic for over 40 years, their mechanism of action is still a matter of debate. We investigated the influence of daunomycin on interaction between linker or core histones and DNA in live HeLa cells in vitro, using image and flow cytometry. Exposure to daunomycin at clinically relevant concentrations (25-250 nM) caused dissociation of wild-type H1.1 as well as 4 H1 point mutants from DNA, followed by their accumulation in nucleoli and aggregation of chromatin. A detectable dissociation of H2B core histones occurred only at much higher concentrations of the drug (500 nM). Replication of DNA and synthesis of RNA were not halted by daunomycin (up to 2500 nM); however the characteristic subnuclear distribution of sites of transcription and replication was lost. Dissociation of the H1.1 linker histones and subsequent loss of higher order chromatin structures may constitute an important component of the mechanism of cytotoxicity of daunomycin.
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Affiliation(s)
- Krzysztof Wójcik
- Division of Cell Biophysics; Faculty of Biochemistry, Biophysics and Biotechnology; Jagiellonian University; Kraków, Poland
| | - Mirosław Zarębski
- Division of Cell Biophysics; Faculty of Biochemistry, Biophysics and Biotechnology; Jagiellonian University; Kraków, Poland
| | - Andrea Cossarizza
- University of Modena and Reggio Emilia; School of Medicine; Department of Biomedical Sciences; Modena, Italy
| | - Jurek W Dobrucki
- Division of Cell Biophysics; Faculty of Biochemistry, Biophysics and Biotechnology; Jagiellonian University; Kraków, Poland
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12
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Dion V, Gasser SM. Chromatin movement in the maintenance of genome stability. Cell 2013; 152:1355-64. [PMID: 23498942 DOI: 10.1016/j.cell.2013.02.010] [Citation(s) in RCA: 164] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 11/24/2022]
Abstract
Mechanistic analyses based on improved imaging techniques have begun to explore the biological implications of chromatin movement within the nucleus. Studies in both prokaryotes and eukaryotes have shed light on what regulates the mobility of DNA over long distances. Interestingly, in eukaryotes, genomic loci increase their movement in response to double-strand break induction. Break mobility, in turn, correlates with the efficiency of repair by homologous recombination. We review here the source and regulation of DNA mobility and discuss how it can both contribute to and jeopardize genome stability.
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Affiliation(s)
- Vincent Dion
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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13
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Pliss A, Malyavantham KS, Bhattacharya S, Berezney R. Chromatin dynamics in living cells: Identification of oscillatory motion. J Cell Physiol 2012; 228:609-16. [DOI: 10.1002/jcp.24169] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 07/31/2012] [Indexed: 01/13/2023]
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14
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Pliss A, Zhao L, Ohulchanskyy TY, Qu J, Prasad PN. Fluorescence lifetime of fluorescent proteins as an intracellular environment probe sensing the cell cycle progression. ACS Chem Biol 2012; 7:1385-92. [PMID: 22594453 DOI: 10.1021/cb300065w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The fluorescence lifetime of fluorescent proteins is affected by the concentration of solutes in a medium, in inverse correlation with local refractive index. In this paper, we introduce the concept of using this dependence to probe cellular molecular environment and its transformation during cellular processes. We employ the fluorescence lifetime of Green Fluorescent Protein and tdTomato Fluorescent Protein expressed in cultured cells and probe the changes in the local molecular environment during the cell cycle progression. We report that the longest fluorescence lifetimes occurred during mitosis. Following the cell division, the fluorescence lifetimes of these proteins were rapidly shortened. Furthermore the fluorescence lifetime of tdTomato in the nucleoplasm gradually increased throughout the span of S-phase and remained constantly long until the end of interphase. We interpret the observed fluorescence lifetime changes to be derived from changes in concentration of macromolecular solutes in the cell interior throughout cell cycle progression.
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Affiliation(s)
- Artem Pliss
- Institute for Lasers, Photonics
and Biophotonics, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
| | - Lingling Zhao
- Institute for Lasers, Photonics
and Biophotonics, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
| | - Tymish Y. Ohulchanskyy
- Institute for Lasers, Photonics
and Biophotonics, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
| | - Junle Qu
- Key Laboratory of Optoelectronic
Devices and Systems of Ministry of Education and Guangdong Province,
Institute of Optoelectronics, Shenzhen University, 3688 Nanhai Road, Shenzhen, Guangdong Province 518060, PR China
| | - Paras N. Prasad
- Institute for Lasers, Photonics
and Biophotonics, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States
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15
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Krawczyk PM, Borovski T, Stap J, Cijsouw T, ten Cate R, Medema JP, Kanaar R, Franken NAP, Aten JA. Chromatin mobility is increased at sites of DNA double-strand breaks. J Cell Sci 2012; 125:2127-33. [PMID: 22328517 DOI: 10.1242/jcs.089847] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
DNA double-strand breaks (DSBs) can efficiently kill cancer cells, but they can also produce unwanted chromosome rearrangements when DNA ends from different DSBs are erroneously joined. Movement of DSB-containing chromatin domains might facilitate these DSB interactions and promote the formation of chromosome rearrangements. Therefore, we analyzed the mobility of chromatin domains containing DSBs, marked by the fluorescently tagged DSB marker 53BP1, in living mammalian cells and compared it with the mobility of undamaged chromatin on a time-scale relevant for DSB repair. We found that chromatin domains containing DSBs are substantially more mobile than intact chromatin, and are capable of roaming a more than twofold larger area of the cell nucleus. Moreover, this increased DSB mobility, but not the mobility of undamaged chromatin, can be reduced by agents that affect higher-order chromatin organization.
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Affiliation(s)
- P M Krawczyk
- van Leeuwenhoek Centre for Advanced Microscopy-AMC, Department of Cell Biology & Histology, University of Amsterdam, Amsterdam, The Netherlands.
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16
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Innate structure of DNA foci restricts the mixing of DNA from different chromosome territories. PLoS One 2011; 6:e27527. [PMID: 22205925 PMCID: PMC3244381 DOI: 10.1371/journal.pone.0027527] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 10/19/2011] [Indexed: 01/15/2023] Open
Abstract
The distribution of chromatin within the mammalian nucleus is constrained by its organization into chromosome territories (CTs). However, recent studies have suggested that promiscuous intra- and inter-chromosomal interactions play fundamental roles in regulating chromatin function and so might define the spatial integrity of CTs. In order to test the extent of DNA mixing between CTs, DNA foci of individual CTs were labeled in living cells following incorporation of Alexa-488 and Cy-3 conjugated replication precursor analogues during consecutive cell cycles. Uniquely labeled chromatin domains, resolved following random mitotic segregation, were visualized as discrete structures with defined borders. At the level of resolution analysed, evidence for mixing of chromatin from adjacent domains was only apparent within the surface volumes where neighboring CTs touched. However, while less than 1% of the nuclear volume represented domains of inter-chromosomal mixing, the dynamic plasticity of DNA foci within individual CTs allows continual transformation of CT structure so that different domains of chromatin mixing evolve over time. Notably, chromatin mixing at the boundaries of adjacent CTs had little impact on the innate structural properties of DNA foci. However, when TSA was used to alter the extent of histone acetylation changes in chromatin correlated with increased chromatin mixing. We propose that DNA foci maintain a structural integrity that restricts widespread mixing of DNA and discuss how the potential to dynamically remodel genome organization might alter during cell differentiation.
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17
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Spatial epigenetics: linking nuclear structure and function in higher eukaryotes. Essays Biochem 2010; 48:25-43. [DOI: 10.1042/bse0480025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Eukaryotic cells are defined by the genetic information that is stored in their DNA. To function, this genetic information must be decoded. In doing this, the information encoded in DNA is copied first into RNA, during RNA transcription. Primary RNA transcripts are generated within transcription factories, where they are also processed into mature mRNAs, which then pass to the cytoplasm. In the cytoplasm these mRNAs can finally be translated into protein in order to express the genetic information as a functional product. With only rare exceptions, the cells of an individual multicellular eukaryote contain identical genetic information. However, as different genes must be expressed in different cell types to define the structure and function of individual tissues, it is clear that mechanisms must have evolved to regulate gene expression. In higher eukaryotes, mechanisms that regulate the interaction of DNA with the sites where nuclear functions are performed provide one such layer of regulation. In this chapter, I evaluate how a detailed understanding of nuclear structure and chromatin dynamics are beginning to reveal how spatial mechanisms link chromatin structure and function. As these mechanisms operate to modulate the genetic information in DNA, the regulation of chromatin function by nuclear architecture defines the concept of ‘spatial epigenetics’.
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18
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