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González-Arzola K. The nucleolus: Coordinating stress response and genomic stability. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2024; 1867:195029. [PMID: 38642633 DOI: 10.1016/j.bbagrm.2024.195029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
The perception that the nucleoli are merely the organelles where ribosome biogenesis occurs is challenged. Only around 30 % of nucleolar proteins are solely involved in producing ribosomes. Instead, the nucleolus plays a critical role in controlling protein trafficking during stress and, according to its dynamic nature, undergoes continuous protein exchange with nucleoplasm under various cellular stressors. Hence, the concept of nucleolar stress has evolved as cellular insults that disrupt the structure and function of the nucleolus. Considering the emerging role of this organelle in DNA repair and the fact that rDNAs are the most fragile genomic loci, therapies targeting the nucleoli are increasingly being developed. Besides, drugs that target ribosome synthesis and induce nucleolar stress can be used in cancer therapy. In contrast, agents that regulate nucleolar activity may be a potential treatment for neurodegeneration caused by abnormal protein accumulation in the nucleolus. Here, I explore the roles of nucleoli beyond their ribosomal functions, highlighting the factors triggering nucleolar stress and their impact on genomic stability.
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Affiliation(s)
- Katiuska González-Arzola
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía, Universidad Pablo de Olavide, 41092 Seville, Spain; Departamento de Bioquímica Vegetal y Biología Molecular, Universidad de Sevilla, 41012 Seville, Spain.
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2
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Chakraborty S, Mishra J, Roy A, Niharika, Manna S, Baral T, Nandi P, Patra S, Patra SK. Liquid-liquid phase separation in subcellular assemblages and signaling pathways: Chromatin modifications induced gene regulation for cellular physiology and functions including carcinogenesis. Biochimie 2024; 223:74-97. [PMID: 38723938 DOI: 10.1016/j.biochi.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/08/2024] [Accepted: 05/04/2024] [Indexed: 05/24/2024]
Abstract
Liquid-liquid phase separation (LLPS) describes many biochemical processes, including hydrogel formation, in the integrity of macromolecular assemblages and existence of membraneless organelles, including ribosome, nucleolus, nuclear speckles, paraspeckles, promyelocytic leukemia (PML) bodies, Cajal bodies (all exert crucial roles in cellular physiology), and evidence are emerging day by day. Also, phase separation is well documented in generation of plasma membrane subdomains and interplay between membranous and membraneless organelles. Intrinsically disordered regions (IDRs) of biopolymers/proteins are the most critical sticking regions that aggravate the formation of such condensates. Remarkably, phase separated condensates are also involved in epigenetic regulation of gene expression, chromatin remodeling, and heterochromatinization. Epigenetic marks on DNA and histones cooperate with RNA-binding proteins through their IDRs to trigger LLPS for facilitating transcription. How phase separation coalesces mutant oncoproteins, orchestrate tumor suppressor genes expression, and facilitated cancer-associated signaling pathways are unravelling. That autophagosome formation and DYRK3-mediated cancer stem cell modification also depend on phase separation is deciphered in part. In view of this, and to linchpin insight into the subcellular membraneless organelle assembly, gene activation and biological reactions catalyzed by enzymes, and the downstream physiological functions, and how all these events are precisely facilitated by LLPS inducing organelle function, epigenetic modulation of gene expression in this scenario, and how it goes awry in cancer progression are summarized and presented in this article.
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Affiliation(s)
- Subhajit Chakraborty
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Jagdish Mishra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Niharika
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Soumen Manna
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Piyasa Nandi
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Subhajit Patra
- Department of Chemical Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India.
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3
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Fu B, Ma H, Liu D. Essential roles of the nucleolus during early embryonic development: a regulatory hub for chromatin organization. Open Biol 2024; 14:230358. [PMID: 38689555 PMCID: PMC11065130 DOI: 10.1098/rsob.230358] [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: 10/02/2023] [Revised: 12/26/2023] [Accepted: 03/15/2024] [Indexed: 05/02/2024] Open
Abstract
The nucleolus is the most prominent liquid droplet-like membrane-less organelle in mammalian cells. Unlike the nucleolus in terminally differentiated somatic cells, those in totipotent cells, such as murine zygotes or two-cell embryos, have a unique nucleolar structure known as nucleolus precursor bodies (NPBs). Previously, it was widely accepted that NPBs in zygotes are simply passive repositories of materials that will be gradually used to construct a fully functional nucleolus after zygotic genome activation (ZGA). However, recent research studies have challenged this simplistic view and demonstrated that functions of the NPBs go beyond ribosome biogenesis. In this review, we provide a snapshot of the functions of NPBs in zygotes and early two-cell embryos in mice. We propose that these membrane-less organelles function as a regulatory hub for chromatin organization. On the one hand, NPBs provide the structural platform for centric and pericentric chromatin remodelling. On the other hand, the dynamic changes in nucleolar structure control the release of the pioneer factors (i.e. double homeobox (Dux)). It appears that during transition from totipotency to pluripotency, decline of totipotency and initiation of fully functional nucleolus formation are not independent events but are interconnected. Consequently, it is reasonable to hypothesize that dissecting more unknown functions of NPBs may shed more light on the enigmas of early embryonic development and may ultimately provide novel approaches to improve reprogramming efficiency.
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Affiliation(s)
- Bo Fu
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
| | - Hong Ma
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
| | - Di Liu
- Institute of Animal Husbandry, HeiLongJiang Academy of
Agricultural Sciences, Harbin150086, People's Republic of China
- Key Laboratory of Combining Farming and Animal Husbandry,
Ministry of Agriculture and Rural Affairs, Harbin150086, People's Republic of China
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4
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Gholamalamdari O, van Schaik T, Wang Y, Kumar P, Zhang L, Zhang Y, Hernandez Gonzalez GA, 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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Salinas-Pena M, Rebollo E, Jordan A. Imaging analysis of six human histone H1 variants reveals universal enrichment of H1.2, H1.3, and H1.5 at the nuclear periphery and nucleolar H1X presence. eLife 2024; 12:RP91306. [PMID: 38530350 DOI: 10.7554/elife.91306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024] Open
Abstract
Histone H1 participates in chromatin condensation and regulates nuclear processes. Human somatic cells may contain up to seven histone H1 variants, although their functional heterogeneity is not fully understood. Here, we have profiled the differential nuclear distribution of the somatic H1 repertoire in human cells through imaging techniques including super-resolution microscopy. H1 variants exhibit characteristic distribution patterns in both interphase and mitosis. H1.2, H1.3, and H1.5 are universally enriched at the nuclear periphery in all cell lines analyzed and co-localize with compacted DNA. H1.0 shows a less pronounced peripheral localization, with apparent variability among different cell lines. On the other hand, H1.4 and H1X are distributed throughout the nucleus, being H1X universally enriched in high-GC regions and abundant in the nucleoli. Interestingly, H1.4 and H1.0 show a more peripheral distribution in cell lines lacking H1.3 and H1.5. The differential distribution patterns of H1 suggest specific functionalities in organizing lamina-associated domains or nucleolar activity, which is further supported by a distinct response of H1X or phosphorylated H1.4 to the inhibition of ribosomal DNA transcription. Moreover, H1 variants depletion affects chromatin structure in a variant-specific manner. Concretely, H1.2 knock-down, either alone or combined, triggers a global chromatin decompaction. Overall, imaging has allowed us to distinguish H1 variants distribution beyond the segregation in two groups denoted by previous ChIP-Seq determinations. Our results support H1 variants heterogeneity and suggest that variant-specific functionality can be shared between different cell types.
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Affiliation(s)
| | - Elena Rebollo
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Albert Jordan
- Molecular Biology Institute of Barcelona (IBMB-CSIC), Barcelona, Spain
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6
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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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7
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Hao Q, Liu M, Daulatabad SV, Gaffari S, Song YJ, Srivastava R, Bhaskar S, Moitra A, Mangan H, Tseng E, Gilmore RB, Frier SM, Chen X, Wang C, Huang S, Chamberlain S, Jin H, Korlach J, McStay B, Sinha S, Janga SC, Prasanth SG, Prasanth KV. Monoallelically expressed noncoding RNAs form nucleolar territories on NOR-containing chromosomes and regulate rRNA expression. eLife 2024; 13:e80684. [PMID: 38240312 PMCID: PMC10852677 DOI: 10.7554/elife.80684] [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: 05/31/2022] [Accepted: 01/18/2024] [Indexed: 02/07/2024] Open
Abstract
Out of the several hundred copies of rRNA genes arranged in the nucleolar organizing regions (NOR) of the five human acrocentric chromosomes, ~50% remain transcriptionally inactive. NOR-associated sequences and epigenetic modifications contribute to the differential expression of rRNAs. However, the mechanism(s) controlling the dosage of active versus inactive rRNA genes within each NOR in mammals is yet to be determined. We have discovered a family of ncRNAs, SNULs (Single NUcleolus Localized RNA), which form constrained sub-nucleolar territories on individual NORs and influence rRNA expression. Individual members of the SNULs monoallelically associate with specific NOR-containing chromosomes. SNULs share sequence similarity to pre-rRNA and localize in the sub-nucleolar compartment with pre-rRNA. Finally, SNULs control rRNA expression by influencing pre-rRNA sorting to the DFC compartment and pre-rRNA processing. Our study discovered a novel class of ncRNAs influencing rRNA expression by forming constrained nucleolar territories on individual NORs.
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Affiliation(s)
- Qinyu Hao
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Minxue Liu
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Swapna Vidhur Daulatabad
- Department of BioHealth Informatics, School of Informatics and Computing, IUPUIIndianapolisUnited States
| | - Saba Gaffari
- Department of Computer Science, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - You Jin Song
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Rajneesh Srivastava
- Department of BioHealth Informatics, School of Informatics and Computing, IUPUIIndianapolisUnited States
| | - Shivang Bhaskar
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Anurupa Moitra
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Hazel Mangan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | | | - Rachel B Gilmore
- Department of Genetics and Genome Sciences, University of Connecticut School of MedicineFarmingtonUnited States
| | | | - Xin Chen
- Department of Biophysics and Quantitative Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Chengliang Wang
- Department of Biochemistry, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Sui Huang
- Department of Cell and Molecular Biology, Northwestern UniversityChicagoUnited States
| | - Stormy Chamberlain
- Department of Genetics and Genome Sciences, University of Connecticut School of MedicineFarmingtonUnited States
| | - Hong Jin
- Department of Biophysics and Quantitative Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
- Department of Biochemistry, University of Illinois at Urbana-ChampaignUrbanaUnited States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | | | - Brian McStay
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Saurabh Sinha
- Department of Computer Science, University of Illinois at Urbana-ChampaignUrbanaUnited States
- Department of Biomedical Engineering, Georgia TechAtlantaUnited States
| | - Sarath Chandra Janga
- Department of BioHealth Informatics, School of Informatics and Computing, IUPUIIndianapolisUnited States
| | - Supriya G Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
- Cancer Center at Illinois, University of Illinois at Urbana-ChampaignUrbanaUnited States
| | - Kannanganattu V Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-ChampaignUrbanaUnited States
- Cancer Center at Illinois, University of Illinois at Urbana-ChampaignUrbanaUnited States
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8
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Böğürcü-Seidel N, Ritschel N, Acker T, Németh A. Beyond ribosome biogenesis: noncoding nucleolar RNAs in physiology and tumor biology. Nucleus 2023; 14:2274655. [PMID: 37906621 PMCID: PMC10730139 DOI: 10.1080/19491034.2023.2274655] [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: 07/31/2023] [Accepted: 10/19/2023] [Indexed: 11/02/2023] Open
Abstract
The nucleolus, the largest subcompartment of the nucleus, stands out from the nucleoplasm due to its exceptionally high local RNA and low DNA concentrations. Within this central hub of nuclear RNA metabolism, ribosome biogenesis is the most prominent ribonucleoprotein (RNP) biogenesis process, critically determining the structure and function of the nucleolus. However, recent studies have shed light on other roles of the nucleolus, exploring the interplay with various noncoding RNAs that are not directly involved in ribosome synthesis. This review focuses on this intriguing topic and summarizes the techniques to study and the latest findings on nucleolar long noncoding RNAs (lncRNAs) as well as microRNAs (miRNAs) in the context of nucleolus biology beyond ribosome biogenesis. We particularly focus on the multifaceted roles of the nucleolus and noncoding RNAs in physiology and tumor biology.
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Affiliation(s)
| | - Nadja Ritschel
- Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Till Acker
- Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Attila Németh
- Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
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9
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Pezic D, Weeks S, Varsally W, Dewari PS, Pollard S, Branco MR, Hadjur S. The N-terminus of Stag1 is required to repress the 2C program by maintaining rRNA expression and nucleolar integrity. Stem Cell Reports 2023; 18:2154-2173. [PMID: 37802073 PMCID: PMC10679541 DOI: 10.1016/j.stemcr.2023.09.004] [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: 01/30/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023] Open
Abstract
Our understanding of how STAG proteins contribute to cell identity and disease have largely been studied from the perspective of chromosome topology and protein-coding gene expression. Here, we show that STAG1 is the dominant paralog in mouse embryonic stem cells (mESCs) and is required for pluripotency. mESCs express a wide diversity of naturally occurring Stag1 isoforms, resulting in complex regulation of both the levels of STAG paralogs and the proportion of their unique terminal ends. Skewing the balance of these isoforms impacts cell identity. We define a novel role for STAG1, in particular its N-terminus, in regulating repeat expression, nucleolar integrity, and repression of the two-cell (2C) state to maintain mESC identity. Our results move beyond protein-coding gene regulation via chromatin loops to new roles for STAG1 in nucleolar structure and function, and offer fresh perspectives on how STAG proteins, known to be cancer targets, contribute to cell identity and disease.
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Affiliation(s)
- Dubravka Pezic
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Samuel Weeks
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Wazeer Varsally
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK
| | - Pooran S Dewari
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Steven Pollard
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, Cancer Research UK Scotland Centre, Edinburgh, UK
| | - Miguel R Branco
- Blizard Institute, Faculty of Medicine and Dentistry, QMUL, London, UK
| | - Suzana Hadjur
- Department of Cancer Biology, Cancer Institute, University College London, 72 Huntley Street, London, UK.
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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] [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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Shevelyov YY. Interactions of Chromatin with the Nuclear Lamina and Nuclear Pore Complexes. Int J Mol Sci 2023; 24:15771. [PMID: 37958755 PMCID: PMC10649103 DOI: 10.3390/ijms242115771] [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: 10/06/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
Heterochromatin and euchromatin form different spatial compartments in the interphase nucleus, with heterochromatin being localized mainly at the nuclear periphery. The mechanisms responsible for peripheral localization of heterochromatin are still not fully understood. The nuclear lamina and nuclear pore complexes were obvious candidates for the role of heterochromatin binders. This review is focused on recent studies showing that heterochromatin interactions with the nuclear lamina and nuclear pore complexes maintain its peripheral localization. Differences in chromatin interactions with the nuclear envelope in cell populations and in individual cells are also discussed.
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Affiliation(s)
- Yuri Y Shevelyov
- Laboratory of Analysis of Gene Regulation, National Research Centre "Kurchatov Institute", Kurchatov Sq. 2, 123182 Moscow, Russia
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12
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Daiß JL, Griesenbeck J, Tschochner H, Engel C. Synthesis of the ribosomal RNA precursor in human cells: mechanisms, factors and regulation. Biol Chem 2023; 404:1003-1023. [PMID: 37454246 DOI: 10.1515/hsz-2023-0214] [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: 05/12/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023]
Abstract
The ribosomal RNA precursor (pre-rRNA) comprises three of the four ribosomal RNAs and is synthesized by RNA polymerase (Pol) I. Here, we describe the mechanisms of Pol I transcription in human cells with a focus on recent insights gained from structure-function analyses. The comparison of Pol I-specific structural and functional features with those of other Pols and with the excessively studied yeast system distinguishes organism-specific from general traits. We explain the organization of the genomic rDNA loci in human cells, describe the Pol I transcription cycle regarding structural changes in the enzyme and the roles of human Pol I subunits, and depict human rDNA transcription factors and their function on a mechanistic level. We disentangle information gained by direct investigation from what had apparently been deduced from studies of the yeast enzymes. Finally, we provide information about how Pol I mutations may contribute to developmental diseases, and why Pol I is a target for new cancer treatment strategies, since increased rRNA synthesis was correlated with rapidly expanding cell populations.
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Affiliation(s)
- Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Joachim Griesenbeck
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Herbert Tschochner
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, D-93053 Regensburg, Germany
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13
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Kovač A, Miskey C, Ivics Z. Sleeping Beauty Transposon Insertions into Nucleolar DNA by an Engineered Transposase Localized in the Nucleolus. Int J Mol Sci 2023; 24:14978. [PMID: 37834425 PMCID: PMC10573994 DOI: 10.3390/ijms241914978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Transposons are nature's gene delivery vehicles that can be harnessed for experimental and therapeutic purposes. The Sleeping Beauty (SB) transposon shows efficient transposition and long-term transgene expression in human cells, and is currently under clinical development for gene therapy. SB transposition occurs into the human genome in a random manner, which carries a risk of potential genotoxic effects associated with transposon integration. Here, we evaluated an experimental strategy to manipulate SB's target site distribution by preferentially compartmentalizing the SB transposase to the nucleolus, which contains repetitive ribosomal RNA (rRNA) genes. We generated a fusion protein composed of the nucleolar protein nucleophosmin (B23) and the SB100X transposase, which was found to retain almost full transposition activity as compared to unfused transposase and to be predominantly localized to nucleoli in transfected human cells. Analysis of transposon integration sites generated by B23-SB100X revealed a significant enrichment into the p-arms of chromosomes containing nucleolus organizing regions (NORs), with preferential integration into the p13 and p11.2 cytobands directly neighboring the NORs. This bias in the integration pattern was accompanied by an enrichment of insertions into nucleolus-associated chromatin domains (NADs) at the periphery of nucleolar DNA and into lamina-associated domains (LADs). Finally, sub-nuclear targeting of the transposase resulted in preferential integration into chromosomal domains associated with the Upstream Binding Transcription Factor (UBTF) that plays a critical role in the transcription of 47S rDNA gene repeats of the NORs by RNA Pol I. Future modifications of this technology may allow the development of methods for specific gene insertion for precision genetic engineering.
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Affiliation(s)
| | | | - Zoltán Ivics
- Transposition and Genome Engineering, Research Centre of the Division of Hematology, Gene and Cell Therapy, Paul Ehrlich Institute, Paul Ehrlich Str. 51–59, D-63225 Langen, Germany; (A.K.); (C.M.)
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14
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Rajshekar S, Adame-Arana O, Bajpai G, Lin K, Colmenares S, Safran S, Karpen GH. Affinity hierarchies and amphiphilic proteins underlie the co-assembly of nucleolar and heterochromatin condensates. RESEARCH SQUARE 2023:rs.3.rs-3385692. [PMID: 37841837 PMCID: PMC10571612 DOI: 10.21203/rs.3.rs-3385692/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Nucleoli are surrounded by Pericentromeric Heterochromatin (PCH), reflecting a close spatial association between the two largest biomolecular condensates in eukaryotic nuclei. This nuclear organizational feature is highly conserved and is disrupted in diseased states like senescence, however, the mechanisms driving PCH-nucleolar association are unclear. High-resolution live imaging during early Drosophila development revealed a highly dynamic process in which PCH and nucleolar formation is coordinated and interdependent. When nucleolus assembly was eliminated by deleting the ribosomal RNA genes (rDNA), PCH showed increased compaction and subsequent reorganization to a shell-like structure. In addition, in embryos lacking rDNA, some nucleolar proteins were redistributed into new bodies or 'neocondensates,' including enrichment in the core of the PCH shell. These observations, combined with physical modeling and simulations, suggested that nucleolar-PCH associations are mediated by a hierarchy of affinities between PCH, nucleoli, and 'amphiphilic' protein(s) that interact with both nucleolar and PCH components. This result was validated by demonstrating that the depletion of one candidate amphiphile, the nucleolar protein Pitchoune, significantly reduced PCH-nucleolar associations. Together, these results unveil a dynamic program for establishing nucleolar-PCH associations during animal development, demonstrate that nucleoli are required for normal PCH organization, and identify Pitchoune as an amphiphilic molecular link that promotes PCH-nucleolar associations. Finally, we propose that disrupting affinity hierarchies between interacting condensates can liberate molecules to form neocondensates or other aberrant structures that could contribute to cellular disease phenotypes.
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Affiliation(s)
- Srivarsha Rajshekar
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Omar Adame-Arana
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Gaurav Bajpai
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Kyle Lin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Serafin Colmenares
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Samuel Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
- Division of Biological Sciences and the Environment, Lawrence Berkeley National Laboratory, Berkeley, USA
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15
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Rajshekar S, Adame-Arana O, Bajpai G, Lin K, Colmenares S, Safran S, Karpen GH. Affinity hierarchies and amphiphilic proteins underlie the co-assembly of nucleolar and heterochromatin condensates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.06.547894. [PMID: 37808710 PMCID: PMC10557603 DOI: 10.1101/2023.07.06.547894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Nucleoli are surrounded by Pericentromeric Heterochromatin (PCH), reflecting a close spatial association between the two largest biomolecular condensates in eukaryotic nuclei. This nuclear organizational feature is highly conserved and is disrupted in diseased states like senescence, however, the mechanisms driving PCH-nucleolar association are unclear. High-resolution live imaging during early Drosophila development revealed a highly dynamic process in which PCH and nucleolar formation is coordinated and interdependent. When nucleolus assembly was eliminated by deleting the ribosomal RNA genes (rDNA), PCH showed increased compaction and subsequent reorganization to a shell-like structure. In addition, in embryos lacking rDNA, some nucleolar proteins were redistributed into new bodies or 'neocondensates,' including enrichment in the core of the PCH shell. These observations, combined with physical modeling and simulations, suggested that nucleolar-PCH associations are mediated by a hierarchy of affinities between PCH, nucleoli, and 'amphiphilic' protein(s) that interact with both nucleolar and PCH components. This result was validated by demonstrating that the depletion of one candidate amphiphile, the nucleolar protein Pitchoune, significantly reduced PCH-nucleolar associations. Together, these results unveil a dynamic program for establishing nucleolar-PCH associations during animal development, demonstrate that nucleoli are required for normal PCH organization, and identify Pitchoune as an amphiphilic molecular link that promotes PCH-nucleolar associations. Finally, we propose that disrupting affinity hierarchies between interacting condensates can liberate molecules to form neocondensates or other aberrant structures that could contribute to cellular disease phenotypes.
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Affiliation(s)
- Srivarsha Rajshekar
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Omar Adame-Arana
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Gaurav Bajpai
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Kyle Lin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Serafin Colmenares
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
| | - Samuel Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, USA
- Division of Biological Sciences and the Environment, Lawrence Berkeley National Laboratory, Berkeley, USA
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16
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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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17
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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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18
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Wu S, Chen J, Teo BHD, Wee SYK, Wong MHM, Cui J, Chen J, Leong KP, Lu J. The axis of complement C1 and nucleolus in antinuclear autoimmunity. Front Immunol 2023; 14:1196544. [PMID: 37359557 PMCID: PMC10288996 DOI: 10.3389/fimmu.2023.1196544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/19/2023] [Indexed: 06/28/2023] Open
Abstract
Antinuclear autoantibodies (ANA) are heterogeneous self-reactive antibodies that target the chromatin network, the speckled, the nucleoli, and other nuclear regions. The immunological aberration for ANA production remains partially understood, but ANA are known to be pathogenic, especially, in systemic lupus erythematosus (SLE). Most SLE patients exhibit a highly polygenic disease involving multiple organs, but in rare complement C1q, C1r, or C1s deficiencies, the disease can become largely monogenic. Increasing evidence point to intrinsic autoimmunogenicity of the nuclei. Necrotic cells release fragmented chromatins as nucleosomes and the alarmin HMGB1 is associated with the nucleosomes to activate TLRs and confer anti-chromatin autoimmunogenecity. In speckled regions, the major ANA targets Sm/RNP and SSA/Ro contain snRNAs that confer autoimmunogenecity to Sm/RNP and SSA/Ro antigens. Recently, three GAR/RGG-containing alarmins have been identified in the nucleolus that helps explain its high autoimmunogenicity. Interestingly, C1q binds to the nucleoli exposed by necrotic cells to cause protease C1r and C1s activation. C1s cleaves HMGB1 to inactive its alarmin activity. C1 proteases also degrade many nucleolar autoantigens including nucleolin, a major GAR/RGG-containing autoantigen and alarmin. It appears that the different nuclear regions are intrinsically autoimmunogenic by containing autoantigens and alarmins. However, the extracellular complement C1 complex function to dampen nuclear autoimmunogenecity by degrading these nuclear proteins.
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Affiliation(s)
- Shan Wu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Junjie Chen
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Boon Heng Dennis Teo
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Seng Yin Kelly Wee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ming Hui Millie Wong
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jianzhou Cui
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jinmiao Chen
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - Khai Pang Leong
- Department of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, Singapore, Singapore
| | - Jinhua Lu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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19
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Li S, Shen X. Long interspersed nuclear element 1 and B1/Alu repeats blueprint genome compartmentalization. Curr Opin Genet Dev 2023; 80:102049. [PMID: 37229928 DOI: 10.1016/j.gde.2023.102049] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 05/27/2023]
Abstract
The organization of the genome into euchromatin and heterochromatin has been known for almost 100 years [1]. More than 50% of mammalian genomes contain repetitive sequences [2,3]. Recently, a functional link between the genome and its folding has been identified [4,5]. Homotypic clustering of long interspersed nuclear element 1 (LINE1 or L1) and B1/Alu retrotransposons forms grossly exclusive nuclear domains that characterize and predict heterochromatin and euchromatin, respectively. The spatial segregation of L1 and B1/Alu-rich compartments is conserved in mammalian cells and can be rebuilt during the cell cycle and established de novo in early embryogenesis. Inhibition of L1 RNA drastically weakened homotypic repeat contacts and compartmental segregation, indicating that L1 plays a more significant role than just being a compartmental marker. This simple and inclusive genetic coding model of L1 and B1/Alu in shaping the macroscopic structure of the genome provides a plausible explanation for the remarkable conservation and robustness of its folding in mammalian cells. It also proposes a conserved core structure on which subsequent dynamic regulation takes place.
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Affiliation(s)
- Siyang Li
- Department of Basic Medical Sciences, School of Medicine, Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaohua Shen
- Department of Basic Medical Sciences, School of Medicine, Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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20
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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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21
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Di Nunzio F, Uversky VN, Mouland AJ. Biomolecular condensates: insights into early and late steps of the HIV-1 replication cycle. Retrovirology 2023; 20:4. [PMID: 37029379 PMCID: PMC10081342 DOI: 10.1186/s12977-023-00619-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/16/2023] [Indexed: 04/09/2023] Open
Abstract
A rapidly evolving understanding of phase separation in the biological and physical sciences has led to the redefining of virus-engineered replication compartments in many viruses with RNA genomes. Condensation of viral, host and genomic and subgenomic RNAs can take place to evade the innate immunity response and to help viral replication. Divergent viruses prompt liquid-liquid phase separation (LLPS) to invade the host cell. During HIV replication there are several steps involving LLPS. In this review, we characterize the ability of individual viral and host partners that assemble into biomolecular condensates (BMCs). Of note, bioinformatic analyses predict models of phase separation in line with several published observations. Importantly, viral BMCs contribute to function in key steps retroviral replication. For example, reverse transcription takes place within nuclear BMCs, called HIV-MLOs while during late replication steps, retroviral nucleocapsid acts as a driver or scaffold to recruit client viral components to aid the assembly of progeny virions. Overall, LLPS during viral infections represents a newly described biological event now appreciated in the virology field, that can also be considered as an alternative pharmacological target to current drug therapies especially when viruses become resistant to antiviral treatment.
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Affiliation(s)
- Francesca Di Nunzio
- Advanced Molecular Virology Unit, Department of Virology, Institut Pasteur, Université Paris Cité, 75015, Paris, France
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Andrew J Mouland
- Lady Davis Institute at the Jewish General Hospital, Montréal, QC, H3T 1E2, Canada.
- Department of Microbiology and Immunology, McGill University, Montréal, QC, H3A 2B4, Canada.
- Department of Medicine, McGill University, Montréal, QC, H4A 3J1, Canada.
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22
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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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23
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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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24
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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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25
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Martin L, Neguembor MV, Cosma MP. Women’s contribution in understanding how topoisomerases, supercoiling, and transcription control genome organization. Front Mol Biosci 2023; 10:1155825. [PMID: 37051322 PMCID: PMC10083264 DOI: 10.3389/fmolb.2023.1155825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/15/2023] [Indexed: 03/28/2023] Open
Abstract
One of the biggest paradoxes in biology is that human genome is roughly 2 m long, while the nucleus containing it is almost one million times smaller. To fit into the nucleus, DNA twists, bends and folds into several hierarchical levels of compaction. Still, DNA has to maintain a high degree of accessibility to be readily replicated and transcribed by proteins. How compaction and accessibility co-exist functionally in human cells is still a matter of debate. Here, we discuss how the torsional stress of the DNA helix acts as a buffer, regulating both chromatin compaction and accessibility. We will focus on chromatin supercoiling and on the emerging role of topoisomerases as pivotal regulators of genome organization. We will mainly highlight the major breakthrough studies led by women, with the intention of celebrating the work of this group that remains a minority within the scientific community.
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Affiliation(s)
- Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Technical Contact, Guangzhou, China
- *Correspondence: Maria Victoria Neguembor, ; Maria Pia Cosma,
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- ICREA, Barcelona, Spain
- Medical Research Institute, Guangdong Provincial People’s Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Lead Contact, Guangzhou, China
- *Correspondence: Maria Victoria Neguembor, ; Maria Pia Cosma,
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26
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Decle-Carrasco S, Rodríguez-Piña AL, Rodríguez-Zapata LC, Castano E. Current research on viral proteins that interact with fibrillarin. Mol Biol Rep 2023; 50:4631-4643. [PMID: 36928641 PMCID: PMC10018631 DOI: 10.1007/s11033-023-08343-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/15/2023] [Indexed: 03/18/2023]
Abstract
The nucleolus is a multifunctional nuclear domain primarily dedicated to ribosome biogenesis. Certain viruses developed strategies to manipulate host nucleolar proteins to facilitate their replication by modulating ribosomal RNA (rRNA) processing. This association interferes with nucleolar functions resulting in overactivation or arrest of ribosome biogenesis, induction or inhibition of apoptosis, and affecting stress response. The nucleolar protein fibrillarin (FBL) is an important target of some plant and animal viruses. FBL is an essential and highly conserved S-adenosyl methionine (SAM) dependent methyltransferase, capable of rRNA degradation by its intrinsically disordered region (IDR), the glycine/arginine-rich (GAR) domain. It forms a ribonucleoprotein complex that directs 2'-O-methylations in more than 100 sites of pre-rRNAs. It is involved in multiple cellular processes, including initiation of transcription, oncogenesis, and apoptosis, among others. The interaction with animal viruses, including human viruses, triggered its redistribution to the nucleoplasm and cytoplasm, interfering with its role in pre-rRNA processing. Viral-encoded proteins with IDRs as nucleocapsids, matrix, Tat protein, and even a viral snoRNA, can associate with FBL, forcing the nucleolar protein to undergo atypical functions. Here we review the molecular mechanisms employed by animal and human viruses to usurp FBL functions and the effect on cellular processes, particularly in ribosome biogenesis.
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Affiliation(s)
- Stefano Decle-Carrasco
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Alma Laura Rodríguez-Piña
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Luis Carlos Rodríguez-Zapata
- Unidad de Biotecnología. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México
| | - Enrique Castano
- Unidad de Bioquímica y Biología Molecular de Plantas. Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatán, México.
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27
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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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28
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Spracklin G, Abdennur N, Imakaev M, Chowdhury N, Pradhan S, Mirny LA, Dekker J. Diverse silent chromatin states modulate genome compartmentalization and loop extrusion barriers. Nat Struct Mol Biol 2023; 30:38-51. [PMID: 36550219 PMCID: PMC9851908 DOI: 10.1038/s41594-022-00892-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 11/01/2022] [Indexed: 12/24/2022]
Abstract
The relationships between chromosomal compartmentalization, chromatin state and function are poorly understood. Here by profiling long-range contact frequencies in HCT116 colon cancer cells, we distinguish three silent chromatin states, comprising two types of heterochromatin and a state enriched for H3K9me2 and H2A.Z that exhibits neutral three-dimensional interaction preferences and which, to our knowledge, has not previously been characterized. We find that heterochromatin marked by H3K9me3, HP1α and HP1β correlates with strong compartmentalization. We demonstrate that disruption of DNA methyltransferase activity greatly remodels genome compartmentalization whereby domains lose H3K9me3-HP1α/β binding and acquire the neutrally interacting state while retaining late replication timing. Furthermore, we show that H3K9me3-HP1α/β heterochromatin is permissive to loop extrusion by cohesin but refractory to CTCF binding. Together, our work reveals a dynamic structural and organizational diversity of the silent portion of the genome and establishes connections between the regulation of chromatin state and chromosome organization, including an interplay between DNA methylation, compartmentalization and loop extrusion.
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Affiliation(s)
- George Spracklin
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA.
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Nezar Abdennur
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Maxim Imakaev
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Neil Chowdhury
- Program for Research in Mathematics, Engineering and Science for High School Students (PRIMES), MIT, Cambridge, MA, USA
| | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Job Dekker
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA.
- Howard Hughes Medical Institute, Chevy Chase, USA.
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29
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Fu B, Ma H, Liu D. 2-Cell-like Cells: An Avenue for Improving SCNT Efficiency. Biomolecules 2022; 12:1611. [PMID: 36358959 PMCID: PMC9687756 DOI: 10.3390/biom12111611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/23/2022] [Accepted: 10/26/2022] [Indexed: 03/25/2024] Open
Abstract
After fertilization, the zygote genome undergoes dramatic structural reorganization to ensure the establishment of totipotency, and then the totipotent potential of the zygote or 2-cell-stage embryo progressively declines. However, cellular potency is not always a one-way street. Specifically, a small number of embryonic stem cells (ESCs) occasionally overcome epigenetic barriers and transiently convert to a totipotent status. Despite the significant potential of the somatic cell nuclear transfer (SCNT) technique, the establishment of totipotency is often deficient in cloned embryos. Because of this phenomenon, the question arises as to whether strategies attempting to induce 2-cell-like cells (2CLCs) can provide practical applications, such as reprogramming of somatic cell nuclei. Inspired by strategies that convert ESCs into 2CLCs, we hypothesized that there will be a similar pathway by which cloned embryos can establish totipotent status after SCNT. In this review, we provide a snapshot of the practical strategies utilized to induce 2CLCs during investigations of the development of cloned embryos. The 2CLCs have similar transcriptome and chromatin features to that of 2-cell-stage embryos, and we propose that 2CLCs, already a valuable in vitro model for dissecting totipotency, will provide new opportunities to improve SCNT efficiency.
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Affiliation(s)
- Bo Fu
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
| | - Hong Ma
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
| | - Di Liu
- Institute of Animal Husbandry, Heilongjiang Academy of Agricultural Sciences, Harbin 150086, China
- Key Laboratory of Combining Farming and Animal Husbandry, Ministry of Agriculture and Rural Affairs, Harbin 150086, China
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30
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Podgornaya OI. Nuclear organization by satellite DNA, SAF-A/hnRNPU and matrix attachment regions. Semin Cell Dev Biol 2022; 128:61-68. [PMID: 35484025 DOI: 10.1016/j.semcdb.2022.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 12/15/2022]
Abstract
The need of large-scale chromatin organization in the nucleus has become more and more appreciated. The higher order nuclear organization ultimately regulate a plethora of biological processes including transcription, DNA replication, and DNA repair. In this context, it is of critical importance to understand the mechanisms that allow higher order nuclear organization. Scaffold Attachment Factor A (SAF-A/hnRNPU), which was originally identified as the component of nuclear matrix, has emerged as an important regulator of higher order nuclear organization. It is shown that SAF-A/hnRNPU binds to tandem repeats (TRs) and scaffold/matrix attachment regions (S/MAR) in a sequence-non-specific, but structure-specific manner (e.g. DNA curvature). Recent studies showed that SAF-A interacts with chromatin-associated RNAs (caRNAs) to regulate interphase chromatin structures in a transcription-dependent manner. It is proposed that SAF-A/hnRNPU and caRNAs form a dynamic, transcriptionally responsive chromatin mesh that organizes chromatin in a large scale. The common structural features of S/MAR and pericentromeric (periCEN) TR promotes SAF-A-mediated association with each other. Collectively a model is presented wherein SAF-A/hnRNPU and periCEN TR are the key players in large-scale nuclear organization that supports general transcription.
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Affiliation(s)
- O I Podgornaya
- Institute of Cytology RAS, St. Petersburg State University, Russia.
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31
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Faber GP, Nadav-Eliyahu S, Shav-Tal Y. Nuclear speckles - a driving force in gene expression. J Cell Sci 2022; 135:275909. [PMID: 35788677 DOI: 10.1242/jcs.259594] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nuclear speckles are dynamic membraneless bodies located in the cell nucleus. They harbor RNAs and proteins, many of which are splicing factors, that together display complex biophysical properties dictating nuclear speckle formation and maintenance. Although these nuclear bodies were discovered decades ago, only recently has in-depth genomic analysis begun to unravel their essential functions in modulation of gene activity. Major advancements in genomic mapping techniques combined with microscopy approaches have enabled insights into the roles nuclear speckles may play in enhancing gene expression, and how gene positioning to specific nuclear landmarks can regulate gene expression and RNA processing. Some studies have drawn a link between nuclear speckles and disease. Certain maladies either involve nuclear speckles directly or dictate the localization and reorganization of many nuclear speckle factors. This is most striking during viral infection, as viruses alter the entire nuclear architecture and highjack host machinery. As discussed in this Review, nuclear speckles represent a fascinating target of study not only to reveal the links between gene positioning, genome subcompartments and gene activity, but also as a potential target for therapeutics.
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Affiliation(s)
- Gabriel P Faber
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Shani Nadav-Eliyahu
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
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32
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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: 14] [Impact Index Per Article: 7.0] [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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33
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Tan SYX, Zhang J, Tee WW. Epigenetic Regulation of Inflammatory Signaling and Inflammation-Induced Cancer. Front Cell Dev Biol 2022; 10:931493. [PMID: 35757000 PMCID: PMC9213816 DOI: 10.3389/fcell.2022.931493] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/23/2022] [Indexed: 01/10/2023] Open
Abstract
Epigenetics comprise a diverse array of reversible and dynamic modifications to the cell’s genome without implicating any DNA sequence alterations. Both the external environment surrounding the organism, as well as the internal microenvironment of cells and tissues, contribute to these epigenetic processes that play critical roles in cell fate specification and organismal development. On the other hand, dysregulation of epigenetic activities can initiate and sustain carcinogenesis, which is often augmented by inflammation. Chronic inflammation, one of the major hallmarks of cancer, stems from proinflammatory cytokines that are secreted by tumor and tumor-associated cells in the tumor microenvironment. At the same time, inflammatory signaling can establish positive and negative feedback circuits with chromatin to modulate changes in the global epigenetic landscape. In this review, we provide an in-depth discussion of the interconnected crosstalk between epigenetics and inflammation, specifically how epigenetic mechanisms at different hierarchical levels of the genome control inflammatory gene transcription, which in turn enact changes within the cell’s epigenomic profile, especially in the context of inflammation-induced cancer.
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Affiliation(s)
- Shawn Ying Xuan Tan
- Chromatin Dynamics and Disease Epigenetics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
| | - Jieqiong Zhang
- Chromatin Dynamics and Disease Epigenetics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Wee-Wei Tee
- Chromatin Dynamics and Disease Epigenetics Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,NUS Centre for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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34
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Boldyreva LV, Andreyeva EN, Pindyurin AV. Position Effect Variegation: Role of the Local Chromatin Context in Gene Expression Regulation. Mol Biol 2022. [DOI: 10.1134/s0026893322030049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Abstract
One of the most fundamental questions in developmental biology is how one fertilized cell can give rise to a fully mature organism and how gene regulation governs this process. Precise spatiotemporal gene expression is required for development and is believed to be achieved through a complex interplay of sequence-specific information, epigenetic modifications, trans-acting factors, and chromatin folding. Here we review the role of chromatin folding during development, the mechanisms governing 3D genome organization, and how it is established in the embryo. Furthermore, we discuss recent advances and debated questions regarding the contribution of the 3D genome to gene regulation during organogenesis. Finally, we describe the mechanisms that can reshape the 3D genome, including disease-causing structural variations and the emerging view that transposable elements contribute to chromatin organization.
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Affiliation(s)
- Juliane Glaser
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Stefan Mundlos
- RG Development and Disease, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
- Institute for Medical and Human Genetics, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany
- Charité - Universitätsmedizin Berlin, BCRT - Berlin Institute of Health Center for Regenerative Therapies, 10178 Berlin, Germany
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36
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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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37
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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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38
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Matsumori H, Watanabe K, Tachiwana H, Fujita T, Ito Y, Tokunaga M, Sakata-Sogawa K, Osakada H, Haraguchi T, Awazu A, Ochiai H, Sakata Y, Ochiai K, Toki T, Ito E, Goldberg IG, Tokunaga K, Nakao M, Saitoh N. Ribosomal protein L5 facilitates rDNA-bundled condensate and nucleolar assembly. Life Sci Alliance 2022; 5:5/7/e202101045. [PMID: 35321919 PMCID: PMC8942980 DOI: 10.26508/lsa.202101045] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022] Open
Abstract
High content image analysis, single molecule tracking, modeling, and DBA patient analysis revealed that ribosomal protein L5 facilitates rDNA-bundled condensate and nucleolar assembly. The nucleolus is the site of ribosome assembly and formed through liquid–liquid phase separation. Multiple ribosomal DNA (rDNA) arrays are bundled in the nucleolus, but the underlying mechanism and significance are unknown. In the present study, we performed high-content screening followed by image profiling with the wndchrm machine learning algorithm. We revealed that cells lacking a specific 60S ribosomal protein set exhibited common nucleolar disintegration. The depletion of RPL5 (also known as uL18), the liquid–liquid phase separation facilitator, was most effective, and resulted in an enlarged and un-separated sub-nucleolar compartment. Single-molecule tracking analysis revealed less-constrained mobility of its components. rDNA arrays were also unbundled. These results were recapitulated by a coarse-grained molecular dynamics model. Transcription and processing of ribosomal RNA were repressed in these aberrant nucleoli. Consistently, the nucleoli were disordered in peripheral blood cells from a Diamond–Blackfan anemia patient harboring a heterozygous, large deletion in RPL5. Our combinatorial analyses newly define the role of RPL5 in rDNA array bundling and the biophysical properties of the nucleolus, which may contribute to the etiology of ribosomopathy.
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Affiliation(s)
- Haruka Matsumori
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Kenji Watanabe
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Hiroaki Tachiwana
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Tomoko Fujita
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yuma Ito
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Makio Tokunaga
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Kumiko Sakata-Sogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroko Osakada
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan.,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Akinori Awazu
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.,Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Higashi-Hiroshima, Japan
| | - Hiroshi Ochiai
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Yuka Sakata
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | | | - Tsutomu Toki
- Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Etsuro Ito
- Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Ilya G Goldberg
- Image Informatics and Computational Biology Unit, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Kazuaki Tokunaga
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Mitsuyoshi Nakao
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Noriko Saitoh
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
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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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40
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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: 5] [Impact Index Per Article: 2.5] [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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Abstract
In eukaryotic cells, protein and RNA factors involved in genome activities like transcription, RNA processing, DNA replication, and repair accumulate in self-organizing membraneless chromatin subcompartments. These structures contribute to efficiently conduct chromatin-mediated reactions and to establish specific cellular programs. However, the underlying mechanisms for their formation are only partly understood. Recent studies invoke liquid-liquid phase separation (LLPS) of proteins and RNAs in the establishment of chromatin activity patterns. At the same time, the folding of chromatin in the nucleus can drive genome partitioning into spatially distinct domains. Here, the interplay between chromatin organization, chromatin binding, and LLPS is discussed by comparing and contrasting three prototypical chromatin subcompartments: the nucleolus, clusters of active RNA polymerase II, and pericentric heterochromatin domains. It is discussed how the different ways of chromatin compartmentalization are linked to transcription regulation, the targeting of soluble factors to certain parts of the genome, and to disease-causing genetic aberrations.
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Affiliation(s)
- Karsten Rippe
- Division of Chromatin Networks, German Cancer Research Center (DKFZ) and Bioquant, 69120 Heidelberg, Germany
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42
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Kumar S, Kaur S, Seem K, Kumar S, Mohapatra T. Understanding 3D Genome Organization and Its Effect on Transcriptional Gene Regulation Under Environmental Stress in Plant: A Chromatin Perspective. Front Cell Dev Biol 2021; 9:774719. [PMID: 34957106 PMCID: PMC8692796 DOI: 10.3389/fcell.2021.774719] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 11/23/2021] [Indexed: 01/17/2023] Open
Abstract
The genome of a eukaryotic organism is comprised of a supra-molecular complex of chromatin fibers and intricately folded three-dimensional (3D) structures. Chromosomal interactions and topological changes in response to the developmental and/or environmental stimuli affect gene expression. Chromatin architecture plays important roles in DNA replication, gene expression, and genome integrity. Higher-order chromatin organizations like chromosome territories (CTs), A/B compartments, topologically associating domains (TADs), and chromatin loops vary among cells, tissues, and species depending on the developmental stage and/or environmental conditions (4D genomics). Every chromosome occupies a separate territory in the interphase nucleus and forms the top layer of hierarchical structure (CTs) in most of the eukaryotes. While the A and B compartments are associated with active (euchromatic) and inactive (heterochromatic) chromatin, respectively, having well-defined genomic/epigenomic features, TADs are the structural units of chromatin. Chromatin architecture like TADs as well as the local interactions between promoter and regulatory elements correlates with the chromatin activity, which alters during environmental stresses due to relocalization of the architectural proteins. Moreover, chromatin looping brings the gene and regulatory elements in close proximity for interactions. The intricate relationship between nucleotide sequence and chromatin architecture requires a more comprehensive understanding to unravel the genome organization and genetic plasticity. During the last decade, advances in chromatin conformation capture techniques for unravelling 3D genome organizations have improved our understanding of genome biology. However, the recent advances, such as Hi-C and ChIA-PET, have substantially increased the resolution, throughput as well our interest in analysing genome organizations. The present review provides an overview of the historical and contemporary perspectives of chromosome conformation capture technologies, their applications in functional genomics, and the constraints in predicting 3D genome organization. We also discuss the future perspectives of understanding high-order chromatin organizations in deciphering transcriptional regulation of gene expression under environmental stress (4D genomics). These might help design the climate-smart crop to meet the ever-growing demands of food, feed, and fodder.
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Affiliation(s)
- Suresh Kumar
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Simardeep Kaur
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Karishma Seem
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India
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43
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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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44
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Bire S, Dusserre Y, Bigot Y, Mermod N. PiggyBac transposase and transposon derivatives for gene transfer targeting the ribosomal DNA loci of CHO cells. J Biotechnol 2021; 341:103-112. [PMID: 34560160 DOI: 10.1016/j.jbiotec.2021.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/24/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022]
Abstract
Integrative non-viral vectors such as transposons engineered to mediate targeted gene transfer into safe harbor sites in the genome may be a promising approach for the production of therapeutic proteins or for gene therapy in an efficient and secure way. In this context, we designed and evaluated two strategies for targeting the nuclear ribosomal DNA (rDNA) loci. One approach relied on the co-location of the transposase and transposon near transcriptionally active rDNA copies using a nucleolar localization signal (NoLS). Another one consisted of targeting the 18S-coding region in the rDNA loci using a NoLS-FokI-dCas9 endonuclease to perform targeted transgene knock-in. We show that integration into the rDNA of Chinese hamster ovary (CHO) cells can be achieved at a high frequency using the piggyBac transposon system, indicating that the rDNA is highly accessible for transposition. Consistently, rDNA-targeted transposition events were most frequently obtained when both the piggyBac transposon DNA and the transposase were nucleoli-targeted, yielding cells displaying stable and homogeneous expression of the transgene. This approach thus provides an alternative strategy to improve targeted transgene delivery and protein expression using CHO cells.
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Affiliation(s)
- Solenne Bire
- Institute of Biotechnology and Department of Fundamental Microbiology, Center for Biotechnology UNIL-EPFL, University of Lausanne, Lausanne, Switzerland
| | - Yves Dusserre
- Institute of Biotechnology and Department of Fundamental Microbiology, Center for Biotechnology UNIL-EPFL, University of Lausanne, Lausanne, Switzerland
| | - Yves Bigot
- UMR INRAE 0085, CNRS 7247, Physiologie de la Reproduction et des Comportements, Centre INRAE Val de Loire, 37380 Nouzilly, France
| | - Nicolas Mermod
- Institute of Biotechnology and Department of Fundamental Microbiology, Center for Biotechnology UNIL-EPFL, University of Lausanne, Lausanne, Switzerland.
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45
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Yu H, Sun Z, Tan T, Pan H, Zhao J, Zhang L, Chen J, Lei A, Zhu Y, Chen L, Xu Y, Liu Y, Chen M, Sheng J, Xu Z, Qian P, Li C, Gao S, Daley GQ, Zhang J. rRNA biogenesis regulates mouse 2C-like state by 3D structure reorganization of peri-nucleolar heterochromatin. Nat Commun 2021; 12:6365. [PMID: 34753899 PMCID: PMC8578659 DOI: 10.1038/s41467-021-26576-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 10/06/2021] [Indexed: 11/09/2022] Open
Abstract
The nucleolus is the organelle for ribosome biogenesis and sensing various types of stress. However, its role in regulating stem cell fate remains unclear. Here, we present evidence that nucleolar stress induced by interfering rRNA biogenesis can drive the 2-cell stage embryo-like (2C-like) program and induce an expanded 2C-like cell population in mouse embryonic stem (mES) cells. Mechanistically, nucleolar integrity maintains normal liquid-liquid phase separation (LLPS) of the nucleolus and the formation of peri-nucleolar heterochromatin (PNH). Upon defects in rRNA biogenesis, the natural state of nucleolus LLPS is disrupted, causing dissociation of the NCL/TRIM28 complex from PNH and changes in epigenetic state and reorganization of the 3D structure of PNH, which leads to release of Dux, a 2C program transcription factor, from PNH to activate a 2C-like program. Correspondingly, embryos with rRNA biogenesis defect are unable to develop from 2-cell (2C) to 4-cell embryos, with delayed repression of 2C/ERV genes and a transcriptome skewed toward earlier cleavage embryo signatures. Our results highlight that rRNA-mediated nucleolar integrity and 3D structure reshaping of the PNH compartment regulates the fate transition of mES cells to 2C-like cells, and that rRNA biogenesis is a critical regulator during the 2-cell to 4-cell transition of murine pre-implantation embryo development.
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Affiliation(s)
- Hua Yu
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Zhen Sun
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Tianyu Tan
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Hongru Pan
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Jing Zhao
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Ling Zhang
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Jiayu Chen
- Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Anhua Lei
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Yuqing Zhu
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Lang Chen
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Yuyan Xu
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China
| | - Yaxin Liu
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
| | - Ming Chen
- College of Life Sciences, Zhejiang University, 310058, Hangzhou, China
| | - Jinghao Sheng
- Institute of Environmental Medicine, and Cancer Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China
| | - Zhengping Xu
- Institute of Environmental Medicine, and Cancer Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310058, Hangzhou, China
| | - Pengxu Qian
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China
| | - Cheng Li
- Center for Bioinformatics, School of Life Sciences, Center for Statistical Science, Peking University, 100871, Beijing, China
| | - Shaorong Gao
- Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - George Q Daley
- Stem Cell Transplantation Program, Division of Pediatric Hematology Oncology, Boston Children's Hospital, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Jin Zhang
- Center of Stem Cell and Regenerative Medicine, Department of Basic Medical Sciences, and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, 310003, Hangzhou, China.
- Zhejiang Laboratory for Systems & Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, 311121, Hangzhou, China.
- Institute of Hematology, Zhejiang University, 310058, Hangzhou, China.
- Center of Gene/Cell Engineering and Genome Medicine, 310058, Hangzhou, Zhejiang, China.
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46
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Yap K, Chung TH, Makeyev EV. Hybridization-proximity labeling reveals spatially ordered interactions of nuclear RNA compartments. Mol Cell 2021; 82:463-478.e11. [PMID: 34741808 PMCID: PMC8791277 DOI: 10.1016/j.molcel.2021.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022]
Abstract
The ability of RNAs to form specific contacts with other macromolecules provides an important mechanism for subcellular compartmentalization. Here we describe a suite of hybridization-proximity (HyPro) labeling technologies for unbiased discovery of proteins (HyPro-MS) and transcripts (HyPro-seq) associated with RNAs of interest in genetically unperturbed cells. As a proof of principle, we show that HyPro-MS and HyPro-seq can identify both known and previously unexplored spatial neighbors of the noncoding RNAs 45S, NEAT1, and PNCTR expressed at markedly different levels. Notably, HyPro-seq uncovers an extensive repertoire of incompletely processed, adenosine-to-inosine-edited transcripts accumulating at the interface between their encoding chromosomal regions and the NEAT1-containing paraspeckle compartment. At least some of these targets require NEAT1 for their optimal expression. Overall, this study provides a versatile toolkit for dissecting RNA interactomes in diverse biomedical contexts and expands our understanding of the functional architecture of the mammalian nucleus. HyPro labeling uncovers interactors and spatial neighbors of RNAs of interest Protein and RNA partners are identified by mass spectrometry and deep sequencing No genetic modifications are required, allowing wider biomedical use Interactomes of RNA-containing nuclear bodies are mapped as a proof of principle
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Affiliation(s)
- Karen Yap
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Tek Hong Chung
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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47
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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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48
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Mohanta TK, Mishra AK, Al-Harrasi A. The 3D Genome: From Structure to Function. Int J Mol Sci 2021; 22:11585. [PMID: 34769016 PMCID: PMC8584255 DOI: 10.3390/ijms222111585] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 01/09/2023] Open
Abstract
The genome is the most functional part of a cell, and genomic contents are organized in a compact three-dimensional (3D) structure. The genome contains millions of nucleotide bases organized in its proper frame. Rapid development in genome sequencing and advanced microscopy techniques have enabled us to understand the 3D spatial organization of the genome. Chromosome capture methods using a ligation approach and the visualization tool of a 3D genome browser have facilitated detailed exploration of the genome. Topologically associated domains (TADs), lamin-associated domains, CCCTC-binding factor domains, cohesin, and chromatin structures are the prominent identified components that encode the 3D structure of the genome. Although TADs are the major contributors to 3D genome organization, they are absent in Arabidopsis. However, a few research groups have reported the presence of TAD-like structures in the plant kingdom.
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Affiliation(s)
- Tapan Kumar Mohanta
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Oman
| | - Awdhesh Kumar Mishra
- Department of Biotechnology, Yeungnam University, Gyeongsan 38541, Gyeongsangbuk-do, Korea; or
| | - Ahmed Al-Harrasi
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Oman
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49
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Zell J, Duskova K, Chouh L, Bossaert M, Chéron N, Granzhan A, Britton S, Monchaud D. Dual targeting of higher-order DNA structures by azacryptands induces DNA junction-mediated DNA damage in cancer cells. Nucleic Acids Res 2021; 49:10275-10288. [PMID: 34551430 PMCID: PMC8501980 DOI: 10.1093/nar/gkab796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/16/2021] [Accepted: 09/01/2021] [Indexed: 12/11/2022] Open
Abstract
DNA is intrinsically dynamic and folds transiently into alternative higher-order structures such as G-quadruplexes (G4s) and three-way DNA junctions (TWJs). G4s and TWJs can be stabilised by small molecules (ligands) that have high chemotherapeutic potential, either as standalone DNA damaging agents or combined in synthetic lethality strategies. While previous approaches have claimed to use ligands that specifically target either G4s or TWJs, we report here on a new approach in which ligands targeting both TWJs and G4s in vitro demonstrate cellular effects distinct from that of G4 ligands, and attributable to TWJ targeting. The DNA binding modes of these new, dual TWJ-/G4-ligands were studied by a panel of in vitro methods and theoretical simulations, and their cellular properties by extensive cell-based assays. We show here that cytotoxic activity of TWJ-/G4-ligands is mitigated by the DNA damage response (DDR) and DNA topoisomerase 2 (TOP2), making them different from typical G4-ligands, and implying a pivotal role of TWJs in cells. We designed and used a clickable ligand, TrisNP-α, to provide unique insights into the TWJ landscape in cells and its modulation upon co-treatments. This wealth of data was exploited to design an efficient synthetic lethality strategy combining dual ligands with clinically relevant DDR inhibitors.
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Affiliation(s)
- Joanna Zell
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB), CNRS UMR 6302, UBFC Dijon, 21078 Dijon, France
| | - Katerina Duskova
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB), CNRS UMR 6302, UBFC Dijon, 21078 Dijon, France
| | - Leïla Chouh
- Institut Curie, CNRS UMR 9187, INSERM U1196, PSL Research University, 91405 Orsay, France
- Université Paris Saclay, CNRS UMR 9187, INSERM U1196, 91405 Orsay, France
| | - Madeleine Bossaert
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS UMR 5089, Université de Toulouse, UPS, Équipe labellisée la Ligue Contre le Cancer, 31077 Toulouse, France
| | - Nicolas Chéron
- Pasteur, Département de chimie, École Normale Supérieure (ENS), CNRS UMR8640, PSL Research University, Sorbonne Université, 75005 Paris, France
| | - Anton Granzhan
- Institut Curie, CNRS UMR 9187, INSERM U1196, PSL Research University, 91405 Orsay, France
- Université Paris Saclay, CNRS UMR 9187, INSERM U1196, 91405 Orsay, France
| | - Sébastien Britton
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS UMR 5089, Université de Toulouse, UPS, Équipe labellisée la Ligue Contre le Cancer, 31077 Toulouse, France
| | - David Monchaud
- Institut de Chimie Moléculaire de l’Université de Bourgogne (ICMUB), CNRS UMR 6302, UBFC Dijon, 21078 Dijon, France
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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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