1
|
Macdonald E, Whibley A, Waters PD, Patel H, Edwards RJ, Ganley ARD. Origin and maintenance of large ribosomal RNA gene repeat size in mammals. Genetics 2024; 228:iyae121. [PMID: 39044674 PMCID: PMC11373518 DOI: 10.1093/genetics/iyae121] [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: 06/14/2024] [Revised: 07/15/2024] [Accepted: 07/16/2024] [Indexed: 07/25/2024] Open
Abstract
The genes encoding ribosomal RNA are highly conserved across life and in almost all eukaryotes are present in large tandem repeat arrays called the rDNA. rDNA repeat unit size is conserved across most eukaryotes but has expanded dramatically in mammals, principally through the expansion of the intergenic spacer region that separates adjacent rRNA coding regions. Here, we used long-read sequence data from representatives of the major amniote lineages to determine where in amniote evolution rDNA unit size increased. We find that amniote rDNA unit sizes fall into two narrow size classes: "normal" (∼11-20 kb) in all amniotes except monotreme, marsupial, and eutherian mammals, which have "large" (∼35-45 kb) sizes. We confirm that increases in intergenic spacer length explain much of this mammalian size increase. However, in stark contrast to the uniformity of mammalian rDNA unit size, mammalian intergenic spacers differ greatly in sequence. These results suggest a large increase in intergenic spacer size occurred in a mammalian ancestor and has been maintained despite substantial sequence changes over the course of mammalian evolution. This points to a previously unrecognized constraint on the length of the intergenic spacer, a region that was thought to be largely neutral. We finish by speculating on possible causes of this constraint.
Collapse
Affiliation(s)
- Emma Macdonald
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Annabel Whibley
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Grapevine Improvement, Bragato Research Institute, RFH Building, Engineering Drive, Lincoln University, Lincoln 7647, New Zealand
| | - Paul D Waters
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Chancellery Walk, Kensington, NSW 2033, Australia
| | - Hardip Patel
- John Curtin School of Medical Research, Australian National University, 131 Garran Rd, Acton, ACT 2601, Australia
| | - Richard J Edwards
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Chancellery Walk, Kensington, NSW 2033, Australia
- Minderoo OceanOmics Centre at UWA, UWA Oceans Institute, University of Western Australia, Crawley WA 6009, Australia
| | - Austen R D Ganley
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Digital Life Institute, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| |
Collapse
|
2
|
Sibai DS, Tremblay MG, Lessard F, Tav C, Sabourin-Félix M, Robinson M, Moss T. TTF1 control of LncRNA synthesis delineates a tumor suppressor pathway directly regulating the ribosomal RNA genes. J Cell Physiol 2024; 239:e31303. [PMID: 38764354 DOI: 10.1002/jcp.31303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/21/2024]
Abstract
The tumor suppressor p14/19ARF regulates ribosomal RNA (rRNA) synthesis by controlling the nucleolar localization of Transcription Termination Factor 1 (TTF1). However, the role played by TTF1 in regulating the rRNA genes and in potentially controlling growth has remained unclear. We now show that TTF1 expression regulates cell growth by determining the cellular complement of ribosomes. Unexpectedly, it achieves this by acting as a "roadblock" to synthesis of the noncoding LncRNA and pRNA that we show are generated from the "Spacer Promoter" duplications present upstream of the 47S pre-rRNA promoter on the mouse and human ribosomal RNA genes. Unexpectedly, the endogenous generation of these noncoding RNAs does not induce CpG methylation or gene silencing. Rather, it acts in cis to suppress 47S preinitiation complex formation and hence de novo pre-rRNA synthesis by a mechanism reminiscent of promoter interference or occlusion. Taken together, our data delineate a pathway from p19ARF to cell growth suppression via the regulation of ribosome biogenesis by noncoding RNAs and validate a key cellular growth law in mammalian cells.
Collapse
Affiliation(s)
- Dany S Sibai
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec City, Quebec, Canada
- Cancer Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Michel G Tremblay
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Frédéric Lessard
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Christophe Tav
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec City, Quebec, Canada
- Cancer Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Marianne Sabourin-Félix
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Mark Robinson
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Tom Moss
- St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Laval University, Quebec City, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec City, Quebec, Canada
- Cancer Research Centre, Laval University, Quebec City, Quebec, Canada
| |
Collapse
|
3
|
Yang F, Guo X, Bao Y, Li R. The role of ribosomal DNA methylation in embryonic development, aging and diseases. Epigenetics Chromatin 2024; 17:23. [PMID: 39085958 PMCID: PMC11290161 DOI: 10.1186/s13072-024-00548-4] [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: 05/27/2024] [Accepted: 07/11/2024] [Indexed: 08/02/2024] Open
Abstract
The ribosomal DNA (rDNA) constitutes a remarkably conserved DNA sequence within species, located in the area of the nucleolus, and responsible for coding three major types of rRNAs (18S, 5.8S and 28S). While historical investigations into rDNA focused on its structure and coding capabilities, recent research has turned to explore its functional roles in various biological processes. In this review, we summarize the main findings of rDNA methylation with embryonic development, aging and diseases in multiple species, including epigenetic alterations, related biological processes and potential applications of rDNA methylation. We present an overview of current related research and identify gaps in this field.
Collapse
Affiliation(s)
- Fei Yang
- National Genomics Data Center, China National Center for Bioinformation, Beijing, 100101, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xutong Guo
- National Genomics Data Center, China National Center for Bioinformation, Beijing, 100101, China
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiming Bao
- National Genomics Data Center, China National Center for Bioinformation, Beijing, 100101, China.
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Rujiao Li
- National Genomics Data Center, China National Center for Bioinformation, Beijing, 100101, China.
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
| |
Collapse
|
4
|
Paralkar VR. Transcription factor regulation of ribosomal RNA in hematopoiesis. Curr Opin Hematol 2024; 31:199-206. [PMID: 38568093 PMCID: PMC11139577 DOI: 10.1097/moh.0000000000000816] [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: 04/09/2024]
Abstract
PURPOSE OF REVIEW Ribosomal RNAs (rRNAs) are transcribed within nucleoli from rDNA repeats by RNA Polymerase I (Pol I). There is variation in rRNA transcription rates across the hematopoietic tree, and leukemic blast cells have prominent nucleoli, indicating abundant ribosome biogenesis. The mechanisms underlying these variations are poorly understood. The purpose of this review is to summarize findings of rDNA binding and Pol I regulation by hematopoietic transcription factors. RECENT FINDINGS Our group recently used custom genome assemblies optimized for human and mouse rDNA mapping to map nearly 2200 ChIP-Seq datasets for nearly 250 factors to rDNA, allowing us to identify conserved occupancy patterns for multiple transcription factors. We confirmed known rDNA occupancy of MYC and RUNX factors, and identified new binding sites for CEBP factors, IRF factors, and SPI1 at canonical motif sequences. We also showed that CEBPA degradation rapidly leads to reduced Pol I occupancy and nascent rRNA in mouse myeloid cells. SUMMARY We propose that a number of hematopoietic transcription factors bind rDNA and potentially regulate rRNA transcription. Our model has implications for normal and malignant hematopoiesis. This review summarizes the literature, and outlines experimental considerations to bear in mind while dissecting transcription factor roles on rDNA.
Collapse
Affiliation(s)
- Vikram R. Paralkar
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
- Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| |
Collapse
|
5
|
Kim JH, Nagaraja R, Ogurtsov AY, Noskov VN, Liskovykh M, Lee HS, Hori Y, Kobayashi T, Hunter K, Schlessinger D, Kouprina N, Shabalina SA, Larionov V. Comparative analysis and classification of highly divergent mouse rDNA units based on their intergenic spacer (IGS) variability. NAR Genom Bioinform 2024; 6:lqae070. [PMID: 38881577 PMCID: PMC11177557 DOI: 10.1093/nargab/lqae070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/20/2024] [Accepted: 06/05/2024] [Indexed: 06/18/2024] Open
Abstract
Ribosomal DNA (rDNA) repeat units are organized into tandem clusters in eukaryotic cells. In mice, these clusters are located on at least eight chromosomes and show extensive variation in the number of repeats between mouse genomes. To analyze intra- and inter-genomic variation of mouse rDNA repeats, we selectively isolated 25 individual rDNA units using Transformation-Associated Recombination (TAR) cloning. Long-read sequencing and subsequent comparative sequence analysis revealed that each full-length unit comprises an intergenic spacer (IGS) and a ∼13.4 kb long transcribed region encoding the three rRNAs, but with substantial variability in rDNA unit size, ranging from ∼35 to ∼46 kb. Within the transcribed regions of rDNA units, we found 209 variants, 70 of which are in external transcribed spacers (ETSs); but the rDNA size differences are driven primarily by IGS size heterogeneity, due to indels containing repetitive elements and some functional signals such as enhancers. Further evolutionary analysis categorized rDNA units into distinct clusters with characteristic IGS lengths; numbers of enhancers; and presence/absence of two common SNPs in promoter regions, one of which is located within promoter (p)RNA and may influence pRNA folding stability. These characteristic features of IGSs also correlated significantly with 5'ETS variant patterns described previously and associated with differential expression of rDNA units. Our results suggest that variant rDNA units are differentially regulated and open a route to investigate the role of rDNA variation on nucleolar formation and possible associations with pathology.
Collapse
Affiliation(s)
- Jung-Hyun Kim
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| | - Ramaiah Nagaraja
- National Institute of Aging, Laboratory of Genetics and Genomics, Baltimore, MD, USA
| | - Alexey Y Ogurtsov
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - Vladimir N Noskov
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| | - Mikhail Liskovykh
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| | - Hee-Sheung Lee
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| | - Yutaro Hori
- The University of Tokyo, Laboratory of Genome Regeneration, Tokyo 113-0032, Japan
| | - Takehiko Kobayashi
- The University of Tokyo, Laboratory of Genome Regeneration, Tokyo 113-0032, Japan
| | - Kent Hunter
- National Cancer Institute, Laboratory of Cancer Biology and Genetics, Bethesda, MD, USA
| | - David Schlessinger
- National Institute of Aging, Laboratory of Genetics and Genomics, Baltimore, MD, USA
| | - Natalay Kouprina
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - Vladimir Larionov
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD, USA
| |
Collapse
|
6
|
Sandoval R, Dilsavor CN, Grishanina NR, Patel V, Zamudio JR. Mammalian RNAi represses pericentromeric lncRNAs to maintain genome stability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593425. [PMID: 38765997 PMCID: PMC11100815 DOI: 10.1101/2024.05.09.593425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Mammalian pericentromeric tandem repeats produce long noncoding RNAs (lncRNAs) that are dysregulated in cancer and linked to genomic instability. Identifying the basic molecular characteristics of these lncRNAs and their regulation is important to understanding their biological function. Here, we determine that the Argonaute (Ago) proteins of the RNA interference (RNAi) pathway directly and uniformly repress bidirectional pericentromeric lncRNAs in a Dicer-dependent manner in mouse embryonic and adult stem cells. Ago-dependent and Dicer-dependent autoregulatory small RNAs were identified within pericentromeric lncRNA degradation intermediates. We develop an RNase H cleavage assay to determine the relative proportions and lengths of the pericentromeric lncRNA targets. We find that 5'-phosphate and non-polyadenylated bidirectional pericentromeric lncRNAs are expressed at similar proportions. These lncRNAs can span up to 9 repeats, with transcription from the reverse strand template yielding the longer products. Using pericentromeric repeat RNA reporters, we determine that Ago represses pericentromeric lncRNAs after S phase transcription. Upon loss of Ago, pericentromeric lncRNA dysregulation results in delayed cell cycle progression, a defective mitotic spindle assembly checkpoint (SAC) and genomic instability. These results show that an evolutionarily conserved Ago activity at pericentromeres contributes to mammalian genome stability.
Collapse
|
7
|
Moss T, LeDoux MS, Crane-Robinson C. HMG-boxes, ribosomopathies and neurodegenerative disease. Front Genet 2023; 14:1225832. [PMID: 37600660 PMCID: PMC10435976 DOI: 10.3389/fgene.2023.1225832] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
The UBTF E210K neuroregression syndrome is a predominantly neurological disorder caused by recurrent de novo dominant variants in Upstream Binding Factor, that is, essential for transcription of the ribosomal RNA genes. This unusual form of ribosomopathy is characterized by a slow decline in cognition, behavior, and sensorimotor functioning during the critical period of development. UBTF (or UBF) is a multi-HMGB-box protein that acts both as an epigenetic factor to establish "open" chromatin on the ribosomal genes and as a basal transcription factor in their RNA Polymerase I transcription. Here we review the possible mechanistic connections between the UBTF variants, ribosomal RNA gene transcription and the neuroregression syndrome, and suggest that DNA topology may play an important role.
Collapse
Affiliation(s)
- Tom Moss
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, QC, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, QC, Canada
| | - Mark S. LeDoux
- Department of Psychology, University of Memphis, Memphis, TN, United States
- Veracity Neuroscience LLC, Memphis, TN, United States
| | - Colyn Crane-Robinson
- Biophysics Laboratories, School of Biology, University of Portsmouth, Portsmouth, United Kingdom
| |
Collapse
|
8
|
George SS, Pimkin M, Paralkar VR. Construction and validation of customized genomes for human and mouse ribosomal DNA mapping. J Biol Chem 2023; 299:104766. [PMID: 37121547 PMCID: PMC10245113 DOI: 10.1016/j.jbc.2023.104766] [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: 02/26/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/02/2023] Open
Abstract
rRNAs are transcribed from ribosomal DNA (rDNA) repeats, the most intensively transcribed loci in the genome. Due to their repetitive nature, there is a lack of genome assemblies suitable for rDNA mapping, creating a vacuum in our understanding of how the most abundant RNA in the cell is regulated. Our recent work revealed binding of numerous mammalian transcription and chromatin factors to rDNA. Several of these factors were known to play critical roles in development, tissue function, and malignancy, but their potential roles in rDNA regulation remained unexplored. This demonstrated the blind spot into which rDNA has fallen in genetic and epigenetic studies and highlighted an unmet need for public rDNA-optimized genome assemblies. Here, we customized five human and mouse assemblies-hg19 (GRCh37), hg38 (GRCh38), hs1 (T2T-CHM13), mm10 (GRCm38), and mm39 (GRCm39)-to render them suitable for rDNA mapping. The standard builds of these genomes contain numerous fragmented or repetitive rDNA loci. We identified and masked all rDNA-like regions, added a single rDNA reference sequence of the appropriate species as a ∼45 kb chromosome designated "chromosome R," and created annotation files to aid visualization of rDNA features in browser tracks. We validated these customized genomes for mapping of known rDNA-binding proteins and present a simple workflow for mapping chromatin immunoprecipitation-sequencing datasets. Customized genome assemblies, annotation files, positive and negative control tracks, and Snapgene files of standard rDNA reference sequences have been deposited to GitHub. These resources make rDNA mapping and visualization more readily accessible to a broad audience.
Collapse
Affiliation(s)
- Subin S George
- Institute for Biomedical Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Maxim Pimkin
- Cancer and Blood Disorders Center, Harvard Medical School, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, Massachusetts, USA
| | - Vikram R Paralkar
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA; Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
| |
Collapse
|
9
|
Dalíková M, Provazníková I, Provazník J, Grof-Tisza P, Pepi A, Nguyen P. The Role of Repetitive Sequences in Repatterning of Major Ribosomal DNA Clusters in Lepidoptera. Genome Biol Evol 2023; 15:evad090. [PMID: 37226278 PMCID: PMC10257491 DOI: 10.1093/gbe/evad090] [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] [Revised: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 05/26/2023] Open
Abstract
Genes for major ribosomal RNAs (rDNA) are present in multiple copies mainly organized in tandem arrays. The number and position of rDNA loci can change dynamically and their repatterning is presumably driven by other repetitive sequences. We explored a peculiar rDNA organization in several representatives of Lepidoptera with either extremely large or numerous rDNA clusters. We combined molecular cytogenetics with analyses of second- and third-generation sequencing data to show that rDNA spreads as a transcription unit and reveal association between rDNA and various repeats. Furthermore, we performed comparative long read analyses among the species with derived rDNA distribution and moths with a single rDNA locus, which is considered ancestral. Our results suggest that satellite arrays, rather than mobile elements, facilitate homology-mediated spread of rDNA via either integration of extrachromosomal rDNA circles or ectopic recombination. The latter arguably better explains preferential spread of rDNA into terminal regions of lepidopteran chromosomes as efficiency of ectopic recombination depends on the proximity of homologous sequences to telomeres.
Collapse
Affiliation(s)
- Martina Dalíková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| | - Irena Provazníková
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan Provazník
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Patrick Grof-Tisza
- Institute of Biology, Laboratory of Evolutionary Entomology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Adam Pepi
- Department of Biology, Tufts University
| | - Petr Nguyen
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre CAS, České Budějovice, Czech Republic
| |
Collapse
|
10
|
Antony C, George SS, Blum J, Somers P, Thorsheim CL, Wu-Corts DJ, Ai Y, Gao L, Lv K, Tremblay MG, Moss T, Tan K, Wilusz JE, Ganley ARD, Pimkin M, Paralkar VR. Control of ribosomal RNA synthesis by hematopoietic transcription factors. Mol Cell 2022; 82:3826-3839.e9. [PMID: 36113481 PMCID: PMC9588704 DOI: 10.1016/j.molcel.2022.08.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/23/2022] [Accepted: 08/23/2022] [Indexed: 11/19/2022]
Abstract
Ribosomal RNAs (rRNAs) are the most abundant cellular RNAs, and their synthesis from rDNA repeats by RNA polymerase I accounts for the bulk of all transcription. Despite substantial variation in rRNA transcription rates across cell types, little is known about cell-type-specific factors that bind rDNA and regulate rRNA transcription to meet tissue-specific needs. Using hematopoiesis as a model system, we mapped about 2,200 ChIP-seq datasets for 250 transcription factors (TFs) and chromatin proteins to human and mouse rDNA and identified robust binding of multiple TF families to canonical TF motifs on rDNA. Using a 47S-FISH-Flow assay developed for nascent rRNA quantification, we demonstrated that targeted degradation of C/EBP alpha (CEBPA), a critical hematopoietic TF with conserved rDNA binding, caused rapid reduction in rRNA transcription due to reduced RNA Pol I occupancy. Our work identifies numerous potential rRNA regulators and provides a template for dissection of TF roles in rRNA transcription.
Collapse
Affiliation(s)
- Charles Antony
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Subin S George
- Institute for Biomedical Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Justin Blum
- The College of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Patrick Somers
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Chelsea L Thorsheim
- Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Dexter J Wu-Corts
- The College of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yuxi Ai
- Biochemistry and Molecular Biophysics Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Long Gao
- Beijing Advanced Innovation Center for Genomics (ICG) & Biomedical Pioneering Innovation Center (BIOPIC), Peking University, Beijing 100871, China
| | - Kaosheng Lv
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Michel G Tremblay
- Laboratory of Growth and Development, St Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre (CRCHU de Québec-Université Laval), Québec, QC G1R 3S3, Canada
| | - Tom Moss
- Laboratory of Growth and Development, St Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre (CRCHU de Québec-Université Laval), Québec, QC G1R 3S3, Canada; Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University, Québec, QC G1V 0A6, Canada
| | - Kai Tan
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Austen R D Ganley
- School of Biological Sciences, University of Auckland, Auckland 0623, New Zealand; Digital Life Institute, University of Auckland, Auckland 0632, New Zealand
| | - Maxim Pimkin
- Cancer and Blood Disorders Center, Dana-Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Vikram R Paralkar
- Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| |
Collapse
|
11
|
Wu D. Mouse Oocytes, A Complex Single Cell Transcriptome. Front Cell Dev Biol 2022; 10:827937. [PMID: 35321242 PMCID: PMC8935041 DOI: 10.3389/fcell.2022.827937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
Germinal vesicle (GV) stage is a critical transition point from growth to maturation in mammalian oocyte development. During the following meiotic maturation, active RNA degradation and absence of transcription significantly reprofile the oocyte transcriptome to determine oocyte quality. Oocyte RNA-seq has revealed transcriptome differences between two defined phases of GV stage, namely non-surrounded nucleolus (NSN) and surrounded nucleolus (SN) phases. In addition, oocyte RNA-seq has identified a variety of dysregulated genes upon genetic mutation or environmental perturbation. Historically, due to the low amount of RNA per oocyte, a few (20–200) oocytes were needed for a regular library construction in bulk RNA-seq. In recent years, development of single cell sequencing allows detailing the transcriptome of individual oocytes. Here in this study, different RNA-seq datasets from single and bulk of mouse oocytes are compared, and single oocyte RNA-seq (soRNA-seq) shows higher reproducibility. In addition, soRNA-seq better illustrates developmental progression of GV oocytes, revealing more complex gene changes than traditional views. Specially, an elevated level of ribosomal RNA 5′-ETS (5′ external transcribed spacer) has been shown to highly correlate with SN property. This study further demonstrates that UMI (unique molecular identifiers) based and other deduplication methods are limited in their ability to improve the precision of the soRNA-seq datasets. Finally, this study proposes that external spike-in molecules are useful for normalizing samples of different transcriptome sizes. A list of stable genes has been identified during oocyte maturation that are comparable to external spike-in molecules. These findings highlight the advantage of soRNA-seq, and have established ways for better clustering and cross-stage normalization, which can provide more insight into the biological features of oocyte maturation.
Collapse
|
12
|
Luttermann T, Rückert C, Wibberg D, Busche T, Schwarzhans JP, Friehs K, Kalinowski J. Establishment of a near-contiguous genome sequence of the citric acid producing yeast Yarrowia lipolytica DSM 3286 with resolution of rDNA clusters and telomeres. NAR Genom Bioinform 2021; 3:lqab085. [PMID: 34661101 PMCID: PMC8515841 DOI: 10.1093/nargab/lqab085] [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: 12/22/2020] [Revised: 09/01/2021] [Accepted: 10/13/2021] [Indexed: 11/29/2022] Open
Abstract
Yarrowia lipolytica is an oleaginous yeast that is particularly suitable for the sustainable production of secondary metabolites. The genome of this yeast is characterized by its relatively large size and its high number of different rDNA clusters located in its telomeric regions. However, due to the presence of long repetitive elements in the sub-telomeric regions, rDNA clusters and telomeres are missing in current genome assemblies of Y. lipolytica. Here, we present the near-contiguous genome sequence of the biotechnologically relevant strain DSM 3286. We employed a hybrid assembly strategy combining Illumina and nanopore sequencing reads to integrate all six rDNA clusters as well as telomeric repeats into the genome sequence. By fine-tuning of DNA isolation and library preparation protocols, we were able to create ultra-long reads that not only contained multiples of mitochondrial genomes but also shed light on the inter- and intra-chromosomal diversity of rDNA cluster types. We show that there are ten different rDNA units present in this strain that additionally appear in a predefined order in a cluster. Based on single reads, we also demonstrate that the number of rDNA repeats in a specific cluster varies from cell to cell within a population.
Collapse
Affiliation(s)
- Tobias Luttermann
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Christian Rückert
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Daniel Wibberg
- Genome Research of Industrial Microorganisms, Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Tobias Busche
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| | | | - Karl Friehs
- Fermentation Engineering, Bielefeld University, Bielefeld, NRW 33615, Germany
| | - Jörn Kalinowski
- Microbial Genomics and Biotechnology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, NRW 33615, Germany
| |
Collapse
|
13
|
Lambert M, Benmoussa A, Diallo I, Ouellet-Boutin K, Dorval V, Majeau N, Joly-Beauparlant C, Droit A, Bergeron A, Têtu B, Fradet Y, Pouliot F, Provost P. Identification of Abundant and Functional dodecaRNAs (doRNAs) Derived from Ribosomal RNA. Int J Mol Sci 2021; 22:9757. [PMID: 34575920 PMCID: PMC8467515 DOI: 10.3390/ijms22189757] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/02/2021] [Accepted: 09/05/2021] [Indexed: 12/17/2022] Open
Abstract
Using a modified RNA-sequencing (RNA-seq) approach, we discovered a new family of unusually short RNAs mapping to ribosomal RNA 5.8S, which we named dodecaRNAs (doRNAs), according to the number of core nucleotides (12 nt) their members contain. Using a new quantitative detection method that we developed, we confirmed our RNA-seq data and determined that the minimal core doRNA sequence and its 13-nt variant C-doRNA (doRNA with a 5' Cytosine) are the two most abundant doRNAs, which, together, may outnumber microRNAs. The C-doRNA/doRNA ratio is stable within species but differed between species. doRNA and C-doRNA are mainly cytoplasmic and interact with heterogeneous nuclear ribonucleoproteins (hnRNP) A0, A1 and A2B1, but not Argonaute 2. Reporter gene activity assays suggest that C-doRNA may function as a regulator of Annexin II receptor (AXIIR) expression. doRNAs are differentially expressed in prostate cancer cells/tissues and may control cell migration. These findings suggest that unusually short RNAs may be more abundant and important than previously thought.
Collapse
Affiliation(s)
- Marine Lambert
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Department of Microbiology, Infectious Diseases and Immunology, Université Laval, Quebec City, QC G1V 4G2, Canada
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Abderrahim Benmoussa
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Department of Microbiology, Infectious Diseases and Immunology, Université Laval, Quebec City, QC G1V 4G2, Canada
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Idrissa Diallo
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Department of Microbiology, Infectious Diseases and Immunology, Université Laval, Quebec City, QC G1V 4G2, Canada
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Katheryn Ouellet-Boutin
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Department of Microbiology, Infectious Diseases and Immunology, Université Laval, Quebec City, QC G1V 4G2, Canada
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Véronique Dorval
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
| | - Nathalie Majeau
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
| | - Charles Joly-Beauparlant
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Molecular Medicine, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Arnaud Droit
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Molecular Medicine, Université Laval, Quebec City, QC G1V 4G2, Canada
| | - Alain Bergeron
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Surgery, Université Laval, Quebec City, QC G1R 2J6, Canada
| | - Bernard Têtu
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Yves Fradet
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Surgery, Université Laval, Quebec City, QC G1R 2J6, Canada
| | - Frédéric Pouliot
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
- Department of Surgery, Université Laval, Quebec City, QC G1R 2J6, Canada
| | - Patrick Provost
- CHU de Québec Research Center/CHUL Pavilion—Université Laval, 2705 boulevard Laurier, Quebec City, QC G1V 4G2, Canada; (M.L.); (A.B.); (I.D.); (K.O.-B.); (N.M.); (C.J.-B.); (A.D.); (A.B.); (B.T.); (Y.F.); (F.P.)
- Department of Microbiology, Infectious Diseases and Immunology, Université Laval, Quebec City, QC G1V 4G2, Canada
- Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada
| |
Collapse
|
14
|
Takeda I, Araki M, Ishiguro KI, Ohga T, Takada K, Yamaguchi Y, Hashimoto K, Kai T, Nakagata N, Imasaka M, Yoshinobu K, Araki K. Gene trapping reveals a new transcriptionally active genome element: The chromosome-specific clustered trap region. Genes Cells 2021; 26:874-890. [PMID: 34418226 DOI: 10.1111/gtc.12890] [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: 02/19/2021] [Revised: 08/18/2021] [Accepted: 08/18/2021] [Indexed: 12/01/2022]
Abstract
Nearly half of the human genome consists of repetitive sequences such as long interspersed nuclear elements. The relationship between these repeating sequences and diseases has remained unclear. Gene trapping is a useful technique for disrupting a gene and expressing a reporter gene by using the promoter activity of the gene. The analysis of trapped genes revealed a new genome element-the chromosome-specific clustered trap (CSCT) region. For any examined sequence within this region, an equivalent was found using the BLAT of the University of California, Santa Cruz (UCSC) Genome Browser. CSCT13 mapped to chromosome 13 and contained only three genes. To elucidate its in vivo function, the whole CSCT13 region (1.6 Mbp) was deleted using the CRISPR/Cas9 system in mouse embryonic stem cells, and subsequently, a CSCT13 knockout mouse line was established. The rate of homozygotes was significantly lower than expected according to Mendel's laws. In addition, the number of offspring obtained by mating homozygotes was significantly smaller than that obtained by crossing controls. Furthermore, CSCT13 might have an effect on meiotic homologous recombination. This study identifies a transcriptionally active CSCT with an important role in mouse development.
Collapse
Affiliation(s)
- Iyo Takeda
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Masatake Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Kei-Ichiro Ishiguro
- Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Toshinori Ohga
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Kouki Takada
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Yusuke Yamaguchi
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Koichi Hashimoto
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Takuma Kai
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Naomi Nakagata
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Mai Imasaka
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Kumiko Yoshinobu
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| |
Collapse
|
15
|
Hori Y, Shimamoto A, Kobayashi T. The human ribosomal DNA array is composed of highly homogenized tandem clusters. Genome Res 2021; 31:1971-1982. [PMID: 34407983 PMCID: PMC8559705 DOI: 10.1101/gr.275838.121] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/09/2021] [Indexed: 11/25/2022]
Abstract
The structure of the human ribosomal DNA (rDNA) cluster has traditionally been hard to analyze owing to its highly repetitive nature. However, the recent development of long-read sequencing technology, such as Oxford Nanopore sequencing, has enabled us to study the large-scale structure of the genome. Using this technology, we found that human cells have a quite regular rDNA structure. Although each human rDNA copy has some variations in its noncoding region, contiguous copies of rDNA are similar, suggesting that homogenization through gene conversion frequently occurs between copies. Analysis of rDNA methylation by Nanopore sequencing further showed that all the noncoding regions are heavily methylated, whereas about half of the coding regions are clearly unmethylated. The ratio of unmethylated copies, which are speculated to be transcriptionally active, was lower in individuals with a higher rDNA copy number, suggesting that there is a mechanism that keeps the active copy number stable. In addition, the rDNA in progeroid syndrome patient cells with reduced DNA repair activity had more unstable copies compared with control normal cells, although the rate was much lower than previously reported using a fiber-FISH method. Collectively, our results clarify the view of rDNA stability and transcription regulation in human cells, indicating the presence of mechanisms for both homogenizations to ensure sequence quality and maintenance of active copies for cellular functions.
Collapse
Affiliation(s)
- Yutaro Hori
- Institute for Quantitative Biosciences, the University of Tokyo, Tokyo 133-0032, Japan
| | - Akira Shimamoto
- Faculty of Pharmaceutical Sciences, Sanyo-Onoda City University, Sanyo Onoda, Yamaguchi 756-0884, Japan
| | - Takehiko Kobayashi
- Institute for Quantitative Biosciences, the University of Tokyo, Tokyo 133-0032, Japan
| |
Collapse
|
16
|
Wen Y, Dungan CM, Mobley CB, Valentino T, von Walden F, Murach KA. Nucleus Type-Specific DNA Methylomics Reveals Epigenetic "Memory" of Prior Adaptation in Skeletal Muscle. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab038. [PMID: 34870208 PMCID: PMC8636928 DOI: 10.1093/function/zqab038] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023]
Abstract
Using a mouse model of conditional and inducible in vivo fluorescent myonuclear labeling (HSA-GFP), sorting purification of nuclei, low-input reduced representation bisulfite sequencing (RRBS), and a translatable and reversible model of exercise (progressive weighted wheel running, PoWeR), we provide the first nucleus type-specific epigenetic information on skeletal muscle adaptation and detraining. Adult (>4 mo) HSA-GFP mice performed PoWeR for 8 wk then detrained for 12 wk; age-matched untrained mice were used to control for the long duration of the study. Myonuclei and interstitial nuclei from plantaris muscles were isolated for RRBS. Relative to untrained, PoWeR caused similar myonuclear CpG hypo- and hyper-methylation of promoter regions and substantial hypomethylation in interstitial nuclear promoters. Over-representation analysis of promoters revealed a larger number of hyper- versus hypo-methylated pathways in both nuclear populations after training and evidence for reciprocal regulation of methylation between nucleus types, with hypomethylation of promoter regions in Wnt signaling-related genes in myonuclei and hypermethylation in interstitial nuclei. After 12 wk of detraining, promoter CpGs in documented muscle remodeling-associated genes and pathways that were differentially methylated immediately after PoWeR were persistently differentially methylated in myonuclei, along with long-term promoter hypomethylation in interstitial nuclei. No enduring gene expression changes in muscle tissue were observed using RNA-sequencing. Upon 4 wk of retraining, mice that trained previously grew more at the whole muscle and fiber type-specific cellular level than training naïve mice, with no difference in myonuclear number. Muscle nuclei have a methylation epi-memory of prior training that may augment muscle adaptability to retraining.
Collapse
Affiliation(s)
- Yuan Wen
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA,College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - C Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Taylor Valentino
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm 171 77, Sweden
| | | |
Collapse
|
17
|
Figueiredo VC, Wen Y, Alkner B, Fernandez-Gonzalo R, Norrbom J, Vechetti IJ, Valentino T, Mobley CB, Zentner GE, Peterson CA, McCarthy JJ, Murach KA, von Walden F. Genetic and epigenetic regulation of skeletal muscle ribosome biogenesis with exercise. J Physiol 2021; 599:3363-3384. [PMID: 33913170 DOI: 10.1113/jp281244] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/20/2021] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Ribosome biogenesis and MYC transcription are associated with acute resistance exercise (RE) and are distinct from endurance exercise in human skeletal muscle throughout a 24 h time course of recovery. A PCR-based method for relative ribosomal DNA (rDNA) copy number estimation was validated by whole genome sequencing and revealed that rDNA dosage is positively correlated with ribosome biogenesis in response to RE. Acute RE modifies rDNA methylation patterns in enhancer, intergenic spacer and non-canonical MYC-associated regions, but not the promoter. Myonuclear-specific rDNA methylation patterns with acute mechanical overload in mice corroborate and expand on rDNA findings with RE in humans. A genetic predisposition for hypertrophic responsiveness may exist based on rDNA gene dosage. ABSTRACT Ribosomes are the macromolecular engines of protein synthesis. Skeletal muscle ribosome biogenesis is stimulated by exercise, although the contribution of ribosomal DNA (rDNA) copy number and methylation to exercise-induced rDNA transcription is unclear. To investigate the genetic and epigenetic regulation of ribosome biogenesis with exercise, a time course of skeletal muscle biopsies was obtained from 30 participants (18 men and 12 women; 31 ± 8 years, 25 ± 4 kg m-2 ) at rest and 30 min, 3 h, 8 h and 24 h after acute endurance (n = 10, 45 min cycling, 70% V ̇ O 2 max ) or resistance exercise (n = 10, 4 × 7 × 2 exercises); 10 control participants underwent biopsies without exercise. rDNA transcription and dosage were assessed using quantitative PCR and whole genome sequencing. rDNA promoter methylation was investigated using massARRAY EpiTYPER and global rDNA CpG methylation was assessed using reduced-representation bisulphite sequencing. Ribosome biogenesis and MYC transcription were associated primarily with resistance but not endurance exercise, indicating preferential up-regulation during hypertrophic processes. With resistance exercise, ribosome biogenesis was associated with rDNA gene dosage, as well as epigenetic changes in enhancer and non-canonical MYC-associated areas in rDNA, but not the promoter. A mouse model of in vivo metabolic RNA labelling and genetic myonuclear fluorescence labelling validated the effects of an acute hypertrophic stimulus on ribosome biogenesis and Myc transcription, and also corroborated rDNA enhancer and Myc-associated methylation alterations specifically in myonuclei. The present study provides the first information on skeletal muscle genetic and rDNA gene-wide epigenetic regulation of ribosome biogenesis in response to exercise, revealing novel roles for rDNA dosage and CpG methylation.
Collapse
Affiliation(s)
- Vandré C Figueiredo
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Yuan Wen
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Björn Alkner
- Department of Orthopaedics, Eksjö, Region Jönköping County and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Rodrigo Fernandez-Gonzalo
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Jessica Norrbom
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ivan J Vechetti
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, NE, USA
| | - Taylor Valentino
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - C Brooks Mobley
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | | | - Charlotte A Peterson
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Kevin A Murach
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Ferdinand von Walden
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.,Department of Physiology, University of Kentucky, Lexington, KY, USA.,Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
18
|
Kveštak D, Juranić Lisnić V, Lisnić B, Tomac J, Golemac M, Brizić I, Indenbirken D, Cokarić Brdovčak M, Bernardini G, Krstanović F, Rožmanić C, Grundhoff A, Krmpotić A, Britt WJ, Jonjić S. NK/ILC1 cells mediate neuroinflammation and brain pathology following congenital CMV infection. J Exp Med 2021; 218:e20201503. [PMID: 33630019 PMCID: PMC7918636 DOI: 10.1084/jem.20201503] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/11/2020] [Accepted: 01/29/2021] [Indexed: 12/31/2022] Open
Abstract
Congenital human cytomegalovirus (cHCMV) infection of the brain is associated with a wide range of neurocognitive sequelae. Using infection of newborn mice with mouse cytomegalovirus (MCMV) as a reliable model that recapitulates many aspects of cHCMV infection, including disseminated infection, CNS infection, altered neurodevelopment, and sensorineural hearing loss, we have previously shown that mitigation of inflammation prevented alterations in cerebellar development, suggesting that host inflammatory factors are key drivers of neurodevelopmental defects. Here, we show that MCMV infection causes a dramatic increase in the expression of the microglia-derived chemokines CXCL9/CXCL10, which recruit NK and ILC1 cells into the brain in a CXCR3-dependent manner. Surprisingly, brain-infiltrating innate immune cells not only were unable to control virus infection in the brain but also orchestrated pathological inflammatory responses, which lead to delays in cerebellar morphogenesis. Our results identify NK and ILC1 cells as the major mediators of immunopathology in response to virus infection in the developing CNS, which can be prevented by anti-IFN-γ antibodies.
Collapse
MESH Headings
- Animals
- Animals, Newborn
- Brain/immunology
- Brain/pathology
- Brain/virology
- Chemokine CXCL10/genetics
- Chemokine CXCL10/immunology
- Chemokine CXCL10/metabolism
- Chemokine CXCL9/genetics
- Chemokine CXCL9/immunology
- Chemokine CXCL9/metabolism
- Cytomegalovirus/immunology
- Cytomegalovirus/physiology
- Cytomegalovirus Infections/immunology
- Cytomegalovirus Infections/virology
- Gene Expression Regulation/immunology
- Humans
- Immunity, Innate/immunology
- Inflammation/genetics
- Inflammation/immunology
- Inflammation/virology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lymphocytes/immunology
- Lymphocytes/metabolism
- Mice, 129 Strain
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Microglia/immunology
- Microglia/metabolism
- Microglia/virology
- Receptors, CXCR3/genetics
- Receptors, CXCR3/immunology
- Receptors, CXCR3/metabolism
- Mice
Collapse
Affiliation(s)
- Daria Kveštak
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Vanda Juranić Lisnić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Berislav Lisnić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jelena Tomac
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Mijo Golemac
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Ilija Brizić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Daniela Indenbirken
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | | | - Giovanni Bernardini
- Department of Molecular Medicine, Faculty of Pharmacy and Medicine, University of Rome “Sapienza”, Rome, Italy
| | - Fran Krstanović
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Carmen Rožmanić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Adam Grundhoff
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Astrid Krmpotić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - William J. Britt
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
| | - Stipan Jonjić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| |
Collapse
|
19
|
Poot M, Hochstenbach R. Prevalence and Phenotypic Impact of Robertsonian Translocations. Mol Syndromol 2021; 12:1-11. [PMID: 33776621 PMCID: PMC7983559 DOI: 10.1159/000512676] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Robertsonian translocations (RTs) result from fusion of 2 acrocentric chromosomes (e.g., 13, 14, 15, 21, 22) and consequential losses of segments of the p arms containing 47S rDNA clusters and transcription factor binding sites. Depending on the position of the breakpoints, the size of these losses vary considerably between types of RTs. The prevalence of RTs in the general population is estimated to be around 1 per 800 individuals, making RTs the most common chromosomal rearrangement in healthy individuals. Based on their prevalence, RTs are classified as "common," rob(13;14) and rob(14;21), or "rare" (the 8 remaining nonhomologous combinations). Carriers of RTs are at an increased risk for offspring with chromosomal imbalances or with uniparental disomy. RTs are generally regarded as phenotypically neutral, although, due to RTs formation, 2 of the 10 ribosomal rDNA gene clusters, several long noncoding RNAs, and in the case of RTs involving chromosome 21, several mRNA encoding genes are lost. Nevertheless, recent evidence indicates that RTs may have a significant phenotypic impact. In particular, rob(13;14) carriers have a significantly elevated risk for breast cancer. While RTs are easily spotted by routine karyotyping, they may go unnoticed if only array-CGH and NextGen sequencing methods are applied. This review first discusses possible molecular mechanisms underlying the particularly high rates of RT formation and their incidence in the general population, and second, likely causes for the elevated cancer risk of some RTs will be examined.
Collapse
Affiliation(s)
- Martin Poot
- Department of Human Genetics, University of Würzburg, Würzburg, Germany
| | - Ron Hochstenbach
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
20
|
Age-Dependent Ribosomal DNA Variations in Mice. Mol Cell Biol 2020; 40:MCB.00368-20. [PMID: 32900821 PMCID: PMC7588874 DOI: 10.1128/mcb.00368-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/02/2020] [Indexed: 12/22/2022] Open
Abstract
The rRNA gene, which consists of tandem repetitive arrays (ribosomal DNA [rDNA] repeat), is one of the most unstable regions in the genome. The rDNA repeat in the budding yeast Saccharomyces cerevisiae is known to become unstable as the cell ages. However, it is unclear how the rDNA repeat changes in aging mammalian cells. Using quantitative single-cell analyses, we identified age-dependent alterations in rDNA copy number and levels of methylation in mice. The degree of methylation and copy number of rDNA from bone marrow cells of 2-year-old mice were increased by comparison to levels in 4-week-old mice in two mouse strains, BALB/cA and C57BL/6. The rRNA gene, which consists of tandem repetitive arrays (ribosomal DNA [rDNA] repeat), is one of the most unstable regions in the genome. The rDNA repeat in the budding yeast Saccharomyces cerevisiae is known to become unstable as the cell ages. However, it is unclear how the rDNA repeat changes in aging mammalian cells. Using quantitative single-cell analyses, we identified age-dependent alterations in rDNA copy number and levels of methylation in mice. The degree of methylation and copy number of rDNA from bone marrow cells of 2-year-old mice were increased by comparison to levels in 4-week-old mice in two mouse strains, BALB/cA and C57BL/6. Moreover, the level of pre-rRNA transcripts was reduced in older BALB/cA mice. We also identified many sequence variations in the rDNA. Among them, three mutations were unique to old mice, and two of them were found in the conserved region in budding yeast. We established yeast strains with the old-mouse-specific mutations and found that they shortened the life span of the cells. Our findings suggest that rDNA is also fragile in mammalian cells and that alterations within this region have a profound effect on cellular function.
Collapse
|
21
|
Maiser A, Dillinger S, Längst G, Schermelleh L, Leonhardt H, Németh A. Super-resolution in situ analysis of active ribosomal DNA chromatin organization in the nucleolus. Sci Rep 2020; 10:7462. [PMID: 32366902 PMCID: PMC7198602 DOI: 10.1038/s41598-020-64589-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 04/01/2020] [Indexed: 12/21/2022] Open
Abstract
Ribosomal RNA (rRNA) transcription by RNA polymerase I (Pol I) is the first key step of ribosome biogenesis. While the molecular mechanisms of rRNA transcription regulation have been elucidated in great detail, the functional organization of the multicopy rRNA gene clusters (rDNA) in the nucleolus is less well understood. Here we apply super-resolution 3D structured illumination microscopy (3D-SIM) to investigate the spatial organization of transcriptionally competent active rDNA chromatin at size scales well below the diffraction limit by optical microscopy. We identify active rDNA chromatin units exhibiting uniformly ring-shaped conformations with diameters of ~240 nm in mouse and ~170 nm in human fibroblasts, consistent with rDNA looping. The active rDNA chromatin units are clearly separated from each other and from the surrounding areas of rRNA processing. Simultaneous imaging of all active genes bound by Pol I and the architectural chromatin protein Upstream Binding Transcription Factor (UBF) reveals a random spatial orientation of regular repeats of rDNA coding sequences within the nucleoli. These observations imply rDNA looping and exclude potential formation of systematic spatial assemblies of the well-ordered repetitive arrays of transcription units. Collectively, this study uncovers key features of the 3D organization of active rDNA chromatin units and their nucleolar clusters providing a spatial framework of nucleolar chromatin organization at unprecedented detail.
Collapse
Affiliation(s)
- Andreas Maiser
- Department of Biology II, Ludwig-Maximilians-Universität München, München, Germany
| | - Stefan Dillinger
- Department of Biochemistry III, University of Regensburg, Regensburg, Germany
| | - Gernot Längst
- Department of Biochemistry III, University of Regensburg, Regensburg, Germany
| | - Lothar Schermelleh
- Micron Advanced Bioimaging Unit, Department of Biochemistry, University of Oxford, Oxford, UK
| | - Heinrich Leonhardt
- Department of Biology II, Ludwig-Maximilians-Universität München, München, Germany
| | - Attila Németh
- Department of Biochemistry III, University of Regensburg, Regensburg, Germany.
- Institute of Neuropathology, Justus Liebig University, Giessen, Germany.
| |
Collapse
|
22
|
Tuck AC, Rankova A, Arpat AB, Liechti LA, Hess D, Iesmantavicius V, Castelo-Szekely V, Gatfield D, Bühler M. Mammalian RNA Decay Pathways Are Highly Specialized and Widely Linked to Translation. Mol Cell 2020; 77:1222-1236.e13. [PMID: 32048998 PMCID: PMC7083229 DOI: 10.1016/j.molcel.2020.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/11/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
RNA decay is crucial for mRNA turnover and surveillance and misregulated in many diseases. This complex system is challenging to study, particularly in mammals, where it remains unclear whether decay pathways perform specialized versus redundant roles. Cytoplasmic pathways and links to translation are particularly enigmatic. By directly profiling decay factor targets and normal versus aberrant translation in mouse embryonic stem cells (mESCs), we uncovered extensive decay pathway specialization and crosstalk with translation. XRN1 (5'-3') mediates cytoplasmic bulk mRNA turnover whereas SKIV2L (3'-5') is universally recruited by ribosomes, tackling aberrant translation and sometimes modulating mRNA abundance. Further exploring translation surveillance revealed AVEN and FOCAD as SKIV2L interactors. AVEN prevents ribosome stalls at structured regions, which otherwise require SKIV2L for clearance. This pathway is crucial for histone translation, upstream open reading frame (uORF) regulation, and counteracting ribosome arrest on small ORFs. In summary, we uncovered key targets, components, and functions of mammalian RNA decay pathways and extensive coupling to translation.
Collapse
Affiliation(s)
- Alex Charles Tuck
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Aneliya Rankova
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Alaaddin Bulak Arpat
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Luz Angelica Liechti
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Vytautas Iesmantavicius
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | | | - David Gatfield
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Petersplatz 10, 4003 Basel, Switzerland.
| |
Collapse
|
23
|
Mahadevan IA, Kumar S, Rao MRS. Linker histone variant H1t is closely associated with repressed repeat-element chromatin domains in pachytene spermatocytes. Epigenetics Chromatin 2020; 13:9. [PMID: 32131873 PMCID: PMC7057672 DOI: 10.1186/s13072-020-00335-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/20/2020] [Indexed: 12/22/2022] Open
Abstract
Background H1t is the major linker histone variant in pachytene spermatocytes, where it constitutes 50–60% of total H1. This linker histone variant was previously reported to localize in the nucleolar rDNA element in mouse spermatocytes. Our main aim was to determine the extra-nucleolar localization of this linker histone variant in pachytene spermatocytes. Results We generated H1t-specific antibodies in rabbits and validated its specificity by multiple assays like ELISA, western blot, etc. Genome-wide occupancy studies, as determined by ChIP-sequencing in P20 mouse testicular cells revealed that H1t did not closely associate with active gene promoters and open chromatin regions. Annotation of H1t-bound genomic regions revealed that H1t is depleted from DSB hotspots and TSS, but are predominantly associated with retrotransposable repeat elements like LINE and LTR in pachytene spermatocytes. These chromatin domains are repressed based on co-association of H1t observed with methylated CpGs and repressive histone marks like H3K9me3 and H4K20me3 in vivo. Mass spectrometric analysis of proteins associated with H1t-containing oligonucleosomes identified piRNA–PIWI pathway proteins, repeat repression-associated proteins and heterochromatin proteins confirming the association with repressed repeat-element genomic regions. We validated the interaction of key proteins with H1t-containing oligonucleosomes by use of ChIP-western blot assays. On the other hand, we observe majority of H1t peaks to be associated with the intergenic spacer of the rDNA element, also in association with SINE elements of the rDNA element. Thus, we have identified the genomic and chromatin features of both nucleolar and extranucleolar localization patterns of linker histone H1t in the context of pachytene spermatocytes. Conclusions H1t-containing repeat-element LINE and LTR chromatin domains are associated with repressive marks like methylated CpGs, histone modifications H3K9me3 and H4K20me3, and heterochromatin proteins like HP1β, Trim28, PIWIL1, etc. Apart from localization of H1t at the rDNA element, we demonstrate the extranucleolar association of this linker histone variant at repeat-associated chromatin domains in pachytene spermatocytes. We hypothesize that H1t might induce local chromatin relaxation to recruit heterochromatin and repeat repression-associated protein factors necessary for TE (transposable element) repression, the final biological effect being formation of closed chromatin repressed structures.
Collapse
Affiliation(s)
- Iyer Aditya Mahadevan
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Sanjeev Kumar
- BioCOS Life Sciences Private Limited, SAAMI Building, 851/A, AECS Layout, B-Block, Singasandra Hosur Road, Bangalore, India
| | | |
Collapse
|
24
|
Dyomin A, Galkina S, Fillon V, Cauet S, Lopez-Roques C, Rodde N, Klopp C, Vignal A, Sokolovskaya A, Saifitdinova A, Gaginskaya E. Structure of the intergenic spacers in chicken ribosomal DNA. Genet Sel Evol 2019; 51:59. [PMID: 31655542 PMCID: PMC6815422 DOI: 10.1186/s12711-019-0501-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 10/14/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ribosomal DNA (rDNA) repeats are situated in the nucleolus organizer regions (NOR) of chromosomes and transcribed into rRNA for ribosome biogenesis. Thus, they are an essential component of eukaryotic genomes. rDNA repeat units consist of rRNA gene clusters that are transcribed into single pre-rRNA molecules, each separated by intergenic spacers (IGS) that contain regulatory elements for rRNA gene cluster transcription. Because of their high repeat content, rDNA sequences are usually absent from genome assemblies. In this work, we used the long-read sequencing technology to describe the chicken IGS and fill the knowledge gap on rDNA sequences of one of the key domesticated animals. METHODS We used the long-read PacBio RSII technique to sequence the BAC clone WAG137G04 (Wageningen BAC library) known to contain chicken NOR elements and the HGAP workflow software suit to assemble the PacBio RSII reads. Whole-genome sequence contigs homologous to the chicken rDNA repetitive unit were identified based on the Gallus_gallus-5.0 assembly with BLAST. We used the Geneious 9.0.5 and Mega software, maximum likelihood method and Chickspress project for sequence evolution analysis, phylogenetic tree construction and analysis of the raw transcriptome data. RESULTS Three complete IGS sequences in the White Leghorn chicken genome and one IGS sequence in the red junglefowl contig AADN04001305.1 (Gallus_gallus-5.0) were detected. They had various lengths and contained three groups of tandem repeats (some of them being very GC rich) that form highly organized arrays. Initiation and termination sites of rDNA transcription were located within small and large unique regions (SUR and LUR), respectively. No functionally significant sites were detected within the tandem repeat sequences. CONCLUSIONS Due to the highly organized GC-rich repeats, the structure of the chicken IGS differs from that of IGS in human, apes, Xenopus or fish rDNA. However, the chicken IGS shares some molecular organization features with that of the turtles, which are other representatives of the Sauropsida clade that includes birds and reptiles. Our current results on the structure of chicken IGS together with the previously reported ribosomal gene cluster sequence provide sufficient data to consider that the complete chicken rDNA sequence is assembled with confidence in terms of molecular DNA organization.
Collapse
Affiliation(s)
- Alexander Dyomin
- Saint Petersburg State University, Universitetskaya emb. 7/9, Saint Petersburg, 199034, Russian Federation.,Saratov State Medical University, Bolshaya Kazachia Str. 112, Saratov, Russian Federation
| | - Svetlana Galkina
- Saint Petersburg State University, Universitetskaya emb. 7/9, Saint Petersburg, 199034, Russian Federation
| | - Valerie Fillon
- INRA, GenPhySE, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Stephane Cauet
- INRA, CNRGV, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Celine Lopez-Roques
- INRA, GeT-PlaGe, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Nathalie Rodde
- INRA, CNRGV, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Christophe Klopp
- INRA, Sigenae, MIAT, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Alain Vignal
- INRA, GenPhySE, 24 Chemin de Borde Rouge, Auzeville, 31326, Castanet Tolosan, France
| | - Anastasia Sokolovskaya
- Saint Petersburg State University, Universitetskaya emb. 7/9, Saint Petersburg, 199034, Russian Federation
| | - Alsu Saifitdinova
- Herzen State Pedagogical University of Russia, Moika Emb. 48, Saint Petersburg, 191186, Russian Federation
| | - Elena Gaginskaya
- Saint Petersburg State University, Universitetskaya emb. 7/9, Saint Petersburg, 199034, Russian Federation.
| |
Collapse
|
25
|
Guo Z, Han L, Liang Z, Hou X. Comparative analysis of the ribosomal DNA repeat unit (rDNA) of Perna viridis (Linnaeus, 1758) and Perna canaliculus (Gmelin, 1791). PeerJ 2019; 7:e7644. [PMID: 31534863 PMCID: PMC6730533 DOI: 10.7717/peerj.7644] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 08/08/2019] [Indexed: 11/22/2022] Open
Abstract
Perna viridis and P. canaliculus are economically and ecologically important species of shellfish. In this study, the complete ribosomal DNA (rDNA) unit sequences of these species were determined for the first time. The gene order, 18S rRNA-internal transcribed spacer (ITS) 1-5.8S rRNA-ITS2-28S rRNA-intergenic spacer (IGS), was similar to that observed in other eukaryotes. The lengths of the P. viridis and P. canaliculus rDNA sequences ranged from 8,432 to 8,616 bp and from 7,597 to 7,610 bp, respectively, this variability was mainly attributable to the IGS region. The putative transcription termination site and initiation site were confirmed. Perna viridis and P. canaliculus rDNA contained two (length: 93 and 40 bp) and one (length: 131 bp) repeat motifs, respectively. Individual intra-species differences mainly involved the copy number of repeat units. In P. viridis, three cytosine-guanine (CpG) sites with sizes of 440, 1,075 and 537 bp were found to cover nearly the entire IGS sequence, whereas in P. canaliculus, two CpG islands with sizes of 361 and 484 bp were identified. The phylogenetic trees constructed with maximum likelihood and neighbour-joining methods and based on ITS sequences were identical and included three major clusters. Species of the same genus were easily clustered together.
Collapse
Affiliation(s)
| | - Leng Han
- Shandong University at Weihai, Weihai, China
| | | | - Xuguang Hou
- Shandong University at Weihai, Weihai, China
| |
Collapse
|
26
|
Khalid M, Abdollahi M. Epigenetic modifications associated with pathophysiological effects of lead exposure. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2019; 37:235-287. [PMID: 31402779 DOI: 10.1080/10590501.2019.1640581] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lead (Pb) exposure during different stages of development has demonstrated dose, duration, sex, and tissue-specific pathophysiological outcomes due to altered epigenetic regulation via (a) DNA methylation, (b) histone modifications, (c) miRNAs, and (d) chromatin accessibility. Pb-induced alteration of epigenetic regulation causes neurotoxic and extra-neurotoxic pathophysiological outcomes. Neurotoxic effects of Pb include dysfunction of memory and learning, behavioral disorder, attention deficit hyperactivity disorder, autism spectrum disorder, aging, Alzheimer's disease, tauopathy, and neurodegeneration. Extra-neurotoxic effects of Pb include altered body weight, metabolic disorder, cardiovascular disorders, hematopoietic disorder, and reproductive impairment. Pb exposure either early in life or at any stage of development results in undesirable pathophysiological outcomes that tends to sustain and maintain for a lifetime.
Collapse
Affiliation(s)
- Madiha Khalid
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), Tehran, Iran
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
27
|
von Walden F. Ribosome biogenesis in skeletal muscle: coordination of transcription and translation. J Appl Physiol (1985) 2019; 127:591-598. [PMID: 31219775 DOI: 10.1152/japplphysiol.00963.2018] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle mass responds in a remarkable manner to alterations in loading and use. It has long been clear that skeletal muscle hypertrophy can be prevented by inhibiting RNA synthesis. Since 80% of the cell's total RNA has been estimated to be rRNA, this finding indicates that de novo production of rRNA via transcription of the corresponding genes is important for such hypertrophy to occur. Transcription of rDNA by RNA Pol I is the rate-limiting step in ribosome biogenesis, indicating in turn that this biogenesis strongly influences the hypertrophic response. The present minireview focuses on 1) a brief description of the key steps in ribosome biogenesis and the relationship of this process to skeletal muscle mass and 2) the coordination of ribosome biogenesis and protein synthesis for growth or atrophy, as exemplified by the intracellular AMPK and mTOR pathways.
Collapse
Affiliation(s)
- Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
| |
Collapse
|
28
|
Potapova TA, Gerton JL. Ribosomal DNA and the nucleolus in the context of genome organization. Chromosome Res 2019; 27:109-127. [PMID: 30656516 DOI: 10.1007/s10577-018-9600-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/13/2018] [Accepted: 12/17/2018] [Indexed: 12/12/2022]
Abstract
The nucleolus constitutes a prominent nuclear compartment, a membraneless organelle that was first documented in the 1830s. The fact that specific chromosomal regions were present in the nucleolus was recognized by Barbara McClintock in the 1930s, and these regions were termed nucleolar organizing regions, or NORs. The primary function of ribosomal DNA (rDNA) is to produce RNA components of ribosomes. Yet, ribosomal DNA also plays a pivotal role in nuclear organization by assembling the nucleolus. This review is focused on the rDNA and associated proteins in the context of genome organization. Recent advances in understanding chromatin organization suggest that chromosomes are organized into topological domains by a DNA loop extrusion process. We discuss the perspective that rDNA may also be organized in topological domains constrained by structural maintenance of chromosome protein complexes such as cohesin and condensin. Moreover, biophysical studies indicate that the nucleolar compartment may be formed by active processes as well as phase separation, a perspective that lends further insight into nucleolar organization. The application of the latest perspectives and technologies to this organelle help further elucidate its role in nuclear structure and function.
Collapse
Affiliation(s)
| | - Jennifer L Gerton
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, USA
| |
Collapse
|
29
|
Kinase-dead ATR differs from ATR loss by limiting the dynamic exchange of ATR and RPA. Nat Commun 2018; 9:5351. [PMID: 30559436 PMCID: PMC6297235 DOI: 10.1038/s41467-018-07798-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 11/27/2018] [Indexed: 12/21/2022] Open
Abstract
ATR kinase is activated by RPA-coated single-stranded DNA (ssDNA) to orchestrate DNA damage responses. Here we show that ATR inhibition differs from ATR loss. Mouse model expressing kinase-dead ATR (Atr+/KD), but not loss of ATR (Atr+/−), displays ssDNA-dependent defects at the non-homologous region of X-Y chromosomes during male meiosis leading to sterility, and at telomeres, rDNA, and fragile sites during mitosis leading to lymphocytopenia. Mechanistically, we find that ATR kinase activity is necessary for the rapid exchange of ATR at DNA-damage-sites, which in turn promotes CHK1-phosphorylation. ATR-KD, but not loss of ATR, traps a subset of ATR and RPA on chromatin, where RPA is hyper-phosphorylated by ATM/DNA-PKcs and prevents downstream repair. Consequently, Atr+/KD cells have shorter inter-origin distances and are vulnerable to induced fork collapses, genome instability and mitotic catastrophe. These results reveal mechanistic differences between ATR inhibition and ATR loss, with implications for ATR signaling and cancer therapy. ATR kinase is a key regulator of chromosome integrity. Here the authors by analysing the phenotype of a mouse model expressing a kinase-dead ATR, reveal the effect of ATR inhibition compared to ATR loss and its consequences for meiosis, DNA replication, checkpoint activation and genome instability .
Collapse
|
30
|
Tuck AC, Natarajan KN, Rice GM, Borawski J, Mohn F, Rankova A, Flemr M, Wenger A, Nutiu R, Teichmann S, Bühler M. Distinctive features of lincRNA gene expression suggest widespread RNA-independent functions. Life Sci Alliance 2018; 1:e201800124. [PMID: 30456373 PMCID: PMC6238598 DOI: 10.26508/lsa.201800124] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 07/13/2018] [Accepted: 07/13/2018] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic genomes produce RNAs lacking protein-coding potential, with enigmatic roles. We integrated three approaches to study large intervening noncoding RNA (lincRNA) gene functions. First, we profiled mouse embryonic stem cells and neural precursor cells at single-cell resolution, revealing lincRNAs expressed in specific cell types, cell subpopulations, or cell cycle stages. Second, we assembled a transcriptome-wide atlas of nuclear lincRNA degradation by identifying targets of the exosome cofactor Mtr4. Third, we developed a reversible depletion system to separate the role of a lincRNA gene from that of its RNA. Our approach distinguished lincRNA loci functioning in trans from those modulating local gene expression. Some genes express stable and/or abundant lincRNAs in single cells, but many prematurely terminate transcription and produce lincRNAs rapidly degraded by the nuclear exosome. This suggests that besides RNA-dependent functions, lincRNA loci act as DNA elements or through transcription. Our integrative approach helps distinguish these mechanisms.
Collapse
Affiliation(s)
- Alex C Tuck
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Kedar Nath Natarajan
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Danish Institute of Advanced Study and Functional Genomics and Metabolism Unit, University of Southern Denmark, Denmark
| | - Greggory M Rice
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Jason Borawski
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Fabio Mohn
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Aneliya Rankova
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Matyas Flemr
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Alice Wenger
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Razvan Nutiu
- Novartis Institutes for Biomedical Research, Cambridge, MA, USA
| | - Sarah Teichmann
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.,Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| |
Collapse
|
31
|
The Case of X and Y Localization of Nucleolus Organizer Regions (NORs) in Tragulus javanicus (Cetartiodactyla, Mammalia). Genes (Basel) 2018; 9:genes9060312. [PMID: 29925822 PMCID: PMC6027365 DOI: 10.3390/genes9060312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/14/2018] [Accepted: 06/18/2018] [Indexed: 11/17/2022] Open
Abstract
There are differences in number and localization of nucleolus organizer regions (NORs) in genomes. In mammalian genomes, NORs are located on autosomes, which are often situated on short arms of acrocentric chromosomes and more rarely in telomeric, pericentromeric, or interstitial regions. In this work, we report the unique case of active NORs located on gonоsomes of a eutherian mammal, the Javan mouse-deer (Tragulus javanicus). We have investigated the position of NORs by FISH experiments with ribosomal DNA (rDNA) sequences (18S, 5.8S, and 28S) and show the presence of a single NOR site on the X and Y chromosomes. The NOR is localized interstitially on the p-arm of the X chromosome in close proximity with prominent C-positive heterochromatin blocks and in the pericentromeric area of mostly heterochromatic Y. The NOR sites are active on both the X and Y chromosomes in the studied individual and surrounded by GC enriched heterochromatin. We hypothesize that the surrounding heterochromatin might have played a role in the transfer of NORs from autosomes to sex chromosomes during the karyotype evolution of the Javan mouse-deer.
Collapse
|
32
|
Abstract
Ribosome biogenesis is a complex and highly energy-demanding process that requires the concerted action of all three nuclear RNA polymerases (Pol I-III) in eukaryotes. The three largest ribosomal RNAs (rRNAs) originate from a precursor transcript (pre-rRNA) that is encoded by multicopy genes located in the nucleolus. Transcription of these rRNA genes (rDNA) by Pol I is the key regulation step in ribosome production and is tightly controlled by an intricate network of signaling pathways and epigenetic mechanisms. In this article, we give an overview of the composition of the basal Pol I machinery and rDNA chromatin. We discuss rRNA gene regulation in response to environmental signals and developmental cues and focus on perturbations occurring in diseases linked to either excessive or limited rRNA levels. Finally, we discuss the emerging view that rDNA integrity and activity may be involved in the aging process.
Collapse
Affiliation(s)
- Samim Sharifi
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University, 07745 Jena, Germany; , .,Leibniz-Institute on Aging-Fritz Lipmann Institute, 07745 Jena, Germany
| | - Holger Bierhoff
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University, 07745 Jena, Germany; , .,Leibniz-Institute on Aging-Fritz Lipmann Institute, 07745 Jena, Germany
| |
Collapse
|
33
|
Maldonado R, Filarsky M, Grummt I, Längst G. Purine- and pyrimidine-triple-helix-forming oligonucleotides recognize qualitatively different target sites at the ribosomal DNA locus. RNA (NEW YORK, N.Y.) 2018; 24:371-380. [PMID: 29222118 PMCID: PMC5824356 DOI: 10.1261/rna.063800.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/30/2017] [Indexed: 05/04/2023]
Abstract
Triplexes are noncanonical DNA structures, which are functionally associated with regulation of gene expression through ncRNA targeting to chromatin. Based on the rules of Hoogsteen base-pairing, polypurine sequences of a duplex can potentially form triplex structures with single-stranded oligonucleotides. Prediction of triplex-forming sequences by bioinformatics analyses have revealed enrichment of potential triplex targeting sites (TTS) at regulatory elements, mainly in promoters and enhancers, suggesting a potential function of RNA-DNA triplexes in transcriptional regulation. Here, we have quantitatively evaluated the potential of different sequences of human and mouse ribosomal RNA genes (rDNA) to form triplexes at different salt and pH conditions. We show by biochemical and biophysical approaches that some of these predicted sequences form triplexes with high affinity, following the canonical rules for triplex formation. We further show that RNA triplex-forming oligos (TFOs) are more stable than their DNA counterpart, and point mutations strongly affect triplex formation. We further show differential sequence requirements of pyrimidine and purine TFO sequences for efficient binding, depending on the G-C content of the TTS. The unexpected sequence specificity, revealing distinct sequence requirements for purine and pyrimidine TFOs, shows that in addition to the Hoogsteen pairing rules, a sequence code and mutations have to be taken into account to predict genomic TTS.
Collapse
Affiliation(s)
- Rodrigo Maldonado
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
| | - Michael Filarsky
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
| | - Ingrid Grummt
- Division of Molecular Biology of the Cell II, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Gernot Längst
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
| |
Collapse
|
34
|
Parks MM, Kurylo CM, Dass RA, Bojmar L, Lyden D, Vincent CT, Blanchard SC. Variant ribosomal RNA alleles are conserved and exhibit tissue-specific expression. SCIENCE ADVANCES 2018; 4:eaao0665. [PMID: 29503865 PMCID: PMC5829973 DOI: 10.1126/sciadv.aao0665] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 01/08/2018] [Indexed: 05/25/2023]
Abstract
The ribosome, the integration point for protein synthesis in the cell, is conventionally considered a homogeneous molecular assembly that only passively contributes to gene expression. Yet, epigenetic features of the ribosomal DNA (rDNA) operon and changes in the ribosome's molecular composition have been associated with disease phenotypes, suggesting that the ribosome itself may possess inherent regulatory capacity. Analyzing whole-genome sequencing data from the 1000 Genomes Project and the Mouse Genomes Project, we find that rDNA copy number varies widely across individuals, and we identify pervasive intra- and interindividual nucleotide variation in the 5S, 5.8S, 18S, and 28S ribosomal RNA (rRNA) genes of both human and mouse. Conserved rRNA sequence heterogeneities map to functional centers of the assembled ribosome, variant rRNA alleles exhibit tissue-specific expression, and ribosomes bearing variant rRNA alleles are present in the actively translating ribosome pool. These findings provide a critical framework for exploring the possibility that the expression of genomically encoded variant rRNA alleles gives rise to physically and functionally heterogeneous ribosomes that contribute to mammalian physiology and human disease.
Collapse
Affiliation(s)
- Matthew M. Parks
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Chad M. Kurylo
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Randall A. Dass
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
| | - Linda Bojmar
- Children’s Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children’s Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Surgery, County Council of Östergötland, and Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, 58185 Linköping, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - David Lyden
- Children’s Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children’s Health, Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - C. Theresa Vincent
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Scott C. Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY 10065, USA
- Tri-Institutional Training Program in Chemical Biology, Weill Cornell Medicine, New York, NY 10065, USA
| |
Collapse
|
35
|
Herdman C, Mars JC, Stefanovsky VY, Tremblay MG, Sabourin-Felix M, Lindsay H, Robinson MD, Moss T. A unique enhancer boundary complex on the mouse ribosomal RNA genes persists after loss of Rrn3 or UBF and the inactivation of RNA polymerase I transcription. PLoS Genet 2017; 13:e1006899. [PMID: 28715449 PMCID: PMC5536353 DOI: 10.1371/journal.pgen.1006899] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/31/2017] [Accepted: 06/27/2017] [Indexed: 11/19/2022] Open
Abstract
Transcription of the several hundred of mouse and human Ribosomal RNA (rRNA) genes accounts for the majority of RNA synthesis in the cell nucleus and is the determinant of cytoplasmic ribosome abundance, a key factor in regulating gene expression. The rRNA genes, referred to globally as the rDNA, are clustered as direct repeats at the Nucleolar Organiser Regions, NORs, of several chromosomes, and in many cells the active repeats are transcribed at near saturation levels. The rDNA is also a hotspot of recombination and chromosome breakage, and hence understanding its control has broad importance. Despite the need for a high level of rDNA transcription, typically only a fraction of the rDNA is transcriptionally active, and some NORs are permanently silenced by CpG methylation. Various chromatin-remodelling complexes have been implicated in counteracting silencing to maintain rDNA activity. However, the chromatin structure of the active rDNA fraction is still far from clear. Here we have combined a high-resolution ChIP-Seq protocol with conditional inactivation of key basal factors to better understand what determines active rDNA chromatin. The data resolve questions concerning the interdependence of the basal transcription factors, show that preinitiation complex formation is driven by the architectural factor UBF (UBTF) independently of transcription, and that RPI termination and release corresponds with the site of TTF1 binding. They further reveal the existence of an asymmetric Enhancer Boundary Complex formed by CTCF and Cohesin and flanked upstream by phased nucleosomes and downstream by an arrested RNA Polymerase I complex. We find that the Enhancer Boundary Complex is the only site of active histone modification in the 45kbp rDNA repeat. Strikingly, it not only delimits each functional rRNA gene, but also is stably maintained after gene inactivation and the re-establishment of surrounding repressive chromatin. Our data define a poised state of rDNA chromatin and place the Enhancer Boundary Complex as the likely entry point for chromatin remodelling complexes.
Collapse
Affiliation(s)
- Chelsea Herdman
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, Canada
| | - Jean-Clement Mars
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, Canada
| | - Victor Y. Stefanovsky
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
| | - Michel G. Tremblay
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
| | - Marianne Sabourin-Felix
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, Canada
| | - Helen Lindsay
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zürich, Zürich, Switzerland
| | - Mark D. Robinson
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
- SIB Swiss Institute of Bioinformatics, University of Zürich, Zürich, Switzerland
| | - Tom Moss
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Québec, Canada
- * E-mail:
| |
Collapse
|
36
|
Pruitt SC, Qin M, Wang J, Kunnev D, Freeland A. A Signature of Genomic Instability Resulting from Deficient Replication Licensing. PLoS Genet 2017; 13:e1006547. [PMID: 28045896 PMCID: PMC5242545 DOI: 10.1371/journal.pgen.1006547] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 01/18/2017] [Accepted: 12/19/2016] [Indexed: 11/23/2022] Open
Abstract
Insufficient licensing of DNA replication origins has been shown to result in genome instability, stem cell deficiency, and cancers. However, it is unclear whether the DNA damage resulting from deficient replication licensing occurs generally or if specific sites are preferentially affected. To map locations of ongoing DNA damage in vivo, the DNAs present in red blood cell micronuclei were sequenced. Many micronuclei are the product of DNA breaks that leave acentromeric remnants that failed to segregate during mitosis and should reflect the locations of breaks. To validate the approach we show that micronuclear sequences identify known common fragile sites under conditions that induce breaks at these locations (hydroxyurea). In MCM2 deficient mice a different set of preferred breakage sites is identified that includes the tumor suppressor gene Tcf3, which is known to contribute to T-lymphocytic leukemias that arise in these mice, and the 45S rRNA gene repeats. Many RBC micronuclei result from double strand DNA breaks that give rise to acentromeric chromosomal fragments that fail to incorporate into nuclei during mitosis and consequently remain in the cell following enucleation. Here, RBC micronuclear DNA is sequenced (Mic-Seq) to define the locations of breaks genome-wide and this assay is used to study ongoing genome instability resulting from insufficient DNA replication origin licensing. Using a mouse model, we show that there is increased instability at discrete sites across the genome, which include genes that are recurrently deleted in the T-lymphocytic leukemias that eventually arise in these mice. Mic-Seq may provide an effective means of predicting locations that are susceptible to genetic damage and these predictions may have prognostic value.
Collapse
Affiliation(s)
- Steven C. Pruitt
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
- * E-mail:
| | - Maochun Qin
- Department of Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Jianmin Wang
- Department of Biostatistics and Bioinformatics, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Dimiter Kunnev
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| | - Amy Freeland
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York, United States of America
| |
Collapse
|
37
|
Gomes Júnior RG, Schneider CH, de Lira T, Carvalho NDM, Feldberg E, da Silva MNF, Gross MC. Intense genomic reorganization in the genus Oecomys (Rodentia, Sigmodontinae): comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon. COMPARATIVE CYTOGENETICS 2016; 10:401-426. [PMID: 27830049 PMCID: PMC5088352 DOI: 10.3897/compcytogen.v10i3.8306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/29/2016] [Indexed: 05/31/2023]
Abstract
Oecomys Thomas, 1906 is one of the most diverse and widely distributed genera within the tribe Oryzomyini. At least sixteen species in this genus have been described to date, but it is believed this genus contains undescribed species. Morphological, molecular and cytogenetic study has revealed an uncertain taxonomic status for several Oecomys species, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genus Oecomys in the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized: Oecomys auyantepui (Tate, 1939), Oecomys bicolor (Tomes, 1860) and Oecomys rutilus (Anthony, 1921). COI sequence analysis grouped Oecomys auyantepui, Oecomys bicolor and Oecomys rutilus specimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data for Oecomys auyantepui revealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism while Oecomys bicolor exhibited 2n=80/NFa=142 and Oecomys rutilus 2n=54/NFa=90. The distribution of constitutive heterochromatin followed a species-specific pattern. Interspecific variation was evident in the chromosomal location and number of 18S rDNA loci. However, not all loci showed signs of activity. All three species displayed a similar pattern for 5S rDNA, with only one pair carrying this locus. Interstitial telomeric sites were found only in Oecomys auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number of Oecomys species and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas.
Collapse
Affiliation(s)
- Renan Gabriel Gomes Júnior
- Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil
| | - Carlos Henrique Schneider
- Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil
| | - Thatianna de Lira
- Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Zip Code 69077-000, Manaus, AM, Brazil
| | - Natália Dayane Moura Carvalho
- Universidade Federal do Amazonas, Instituto de Ciências Biológicas, Departamento de Genética, Laboratório de Citogenômica Animal, Av. General Rodrigo Otávio, 3000, Japiim, Zip code 69077-000 Manaus, AM, Brazil
| | - Eliana Feldberg
- Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936 Zip Code 69077-000, Manaus, AM, Brazil
| | | | - Maria Claudia Gross
- Universidade Federal da Integração Latino Americana, Laboratório de Genética, Av. Tarquínio Joslin dos Santos, 1000, Jardim Universitário, Zip code 85857-190, Foz do Iguaçu, PR, Brazil
| |
Collapse
|
38
|
Zhao Q, Wu Y, Shan Z, Bai G, Wang Z, Hu J, Liu L, Li T, Shen J, Lei L. Serum starvation-induced cell cycle synchronization stimulated mouse rDNA transcription reactivation during somatic cell reprogramming into iPSCs. Stem Cell Res Ther 2016; 7:112. [PMID: 27515169 PMCID: PMC4981958 DOI: 10.1186/s13287-016-0369-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/18/2016] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND rDNA, the genes encoding ribosomal RNA (rRNA), is highly demanded for ribosome production and protein synthesis in growing cells such as pluripotent stem cells. rDNA transcription activity varies between cell types, metabolism conditions, and specific environmental challenges. Embryonic stem cells (ESCs), partially reprogrammed cells, and somatic cells reveal different epigenetic signatures, including rDNA epigenetic marks. rDNA epigenetic characteristic resetting is not quite clear during induced pluripotent stem cell (iPSC) generation. Little is known that whether the different rDNA epigenetic status in donor cells will result in different rDNA transcription activities, and furthermore affect reprogramming efficiency. METHODS We utilized serum starvation-synchronized mouse embryonic fibroblasts (MEFs) to generate S-iPSCs. Both MEFs and serum-refeeding MEFs (S-MEFs) were reprogrammed to a pluripotent state. rDNA-related genes, UBF proteins, and rDNA methylation levels were detected during the MEF and S-MEF cell reprogramming process. RESULTS We demonstrated that, after transient inhibition, retroviral induced rRNA transcriptional activity was reprogrammed towards a pluripotent state. Serum starvation would stimulate rDNA transcription reactivation during somatic cell reprogramming. Serum starvation improved the methylation status of donor cells at rRNA gene promoter regions. CONCLUSIONS Our results provide insight into regulation of rDNA transcriptional activity during somatic cell reprogramming and allow for comparison of rDNA regulation patterns between iPSCs and S-iPSCs. Eventually, regulation of rDNA transcriptional activity will benefit partially reprogrammed cells to overcome the epigenetic barrier to pluripotency.
Collapse
Affiliation(s)
- Qiaoshi Zhao
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Yanshuang Wu
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Zhiyan Shan
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Guangyu Bai
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Zhendong Wang
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Jing Hu
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Li Liu
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Tong Li
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Jingling Shen
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China
| | - Lei Lei
- Department of Histology and Embryology, Harbin Medical University, Xuefu Road 194#, Nangang District, Harbin, 150081, China.
| |
Collapse
|
39
|
Abstract
Nucleoli form around tandem arrays of a ribosomal gene repeat, termed nucleolar organizer regions (NORs). During metaphase, active NORs adopt a characteristic undercondensed morphology. Recent evidence indicates that the HMG-box-containing DNA-binding protein UBF (upstream binding factor) is directly responsible for this morphology and provides a mitotic bookmark to ensure rapid nucleolar formation beginning in telophase in human cells. This is likely to be a widely employed strategy, as UBF is present throughout metazoans. In higher eukaryotes, NORs are typically located within regions of chromosomes that form perinucleolar heterochromatin during interphase. Typically, the genomic architecture of NORs and the chromosomal regions within which they lie is very poorly described, yet recent evidence points to a role for context in their function. In Arabidopsis, NOR silencing appears to be controlled by sequences outside the rDNA (ribosomal DNA) array. Translocations reveal a role for context in the expression of the NOR on the X chromosome in Drosophila Recent work has begun on characterizing the genomic architecture of human NORs. A role for distal sequences located in perinucleolar heterochromatin has been inferred, as they exhibit a complex transcriptionally active chromatin structure. Links between rDNA genomic stability and aging in Saccharomyces cerevisiae are now well established, and indications are emerging that this is important in aging and replicative senescence in higher eukaryotes. This, combined with the fact that rDNA arrays are recombinational hot spots in cancer cells, has focused attention on DNA damage responses in NORs. The introduction of DNA double-strand breaks into rDNA arrays leads to a dramatic reorganization of nucleolar structure. Damaged rDNA repeats move from the nucleolar interior to form caps at the nucleolar periphery, presumably to facilitate repair, suggesting that the chromosomal context of human NORs contributes to their genomic stability. The inclusion of NORs and their surrounding chromosomal environments in future genome drafts now becomes a priority.
Collapse
Affiliation(s)
- Brian McStay
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| |
Collapse
|
40
|
Abstract
Heterochromatin is the transcriptionally repressed portion of eukaryotic chromatin that maintains a condensed appearance throughout the cell cycle. At sites of ribosomal DNA (rDNA) heterochromatin, epigenetic states contribute to gene silencing and genome stability, which are required for proper chromosome segregation and a normal life span. Here, we focus on recent advances in the epigenetic regulation of rDNA silencing in Saccharomyces cerevisiae and in mammals, including regulation by several histone modifications and several protein components associated with the inner nuclear membrane within the nucleolus. Finally, we discuss the perturbations of rDNA epigenetic pathways in regulating cellular aging and in causing various types of diseases.
Collapse
|
41
|
Agrawal S, Ganley ARD. Complete Sequence Construction of the Highly Repetitive Ribosomal RNA Gene Repeats in Eukaryotes Using Whole Genome Sequence Data. Methods Mol Biol 2016; 1455:161-181. [PMID: 27576718 DOI: 10.1007/978-1-4939-3792-9_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The ribosomal RNA genes (rDNA) encode the major rRNA species of the ribosome, and thus are essential across life. These genes are highly repetitive in most eukaryotes, forming blocks of tandem repeats that form the core of nucleoli. The primary role of the rDNA in encoding rRNA has been long understood, but more recently the rDNA has been implicated in a number of other important biological phenomena, including genome stability, cell cycle, and epigenetic silencing. Noncoding elements, primarily located in the intergenic spacer region, appear to mediate many of these phenomena. Although sequence information is available for the genomes of many organisms, in almost all cases rDNA repeat sequences are lacking, primarily due to problems in assembling these intriguing regions during whole genome assemblies. Here, we present a method to obtain complete rDNA repeat unit sequences from whole genome assemblies. Limitations of next generation sequencing (NGS) data make them unsuitable for assembling complete rDNA unit sequences; therefore, the method we present relies on the use of Sanger whole genome sequence data. Our method makes use of the Arachne assembler, which can assemble highly repetitive regions such as the rDNA in a memory-efficient way. We provide a detailed step-by-step protocol for generating rDNA sequences from whole genome Sanger sequence data using Arachne, for refining complete rDNA unit sequences, and for validating the sequences obtained. In principle, our method will work for any species where the rDNA is organized into tandem repeats. This will help researchers working on species without a complete rDNA sequence, those working on evolutionary aspects of the rDNA, and those interested in conducting phylogenetic footprinting studies with the rDNA.
Collapse
Affiliation(s)
- Saumya Agrawal
- Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland, 0632, New Zealand.
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
| | - Austen R D Ganley
- Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland, 0632, New Zealand.
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
| |
Collapse
|
42
|
Swinger RNAs with sharp switches between regular transcription and transcription systematically exchanging ribonucleotides: Case studies. Biosystems 2015; 135:1-8. [PMID: 26163926 DOI: 10.1016/j.biosystems.2015.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 07/02/2015] [Accepted: 07/06/2015] [Indexed: 11/20/2022]
Abstract
During RNA transcription, DNA nucleotides A,C,G, T are usually matched by ribonucleotides A, C, G and U. However occasionally, this rule does not apply: transcript-DNA homologies are detectable only assuming systematic exchanges between ribonucleotides. Nine symmetric (X ↔ Y, e.g. A ↔ C) and fourteen asymmetric (X ↔ Y ↔ Z, e.g. A ↔ C ↔ G) exchanges exist, called swinger transcriptions. Putatively, polymerases occasionally stabilize in unspecified swinger conformations, possibly similar to transient conformations causing punctual misinsertions. This predicts chimeric transcripts, part regular, part swinger-transformed, reflecting polymerases switching to swinger polymerization conformation(s). Four chimeric Genbank transcripts (three from human mitochondrion and one murine cytosolic) are described here: (a) the 5' and 3' extremities reflect regular polymerization, the intervening sequence exchanges systematically between ribonucleotides (swinger rule G ↔ U, transcript (1), with sharp switches between regular and swinger sequences; (b) the 5' half is 'normal', the 3' half systematically exchanges ribonucleotides (swinger rule C ↔ G, transcript (2), with an intercalated sequence lacking homology; (c) the 3' extremity fits A ↔ G exchanges (10% of transcript length), the 5' half follows regular transcription; the intervening region seems a mix of regular and A ↔ G transcriptions (transcript 3); (d) murine cytosolic transcript 4 switches to A ↔ U + C ↔ G, and is fused with A ↔ U + C ↔ G swinger transformed precursor rRNA. In (c), each concomitant transcript 5' and 3' extremities match opposite genome strands. Transcripts 3 and 4 combine transcript fusions with partial swinger transcriptions. Occasional (usually sharp) switches between regular and swinger transcriptions reveal greater coding potential than detected until now, suggest stable polymerase swinger conformations.
Collapse
|
43
|
Concerted copy number variation balances ribosomal DNA dosage in human and mouse genomes. Proc Natl Acad Sci U S A 2015; 112:2485-90. [PMID: 25583482 DOI: 10.1073/pnas.1416878112] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Tandemly repeated ribosomal DNA (rDNA) arrays are among the most evolutionary dynamic loci of eukaryotic genomes. The loci code for essential cellular components, yet exhibit extensive copy number (CN) variation within and between species. CN might be partly determined by the requirement of dosage balance between the 5S and 45S rDNA arrays. The arrays are nonhomologous, physically unlinked in mammals, and encode functionally interdependent RNA components of the ribosome. Here we show that the 5S and 45S rDNA arrays exhibit concerted CN variation (cCNV). Despite 5S and 45S rDNA elements residing on different chromosomes and lacking sequence similarity, cCNV between these loci is strong, evolutionarily conserved in humans and mice, and manifested across individual genotypes in natural populations and pedigrees. Finally, we observe that bisphenol A induces rapid and parallel modulation of 5S and 45S rDNA CN. Our observations reveal a novel mode of genome variation, indicate that natural selection contributed to the evolution and conservation of cCNV, and support the hypothesis that 5S CN is partly determined by the requirement of dosage balance with the 45S rDNA array. We suggest that human disease variation might be traced to disrupted rDNA dosage balance in the genome.
Collapse
|
44
|
Sánchez-Martín FJ, Lindquist DM, Landero-Figueroa J, Zhang X, Chen J, Cecil KM, Medvedovic M, Puga A. Sex- and tissue-specific methylome changes in brains of mice perinatally exposed to lead. Neurotoxicology 2014; 46:92-100. [PMID: 25530354 DOI: 10.1016/j.neuro.2014.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 11/29/2022]
Abstract
Changes in DNA methylation and subsequent changes in gene expression regulation are the hallmarks of age- and tissue-dependent epigenetic drift and plasticity resulting from the combinatorial integration of genetic determinants and environmental cues. To determine whether perinatal lead exposure caused persistent DNA methylation changes in target tissues, we exposed mouse dams to 0, 3 or 30 ppm of lead acetate in drinking water for a period extending from 2 months prior to mating, through gestation, until weaning of pups at postnatal day-21, and analyzed whole-genome DNA methylation in brain cortex and hippocampus of 2-month old exposed and unexposed progeny. Lead exposure resulted in hypermethylation of three differentially methylated regions in the hippocampus of females, but not males. These regions mapped to Rn4.5s, Sfi1, and Rn45s loci in mouse chromosomes 2, 11 and 17, respectively. At a conservative fdr<0.001, 1623 additional CpG sites were differentially methylated in female hippocampus, corresponding to 117 unique genes. Sixty of these genes were tested for mRNA expression and showed a trend toward negative correlation between mRNA expression and methylation in exposed females but not males. No statistically significant methylome changes were detected in male hippocampus or in cortex of either sex. We conclude that exposure to lead during embryonic life, a time when the organism is most sensitive to environmental cues, appears to have a sex- and tissue-specific effect on DNA methylation that may produce pathological or physiological deviations from the epigenetic plasticity operative in unexposed mice.
Collapse
Affiliation(s)
- Francisco Javier Sánchez-Martín
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Diana M Lindquist
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Julio Landero-Figueroa
- Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Xiang Zhang
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jing Chen
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kim M Cecil
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mario Medvedovic
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Alvaro Puga
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| |
Collapse
|
45
|
Abstract
The transcription of rRNA is critical to all living cells and is tightly controlled at the level of chromatin structure. Although the widespread adoption of genomic technologies including chromatin immunoprecipitation with massively parallel short-read sequencing (ChIP-seq) has allowed for the interrogation of chromatin structure on a genome-wide scale, until recently rDNA has not been analyzed by this technique. We extended genomic analysis of rDNA to mouse (Mus musculus), in which rDNA is similar in structure but highly divergent in sequence compared with human rDNA. Comparison of rDNA histone marks between mouse embryonic stem cells (mESCs) and more differentiated mouse cell types revealed differences between pluripotent and differentiated states. We also observed substantial divergence in rDNA histone modification patterns between mESCs and human embryonic stem cells (hESCs). Surprisingly, we found that the pluripotency factor OCT4 was bound to rDNA in similar patterns in mESCs and hESCs. Extending this analysis, we found that an additional 17 pluripotency-associated factors were bound to rDNA in mESCs, suggesting novel modes of rDNA regulation in pluripotent cells. Taken together, our results provide a detailed view of rDNA chromatin structure in an important model system and enable high-resolution comparison of rDNA regulation between mouse and human.
Collapse
|
46
|
Gene-trap mutagenesis using Mol/MSM-1 embryonic stem cells from MSM/Ms mice. Mamm Genome 2013; 24:228-39. [DOI: 10.1007/s00335-013-9452-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 03/12/2013] [Indexed: 12/12/2022]
|
47
|
Wei H, Zhou B, Zhang F, Tu Y, Hu Y, Zhang B, Zhai Q. Profiling and identification of small rDNA-derived RNAs and their potential biological functions. PLoS One 2013; 8:e56842. [PMID: 23418607 PMCID: PMC3572043 DOI: 10.1371/journal.pone.0056842] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 01/14/2013] [Indexed: 12/13/2022] Open
Abstract
Small non-coding RNAs constitute a large family of regulatory molecules with diverse functions. Notably, some small non-coding RNAs matched to rDNA have been identified as qiRNAs and small guide RNAs involved in various biological processes. However, a large number of small rDNA-derived RNAs (srRNAs) are usually neglected and yet to be investigated. We systematically investigated srRNAs using small RNA datasets generated by high-throughput sequencing, and found srRNAs are mainly mapped to rRNA coding regions in sense direction. The datasets from immunoprecipitation and high-throughput sequencing demonstrate that srRNAs are co-immunoprecipitated with Argonaute (AGO) proteins. Furthermore, the srRNA expression profile in mouse liver is affected by diabetes. Overexpression or inhibition of srRNAs in cultured cells shows that srRNAs are involved in various signaling pathways. This study presents a global view of srRNAs in total small RNA and AGO protein complex from different species, and demonstrates that srRNAs are correlated with diabetes, and involved in some biological processes. These findings provide new insights into srRNAs and their functions in various physiological and pathological processes.
Collapse
Affiliation(s)
- Haibin Wei
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Ben Zhou
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Fang Zhang
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Yanyang Tu
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Yanan Hu
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Baoguo Zhang
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Qiwei Zhai
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People’s Republic of China
- * E-mail:
| |
Collapse
|
48
|
Britton-Davidian J, Cazaux B, Catalan J. Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights. Heredity (Edinb) 2011; 108:68-74. [PMID: 22086078 DOI: 10.1038/hdy.2011.105] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Variation in the number and chromosomal location of nucleolar organizer regions (NORs) was studied in the house mouse, Mus musculus (2n=40). From an origin in Western Asia, this species colonized the Middle East, Europe and Asia. This expansion was accompanied by diversification into five subspecies. NOR diversity was revealed by fluorescence in situ hybridization using 18S and 28S probes on specimens spanning Asia to Western Europe. The results showed that the house mouse genome possessed a large number of NOR-bearing autosomes and a surprisingly high rate of polymorphism for the presence/absence of rRNA genes on all these chromosomes. All NOR sites were adjacent to the centromere except for two that were telomeric. Subspecific differentiation established from the NOR frequency data was concordant with the overall pattern of radiation proposed from molecular studies, but highlighted several discrepancies that need to be further addressed. NOR diversity in M. musculus consisted of a large number of polymorphic NORs that were common to at least two subspecies, and a smaller number of NORs that were unique to one subspecies. The most parsimonious scenario argues in favor of a subspecific differentiation by lineage sorting of ancestral NOR polymorphisms; only the unique NORs would have appeared by inter-chromosomal transposition, except for the two telomeric ones that may have originated by hybridization with another species. Such a scenario provides an alternative view from the one prevailing in most systematic and phylogenetic analyses that NORs have a high transposition rate due to concerted evolution of rRNA genes.
Collapse
Affiliation(s)
- J Britton-Davidian
- Institut des Sciences de l'Evolution, Université Montpellier 2, Montpellier cedex, France.
| | | | | |
Collapse
|
49
|
Polzikov MA, Veĭko NN, Zharskaia OO, Magoulas KB, Zatsepina OV. [Overexpression of the nucleolar protein SURF-6 in mouse fibroblasts NIH/3T3 leads to stabilisation of intragenic transcribed spacers of the pre-rRNA]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2010; 36:661-71. [PMID: 21063453 DOI: 10.1134/s1068162010050092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SURF-6 is an evolutionary conserved nucleolar protein that is required for maintenance of cell viability, but its functional significance in mammals still remains illusive. In the present work we examined effects of SURF-6 overexpression in mouse NIH/3T3 fibroblasts transfected with two plasmids. The plasmid pUHrT62-1 encodes a tetracycline-dependant trans-activator, the protein rtTA, the plasmid pBI-SURF6--the genes of EGFP (enhanced green fluorescent protein) and of mouse SURF-6 which expression was controlled by the rtTA-responsive bi-directorial promoter. Western blot analysis showed that the SURF-6 level was severely augmented in cells transfected with pUHrT62-1 and pBI-SURF6 and incubated with the inducer--doxycycline opposed to the transfected but not-induced cells. The increase of SURF-6 was observed in 24 and 48 h after adding the inducer doxycycline. Dot-hybridization of isolated RNA with biotinilated oligonucleotide probes to various regions of mouse primarily pre-rRNA transcripts showed that overexpression of SURF-6 enhanced levels of the second intragenic transcribed spacer ITS2 in about seven folds and of the 5' external transcribed spacer 5'ETS in two folds. Amounts of fragments corresponding to 18S, 5.8S and 28S rRNA remained almost unchanged. These observations for the first time demonstrated that mammalian SURF-6 helps to stabilize or prevents premature cleavage of the pre-rRNA intragenic transcribed spacers, particularly of ITS2, similar to its homologue in S. cerevisiae the protein Rrp14. Today metazoan proteins that play a similar role in ribosome biogenesis, are not described.
Collapse
|
50
|
Chang KD, Fang SA, Chang FC, Chung MC. Chromosomal conservation and sequence diversity of ribosomal RNA genes of two distant Oryza species. Genomics 2010; 96:181-90. [PMID: 20580815 DOI: 10.1016/j.ygeno.2010.05.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Revised: 04/30/2010] [Accepted: 05/18/2010] [Indexed: 01/31/2023]
Abstract
Contrary to the chromosomal polymorphism of 45S ribosomal genes (45S rDNA) loci in other Oryza species, each of Oryza australiensis and Oryza brachyantha has only one 45S rDNA locus at the most conserved position of 45S rDNAs in Oryza. O. australiensis and O. brachyantha are known phylogenetically distant and have extremely different genome sizes among diploid Oryza species. This study reveals that the sequences and organizations of intergenic spacer (IGS) for 45S rDNA of both O. australiensis and O. brachyantha are different from other Oryza species. The IGS of O. australiensis contains 13 tandem repeats and only one transcriptional initiation site, while there are four tandem repeats and three transcriptional initiation sites in the IGS of O. brachyantha. Our results suggest different evolution processes of orthologous rDNA loci in the genus Oryza. Here we also demonstrate an efficient strategy to study locus-specific IGS before whole genome sequences data are available.
Collapse
Affiliation(s)
- Kwei-Duan Chang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | | | | | | |
Collapse
|