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Panichnantakul P, Aguilar LC, Daynard E, Guest M, Peters C, Vogel J, Oeffinger M. Protein UFMylation regulates early events during ribosomal DNA-damage response. Cell Rep 2024; 43:114738. [PMID: 39277864 DOI: 10.1016/j.celrep.2024.114738] [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: 02/25/2024] [Revised: 07/03/2024] [Accepted: 08/23/2024] [Indexed: 09/17/2024] Open
Abstract
The highly repetitive and transcriptionally active ribosomal DNA (rDNA) genes are exceedingly susceptible to genotoxic stress. Induction of DNA double-strand breaks (DSBs) in rDNA repeats is associated with ataxia-telangiectasia-mutated (ATM)-dependent rDNA silencing and nucleolar reorganization where rDNA is segregated into nucleolar caps. However, the regulatory events underlying this response remain elusive. Here, we identify protein UFMylation as essential for rDNA-damage response in human cells. We further show the only ubiquitin-fold modifier 1 (UFM1)-E3 ligase UFL1 and its binding partner DDRGK1 localize to nucleolar caps upon rDNA damage and that UFL1 loss impairs ATM activation and rDNA transcriptional silencing, leading to reduced rDNA segregation. Moreover, analysis of nuclear and nucleolar UFMylation targets in response to DSB induction further identifies key DNA-repair factors including ATM, in addition to chromatin and actin network regulators. Taken together, our data provide evidence of an essential role for UFMylation in orchestrating rDNA DSB repair.
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Affiliation(s)
- Pudchalaluck Panichnantakul
- Institut de recherches cliniques de Montréal, Center for Genetic and Neurological Diseases, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, QC H4A 3J1, Canada
| | - Lisbeth C Aguilar
- Institut de recherches cliniques de Montréal, Center for Genetic and Neurological Diseases, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Evan Daynard
- Institut de recherches cliniques de Montréal, Center for Genetic and Neurological Diseases, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Mackenzie Guest
- Institut de recherches cliniques de Montréal, Center for Genetic and Neurological Diseases, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Colten Peters
- Department of Biology, Faculty of Medicine, McGill University, Montréal, QC H3A 1B1, Canada
| | - Jackie Vogel
- Department of Biology, Faculty of Medicine, McGill University, Montréal, QC H3A 1B1, Canada
| | - Marlene Oeffinger
- Institut de recherches cliniques de Montréal, Center for Genetic and Neurological Diseases, 110 avenue des Pins Ouest, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, QC H4A 3J1, Canada; Département de biochimie et médicine moléculaire, Faculté de Médicine, Université de Montréal, Montréal, QC H3C 3J7, Canada.
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2
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Li HY, Wang M, Jiang X, Jing Y, Wu Z, He Y, Yan K, Sun S, Ma S, Ji Z, Wang S, Belmonte JCI, Qu J, Zhang W, Wei T, Liu GH. CRISPR screening uncovers nucleolar RPL22 as a heterochromatin destabilizer and senescence driver. Nucleic Acids Res 2024:gkae740. [PMID: 39258545 DOI: 10.1093/nar/gkae740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 08/02/2024] [Accepted: 08/16/2024] [Indexed: 09/12/2024] Open
Abstract
Dysfunction of the ribosome manifests during cellular senescence and contributes to tissue aging, functional decline, and development of aging-related disorders in ways that have remained enigmatic. Here, we conducted a comprehensive CRISPR-based loss-of-function (LOF) screen of ribosome-associated genes (RAGs) in human mesenchymal progenitor cells (hMPCs). Through this approach, we identified ribosomal protein L22 (RPL22) as the foremost RAG whose deficiency mitigates the effects of cellular senescence. Consequently, absence of RPL22 delays hMPCs from becoming senescent, while an excess of RPL22 accelerates the senescence process. Mechanistically, we found in senescent hMPCs, RPL22 accumulates within the nucleolus. This accumulation triggers a cascade of events, including heterochromatin decompaction with concomitant degradation of key heterochromatin proteins, specifically heterochromatin protein 1γ (HP1γ) and heterochromatin protein KRAB-associated protein 1 (KAP1). Subsequently, RPL22-dependent breakdown of heterochromatin stimulates the transcription of ribosomal RNAs (rRNAs), triggering cellular senescence. In summary, our findings unveil a novel role for nucleolar RPL22 as a destabilizer of heterochromatin and a driver of cellular senescence, shedding new light on the intricate mechanisms underlying the aging process.
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Affiliation(s)
- Hong-Yu Li
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Min Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoyu Jiang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Yaobin Jing
- International center for Aging and Cancer, Hainan Academy of Medical Sciences, Hainan Medical University, Haikou 571199, China
| | - Zeming Wu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Yifang He
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Kaowen Yan
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuhui Sun
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuai Ma
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
- Aging Biomarker Consortium, Beijing 100101, China
| | - Zhejun Ji
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Si Wang
- Advanced Innovation Center for Human Brain Protection, and National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, China
- Aging Translational Medicine Center, Beijing Municipal Geriatric Medical Research Center, Xuanwu Hospital, Capital Medical University, Beijing, China
- Aging Biomarker Consortium, Beijing 100101, China
| | | | - Jing Qu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
- Aging Biomarker Consortium, Beijing 100101, China
| | - Weiqi Zhang
- CAS key laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences and China National Center for Bioinformation, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
- Aging Biomarker Consortium, Beijing 100101, China
| | - Taotao Wei
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang-Hui Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
- International center for Aging and Cancer, Hainan Academy of Medical Sciences, Hainan Medical University, Haikou 571199, China
- Advanced Innovation Center for Human Brain Protection, and National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, China
- Aging Translational Medicine Center, Beijing Municipal Geriatric Medical Research Center, Xuanwu Hospital, Capital Medical University, Beijing, China
- Aging Biomarker Consortium, Beijing 100101, China
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3
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Gokhman VE, Kuznetsova VG. Structure and Evolution of Ribosomal Genes of Insect Chromosomes. INSECTS 2024; 15:593. [PMID: 39194798 DOI: 10.3390/insects15080593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Revised: 07/25/2024] [Accepted: 08/02/2024] [Indexed: 08/29/2024]
Abstract
Currently, clusters of 45S and 5S ribosomal DNA (rDNA) have been studied in about 1000 and 100 species of the class Insecta, respectively. Although the number of insect species with known 45S rDNA clusters (also referred to as nucleolus-organizing regions, or NORs) constitutes less than 0.1 percent of the described members of this enormous group, certain conclusions can already be drawn. Since haploid karyotypes with single 45S and 5S rDNA clusters predominate in both basal and derived insect groups, this character state is apparently ancestral for the class Insecta in general. Nevertheless, the number, chromosomal location, and other characteristics of both 45S and 5S rDNA sites substantially vary across different species, and sometimes even within the same species. There are several main factors and molecular mechanisms that either maintain these parameters or alter them on the short-term and/or long-term scale. Chromosome structure (i.e., monocentric vs. holokinetic chromosomes), excessive numbers of rRNA gene copies per cluster, interactions with transposable elements, pseudogenization, and meiotic recombination are perhaps the most important among them.
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Affiliation(s)
| | - Valentina G Kuznetsova
- Department of Karyosystematics, Zoological Institute, Russian Academy of Sciences, St. Petersburg 199034, Russia
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4
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Boukoura S, Larsen DH. Nucleolar organization and ribosomal DNA stability in response to DNA damage. Curr Opin Cell Biol 2024; 89:102380. [PMID: 38861757 DOI: 10.1016/j.ceb.2024.102380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/13/2024]
Abstract
Eukaryotic nuclei are structured into sub-compartments orchestrating various cellular functions. The nucleolus is the largest nuclear organelle: a biomolecular condensate with an architecture composed of immiscible fluids facilitating ribosome biogenesis. The nucleolus forms upon the transcription of the repetitive ribosomal RNA genes (rDNA) that cluster in this compartment. rDNA is intrinsically unstable and prone to rearrangements and copy number variation. Upon DNA damage, a specialized nucleolar-DNA Damage Response (n-DDR) is activated: nucleolar transcription is inhibited, the architecture is rearranged, and rDNA is relocated to the nucleolar periphery. Recent data have highlighted how the composition of nucleoli, its structure, chemical and physical properties, contribute to rDNA stability. In this mini-review we focus on recent data that start to reveal how nucleolar composition and the n-DDR work together to ensure rDNA integrity.
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Affiliation(s)
- Stavroula Boukoura
- Nucleolar Stress and Disease Group, Danish Cancer Institute, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Dorthe Helena Larsen
- Nucleolar Stress and Disease Group, Danish Cancer Institute, Strandboulevarden 49, 2100 Copenhagen, Denmark.
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5
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Donnio LM, Giglia-Mari G. Keep calm and reboot - how cells restart transcription after DNA damage and DNA repair. FEBS Lett 2024. [PMID: 38991979 DOI: 10.1002/1873-3468.14964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/12/2024] [Accepted: 04/21/2024] [Indexed: 07/13/2024]
Abstract
The effects of genotoxic agents on DNA and the processes involved in their removal have been thoroughly studied; however, very little is known about the mechanisms governing the reinstatement of cellular activities after DNA repair, despite restoration of the damage-induced block of transcription being essential for cell survival. In addition to impeding transcription, DNA lesions have the potential to disrupt the precise positioning of chromatin domains within the nucleus and alter the meticulously organized architecture of the nucleolus. Alongside the necessity of resuming transcription mediated by RNA polymerase 1 and 2 transcription, it is crucial to restore the structure of the nucleolus to facilitate optimal ribosome biogenesis and ensure efficient and error-free translation. Here, we examine the current understanding of how transcriptional activity from RNA polymerase 2 is reinstated following DNA repair completion and explore the mechanisms involved in reassembling the nucleolus to safeguard the correct progression of cellular functions. Given the lack of information on this vital function, this Review seeks to inspire researchers to explore deeper into this specific subject and offers essential suggestions on how to investigate this complex and nearly unexplored process further.
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Affiliation(s)
- Lise-Marie Donnio
- Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG_PGNM), CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Lyon, 69008, France
| | - Giuseppina Giglia-Mari
- Institut NeuroMyoGène-Pathophysiology and Genetics of Neuron and Muscle (INMG_PGNM), CNRS UMR 5261, INSERM U1315, Université Claude Bernard Lyon 1, Lyon, 69008, France
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Leng X, Zhang M, Xu Y, Wang J, Ding N, Yu Y, Sun S, Dai W, Xue X, Li N, Yang Y, Shi Z. Non-coding RNAs as therapeutic targets in cancer and its clinical application. J Pharm Anal 2024; 14:100947. [PMID: 39149142 PMCID: PMC11325817 DOI: 10.1016/j.jpha.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/12/2024] [Accepted: 02/01/2024] [Indexed: 08/17/2024] Open
Abstract
Cancer genomics has led to the discovery of numerous oncogenes and tumor suppressor genes that play critical roles in cancer development and progression. Oncogenes promote cell growth and proliferation, whereas tumor suppressor genes inhibit cell growth and division. The dysregulation of these genes can lead to the development of cancer. Recent studies have focused on non-coding RNAs (ncRNAs), including circular RNA (circRNA), long non-coding RNA (lncRNA), and microRNA (miRNA), as therapeutic targets for cancer. In this article, we discuss the oncogenes and tumor suppressor genes of ncRNAs associated with different types of cancer and their potential as therapeutic targets. Here, we highlight the mechanisms of action of these genes and their clinical applications in cancer treatment. Understanding the molecular mechanisms underlying cancer development and identifying specific therapeutic targets are essential steps towards the development of effective cancer treatments.
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Affiliation(s)
- Xuejiao Leng
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Mengyuan Zhang
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yujing Xu
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Jingjing Wang
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Ning Ding
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yancheng Yu
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Shanliang Sun
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Weichen Dai
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Xin Xue
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Nianguang Li
- National and Local Collaborative Engineering Center of Chinese Medicinal Resources Industrialization and Formulae Innovative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Ye Yang
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Zhihao Shi
- Laboratory of Molecular Design and Drug Discovery, School of Science, China Pharmaceutical University, Nanjing, 211198, China
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7
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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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8
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Hwang SP, Denicourt C. The impact of ribosome biogenesis in cancer: from proliferation to metastasis. NAR Cancer 2024; 6:zcae017. [PMID: 38633862 PMCID: PMC11023387 DOI: 10.1093/narcan/zcae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/23/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
The dysregulation of ribosome biogenesis is a hallmark of cancer, facilitating the adaptation to altered translational demands essential for various aspects of tumor progression. This review explores the intricate interplay between ribosome biogenesis and cancer development, highlighting dynamic regulation orchestrated by key oncogenic signaling pathways. Recent studies reveal the multifaceted roles of ribosomes, extending beyond protein factories to include regulatory functions in mRNA translation. Dysregulated ribosome biogenesis not only hampers precise control of global protein production and proliferation but also influences processes such as the maintenance of stem cell-like properties and epithelial-mesenchymal transition, contributing to cancer progression. Interference with ribosome biogenesis, notably through RNA Pol I inhibition, elicits a stress response marked by nucleolar integrity loss, and subsequent G1-cell cycle arrest or cell death. These findings suggest that cancer cells may rely on heightened RNA Pol I transcription, rendering ribosomal RNA synthesis a potential therapeutic vulnerability. The review further explores targeting ribosome biogenesis vulnerabilities as a promising strategy to disrupt global ribosome production, presenting therapeutic opportunities for cancer treatment.
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Affiliation(s)
- Sseu-Pei Hwang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Catherine Denicourt
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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Tomikawa J. Potential roles of inter-chromosomal interactions in cell fate determination. Front Cell Dev Biol 2024; 12:1397807. [PMID: 38774644 PMCID: PMC11106443 DOI: 10.3389/fcell.2024.1397807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/23/2024] [Indexed: 05/24/2024] Open
Abstract
Mammalian genomic DNA is packed in a small nucleus, and its folding and organization in the nucleus are critical for gene regulation and cell fate determination. In interphase, chromosomes are compartmentalized into certain nuclear spaces and territories that are considered incompatible with each other. The regulation of gene expression is influenced by the epigenetic characteristics of topologically associated domains and A/B compartments within chromosomes (intrachromosomal). Previously, interactions among chromosomes detected via chromosome conformation capture-based methods were considered noise or artificial errors. However, recent studies based on newly developed ligation-independent methods have shown that inter-chromosomal interactions play important roles in gene regulation. This review summarizes the recent understanding of spatial genomic organization in mammalian interphase nuclei and discusses the potential mechanisms that determine cell identity. In addition, this review highlights the potential role of inter-chromosomal interactions in early mouse development.
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Affiliation(s)
- Junko Tomikawa
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, Japan
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10
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Sartsanga C, Phengchat R, Wako T, Fukui K, Ohmido N. Localization and quantitative distribution of a chromatin structural protein Topoisomerase II on plant chromosome using HVTEM and UHVTEM. Micron 2024; 179:103596. [PMID: 38359615 DOI: 10.1016/j.micron.2024.103596] [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: 08/28/2023] [Revised: 01/29/2024] [Accepted: 01/29/2024] [Indexed: 02/17/2024]
Abstract
Topoisomerase II (TopoII) is an essential structural protein of the metaphase chromosome. It maintains the axial compaction of chromosomes during metaphase. It is localized at the axial region of chromosomes and accumulates at the centromeric region in metaphase chromosomes. However, little is known about TopoII localization and distribution in plant chromosomes, except for several publications. We used high voltage transmission electron microscopy (HVTEM) and ultra-high voltage transmission electron microscopy (UHVTEM) in conjunction with immunogold labeling and visualization techniques to detect TopoII and investigate its localization, alignment, and density on the barley chromosome at 1.4 nm scale. We found that HVTEM and UHVTEM combined with immunogold labeling is suitable for the detection of structural proteins, including a single molecule of TopoII. This is because the average size of the gold particles for TopoII visualization after silver enhancement is 8.9 ± 3.9 nm, which is well detected. We found that 31,005 TopoII molecules are distributed along the barley chromosomes in an unspecific pattern at the chromosome arms and accumulate specifically at the nucleolus organizer regions (NORs) and centromeric region. The TopoII density were 1.32-fold, 1.58-fold, and 1.36-fold at the terminal region, at the NORs, and the centromeric region, respectively. The findings of TopoII localization in this study support the multiple reported functions of TopoII in the barley metaphase chromosome.
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Affiliation(s)
- Channarong Sartsanga
- Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, 657-8501, Kobe, Japan
| | - Rinyaporn Phengchat
- Nanotechnology Research Centre, National Research of Council, 11421 Saskatchewan Drive, T6G 2M9 Edmonton, Alberta, Canada
| | - Toshiyuki Wako
- Institute of Crop Sciences, National Agriculture and Food Research Organization, 2-1-1 Kannondai, Tsukuba, Ibaraki 305-8518, Japan
| | - Kiichi Fukui
- Graduate School of Pharmaceutical Sciences, Osaka University, Yamadaoka 1-6, Suita, Osaka 565-0871, Japan
| | - Nobuko Ohmido
- Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, 657-8501, Kobe, Japan.
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Shatskikh AS, Fefelova EA, Klenov MS. Functions of RNAi Pathways in Ribosomal RNA Regulation. Noncoding RNA 2024; 10:19. [PMID: 38668377 PMCID: PMC11054153 DOI: 10.3390/ncrna10020019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 04/29/2024] Open
Abstract
Argonaute proteins, guided by small RNAs, play crucial roles in gene regulation and genome protection through RNA interference (RNAi)-related mechanisms. Ribosomal RNAs (rRNAs), encoded by repeated rDNA units, constitute the core of the ribosome being the most abundant cellular transcripts. rDNA clusters also serve as sources of small RNAs, which are loaded into Argonaute proteins and are able to regulate rDNA itself or affect other gene targets. In this review, we consider the impact of small RNA pathways, specifically siRNAs and piRNAs, on rRNA gene regulation. Data from diverse eukaryotic organisms suggest the potential involvement of small RNAs in various molecular processes related to the rDNA transcription and rRNA fate. Endogenous siRNAs are integral to the chromatin-based silencing of rDNA loci in plants and have been shown to repress rDNA transcription in animals. Small RNAs also play a role in maintaining the integrity of rDNA clusters and may function in the cellular response to rDNA damage. Studies on the impact of RNAi and small RNAs on rRNA provide vast opportunities for future exploration.
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Affiliation(s)
- Aleksei S. Shatskikh
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 26 Vavilov Street, 119334 Moscow, Russia;
| | - Elena A. Fefelova
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia
| | - Mikhail S. Klenov
- Institute of Molecular Genetics, Russian Academy of Sciences, 2 Kurchatov Sq., 123182 Moscow, Russia
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, 368 Plantation Street, Worcester, MA 01605, USA
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Pradhan SK, Lozoya T, Prorok P, Yuan Y, Lehmkuhl A, Zhang P, Cardoso MC. Developmental Changes in Genome Replication Progression in Pluripotent versus Differentiated Human Cells. Genes (Basel) 2024; 15:305. [PMID: 38540366 PMCID: PMC10969796 DOI: 10.3390/genes15030305] [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: 01/26/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 06/14/2024] Open
Abstract
DNA replication is a fundamental process ensuring the maintenance of the genome each time cells divide. This is particularly relevant early in development when cells divide profusely, later giving rise to entire organs. Here, we analyze and compare the genome replication progression in human embryonic stem cells, induced pluripotent stem cells, and differentiated cells. Using single-cell microscopic approaches, we map the spatio-temporal genome replication as a function of chromatin marks/compaction level. Furthermore, we mapped the replication timing of subchromosomal tandem repeat regions and interspersed repeat sequence elements. Albeit the majority of these genomic repeats did not change their replication timing from pluripotent to differentiated cells, we found developmental changes in the replication timing of rDNA repeats. Comparing single-cell super-resolution microscopic data with data from genome-wide sequencing approaches showed comparable numbers of replicons and large overlap in origins numbers and genomic location among developmental states with a generally higher origin variability in pluripotent cells. Using ratiometric analysis of incorporated nucleotides normalized per replisome in single cells, we uncovered differences in fork speed throughout the S phase in pluripotent cells but not in somatic cells. Altogether, our data define similarities and differences on the replication program and characteristics in human cells at different developmental states.
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Affiliation(s)
- Sunil Kumar Pradhan
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; (S.K.P.); (P.P.)
| | - Teresa Lozoya
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; (S.K.P.); (P.P.)
| | - Paulina Prorok
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; (S.K.P.); (P.P.)
| | - Yue Yuan
- Center for Tissue Engineering and Stem Cell Research, Guizhou Medical University, Guiyang 550004, China;
| | - Anne Lehmkuhl
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; (S.K.P.); (P.P.)
| | - Peng Zhang
- Center for Tissue Engineering and Stem Cell Research, Guizhou Medical University, Guiyang 550004, China;
| | - M. Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; (S.K.P.); (P.P.)
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13
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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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14
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Diaz LR, Gil-Ranedo J, Jaworek KJ, Nsek N, Marques JP, Costa E, Hilton DA, Bieluczyk H, Warrington O, Hanemann CO, Futschik ME, Bossing T, Barros CS. Ribogenesis boosts controlled by HEATR1-MYC interplay promote transition into brain tumour growth. EMBO Rep 2024; 25:168-197. [PMID: 38225354 PMCID: PMC10897169 DOI: 10.1038/s44319-023-00017-1] [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: 02/06/2023] [Revised: 11/16/2023] [Accepted: 11/22/2023] [Indexed: 01/17/2024] Open
Abstract
Cell commitment to tumourigenesis and the onset of uncontrolled growth are critical determinants in cancer development but the early events directing tumour initiating cell (TIC) fate remain unclear. We reveal a single-cell transcriptome profile of brain TICs transitioning into tumour growth using the brain tumour (brat) neural stem cell-based Drosophila model. Prominent changes in metabolic and proteostasis-associated processes including ribogenesis are identified. Increased ribogenesis is a known cell adaptation in established tumours. Here we propose that brain TICs boost ribogenesis prior to tumour growth. In brat-deficient TICs, we show that this dramatic change is mediated by upregulated HEAT-Repeat Containing 1 (HEATR1) to promote ribosomal RNA generation, TIC enlargement and onset of overgrowth. High HEATR1 expression correlates with poor glioma patient survival and patient-derived glioblastoma stem cells rely on HEATR1 for enhanced ribogenesis and tumourigenic potential. Finally, we show that HEATR1 binds the master growth regulator MYC, promotes its nucleolar localisation and appears required for MYC-driven ribogenesis, suggesting a mechanism co-opted in ribogenesis reprogramming during early brain TIC development.
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Affiliation(s)
- Laura R Diaz
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Jon Gil-Ranedo
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Karolina J Jaworek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- School of Biological Sciences, Bangor University, LL57 2UW, Bangor, UK
| | - Nsikan Nsek
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Joao Pinheiro Marques
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Eleni Costa
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - David A Hilton
- Department of Cellular and Anatomical Pathology, University Hospitals Plymouth, PL6 8DH, Plymouth, UK
| | - Hubert Bieluczyk
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Oliver Warrington
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, WC1N 3AR, London, UK
| | - C Oliver Hanemann
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Matthias E Futschik
- School of Biomedical Sciences, Faculty of Health, Derriford Research Facility, University of Plymouth, PL6 8BU, Plymouth, UK
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-504, Coimbra, Portugal
| | - Torsten Bossing
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK
| | - Claudia S Barros
- Peninsula Medical School, Faculty of Health, John Bull Building, University of Plymouth, PL6 8BU, Plymouth, UK.
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15
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van Bueren MAE, Janssen A. The impact of chromatin on double-strand break repair: Imaging tools and discoveries. DNA Repair (Amst) 2024; 133:103592. [PMID: 37976899 DOI: 10.1016/j.dnarep.2023.103592] [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: 10/16/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Eukaryotic nuclei are constantly being exposed to factors that break or chemically modify the DNA. Accurate repair of this DNA damage is crucial to prevent DNA mutations and maintain optimal cell function. To overcome the detrimental effects of DNA damage, a multitude of repair pathways has evolved. These pathways need to function properly within the different chromatin domains present in the nucleus. Each of these domains exhibit distinct molecular- and bio-physical characteristics that can influence the response to DNA damage. In particular, chromatin domains highly enriched for repetitive DNA sequences, such as nucleoli, centromeres and pericentromeric heterochromatin require tailored repair mechanisms to safeguard genome stability. Work from the past decades has led to the development of innovative imaging tools as well as inducible DNA damage techniques to gain new insights into the impact of these repetitive chromatin domains on the DNA repair process. Here we summarize these tools with a particular focus on Double-Strand Break (DSB) repair, and discuss the insights gained into our understanding of the influence of chromatin domains on DSB -dynamics and -repair pathway choice.
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Affiliation(s)
- Marit A E van Bueren
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Aniek Janssen
- Center for Molecular Medicine, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
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16
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Zareie AR, Verma SC. Nucleolin Regulates the Expression of Kaposi's Sarcoma-Associated Herpesvirus' Latency-Associated Nuclear Antigen through G-Quadruplexes in the mRNA. Viruses 2023; 15:2438. [PMID: 38140679 PMCID: PMC10747643 DOI: 10.3390/v15122438] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 12/24/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) establishes life-long latent infection and is linked to several human malignancies. Latency-associated nuclear antigen (LANA) is highly expressed during latency, and is responsible for the replication and maintenance of the viral genome. The expression of LANA is regulated at transcriptional/translational levels through multiple mechanisms, including the secondary structures in the mRNA sequence. LANA mRNA has multiple G-quadruplexes (G4s) that are bound by multiple proteins to stabilize/destabilize these secondary structures for regulating LANA. In this manuscript, we demonstrate the role of Nucleolin (NCL) in regulating LANA expression through its interaction with G-quadruplexes of LANA mRNA. This interaction reduced LANA's protein expression through the sequestration of mRNA into the nucleus, demonstrated by the colocalization of G4-carrying mRNA with NCL. Furthermore, the downregulation of NCL, by way of a short hairpin, showed an increase in LANA translation following an alteration in the levels of LANA mRNA in the cytoplasm. Overall, the data presented in this manuscript showed that G-quadruplexes-mediated translational control could be regulated by NCL, which can be exploited for controlling KSHV latency.
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Affiliation(s)
| | - Subhash C. Verma
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, 1664 N Virginia Street, Reno, NV 89557, USA;
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17
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Courret C, Larracuente AM. High levels of intra-strain structural variation in Drosophila simulans X pericentric heterochromatin. Genetics 2023; 225:iyad176. [PMID: 37768175 PMCID: PMC10697818 DOI: 10.1093/genetics/iyad176] [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: 08/12/2023] [Revised: 08/12/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Large genome structural variations can impact genome regulation and integrity. Repeat-rich regions like pericentric heterochromatin are vulnerable to structural rearrangements although we know little about how often these rearrangements occur over evolutionary time. Repetitive genome regions are particularly difficult to study with genomic approaches, as they are missing from most genome assemblies. However, cytogenetic approaches offer a direct way to detect large rearrangements involving pericentric heterochromatin. Here, we use a cytogenetic approach to reveal large structural rearrangements associated with the X pericentromeric region of Drosophila simulans. These rearrangements involve large blocks of satellite DNA-the 500-bp and Rsp-like satellites-which colocalize in the X pericentromeric heterochromatin. We find that this region is polymorphic not only among different strains, but between isolates of the same strain from different labs, and even within individual isolates. On the one hand, our observations raise questions regarding the potential impact of such variation at the phenotypic level and our ability to control for such genetic variability. On the other hand, this highlights the very rapid turnover of the pericentric heterochromatin most likely associated with genomic instability of the X pericentromere. It represents a unique opportunity to study the dynamics of pericentric heterochromatin, the evolution of associated satellites on a very short time scale, and to better understand how structural variation arises.
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Affiliation(s)
- Cécile Courret
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
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18
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Yamashita YM. Asymmetric Stem Cell Division and Germline Immortality. Annu Rev Genet 2023; 57:181-199. [PMID: 37552892 DOI: 10.1146/annurev-genet-022123-040039] [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: 08/10/2023]
Abstract
Germ cells are the only cell type that is capable of transmitting genetic information to the next generation, which has enabled the continuation of multicellular life for the last 1.5 billion years. Surprisingly little is known about the mechanisms supporting the germline's remarkable ability to continue in this eternal cycle, termed germline immortality. Even unicellular organisms age at a cellular level, demonstrating that cellular aging is inevitable. Extensive studies in yeast have established the framework of how asymmetric cell division and gametogenesis may contribute to the resetting of cellular age. This review examines the mechanisms of germline immortality-how germline cells reset the aging of cells-drawing a parallel between yeast and multicellular organisms.
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Affiliation(s)
- Yukiko M Yamashita
- Whitehead Institute for Biomedical Research, Howard Hughes Medical Institute, and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA;
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19
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Fultz D, McKinlay A, Enganti R, Pikaard CS. Sequence and epigenetic landscapes of active and silent nucleolus organizer regions in Arabidopsis. SCIENCE ADVANCES 2023; 9:eadj4509. [PMID: 37910609 PMCID: PMC10619934 DOI: 10.1126/sciadv.adj4509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/27/2023] [Indexed: 11/03/2023]
Abstract
Arabidopsis thaliana has two ribosomal RNA (rRNA) gene loci, nucleolus organizer regions NOR2 and NOR4, whose complete sequences are missing in current genome assemblies. Ultralong DNA sequences assembled using an unconventional approach yielded ~5.5- and 3.9-Mbp sequences for NOR2 and NOR4 in the reference strain, Col-0. The distinct rRNA gene subtype compositions of the NORs enabled the positional mapping of their active and inactive regions, using RNA sequencing to identify subtype-specific transcripts and DNA sequencing to identify subtypes associated with flow-sorted nucleoli. Comparisons of wild-type and silencing-defective plants revealed that most rRNA gene activity occurs in the central region of NOR4, whereas most, but not all, genes of NOR2 are epigenetically silenced. Intervals of low CG and CHG methylation overlap regions where gene activity and gene subtype homogenization are high. Collectively, the data reveal the genetic and epigenetic landscapes underlying nucleolar dominance (differential NOR activity) and implicate transcription as a driver of rRNA gene concerted evolution.
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Affiliation(s)
- Dalen Fultz
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN, USA
- Department of Biology, Indiana University, Bloomington, IN, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Anastasia McKinlay
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN, USA
- Department of Biology, Indiana University, Bloomington, IN, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Ramya Enganti
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN, USA
- Department of Biology, Indiana University, Bloomington, IN, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Craig S. Pikaard
- Howard Hughes Medical Institute, Indiana University, Bloomington, IN, USA
- Department of Biology, Indiana University, Bloomington, IN, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN, USA
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20
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Blokhina Y, Buchwalter A. Modeling the consequences of age-linked rDNA hypermethylation with dCas9-directed DNA methylation in human cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.18.562830. [PMID: 37904963 PMCID: PMC10614900 DOI: 10.1101/2023.10.18.562830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Ribosomal DNA (rDNA) genes encode the structural RNAs of the ribosome and are present in hundreds of copies in mammalian genomes. Age-linked DNA hypermethylation throughout the rDNA constitutes a robust "methylation clock" that accurately reports age, yet the consequences of hypermethylation on rDNA function are unknown. We confirmed that pervasive hypermethylation of rDNA occurs during mammalian aging and senescence while rDNA copy number remains stable. We found that DNA methylation is exclusively found on the promoters and gene bodies of inactive rDNA. To model the effects of age-linked methylation on rDNA function, we directed de novo DNA methylation to the rDNA promoter or gene body with a nuclease-dead Cas9 (dCas9) - DNA methyltransferase fusion enzyme in human cells. Hypermethylation at each target site had no detectable effect on rRNA transcription, nucleolar morphology, or cellular growth rate. Instead, human UBF and Pol I remain bound to rDNA promoters in the presence of increased DNA methylation. These data suggest that promoter methylation is not sufficient to impair transcription of the human rDNA and imply that the human rDNA transcription machinery may be resilient to age-linked rDNA hypermethylation.
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Affiliation(s)
- Yana Blokhina
- Cardiovascular Research Institute and Department of Physiology, University of California, San Francisco
- present address: NewLimit, South San Francisco, CA
| | - Abigail Buchwalter
- Cardiovascular Research Institute and Department of Physiology, University of California, San Francisco
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21
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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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22
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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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23
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Aziz F, Shoaib N, Rehman A. Hub genes identification and association of key pathways with hypoxia in cancer cells: A bioinformatics analysis. Saudi J Biol Sci 2023; 30:103752. [PMID: 37593462 PMCID: PMC10428120 DOI: 10.1016/j.sjbs.2023.103752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/17/2023] [Accepted: 07/22/2023] [Indexed: 08/19/2023] Open
Abstract
Three human cancer cell lines (A549, HCT116, and HeLa) were used to investigate the molecular mechanisms and potential prognostic biomarkers associated with hypoxia. We obtained gene expression data from Gene Expression Omnibus (GEO) datasets GSE11704, GSE147384, and GSE38061, which included 5 hypoxic and 8 control samples. Using the GEO2R tool and Venn diagram software, we identified common differentially expressed genes (cDEGs). The cDEGs were then subjected to Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis by employing DAVID. The hub genes were identified from critical PPI subnetworks through CytoHuba plugin and these genes' prognostic significance and expression were verified using Kaplan-Meier analysis and Gene Expression Profiling Interactive Analysis (GEPIA), respectively. The research showed 676 common DEGs (cDEGs), with 207 upregulated and 469 downregulated genes. The STRING analysis showed 673 nodes and 1446 edges in the PPI network. We identified 4 significant modules and 19 downregulated hub genes. GO analysis revealed all of them were majorly involved in ribosomal large subunit assembly and biogenesis, rRNA processing, ribosome biogenesis, translation, RNA & protein binding frequently at the sites of nucleolus and nucleoplasm while 11 were significantly associated with a better prognosis of hypoxic tumors. Our research sheds light on the molecular mechanisms that underpin hypoxia in human cancer cell lines and identifies potential prognostic biomarkers for hypoxic tumors.
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Affiliation(s)
- Faiza Aziz
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, 54590 Lahore, Pakistan
| | - Naila Shoaib
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, 54590 Lahore, Pakistan
| | - Abdul Rehman
- Institute of Microbiology and Molecular Genetics, University of the Punjab, Quaid-e-Azam Campus, 54590 Lahore, Pakistan
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Huang Y, Liu Y, Guo X, Fan C, Yi C, Shi Q, Su H, Liu C, Yuan J, Liu D, Yang W, Han F. New insights on the evolution of nucleolar dominance in newly resynthesized hexaploid wheat Triticum zhukovskyi. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1298-1315. [PMID: 37246611 DOI: 10.1111/tpj.16320] [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: 01/11/2023] [Revised: 05/11/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Nucleolar dominance (ND) is a widespread epigenetic phenomenon in hybridizations where nucleolus transcription fails at the nucleolus organizer region (NOR). However, the dynamics of NORs during the formation of Triticum zhukovskyi (GGAu Au Am Am ), another evolutionary branch of allohexaploid wheat, remains poorly understood. Here, we elucidated genetic and epigenetic changes occurring at the NOR loci within the Am , G, and D subgenomes during allopolyploidization by synthesizing hexaploid wheat GGAu Au Am Am and GGAu Au DD. In T. zhukovskyi, Au genome NORs from T. timopheevii (GGAu Au ) were lost, while the second incoming NORs from T. monococcum (Am Am ) were retained. Analysis of the synthesized T. zhukovskyi revealed that rRNA genes from the Am genome were silenced in F1 hybrids (GAu Am ) and remained inactive after genome doubling and subsequent self-pollinations. We observed increased DNA methylation accompanying the inactivation of NORs in the Am genome and found that silencing of NORs in the S1 generation could be reversed by a cytidine methylase inhibitor. Our findings provide insights into the ND process during the evolutionary period of T. zhukovskyi and highlight that inactive rDNA units may serve as a 'first reserve' in the form of R-loops, contributing to the successful evolution of T. zhukovskyi.
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Affiliation(s)
- Yuhong Huang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xianrui Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chaolan Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Congyang Yi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qinghua Shi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Handong Su
- Huazhong Agricultural University, Hubei, 430070, China
| | - Chang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Yuan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dengcai Liu
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wuyun Yang
- Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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25
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Xu D, Chen X, Kuang Y, Hong M, Xu T, Wang K, Huang X, Fu C, Ruan K, Zhu C, Feng X, Guang S. rRNA intermediates coordinate the formation of nucleolar vacuoles in C. elegans. Cell Rep 2023; 42:112915. [PMID: 37537842 DOI: 10.1016/j.celrep.2023.112915] [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: 04/17/2023] [Revised: 07/03/2023] [Accepted: 07/17/2023] [Indexed: 08/05/2023] Open
Abstract
The nucleolus is the most prominent membraneless organelle within the nucleus. How the nucleolar structure is regulated is poorly understood. Here, we identified two types of nucleoli in C. elegans. Type I nucleoli are spherical and do not have visible nucleolar vacuoles (NoVs), and rRNA transcription and processing factors are evenly distributed throughout the nucleolus. Type II nucleoli contain vacuoles, and rRNA transcription and processing factors exclusively accumulate in the periphery rim. The NoV contains nucleoplasmic proteins and is capable of exchanging contents with the nucleoplasm. The high-order structure of the nucleolus is dynamically regulated in C. elegans. Faithful rRNA processing is important to prohibit NoVs. The depletion of 27SA2 rRNA processing factors resulted in NoV formation. The inhibition of RNA polymerase I (RNAPI) transcription and depletion of two conserved nucleolar factors, nucleolin and fibrillarin, prohibits the formation of NoVs. This finding provides a mechanism to coordinate structure maintenance and gene expression.
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Affiliation(s)
- Demin Xu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xiangyang Chen
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Yan Kuang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Minjie Hong
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ting Xu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ke Wang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Xinya Huang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Chuanhai Fu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ke Ruan
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Chengming Zhu
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Xuezhu Feng
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China.
| | - Shouhong Guang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of USTC, The USTC RNA Institute, Ministry of Education Key Laboratory for Membraneless Organelles & Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, Anhui 230027, China; CAS Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Hefei, Anhui 230027, China.
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26
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Abstract
The p-arms of the five human acrocentric chromosomes bear nucleolar organizer regions (NORs) comprising ribosomal gene (rDNA) repeats that are organized in a homogeneous tandem array and transcribed in a telomere-to-centromere direction. Precursor ribosomal RNA transcripts are processed and assembled into ribosomal subunits, the nucleolus being the physical manifestation of this process. I review current understanding of nucleolar chromosome biology and describe current exploration into a role for the NOR chromosomal context. Full DNA sequences for acrocentric p-arms are now emerging, aided by the current revolution in long-read sequencing and genome assembly. Acrocentric p-arms vary from 10.1 to 16.7 Mb, accounting for ∼2.2% of the genome. Bordering rDNA arrays, distal junctions, and proximal junctions are shared among the p-arms, with distal junctions showing evidence of functionality. The remaining p-arm sequences comprise multiple satellite DNA classes and segmental duplications that facilitate recombination between heterologous chromosomes, which is likely also involved in Robertsonian translocations.
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Affiliation(s)
- Brian McStay
- Centre for Chromosome Biology, College of Science and Engineering, University of Galway, Galway, Ireland;
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27
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Delorme-Hinoux V, Mbodj A, Brando S, De Bures A, Llauro C, Covato F, Garrigue J, Guisset C, Borrut J, Mirouze M, Reichheld JP, Sáez-Vásquez J. 45S rDNA Diversity In Natura as One Step towards Ribosomal Heterogeneity in Arabidopsis thaliana. PLANTS (BASEL, SWITZERLAND) 2023; 12:2722. [PMID: 37514338 PMCID: PMC10386311 DOI: 10.3390/plants12142722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
The keystone of ribosome biogenesis is the transcription of 45S rDNA. The Arabidopsis thaliana genome contains hundreds of 45S rDNA units; however, they are not all transcribed. Notably, 45S rDNA units contain insertions/deletions revealing the existence of heterogeneous rRNA genes and, likely, heterogeneous ribosomes for rRNAs. In order to obtain an overall picture of 45S rDNA diversity sustaining the synthesis of rRNAs and, subsequently, of ribosomes in natura, we took advantage of 320 new occurrences of Arabidopsis thaliana as a metapopulation named At66, sampled from 0 to 1900 m of altitude in the eastern Pyrenees in France. We found that the 45S rDNA copy number is very dynamic in natura and identified new genotypes for both 5' and 3' External Transcribed Spacers (ETS). Interestingly, the highest 5'ETS genotype diversity is found in altitude while the highest 3'ETS genotype diversity is found at sea level. Structural analysis of 45S rDNA also shows conservation in natura of specific 5'ETS and 3'ETS sequences/features required to control rDNA expression and the processing of rRNAs. In conclusion, At66 is a worthwhile natural laboratory, and unraveled 45S rDNA diversity represents an interesting starting material to select subsets for rDNA transcription and alter the rRNA composition of ribosomes both intra- and inter-site.
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Affiliation(s)
- Valérie Delorme-Hinoux
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- EMR LGDP/MANGO, Mechanisms of Adaptation and Genomics, IRD-CNRS-UPVD, 66860 Perpignan, France
- Association Charles Flahault, 66350 Toulouges, France
| | - Assane Mbodj
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- EMR LGDP/MANGO, Mechanisms of Adaptation and Genomics, IRD-CNRS-UPVD, 66860 Perpignan, France
- Institut de Recherche pour le Développement (IRD), ECOBIO, 34000 Montpellier, France
| | - Sophie Brando
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
| | - Anne De Bures
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
| | - Christel Llauro
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- EMR LGDP/MANGO, Mechanisms of Adaptation and Genomics, IRD-CNRS-UPVD, 66860 Perpignan, France
| | - Fabrice Covato
- FRNC, Fédération des Réserves Naturelles Catalanes, 66500 Prades, France
| | - Joseph Garrigue
- FRNC, Fédération des Réserves Naturelles Catalanes, 66500 Prades, France
| | - Claude Guisset
- Association Charles Flahault, 66350 Toulouges, France
- FRNC, Fédération des Réserves Naturelles Catalanes, 66500 Prades, France
| | | | - Marie Mirouze
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- EMR LGDP/MANGO, Mechanisms of Adaptation and Genomics, IRD-CNRS-UPVD, 66860 Perpignan, France
- Institut de Recherche pour le Développement (IRD), ECOBIO, 34000 Montpellier, France
| | - Jean-Philippe Reichheld
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
| | - Julio Sáez-Vásquez
- Université de Perpignan Via Domitia (UPVD), Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
- Centre National de la Recherche Scientifique, Laboratoire Génome et Développement des Plantes (LGDP), UMR 5096, 66860 Perpignan, France
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28
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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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29
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Santana-Sosa S, Matos-Perdomo E, Ayra-Plasencia J, Machín F. A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace. Int J Mol Sci 2023; 24:9829. [PMID: 37372977 DOI: 10.3390/ijms24129829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
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Affiliation(s)
- Silvia Santana-Sosa
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Emiliano Matos-Perdomo
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Félix Machín
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Faculty of Health Sciences, Fernando Pessoa Canarias University, 35450 Santa María de Guía, Spain
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30
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Georgi JA, Stasik S, Eckardt JN, Zukunft S, Hartwig M, Röllig C, Middeke JM, Oelschlägel U, Krug U, Sauer T, Scholl S, Hochhaus A, Brümmendorf TH, Naumann R, Steffen B, Einsele H, Schaich M, Burchert A, Neubauer A, Schäfer-Eckart K, Schliemann C, Krause SW, Hänel M, Noppeney R, Kaiser U, Baldus CD, Kaufmann M, Müller-Tidow C, Platzbecker U, Berdel WE, Serve H, Ehninger G, Bornhäuser M, Schetelig J, Kroschinsky F, Thiede C. UBTF tandem duplications are rare but recurrent alterations in adult AML and associated with younger age, myelodysplasia, and inferior outcome. Blood Cancer J 2023; 13:88. [PMID: 37236968 DOI: 10.1038/s41408-023-00858-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/03/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
Tandem-duplication mutations of the UBTF gene (UBTF-TDs) coding for the upstream binding transcription factor have recently been described in pediatric patients with acute myeloid leukemia (AML) and were found to be associated with particular genetics (trisomy 8 (+8), FLT3-internal tandem duplications (FLT3-ITD), WT1-mutations) and inferior outcome. Due to limited knowledge on UBTF-TDs in adult AML, we screened 4247 newly diagnosed adult AML and higher-risk myelodysplastic syndrome (MDS) patients using high-resolution fragment analysis. UBTF-TDs were overall rare (n = 52/4247; 1.2%), but significantly enriched in younger patients (median age 41 years) and associated with MDS-related morphology as well as significantly lower hemoglobin and platelet levels. Patients with UBTF-TDs had significantly higher rates of +8 (34% vs. 9%), WT1 (52% vs. 7%) and FLT3-ITD (50% vs. 20.8%) co-mutations, whereas UBTF-TDs were mutually exclusive with several class-defining lesions such as mutant NPM1, in-frame CEBPAbZIP mutations as well as t(8;21). Based on the high-variant allele frequency found and the fact that all relapsed patients analyzed (n = 5) retained the UBTF-TD mutation, UBTF-TDs represent early clonal events and are stable over the disease course. In univariate analysis, UBTF-TDs did not represent a significant factor for overall or relapse-free survival in the entire cohort. However, in patients under 50 years of age, who represent the majority of UBTF-mutant patients, UBTF-TDs were an independent prognostic factor for inferior event-free (EFS), relapse-free (RFS) and overall survival (OS), which was confirmed by multivariable analyses including established risk factors such as age and ELN2022 genetic risk groups (EFS [HR: 2.20; 95% CI 1.52-3.17, p < 0.001], RFS [HR: 1.59; 95% CI 1.02-2.46, p = 0.039] and OS [HR: 1.64; 95% CI 1.08-2.49, p = 0.020]). In summary, UBTF-TDs appear to represent a novel class-defining lesion not only in pediatric AML but also younger adults and are associated with myelodysplasia and inferior outcome in these patients.
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Affiliation(s)
- Julia-Annabell Georgi
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Sebastian Stasik
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Jan-Niklas Eckardt
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Sven Zukunft
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Marita Hartwig
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Christoph Röllig
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Jan Moritz Middeke
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Uta Oelschlägel
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Utz Krug
- Medizinische Klinik 3, Klinikum Leverkusen, Leverkusen, Germany
| | - Tim Sauer
- Universität Heidelberg, Medizinische Klinik und Poliklinik, Abteilung Innere Medizin V, Heidelberg, Germany
| | - Sebastian Scholl
- Klinik für Innere Medizin II, Universitätsklinikum Jena, Jena, Germany
| | - Andreas Hochhaus
- Klinik für Innere Medizin II, Universitätsklinikum Jena, Jena, Germany
| | | | - Ralph Naumann
- Medizinische Klinik III, St. Marien-Krankenhaus Siegen, Siegen, Germany
| | - Björn Steffen
- Medizinische Klinik 2, Hämatologie/Onkologie, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
| | - Hermann Einsele
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Würzburg, Würzburg, Germany
| | - Markus Schaich
- Klinik für Hämatologie, Onkologie und Palliativmedizin, Rems-Murr-Klinikum Winnenden, Winnenden, Germany
| | - Andreas Burchert
- Klinik für Innere Medizin, Schwerpunkt Hämatologie, Onkologie und Immunologie, Philipps Universität Marburg, Marburg, Germany
| | - Andreas Neubauer
- Klinik für Innere Medizin, Schwerpunkt Hämatologie, Onkologie und Immunologie, Philipps Universität Marburg, Marburg, Germany
| | - Kerstin Schäfer-Eckart
- Klinikum Nürnberg, Paracelsus Medizinische Privatuniversität, Medizinische Klinik 5, Nürnberg, Germany
| | | | - Stefan W Krause
- Medizinische Klinik 5, Universitätsklinikum Erlangen, Erlangen, Germany
| | - Mathias Hänel
- Klinik für Innere Medizin III, Klinikum Chemnitz, Chemnitz, Germany
| | - Richard Noppeney
- Klinik für Hämatologie, Universitätsklinikum Essen, Essen, Germany
| | - Ulrich Kaiser
- Medizinische Klinik II, St. Bernward Krankenhaus, Hildesheim, Germany
| | - Claudia D Baldus
- Klinik für Innere Medizin II, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Martin Kaufmann
- Abteilung für Hämatologie, Onkologie und Palliativmedizin, Robert-Bosch-Krankenhaus, Stuttgart, Germany
| | - Carsten Müller-Tidow
- Universität Heidelberg, Medizinische Klinik und Poliklinik, Abteilung Innere Medizin V, Heidelberg, Germany
| | - Uwe Platzbecker
- Klinik und Poliklinik für Hämatologie, Zelltherapie und Hämostaseologie, Universitätsklinikum Leipzig, Leipzig, Germany
| | - Wolfgang E Berdel
- Medizinische Klinik A, Universitätsklinikum Münster, Münster, Germany
| | - Hubert Serve
- Medizinische Klinik 2, Hämatologie/Onkologie, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
| | | | - Martin Bornhäuser
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
- National Center for Tumor Diseases NCT, Dresden, Germany
| | - Johannes Schetelig
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
- DKMS Clinical Trials Unit, Dresden, Germany
| | - Frank Kroschinsky
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany
| | - Christian Thiede
- Medizinische Klinik und Poliklinik 1, Universitätsklinikum Carl Gustav Carus, Dresden, Germany.
- AgenDix GmbH, Dresden, Germany.
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Morton EA, Hall AN, Cuperus JT, Queitsch C. Substantial rDNA copy number reductions alter timing of development and produce variable tissue-specific phenotypes in C. elegans. Genetics 2023; 224:iyad039. [PMID: 36919976 PMCID: PMC10474940 DOI: 10.1093/genetics/iyad039] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/16/2023] Open
Abstract
The genes that encode ribosomal RNAs are present in several hundred copies in most eukaryotes. These vast arrays of repetitive ribosomal DNA (rDNA) have been implicated not just in ribosome biogenesis, but also aging, cancer, genome stability, and global gene expression. rDNA copy number is highly variable among and within species; this variability is thought to associate with traits relevant to human health and disease. Here we investigate the phenotypic consequences of multicellular life at the lower bounds of rDNA copy number. We use the model Caenorhabditis elegans, which has previously been found to complete embryogenesis using only maternally provided ribosomes. We find that individuals with rDNA copy number reduced to ∼5% of wild type are capable of further development with variable penetrance. Such individuals are sterile and exhibit severe morphological defects, particularly in post-embryonically dividing tissues such as germline and vulva. Developmental completion and fertility are supported by an rDNA copy number ∼10% of wild type, with substantially delayed development. Worms with rDNA copy number reduced to ∼33% of wild type display a subtle developmental timing defect that was absent in worms with higher copy numbers. Our results support the hypothesis that rDNA requirements vary across tissues and indicate that the minimum rDNA copy number for fertile adulthood is substantially less than the lowest naturally observed total copy number. The phenotype of individuals with severely reduced rDNA copy number is highly variable in penetrance and presentation, highlighting the need for continued investigation into the biological consequences of rDNA copy number variation.
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Affiliation(s)
| | - Ashley N Hall
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI 53726, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98195, USA
| | - Josh T Cuperus
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
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Liskovykh M, Petrov NS, Noskov VN, Masumoto H, Earnshaw WC, Schlessinger D, Shabalina SA, Larionov V, Kouprina N. Actively transcribed rDNA and distal junction (DJ) sequence are involved in association of NORs with nucleoli. Cell Mol Life Sci 2023; 80:121. [PMID: 37043028 PMCID: PMC10097779 DOI: 10.1007/s00018-023-04770-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/13/2023]
Abstract
Although they are organelles without a limiting membrane, nucleoli have an exclusive structure, built upon the rDNA-rich acrocentric short arms of five human chromosomes (nucleolar organizer regions or NORs). This has raised the question: what are the structural features of a chromosome required for its inclusion in a nucleolus? Previous work has suggested that sequences adjacent to the tandemly repeated rDNA repeat units (DJ, distal junction sequence) may be involved, and we have extended such studies by addressing several issues related to the requirements for the association of NORs with nucleoli. We exploited both a set of somatic cell hybrids containing individual human acrocentric chromosomes and a set of Human Artificial Chromosomes (HACs) carrying different parts of a NOR, including an rDNA unit or DJ or PJ (proximal junction) sequence. Association of NORs with nucleoli was increased when constituent rDNA was transcribed and may be also affected by the status of heterochromatin blocks formed next to the rDNA arrays. Furthermore, our data suggest that a relatively small size DJ region, highly conserved in evolution, is also involved, along with the rDNA repeats, in the localization of p-arms of acrocentric chromosomes in nucleoli. Thus, we infer a cooperative action of rDNA sequence-stimulated by its activity-and sequences distal to rDNA contributing to incorporation into nucleoli. Analysis of NOR sequences also identified LncRNA_038958 in the DJ, a candidate transcript with the region of the suggested promoter that is located close to the DJ/rDNA boundary and contains CTCF binding sites. This LncRNA may affect RNA Polymerase I and/or nucleolar activity. Our findings provide the basis for future studies to determine which RNAs and proteins interact critically with NOR sequences to organize the higher-order structure of nucleoli and their function in normal cells and pathological states.
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Affiliation(s)
- Mikhail Liskovykh
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
| | - Nikolai S Petrov
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Vladimir N Noskov
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD, 20892, USA
| | - Hiroshi Masumoto
- Laboratory of Chromosome Engineering, Department of Frontier Research and Development, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3JR, Scotland, UK
| | - David Schlessinger
- National Institute on Aging, Laboratory of Genetics and Genomics, NIH, Baltimore, MD, 21224, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD, 20892, USA
| | - Vladimir Larionov
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
| | - Natalay Kouprina
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD, 20892, USA.
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Lafita-Navarro MC, Conacci-Sorrell M. Nucleolar stress: From development to cancer. Semin Cell Dev Biol 2023; 136:64-74. [PMID: 35410715 PMCID: PMC9883801 DOI: 10.1016/j.semcdb.2022.04.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/29/2022] [Accepted: 04/02/2022] [Indexed: 02/06/2023]
Abstract
The nucleolus is a large nuclear membraneless organelle responsible for ribosome biogenesis. Ribosomes are cytoplasmic macromolecular complexes comprising RNA and proteins that link amino acids together to form new proteins. The biogenesis of ribosomes is an intricate multistep process that involves the transcription of ribosomal DNA (rDNA), the processing of ribosomal RNA (rRNA), and the assembly of rRNA with ribosomal proteins to form active ribosomes. Nearly all steps necessary for ribosome production and maturation occur in the nucleolus. Nucleolar shape, size, and number are directly linked to ribosome biogenesis. Errors in the steps of ribosomal biogenesis are sensed by the nucleolus causing global alterations in nucleolar function and morphology. This phenomenon, known as nucleolar stress, can lead to molecular changes such as stabilization of p53, which in turn activates cell cycle arrest or apoptosis. In this review, we discuss recent work on the association of nucleolar stress with degenerative diseases and developmental defects. In addition, we highlight the importance of de novo nucleotide biosynthesis for the enhanced nucleolar activity of cancer cells and discuss targeting nucleotide biosynthesis as a strategy to activate nucleolar stress to specifically target cancer cells.
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Affiliation(s)
- M Carmen Lafita-Navarro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | - Maralice Conacci-Sorrell
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA; Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
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34
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Beklemisheva VR, Lemskaya NA, Prokopov DY, Perelman PL, Romanenko SA, Proskuryakova AA, Serdyukova NA, Utkin YA, Nie W, Ferguson-Smith MA, Yang F, Graphodatsky AS. Maps of Constitutive-Heterochromatin Distribution for Four Martes Species (Mustelidae, Carnivora, Mammalia) Show the Formative Role of Macrosatellite Repeats in Interspecific Variation of Chromosome Structure. Genes (Basel) 2023; 14:489. [PMID: 36833416 PMCID: PMC9957230 DOI: 10.3390/genes14020489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/08/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Constitutive-heterochromatin placement in the genome affects chromosome structure by occupying centromeric areas and forming large blocks. To investigate the basis for heterochromatin variation in the genome, we chose a group of species with a conserved euchromatin part: the genus Martes [stone marten (M. foina, 2n = 38), sable (M. zibellina, 2n = 38), pine marten (M. martes, 2n = 38), and yellow-throated marten (M. flavigula, 2n = 40)]. We mined the stone marten genome for the most abundant tandem repeats and selected the top 11 macrosatellite repetitive sequences. Fluorescent in situ hybridization revealed distributions of the tandemly repeated sequences (macrosatellites, telomeric repeats, and ribosomal DNA). We next characterized the AT/GC content of constitutive heterochromatin by CDAG (Chromomycin A3-DAPI-after G-banding). The euchromatin conservatism was shown by comparative chromosome painting with stone marten probes in newly built maps of the sable and pine marten. Thus, for the four Martes species, we mapped three different types of tandemly repeated sequences critical for chromosome structure. Most macrosatellites are shared by the four species with individual patterns of amplification. Some macrosatellites are specific to a species, autosomes, or the X chromosome. The variation of core macrosatellites and their prevalence in a genome are responsible for the species-specific variation of the heterochromatic blocks.
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Affiliation(s)
- Violetta R. Beklemisheva
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Natalya A. Lemskaya
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Dmitry Yu. Prokopov
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Polina L. Perelman
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Svetlana A. Romanenko
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Anastasia A. Proskuryakova
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Natalya A. Serdyukova
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Yaroslav A. Utkin
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Wenhui Nie
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Malcolm A. Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Fentang Yang
- School of Life Sciences and Medicine, Shandong University of Technology, Zibo 255049, China
| | - Alexander S. Graphodatsky
- Department of Diversity and Evolution of Genomes, Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
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35
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Venancio S, Noleto RB, Azambuja M, Gazolla CB, Santos BR, Nogaroto V, Vicari MR. Comparative cytogenetics among Boana species (Anura, Hylidae): focus on evolutionary variability of repetitive DNA. Genet Mol Biol 2023; 45:e20220203. [PMID: 36622243 PMCID: PMC9827724 DOI: 10.1590/1678-4685-gmb-2022-0203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/08/2022] [Indexed: 01/10/2023] Open
Abstract
Boana comprises a diverse genus of Neotropical treefrogs, currently rearranged into seven taxonomic species groups. Although cytogenetic studies have demonstrated diversity in its representatives, the chromosomal mapping of repetitive DNA sequences is still scarce. In this study, Boana albopunctata, Boana faber, and Boana prasina were subjected to in situ localization of different repetitive DNA units to evaluate trends of chromosomal evolution in this genus. Boana faber and B. prasina had 2n=24 chromosomes, while B. albopunctata has 2n=22 and an intra-individual variation related to the presence/absence of one B chromosome. The location of 45S rDNA sites was different in the analyzed karyotypes, corroborating with what was found in the distinct phylogenetic groups of Boana. We presented the first description of 5S rDNA in a Boana species, which showed markings resulting from transposition/translocation mechanisms. In situ localization of microsatellite loci proved to be a helpful marker for karyotype comparison in Boana, commonly with cis accumulation in the heterochromatin. On the other hand, genomic dispersion of microsatellites may be associated with hitchhiking effects during the spreading of transposable elements. The obtained results corroborated the independent diversification of these lineages of species from three distinct phylogenetic groups of Boana.
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Affiliation(s)
- Sebastião Venancio
- Universidade Federal do Paraná, Centro Politécnico, Departamento de
Genética, Programa de Pós-Graduação em Genética, Curitiba, PR, Brazil
| | - Rafael Bueno Noleto
- Universidade Estadual do Paraná, Departamento de Biologia, União da
Vitória, PR, Brazil
| | - Matheus Azambuja
- Universidade Federal do Paraná, Centro Politécnico, Departamento de
Genética, Programa de Pós-Graduação em Genética, Curitiba, PR, Brazil
| | - Camilla Borges Gazolla
- Universidade Federal do Paraná, Centro Politécnico, Departamento de
Genética, Programa de Pós-Graduação em Genética, Curitiba, PR, Brazil
| | - Bianca Rocha Santos
- Universidade Estadual do Paraná, Departamento de Biologia, União da
Vitória, PR, Brazil
| | - Viviane Nogaroto
- Universidade Estadual de Ponta Grossa, Departamento de Biologia
Estrutural, Molecular e Genética, Ponta Grossa, PR, Brazil
| | - Marcelo Ricardo Vicari
- Universidade Federal do Paraná, Centro Politécnico, Departamento de
Genética, Programa de Pós-Graduação em Genética, Curitiba, PR, Brazil.,Universidade Estadual de Ponta Grossa, Departamento de Biologia
Estrutural, Molecular e Genética, Ponta Grossa, PR, Brazil
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36
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Sakthivel D, Brown-Suedel A, Bouchier-Hayes L. The role of the nucleolus in regulating the cell cycle and the DNA damage response. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 135:203-241. [PMID: 37061332 DOI: 10.1016/bs.apcsb.2023.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The nucleolus has long been perceived as the site for ribosome biogenesis, but numerous studies suggest that the nucleolus carefully sequesters crucial proteins involved in multiple cellular functions. Among these, the role of nucleolus in cell cycle regulation is the most evident. The nucleolus is the first responder of growth-related signals to mediate normal cell cycle progression. The nucleolus also senses different cellular stress insults by activating diverse pathways that arrest the cell cycle, promote DNA repair, or initiate apoptosis. Here, we review the emerging concepts on how the ribosomal and nonribosomal nucleolar proteins mediate such cellular effects.
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Chromatin localization of nucleophosmin organizes ribosome biogenesis. Mol Cell 2022; 82:4443-4457.e9. [PMID: 36423630 PMCID: PMC9949351 DOI: 10.1016/j.molcel.2022.10.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 09/01/2022] [Accepted: 10/28/2022] [Indexed: 11/24/2022]
Abstract
Ribosome biogenesis takes place in the nucleolus, a nuclear membrane-less organelle. Although well studied, it remains unknown how nascent ribosomal subunits separate from the central chromatin compartment and move to the outer granular component, where maturation occurs. We find that the Schizosaccharomyces pombe nucleophosmin-like protein Fkbp39 localizes to rDNA sites encoding the 60S subunit rRNA, and this localization contributes to its specific association with nascent 60S subunits. Fkbp39 dissociates from chromatin to bind nascent 60S subunits, causing the latter to partition away from chromatin and from nascent 40S subunits through liquid-liquid phase separation. In vivo, Fkbp39 binding directs the translocation of nascent 60S subunits toward the nucleophosmin-rich granular component. This process increases the efficiency of 60S subunit assembly, facilitating the incorporation of 60S RNA domain III. Thus, chromatin localization determines the specificity of nucleophosmin in sorting nascent ribosomal subunits and coordinates their movement into specialized assembly compartments within the nucleolus.
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38
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Regulation of RNA Polymerase I Stability and Function. Cancers (Basel) 2022; 14:cancers14235776. [PMID: 36497261 PMCID: PMC9737084 DOI: 10.3390/cancers14235776] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/21/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
RNA polymerase I is a highly processive enzyme with fast initiation and elongation rates. The structure of Pol I, with its in-built RNA cleavage ability and incorporation of subunits homologous to transcription factors, enables it to quickly and efficiently synthesize the enormous amount of rRNA required for ribosome biogenesis. Each step of Pol I transcription is carefully controlled. However, cancers have highjacked these control points to switch the enzyme, and its transcription, on permanently. While this provides an exceptional benefit to cancer cells, it also creates a potential cancer therapeutic vulnerability. We review the current research on the regulation of Pol I transcription, and we discuss chemical biology efforts to develop new targeted agents against this process. Lastly, we highlight challenges that have arisen from the introduction of agents with promiscuous mechanisms of action and provide examples of agents with specificity and selectivity against Pol I.
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39
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Mirceta M, Shum N, Schmidt MHM, Pearson CE. Fragile sites, chromosomal lesions, tandem repeats, and disease. Front Genet 2022; 13:985975. [PMID: 36468036 PMCID: PMC9714581 DOI: 10.3389/fgene.2022.985975] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/02/2022] [Indexed: 09/16/2023] Open
Abstract
Expanded tandem repeat DNAs are associated with various unusual chromosomal lesions, despiralizations, multi-branched inter-chromosomal associations, and fragile sites. Fragile sites cytogenetically manifest as localized gaps or discontinuities in chromosome structure and are an important genetic, biological, and health-related phenomena. Common fragile sites (∼230), present in most individuals, are induced by aphidicolin and can be associated with cancer; of the 27 molecularly-mapped common sites, none are associated with a particular DNA sequence motif. Rare fragile sites ( ≳ 40 known), ≤ 5% of the population (may be as few as a single individual), can be associated with neurodevelopmental disease. All 10 molecularly-mapped folate-sensitive fragile sites, the largest category of rare fragile sites, are caused by gene-specific CGG/CCG tandem repeat expansions that are aberrantly CpG methylated and include FRAXA, FRAXE, FRAXF, FRA2A, FRA7A, FRA10A, FRA11A, FRA11B, FRA12A, and FRA16A. The minisatellite-associated rare fragile sites, FRA10B, FRA16B, can be induced by AT-rich DNA-ligands or nucleotide analogs. Despiralized lesions and multi-branched inter-chromosomal associations at the heterochromatic satellite repeats of chromosomes 1, 9, 16 are inducible by de-methylating agents like 5-azadeoxycytidine and can spontaneously arise in patients with ICF syndrome (Immunodeficiency Centromeric instability and Facial anomalies) with mutations in genes regulating DNA methylation. ICF individuals have hypomethylated satellites I-III, alpha-satellites, and subtelomeric repeats. Ribosomal repeats and subtelomeric D4Z4 megasatellites/macrosatellites, are associated with chromosome location, fragility, and disease. Telomere repeats can also assume fragile sites. Dietary deficiencies of folate or vitamin B12, or drug insults are associated with megaloblastic and/or pernicious anemia, that display chromosomes with fragile sites. The recent discovery of many new tandem repeat expansion loci, with varied repeat motifs, where motif lengths can range from mono-nucleotides to megabase units, could be the molecular cause of new fragile sites, or other chromosomal lesions. This review focuses on repeat-associated fragility, covering their induction, cytogenetics, epigenetics, cell type specificity, genetic instability (repeat instability, micronuclei, deletions/rearrangements, and sister chromatid exchange), unusual heritability, disease association, and penetrance. Understanding tandem repeat-associated chromosomal fragile sites provides insight to chromosome structure, genome packaging, genetic instability, and disease.
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Affiliation(s)
- Mila Mirceta
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Natalie Shum
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Monika H. M. Schmidt
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Christopher E. Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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40
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Integration of Repeatomic and Cytogenetic Data on Satellite DNA for the Genome Analysis in the Genus Salvia (Lamiaceae). PLANTS 2022; 11:plants11172244. [PMID: 36079625 PMCID: PMC9460151 DOI: 10.3390/plants11172244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/25/2022] [Accepted: 08/25/2022] [Indexed: 11/17/2022]
Abstract
Within the complicated and controversial taxonomy of cosmopolitan genus Salvia L. (Lamiaceae) are valuable species Salvia officinalis L. and Salvia sclarea L., which are important for the pharmaceutical, ornamental horticulture, food, and perfume industries. Genome organization and chromosome structure of these essential oil species remain insufficiently studied. For the first time, the comparative repeatome analysis of S. officinalis and S. sclarea was performed using the obtained NGS data, RepeatExplorer/TAREAN pipelines and FISH-based chromosome mapping of the revealed satellite DNA families (satDNAs). In repeatomes of these species, LTR retrotransposons made up the majority of their repetitive DNA. Interspecific variations in genome abundance of Class I and Class II transposable elements, ribosomal DNA, and satellite DNA were revealed. Four (S. sclarea) and twelve (S. officinalis) putative satDNAs were identified. Based on patterns of chromosomal distribution of 45S rDNA; 5S rDNA and the revealed satDNAs, karyograms of S. officinalis and S. sclarea were constructed. Promising satDNAs which can be further used as chromosome markers to assess inter- and intraspecific chromosome variability in Salvia karyotypes were determined. The specific localization of homologous satDNA and 45S rDNA on chromosomes of the studied Salvia species confirmed their common origin, which is consistent with previously reported molecular phylogenetic data.
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41
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Ribosome-Directed Therapies in Cancer. Biomedicines 2022; 10:biomedicines10092088. [PMID: 36140189 PMCID: PMC9495564 DOI: 10.3390/biomedicines10092088] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/22/2022] [Accepted: 08/22/2022] [Indexed: 12/29/2022] Open
Abstract
The human ribosomes are the cellular machines that participate in protein synthesis, which is deeply affected during cancer transformation by different oncoproteins and is shown to provide cancer cell proliferation and therefore biomass. Cancer diseases are associated with an increase in ribosome biogenesis and mutation of ribosomal proteins. The ribosome represents an attractive anti-cancer therapy target and several strategies are used to identify specific drugs. Here we review the role of different drugs that may decrease ribosome biogenesis and cancer cell proliferation.
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First Insights on the Karyotype Diversification of the Endemic Malagasy Leaf-Toed Geckos (Squamata: Gekkonidae: Uroplatus). Animals (Basel) 2022; 12:ani12162054. [PMID: 36009644 PMCID: PMC9404452 DOI: 10.3390/ani12162054] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/01/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary The geckos of the genus Uroplatus include peculiar endemic species to Madagascar. Even though they have been the subject of several morphological and molecular studies, karyological analyses have been performed only on U. phantasticus, leaving the chromosomal diversity of the genus completely unexplored. In this study, we performed a preliminary molecular analysis and a comparative cytogenetic study providing the first karyotype description of eight species of Uroplatus and an assessment of their karyological variability. We found chromosome diversity in the species studied in terms of total chromosome number (2n = 34–38), localization of loci of Nucleolar Organizer Regions (NORs) (alternatively on the 2nd, 6th, 10th or 16th pair), heterochromatin composition and occurrence of heteromorphic sex chromosome pairs. Adding our newly generated data to those available from the literature, we show that in the genus Uroplatus, as well as in a larger group of phylogenetically related gecko genera, chromosome diversification mainly occurred toward a reduction in the chromosome number by means of chromosome fusions and translocation of NOR-bearing chromosomes. We also hypothesize that the diversification of sex chromosome systems occurred independently in different genera. Abstract We provide here the first karyotype description of eight Uroplatus species and a characterization of their chromosomal diversity. We performed a molecular taxonomic assessment of several Uroplatus samples using the mitochondrial 12S marker and a comparative cytogenetic analysis with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, +Chromomycin A3 (CMA3), +4′,6-diamidino-2-phenylindole (DAPI). We found chromosomal variability in terms of chromosome number (2n = 34–38), heterochromatin composition and number and localization of loci or Nucleolar Organizer Regions (NORs) (alternatively on the 2nd, 6th, 10th or 16th pair). Chromosome morphology is almost constant, with karyotypes composed of acrocentric chromosomes, gradually decreasing in length. C-banding evidenced a general low content of heterochromatin, mostly localized on pericentromeric and telomeric regions. Centromeric bands varied among the species studied, resulting in CMA3 positive and DAPI negative or positive to both fluorochromes. We also provide evidence of a first putative heteromorphic sex chromosome system in the genus. In fact, in U. alluaudi the 10th pair was highly heteromorphic, with a metacentric, largely heterochromatic W chromosome, which was much bigger than the Z. We propose an evolutionary scenario of chromosome reduction from 2n = 38 to 2n = 34, by means of translocations of microchromosomes on larger chromosomes (often involving the NOR-bearing microchromosomes). Adding our data to those available from the literature, we show that similar processes characterized the evolutionary radiation of a larger gecko clade. Finally, we hypothesize that sex chromosome diversification occurred independently in different genera.
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Zhang X, Jia X, Zhong B, Wei L, Li J, Zhang W, Fang H, Li Y, Lu Y, Wang X. Evaluating methylation of human ribosomal DNA at each CpG site reveals its utility for cancer detection using cell-free DNA. Brief Bioinform 2022; 23:6634225. [PMID: 35804466 DOI: 10.1093/bib/bbac278] [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: 04/11/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Ribosomal deoxyribonucleic acid (DNA) (rDNA) repeats are tandemly located on five acrocentric chromosomes with up to hundreds of copies in the human genome. DNA methylation, the most well-studied epigenetic mechanism, has been characterized for most genomic regions across various biological contexts. However, rDNA methylation patterns remain largely unexplored due to the repetitive structure. In this study, we designed a specific mapping strategy to investigate rDNA methylation patterns at each CpG site across various physiological and pathological processes. We found that CpG sites on rDNA could be categorized into two types. One is within or adjacent to transcribed regions; the other is distal to transcribed regions. The former shows highly variable methylation levels across samples, while the latter shows stable high methylation levels in normal tissues but severe hypomethylation in tumors. We further showed that rDNA methylation profiles in plasma cell-free DNA could be used as a biomarker for cancer detection. It shows good performances on public datasets, including colorectal cancer [area under the curve (AUC) = 0.85], lung cancer (AUC = 0.84), hepatocellular carcinoma (AUC = 0.91) and in-house generated hepatocellular carcinoma dataset (AUC = 0.96) even at low genome coverage (<1×). Taken together, these findings broaden our understanding of rDNA regulation and suggest the potential utility of rDNA methylation features as disease biomarkers.
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Affiliation(s)
- Xianglin Zhang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Xiaodong Jia
- Senior Department of Oncology, Fifth Medical Center of PLA General Hospital, Beijing 100039, China
| | - Bixi Zhong
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Lei Wei
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Jiaqi Li
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Wei Zhang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Huan Fang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Yanda Li
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
| | - Yinying Lu
- Comprehensive Liver Cancer Center, Fifth Medical Center of PLA General Hospital, Beijing 100039, China.,Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.,Guangdong Key Laboratory of Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Xiaowo Wang
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; Beijing National Research Center for Information Science and Technology; Department of Automation, Tsinghua University, Beijing 100084, China
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Temaj G, Saha S, Dragusha S, Ejupi V, Buttari B, Profumo E, Beqa L, Saso L. Ribosomopathies and cancer: pharmacological implications. Expert Rev Clin Pharmacol 2022; 15:729-746. [PMID: 35787725 DOI: 10.1080/17512433.2022.2098110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The ribosome is a ribonucleoprotein organelle responsible for protein synthesis, and its biogenesis is a highly coordinated process that involves many macromolecular components. Any acquired or inherited impairment in ribosome biogenesis or ribosomopathies is associated with the development of different cancers and rare genetic diseases. Interference with multiple steps of protein synthesis has been shown to promote tumor cell death. AREAS COVERED We discuss the current insights about impaired ribosome biogenesis and their secondary consequences on protein synthesis, transcriptional and translational responses, proteotoxic stress, and other metabolic pathways associated with cancer and rare diseases. Studies investigating the modulation of different therapeutic chemical entities targeting cancer in in vitro and in vivo models have also been detailed. EXPERT OPINION Despite the association between inherited mutations affecting ribosome biogenesis and cancer biology, the development of therapeutics targeting the essential cellular machinery has only started to emerge. New chemical entities should be designed to modulate different checkpoints (translating oncoproteins, dysregulation of specific ribosome-assembly machinery, ribosomal stress, and rewiring ribosomal functions). Although safe and effective therapies are lacking, consideration should also be given to using existing drugs alone or in combination for long-term safety, with known risks for feasibility in clinical trials and synergistic effects.
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Affiliation(s)
| | - Sarmistha Saha
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | | | - Valon Ejupi
- College UBT, Faculty of Pharmacy, Prishtina, Kosovo
| | - Brigitta Buttari
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | - Elisabetta Profumo
- Department of Cardiovascular, Endocrine-metabolic Diseases, and Aging, Italian National Institute of Health, Rome, Italy
| | - Lule Beqa
- College UBT, Faculty of Pharmacy, Prishtina, Kosovo
| | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Italy
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45
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Mora A, Huang X, Jauhari S, Jiang Q, Li X. Chromatin Hubs: A biological and computational outlook. Comput Struct Biotechnol J 2022; 20:3796-3813. [PMID: 35891791 PMCID: PMC9304431 DOI: 10.1016/j.csbj.2022.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/02/2022] [Accepted: 07/02/2022] [Indexed: 11/20/2022] Open
Abstract
This review discusses our current understanding of chromatin biology and bioinformatics under the unifying concept of “chromatin hubs.” The first part reviews the biology of chromatin hubs, including chromatin–chromatin interaction hubs, chromatin hubs at the nuclear periphery, hubs around macromolecules such as RNA polymerase or lncRNAs, and hubs around nuclear bodies such as the nucleolus or nuclear speckles. The second part reviews existing computational methods, including enhancer–promoter interaction prediction, network analysis, chromatin domain callers, transcription factory predictors, and multi-way interaction analysis. We introduce an integrated model that makes sense of the existing evidence. Understanding chromatin hubs may allow us (i) to explain long-unsolved biological questions such as interaction specificity and redundancy of mechanisms, (ii) to develop more realistic kinetic and functional predictions, and (iii) to explain the etiology of genomic disease.
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Affiliation(s)
- Antonio Mora
- Joint School of Life Sciences, Guangzhou Medical University and Guangzhou Institutes of Biomedicine and Health (Chinese Academy of Sciences), Guangzhou 511436, PR China
- Corresponding authors.
| | - Xiaowei Huang
- Joint School of Life Sciences, Guangzhou Medical University and Guangzhou Institutes of Biomedicine and Health (Chinese Academy of Sciences), Guangzhou 511436, PR China
| | - Shaurya Jauhari
- Joint School of Life Sciences, Guangzhou Medical University and Guangzhou Institutes of Biomedicine and Health (Chinese Academy of Sciences), Guangzhou 511436, PR China
| | - Qin Jiang
- Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210000, PR China
| | - Xuri Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, and Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, PR China
- Corresponding authors.
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46
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Wei C, Jia L, Huang X, Tan J, Wang M, Niu J, Hou Y, Sun J, Zeng P, Wang J, Qing L, Ma L, Liu X, Tang X, Li F, Jiang S, Liu J, Li T, Fan L, Sun Y, Gao J, Li C, Ding J. CTCF organizes inter-A compartment interactions through RYBP-dependent phase separation. Cell Res 2022; 32:744-760. [PMID: 35768498 PMCID: PMC9343660 DOI: 10.1038/s41422-022-00676-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/10/2022] [Indexed: 12/13/2022] Open
Abstract
Chromatin is spatially organized into three-dimensional structures at different levels including A/B compartments, topologically associating domains and loops. The canonical CTCF-mediated loop extrusion model can explain the formation of loops. However, the organization mechanisms underlying long-range chromatin interactions such as interactions between A-A compartments are still poorly understood. Here we show that different from the canonical loop extrusion model, RYBP-mediated phase separation of CTCF organizes inter-A compartment interactions. Based on this model, we designed and verified an induced CTCF phase separation system in embryonic stem cells (ESCs), which facilitated inter-A compartment interactions, improved self-renewal of ESCs and inhibited their differentiation toward neural progenitor cells. These findings support a novel and non-canonical role of CTCF in organizing long-range chromatin interactions via phase separation.
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Affiliation(s)
- Chao Wei
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Lumeng Jia
- School of Life Sciences, Peking University, Beijing, China
| | - Xiaona Huang
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jin Tan
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Mulan Wang
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jing Niu
- School of Medicine, Tsinghua University, Beijing, China
| | - Yingping Hou
- Peking-Tsinghua Center for Life Sciences; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Jun Sun
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Pengguihang Zeng
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong, China
| | - Jia Wang
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Li Qing
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Lin Ma
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xinyi Liu
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiuxiao Tang
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Fenjie Li
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Department of Pediatric Surgery, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Shaoshuai Jiang
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jingxin Liu
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China.,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Tingting Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Institute of Basic Medical Sciences, Beijing, China
| | - Lili Fan
- Guangzhou Key Laboratory of Formula-Pattern of Traditional Chinese Medicine, School of Traditional Chinese Medicine, Jinan University, Guangzhou, Guangdong, China
| | - Yujie Sun
- School of Life Sciences, Peking University, Beijing, China.,State Key Laboratory of Membrane Biology, Biomedical pioneering innovation center (BIOPIC), Peking University, Beijing, China
| | - Juntao Gao
- MOE Key Laboratory of Bioinformatics; Bioinformatics Division, BNRist; Department of Automation; Center for Synthetic & Systems Biology, Tsinghua University, Beijing, China
| | - Cheng Li
- School of Life Sciences, Peking University, Beijing, China. .,Center for Bioinformatics, Center for Statistical Science, Peking University, Beijing, China.
| | - Junjun Ding
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China. .,Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, China. .,Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.
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Evaluation of Tumor Grade and Proliferation Indices before and after Short-Course Anti-Inflammatory Prednisone Therapy in Canine Cutaneous Mast Cell Tumors: A Pilot Study. Vet Sci 2022; 9:vetsci9060277. [PMID: 35737330 PMCID: PMC9227510 DOI: 10.3390/vetsci9060277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 11/30/2022] Open
Abstract
Glucocorticoid administration is a common clinical practice that attempts to decrease the inflammation associated with and improve the resectability of canine mast cell tumors (MCTs). However, the impact of neoadjuvant glucocorticoids on the histological features and proliferation indices of canine MCTs is unknown. The objective of this study was to evaluate changes in tumor grade, mitotic count, Ki67, AgNOR, and AgNORxKi67 scores following short-course anti-inflammatory neoadjuvant prednisone in canine patients with MCTs. This was a prospective single-arm pilot study. Client-owned dogs with treatment-naïve cytologically confirmed MCTs were enrolled. Patients underwent an initial incisional biopsy followed by a 10–14-day course of anti-inflammatory prednisone and surgical resection. All histological samples were randomized, masked, and evaluated by a single pathologist. Unstained paired pre- and post-treatment samples were submitted to a commercial laboratory for Ki67 and AgNOR immunohistochemical analysis. There were 11 dogs enrolled with 11 tumors. There were no statistical differences between the pre- and post-treatment histological parameters of mitotic index, Ki67, AgNOR, or Ki67xAgNOR. There were no clinically significant alterations between pre-treatment and post-treatment in the assignment of tumor grades. A short course of anti-inflammatory prednisone does not appear to alter the histological parameters that affect grade determination or significantly alter the proliferation indices in canine MCTs.
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48
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Lee DSW, Strom AR, Brangwynne CP. The mechanobiology of nuclear phase separation. APL Bioeng 2022; 6:021503. [PMID: 35540725 PMCID: PMC9054271 DOI: 10.1063/5.0083286] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/19/2022] [Indexed: 02/06/2023] Open
Abstract
The cell nucleus can be thought of as a complex, dynamic, living material, which functions to organize and protect the genome and coordinate gene expression. These functions are achieved via intricate mechanical and biochemical interactions among its myriad components, including the nuclear lamina, nuclear bodies, and the chromatin itself. While the biophysical organization of the nuclear lamina and chromatin have been thoroughly studied, the concept that liquid-liquid phase separation and related phase transitions play a role in establishing nuclear structure has emerged only recently. Phase transitions are likely to be intimately coupled to the mechanobiology of structural elements in the nucleus, but their interplay with one another is still not understood. Here, we review recent developments on the role of phase separation and mechanics in nuclear organization and discuss the functional implications in cell physiology and disease states.
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Affiliation(s)
- Daniel S. W. Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544, USA
| | - Amy R. Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Srinivasan D, Shisode T, Shrinet J, Fraser P. Chromosome organization through the cell cycle at a glance. J Cell Sci 2022; 135:275498. [PMID: 35608019 DOI: 10.1242/jcs.244004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genome organization and the three-dimensional folding of chromosomes are now seen as major contributors to nearly all nuclear functions including gene regulation, replication and repair. Recent studies have shown that in addition to the dramatic metamorphoses in chromosome conformation associated with entry to, and exit from mitosis, chromosomes undergo continual conformational changes throughout interphase with differential dynamics in loop structure, topological domains, compartments and lamina-associated domains. Understanding and accounting for these cell-cycle-dependent conformational changes is essential for the interpretation of data from a growing array of powerful molecular techniques to investigate genome conformation function, and to identify the molecules and mechanisms that drive chromosome conformational changes. In this Cell Science at a Glance article and the accompanying poster, we review Hi-C and microscopy studies describing cell-cycle-dependent conformational changes in chromosome structure.
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Affiliation(s)
- Divyaa Srinivasan
- Department of Biological Science, Florida State University, Tallahassee, FL 32304, USA
| | - Tarak Shisode
- Department of Biological Science, Florida State University, Tallahassee, FL 32304, USA
| | - Jatin Shrinet
- Department of Biological Science, Florida State University, Tallahassee, FL 32304, USA
| | - Peter Fraser
- Department of Biological Science, Florida State University, Tallahassee, FL 32304, USA
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50
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Amosova AV, Yurkevich OY, Bolsheva NL, Samatadze TE, Zoshchuk SA, Muravenko OV. Repeatome Analyses and Satellite DNA Chromosome Patterns in Deschampsia sukatschewii, D. cespitosa, and D. antarctica (Poaceae). Genes (Basel) 2022; 13:genes13050762. [PMID: 35627148 PMCID: PMC9141916 DOI: 10.3390/genes13050762] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 02/05/2023] Open
Abstract
Subpolar and polar ecotypes of Deschampsia sukatschewii (Popl.) Roshev, D. cespitosa (L.) P. Beauv, and D. antarctica E. Desv. are well adapted to stressful environmental conditions, which make them useful model plants for genetic research and breeding. For the first time, the comparative repeatome analyses of subpolar and polar D. sukatschewii, D. cespitosa, and D. antarctica was performed using RepeatExplorer/TAREAN pipelines and FISH-based chromosomal mapping of the identified satellite DNA families (satDNAs). In the studied species, mobile genetic elements of class 1 made up the majority of their repetitive DNA; interspecific variations in the total amount of Ty3/Gypsy and Ty1/Copia retroelements, DNA transposons, ribosomal, and satellite DNA were revealed; 12–18 high confident and 7–9 low confident putative satDNAs were identified. According to BLAST, most D. sukatschewii satDNAs demonstrated sequence similarity with satDNAs of D. antarctica and D. cespitosa indicating their common origin. Chromosomal mapping of 45S rDNA, 5S rDNA, and satDNAs of D. sukatschewii allowed us to construct the species karyograms and detect new molecular chromosome markers important for Deschampsia species. Our findings confirmed that genomes of D. sukatschewii and D. cespitosa were more closely related compared to D. antarctica according to repeatome composition and patterns of satDNA chromosomal distribution.
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