1
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Attar AG, Paturej J, Banigan EJ, Erbaş A. Chromatin phase separation and nuclear shape fluctuations are correlated in a polymer model of the nucleus. Nucleus 2024; 15:2351957. [PMID: 38753956 DOI: 10.1080/19491034.2024.2351957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/28/2024] [Indexed: 05/18/2024] Open
Abstract
Abnormal cell nuclear shapes are hallmarks of diseases, including progeria, muscular dystrophy, and many cancers. Experiments have shown that disruption of heterochromatin and increases in euchromatin lead to nuclear deformations, such as blebs and ruptures. However, the physical mechanisms through which chromatin governs nuclear shape are poorly understood. To investigate how heterochromatin and euchromatin might govern nuclear morphology, we studied chromatin microphase separation in a composite coarse-grained polymer and elastic shell simulation model. By varying chromatin density, heterochromatin composition, and heterochromatin-lamina interactions, we show how the chromatin phase organization may perturb nuclear shape. Increasing chromatin density stabilizes the lamina against large fluctuations. However, increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations by a "wetting"-like interaction. In contrast, fluctuations are insensitive to heterochromatin's internal structure. Our simulations suggest that peripheral heterochromatin accumulation could perturb nuclear morphology, while nuclear shape stabilization likely occurs through mechanisms other than chromatin microphase organization.
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Affiliation(s)
- Ali Goktug Attar
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
| | | | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aykut Erbaş
- UNAM-National Nanotechnology Research Center and Institute of Materials Science & Nanotechnology, Bilkent University, Ankara, Turkey
- Institute of Physics, University of Silesia, Chorzów, Poland
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2
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Wang Z, Zhao N, Zhang S, Wang D, Wang S, Liu N. YEATS domain-containing protein GAS41 regulates nuclear shape by working in concert with BRD2 and the mediator complex in colorectal cancer. Pharmacol Res 2024; 206:107283. [PMID: 38964523 DOI: 10.1016/j.phrs.2024.107283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 06/21/2024] [Accepted: 06/22/2024] [Indexed: 07/06/2024]
Abstract
The maintenance of nuclear shape is essential for cellular homeostasis and disruptions in this process have been linked to various pathological conditions, including cancer, laminopathies, and aging. Despite the significance of nuclear shape, the precise molecular mechanisms controlling it are not fully understood. In this study, we have identified the YEATS domain-containing protein 4 (GAS41) as a previously unidentified factor involved in regulating nuclear morphology. Genetic ablation of GAS41 in colorectal cancer cells resulted in significant abnormalities in nuclear shape and inhibited cancer cell proliferation both in vitro and in vivo. Restoration experiments revealed that wild-type GAS41, but not a YEATS domain mutant devoid of histone H3 lysine 27 acetylation or crotonylation (H3K27ac/cr) binding, rescued the aberrant nuclear phenotypes in GAS41-deficient cells, highlighting the importance of GAS41's binding to H3K27ac/cr in nuclear shape regulation. Further experiments showed that GAS41 interacts with H3K27ac/cr to regulate the expression of key nuclear shape regulators, including LMNB1, LMNB2, SYNE4, and LEMD2. Mechanistically, GAS41 recruited BRD2 and the Mediator complex to gene loci of these regulators, promoting their transcriptional activation. Disruption of GAS41-H3K27ac/cr binding caused BRD2, MED14 and MED23 to dissociate from gene loci, leading to nuclear shape abnormalities. Overall, our findings demonstrate that GAS41 collaborates with BRD2 and the Mediator complex to control the expression of crucial nuclear shape regulators.
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Affiliation(s)
- Zhengmin Wang
- Department of Infectious Diseases and Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun 130021, China
| | - Nan Zhao
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Siwei Zhang
- Department of Pharmacology, College of Basic Medical Sciences, Jilin University, Changchun 130000, China
| | - Deyu Wang
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Shuai Wang
- Bethune Institute of Epigenetic Medicine, The First Hospital of Jilin University, Changchun 130021, China
| | - Nan Liu
- Department of Infectious Diseases and Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, The First Hospital of Jilin University, Changchun 130021, China.
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3
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Manivannan V, Inamdar MM, Padinhateeri R. Role of diffusion and reaction of the constituents in spreading of histone modification marks. PLoS Comput Biol 2024; 20:e1012235. [PMID: 38991050 PMCID: PMC11265668 DOI: 10.1371/journal.pcbi.1012235] [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: 12/29/2023] [Revised: 07/23/2024] [Accepted: 06/06/2024] [Indexed: 07/13/2024] Open
Abstract
Cells switch genes ON or OFF by altering the state of chromatin via histone modifications at specific regulatory locations along the chromatin polymer. These gene regulation processes are carried out by a network of reactions in which the histone marks spread to neighboring regions with the help of enzymes. In the literature, this spreading has been studied as a purely kinetic, non-diffusive process considering the interactions between neighboring nucleosomes. In this work, we go beyond this framework and study the spreading of modifications using a reaction-diffusion (RD) model accounting for the diffusion of the constituents. We quantitatively segregate the modification profiles generated from kinetic and RD models. The diffusion and degradation of enzymes set a natural length scale for limiting the domain size of modification spreading, and the resulting enzyme limitation is inherent in our model. We also demonstrate the emergence of confined modification domains without the explicit requirement of a nucleation site. We explore polymer compaction effects on spreading and show that single-cell domains may differ from averaged profiles. We find that the modification profiles from our model are comparable with existing H3K9me3 data of S. pombe.
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Affiliation(s)
- Vinoth Manivannan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Mandar M. Inamdar
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Mumbai, India
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4
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Chiu K, Berrada Y, Eskndir N, Song D, Fong C, Naughton S, Chen T, Moy S, Gyurmey S, James L, Ezeiruaku C, Capistran C, Lowey D, Diwanji V, Peterson S, Parakh H, Burgess AR, Probert C, Zhu A, Anderson B, Levi N, Gerlitz G, Packard MC, Dorfman KA, Bahiru MS, Stephens AD. CTCF is essential for proper mitotic spindle structure and anaphase segregation. Chromosoma 2024; 133:183-194. [PMID: 37728741 DOI: 10.1007/s00412-023-00810-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 08/11/2023] [Accepted: 09/08/2023] [Indexed: 09/21/2023]
Abstract
Mitosis is an essential process in which the duplicated genome is segregated equally into two daughter cells. CTCF has been reported to be present in mitosis and has a role in localizing CENP-E, but its importance for mitotic fidelity remains to be determined. To evaluate the importance of CTCF in mitosis, we tracked mitotic behaviors in wild-type and two different CTCF CRISPR-based genetic knockdowns. We find that knockdown of CTCF results in prolonged mitoses and failed anaphase segregation via time-lapse imaging of SiR-DNA. CTCF knockdown did not alter cell cycling or the mitotic checkpoint, which was activated upon nocodazole treatment. Immunofluorescence imaging of the mitotic spindle in CTCF knockdowns revealed disorganization via tri/tetrapolar spindles and chromosomes behind the spindle pole. Imaging of interphase nuclei showed that nuclear size increased drastically, consistent with failure to divide the duplicated genome in anaphase. Long-term inhibition of CNEP-E via GSK923295 recapitulates CTCF knockdown abnormal mitotic spindles with polar chromosomes and increased nuclear sizes. Population measurements of nuclear shape in CTCF knockdowns do not display decreased circularity or increased nuclear blebbing relative to wild-type. However, failed mitoses do display abnormal nuclear morphologies relative to successful mitoses, suggesting that population images do not capture individual behaviors. Thus, CTCF is important for both proper metaphase organization and anaphase segregation which impacts the size and shape of the interphase nucleus likely through its known role in recruiting CENP-E.
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Affiliation(s)
- Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Nebiyat Eskndir
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Dasol Song
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Claire Fong
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Sarah Naughton
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Tina Chen
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Savanna Moy
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Sarah Gyurmey
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Liam James
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Chimere Ezeiruaku
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Caroline Capistran
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Daniel Lowey
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Vedang Diwanji
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Samantha Peterson
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Harshini Parakh
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Ayanna R Burgess
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Cassandra Probert
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Annie Zhu
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Bryn Anderson
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Nehora Levi
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, 40700, Ariel, Israel
| | - Gabi Gerlitz
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, 40700, Ariel, Israel
| | - Mary C Packard
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Katherine A Dorfman
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Michael Seifu Bahiru
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
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5
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Eskndir N, Hossain M, Currey ML, Pho M, Berrada Y, Stephens AD. DNA damage causes ATM-dependent heterochromatin loss leading to nuclear softening, blebbing, and rupture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595790. [PMID: 38853925 PMCID: PMC11160674 DOI: 10.1101/2024.05.24.595790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The nucleus must maintain stiffness to protect the shape and integrity of the nucleus to ensure proper function. Defects in nuclear stiffness caused from chromatin and lamin perturbations produce abnormal nuclear shapes common in aging, heart disease, and cancer. Loss of nuclear shape via protrusions called blebs leads to nuclear rupture that is well-established to cause nuclear dysfunction, including DNA damage. However, it remains unknown how increased DNA damage affects nuclear stiffness, shape, and ruptures, which could create a negative feedback loop. To determine if increased DNA damage alters nuclear physical properties, we treated MEF cells with DNA damage drugs cisplatin and bleomycin. DNA damage drugs caused increased nuclear blebbing and rupture in interphase nuclei within a few hours and independent of mitosis. Micromanipulation force measurements reveal that DNA damage decreased chromatin-based nuclear mechanics but did not change lamin-based strain stiffening at long extensions relative to wild type. Immunofluorescence measurements of DNA damage treatments reveal the mechanism is an ATM-dependent decrease in heterochromatin leading to nuclear weaken, blebbing, and rupture which can be rescued upon ATM inhibition treatment. Thus, DNA damage drugs cause ATM-dependent heterochromatin loss resulting in nuclear softening, blebbing, and rupture.
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Affiliation(s)
- Nebiyat Eskndir
- Biology Department, University of Massachusetts Amherst, Amherst, MA
| | - Manseeb Hossain
- Biology Department, University of Massachusetts Amherst, Amherst, MA
| | - Marilena L Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA
| | - Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA
| | - Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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6
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Donoghue S, Wright J, Voss AK, Lockhart PJ, Amor DJ. The Mendelian disorders of chromatin machinery: Harnessing metabolic pathways and therapies for treatment. Mol Genet Metab 2024; 142:108360. [PMID: 38428378 DOI: 10.1016/j.ymgme.2024.108360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
The Mendelian disorders of chromatin machinery (MDCMs) represent a distinct subgroup of disorders that present with neurodevelopmental disability. The chromatin machinery regulates gene expression by a range of mechanisms, including by post-translational modification of histones, responding to histone marks, and remodelling nucleosomes. Some of the MDCMs that impact on histone modification may have potential therapeutic interventions. Two potential treatment strategies are to enhance the intracellular pool of metabolites that can act as substrates for histone modifiers and the use of medications that may inhibit or promote the modification of histone residues to influence gene expression. In this article we discuss the influence and potential treatments of histone modifications involving histone acetylation and histone methylation. Genomic technologies are facilitating earlier diagnosis of many Mendelian disorders, providing potential opportunities for early treatment from infancy. This has parallels with how inborn errors of metabolism have been afforded early treatment with newborn screening. Before this promise can be fulfilled, we require greater understanding of the biochemical fingerprint of these conditions, which may provide opportunities to supplement metabolites that can act as substrates for chromatin modifying enzymes. Importantly, understanding the metabolomic profile of affected individuals may also provide disorder-specific biomarkers that will be critical for demonstrating efficacy of treatment, as treatment response may not be able to be accurately assessed by clinical measures.
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Affiliation(s)
- Sarah Donoghue
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Biochemical Genetics, Victorian Clinical Genetics Services, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia.
| | - Jordan Wright
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - Anne K Voss
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3052, Australia
| | - Paul J Lockhart
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - David J Amor
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
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7
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Buisson J, Zhang X, Zambelli T, Lavalle P, Vautier D, Rabineau M. Reverse Mechanotransduction: Driving Chromatin Compaction to Decompaction Increases Cell Adhesion Strength and Contractility. NANO LETTERS 2024; 24:4279-4290. [PMID: 38546049 DOI: 10.1021/acs.nanolett.4c00732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Mechanical extracellular signals elicit chromatin remodeling via the mechanotransduction pathway, thus determining cellular function. However, the reverse pathway is an open question: does chromatin remodeling shape cells, regulating their adhesion strength? With fluidic force microscopy, we can directly measure the adhesion strength of epithelial cells by driving chromatin compaction to decompaction with chromatin remodelers. We observe that chromatin compaction, induced by performing histone acetyltransferase inhibition or ATP depletion, leads to a reduction in nuclear volume, disrupting actin cytoskeleton and focal adhesion assembly, and ultimately decreases in cell adhesion strength and traction force. Conversely, when chromatin decompaction is drived by removing the remodelers, cells recover their original shape, adhesion strength, and traction force. During chromatin decompaction, cells use depolymerized proteins to restore focal adhesion assemblies rather than neo-synthesized cytoskeletal proteins. We conclude that chromatin remodeling shapes cells, regulating adhesion strength through a reverse mechanotransduction pathway from the nucleus to the cell surface involving RhoA activation.
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Affiliation(s)
- Julie Buisson
- Inserm UMR_S 1121, CNRS EMR 7003, Université de Strasbourg, Biomaterials and Bioengineering, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg F-67000, France
| | - Xinyu Zhang
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich 8092, Switzerland
| | - Tomaso Zambelli
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Zurich 8092, Switzerland
| | - Philippe Lavalle
- Inserm UMR_S 1121, CNRS EMR 7003, Université de Strasbourg, Biomaterials and Bioengineering, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg F-67000, France
- SPARTHA Medical SAS, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg F-67000, France
| | - Dominique Vautier
- Inserm UMR_S 1121, CNRS EMR 7003, Université de Strasbourg, Biomaterials and Bioengineering, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg F-67000, France
| | - Morgane Rabineau
- Inserm UMR_S 1121, CNRS EMR 7003, Université de Strasbourg, Biomaterials and Bioengineering, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg F-67000, France
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Wu ZP, Bloom KS, Forest MG, Cao XZ. Transient crosslinking controls the condensate formation pathway within chromatin networks. Phys Rev E 2024; 109:L042401. [PMID: 38755828 PMCID: PMC11137846 DOI: 10.1103/physreve.109.l042401] [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: 09/10/2023] [Accepted: 02/26/2024] [Indexed: 05/18/2024]
Abstract
The network structure of densely packed chromatin within the nucleus of eukaryotic cells acts in concert with nonequilibrium processes. Using statistical physics simulations, we explore the control provided by transient crosslinking of the chromatin network by structural-maintenance-of-chromosome (SMC) proteins over (i) the physical properties of the chromatin network and (ii) condensate formation of embedded molecular species. We find that the density and lifetime of transient SMC crosslinks regulate structural relaxation modes and tune the sol-vs-gel state of the chromatin network, which imparts control over the kinetic pathway to condensate formation. Specifically, lower density, shorter-lived crosslinks induce sollike networks and a droplet-fusion pathway, whereas higher density, longer-lived crosslinks induce gellike networks and an Ostwald-ripening pathway.
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Affiliation(s)
- Zong-Pei Wu
- Department of Physics at Xiamen University, Xiamen 361005, P.R. China
| | - Kerry S. Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - M. Gregory Forest
- Departments of Mathematics, Applied Physical Sciences and Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Xue-Zheng Cao
- Department of Physics at Xiamen University, Xiamen 361005, P.R. China
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Sun X, Wu L, Du L, Xu W, Han M. Targeting the organelle for radiosensitization in cancer radiotherapy. Asian J Pharm Sci 2024; 19:100903. [PMID: 38590796 PMCID: PMC10999375 DOI: 10.1016/j.ajps.2024.100903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/29/2023] [Accepted: 01/16/2024] [Indexed: 04/10/2024] Open
Abstract
Radiotherapy is a well-established cytotoxic therapy for local solid cancers, utilizing high-energy ionizing radiation to destroy cancer cells. However, this method has several limitations, including low radiation energy deposition, severe damage to surrounding normal cells, and high tumor resistance to radiation. Among various radiotherapy methods, boron neutron capture therapy (BNCT) has emerged as a principal approach to improve the therapeutic ratio of malignancies and reduce lethality to surrounding normal tissue, but it remains deficient in terms of insufficient boron accumulation as well as short retention time, which limits the curative effect. Recently, a series of radiosensitizers that can selectively accumulate in specific organelles of cancer cells have been developed to precisely target radiotherapy, thereby reducing side effects of normal tissue damage, overcoming radioresistance, and improving radiosensitivity. In this review, we mainly focus on the field of nanomedicine-based cancer radiotherapy and discuss the organelle-targeted radiosensitizers, specifically including nucleus, mitochondria, endoplasmic reticulum and lysosomes. Furthermore, the organelle-targeted boron carriers used in BNCT are particularly presented. Through demonstrating recent developments in organelle-targeted radiosensitization, we hope to provide insight into the design of organelle-targeted radiosensitizers for clinical cancer treatment.
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Affiliation(s)
- Xiaoyan Sun
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems, Zhejiang University, Hangzhou 310058, China
| | - Linjie Wu
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems, Zhejiang University, Hangzhou 310058, China
| | - Lina Du
- Department of Pharmaceutical Sciences, Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Wenhong Xu
- Department of Radiation Oncology, Key Laboratory of Cancer Prevention and Intervention, The Second Afliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310058, China
| | - Min Han
- Institute of Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
- Department of Radiation Oncology, Key Laboratory of Cancer Prevention and Intervention, The Second Afliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310058, China
- Hangzhou Institute of Innovative Medicine, Zhejiang University, Hangzhou 310058, China
- Jinhua Institute of Zhejiang University, Jinhua 321299, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems, Zhejiang University, Hangzhou 310058, China
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10
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Bairamukov VY, Kovalev RA, Ankudinov AV, Pantina RA, Fedorova ND, Bukatin AS, Grigoriev SV, Varfolomeeva EY. Alterations in the chromatin packaging, driven by transcriptional activity, revealed by AFM. Biochim Biophys Acta Gen Subj 2024; 1868:130568. [PMID: 38242181 DOI: 10.1016/j.bbagen.2024.130568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/21/2024]
Abstract
BACKGROUND The gene expression differs in the nuclei of normal and malignant mammalian cells, and transcription is a critical initial step, which defines the difference. The mechanical properties of transcriptionally active chromatin are still poorly understood. Recently we have probed transcriptionally active chromatin of the nuclei subjected to mechanical stress, by Atomic Force Microscopy (AFM) [1]. Nonetheless, a systematic study of the phenomenon is needed. METHODS Nuclei were deformed and studied by AFM. Non-deformed nuclei were studied by fluorescence confocal microscopy. Their transcriptional activity was studied by RNA electrophoresis. RESULTS The malignant nuclei under the study were stable to deformation and assembled of 100-300 nm beads-like units, while normal cell nuclei were prone to deformation. The difference in stability to deformation of the nuclei correlated with DNA supercoiling, and transcription-depended units were responsive to supercoils breakage. The inhibitors of the topoisomerases I and II disrupted supercoiling and made the malignant nucleus prone to deformation. Cell nuclei treatment with histone deacetylase inhibitors (HDACIs) preserved the mechanical stability of deformed malignant nuclei and, at the same time, made it possible to observe chromatin decondensation up to 20-60 nm units. The AFM results were supplemented with confocal microscopy and RNA electrophoresis data. CONCLUSIONS Self-assembly of transcriptionally active chromatin and its decondensation, driven by DNA supercoiling-dependent rigidity, was visualized by AFM in the mechanically deformed nuclei. GENERAL SIGNIFICANCE We demonstrated that supercoiled DNA defines the transcription mechanics, and hypothesized the nuclear mechanics in vivo should depend on the chromatin architecture.
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Affiliation(s)
- V Yu Bairamukov
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia.
| | - R A Kovalev
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia
| | - A V Ankudinov
- The Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 26, Politekhnicheskaya, 194021 Saint Petersburg, Russia
| | - R A Pantina
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia
| | - N D Fedorova
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia
| | - A S Bukatin
- Alferov Saint Petersburg National Research Academic University of the Russian Academy of Sciences, 8/3, Khlopina St., 194021 Saint Petersburg, Russia
| | - S V Grigoriev
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia
| | - E Yu Varfolomeeva
- Petersburg Nuclear Physics Institute Named by B.P. Konstantinov of NRC "Kurchatov Institute", 1, Orlova Roshcha, 188300 Gatchina, Russia
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11
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Pujadas Liwag EM, Acosta N, Almassalha LM, Su YP, Gong R, Kanemaki MT, Stephens AD, Backman V. Nuclear blebs are associated with destabilized chromatin packing domains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587095. [PMID: 38585954 PMCID: PMC10996693 DOI: 10.1101/2024.03.28.587095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Disrupted nuclear shape is associated with multiple pathological processes including premature aging disorders, cancer-relevant chromosomal rearrangements, and DNA damage. Nuclear blebs (i.e., herniations of the nuclear envelope) have been induced by (1) nuclear compression, (2) nuclear migration (e.g., cancer metastasis), (3) actin contraction, (4) lamin mutation or depletion, and (5) heterochromatin enzyme inhibition. Recent work has shown that chromatin transformation is a hallmark of bleb formation, but the transformation of higher-order structures in blebs is not well understood. As higher-order chromatin has been shown to assemble into nanoscopic packing domains, we investigated if (1) packing domain organization is altered within nuclear blebs and (2) if alteration in packing domain structure contributed to bleb formation. Using Dual-Partial Wave Spectroscopic microscopy, we show that chromatin packing domains within blebs are transformed both by B-type lamin depletion and the inhibition of heterochromatin enzymes compared to the nuclear body. Pairing these results with single-molecule localization microscopy of constitutive heterochromatin, we show fragmentation of nanoscopic heterochromatin domains within bleb domains. Overall, these findings indicate that translocation into blebs results in a fragmented higher-order chromatin structure. SUMMARY STATEMENT Nuclear blebs are linked to various pathologies, including cancer and premature aging disorders. We investigate alterations in higher-order chromatin structure within blebs, revealing fragmentation of nanoscopic heterochromatin domains.
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12
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Conforti JM, Ziegler AM, Worth CS, Nambiar AM, Bailey JT, Taube JH, Gallagher ES. Differences in Protein Capture by SP3 and SP4 Demonstrate Mechanistic Insights of Proteomics Clean-up Techniques. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.13.584881. [PMID: 38559195 PMCID: PMC10980087 DOI: 10.1101/2024.03.13.584881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The goal of proteomics experiments is to identify proteins to observe changes in cellular processes and diseases. One challenge in proteomics is the removal of contaminants following protein extraction, which can limit protein identification. Single-pot, solid-phase-enhanced sample preparation (SP3) is a clean-up technique in which proteins are captured on carboxylate-modified particles through a proposed hydrophilic-interaction-liquid-chromatography (HILIC)-like mechanism. However, recent results have suggested that proteins are captured in SP3 due to a protein-aggregation mechanism. Thus, solvent precipitation, single-pot, solid-phase-enhanced sample preparation (SP4) is a newer clean-up technique that employs protein-aggregation to capture proteins without modified particles. SP4 has previously enriched low-solubility proteins, though differences in protein capture could affect which proteins are detected and identified. We hypothesize that the mechanisms of capture for SP3 and SP4 are distinct. Herein, we assess the proteins identified and enriched using SP3 versus SP4 for MCF7 subcellular fractions and correlate protein capture in each method to protein hydrophobicity. Our results indicate that SP3 captures more hydrophilic proteins through a combination of HILIC-like and protein-aggregation mechanisms, while SP4 captures more hydrophobic proteins through a protein-aggregation mechanism. From these results, we recommend clean-up techniques based on protein-sample hydrophobicity to yield high proteome coverage in biological samples.
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Affiliation(s)
- Jessica M. Conforti
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Amanda M. Ziegler
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Charli S. Worth
- Department of Biology, Baylor University, One Bear Place #97388, Waco, Texas 76798, United States
| | - Adhwaitha M. Nambiar
- Department of Biology, Baylor University, One Bear Place #97388, Waco, Texas 76798, United States
| | - Jacob T. Bailey
- Department of Biology, Baylor University, One Bear Place #97388, Waco, Texas 76798, United States
| | - Joseph H. Taube
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
- Department of Biology, Baylor University, One Bear Place #97388, Waco, Texas 76798, United States
| | - Elyssia S. Gallagher
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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13
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Pho M, Berrada Y, Gunda A, Stephens AD. Nuclear shape is affected differentially by loss of lamin A, lamin C, or both lamin A and C. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001103. [PMID: 38440331 PMCID: PMC10910297 DOI: 10.17912/micropub.biology.001103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/16/2024] [Accepted: 02/14/2024] [Indexed: 03/06/2024]
Abstract
Lamin intermediate filaments form a peripheral meshwork to support nuclear shape and function. Knockout of the LMNA gene that encodes for both lamin A and C results in an abnormally shaped nucleus. To determine the relative contribution of lamin A and C to nuclear shape, we measured nuclear blebbing and circular deviation in separate lamin A and lamin C knockdown and LMNA-/- stable cells. Lamin A knockdown increased nuclear blebbing while loss of lamin A, C, or both increased circular deviation. Overall, loss of lamin A, lamin C or both lamin A/C affect nuclear shape differentially.
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Affiliation(s)
- Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst Center, Massachusetts, United States
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst Center, Massachusetts, United States
| | - Aachal Gunda
- Biology Department, University of Massachusetts Amherst, Amherst Center, Massachusetts, United States
| | - Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst Center, Massachusetts, United States
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst Center, Massachusetts, United States
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14
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Bunner S, Prince K, Srikrishna K, Pujadas EM, McCarthy AA, Kuklinski A, Jackson O, Pellegrino P, Jagtap S, Eweka I, Lawlor C, Eastin E, Yas G, Aiello J, LaPointe N, von Blucher IS, Hardy J, Chen J, Backman V, Janssen A, Packard M, Dorfman K, Almassalha L, Bahiru MS, Stephens AD. DNA density is a better indicator of a nuclear bleb than lamin B loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579152. [PMID: 38370828 PMCID: PMC10871186 DOI: 10.1101/2024.02.06.579152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Nuclear blebs are herniations of the nucleus that occur in diseased nuclei that cause nuclear rupture leading to cellular dysfunction. Chromatin and lamins are two of the major structural components of the nucleus that maintain its shape and function, but their relative roles in nuclear blebbing remain elusive. Lamin B is reported to be lost in blebs by qualitative data while quantitative studies reveal a spectrum of lamin B levels in nuclear blebs dependent on perturbation and cell type. Chromatin has been reported to be decreased or de-compacted in nuclear blebs, but again the data are not conclusive. To determine the composition of nuclear blebs, we compared the immunofluorescence intensity of lamin B and DNA in the main nucleus body and nuclear bleb across cell types and perturbations. Lamin B nuclear bleb levels varied drastically across MEF wild type and chromatin or lamins perturbations, HCT116 lamin B1-GFP imaging, and human disease model cells of progeria and prostate cancer. However, DNA concentration was consistently decreased to about half that of the main nucleus body across all measured conditions. Using Partial Wave Spectroscopic (PWS) microscopy to measure chromatin density in the nuclear bleb vs body we find similar results that DNA is consistently less dense in nuclear blebs. Thus, our data spanning many different cell types and perturbations supports that decreased DNA is a better marker of a nuclear bleb than lamin B levels that vary widely.
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Affiliation(s)
- Samantha Bunner
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Kelsey Prince
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Karan Srikrishna
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Emily Marie Pujadas
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- IBIS Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
| | | | - Anna Kuklinski
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Olivia Jackson
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Pedro Pellegrino
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Shrushti Jagtap
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Imuetiyan Eweka
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Colman Lawlor
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Emma Eastin
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Griffin Yas
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Julianna Aiello
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Nathan LaPointe
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | | | - Jillian Hardy
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Jason Chen
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Anne Janssen
- School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Mary Packard
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Katherine Dorfman
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
| | - Luay Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Michael Seifu Bahiru
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
- Program in Neuroscience and Behavior, University of Massachusetts, Amherst, MA 01003, USA
| | - A. D. Stephens
- Biology department, University of Massachusetts Amherst, Amherst, MA. 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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15
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Pho M, Berrada Y, Gunda A, Lavallee A, Chiu K, Padam A, Currey ML, Stephens AD. Actin contraction controls nuclear blebbing and rupture independent of actin confinement. Mol Biol Cell 2024; 35:ar19. [PMID: 38088876 PMCID: PMC10881147 DOI: 10.1091/mbc.e23-07-0292] [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: 07/27/2023] [Revised: 11/03/2023] [Accepted: 11/27/2023] [Indexed: 01/14/2024] Open
Abstract
The nucleus is a mechanically stable compartment of the cell that contains the genome and performs many essential functions. Nuclear mechanical components chromatin and lamins maintain nuclear shape, compartmentalization, and function by resisting antagonistic actin contraction and confinement. Studies have yet to compare chromatin and lamins perturbations side-by-side as well as modulated actin contraction while holding confinement constant. To accomplish this, we used nuclear localization signal green fluorescent protein to measure nuclear shape and rupture in live cells with chromatin and lamin perturbations. We then modulated actin contraction while maintaining actin confinement measured by nuclear height. Wild type, chromatin decompaction, and lamin B1 null present bleb-based nuclear deformations and ruptures dependent on actin contraction and independent of actin confinement. Actin contraction inhibition by Y27632 decreased nuclear blebbing and ruptures while activation by CN03 increased rupture frequency. Lamin A/C null results in overall abnormal shape also reliant on actin contraction, but similar blebs and ruptures as wild type. Increased DNA damage is caused by nuclear blebbing or abnormal shape which can be relieved by inhibition of actin contraction which rescues nuclear shape and decreases DNA damage levels in all perturbations. Thus, actin contraction drives nuclear blebbing, bleb-based ruptures, and abnormal shape independent of changes in actin confinement.
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Affiliation(s)
- Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Aachal Gunda
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Anya Lavallee
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Arimita Padam
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Marilena L. Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003
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16
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Attar AG, Paturej J, Banigan EJ, Erbas A. Chromatin phase separation and nuclear shape fluctuations are correlated in a polymer model of the nucleus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.16.571697. [PMID: 38168411 PMCID: PMC10760070 DOI: 10.1101/2023.12.16.571697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Abnormalities in the shapes of mammalian cell nuclei are hallmarks of a variety of diseases, including progeria, muscular dystrophy, and various cancers. Experiments have shown that there is a causal relationship between chromatin organization and nuclear morphology. Decreases in heterochromatin levels, perturbations to heterochromatin organization, and increases in euchromatin levels all lead to misshapen nuclei, which exhibit deformations, such as nuclear blebs and nuclear ruptures. However, the polymer physical mechanisms of how chromatin governs nuclear shape and integrity are poorly understood. To investigate how heterochromatin and euchromatin, which are thought to microphase separate in vivo , govern nuclear morphology, we implemented a composite coarse-grained polymer and elastic shell model. By varying chromatin volume fraction (density), heterochromatin levels and structure, and heterochromatin-lamina interactions, we show how the spatial organization of chromatin polymer phases within the nucleus could perturb nuclear shape in some scenarios. Increasing the volume fraction of chromatin in the cell nucleus stabilizes the nuclear lamina against large fluctuations. However, surprisingly, we find that increasing heterochromatin levels or heterochromatin-lamina interactions enhances nuclear shape fluctuations in our simulations by a "wetting"-like interaction. In contrast, shape fluctuations are largely insensitive to the internal structure of the heterochromatin, such as the presence or absence of chromatin-chromatin crosslinks. Therefore, our simulations suggest that heterochromatin accumulation at the nuclear periphery could perturb nuclear morphology in a nucleus or nuclear region that is sufficiently soft, while stabilization of the nucleus via heterochromatin likely occurs through mechanisms other than chromatin microphase organization.
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17
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Chen P, Mishra S, Prabha H, Sengupta S, Levy DL. Nuclear growth and import can be uncoupled. Mol Biol Cell 2024; 35:ar1. [PMID: 37903226 PMCID: PMC10881164 DOI: 10.1091/mbc.e23-04-0138] [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: 04/21/2023] [Revised: 09/29/2023] [Accepted: 10/18/2023] [Indexed: 11/01/2023] Open
Abstract
What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while import is required for nuclear growth, nuclear growth and import can be uncoupled when chromatin structure is manipulated. Nuclei treated with micrococcal nuclease to fragment DNA grew slowly despite exhibiting little to no change in import rates. Nuclei assembled around axolotl chromatin with 20-fold more DNA than Xenopus grew larger but imported more slowly. Treating nuclei with reagents known to alter histone methylation or acetylation caused nuclei to grow less while still importing to a similar extent or to grow larger without significantly increasing import. Nuclear growth but not import was increased in live sea urchin embryos treated with the DNA methylator N-nitrosodimethylamine. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, we observed that nuclear blebs expanded preferentially at sites of high chromatin density and lamin addition, whereas small Benzonase-treated nuclei lacking DNA exhibited reduced lamin incorporation into the nuclear envelope. In summary, we report experimental conditions where nuclear import is not sufficient to drive nuclear growth, hypothesizing that this uncoupling is a result of altered chromatin structure.
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Affiliation(s)
- Pan Chen
- Department of Biochemistry and Molecular Biology and Zhejiang Key Laboratory of Pathophysiology, School of Basic Medical Sciences, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Haritha Prabha
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Sourabh Sengupta
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071
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18
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Spegg V, Altmeyer M. Genome maintenance meets mechanobiology. Chromosoma 2024; 133:15-36. [PMID: 37581649 PMCID: PMC10904543 DOI: 10.1007/s00412-023-00807-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Genome stability is key for healthy cells in healthy organisms, and deregulated maintenance of genome integrity is a hallmark of aging and of age-associated diseases including cancer and neurodegeneration. To maintain a stable genome, genome surveillance and repair pathways are closely intertwined with cell cycle regulation and with DNA transactions that occur during transcription and DNA replication. Coordination of these processes across different time and length scales involves dynamic changes of chromatin topology, clustering of fragile genomic regions and repair factors into nuclear repair centers, mobilization of the nuclear cytoskeleton, and activation of cell cycle checkpoints. Here, we provide a general overview of cell cycle regulation and of the processes involved in genome duplication in human cells, followed by an introduction to replication stress and to the cellular responses elicited by perturbed DNA synthesis. We discuss fragile genomic regions that experience high levels of replication stress, with a particular focus on telomere fragility caused by replication stress at the ends of linear chromosomes. Using alternative lengthening of telomeres (ALT) in cancer cells and ALT-associated PML bodies (APBs) as examples of replication stress-associated clustered DNA damage, we discuss compartmentalization of DNA repair reactions and the role of protein properties implicated in phase separation. Finally, we highlight emerging connections between DNA repair and mechanobiology and discuss how biomolecular condensates, components of the nuclear cytoskeleton, and interfaces between membrane-bound organelles and membraneless macromolecular condensates may cooperate to coordinate genome maintenance in space and time.
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Affiliation(s)
- Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland.
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19
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Hara Y. Physical forces modulate interphase nuclear size. Curr Opin Cell Biol 2023; 85:102253. [PMID: 37801797 DOI: 10.1016/j.ceb.2023.102253] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/11/2023] [Accepted: 09/07/2023] [Indexed: 10/08/2023]
Abstract
The eukaryotic nucleus exhibits remarkable plasticity in size, adjusting dynamically to changes in cellular conditions such as during development and differentiation, and across species. Traditionally, the supply of structural constituents to the nuclear envelope has been proposed as the principal determinant of nuclear size. However, recent experimental and theoretical analyses have provided an alternative perspective, which emphasizes the crucial role of physical forces such as osmotic pressure and chromatin repulsion forces in regulating nuclear size. These forces can be modulated by the molecular profiles that traverse the nuclear envelope and assemble in the macromolecular complex. This leads to a new paradigm wherein multiple nuclear macromolecules that are not limited to only the structural constituents of the nuclear envelope, are involved in the control of nuclear size and related functions.
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Affiliation(s)
- Yuki Hara
- Evolutionary Cell Biology Laboratory, Faculty of Science, Yamaguchi University, Yoshida 1677-1, Yamaguchi City, 753-8512, Japan.
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20
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Berg IK, Currey ML, Gupta S, Berrada Y, Nguyen BV, Pho M, Patteson AE, Schwarz JM, Banigan EJ, Stephens AD. Transcription inhibition suppresses nuclear blebbing and rupture independently of nuclear rigidity. J Cell Sci 2023; 136:jcs261547. [PMID: 37756607 PMCID: PMC10660790 DOI: 10.1242/jcs.261547] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Chromatin plays an essential role in the nuclear mechanical response and determining nuclear shape, which maintain nuclear compartmentalization and function. However, major genomic functions, such as transcription activity, might also impact cell nuclear shape via blebbing and rupture through their effects on chromatin structure and dynamics. To test this idea, we inhibited transcription with several RNA polymerase II inhibitors in wild-type cells and perturbed cells that presented increased nuclear blebbing. Transcription inhibition suppressed nuclear blebbing for several cell types, nuclear perturbations and transcription inhibitors. Furthermore, transcription inhibition suppressed nuclear bleb formation, bleb stabilization and bleb-based nuclear ruptures. Interestingly, transcription inhibition did not alter the histone H3 lysine 9 (H3K9) modification state, nuclear rigidity, and actin compression and contraction, which typically control nuclear blebbing. Polymer simulations suggested that RNA polymerase II motor activity within chromatin could drive chromatin motions that deform the nuclear periphery. Our data provide evidence that transcription inhibition suppresses nuclear blebbing and rupture, in a manner separate and distinct from chromatin rigidity.
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Affiliation(s)
- Isabel K. Berg
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Marilena L. Currey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarthak Gupta
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Bao V. Nguyen
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Mai Pho
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Alison E. Patteson
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
| | - J. M. Schwarz
- Department of Physics and BioInspired Syracuse, Syracuse University, Syracuse, NY 13244, USA
- Indian Creek Farm, Ithaca, NY 14850, USA
| | - Edward J. Banigan
- Institute of Medical Engineering & Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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21
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Bastianello G, Foiani M. Mechanisms controlling the mechanical properties of the nuclei. Curr Opin Cell Biol 2023; 84:102222. [PMID: 37619290 DOI: 10.1016/j.ceb.2023.102222] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/26/2023]
Abstract
The mechanical properties of the nucleus influence different cellular and nuclear functions and have relevant implications for several human diseases. The nucleus protects genetic information while acting as a mechano-sensory hub in response to internal and external forces. Cells have evolved mechano-transduction signaling to respond to physical cellular and nuclear perturbations and adopted a multitude of molecular pathways to maintain nuclear shape stability and prevent morphological abnormalities of the nucleus. Here we describe those key biological processes that control nuclear mechanics and discuss emerging perspectives on the mechanobiology of the nucleus as a diagnostic tool and clinical target.
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Affiliation(s)
- Giulia Bastianello
- IFOM, The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Oncology and Haemato-Oncology Department, University of Milan, Milan 20122, Italy.
| | - Marco Foiani
- IFOM, The FIRC Institute of Molecular Oncology, Milan 20139, Italy; Oncology and Haemato-Oncology Department, University of Milan, Milan 20122, Italy.
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22
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Baldini F, Zeaiter L, Diab F, Zbeeb H, Cuneo L, Pagano A, Portincasa P, Diaspro A, Vergani L. Nuclear and chromatin rearrangement associate to epigenome and gene expression changes in a model of in vitro adipogenesis and hypertrophy. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159368. [PMID: 37499858 DOI: 10.1016/j.bbalip.2023.159368] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/07/2023] [Accepted: 07/19/2023] [Indexed: 07/29/2023]
Abstract
Hypertrophy of adipocytes represents the main cause of obesity. We investigated in vitro the changes associated with adipocyte differentiation and hypertrophy focusing on the nuclear morphometry and chromatin epigenetic remodelling. The 3 T3-L1 pre-adipocytes were firstly differentiated into mature adipocytes, then cultured with long-chain fatty acids to induce hypertrophy. Confocal and super-resolution stimulation emission depletion (STED) microscopy combined with ELISA assays allowed us to explore nuclear architecture, chromatin distribution and epigenetic modifications. In each condition, we quantified the triglyceride accumulation, the mRNA expression of adipogenesis and dysfunction markers, the release of five pro-inflammatory cytokines. Confocal microscopy revealed larger volume and less elongated shape of the nuclei in both mature and hypertrophic cells respect to pre-adipocytes, and a trend toward reduced chromatin compaction. Compared to mature adipocytes, the hypertrophic phenotype showed larger triglyceride content, increased PPARγ expression reduced IL-1a release, and up-regulation of a pool of genes markers for adipose tissue dysfunction. Moreover, a remodelling of both epigenome and chromatin organization was observed in hypertrophic adipocytes, with an increase in the average fluorescence of H3K9 acetylated domains in parallel with the increase in KAT2A expression, and a global hypomethylation of DNA. These findings making light on the nuclear changes during adipocyte differentiation and hypertrophy might help the strategies for treating obesity and metabolic complications.
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Affiliation(s)
- Francesca Baldini
- Nanoscopy, Istituto Italiano Tecnologia, Via Enrico Melen 83, 16152, Genova, Italy
| | - Lama Zeaiter
- Nanoscopy, Istituto Italiano Tecnologia, Via Enrico Melen 83, 16152, Genova, Italy; Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132, Genova, Italy
| | - Farah Diab
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132, Genova, Italy
| | - Hawraa Zbeeb
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132, Genova, Italy
| | - Lisa Cuneo
- Nanoscopy, Istituto Italiano Tecnologia, Via Enrico Melen 83, 16152, Genova, Italy; Department of Physics (DIFILAB), University of Genoa, Via Dodecaneso 33, 16146, Genoa, Italy
| | - Aldo Pagano
- DIMES, Department of Experimental Medicine, University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Piero Portincasa
- Clinica Medica "A. Murri", Department of Biomedical Sciences and Human Oncology, University of Bari, Medical School, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | - Alberto Diaspro
- Nanoscopy, Istituto Italiano Tecnologia, Via Enrico Melen 83, 16152, Genova, Italy; Department of Physics (DIFILAB), University of Genoa, Via Dodecaneso 33, 16146, Genoa, Italy
| | - Laura Vergani
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132, Genova, Italy.
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23
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Liu JX, Haataja MP, Košmrlj A, Datta SS, Arnold CB, Priestley RD. Liquid-liquid phase separation within fibrillar networks. Nat Commun 2023; 14:6085. [PMID: 37770446 PMCID: PMC10539382 DOI: 10.1038/s41467-023-41528-8] [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: 02/14/2023] [Accepted: 09/06/2023] [Indexed: 09/30/2023] Open
Abstract
Complex fibrillar networks mediate liquid-liquid phase separation of biomolecular condensates within the cell. Mechanical interactions between these condensates and the surrounding networks are increasingly implicated in the physiology of the condensates and yet, the physical principles underlying phase separation within intracellular media remain poorly understood. Here, we elucidate the dynamics and mechanics of liquid-liquid phase separation within fibrillar networks by condensing oil droplets within biopolymer gels. We find that condensates constrained within the network pore space grow in abrupt temporal bursts. The subsequent restructuring of condensates and concomitant network deformation is contingent on the fracture of network fibrils, which is determined by a competition between condensate capillarity and network strength. As a synthetic analog to intracellular phase separation, these results further our understanding of the mechanical interactions between biomolecular condensates and fibrillar networks in the cell.
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Affiliation(s)
- Jason X Liu
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Mikko P Haataja
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Andrej Košmrlj
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Sujit S Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Craig B Arnold
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ, 08544, USA
- Princeton Materials Institute, Princeton University, Princeton, NJ, 08544, USA
| | - Rodney D Priestley
- Princeton Materials Institute, Princeton University, Princeton, NJ, 08544, USA.
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA.
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24
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Li P, Shang X, Jiao Q, Mi Q, Zhu M, Ren Y, Li J, Li L, Liu J, Wang C, Shi Y, Wang Y, Du L. Alteration of chromatin high-order conformation associated with oxaliplatin resistance acquisition in colorectal cancer cells. EXPLORATION (BEIJING, CHINA) 2023; 3:20220136. [PMID: 37933235 PMCID: PMC10624369 DOI: 10.1002/exp.20220136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 03/24/2023] [Indexed: 11/08/2023]
Abstract
Oxaliplatin is a first-line chemotherapy drug widely adopted in colorectal cancer (CRC) treatment. However, a large proportion of patients tend to become resistant to oxaliplatin, causing chemotherapy to fail. At present, researches on oxaliplatin resistance mainly focus on the genetic and epigenetic alterations during cancer evolution, while the characteristics of high-order three-dimensional (3D) conformation of genome are yet to be explored. In order to investigate the chromatin conformation alteration during oxaliplatin resistance, we performed multi-omics study by combining DLO Hi-C, ChIP-seq as well as RNA-seq technologies on the established oxaliplatin-resistant cell line HCT116-OxR, as well as the control cell line HCT116. The results indicate that 19.33% of the genome regions have A/B compartments transformation after drug resistance, further analysis of the genes converted by A/B compartments reveals that the acquisition of oxaliplatin resistance in tumor cells is related to the reduction of reactive oxygen species and enhanced metastatic capacity. Our research reveals the spatial chromatin structural difference between CRC cells and oxaliplatin resistant cells based on the DLO Hi-C and other epigenetic omics experiments. More importantly, we provide potential targets for oxaliplatin-resistant cancer treatment and a new way to investigate drug resistance behavior under the perspective of 3D genome alteration.
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Affiliation(s)
- Peilong Li
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Xueying Shang
- Key Laboratory of Systems Biomedicine, Shanghai Center for Systems BiomedicineShanghai Jiao Tong UniversityShanghaiChina
| | - Qinlian Jiao
- Shandong Quality Inspection Center for Medical DevicesJinanShandongChina
| | - Qi Mi
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Mengqian Zhu
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Yidan Ren
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Juan Li
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Li Li
- Wuhan GeneCreate Biological Engineering Co., LtdWuhanHubeiChina
| | - Jin Liu
- Wuhan GeneCreate Biological Engineering Co., LtdWuhanHubeiChina
| | - Chuanxin Wang
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Yi Shi
- Bio‐X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric DisordersShanghai Jiao Tong UniversityShanghaiChina
- Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research CenterShanghai Jiao Tong UniversityShanghaiChina
- School of Information TechnologiesUniversity of SydneySydneyNew South WalesAustralia
| | - Yunshan Wang
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
| | - Lutao Du
- Department of Clinical LaboratoryThe Second Hospital of Shandong UniversityJinanShandongChina
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25
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Introini V, Kidiyoor GR, Porcella G, Cicuta P, Cosentino Lagomarsino M. Centripetal nuclear shape fluctuations associate with chromatin condensation in early prophase. Commun Biol 2023; 6:715. [PMID: 37438411 DOI: 10.1038/s42003-023-05074-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 06/26/2023] [Indexed: 07/14/2023] Open
Abstract
The nucleus plays a central role in several key cellular processes, including chromosome organisation, DNA replication and gene transcription. Recent work suggests an association between nuclear mechanics and cell-cycle progression, but many aspects of this connection remain unexplored. Here, by monitoring nuclear shape fluctuations at different cell cycle stages, we uncover increasing inward fluctuations in late G2 and in early prophase, which are initially transient, but develop into instabilities when approaching the nuclear-envelope breakdown. We demonstrate that such deformations correlate with chromatin condensation by perturbing both the chromatin and the cytoskeletal structures. We propose that the contrasting forces between an extensile stress and centripetal pulling from chromatin condensation could mechanically link chromosome condensation with nuclear-envelope breakdown, two main nuclear processes occurring during mitosis.
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Affiliation(s)
- Viola Introini
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, UK
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus Keith Peters Building, Hills Rd, Cambridge, CB2 0XY, UK
| | - Gururaj Rao Kidiyoor
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Giancarlo Porcella
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy
| | - Pietro Cicuta
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Marco Cosentino Lagomarsino
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, Milan, 20139, Italy.
- Dipartimento di Fisica, Università degli Studi di Milano and I.N.F.N., Via Celoria 16, Milan, 20133, Italy.
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26
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Kadam S, Kumari K, Manivannan V, Dutta S, Mitra MK, Padinhateeri R. Predicting scale-dependent chromatin polymer properties from systematic coarse-graining. Nat Commun 2023; 14:4108. [PMID: 37433821 PMCID: PMC10336007 DOI: 10.1038/s41467-023-39907-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 06/30/2023] [Indexed: 07/13/2023] Open
Abstract
Simulating chromatin is crucial for predicting genome organization and dynamics. Although coarse-grained bead-spring polymer models are commonly used to describe chromatin, the relevant bead dimensions, elastic properties, and the nature of inter-bead potentials are unknown. Using nucleosome-resolution contact probability (Micro-C) data, we systematically coarse-grain chromatin and predict quantities essential for polymer representation of chromatin. We compute size distributions of chromatin beads for different coarse-graining scales, quantify fluctuations and distributions of bond lengths between neighboring regions, and derive effective spring constant values. Unlike the prevalent notion, our findings argue that coarse-grained chromatin beads must be considered as soft particles that can overlap, and we derive an effective inter-bead soft potential and quantify an overlap parameter. We also compute angle distributions giving insights into intrinsic folding and local bendability of chromatin. While the nucleosome-linker DNA bond angle naturally emerges from our work, we show two populations of local structural states. The bead sizes, bond lengths, and bond angles show different mean behavior at Topologically Associating Domain (TAD) boundaries and TAD interiors. We integrate our findings into a coarse-grained polymer model and provide quantitative estimates of all model parameters, which can serve as a foundational basis for all future coarse-grained chromatin simulations.
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Affiliation(s)
- Sangram Kadam
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
| | - Kiran Kumari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Vinoth Manivannan
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Shuvadip Dutta
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Mithun K Mitra
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Ranjith Padinhateeri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400076, India.
- Sunita Sanghi Centre of Aging and Neurodegenerative Diseases, Indian Institute of Technology Bombay, Mumbai, 400076, India.
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27
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Schibler AC, Jevtic P, Pegoraro G, Levy DL, Misteli T. Identification of epigenetic modulators as determinants of nuclear size and shape. eLife 2023; 12:e80653. [PMID: 37219077 PMCID: PMC10259489 DOI: 10.7554/elife.80653] [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: 05/29/2022] [Accepted: 05/04/2023] [Indexed: 05/24/2023] Open
Abstract
The shape and size of the human cell nucleus is highly variable among cell types and tissues. Changes in nuclear morphology are associated with disease, including cancer, as well as with premature and normal aging. Despite the very fundamental nature of nuclear morphology, the cellular factors that determine nuclear shape and size are not well understood. To identify regulators of nuclear architecture in a systematic and unbiased fashion, we performed a high-throughput imaging-based siRNA screen targeting 867 nuclear proteins including chromatin-associated proteins, epigenetic regulators, and nuclear envelope components. Using multiple morphometric parameters, and eliminating cell cycle effectors, we identified a set of novel determinants of nuclear size and shape. Interestingly, most identified factors altered nuclear morphology without affecting the levels of lamin proteins, which are known prominent regulators of nuclear shape. In contrast, a major group of nuclear shape regulators were modifiers of repressive heterochromatin. Biochemical and molecular analysis uncovered a direct physical interaction of histone H3 with lamin A mediated via combinatorial histone modifications. Furthermore, disease-causing lamin A mutations that result in disruption of nuclear shape inhibited lamin A-histone H3 interactions. Oncogenic histone H3.3 mutants defective for H3K27 methylation resulted in nuclear morphology abnormalities. Altogether, our results represent a systematic exploration of cellular factors involved in determining nuclear morphology and they identify the interaction of lamin A with histone H3 as an important contributor to nuclear morphology in human cells.
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Affiliation(s)
| | - Predrag Jevtic
- Department of Molecular Biology, University of WyomingLaramieUnited States
| | - Gianluca Pegoraro
- High Throughput Imaging Facility (HiTIF), National Cancer Institute, NIHBethesdaUnited States
| | - Daniel L Levy
- Department of Molecular Biology, University of WyomingLaramieUnited States
| | - Tom Misteli
- National Cancer InstituteBethesdaUnited States
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28
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Dror E, Fagnocchi L, Wegert V, Apostle S, Grimaldi B, Gruber T, Panzeri I, Heyne S, Höffler KD, Kreiner V, Ching R, Tsai-Hsiu Lu T, Semwal A, Johnson B, Senapati P, Lempradl A, Schones D, Imhof A, Shen H, Pospisilik JA. Epigenetic dosage identifies two major and functionally distinct β cell subtypes. Cell Metab 2023; 35:821-836.e7. [PMID: 36948185 PMCID: PMC10160009 DOI: 10.1016/j.cmet.2023.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 01/17/2023] [Accepted: 03/08/2023] [Indexed: 03/24/2023]
Abstract
The mechanisms that specify and stabilize cell subtypes remain poorly understood. Here, we identify two major subtypes of pancreatic β cells based on histone mark heterogeneity (βHI and βLO). βHI cells exhibit ∼4-fold higher levels of H3K27me3, distinct chromatin organization and compaction, and a specific transcriptional pattern. βHI and βLO cells also differ in size, morphology, cytosolic and nuclear ultrastructure, epigenomes, cell surface marker expression, and function, and can be FACS separated into CD24+ and CD24- fractions. Functionally, βHI cells have increased mitochondrial mass, activity, and insulin secretion in vivo and ex vivo. Partial loss of function indicates that H3K27me3 dosage regulates βHI/βLO ratio in vivo, suggesting that control of β cell subtype identity and ratio is at least partially uncoupled. Both subtypes are conserved in humans, with βHI cells enriched in humans with type 2 diabetes. Thus, epigenetic dosage is a novel regulator of cell subtype specification and identifies two functionally distinct β cell subtypes.
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Affiliation(s)
- Erez Dror
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany.
| | - Luca Fagnocchi
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Vanessa Wegert
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Stefanos Apostle
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Brooke Grimaldi
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Tim Gruber
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Ilaria Panzeri
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Steffen Heyne
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Kira Daniela Höffler
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Victor Kreiner
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Reagan Ching
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Tess Tsai-Hsiu Lu
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany
| | - Ayush Semwal
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Ben Johnson
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Parijat Senapati
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Adelheid Lempradl
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - Dustin Schones
- Department of Diabetes Complications and Metabolism, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA
| | - Axel Imhof
- Biomedical Center Munich, Ludwig Maximilian University of Munich, 82152 Planegg-Martinsried, Germany
| | - Hui Shen
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA
| | - John Andrew Pospisilik
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg 79108, Germany; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49503, USA.
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29
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Amin A, Kadam S, Mieczkowski J, Ahmed I, Bhat YA, Shah F, Tolstorukov MY, Kingston RE, Padinhateeri R, Wani AH. Disruption of polyhomeotic polymerization decreases nucleosome occupancy and alters genome accessibility. Life Sci Alliance 2023; 6:e202201768. [PMID: 36849253 PMCID: PMC9973501 DOI: 10.26508/lsa.202201768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/16/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023] Open
Abstract
Chromatin attains its three-dimensional (3D) conformation by establishing contacts between different noncontiguous regions. Sterile Alpha Motif (SAM)-mediated polymerization of the polyhomeotic (PH) protein regulates subnuclear clustering of Polycomb Repressive Complex 1 (PRC1) and chromatin topology. The mutations that perturb the ability of the PH to polymerize, disrupt long-range chromatin contacts, alter Hox gene expression, and lead to developmental defects. To understand the underlying mechanism, we combined the experiments and theory to investigate the effect of this SAM domain mutation on nucleosome occupancy and accessibility on a genome wide scale. Our data show that disruption of PH polymerization because of SAM domain mutation decreases nucleosome occupancy and alters accessibility. Polymer simulations investigating the interplay between distant chromatin contacts and nucleosome occupancy, both of which are regulated by PH polymerization, suggest that nucleosome density increases when contacts between different regions of chromatin are established. Taken together, it appears that SAM domain-mediated PH polymerization biomechanically regulates the organization of chromatin at multiple scales from nucleosomes to chromosomes and we suggest that higher order organization can have a top-down causation effect on nucleosome occupancy.
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Affiliation(s)
- Adfar Amin
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Sangram Kadam
- Department of Biosciences and Bioengineering, IIT, Bombay, India
| | - Jakub Mieczkowski
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Ikhlak Ahmed
- CIRI, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Younus A Bhat
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | - Fouziya Shah
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
| | | | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | | | - Ajazul H Wani
- Department of Biotechnology, School of Biological Sciences, University of Kashmir, Srinagar, India
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30
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Chen P, Mishra S, Levy DL. Nuclear growth and import can be uncoupled. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537556. [PMID: 37131802 PMCID: PMC10153267 DOI: 10.1101/2023.04.19.537556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while nuclear growth depends on nuclear import, nuclear growth and import can be uncoupled. Nuclei containing fragmented DNA grew slowly despite exhibiting normal import rates, suggesting nuclear import itself is insufficient to drive nuclear growth. Nuclei containing more DNA grew larger but imported more slowly. Altering chromatin modifications caused nuclei to grow less while still importing to the same extent or to grow larger without increasing nuclear import. Increasing heterochromatin in vivo in sea urchin embryos increased nuclear growth but not import. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, live imaging showed that nuclear growth preferentially occurred at sites of high chromatin density and lamin addition, whereas small nuclei lacking DNA exhibited less lamin incorporation. Our hypothesized model is that lamin incorporation and nuclear growth are driven by chromatin mechanical properties, which depend on and can be tuned by nuclear import.
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Affiliation(s)
- Pan Chen
- Department of Biochemistry and Molecular Biology and Zhejiang Key Laboratory of Pathophysiology, School of Basic Medical Sciences, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
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31
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Chen P, Levy DL. Regulation of organelle size and organization during development. Semin Cell Dev Biol 2023; 133:53-64. [PMID: 35148938 PMCID: PMC9357868 DOI: 10.1016/j.semcdb.2022.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/20/2022] [Accepted: 02/01/2022] [Indexed: 12/11/2022]
Abstract
During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.
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Affiliation(s)
- Pan Chen
- Institute of Biochemistry and Molecular Biology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
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32
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Chiu K, Berrada Y, Eskndir N, Song D, Fong C, Naughton S, Chen T, Moy S, Gyurmey S, James L, Ezeiruaku C, Capistran C, Lowey D, Diwanji V, Peterson S, Parakh H, Burgess AR, Probert C, Zhu A, Anderson B, Levi N, Gerlitz G, Packard MC, Dorfman KA, Bahiru MS, Stephens AD. CTCF is essential for proper mitotic spindle structure and anaphase segregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.09.523293. [PMID: 36712070 PMCID: PMC9881978 DOI: 10.1101/2023.01.09.523293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mitosis is an essential process in which the duplicated genome is segregated equally into two daughter cells. CTCF has been reported to be present in mitosis but its importance for mitotic fidelity remains to be determined. To evaluate the importance of CTCF in mitosis, we tracked mitotic behaviors in wild type and two different CTCF CRISPR-based genetic knockdowns. We find that knockdown of CTCF results in prolonged mitoses and failed anaphase segregation via time lapse imaging of SiR-DNA. CTCF knockdown did not alter cell cycling or the mitotic checkpoint, which was activated upon nocodazole treatment. Immunofluorescence imaging of the mitotic spindle in CTCF knockdowns revealed disorganization via tri/tetrapolar spindles and chromosomes behind the spindle pole. Imaging of interphase nuclei showed that nuclear size increased drastically, consistent with failure to divide the duplicated genome in anaphase. Population measurements of nuclear shape in CTCF knockdowns do not display decreased circularity or increased nuclear blebbing relative to wild type. However, failed mitoses do display abnormal nuclear morphologies relative to successful mitoses, suggesting population images do not capture individual behaviors. Thus, CTCF is important for both proper metaphase organization and anaphase segregation which impacts the size and shape of the interphase nucleus.
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Affiliation(s)
- Katherine Chiu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Yasmin Berrada
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Nebiyat Eskndir
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Dasol Song
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Claire Fong
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarah Naughton
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Tina Chen
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Savanna Moy
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sarah Gyurmey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Liam James
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Chimere Ezeiruaku
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Caroline Capistran
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Daniel Lowey
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Vedang Diwanji
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Samantha Peterson
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Harshini Parakh
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Ayanna R. Burgess
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Cassandra Probert
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Annie Zhu
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Bryn Anderson
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Nehora Levi
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Ariel 40700, Israel
| | - Gabi Gerlitz
- Biology Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Ariel 40700, Israel
| | - Mary C. Packard
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | | | | | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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33
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Flick Jaecker F, Almeida JA, Krull CM, Pathak A. Nucleoli in epithelial cell collectives respond to tumorigenic, spatial, and mechanical cues. Mol Biol Cell 2022; 33:br19. [PMID: 35830599 PMCID: PMC9582805 DOI: 10.1091/mbc.e22-02-0070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cancer cells are known to have larger nucleoli, consistent with their higher transcriptional and translational demands. Meanwhile, on stiff extracellular matrix, normal epithelial cells can exhibit genomic and proteomic mechanoactivation toward tumorigenic transformations, such as epithelial-mesenchymal transition and enhanced migration. However, while nucleolar bodies regulate the protein synthesis required for mechanosensation, it remains unknown whether mechanical and spatial extracellular cues can in turn alter nucleoli. Here, we culture mammary epithelial cell sheets on matrices of varying stiffness and show that cancer cells have more nucleoli, with nucleoli occupying larger areas compared with normal cells. By contrast, within normal epithelial sheets, stiffer matrices and leader positioning of cells induce larger nucleolar areas and more nucleolar bodies over time. The observed leader-follower nucleolar differences stem from distinct rates of cell cycle progression. In the nucleoplasm, leader cells on stiffer matrices exhibit higher heterochromatin marker expression and DNA compaction around nucleolar bodies. Overall, our findings advance the emerging framework of cellular mechanobiology in which mechanical cues from the extracellular matrix transmit into the nucleoplasm to alter nucleolar composition, potentially resulting in mechanosensitive ribosomal biogenesis. Ultimately, this proposed mechanosensitivity of nucleoli and associated protein synthesis could have wide implications in disease, development, and regeneration.
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Affiliation(s)
| | - José A Almeida
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130
| | - Carly M Krull
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130
| | - Amit Pathak
- Department of Mechanical Engineering & Materials Science and.,Department of Biomedical Engineering, Washington University, St. Louis, MO 63130
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Currey ML, Kandula V, Biggs R, Marko JF, Stephens AD. A Versatile Micromanipulation Apparatus for Biophysical Assays of the Cell Nucleus. Cell Mol Bioeng 2022; 15:303-312. [PMID: 36119136 PMCID: PMC9474788 DOI: 10.1007/s12195-022-00734-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/08/2022] [Indexed: 12/02/2022] Open
Abstract
Intro Force measurements of the nucleus, the strongest organelle, have propelled the field of mechanobiology to understand the basic mechanical components of the nucleus and how these components properly support nuclear morphology and function. Micromanipulation force measurement provides separation of the relative roles of nuclear mechanical components chromatin and lamin A. Methods To provide access to this technique, we have developed a universal micromanipulation apparatus for inverted microscopes. We outline how to engineer and utilize this apparatus through dual micromanipulators, fashion and calibrate micropipettes, and flow systems to isolate a nucleus and provide force vs. extensions measurements. This force measurement approach provides the unique ability to measure the separate contributions of chromatin at short extensions and lamin A strain stiffening at long extensions. We then investigated the apparatus’ controllable and programmable micromanipulators through compression, isolation, and extension in conjunction with fluorescence to develop new assays for nuclear mechanobiology. Results Using this methodology, we provide the first rebuilding of the micromanipulation setup outside of its lab of origin and recapitulate many key findings including spring constant of the nucleus and strain stiffening across many cell types. Furthermore, we have developed new micromanipulation-based techniques to compress nuclei inducing nuclear deformation and/or rupture, track nuclear shape post-isolation, and fluorescence imaging during micromanipulation force measurements. Conclusion We provide the workflow to build and use a micromanipulation apparatus with any inverted microscope to perform nucleus isolation, force measurements, and various other biophysical techniques. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-022-00734-y.
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Affiliation(s)
| | - Viswajit Kandula
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
- Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Ronald Biggs
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
| | - John F. Marko
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, USA
| | - Andrew D. Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, USA
- Molecular and Cellular Biosciences, University of Massachusetts Amherst, Amherst, USA
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Jana A, Tran A, Gill A, Kiepas A, Kapania RK, Konstantopoulos K, Nain AS. Sculpting Rupture-Free Nuclear Shapes in Fibrous Environments. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2203011. [PMID: 35863910 PMCID: PMC9443471 DOI: 10.1002/advs.202203011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Indexed: 05/07/2023]
Abstract
Cytoskeleton-mediated force transmission regulates nucleus morphology. How nuclei shaping occurs in fibrous in vivo environments remains poorly understood. Here suspended nanofiber networks of precisely tunable (nm-µm) diameters are used to quantify nucleus plasticity in fibrous environments mimicking the natural extracellular matrix. Contrary to the apical cap over the nucleus in cells on 2-dimensional surfaces, the cytoskeleton of cells on fibers displays a uniform actin network caging the nucleus. The role of contractility-driven caging in sculpting nuclear shapes is investigated as cells spread on aligned single fibers, doublets, and multiple fibers of varying diameters. Cell contractility increases with fiber diameter due to increased focal adhesion clustering and density of actin stress fibers, which correlates with increased mechanosensitive transcription factor Yes-associated protein (YAP) translocation to the nucleus. Unexpectedly, large- and small-diameter fiber combinations lead to teardrop-shaped nuclei due to stress fiber anisotropy across the cell. As cells spread on fibers, diameter-dependent nuclear envelope invaginations that run the nucleus's length are formed at fiber contact sites. The sharpest invaginations enriched with heterochromatin clustering and sites of DNA repair are insufficient to trigger nucleus rupture. Overall, the authors quantitate the previously unknown sculpting and adaptability of nuclei to fibrous environments with pathophysiological implications.
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Affiliation(s)
- Aniket Jana
- Department of Mechanical EngineeringVirginia TechBlacksburgVA24061USA
| | - Avery Tran
- Department of Chemical and Biomolecular EngineeringJohns Hopkins UniversityBaltimoreMD21218USA
| | - Amritpal Gill
- Department of Mechanical EngineeringVirginia TechBlacksburgVA24061USA
| | - Alexander Kiepas
- Department of Chemical and Biomolecular EngineeringJohns Hopkins UniversityBaltimoreMD21218USA
| | - Rakesh K. Kapania
- Kevin T. Crofton Department of Aerospace EngineeringVirginia TechBlacksburgVA24061USA
| | | | - Amrinder S. Nain
- Department of Mechanical EngineeringVirginia TechBlacksburgVA24061USA
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Infante E, Etienne-Manneville S. Intermediate filaments: Integration of cell mechanical properties during migration. Front Cell Dev Biol 2022; 10:951816. [PMID: 35990612 PMCID: PMC9389290 DOI: 10.3389/fcell.2022.951816] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/07/2022] [Indexed: 11/22/2022] Open
Abstract
Cell migration is a vital and dynamic process required for the development of multicellular organisms and for immune system responses, tissue renewal and wound healing in adults. It also contributes to a variety of human diseases such as cancers, autoimmune diseases, chronic inflammation and fibrosis. The cytoskeleton, which includes actin microfilaments, microtubules, and intermediate filaments (IFs), is responsible for the maintenance of animal cell shape and structural integrity. Each cytoskeletal network contributes its unique properties to dynamic cell behaviour, such as cell polarization, membrane protrusion, cell adhesion and contraction. Hence, cell migration requires the dynamic orchestration of all cytoskeleton components. Among these, IFs have emerged as a molecular scaffold with unique mechanical features and a key player in the cell resilience to mechanical stresses during migration through complex 3D environment. Moreover, accumulating evidence illustrates the participation of IFs in signalling cascades and cytoskeletal crosstalk. Teaming up with actin and microtubules, IFs contribute to the active generation of forces required for cell adhesion and mesenchymal migration and invasion. Here we summarize and discuss how IFs integrate mechanical properties and signalling functions to control cell migration in a wide spectrum of physiological and pathological situations.
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Mishra S, Levy DL. Nuclear F-actin and Lamin A antagonistically modulate nuclear shape. J Cell Sci 2022; 135:275607. [PMID: 35665815 PMCID: PMC9377710 DOI: 10.1242/jcs.259692] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/28/2022] [Indexed: 12/25/2022] Open
Abstract
Nuclear shape influences cell migration, gene expression and cell cycle progression, and is altered in disease states like laminopathies and cancer. What factors and forces determine nuclear shape? We find that nuclei assembled in Xenopus egg extracts in the presence of dynamic F-actin exhibit a striking bilobed nuclear morphology with distinct membrane compositions in the two lobes and accumulation of F-actin at the inner nuclear envelope. The addition of Lamin A (encoded by lmna), which is absent from Xenopus eggs, results in rounder nuclei, suggesting that opposing nuclear F-actin and Lamin A forces contribute to the regulation of nuclear shape. Nuclear F-actin also promotes altered nuclear shape in Lamin A-knockdown HeLa cells and, in both systems, abnormal nuclear shape is driven by formins and not Arp2/3 or myosin. Although the underlying mechanisms might differ in Xenopus and HeLa cells, we propose that nuclear F-actin filaments nucleated by formins impart outward forces that lead to altered nuclear morphology unless Lamin A is present. Targeting nuclear actin dynamics might represent a novel approach to rescuing disease-associated defects in nuclear shape.
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Affiliation(s)
- Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA
| | - Daniel L. Levy
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA,Author for correspondence ()
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Peng M, Rayana NP, Dai J, Sugali CK, Baidouri H, Suresh A, Raghunathan VK, Mao W. Cross-linked actin networks (CLANs) affect stiffness and/or actin dynamics in transgenic transformed and primary human trabecular meshwork cells. Exp Eye Res 2022; 220:109097. [PMID: 35569518 PMCID: PMC11029344 DOI: 10.1016/j.exer.2022.109097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 01/14/2023]
Abstract
Cross-linked actin networks (CLANs) in trabecular meshwork (TM) cells may contribute to increased IOP by altering TM cell function and stiffness. However, there is a lack of direct evidence. Here, we developed transformed TM cells that form spontaneous fluorescently labelled CLANs. The stable cells were constructed by transducing transformed glaucomatous TM (GTM3) cells with the pLenti-LifeAct-EGFP-BlastR lentiviral vector and selection with blasticidin. The stiffness of the GTM3-LifeAct-GFP cells were studied using atomic force microscopy. Elastic moduli of CLANs in primary human TM cells treated with/without dexamethasone/TGFβ2 were also measured to validate findings in GTM3-LifeAct-GFP cells. Live-cell imaging was performed on GTM3-LifeAct-GFP cells treated with 1 μM latrunculin B or pHrodo bioparticles to determine actin stability and phagocytosis, respectively. The GTM3-LifeAct-GFP cells formed spontaneous CLANs without the induction of TGFβ2 or dexamethasone. The CLAN containing cells showed elevated cell stiffness, resistance to latrunculin B-induced actin depolymerization, as well as compromised phagocytosis, compared to the cells without CLANs. Primary human TM cells with dexamethasone or TGFβ2-induced CLANs were also stiffer and less phagocytic. The GTM3-LifeAct-GFP cells are a novel tool for studying the mechanobiology and pathology of CLANs in the TM. Initial characterization of these cells showed that CLANs contribute to at least some glaucomatous phenotypes of TM cells.
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Affiliation(s)
- Michael Peng
- Department of Ophthalmology, Eugene & Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Naga Pradeep Rayana
- Department of Ophthalmology, Eugene & Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jiannong Dai
- Department of Ophthalmology, Eugene & Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chenna Kesavulu Sugali
- Department of Ophthalmology, Eugene & Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Hasna Baidouri
- Department of Basic Sciences, College of Optometry, University of Houston, Houston, TX, USA
| | - Ayush Suresh
- Department of Basic Sciences, College of Optometry, University of Houston, Houston, TX, USA; St. John's School, Houston, TX, USA
| | - Vijay Krishna Raghunathan
- Department of Basic Sciences, College of Optometry, University of Houston, Houston, TX, USA; Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX, USA
| | - Weiming Mao
- Department of Ophthalmology, Eugene & Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Razin SV, Ulianov SV. Genome-Directed Cell Nucleus Assembly. BIOLOGY 2022; 11:biology11050708. [PMID: 35625436 PMCID: PMC9138775 DOI: 10.3390/biology11050708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Speckles and other nuclear bodies, the nucleolus and perinucleolar zone, transcription/replication factories and the lamina-associated compartment, serve as a structural basis for various genomic functions. In turn, genome activity and specific chromatin 3D organization directly impact the integrity of intranuclear assemblies, initiating/facilitating their formation and dictating their composition. Thus, the large-scale nucleus structure and genome activity mutually influence each other. The cell nucleus is frequently considered a compartment in which the genome is placed to protect it from external forces. Here, we discuss the evidence demonstrating that the cell nucleus should be considered, rather, as structure built around the folded genome. Decondensing chromosomes provide a scaffold for the assembly of the nuclear envelope after mitosis, whereas genome activity directs the assembly of various nuclear compartments, including nucleolus, speckles and transcription factories. Abstract The cell nucleus is frequently considered a cage in which the genome is placed to protect it from various external factors. Inside the nucleus, many functional compartments have been identified that are directly or indirectly involved in implementing genomic DNA’s genetic functions. For many years, it was assumed that these compartments are assembled on a proteinaceous scaffold (nuclear matrix), which provides a structural milieu for nuclear compartmentalization and genome folding while simultaneously offering some rigidity to the cell nucleus. The results of research in recent years have made it possible to consider the cell nucleus from a different angle. From the “box” in which the genome is placed, the nucleus has become a kind of mobile exoskeleton, which is formed around the packaged genome, under the influence of transcription and other processes directly related to the genome activity. In this review, we summarize the main arguments in favor of this point of view by analyzing the mechanisms that mediate cell nucleus assembly and support its resistance to mechanical stresses.
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Affiliation(s)
- Sergey V. Razin
- Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
- Correspondence: or
| | - Sergey V. Ulianov
- Institute of Gene Biology, Russian Academy of Sciences, 119334 Moscow, Russia;
- Faculty of Biology, M.V. Lomonosov Moscow State University, 119234 Moscow, Russia
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40
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A facile cell culture device for studying nuclear and mitochondrial response of endothelial cells to hydrostatic pressure. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.04.084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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41
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Zakharova VV, Magnitov MD, Del Maestro L, Ulianov SV, Glentis A, Uyanik B, Williart A, Karpukhina A, Demidov O, Joliot V, Vassetzky Y, Mège RM, Piel M, Razin S, Ait-Si-Ali S. SETDB1 fuels the lung cancer phenotype by modulating epigenome, 3D genome organization and chromatin mechanical properties. Nucleic Acids Res 2022; 50:4389-4413. [PMID: 35474385 PMCID: PMC9071401 DOI: 10.1093/nar/gkac234] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/15/2022] [Accepted: 04/21/2022] [Indexed: 12/24/2022] Open
Abstract
Imbalance in the finely orchestrated system of chromatin-modifying enzymes is a hallmark of many pathologies such as cancers, since causing the affection of the epigenome and transcriptional reprogramming. Here, we demonstrate that a loss-of-function mutation (LOF) of the major histone lysine methyltransferase SETDB1 possessing oncogenic activity in lung cancer cells leads to broad changes in the overall architecture and mechanical properties of the nucleus through genome-wide redistribution of heterochromatin, which perturbs chromatin spatial compartmentalization. Together with the enforced activation of the epithelial expression program, cytoskeleton remodeling, reduced proliferation rate and restricted cellular migration, this leads to the reversed oncogenic potential of lung adenocarcinoma cells. These results emphasize an essential role of chromatin architecture in the determination of oncogenic programs and illustrate a relationship between gene expression, epigenome, 3D genome and nuclear mechanics.
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Affiliation(s)
- Vlada V Zakharova
- Epigenetics and Cell Fate (EDC) department, UMR7216, CNRS, Université Paris Cité, F-75013 Paris, France
| | - Mikhail D Magnitov
- Institute of Gene Biology, Russian Academy of Science, Moscow 119334, Russia
| | - Laurence Del Maestro
- Epigenetics and Cell Fate (EDC) department, UMR7216, CNRS, Université Paris Cité, F-75013 Paris, France
| | - Sergey V Ulianov
- Institute of Gene Biology, Russian Academy of Science, Moscow 119334, Russia,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alexandros Glentis
- Institute Jacques Monod, CNRS, Université Paris Cité, F-75013 Paris, France
| | - Burhan Uyanik
- INSERM UMR1231, LipSTIC, University of Burgundy Franche-Comté F-21000, Dijon, France
| | - Alice Williart
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, 75248 Paris, France
| | - Anna Karpukhina
- UMR9018, CNRS, Université Paris-Sud Paris-Saclay, Institut Gustave Roussy; 94805 Villejuif, France,Koltzov Institute of Developmental Biology, 119334 Moscow, Russia
| | - Oleg Demidov
- INSERM UMR1231, LipSTIC, University of Burgundy Franche-Comté F-21000, Dijon, France,Institute of Cytology, RAS, 194064 St. Petersburg, Russia,NTU Sirius, 354340 Sochi, Russia
| | - Veronique Joliot
- Epigenetics and Cell Fate (EDC) department, UMR7216, CNRS, Université Paris Cité, F-75013 Paris, France
| | - Yegor S Vassetzky
- UMR9018, CNRS, Université Paris-Sud Paris-Saclay, Institut Gustave Roussy; 94805 Villejuif, France,Koltzov Institute of Developmental Biology, 119334 Moscow, Russia
| | - René-Marc Mège
- Institute Jacques Monod, CNRS, Université Paris Cité, F-75013 Paris, France
| | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, 75248 Paris, France
| | - Sergey V Razin
- Correspondence may also be addressed to Sergey V. Razin. Tel: +7 499 135 3092;
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Yan Y, Shi M, Fannin R, Yu L, Liu J, Castro L, Dixon D. Prolonged Cadmium Exposure Alters Migration Dynamics and Increases Heterogeneity of Human Uterine Fibroid Cells—Insights from Time Lapse Analysis. Biomedicines 2022; 10:biomedicines10040917. [PMID: 35453667 PMCID: PMC9031958 DOI: 10.3390/biomedicines10040917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 04/03/2022] [Accepted: 04/05/2022] [Indexed: 11/16/2022] Open
Abstract
Cadmium (Cd) is one of the most prevalent environmental heavy metal contaminants and is considered an endocrine disruptor and carcinogen. In women with uterine fibroids, there is a correlation between blood Cd levels and fibroid tumor size. In this study, fibroid cells were exposed to 10 µM CdCl2 for 6 months and a fast-growing Cd-Resistant Leiomyoma culture, termed CR-LM6, was recovered. To characterize the morphological and mechanodynamic features of uterine fibroid cells associated with prolonged Cd exposure, we conducted time lapse imaging using a Zeiss confocal microscope and analyzed data by Imaris and RStudio. Our experiments recorded more than 64,000 trackable nuclear surface objects, with each having multiple parameters such as nuclear size and shape, speed, location, orientation, track length, and track straightness. Quantitative analysis revealed that prolonged Cd exposure significantly altered cell migration behavior, such as increased track length and reduced track straightness. Cd exposure also significantly increased the heterogeneity in nuclear size. Additionally, Cd significantly increased the median and variance of instantaneous speed, indicating that Cd exposure results in higher speed and greater variation in motility. Profiling of mRNA by NanoString analysis and Ingenuity Pathway Analysis (IPA) strongly suggested that the direction of gene expression changes due to Cd exposure enhanced cell movement and invasion. The altered expression of extracellular matrix (ECM) genes such as collagens, matrix metallopeptidases (MMPs), secreted phosphoprotein 1 (SPP1), which are important for migration contact guidance, may be responsible for the greater heterogeneity. The significantly increased heterogeneity of nuclear size, speed, and altered migration patterns may be a prerequisite for fibroid cells to attain characteristics favorable for cancer progression, invasion, and metastasis.
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Affiliation(s)
- Yitang Yan
- Molecular Pathogenesis Group, Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA; (Y.Y.); (L.Y.); (J.L.); (L.C.)
| | - Min Shi
- Biostatistics & Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA;
| | - Rick Fannin
- Molecular Genomics Core Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA;
| | - Linda Yu
- Molecular Pathogenesis Group, Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA; (Y.Y.); (L.Y.); (J.L.); (L.C.)
| | - Jingli Liu
- Molecular Pathogenesis Group, Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA; (Y.Y.); (L.Y.); (J.L.); (L.C.)
| | - Lysandra Castro
- Molecular Pathogenesis Group, Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA; (Y.Y.); (L.Y.); (J.L.); (L.C.)
| | - Darlene Dixon
- Molecular Pathogenesis Group, Mechanistic Toxicology Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Durham, NC 27709, USA; (Y.Y.); (L.Y.); (J.L.); (L.C.)
- Correspondence: ; Tel.: +1-984-287-3848
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Reilly A, Philip Creamer J, Stewart S, Stolla MC, Wang Y, Du J, Wellington R, Busch S, Estey EH, Becker PS, Fang M, Keel SB, Abkowitz JL, Soma LA, Ma J, Duan Z, Doulatov S. Lamin B1 deletion in myeloid neoplasms causes nuclear anomaly and altered hematopoietic stem cell function. Cell Stem Cell 2022; 29:577-592.e8. [PMID: 35278369 PMCID: PMC9018112 DOI: 10.1016/j.stem.2022.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 01/05/2022] [Accepted: 02/15/2022] [Indexed: 11/19/2022]
Abstract
Abnormal nuclear morphology is a hallmark of malignant cells widely used in cancer diagnosis. Pelger-Huët anomaly (PHA) is a common abnormality of neutrophil nuclear morphology of unknown molecular etiology in myeloid neoplasms (MNs). We show that loss of nuclear lamin B1 (LMNB1) encoded on chromosome 5q, which is frequently deleted in MNs, induces defects in nuclear morphology and human hematopoietic stem cell (HSC) function associated with malignancy. LMNB1 deficiency alters genome organization inducing in vitro and in vivo expansion of HSCs, myeloid-biased differentiation with impaired lymphoid commitment, and genome instability due to defective DNA damage repair. Nuclear dysmorphology of neutrophils in patients with MNs is associated with 5q deletions spanning the LMNB1 locus, and lamin B1 loss is both necessary and sufficient to cause PHA in normal and 5q-deleted neutrophils. LMNB1 loss thus causes acquired PHA and links abnormal nuclear morphology with HSCs and progenitor cell fate determination via genome organization.
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Affiliation(s)
- Andreea Reilly
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - J Philip Creamer
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sintra Stewart
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Massiel C Stolla
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Yuchuan Wang
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jing Du
- Division of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Rachel Wellington
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Stephanie Busch
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Elihu H Estey
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Pamela S Becker
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Division of Hematology/Oncology, Chao Family Comprehensive Cancer Center, University of California Irvine, Irvine, CA 92617, USA; Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Min Fang
- Department of Clinical Transplant Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Siobán B Keel
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Janis L Abkowitz
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Lorinda A Soma
- Division of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Jian Ma
- Computational Biology Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Zhijun Duan
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sergei Doulatov
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA; Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98195, USA.
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Huguet F, Gokhan E, Foster HA, Amin HA, Vagnarelli P. Repo-Man/protein phosphatase 1 SUMOylation mediates binding to lamin A and serine 22 dephosphorylation. Open Biol 2022; 12:220017. [PMID: 35414260 PMCID: PMC9006038 DOI: 10.1098/rsob.220017] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/14/2022] [Indexed: 01/09/2023] Open
Abstract
Lamin A phosphorylation/de-phosphorylation is an important process during cells division as it allows for nuclear envelope (NE) disassembly at mitotic entry and its re-assembly during mitotic exit. Several kinases have been identified as responsible for these phosphorylations, but no protein phosphatase has been implicated in their reversal. One of the mitotic phosphosites in lamin A responsible for its dynamic behaviour is serine 22 (S22) which is de-phosphorylated during mitotic exit. Recent evidence has also linked the nuclear pool of lamin A S22ph in interphase to gene expression regulation. Previous work suggested that the phosphatase responsible for lamin A S22 de-phosphorylation is chromatin bound and interacts with lamin A via SUMO-SIM motives. We have previously reported that Repo-Man/protein phosphatase 1 (PP1) is a chromatin-associated phosphatase that regulates NE reformation. Here we propose that Repo-Man/PP1 phosphatase mediates lamin A S22 de-phosphorylation. We indeed show that depletion of Repo-Man leads to NE defects, causes hyperphosphorylation of lamin A S22 that can be rescued by a wild-type but not a SUMOylation-deficient mutant. Lamin A and Repo-Man interact in vivo and in vitro, and the interaction is mediated by SUMOylation. Moreover, the localization of Repo-Man/PP1 to the chromatin is essential for lamin A S22 de-phosphorylation.
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Affiliation(s)
- Florentin Huguet
- College of Medicine, Health and Life Science, Brunel University London, Centre for Genomic Engineering and Maintenance (CenGem), London UB8 3PH, UK
| | - Ezgi Gokhan
- College of Medicine, Health and Life Science, Brunel University London, Centre for Genomic Engineering and Maintenance (CenGem), London UB8 3PH, UK
| | - Helen A. Foster
- Biosciences, Department of Clinical, Pharmaceutical and Biological Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfiled, UK
| | - Hasnat A. Amin
- College of Medicine, Health and Life Science, Brunel University London, Centre for Genomic Engineering and Maintenance (CenGem), London UB8 3PH, UK
| | - Paola Vagnarelli
- College of Medicine, Health and Life Science, Brunel University London, Centre for Genomic Engineering and Maintenance (CenGem), London UB8 3PH, UK
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45
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Scalvini B, Schiessel H, Golovnev A, Mashaghi A. Circuit topology analysis of cellular genome reveals signature motifs, conformational heterogeneity, and scaling. iScience 2022; 25:103866. [PMID: 35243229 PMCID: PMC8861635 DOI: 10.1016/j.isci.2022.103866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 12/14/2021] [Accepted: 01/31/2022] [Indexed: 11/30/2022] Open
Abstract
Reciprocal regulation of genome topology and function is a fundamental and enduring puzzle in biology. The wealth of data provided by Hi-C libraries offers the opportunity to unravel this relationship. However, there is a need for a comprehensive theoretical framework in order to extract topological information for genome characterization and comparison. Here, we develop a toolbox for topological analysis based on Circuit Topology, allowing for the quantification of inter- and intracellular genomic heterogeneity, at various levels of fold complexity: pairwise contact arrangement, higher-order contact arrangement, and topological fractal dimension. Single-cell Hi-C data were analyzed and characterized based on topological content, revealing not only a strong multiscale heterogeneity but also highly conserved features such as a characteristic topological length scale and topological signature motifs in the genome. We propose that these motifs inform on the topological state of the nucleus and indicate the presence of active loop extrusion. Circuit topology quantifies heterogeneity in genomic arrangement Scale analysis reveals a characteristic length scale of 10 Mb in genome topology We identify highly conserved topological structures related to loop extrusion We suggest a topological model of chromatin arrangement for loop extrusion, the L-loop
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Affiliation(s)
- Barbara Scalvini
- Medical Systems Biophysics and Bioengineering, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
| | - Helmut Schiessel
- Cluster of Excellence Physics of Life, Technical University of Dresden, 01062 Dresden, Germany
| | - Anatoly Golovnev
- Medical Systems Biophysics and Bioengineering, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
| | - Alireza Mashaghi
- Medical Systems Biophysics and Bioengineering, Leiden Academic Centre for Drug Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
- Centre for Interdisciplinary Genome Research, Faculty of Science, Leiden University, Einsteinweg 55, 2333CC Leiden, the Netherlands
- Corresponding author
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46
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Wei YL, Fan XJ, Diao YY, She ZY, Wang XR. Kinesin-14 KIFC1 modulates spindle assembly and chromosome segregation in mouse spermatocytes. Exp Cell Res 2022; 414:113095. [DOI: 10.1016/j.yexcr.2022.113095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 03/02/2022] [Accepted: 03/03/2022] [Indexed: 11/04/2022]
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47
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Mammel AE, Hatch EM. Genome instability from nuclear catastrophe and DNA damage. Semin Cell Dev Biol 2022; 123:131-139. [PMID: 33839019 PMCID: PMC8494860 DOI: 10.1016/j.semcdb.2021.03.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/29/2021] [Indexed: 11/28/2022]
Abstract
The nuclear envelope compartmentalizes the eukaryotic genome, provides mechanical resistance, and regulates access to the chromatin. However, recent studies have identified several conditions where the nuclear membrane ruptures during interphase, breaking down this compartmentalization leading to DNA damage, chromothripsis, and kataegis. This review discusses three major circumstances that promote nuclear membrane rupture, nuclear deformation, chromatin bridges, and micronucleation, and how each of these nuclear catastrophes results in DNA damage. In addition, we highlight recent studies that demonstrate a single chromosome missegregation can initiate a cascade of events that lead to accumulating damage and even multiple rounds of chromothripsis.
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Affiliation(s)
- Anna E. Mammel
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
| | - Emily M. Hatch
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA,Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
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48
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Vahabikashi A, Adam SA, Medalia O, Goldman RD. Nuclear lamins: Structure and function in mechanobiology. APL Bioeng 2022; 6:011503. [PMID: 35146235 PMCID: PMC8810204 DOI: 10.1063/5.0082656] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/11/2022] [Indexed: 12/11/2022] Open
Abstract
Nuclear lamins are type V intermediate filament proteins that polymerize into complex filamentous meshworks at the nuclear periphery and in less structured forms throughout the nucleoplasm. Lamins interact with a wide range of nuclear proteins and are involved in numerous nuclear and cellular functions. Within the nucleus, they play roles in chromatin organization and gene regulation, nuclear shape, size, and mechanics, and the organization and anchorage of nuclear pore complexes. At the whole cell level, they are involved in the organization of the cytoskeleton, cell motility, and mechanotransduction. The expression of different lamin isoforms has been associated with developmental progression, differentiation, and tissue-specific functions. Mutations in lamins and their binding proteins result in over 15 distinct human diseases, referred to as laminopathies. The laminopathies include muscular (e.g., Emery-Dreifuss muscular dystrophy and dilated cardiomyopathy), neurological (e.g., microcephaly), and metabolic (e.g., familial partial lipodystrophy) disorders as well as premature aging diseases (e.g., Hutchinson-Gilford Progeria and Werner syndromes). How lamins contribute to the etiology of laminopathies is still unknown. In this review article, we summarize major recent findings on the structure, organization, and multiple functions of lamins in nuclear and more global cellular processes.
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Affiliation(s)
- Amir Vahabikashi
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Stephen A. Adam
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Robert D. Goldman
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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49
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Brändle F, Frühbauer B, Jagannathan M. Principles and functions of pericentromeric satellite DNA clustering into chromocenters. Semin Cell Dev Biol 2022; 128:26-39. [PMID: 35144860 DOI: 10.1016/j.semcdb.2022.02.005] [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] [Received: 01/03/2022] [Revised: 02/03/2022] [Accepted: 02/03/2022] [Indexed: 12/29/2022]
Abstract
Simple non-coding tandem repeats known as satellite DNA are observed widely across eukaryotes. These repeats occupy vast regions at the centromere and pericentromere of chromosomes but their contribution to cellular function has remained incompletely understood. Here, we review the literature on pericentromeric satellite DNA and discuss its organization and functions across eukaryotic species. We specifically focus on chromocenters, DNA-dense nuclear foci that contain clustered pericentromeric satellite DNA repeats from multiple chromosomes. We first discuss chromocenter formation and the roles that epigenetic modifications, satellite DNA transcripts and sequence-specific satellite DNA-binding play in this process. We then review the newly emerging functions of chromocenters in genome encapsulation, the maintenance of cell fate and speciation. We specifically highlight how the rapid divergence of satellite DNA repeats impacts reproductive isolation between closely related species. Together, we underline the importance of this so-called 'junk DNA' in fundamental biological processes.
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Affiliation(s)
- Franziska Brändle
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Benjamin Frühbauer
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Madhav Jagannathan
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland.
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50
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Hammonds EF, Harwig MC, Paintsil EA, Tillison EA, Hill RB, Morrison EA. Histone H3 and H4 tails play an important role in nucleosome phase separation. Biophys Chem 2022; 283:106767. [PMID: 35158124 PMCID: PMC8963862 DOI: 10.1016/j.bpc.2022.106767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 11/28/2022]
Abstract
Chromatin organization and its dynamic regulation are crucial in governing the temporal and spatial accessibility of DNA for proper gene expression. Disordered chains of nucleosomes comprise the basis of eukaryotic chromatin, forming higher-level organization across a range of length scales. Models of chromatin organization involving phase separation driven by chromatin-associating proteins have been proposed. More recently, evidence has emerged that nucleosome arrays can phase separate in the absence of other protein factors, yet questions remain regarding the molecular basis of chromatin phase separation that governs this dynamic nuclear organization. Here, we break chromatin down into its most basic subunit, the nucleosome core particle, and investigate phase separation using turbidity assays in conjunction with differential interference contrast microscopy. We show that, at physiologically-relevant concentrations, this fundamental subunit of chromatin undergoes phase separation. Individually removing the H3 and H4 tails abrogates phase separation under the same conditions. Taking a reductionist approach to investigate H3 and H4 tail peptide interactions in-trans with DNA and nucleosome core particles supports the direct involvement of these tails in chromatin phase separation. These results provide insight into fundamental mechanisms underlying phase separation of chromatin, which starts at the level of the nucleosome core particle, and support that long-range inter-nucleosomal interactions are sufficient to drive phase separation at nuclear concentrations. Additionally, our data have implications for understanding crosstalk between histone tails and provide a lens through which to interpret the effect of histone post-translational modifications and sequence variants. STATEMENT OF SIGNIFICANCE: Emerging models propose that chromatin organization is based in phase separation, however, mechanisms that drive this dynamic nuclear organization are only beginning to be understood. Previous focus has been on phase separation driven by chromatin-associating proteins, but this has recently shifted to recognize a direct role of chromatin in phase separation. Here, we take a fundamental approach in understanding chromatin phase separation and present new findings that the basic subunit of chromatin, the nucleosome core particle, undergoes phase separation under physiological concentrations of nucleosome and monovalent salt. Furthermore, the histone H3 and H4 tails are involved in phase separation in a manner independent of histone-associating proteins. These data suggest that H3 and H4 tail epigenetic factors may modulate chromatin phase separation.
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Affiliation(s)
- Erin F Hammonds
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America
| | - Megan Cleland Harwig
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America
| | - Emeleeta A Paintsil
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America
| | - Emma A Tillison
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America; Medical Scientist Training Program, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America
| | - R Blake Hill
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America
| | - Emma A Morrison
- Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, United States of America.
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