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Laghmach R, Di Pierro M, Potoyan DA. Four-Dimensional Mesoscale Liquid Model of Nucleus Resolves Chromatin's Radial Organization. PRX LIFE 2024; 2:013006. [PMID: 38601142 PMCID: PMC11005002 DOI: 10.1103/prxlife.2.013006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Recent advances chromatin capture, imaging techniques, and polymer modeling have dramatically enhanced quantitative understanding of chromosomal folding. However, the dynamism inherent in genome architectures due to physical and biochemical forces and their impact on nuclear architecture and cellular functions remains elusive. While imaging of chromatin in four dimensions is becoming more common, there is a conspicuous lack of physics-based computational tools appropriate for revealing the forces that shape nuclear architecture and dynamics. To this end, we have developed a multiphase liquid model of the nucleus, which can resolve chromosomal territories, compartments, and nuclear lamina using a physics-based and data-informed free-energy function. The model enables rapid hypothesis-driven prototyping of nuclear dynamics in four dimensions, thereby facilitating comparison with whole nucleus imaging experiments. As an application, we model the Drosophila nucleus and map phase diagram of various possible nuclear morphologies. We shed light on the interplay of adhesive and cohesive interactions which give rise to distinct radial organization seen in conventional, inverted, and senescent nuclear architectures. The results also show the highly dynamic nature of the radial organization, the disruption of which leads to significant variability in domain coarsening dynamics and consequently variability of chromatin architecture. The model also highlights the impact of oblate nuclear geometry and heterochromatin-subtype interactions on the global chromatin architecture and local asymmetry of chromatin compartments.
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Affiliation(s)
- Rabia Laghmach
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Michele Di Pierro
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Davit A. Potoyan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA and Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA
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Salafranca J, Ko JK, Mukherjee AK, Fritzsche M, van Grinsven E, Udalova IA. Neutrophil nucleus: shaping the past and the future. J Leukoc Biol 2023; 114:585-594. [PMID: 37480361 PMCID: PMC10673716 DOI: 10.1093/jleuko/qiad084] [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] [Received: 03/21/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023] Open
Abstract
Neutrophils are innate immune cells that are key to protecting the host against infection and maintaining body homeostasis. However, if dysregulated, they can contribute to disease, such as in cancer or chronic autoinflammatory disorders. Recent studies have highlighted the heterogeneity in the neutrophil compartment and identified the presence of immature neutrophils and their precursors in these pathologies. Therefore, understanding neutrophil maturity and the mechanisms through which they contribute to disease is critical. Neutrophils were first characterized morphologically by Ehrlich in 1879 using microscopy, and since then, different technologies have been used to assess neutrophil maturity. The advances in the imaging field, including state-of-the-art microscopy and machine learning algorithms for image analysis, reinforce the use of neutrophil nuclear morphology as a fundamental marker of maturity, applicable for objective classification in clinical diagnostics. New emerging approaches, such as the capture of changes in chromatin topology, will provide mechanistic links between the nuclear shape, chromatin organization, and transcriptional regulation during neutrophil maturation.
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Affiliation(s)
- Julia Salafranca
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Jacky Ka Ko
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Ananda K Mukherjee
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Marco Fritzsche
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Erinke van Grinsven
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
| | - Irina A Udalova
- The Kennedy Institute of Rheumatology, University of Oxford, Old Road Campus Research Build, Roosevelt Dr, Headington, Oxford OX3 7DQ, United Kingdom
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Chung YC, Bisht M, Thuma J, Tu LC. Single-chromosome dynamics reveals locus-dependent dynamics and chromosome territory orientation. J Cell Sci 2023; 136:289470. [PMID: 36718642 PMCID: PMC10022681 DOI: 10.1242/jcs.260137] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
Dynamic chromatin organization instantly influences DNA accessibility through modulating local macromolecular density and interactions, driving changes in transcription activities. Chromatin dynamics have been reported to be locally confined but contribute to coherent chromatin motion across the entire nucleus. However, the regulation of dynamics, nuclear orientation and compaction of subregions along a single chromosome are not well-understood. We used CRISPR-based real-time single-particle tracking and polymer models to characterize the dynamics of specific genomic loci and determine compaction levels of large human chromosomal domains. Our studies showed that chromosome compaction changed during interphase and that compactions of two arms on chromosome 19 were different. The dynamics of genomic loci were subdiffusive and dependent on chromosome regions and transcription states. Surprisingly, the correlation between locus-dependent nuclear localization and mobility was negligible. Strong tethering interactions detected at the pericentromeric region implies local condensation or associations with organelles within local nuclear microenvironments, such as chromatin-nuclear body association. Based on our findings, we propose a 'guided radial model' for the nuclear orientation of the long arm of chromosome 19.
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Affiliation(s)
- Yu-Chieh Chung
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Madhoolika Bisht
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Jenna Thuma
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Li-Chun Tu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA
- Author for correspondence ()
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Makai D, Cseh A, Sepsi A, Makai S. A Multigraph-Based Representation of Hi-C Data. Genes (Basel) 2022; 13:genes13122189. [PMID: 36553456 PMCID: PMC9778156 DOI: 10.3390/genes13122189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/10/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
Chromatin-chromatin interactions and three-dimensional (3D) spatial structures are involved in transcriptional regulation and have a decisive role in DNA replication and repair. To understand how individual genes and their regulatory elements function within the larger genomic context, and how the genome reacts to environmental stimuli, the linear sequence information needs to be interpreted in three-dimensional space, which is still a challenging task. Here, we propose a novel, heuristic approach to represent Hi-C datasets by a whole-genomic pseudo-structure in 3D space. The baseline of our approach is the construction of a multigraph from genomic-sequence data and Hi-C interaction data, then applying a modified force-directed layout algorithm. The resulting layout is a pseudo-structure. While pseudo-structures are not based on direct observation and their details are inherent to settings, surprisingly, they demonstrate interesting, overall similarities of known genome structures of both barley and rice, namely, the Rabl and Rosette-like conformation. It has an exciting potential to be extended by additional omics data (RNA-seq, Chip-seq, etc.), allowing to visualize the dynamics of the pseudo-structures across various tissues or developmental stages. Furthermore, this novel method would make it possible to revisit most Hi-C data accumulated in the public domain in the last decade.
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Affiliation(s)
- Diána Makai
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, 2462 Martonvásár, Hungary
| | - András Cseh
- Department of Molecular Breeding, Eötvös Loránd Research Network, Centre for Agricultural Research, 2462 Martonvásár, Hungary
| | - Adél Sepsi
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, 2462 Martonvásár, Hungary
| | - Szabolcs Makai
- Department of Molecular Breeding, Eötvös Loránd Research Network, Centre for Agricultural Research, 2462 Martonvásár, Hungary
- Department of Cereal Breeding, Eötvös Loránd Research Network, Centre for Agricultural Research, 2462 Martonvásár, Hungary
- Correspondence:
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Mehta IS, Riyahi K, Pereira RT, Meaburn KJ, Figgitt M, Kill IR, Eskiw CH, Bridger JM. Interphase Chromosomes in Replicative Senescence: Chromosome Positioning as a Senescence Biomarker and the Lack of Nuclear Motor-Driven Chromosome Repositioning in Senescent Cells. Front Cell Dev Biol 2021; 9:640200. [PMID: 34113611 PMCID: PMC8185894 DOI: 10.3389/fcell.2021.640200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 02/25/2021] [Indexed: 01/10/2023] Open
Abstract
This study demonstrates, and confirms, that chromosome territory positioning is altered in primary senescent human dermal fibroblasts (HDFs). The chromosome territory positioning pattern is very similar to that found in HDFs made quiescent either by serum starvation or confluence; but not completely. A few chromosomes are found in different locations. One chromosome in particular stands out, chromosome 10, which is located in an intermediate location in young proliferating HDFs, but is found at the nuclear periphery in quiescent cells and in an opposing location of the nuclear interior in senescent HDFs. We have previously demonstrated that individual chromosome territories can be actively and rapidly relocated, with 15 min, after removal of serum from the culture media. These chromosome relocations require nuclear motor activity through the presence of nuclear myosin 1β (NM1β). We now also demonstrate rapid chromosome movement in HDFs after heat-shock at 42°C. Others have shown that heat shock genes are actively relocated using nuclear motor protein activity via actin or NM1β (Khanna et al., 2014; Pradhan et al., 2020). However, this current study reveals, that in senescent HDFs, chromosomes can no longer be relocated to expected nuclear locations upon these two types of stimuli. This coincides with a entirely different organisation and distribution of NM1β within senescent HDFs.
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Affiliation(s)
- Ishita S Mehta
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom.,Tata Institute of Fundamental Research, Mumbai, India
| | - Kumars Riyahi
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom
| | - Rita Torres Pereira
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom
| | - Karen J Meaburn
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom
| | - Martin Figgitt
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom.,Department of Life Sciences, Birmingham City University, Birmingham, United Kingdom
| | - Ian R Kill
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom
| | - Christopher H Eskiw
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Joanna M Bridger
- Centre for Genome Engineering and Maintenance, Division of Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Kingston Lane, Brunel University London, Uxbridge, United Kingdom
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