1
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Kumar P, Gholamalamdari O, Zhang Y, Zhang L, Vertii A, van Schaik T, Peric-Hupkes D, Sasaki T, Gilbert DM, van Steensel B, Ma J, Kaufman PD, Belmont AS. Nucleolus and centromere Tyramide Signal Amplification-Seq reveals variable localization of heterochromatin in different cell types. Commun Biol 2024; 7:1135. [PMID: 39271748 DOI: 10.1038/s42003-024-06838-7] [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: 11/16/2023] [Accepted: 09/04/2024] [Indexed: 09/15/2024] Open
Abstract
Genome differential positioning within interphase nuclei remains poorly explored. We extended and validated Tyramide Signal Amplification (TSA)-seq to map genomic regions near nucleoli and pericentric heterochromatin in four human cell lines. Our study confirmed that smaller chromosomes localize closer to nucleoli but further deconvolved this by revealing a preference for chromosome arms below 36-46 Mbp in length. We identified two lamina associated domain subsets through their differential nuclear lamina versus nucleolar positioning in different cell lines which showed distinctive patterns of DNA replication timing and gene expression across all cell lines. Unexpectedly, active, nuclear speckle-associated genomic regions were found near typically repressive nuclear compartments, which is attributable to the close proximity of nuclear speckles and nucleoli in some cell types, and association of centromeres with nuclear speckles in human embryonic stem cells (hESCs). Our study points to a more complex and variable nuclear genome organization than suggested by current models, as revealed by our TSA-seq methodology.
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Affiliation(s)
- Pradeep Kumar
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Omid Gholamalamdari
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yang Zhang
- Ray and Stephanie Lane Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Liguo Zhang
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Anastassiia Vertii
- Department of Molecular, Cellular and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Tom van Schaik
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Daan Peric-Hupkes
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Takayo Sasaki
- San Diego Biomedical Research Institute, San Diego, CA, USA
| | | | - Bas van Steensel
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Jian Ma
- Ray and Stephanie Lane Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Paul D Kaufman
- Department of Molecular, Cellular and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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2
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Gholamalamdari O, van Schaik T, Wang Y, Kumar P, Zhang L, Zhang Y, Gonzalez GAH, Vouzas AE, Zhao PA, Gilbert DM, Ma J, van Steensel B, Belmont AS. Beyond A and B Compartments: how major nuclear locales define nuclear genome organization and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.23.590809. [PMID: 38712201 PMCID: PMC11071382 DOI: 10.1101/2024.04.23.590809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Models of nuclear genome organization often propose a binary division into active versus inactive compartments, yet they overlook nuclear bodies. Here we integrated analysis of sequencing and image-based data to compare genome organization in four human cell types relative to three different nuclear locales: the nuclear lamina, nuclear speckles, and nucleoli. Whereas gene expression correlates mostly with nuclear speckle proximity, DNA replication timing correlates with proximity to multiple nuclear locales. Speckle attachment regions emerge as DNA replication initiation zones whose replication timing and gene composition vary with their attachment frequency. Most facultative LADs retain a partially repressed state as iLADs, despite their positioning in the nuclear interior. Knock out of two lamina proteins, Lamin A and LBR, causes a shift of H3K9me3-enriched LADs from lamina to nucleolus, and a reciprocal relocation of H3K27me3-enriched partially repressed iLADs from nucleolus to lamina. Thus, these partially repressed iLADs appear to compete with LADs for nuclear lamina attachment with consequences for replication timing. The nuclear organization in adherent cells is polarized with nuclear bodies and genomic regions segregating both radially and relative to the equatorial plane. Together, our results underscore the importance of considering genome organization relative to nuclear locales for a more complete understanding of the spatial and functional organization of the human genome.
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3
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Phan LMU, Yeo WH, Zhang HF, Huang S. Dynamic chromosome association with nuclear organelles in living cells. Histochem Cell Biol 2024; 162:149-159. [PMID: 38811432 DOI: 10.1007/s00418-024-02288-8] [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] [Accepted: 04/08/2024] [Indexed: 05/31/2024]
Abstract
The development of progressively sophisticated tools complemented by the integration of live cell imaging enhances our understanding of the four-dimensional (4D) nucleome, revealing elaborate molecular interactions and chromatin states. Yet, the dynamics of chromosomes in relation to nuclear organelles or to each other across cell cycle in living cells are underexplored. We have developed photoconvertible GFP H3-Dendra2 stably expressing in PC3M cells. The nuclear lamina and perinucleolar associated heterochromatin or diffuse chromosome regions were photoconverted through a single-point activation using a confocal microscope. The results demonstrated a dynamic nature for both types of chromosomes in the same cell cycle and across mitosis. While some chromosome domains were heritably associated with either nuclear lamina or nucleoli, others changed alliance to different nuclear organelles postmitotically. In addition, co-photoconverted chromosome domains often do not stay together within the same cell cycle and across mitosis, suggesting a transient nature of chromosome neighborhoods. Long-range spreading and movement of chromosomes were also observed. Interestingly, when cells were treated with a low concentration of actinomycin D that inhibits Pol I transcription through intercalating GC-rich DNA, chromosome movement was significantly blocked. Treatment with another Pol I inhibitor, metarrestin, which does not impact DNA, had little effect on the movement, suggesting that the DNA structure itself plays a role in chromosome dynamics. Furthermore, inhibition of Pol II transcription with α-amanitin also reduced the chromosome movement, demonstrating that Pol II, but not Pol I transcription, is important for chromosome dynamics in the nucleus.
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Affiliation(s)
- Lam Minh Uyen Phan
- Department of Cell and Developmental Biology, Northwestern University, Chicago, IL, USA
| | - Wei-Hong Yeo
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University, Chicago, IL, USA.
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4
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Yue B, Wang HY, Huang Y, Li S, Ma W, Liu Q, Shao C. Molecular functional characterization of the setdb1 and its potential target gene sox5 illuminate the histone modification-mediated orchestration of gonadal development in Chinese tongue sole (Cynoglossus semilaevis). Gene 2024; 901:148199. [PMID: 38253299 DOI: 10.1016/j.gene.2024.148199] [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: 10/16/2023] [Revised: 12/31/2023] [Accepted: 01/19/2024] [Indexed: 01/24/2024]
Abstract
SET (SuVar3-9, Enhancer of Zeste, Trithorax) domain bifurcated histone lysine methyltransferase 1, setdb1, is the predominant histone lysine methyltransferase catalyzing H3K9me3. Prior studies have illustrated that setdb1 and H3K9me3 critically regulate sex differentiation and gametogenesis. However, the molecular details by which setdb1 is involved in these processes in fish have been poorly reported. Here, we cloned and characterized the setdb1 ORF (open reading frame) sequence from Chinese tongue sole (Cynoglossus semilaevis). The setdb1 ORF sequence was 3,669 bp, encoding a 1,222-amino-acid protein. Phylogenetic analysis showed that setdb1 was structurally conserved. qRT-PCR revealed that setdb1 had a high expression level in the testes at 12 mpf (months post fertilization). Single-cell RNA-seq data at 24 mpf indicated that setdb1 was generally expressed in spermatogenic cells at each stage except for sperm and was centrally expressed in oogonia. H3K9me3 modification was observed in gonads with the immunofluorescence technique. Furthermore, the overexpression experiment suggested that sox5 was a candidate target of setdb1. sox5 was abundantly expressed in male and pseudomale gonads at 24 mpf. Single-cell RNA-seq data showed that sox5 was mainly expressed in spermatogonia and its expression gradually declined with differentiation. Taken together, our findings imply that setdb1 regulates sox5 transcription in gonads, which provides molecular clues into histone modification-mediated orchestration of sex differentiation and gametogenesis.
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Affiliation(s)
- Bowen Yue
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China; State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China
| | - Hong-Yan Wang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Yingyi Huang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Shuo Li
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Wenxiu Ma
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Qian Liu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Changwei Shao
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China.
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5
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Kumari A, Vertii A. Perspective: "Current understanding of NADs dynamics and mechanisms of Disease". Gene 2024; 894:147960. [PMID: 37923094 DOI: 10.1016/j.gene.2023.147960] [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: 07/27/2023] [Revised: 10/09/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
Chromatin architecture is essential for gene regulation, and multiple levels of the 3D chromatin organization exhibit dynamic changes during organismal development and cell differentiation. Heterochromatin, termed compartment B in Hi-C datasets, is a phase-separating gene-silencing form of chromatin, preferentially located at the two nuclear sites, nuclear (lamina-associate chromatin domains, LADs) and nucleoli (nucleoli-associated chromatin domains, NADs) peripheries. LADs and NADs contain both interchangeable and location-specific chromatin domains. Recent studies suggest striking dynamics in LADs and NADs during the differentiation of embryonic stem cells into neural progenitors and neurons. Here we discuss recent advances in understanding NADs changes during neuronal differentiation and future questions on how NADs integrity can contribute to healthy neurodevelopment and neurodevelopment diseases.
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Affiliation(s)
- Amrita Kumari
- Department of Molecular, Cellular and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 1605, US
| | - Anastassiia Vertii
- Department of Molecular, Cellular and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 1605, US.
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6
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Willemin A, Szabó D, Pombo A. Epigenetic regulatory layers in the 3D nucleus. Mol Cell 2024; 84:415-428. [PMID: 38242127 PMCID: PMC10872226 DOI: 10.1016/j.molcel.2023.12.032] [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: 07/26/2023] [Revised: 11/21/2023] [Accepted: 12/15/2023] [Indexed: 01/21/2024]
Abstract
Nearly 7 decades have elapsed since Francis Crick introduced the central dogma of molecular biology, as part of his ideas on protein synthesis, setting the fundamental rules of sequence information transfer from DNA to RNAs and proteins. We have since learned that gene expression is finely tuned in time and space, due to the activities of RNAs and proteins on regulatory DNA elements, and through cell-type-specific three-dimensional conformations of the genome. Here, we review major advances in genome biology and discuss a set of ideas on gene regulation and highlight how various biomolecular assemblies lead to the formation of structural and regulatory features within the nucleus, with roles in transcriptional control. We conclude by suggesting further developments that will help capture the complex, dynamic, and often spatially restricted events that govern gene expression in mammalian cells.
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Affiliation(s)
- Andréa Willemin
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany.
| | - Dominik Szabó
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany
| | - Ana Pombo
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Epigenetic Regulation and Chromatin Architecture Group, Berlin, Germany; Humboldt-Universität zu Berlin, Institute for Biology, Berlin, Germany.
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7
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Kołacz K, Robaszkiewicz A. PARP1 at the crossroad of cellular senescence and nucleolar processes. Ageing Res Rev 2024; 94:102206. [PMID: 38278370 DOI: 10.1016/j.arr.2024.102206] [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: 11/07/2023] [Revised: 01/09/2024] [Accepted: 01/22/2024] [Indexed: 01/28/2024]
Abstract
Senescent cells that occur in response to telomere shortening, oncogenes, extracellular and intracellular stress factors are characterized by permanent cell cycle arrest, the morphological and structural changes of the cell that include the senescence-associated secretory phenotype (SASP) and nucleoli rearrangement. The associated DNA lesions induce DNA damage response (DDR), which activates the DNA repair protein - poly-ADP-ribose polymerase 1 (PARP1). This protein consumes NAD+ to synthesize ADP-ribose polymer (PAR) on its own protein chain and on other interacting proteins. The involvement of PARP1 in nucleoli processes, such as rRNA transcription and ribosome biogenesis, the maintenance of heterochromatin and nucleoli structure, as well as controlling the crucial DDR protein release from the nucleoli to nucleus, links PARP1 with cellular senescence and nucleoli functioning. In this review we describe and discuss the impact of PARP1-mediated ADP-ribosylation on early cell commitment to senescence with the possible role of senescence-induced PARP1 transcriptional repression and protein degradation on nucleoli structure and function. The cause-effect interplay between PARP1 activation/decline and nucleoli functioning during senescence needs to be studied in detail.
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Affiliation(s)
- Kinga Kołacz
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; Bio-Med-Chem Doctoral School of the University of Lodz and Lodz Institutes of the Polish Academy of Sciences, University of Lodz, Banacha 12 /16, 90-237 Lodz, Poland.
| | - Agnieszka Robaszkiewicz
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland; Johns Hopkins University School of Medicine, Institute for Fundamental Biomedical Research (IFBR), 600 5th Street South, St. Petersburgh, FL 33701, USA.
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8
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Ogienko AA, Korepina MO, Pindyurin AV, Omelina ES. New Functional Motifs for the Targeted Localization of Proteins to the Nucleolus in Drosophila and Human Cells. Int J Mol Sci 2024; 25:1230. [PMID: 38279227 PMCID: PMC10817092 DOI: 10.3390/ijms25021230] [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: 12/14/2023] [Revised: 01/15/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
The nucleolus is a significant nuclear organelle that is primarily known for its role in ribosome biogenesis. However, emerging evidence suggests that the nucleolus may have additional functions. Particularly, it is involved in the organization of the three-dimensional structure of the genome. The nucleolus acts as a platform for the clustering of repressed chromatin, although this process is not yet fully understood, especially in the context of Drosophila. One way to study the regions of the genome that cluster near the nucleolus in Drosophila demands the identification of a reliable nucleolus-localizing signal (NoLS) motif(s) that can highly specifically recruit the protein of interest to the nucleolus. Here, we tested a series of various NoLS motifs from proteins of different species, as well as some of their combinations, for the ability to drive the nucleolar localization of the chimeric H2B-GFP protein. Several short motifs were found to effectively localize the H2B-GFP protein to the nucleolus in over 40% of transfected Drosophila S2 cells. Furthermore, it was demonstrated that NoLS motifs derived from Drosophila proteins exhibited greater efficiency compared to that of those from other species.
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Affiliation(s)
- Anna A. Ogienko
- Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
| | | | | | - Evgeniya S. Omelina
- Institute of Molecular and Cellular Biology, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
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9
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Kiseleva AA, Cheng YC, Smith CL, Katz RA, Poleshko A. PRR14 organizes H3K9me3-modified heterochromatin at the nuclear lamina. Nucleus 2023; 14:2165602. [PMID: 36633363 PMCID: PMC9839372 DOI: 10.1080/19491034.2023.2165602] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The eukaryotic genome is organized in three dimensions within the nucleus. Transcriptionally active chromatin is spatially separated from silent heterochromatin, a large fraction of which is located at the nuclear periphery. However, the mechanisms by which chromatin is localized at the nuclear periphery remain poorly understood. Here we demonstrate that Proline Rich 14 (PRR14) protein organizes H3K9me3-modified heterochromatin at the nuclear lamina. We show that PRR14 dynamically associates with both the nuclear lamina and heterochromatin, and is able to reorganize heterochromatin in the nucleus of interphase cells independent of mitosis. We characterize two functional HP1-binding sites within PRR14 that contribute to its association with heterochromatin. We also demonstrate that PPR14 forms an anchoring surface for heterochromatin at the nuclear lamina where it interacts dynamically with HP1-associated chromatin. Our study proposes a model of dynamic heterochromatin organization at the nuclear lamina via the PRR14 tethering protein.
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Affiliation(s)
- Anna A. Kiseleva
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu-Chia Cheng
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cheryl L. Smith
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Richard A. Katz
- Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - Andrey Poleshko
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA,CONTACT Andrey Poleshko Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, SCTR 09-188, 3400 Civic Center Blvd. Philadelphia, PA19104
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10
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Kumar P, Gholamalamdari O, Zhang Y, Zhang L, Vertii A, van Schaik T, Peric-Hupkes D, Sasaki T, Gilbert DM, van Steensel B, Ma J, Kaufman PD, Belmont AS. Nucleolus and centromere TSA-Seq reveals variable localization of heterochromatin in different cell types. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.29.564613. [PMID: 37961445 PMCID: PMC10634939 DOI: 10.1101/2023.10.29.564613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Genome differential positioning within interphase nuclei remains poorly explored. We extended and validated TSA-seq to map genomic regions near nucleoli and pericentric heterochromatin in four human cell lines. Our study confirmed that smaller chromosomes localize closer to nucleoli but further deconvolved this by revealing a preference for chromosome arms below 36-46 Mbp in length. We identified two lamina associated domain subsets through their differential nuclear lamina versus nucleolar positioning in different cell lines which showed distinctive patterns of DNA replication timing and gene expression across all cell lines. Unexpectedly, active, nuclear speckle-associated genomic regions were found near typically repressive nuclear compartments, which is attributable to the close proximity of nuclear speckles and nucleoli in some cell types, and association of centromeres with nuclear speckles in hESCs. Our study points to a more complex and variable nuclear genome organization than suggested by current models, as revealed by our TSA-seq methodology.
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11
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Alagna NS, Thomas TI, Wilson KL, Reddy KL. Choreography of lamina-associated domains: structure meets dynamics. FEBS Lett 2023; 597:2806-2822. [PMID: 37953467 PMCID: PMC10858991 DOI: 10.1002/1873-3468.14771] [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: 08/07/2023] [Revised: 09/13/2023] [Accepted: 09/17/2023] [Indexed: 11/14/2023]
Abstract
Lamina-associated domains are large regions of heterochromatin positioned at the nuclear periphery. These domains have been implicated in gene repression, especially in the context of development. In mammals, LAD organization is dependent on nuclear lamins, inner nuclear membrane proteins, and chromatin state. In addition, chromatin readers and modifier proteins have been implicated in this organization, potentially serving as molecular tethers that interact with both nuclear envelope proteins and chromatin. More recent studies have focused on teasing apart the rules that govern dynamic LAD organization and how LAD organization, in turn, relates to gene regulation and overall 3D genome organization. This review highlights recent studies in mammalian cells uncovering factors that instruct the choreography of LAD organization, re-organization, and dynamics at the nuclear lamina, including LAD dynamics in interphase and through mitotic exit, when LAD organization is re-established, as well as intra-LAD subdomain variations.
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Affiliation(s)
- Nicholas S. Alagna
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Tiera I. Thomas
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Katherine L. Wilson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Karen L. Reddy
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
- Sidney Kimmel Comprehensive Cancer Center, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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12
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Liu H, Caliz AD, Learnard H, Koupenova M, Keaney JF, Kant S, Zhu LJ, Vertii A. Inflammatory stress-mediated chromatin changes underlie dysfunction in endothelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.11.561959. [PMID: 37905100 PMCID: PMC10614786 DOI: 10.1101/2023.10.11.561959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Inflammatory stresses underlie endothelial dysfunction and contribute to the development of chronic cardiovascular disorders such as atherosclerosis and vascular fibrosis. The initial transcriptional response of endothelial cells to pro-inflammatory cytokines such as TNF-alpha is well established. However, very few studies uncover the effects of inflammatory stresses on chromatin architecture. We used integrative analysis of ATAC-seq and RNA-seq data to investigate chromatin alterations in human endothelial cells in response to TNF-alpha and febrile-range heat stress exposure. Multi-omics data analysis suggests a correlation between the transcription of stress-related genes and endothelial dysfunction drivers with chromatin regions exhibiting differential accessibility. Moreover, microscopy identified the dynamics in the nuclear organization, specifically, the changes in a subset of heterochromatic nucleoli-associated chromatin domains, the centromeres. Upon inflammatory stress exposure, the centromeres decreased association with nucleoli in a p38-dependent manner and increased the number of transcripts from pericentromeric regions. Overall, we provide two lines of evidence that suggest chromatin alterations in vascular endothelial cells during inflammatory stresses.
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Affiliation(s)
- Haibo Liu
- Molecular, Cell and Cancer Biology Department, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Amada D. Caliz
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Heather Learnard
- Cardiovascular Medicine, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Milka Koupenova
- Cardiovascular Medicine, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - John F. Keaney
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Shashi Kant
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Lihua Julie Zhu
- Molecular, Cell and Cancer Biology Department, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Molecular Medicine, Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Anastassiia Vertii
- Molecular, Cell and Cancer Biology Department, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Program in Innate Immunity, University of Massachusetts Chan Medical School, Worcester, MA, USA
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13
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Izzo A, Akol I, Villarreal A, Lebel S, Garcia-Miralles M, Cheffer A, Bovio P, Heidrich S, Vogel T. Nucleophosmin 1 cooperates with the methyltransferase DOT1L to preserve peri-nucleolar heterochromatin organization by regulating H3K27me3 levels and DNA repeats expression. Epigenetics Chromatin 2023; 16:36. [PMID: 37759327 PMCID: PMC10537513 DOI: 10.1186/s13072-023-00511-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND NPM1 is a phosphoprotein highly abundant in the nucleolus. However, additional nuclear functions have been attributed to NPM1, probably through interaction with other nuclear factors. DOT1L is one interaction partner of NPM1 that catalyzes methylation of histone H3 at lysine 79 (H3K79). DOT1L, playing functional roles in several biological processes, is known for its capability to organize and regulate chromatin. For example, DOT1L modulates DNA repeats expression within peri-nucleolar heterochromatin. NPM1 also affects peri-nucleolar heterochromatin spatial organization. However, it is unclear as of yet whether NPM1 and DOT1L functionally synergize to preserve nucleoli organization and genome stability, and generally, which molecular mechanisms would be involved. RESULTS We characterized the nuclear function of NPM1 on peri-nucleolar heterochromatin organization. We show that (i) monomeric NPM1 interacts preferentially with DOT1L in the nucleus; (ii) NPM1 acts in concert with DOT1L to maintain each other's protein homeostasis; (iii) NPM1 depletion results in H3K79me2 upregulation and differential enrichment at chromatin binding genes including Ezh2; (iv) NPM1 and DOT1L modulate DNA repeats expression and peri-nucleolar heterochromatin organization via epigenetic mechanisms dependent on H3K27me3. CONCLUSIONS Our findings give insights into molecular mechanisms employed by NPM1 and DOT1L to regulate heterochromatin activity and structural organization around the nucleoli and shed light on one aspect of the complex role of both proteins in chromatin dynamics.
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Affiliation(s)
- Annalisa Izzo
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.
| | - Ipek Akol
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University of Freiburg, 79104, Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModul Basics), Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Alejandro Villarreal
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
- Laboratorio de Neuropatología Molecular, Facultad de Medicina, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" UBA-CONICET, Universidad de Buenos Aires, 1121, Buenos Aires, Argentina
| | - Shannon Lebel
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Marta Garcia-Miralles
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Arquimedes Cheffer
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Patrick Bovio
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Stefanie Heidrich
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
| | - Tanja Vogel
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.
- Center for Basics in NeuroModulation (NeuroModul Basics), Medical Faculty, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany.
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14
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Freeman TF, Zhao Q, Surya A, Rothe R, Cenik ES. Ribosome biogenesis disruption mediated chromatin structure changes revealed by SRAtac, a customizable end to end analysis pipeline for ATAC-seq. BMC Genomics 2023; 24:512. [PMID: 37658321 PMCID: PMC10472662 DOI: 10.1186/s12864-023-09576-y] [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: 11/10/2022] [Accepted: 08/11/2023] [Indexed: 09/03/2023] Open
Abstract
The nucleolus is a large nuclear body that serves as the primary site for ribosome biogenesis. Recent studies have suggested that it also plays an important role in organizing chromatin architecture. However, to establish a causal relationship between nucleolar ribosome assembly and chromatin architecture, genetic tools are required to disrupt nucleolar ribosome biogenesis. In this study, we used ATAC-seq to investigate changes in chromatin accessibility upon specific depletion of two ribosome biogenesis components, RPOA-2 and GRWD-1, in the model organism Caenorhabditis elegans. To facilitate the analysis of ATAC-seq data, we introduced two tools: SRAlign, an extensible NGS data processing workflow, and SRAtac, a customizable end-to-end ATAC-seq analysis pipeline. Our results revealed highly comparable changes in chromatin accessibility following both RPOA-2 and GRWD-1 perturbations. However, we observed a weak correlation between changes in chromatin accessibility and gene expression. While our findings corroborate the idea of a feedback mechanism between ribosomal RNA synthesis, nucleolar ribosome large subunit biogenesis, and chromatin structure during the L1 stage of C. elegans development, they also prompt questions regarding the functional impact of these alterations on gene expression.
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Affiliation(s)
- Trevor F Freeman
- Department of Molecular Biosciences, University of Texas, Austin, TX, 78712, USA
| | - Qiuxia Zhao
- Department of Molecular Biosciences, University of Texas, Austin, TX, 78712, USA
| | - Agustian Surya
- Department of Molecular Biosciences, University of Texas, Austin, TX, 78712, USA
| | - Reed Rothe
- Department of Molecular Biosciences, University of Texas, Austin, TX, 78712, USA
| | - Elif Sarinay Cenik
- Department of Molecular Biosciences, University of Texas, Austin, TX, 78712, USA.
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15
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Senapati S, Irshad IU, Sharma AK, Kumar H. Fundamental insights into the correlation between chromosome configuration and transcription. Phys Biol 2023; 20:051002. [PMID: 37467757 DOI: 10.1088/1478-3975/ace8e5] [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: 04/18/2023] [Accepted: 07/19/2023] [Indexed: 07/21/2023]
Abstract
Eukaryotic chromosomes exhibit a hierarchical organization that spans a spectrum of length scales, ranging from sub-regions known as loops, which typically comprise hundreds of base pairs, to much larger chromosome territories that can encompass a few mega base pairs. Chromosome conformation capture experiments that involve high-throughput sequencing methods combined with microscopy techniques have enabled a new understanding of inter- and intra-chromosomal interactions with unprecedented details. This information also provides mechanistic insights on the relationship between genome architecture and gene expression. In this article, we review the recent findings on three-dimensional interactions among chromosomes at the compartment, topologically associating domain, and loop levels and the impact of these interactions on the transcription process. We also discuss current understanding of various biophysical processes involved in multi-layer structural organization of chromosomes. Then, we discuss the relationships between gene expression and genome structure from perturbative genome-wide association studies. Furthermore, for a better understanding of how chromosome architecture and function are linked, we emphasize the role of epigenetic modifications in the regulation of gene expression. Such an understanding of the relationship between genome architecture and gene expression can provide a new perspective on the range of potential future discoveries and therapeutic research.
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Affiliation(s)
- Swayamshree Senapati
- School of Basic Sciences, Indian Institute of Technology, Bhubaneswar, Argul, Odisha 752050, India
| | - Inayat Ullah Irshad
- Department of Physics, Indian Institute of Technology, Jammu, Jammu 181221, India
| | - Ajeet K Sharma
- Department of Physics, Indian Institute of Technology, Jammu, Jammu 181221, India
- Department of Biosciences and Bioengineering, Indian Institute of Technology Jammu, Jammu 181221, India
| | - Hemant Kumar
- School of Basic Sciences, Indian Institute of Technology, Bhubaneswar, Argul, Odisha 752050, India
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16
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Yildirim A, Hua N, Boninsegna L, Zhan Y, Polles G, Gong K, Hao S, Li W, Zhou XJ, Alber F. Evaluating the role of the nuclear microenvironment in gene function by population-based modeling. Nat Struct Mol Biol 2023; 30:1193-1206. [PMID: 37580627 PMCID: PMC10442234 DOI: 10.1038/s41594-023-01036-1] [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: 11/03/2021] [Accepted: 06/16/2023] [Indexed: 08/16/2023]
Abstract
The nuclear folding of chromosomes relative to nuclear bodies is an integral part of gene function. Here, we demonstrate that population-based modeling-from ensemble Hi-C data-provides a detailed description of the nuclear microenvironment of genes and its role in gene function. We define the microenvironment by the subnuclear positions of genomic regions with respect to nuclear bodies, local chromatin compaction, and preferences in chromatin compartmentalization. These structural descriptors are determined in single-cell models, thereby revealing the structural variability between cells. We demonstrate that the microenvironment of a genomic region is linked to its functional potential in gene transcription, replication, and chromatin compartmentalization. Some chromatin regions feature a strong preference for a single microenvironment, due to association with specific nuclear bodies in most cells. Other chromatin shows high structural variability, which is a strong indicator of functional heterogeneity. Moreover, we identify specialized nuclear microenvironments, which distinguish chromatin in different functional states and reveal a key role of nuclear speckles in chromosome organization. We demonstrate that our method produces highly predictive three-dimensional genome structures, which accurately reproduce data from a variety of orthogonal experiments, thus considerably expanding the range of Hi-C data analysis.
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Affiliation(s)
- Asli Yildirim
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Nan Hua
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Lorenzo Boninsegna
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Yuxiang Zhan
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Guido Polles
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Ke Gong
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Shengli Hao
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA
| | - Wenyuan Li
- Department of Pathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Xianghong Jasmine Zhou
- Department of Pathology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Frank Alber
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA.
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17
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Hernández‐Carralero E, Cabrera E, Rodríguez-Torres G, Hernández-Reyes Y, Singh A, Santa-María C, Fernández-Justel J, Janssens R, Marteijn J, Evert B, Mailand N, Gómez M, Ramadan K, Smits VJ, Freire R. ATXN3 controls DNA replication and transcription by regulating chromatin structure. Nucleic Acids Res 2023; 51:5396-5413. [PMID: 36971114 PMCID: PMC10287915 DOI: 10.1093/nar/gkad212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 02/10/2023] [Accepted: 03/14/2023] [Indexed: 11/18/2023] Open
Abstract
The deubiquitinating enzyme Ataxin-3 (ATXN3) contains a polyglutamine (PolyQ) region, the expansion of which causes spinocerebellar ataxia type-3 (SCA3). ATXN3 has multiple functions, such as regulating transcription or controlling genomic stability after DNA damage. Here we report the role of ATXN3 in chromatin organization during unperturbed conditions, in a catalytic-independent manner. The lack of ATXN3 leads to abnormalities in nuclear and nucleolar morphology, alters DNA replication timing and increases transcription. Additionally, indicators of more open chromatin, such as increased mobility of histone H1, changes in epigenetic marks and higher sensitivity to micrococcal nuclease digestion were detected in the absence of ATXN3. Interestingly, the effects observed in cells lacking ATXN3 are epistatic to the inhibition or lack of the histone deacetylase 3 (HDAC3), an interaction partner of ATXN3. The absence of ATXN3 decreases the recruitment of endogenous HDAC3 to the chromatin, as well as the HDAC3 nuclear/cytoplasm ratio after HDAC3 overexpression, suggesting that ATXN3 controls the subcellular localization of HDAC3. Importantly, the overexpression of a PolyQ-expanded version of ATXN3 behaves as a null mutant, altering DNA replication parameters, epigenetic marks and the subcellular distribution of HDAC3, giving new insights into the molecular basis of the disease.
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Affiliation(s)
- Esperanza Hernández‐Carralero
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de la Laguna, Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Campus Ciencias de la Salud, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Elisa Cabrera
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
| | - Gara Rodríguez-Torres
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de la Laguna, Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Campus Ciencias de la Salud, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Yeray Hernández-Reyes
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de la Laguna, Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Campus Ciencias de la Salud, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Abhay N Singh
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Cristina Santa-María
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Madrid, Spain
| | - José Miguel Fernández-Justel
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Madrid, Spain
| | - Roel C Janssens
- Department of Molecular Genetics, Oncode Institute, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jurgen A Marteijn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Bernd O Evert
- Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Niels Mailand
- Protein Signaling Program, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - María Gómez
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Madrid, Spain
| | - Kristijan Ramadan
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK
| | - Veronique A J Smits
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Campus Ciencias de la Salud, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
- Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, Spain
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, La Laguna, Santa Cruz de Tenerife, Spain
- Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Facultad de Medicina, Campus Ciencias de la Salud, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
- Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, Spain
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18
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Qiu Y, Feng D, Jiang W, Zhang T, Lu Q, Zhao M. 3D genome organization and epigenetic regulation in autoimmune diseases. Front Immunol 2023; 14:1196123. [PMID: 37346038 PMCID: PMC10279977 DOI: 10.3389/fimmu.2023.1196123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/17/2023] [Indexed: 06/23/2023] Open
Abstract
Three-dimensional (3D) genomics is an emerging field of research that investigates the relationship between gene regulatory function and the spatial structure of chromatin. Chromatin folding can be studied using chromosome conformation capture (3C) technology and 3C-based derivative sequencing technologies, including chromosome conformation capture-on-chip (4C), chromosome conformation capture carbon copy (5C), and high-throughput chromosome conformation capture (Hi-C), which allow scientists to capture 3D conformations from a single site to the entire genome. A comprehensive analysis of the relationships between various regulatory components and gene function also requires the integration of multi-omics data such as genomics, transcriptomics, and epigenomics. 3D genome folding is involved in immune cell differentiation, activation, and dysfunction and participates in a wide range of diseases, including autoimmune diseases. We describe hierarchical 3D chromatin organization in this review and conclude with characteristics of C-techniques and multi-omics applications of the 3D genome. In addition, we describe the relationship between 3D genome structure and the differentiation and maturation of immune cells and address how changes in chromosome folding contribute to autoimmune diseases.
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Affiliation(s)
- Yueqi Qiu
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
- Key Laboratory of Basic and Translational Research on Immune-Mediated Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
| | - Delong Feng
- Department of Dermatology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Wenjuan Jiang
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
- Key Laboratory of Basic and Translational Research on Immune-Mediated Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
| | - Tingting Zhang
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
- Key Laboratory of Basic and Translational Research on Immune-Mediated Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Qianjin Lu
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
- Key Laboratory of Basic and Translational Research on Immune-Mediated Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
- Department of Dermatology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Ming Zhao
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
- Key Laboratory of Basic and Translational Research on Immune-Mediated Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
- Department of Dermatology, The Second Xiangya Hospital of Central South University, Changsha, China
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19
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Zheng X, Tran JR, Zheng Y. CscoreTool-M infers 3D sub-compartment probabilities within cell population. Bioinformatics 2023; 39:btad314. [PMID: 37166448 PMCID: PMC10206090 DOI: 10.1093/bioinformatics/btad314] [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: 07/26/2022] [Revised: 02/07/2023] [Accepted: 05/10/2023] [Indexed: 05/12/2023] Open
Abstract
MOTIVATION Computational inference of genome organization based on Hi-C sequencing has greatly aided the understanding of chromatin and nuclear organization in three dimensions (3D). However, existing computational methods fail to address the cell population heterogeneity. Here we describe a probabilistic-modeling-based method called CscoreTool-M that infers multiple 3D genome sub-compartments from Hi-C data. RESULTS The compartment scores inferred using CscoreTool-M represents the probability of a genomic region locating in a specific sub-compartment. Compared to published methods, CscoreTool-M is more accurate in inferring sub-compartments corresponding to both active and repressed chromatin. The compartment scores calculated by CscoreTool-M also help to quantify the levels of heterogeneity in sub-compartment localization within cell populations. By comparing proliferating cells and terminally differentiated non-proliferating cells, we show that the proliferating cells have higher genome organization heterogeneity, which is likely caused by cells at different cell-cycle stages. By analyzing 10 sub-compartments, we found a sub-compartment containing chromatin potentially related to the early-G1 chromatin regions proximal to the nuclear lamina in HCT116 cells, suggesting the method can deconvolve cell cycle stage-specific genome organization among asynchronously dividing cells. Finally, we show that CscoreTool-M can identify sub-compartments that contain genes enriched in housekeeping or cell-type-specific functions. AVAILABILITY AND IMPLEMENTATION https://github.com/scoutzxb/CscoreTool-M.
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Affiliation(s)
- Xiaobin Zheng
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, United States
| | - Joseph R Tran
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, United States
| | - Yixian Zheng
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, United States
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20
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Rodrigues A, MacQuarrie KL, Freeman E, Lin A, Willis AB, Xu Z, Alvarez AA, Ma Y, White BEP, Foltz DR, Huang S. Nucleoli and the nucleoli-centromere association are dynamic during normal development and in cancer. Mol Biol Cell 2023; 34:br5. [PMID: 36753381 PMCID: PMC10092642 DOI: 10.1091/mbc.e22-06-0237] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 01/19/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
Centromeres are known to cluster around nucleoli in Drosophila and mammalian cells, but the significance of the nucleoli-centromere interaction remains underexplored. To determine whether the interaction is dynamic under different physiological and pathological conditions, we examined nucleolar structure and centromeres at various differentiation stages using cell culture models and the results showed dynamic changes in nucleolar characteristics and nucleoli-centromere interactions through differentiation and in cancer cells. Embryonic stem cells usually have a single large nucleolus, which is clustered with a high percentage of centromeres. As cells differentiate into intermediate states, the nucleolar number increases and the centromere association decreases. In terminally differentiated cells, including myotubes, neurons, and keratinocytes, the number of nucleoli and their association with centromeres are at the lowest. Cancer cells demonstrate the pattern of nucleoli number and nucleoli-centromere association that is akin to proliferative cell types, suggesting that nucleolar reorganization and changes in nucleoli-centromere interactions may play a role in facilitating malignant transformation. This idea is supported in a case of pediatric rhabdomyosarcoma, in which induced differentiation reduces the nucleolar number and centromere association. These findings suggest active roles of nucleolar structure in centromere function and genome organization critical for cellular function in both normal development and cancer.
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Affiliation(s)
- Aaron Rodrigues
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Kyle L. MacQuarrie
- Division of Hematology, Oncology, and Stem Cell Transplantation, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Emma Freeman
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Alicia Lin
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Alexander B. Willis
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Zhaofa Xu
- Departments of Pediatrics, Neurology and Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
- Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 60611
| | - Angel A. Alvarez
- Stem Cell Core and Ken & Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Yongchao Ma
- Departments of Pediatrics, Neurology and Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
- Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL 60611
| | - Bethany E. Perez White
- Department of Dermatology and Skin Biology and Diseases Resource-based Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Daniel R. Foltz
- Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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21
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Guthmann M, Qian C, Gialdini I, Nakatani T, Ettinger A, Schauer T, Kukhtevich I, Schneider R, Lamb DC, Burton A, Torres-Padilla ME. A change in biophysical properties accompanies heterochromatin formation in mouse embryos. Genes Dev 2023; 37:336-350. [PMID: 37072228 PMCID: PMC10153458 DOI: 10.1101/gad.350353.122] [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: 12/13/2022] [Accepted: 03/31/2023] [Indexed: 04/20/2023]
Abstract
The majority of our genome is composed of repeated DNA sequences that assemble into heterochromatin, a highly compacted structure that constrains their mutational potential. How heterochromatin forms during development and how its structure is maintained are not fully understood. Here, we show that mouse heterochromatin phase-separates after fertilization, during the earliest stages of mammalian embryogenesis. Using high-resolution quantitative imaging and molecular biology approaches, we show that pericentromeric heterochromatin displays properties consistent with a liquid-like state at the two-cell stage, which change at the four-cell stage, when chromocenters mature and heterochromatin becomes silent. Disrupting the condensates results in altered transcript levels of pericentromeric heterochromatin, suggesting a functional role for phase separation in heterochromatin function. Thus, our work shows that mouse heterochromatin forms membrane-less compartments with biophysical properties that change during development and provides new insights into the self-organization of chromatin domains during mammalian embryogenesis.
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Affiliation(s)
- Manuel Guthmann
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Chen Qian
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Irene Gialdini
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Tsunetoshi Nakatani
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Andreas Ettinger
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Tamas Schauer
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Igor Kukhtevich
- Institute of Functional Epigenetics (IFE), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Robert Schneider
- Institute of Functional Epigenetics (IFE), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Don C Lamb
- Department of Chemistry, Center for NanoScience (CeNS), Ludwig Maximilians-Universität München, 81377 München, Germany
| | - Adam Burton
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany
| | - Maria-Elena Torres-Padilla
- Institute of Epigenetics and Stem Cells (IES), Helmholtz Zentrum München, D-81377 München, Germany;
- Faculty of Biology, Ludwig-Maximilians Universität, München, 82152 Planegg, Germany
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22
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Bersaglieri C, Santoro R. Methods for mapping 3D-chromosome architecture around nucleoli. Curr Opin Cell Biol 2023; 81:102171. [PMID: 37230037 DOI: 10.1016/j.ceb.2023.102171] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/03/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023]
Abstract
The nucleolus is the largest subcompartment of the nucleus, known to be the place of ribosome biogenesis. Emerging evidence has started to implicate the nucleolus in the organization of chromosomes in the nucleus. Genomic domains contacting the nucleolus are defined as nucleolar associated domains (NADs) and are generally characterized by repressive chromatin states. However, the role of the nucleolus in genome architecture remains still not fully understood mainly because the lack of a membrane has challenged the establishment of methods for accurate identification of NADs. Here, we will discuss recent advances on methods to identify and characterize NADs, discuss their improvements relative to old methods, and highlight future perspectives.
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Affiliation(s)
- Cristiana Bersaglieri
- Department of Molecular Mechanisms of Disease, DMMD, University of Zurich, Zurich, Switzerland
| | - Raffaella Santoro
- Department of Molecular Mechanisms of Disease, DMMD, University of Zurich, Zurich, Switzerland.
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23
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Wang C, Ma H, Baserga SJ, Pederson T, Huang S. Nucleolar structure connects with global nuclear organization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.534966. [PMID: 37034708 PMCID: PMC10081344 DOI: 10.1101/2023.03.30.534966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The nucleolus is a multi-functional nuclear body. To tease out the roles of nucleolar structure without resorting to multi-action drugs, we knocked down RNA polymerase I subunit RPA194 in HeLa cells by siRNA. Loss of RPA194 resulted in nucleolar structural segregation and effects on both nucleolus-proximal and distal nuclear components. The perinucleolar compartment was disrupted, centromere-nucleolus interactions were significantly reduced, and the intranuclear locations of specific genomic loci were altered. Moreover, Cajal bodies, distal from nucleoli, underwent morphological and compositional changes. To distinguish whether these global reorganizations are the results of nucleolar structural disruption or inhibition of ribosome synthesis, the pre-ribosomal RNA processing factor, UTP4, was also knocked down, which did not lead to nucleolar segregation, nor the intranuclear effects seen with RPA195A knockdown, demonstrating that they do not arise from a cessation of ribosome synthesis. These findings point to a commutative system that links nucleolar structure to the maintenance and spatial organization of certain nuclear bodies and genomic loci.
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Affiliation(s)
- Chen Wang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Hanhui Ma
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA
- School of Life Science and Technology, Shanghai Tech University, Shanghai, China
| | - Susan J Baserga
- Department of Genetics, Yale School of Medicine, New Haven, CT
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
- Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT
| | - Thoru Pederson
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL
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24
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Li X, An Z, Zhang W, Li F. Phase Separation: Direct and Indirect Driving Force for High-Order Chromatin Organization. Genes (Basel) 2023; 14:499. [PMID: 36833426 PMCID: PMC9956262 DOI: 10.3390/genes14020499] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
The multi-level spatial chromatin organization in the nucleus is closely related to chromatin activity. The mechanism of chromatin organization and remodeling attract much attention. Phase separation describes the biomolecular condensation which is the basis for membraneless compartments in cells. Recent research shows that phase separation is a key aspect to drive high-order chromatin structure and remodeling. In addition, chromatin functional compartmentalization in the nucleus which is formed by phase separation also plays an important role in overall chromatin structure. In this review, we summarized the latest work about the role of phase separation in spatial chromatin organization, focusing on direct and indirect effects of phase separation on 3D chromatin organization and its impact on transcription regulation.
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Affiliation(s)
- Xiaoli Li
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
- Department of Cell Biology and Genetics, Core Facility of Developmental Biology, Chongqing Medical University, Chongqing 400016, China
| | - Ziyang An
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China
| | - Wenqing Zhang
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Feifei Li
- Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
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25
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Roy AL, Conroy RS, Taylor VG, Mietz J, Fingerman IM, Pazin MJ, Smith P, Hutter CM, Singer DS, Wilder EL. Elucidating the structure and function of the nucleus-The NIH Common Fund 4D Nucleome program. Mol Cell 2023; 83:335-342. [PMID: 36640770 PMCID: PMC9898192 DOI: 10.1016/j.molcel.2022.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 01/15/2023]
Abstract
Genomic architecture appears to play crucial roles in health and a variety of diseases. How nuclear structures reorganize over different timescales is elusive, partly because the tools needed to probe and perturb them are not as advanced as needed by the field. To fill this gap, the National Institutes of Health Common Fund started a program in 2015, called the 4D Nucleome (4DN), with the goal of developing and ultimately applying technologies to interrogate the structure and function of nuclear organization in space and time.
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Affiliation(s)
- Ananda L Roy
- Office of Strategic Coordination, National Institutes of Health, Bethesda, MD 20892, USA; Division of Program Coordination, Planning, and Strategic Initiative, National Institutes of Health, Bethesda, MD 20892, USA; Office of the National Institutes of Health Director, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Richard S Conroy
- Office of Strategic Coordination, National Institutes of Health, Bethesda, MD 20892, USA; Division of Program Coordination, Planning, and Strategic Initiative, National Institutes of Health, Bethesda, MD 20892, USA; Office of the National Institutes of Health Director, National Institutes of Health, Bethesda, MD 20892, USA
| | - Veronica G Taylor
- Office of Strategic Coordination, National Institutes of Health, Bethesda, MD 20892, USA; Division of Program Coordination, Planning, and Strategic Initiative, National Institutes of Health, Bethesda, MD 20892, USA; Office of the National Institutes of Health Director, National Institutes of Health, Bethesda, MD 20892, USA
| | - Judy Mietz
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ian M Fingerman
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michael J Pazin
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Phillip Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Carolyn M Hutter
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dinah S Singer
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elizabeth L Wilder
- Office of Strategic Coordination, National Institutes of Health, Bethesda, MD 20892, USA; Division of Program Coordination, Planning, and Strategic Initiative, National Institutes of Health, Bethesda, MD 20892, USA; Office of the National Institutes of Health Director, National Institutes of Health, Bethesda, MD 20892, USA
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26
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Peng T, Hou Y, Meng H, Cao Y, Wang X, Jia L, Chen Q, Zheng Y, Sun Y, Chen H, Li T, Li C. Mapping nucleolus-associated chromatin interactions using nucleolus Hi-C reveals pattern of heterochromatin interactions. Nat Commun 2023; 14:350. [PMID: 36681699 PMCID: PMC9867699 DOI: 10.1038/s41467-023-36021-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 01/11/2023] [Indexed: 01/22/2023] Open
Abstract
As the largest substructures in the nucleus, nucleoli are the sites of ribosome biogenesis. Increasing evidence indicates that nucleoli play a key role in the organization of 3D genome architecture, but systematic studies of nucleolus-associated chromatin interactions are lacking. Here, we developed a nucleolus Hi-C (nHi-C) experimental technique to enrich nucleolus-associated chromatin interactions. Using the nHi-C experiment, we identify 264 high-confidence nucleolus-associated domains (hNADs) that form strong heterochromatin interactions associated with the nucleolus and consist of 24% of the whole genome in HeLa cells. Based on the global hNAD inter-chromosomal interactions, we find five nucleolar organizer region (NOR)-bearing chromosomes formed into two clusters that show different interaction patterns, which is concordant with their epigenetic states and gene expression levels. hNADs can be divided into three groups that display distinct cis/trans interaction signals, interaction frequencies associated with nucleoli, distance from the centromeres, and overlap percentage with lamina-associated domains (LADs). Nucleolus disassembly caused by Actinomycin D (ActD) significantly decreases the strength of hNADs and affects compartment/TAD strength genome-wide. In summary, our results provide a global view of heterochromatin interactions organized around nucleoli and demonstrate that nucleoli act as an inactive inter-chromosomal hub to shape both compartments and TADs.
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Affiliation(s)
- Ting Peng
- School of Life Sciences, Peking University, Beijing, China
| | - Yingping Hou
- School of Life Sciences, Peking University, Beijing, China
| | - Haowei Meng
- School of Life Sciences, Peking University, Beijing, China
| | - Yong Cao
- National Institute of Biological Sciences, Beijing, China
| | - Xiaotian Wang
- School of Life Sciences, Peking University, Beijing, China
- State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, China
| | - Lumeng Jia
- School of Life Sciences, Peking University, Beijing, China
| | - Qing Chen
- Department of Biological Sciences, George Washington University Columbian College of Art and Sciences, Washington, DC, USA
| | - Yang Zheng
- Institute of Health Service and Transfusion Medicine, Beijing, China
| | - Yujie Sun
- State Key Laboratory of Membrane Biology, Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing, China
- National Biomedical Imaging Center, College of Future Technology, Peking University, Beijing, China
| | - Hebing Chen
- Institute of Health Service and Transfusion Medicine, Beijing, China
| | - Tingting Li
- State Key Laboratory of Proteomics, Institute of Basic Medical Sciences, National Center of Biomedical Analysis, Beijing, China.
| | - Cheng Li
- School of Life Sciences, Peking University, Beijing, China.
- Center for Statistical Science, Peking University, Beijing, China.
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27
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Roles of Polycomb Complexes in the Reconstruction of 3D Genome Architecture during Preimplantation Embryonic Development. Genes (Basel) 2022; 13:genes13122382. [PMID: 36553649 PMCID: PMC9778514 DOI: 10.3390/genes13122382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
The appropriate deployment of developmental programs depends on complex genetic information encoded by genomic DNA sequences and their positioning and contacts in the three-dimensional (3D) space within the nucleus. Current studies using novel techniques including, but not limited to, Hi-C, ChIA-PET, and Hi-ChIP reveal that regulatory elements (Res), such as enhancers and promoters, may participate in the precise regulation of expression of tissue-specific genes important for both embryogenesis and organogenesis by recruiting Polycomb Group (PcG) complexes. PcG complexes usually poise the transcription of developmental genes by forming Polycomb bodies to compact poised enhancers and promoters marked by H3K27me3 in the 3D space. Additionally, recent studies have also uncovered their roles in transcriptional activation. To better understand the full complexities in the mechanisms of how PcG complexes regulate transcription and long-range 3D contacts of enhancers and promoters during developmental programs, we outline novel insights regarding PcG-associated dramatic changes in the 3D chromatin conformation in developmental programs of early embryos and naïve-ground-state transitions of pluripotent embryonic stem cells (ESCs), and highlight the distinct roles of unique and common subunits of canonical and non-canonical PcG complexes in shaping genome architectures and transcriptional programs.
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28
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Amankwaa B, Schoborg T, Labrador M. Drosophila insulator proteins exhibit in vivo liquid-liquid phase separation properties. Life Sci Alliance 2022; 5:5/12/e202201536. [PMID: 35853678 PMCID: PMC9297610 DOI: 10.26508/lsa.202201536] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 11/24/2022] Open
Abstract
Drosophila insulator proteins and the cohesin subunit Rad21 coalesce in vivo to form liquid-droplet condensates, suggesting that liquid–liquid phase separation mediates their function in 3D genome organization. Mounting evidence implicates liquid–liquid phase separation (LLPS), the condensation of biomolecules into liquid-like droplets in the formation and dissolution of membraneless intracellular organelles (MLOs). Cells use MLOs or condensates for various biological processes, including emergency signaling and spatiotemporal control over steady-state biochemical reactions and heterochromatin formation. Insulator proteins are architectural elements involved in establishing independent domains of transcriptional activity within eukaryotic genomes. In Drosophila, insulator proteins form nuclear foci known as insulator bodies in response to osmotic stress. However, the mechanism through which insulator proteins assemble into bodies is yet to be investigated. Here, we identify signatures of LLPS by insulator bodies, including high disorder tendency in insulator proteins, scaffold–client–dependent assembly, extensive fusion behavior, sphericity, and sensitivity to 1,6-hexanediol. We also show that the cohesin subunit Rad21 is a component of insulator bodies, adding to the known insulator protein constituents and γH2Av. Our data suggest a concerted role of cohesin and insulator proteins in insulator body formation and under physiological conditions. We propose a mechanism whereby these architectural proteins modulate 3D genome organization through LLPS.
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Affiliation(s)
- Bright Amankwaa
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, USA
| | - Todd Schoborg
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, USA
| | - Mariano Labrador
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, USA
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29
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van Schaik T, Manzo SG, Vouzas AE, Liu NQ, Teunissen H, de Wit E, Gilbert DM, van Steensel B. Dynamic chromosomal interactions and control of heterochromatin positioning by Ki-67. EMBO Rep 2022; 23:e55782. [PMID: 36245428 PMCID: PMC9724667 DOI: 10.15252/embr.202255782] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022] Open
Abstract
Ki-67 is a chromatin-associated protein with a dynamic distribution pattern throughout the cell cycle and is thought to be involved in chromatin organization. The lack of genomic interaction maps has hampered a detailed understanding of its roles, particularly during interphase. By pA-DamID mapping in human cell lines, we find that Ki-67 associates with large genomic domains that overlap mostly with late-replicating regions. Early in interphase, when Ki-67 is present in pre-nucleolar bodies, it interacts with these domains on all chromosomes. However, later in interphase, when Ki-67 is confined to nucleoli, it shows a striking shift toward small chromosomes. Nucleolar perturbations indicate that these cell cycle dynamics correspond to nucleolar maturation during interphase, and suggest that nucleolar sequestration of Ki-67 limits its interactions with larger chromosomes. Furthermore, we demonstrate that Ki-67 does not detectably control chromatin-chromatin interactions during interphase, but it competes with the nuclear lamina for interaction with late-replicating DNA, and it controls replication timing of (peri)centromeric regions. Together, these results reveal a highly dynamic choreography of genome interactions and roles for Ki-67 in heterochromatin organization.
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Affiliation(s)
- Tom van Schaik
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Stefano G Manzo
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Athanasios E Vouzas
- Department of Biological ScienceThe Florida State UniversityTallahasseeFLUSA,San Diego Biomedical Research InstituteSan DiegoCAUSA
| | - Ning Qing Liu
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Hans Teunissen
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - Elzo de Wit
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands
| | - David M Gilbert
- Department of Biological ScienceThe Florida State UniversityTallahasseeFLUSA,San Diego Biomedical Research InstituteSan DiegoCAUSA
| | - Bas van Steensel
- Division of Gene Regulation and Oncode InstituteNetherlands Cancer InstituteAmsterdamThe Netherlands,Department of Cell BiologyErasmus University Medical CentreRotterdamThe Netherlands
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30
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Schneider MF, Müller V, Müller SA, Lichtenthaler SF, Becker PB, Scheuermann JC. LncRNA RUS shapes the gene expression program towards neurogenesis. Life Sci Alliance 2022; 5:5/10/e202201504. [PMID: 35688487 PMCID: PMC9187872 DOI: 10.26508/lsa.202201504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/13/2022] [Accepted: 05/13/2022] [Indexed: 11/29/2022] Open
Abstract
The chromatin-associated lncRNA RUS binds in the vicinity to neural differentiation-associated genes and regulates them in a context-dependent manner to enable proper neuron development. The evolution of brain complexity correlates with an increased expression of long, noncoding (lnc) RNAs in neural tissues. Although prominent examples illustrate the potential of lncRNAs to scaffold and target epigenetic regulators to chromatin loci, only few cases have been described to function during brain development. We present a first functional characterization of the lncRNA LINC01322, which we term RUS for “RNA upstream of Slitrk3.” The RUS gene is well conserved in mammals by sequence and synteny next to the neurodevelopmental gene Slitrk3. RUS is exclusively expressed in neural cells and its expression increases during neuronal differentiation of mouse embryonic cortical neural stem cells. Depletion of RUS locks neuronal precursors in an intermediate state towards neuronal differentiation resulting in arrested cell cycle and increased apoptosis. RUS associates with chromatin in the vicinity of genes involved in neurogenesis, most of which change their expression upon RUS depletion. The identification of a range of epigenetic regulators as specific RUS interactors suggests that the lncRNA may mediate gene activation and repression in a highly context-dependent manner.
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Affiliation(s)
- Marius F Schneider
- Division of Molecular Biology, Biomedical Center Munich, Ludwig-Maximilians-University, Munich, Germany.,Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center Munich (BMC), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Veronika Müller
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center Munich (BMC), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stephan A Müller
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich and Neuroproteomics Unit, Technical University, Munich, Germany
| | - Stefan F Lichtenthaler
- Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE) Munich and Neuroproteomics Unit, Technical University, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Peter B Becker
- Division of Molecular Biology, Biomedical Center Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Johanna C Scheuermann
- Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center Munich (BMC), Ludwig-Maximilians-Universität München, Munich, Germany
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31
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Haws SA, Simandi Z, Barnett RJ, Phillips-Cremins JE. 3D genome, on repeat: Higher-order folding principles of the heterochromatinized repetitive genome. Cell 2022; 185:2690-2707. [PMID: 35868274 DOI: 10.1016/j.cell.2022.06.052] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 12/16/2022]
Abstract
Nearly half of the human genome is comprised of diverse repetitive sequences ranging from satellite repeats to retrotransposable elements. Such sequences are susceptible to stepwise expansions, duplications, inversions, and recombination events which can compromise genome function. In this review, we discuss the higher-order folding mechanisms of compartmentalization and loop extrusion and how they shape, and are shaped by, heterochromatin. Using primarily mammalian model systems, we contrast mechanisms governing H3K9me3-mediated heterochromatinization of the repetitive genome and highlight emerging links between repetitive elements and chromatin folding.
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Affiliation(s)
- Spencer A Haws
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zoltan Simandi
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - R Jordan Barnett
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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32
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Belmont AS. Nuclear Compartments: An Incomplete Primer to Nuclear Compartments, Bodies, and Genome Organization Relative to Nuclear Architecture. Cold Spring Harb Perspect Biol 2022; 14:a041268. [PMID: 34400557 PMCID: PMC9248822 DOI: 10.1101/cshperspect.a041268] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This work reviews nuclear compartments, defined broadly to include distinct nuclear structures, bodies, and chromosome domains. It first summarizes original cytological observations before comparing concepts of nuclear compartments emerging from microscopy versus genomic approaches and then introducing new multiplexed imaging approaches that promise in the future to meld both approaches. I discuss how previous models of radial distribution of chromosomes or the binary division of the genome into A and B compartments are now being refined by the recognition of more complex nuclear compartmentalization. The poorly understood question of how these nuclear compartments are established and maintained is then discussed, including through the modern perspective of phase separation, before moving on to address possible functions of nuclear compartments, using the possible role of nuclear speckles in modulating gene expression as an example. Finally, the review concludes with a discussion of future questions for this field.
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Affiliation(s)
- Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA
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33
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Mirny L, Dekker J. Mechanisms of Chromosome Folding and Nuclear Organization: Their Interplay and Open Questions. Cold Spring Harb Perspect Biol 2022; 14:a040147. [PMID: 34518339 PMCID: PMC9248823 DOI: 10.1101/cshperspect.a040147] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Microscopy and genomic approaches provide detailed descriptions of the three-dimensional folding of chromosomes and nuclear organization. The fundamental question is how activity of molecules at the nanometer scale can lead to complex and orchestrated spatial organization at the scale of chromosomes and the whole nucleus. At least three key mechanisms can bridge across scales: (1) tethering of specific loci to nuclear landmarks leads to massive reorganization of the nucleus; (2) spatial compartmentalization of chromatin, which is driven by molecular affinities, results in spatial isolation of active and inactive chromatin; and (3) loop extrusion activity of SMC (structural maintenance of chromosome) complexes can explain many features of interphase chromatin folding and underlies key phenomena during mitosis. Interestingly, many features of chromosome organization ultimately result from collective action and the interplay between these mechanisms, and are further modulated by transcription and topological constraints. Finally, we highlight some outstanding questions that are critical for our understanding of nuclear organization and function. We believe many of these questions can be answered in the coming years.
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Affiliation(s)
- Leonid Mirny
- Institute for Medical Engineering and Science, and Department of Physics, MIT, Cambridge, Massachusetts 02139, USA
| | - Job Dekker
- Howard Hughes Medical Institute, and Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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34
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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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35
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Reiff SB, Schroeder AJ, Kırlı K, Cosolo A, Bakker C, Mercado L, Lee S, Veit AD, Balashov AK, Vitzthum C, Ronchetti W, Pitman KM, Johnson J, Ehmsen SR, Kerpedjiev P, Abdennur N, Imakaev M, Öztürk SU, Çamoğlu U, Mirny LA, Gehlenborg N, Alver BH, Park PJ. The 4D Nucleome Data Portal as a resource for searching and visualizing curated nucleomics data. Nat Commun 2022; 13:2365. [PMID: 35501320 PMCID: PMC9061818 DOI: 10.1038/s41467-022-29697-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 03/28/2022] [Indexed: 01/03/2023] Open
Abstract
The 4D Nucleome (4DN) Network aims to elucidate the complex structure and organization of chromosomes in the nucleus and the impact of their disruption in disease biology. We present the 4DN Data Portal ( https://data.4dnucleome.org/ ), a repository for datasets generated in the 4DN network and relevant external datasets. Datasets were generated with a wide range of experiments, including chromosome conformation capture assays such as Hi-C and other innovative sequencing and microscopy-based assays probing chromosome architecture. All together, the 4DN data portal hosts more than 1800 experiment sets and 36000 files. Results of sequencing-based assays from different laboratories are uniformly processed and quality-controlled. The portal interface allows easy browsing, filtering, and bulk downloads, and the integrated HiGlass genome browser allows interactive visualization and comparison of multiple datasets. The 4DN data portal represents a primary resource for chromosome contact and other nuclear architecture data for the scientific community.
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Affiliation(s)
- Sarah B Reiff
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrew J Schroeder
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Koray Kırlı
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrea Cosolo
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Clara Bakker
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Luisa Mercado
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Soohyun Lee
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Alexander D Veit
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Alexander K Balashov
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Carl Vitzthum
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - William Ronchetti
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Kent M Pitman
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Jeremy Johnson
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Shannon R Ehmsen
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Peter Kerpedjiev
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Nezar Abdennur
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Maxim Imakaev
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Uğur Çamoğlu
- Karya SMD Software Solutions, İzmir, 35040, Turkey
| | - Leonid A Mirny
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nils Gehlenborg
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Burak H Alver
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA
| | - Peter J Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA, 02115, USA.
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36
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Melamed A, Fitzgerald TW, Wang Y, Ma J, Birney E, Bangham CRM. Selective clonal persistence of human retroviruses in vivo: Radial chromatin organization, integration site, and host transcription. SCIENCE ADVANCES 2022; 8:eabm6210. [PMID: 35486737 PMCID: PMC9054021 DOI: 10.1126/sciadv.abm6210] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
The human retroviruses HTLV-1 (human T cell leukemia virus type 1) and HIV-1 persist in vivo as a reservoir of latently infected T cell clones. It is poorly understood what determines which clones survive in the reservoir. We compared >160,000 HTLV-1 integration sites (>40,000 HIV-1 sites) from T cells isolated ex vivo from naturally infected individuals with >230,000 HTLV-1 integration sites (>65,000 HIV-1 sites) from in vitro infection to identify genomic features that determine selective clonal survival. Three statistically independent factors together explained >40% of the observed variance in HTLV-1 clonal survival in vivo: the radial intranuclear position of the provirus, its genomic distance from the centromere, and the intensity of local host genome transcription. The radial intranuclear position of the provirus and its distance from the centromere also explained ~7% of clonal persistence of HIV-1 in vivo. Selection for the intranuclear and intrachromosomal location of the provirus and host transcription intensity favors clonal persistence of human retroviruses in vivo.
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Affiliation(s)
- Anat Melamed
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, UK
| | | | - Yuchuan Wang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Jian Ma
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Ewan Birney
- European Bioinformatics Institute (EMBL-EBI), Cambridge, UK
| | - Charles R. M. Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, UK
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37
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Genome-wide maps of nucleolus interactions reveal distinct layers of repressive chromatin domains. Nat Commun 2022; 13:1483. [PMID: 35304483 PMCID: PMC8933459 DOI: 10.1038/s41467-022-29146-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 02/28/2022] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic chromosomes are folded into hierarchical domains, forming functional compartments. Nuclear periphery and nucleolus are two nuclear landmarks contributing to repressive chromosome architecture. However, while the role of nuclear lamina (NL) in genome organization has been well documented, the function of the nucleolus remains under-investigated due to the lack of methods for the identification of nucleolar associated domains (NADs). Here we have established DamID- and HiC-based methodologies to generate accurate genome-wide maps of NADs in embryonic stem cells (ESCs) and neural progenitor cells (NPCs), revealing layers of genome compartmentalization with distinct, repressive chromatin states based on the interaction with the nucleolus, NL, or both. NADs show higher H3K9me2 and lower H3K27me3 content than regions exclusively interacting with NL. Upon ESC differentiation into NPCs, chromosomes around the nucleolus acquire a more compact, rigid architecture with neural genes moving away from nucleoli and becoming unlocked for later activation. Further, histone modifications and the interaction strength within A and B compartments of NADs and LADs in ESCs set the choice to associate with NL or nucleoli upon dissociation from their respective compartments during differentiation. The methodologies here developed will make possible to include the nucleolar contribution in nuclear space and genome function in diverse biological systems.
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38
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Xie SQ, Leeke BJ, Whilding C, Wagner RT, Garcia-Llagostera F, Low Y, Chammas P, Cheung NTF, Dormann D, McManus MT, Percharde M. Nucleolar-based Dux repression is essential for embryonic two-cell stage exit. Genes Dev 2022; 36:331-347. [PMID: 35273077 PMCID: PMC8973846 DOI: 10.1101/gad.349172.121] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/17/2022] [Indexed: 12/14/2022]
Abstract
Upon fertilization, the mammalian embryo must switch from dependence on maternal transcripts to transcribing its own genome, and in mice this involves the transient up-regulation of MERVL transposons and MERVL-driven genes at the two-cell stage. The mechanisms and requirement for MERVL and two-cell (2C) gene up-regulation are poorly understood. Moreover, this MERVL-driven transcriptional program must be rapidly shut off to allow two-cell exit and developmental progression. Here, we report that robust ribosomal RNA (rRNA) synthesis and nucleolar maturation are essential for exit from the 2C state. 2C-like cells and two-cell embryos show similar immature nucleoli with altered structure and reduced rRNA output. We reveal that nucleolar disruption via blocking RNA polymerase I activity or preventing nucleolar phase separation enhances conversion to a 2C-like state in embryonic stem cells (ESCs) by detachment of the MERVL activator Dux from the nucleolar surface. In embryos, nucleolar disruption prevents proper nucleolar maturation and Dux silencing and leads to two- to four-cell arrest. Our findings reveal an intriguing link between rRNA synthesis, nucleolar maturation, and gene repression during early development.
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Affiliation(s)
- Sheila Q Xie
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Bryony J Leeke
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Chad Whilding
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Ryan T Wagner
- University of California at San Francisco, San Francisco, California 91413, USA
| | - Ferran Garcia-Llagostera
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - YiXuan Low
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Paul Chammas
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Nathan T-F Cheung
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Dirk Dormann
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
| | - Michael T McManus
- University of California at San Francisco, San Francisco, California 91413, USA
| | - Michelle Percharde
- MRC London Institute of Medical Sciences, London W12 0NN, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London W12 0NN, United Kingdom
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39
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Boninsegna L, Yildirim A, Zhan Y, Alber F. Integrative approaches in genome structure analysis. Structure 2022; 30:24-36. [PMID: 34963059 PMCID: PMC8959402 DOI: 10.1016/j.str.2021.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/13/2021] [Accepted: 12/01/2021] [Indexed: 12/17/2022]
Abstract
New technological advances in integrated imaging, sequencing-based assays, and computational analysis have revolutionized our view of genomes in terms of their structure and dynamics in space and time. These advances promise a deeper understanding of genome functions and mechanistic insights into how the nucleus is spatially organized and functions. These wide arrays of complementary data provide an opportunity to produce quantitative integrative models of nuclear organization. In this article, we highlight recent key developments and discuss the outlook for these fields.
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Affiliation(s)
- Lorenzo Boninsegna
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Asli Yildirim
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Yuxiang Zhan
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Frank Alber
- Institute for Quantitative and Computational Biosciences, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
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40
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Bridger JM, Pereira RT, Pina C, Tosi S, Lewis A. Alterations to Genome Organisation in Stem Cells, Their Differentiation and Associated Diseases. Results Probl Cell Differ 2022; 70:71-102. [PMID: 36348105 DOI: 10.1007/978-3-031-06573-6_3] [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] [Indexed: 06/16/2023]
Abstract
The organisation of the genome in its home, the cell nucleus, is reliant on a number of different aspects to establish, maintain and alter its functional non-random positioning. The genome is dispersed throughout a cell nucleus in specific chromosome territories which are further divided into topologically associated domains (TADs), where regions of the genome from different and the same chromosomes come together. This organisation is both controlled by DNA and chromatin epigenetic modification and the association of the genome with nuclear structures such as the nuclear lamina, the nucleolus and nuclear bodies and speckles. Indeed, sequences that are associated with the first two structures mentioned are termed lamina-associated domains (LADs) and nucleolar-associated domains (NADs), respectively. The modifications and nuclear structures that regulate genome function are altered through a cell's life from stem cell to differentiated cell through to reversible quiescence and irreversible senescence, and hence impacting on genome organisation, altering it to silence specific genes and permit others to be expressed in a controlled way in different cell types and cell cycle statuses. The structures and enzymes and thus the organisation of the genome can also be deleteriously affected, leading to disease and/or premature ageing.
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Affiliation(s)
- Joanna M Bridger
- Division of Biosciences, Department of Life Sciences, Centre for Genome Engineering and Maintenance (cenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK.
| | - Rita Torres Pereira
- Division of Biosciences, Department of Life Sciences, Centre for Genome Engineering and Maintenance (cenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Cristina Pina
- Division of Biosciences, Department of Life Sciences, Centre for Genome Engineering and Maintenance (cenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Sabrina Tosi
- Division of Biosciences, Department of Life Sciences, Centre for Genome Engineering and Maintenance (cenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Annabelle Lewis
- Division of Biosciences, Department of Life Sciences, Centre for Genome Engineering and Maintenance (cenGEM), College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
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41
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Vertii A. Stress as a Chromatin Landscape Architect. Front Cell Dev Biol 2021; 9:790138. [PMID: 34970548 PMCID: PMC8712864 DOI: 10.3389/fcell.2021.790138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/19/2021] [Indexed: 11/16/2022] Open
Abstract
The exponential development of methods investigating different levels of spatial genome organization leads to the appreciation of the chromatin landscape's contribution to gene regulation and cell fate. Multiple levels of 3D chromatin organization include chromatin loops and topologically associated domains, followed by euchromatin and heterochromatin compartments, chromatin domains associated with nuclear bodies, and culminate with the chromosome territories. 3D chromatin architecture is exposed to multiple factors such as cell division and stress, including but not limited to mechanical, inflammatory, and environmental challenges. How exactly the stress exposure shapes the chromatin landscape is a new and intriguing area of research. In this mini-review, the developments that motivate the exploration of this field are discussed.
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Affiliation(s)
- Anastassiia Vertii
- Department of Molecular, Cellular and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, United States
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42
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Abstract
Nuclear bodies are membraneless condensates that may form via liquid-liquid phase separation. The viscoelastic chromatin network could impact their stability and may hold the key for understanding experimental observations that defy predictions of classical theories. However, quantitative studies on the role of the chromatin network in phase separation have remained challenging. Using a diploid human genome model parameterized with chromosome conformation capture (Hi-C) data, we study the thermodynamics and kinetics of nucleoli formation. Dynamical simulations predict the formation of multiple droplets for nucleolar particles that experience specific interactions with nucleolus-associated domains (NADs). Coarsening dynamics, surface tension, and coalescence kinetics of the simulated droplets are all in quantitative agreement with experimental measurements for nucleoli. Free energy calculations further support that a two-droplet state, often observed for nucleoli in somatic cells, is metastable and separated from the single-droplet state with an entropic barrier. Our study suggests that nucleoli-chromatin interactions facilitate droplets' nucleation but hinder their coarsening due to the coupled motion between droplets and the chromatin network: as droplets coalesce, the chromatin network becomes increasingly constrained. Therefore, the chromatin network supports a nucleation and arrest mechanism to stabilize the multi-droplet state for nucleoli and possibly for other nuclear bodies.
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43
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Park TL, Lee Y, Cho WK. Visualization of chromatin higher-order structures and dynamics in live cells. BMB Rep 2021. [PMID: 34488934 PMCID: PMC8560465 DOI: 10.5483/bmbrep.2021.54.10.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromatin has highly organized structures in the nucleus, and these higher-order structures are proposed to regulate gene activities and cellular processes. Sequencing-based techniques, such as Hi-C, and fluorescent in situ hybridization (FISH) have revealed a spatial segregation of active and inactive compartments of chromatin, as well as the non-random positioning of chromosomes in the nucleus, respectively. However, regardless of their efficiency in capturing target genomic sites, these techniques are limited to fixed cells. Since chromatin has dynamic structures, live cell imaging techniques are highlighted for their ability to detect conformational changes in chromatin at a specific time point, or to track various arrangements of chromatin through long-term imaging. Given that the imaging approaches to study live cells are dramatically advanced, we recapitulate methods that are widely used to visualize the dynamics of higher-order chromatin structures.
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Affiliation(s)
- Tae Lim Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - YigJi Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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44
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Trigiante G, Blanes Ruiz N, Cerase A. Emerging Roles of Repetitive and Repeat-Containing RNA in Nuclear and Chromatin Organization and Gene Expression. Front Cell Dev Biol 2021; 9:735527. [PMID: 34722514 PMCID: PMC8552494 DOI: 10.3389/fcell.2021.735527] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/09/2021] [Indexed: 12/14/2022] Open
Abstract
Genomic repeats have been intensely studied as regulatory elements controlling gene transcription, splicing and genome architecture. Our understanding of the role of the repetitive RNA such as the RNA coming from genomic repeats, or repetitive sequences embedded in mRNA/lncRNAs, in nuclear and cellular functions is instead still limited. In this review we discuss evidence supporting the multifaceted roles of repetitive RNA and RNA binding proteins in nuclear organization, gene regulation, and in the formation of dynamic membrane-less aggregates. We hope that our review will further stimulate research in the consolidating field of repetitive RNA biology.
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Affiliation(s)
| | | | - Andrea Cerase
- Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Blizard Institute, Queen Mary University of London, London, United Kingdom
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45
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Nuclear Dynamics and Chromatin Structure: Implications for Pancreatic Cancer. Cells 2021; 10:cells10102624. [PMID: 34685604 PMCID: PMC8534098 DOI: 10.3390/cells10102624] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 12/14/2022] Open
Abstract
Changes in nuclear shape have been extensively associated with the dynamics and functionality of cancer cells. In most normal cells, nuclei have a regular ellipsoid shape and minimal variation in nuclear size; however, an irregular nuclear contour and abnormal nuclear size is often observed in cancer, including pancreatic cancer. Furthermore, alterations in nuclear morphology have become the 'gold standard' for tumor staging and grading. Beyond the utility of altered nuclear morphology as a diagnostic tool in cancer, the implications of altered nuclear structure for the biology and behavior of cancer cells are profound as changes in nuclear morphology could impact cellular responses to physical strain, adaptation during migration, chromatin organization, and gene expression. Here, we aim to highlight and discuss the factors that regulate nuclear dynamics and their implications for pancreatic cancer biology.
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46
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Park TL, Lee Y, Cho WK. Visualization of chromatin higher-order structures and dynamics in live cells. BMB Rep 2021; 54:489-496. [PMID: 34488934 PMCID: PMC8560465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/09/2021] [Accepted: 08/29/2021] [Indexed: 04/05/2024] Open
Abstract
Chromatin has highly organized structures in the nucleus, and these higher-order structures are proposed to regulate gene activities and cellular processes. Sequencing-based techniques, such as Hi-C, and fluorescent in situ hybridization (FISH) have revealed a spatial segregation of active and inactive compartments of chromatin, as well as the non-random positioning of chromosomes in the nucleus, respectively. However, regardless of their efficiency in capturing target genomic sites, these techniques are limited to fixed cells. Since chromatin has dynamic structures, live cell imaging techniques are highlighted for their ability to detect conformational changes in chromatin at a specific time point, or to track various arrangements of chromatin through long-term imaging. Given that the imaging approaches to study live cells are dramatically advanced, we recapitulate methods that are widely used to visualize the dynamics of higher-order chromatin structures. [BMB Reports 2021; 54(10): 489-496].
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Affiliation(s)
- Tae Lim Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - YigJi Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
- KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
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47
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Abstract
Immediately following the discovery of the structure of DNA and the semi-conservative replication of the parental DNA sequence into two new DNA strands, it became apparent that DNA replication is organized in a temporal and spatial fashion during the S phase of the cell cycle, correlated with the large-scale organization of chromatin in the nucleus. After many decades of limited progress, technological advances in genomics, genome engineering, and imaging have finally positioned the field to tackle mechanisms underpinning the temporal and spatial regulation of DNA replication and the causal relationships between DNA replication and other features of large-scale chromosome structure and function. In this review, we discuss these major recent discoveries as well as expectations for the coming decade.
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Affiliation(s)
- Athanasios E Vouzas
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
| | - David M Gilbert
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA
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Erenpreisa J, Krigerts J, Salmina K, Gerashchenko BI, Freivalds T, Kurg R, Winter R, Krufczik M, Zayakin P, Hausmann M, Giuliani A. Heterochromatin Networks: Topology, Dynamics, and Function (a Working Hypothesis). Cells 2021; 10:1582. [PMID: 34201566 PMCID: PMC8304199 DOI: 10.3390/cells10071582] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 12/21/2022] Open
Abstract
Open systems can only exist by self-organization as pulsing structures exchanging matter and energy with the outer world. This review is an attempt to reveal the organizational principles of the heterochromatin supra-intra-chromosomal network in terms of nonlinear thermodynamics. The accessibility of the linear information of the genetic code is regulated by constitutive heterochromatin (CHR) creating the positional information in a system of coordinates. These features include scale-free splitting-fusing of CHR with the boundary constraints of the nucleolus and nuclear envelope. The analysis of both the literature and our own data suggests a radial-concentric network as the main structural organization principle of CHR regulating transcriptional pulsing. The dynamic CHR network is likely created together with nucleolus-associated chromatin domains, while the alveoli of this network, including springy splicing speckles, are the pulsing transcription hubs. CHR contributes to this regulation due to the silencing position variegation effect, stickiness, and flexible rigidity determined by the positioning of nucleosomes. The whole system acts in concert with the elastic nuclear actomyosin network which also emerges by self-organization during the transcriptional pulsing process. We hypothesize that the the transcriptional pulsing, in turn, adjusts its frequency/amplitudes specified by topologically associating domains to the replication timing code that determines epigenetic differentiation memory.
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Affiliation(s)
- Jekaterina Erenpreisa
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Jekabs Krigerts
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Kristine Salmina
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Bogdan I. Gerashchenko
- R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, National Academy of Sciences of Ukraine, 03022 Kyiv, Ukraine;
| | - Talivaldis Freivalds
- Institute of Cardiology and Regenerative Medicine, University of Latvia, LV-1004 Riga, Latvia;
| | - Reet Kurg
- Institute of Technology, University of Tartu, 50411 Tartu, Estonia;
| | - Ruth Winter
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Matthias Krufczik
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Pawel Zayakin
- Latvian Biomedicine Research and Study Centre, LV-1067 Riga, Latvia; (J.K.); (K.S.); (P.Z.)
| | - Michael Hausmann
- Kirchhoff Institute for Physics, Heidelberg University, 69120 Heidelberg, Germany; (R.W.); (M.K.); (M.H.)
| | - Alessandro Giuliani
- Istituto Superiore di Sanita Environment and Health Department, 00161 Roma, Italy
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The Ribosomal Gene Loci-The Power behind the Throne. Genes (Basel) 2021; 12:genes12050763. [PMID: 34069807 PMCID: PMC8157237 DOI: 10.3390/genes12050763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Nucleoli form around actively transcribed ribosomal RNA (rRNA) genes (rDNA), and the morphology and location of nucleolus-associated genomic domains (NADs) are linked to the RNA Polymerase I (Pol I) transcription status. The number of rDNA repeats (and the proportion of actively transcribed rRNA genes) is variable between cell types, individuals and disease state. Substantial changes in nucleolar morphology and size accompanied by concomitant changes in the Pol I transcription rate have long been documented during normal cell cycle progression, development and malignant transformation. This demonstrates how dynamic the nucleolar structure can be. Here, we will discuss how the structure of the rDNA loci, the nucleolus and the rate of Pol I transcription are important for dynamic regulation of global gene expression and genome stability, e.g., through the modulation of long-range genomic interactions with the suppressive NAD environment. These observations support an emerging paradigm whereby the rDNA repeats and the nucleolus play a key regulatory role in cellular homeostasis during normal development as well as disease, independent of their role in determining ribosome capacity and cellular growth rates.
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Hydroxyurea and Caffeine Impact pRb-like Protein-Dependent Chromatin Architecture Profiles in Interphase Cells of Vicia faba. Int J Mol Sci 2021; 22:ijms22094572. [PMID: 33925461 PMCID: PMC8123844 DOI: 10.3390/ijms22094572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/06/2021] [Accepted: 04/23/2021] [Indexed: 01/04/2023] Open
Abstract
The survival of cells depends on their ability to replicate correctly genetic material. Cells exposed to replication stress can experience a number of problems that may lead to deregulated proliferation, the development of cancer, and/or programmed cell death. In this article, we have induced prolonged replication arrest via hydroxyurea (HU) treatment and also premature chromosome condensation (PCC) by co-treatment with HU and caffeine (CF) in the root meristem cells of Vicia faba. We have analyzed the changes in the activities of retinoblastoma-like protein (RbS807/811ph). Results obtained from the immunocytochemical detection of RbS807/811ph allowed us to distinguish five unique activity profiles of pRb. We have also performed detailed 3D modeling using Blender 2.9.1., based on the original data and some final conclusions. 3D models helped us to visualize better the events occurring within the nuclei and acted as a high-resolution aid for presenting the results. We have found that, despite the decrease in pRb activity, its activity profiles were mostly intact and clearly recognizable, with some local alterations that may correspond to the increased demand in transcriptional activity. Our findings suggest that Vicia faba’s ability to withstand harsh environments may come from its well-developed and highly effective response to replication stress.
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