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Sharma D, Denmat SHL, Matzke NJ, Hannan K, Hannan RD, O'Sullivan JM, Ganley ARD. A new method for determining ribosomal DNA copy number shows differences between Saccharomyces cerevisiae populations. Genomics 2022; 114:110430. [PMID: 35830947 DOI: 10.1016/j.ygeno.2022.110430] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/23/2022] [Accepted: 07/04/2022] [Indexed: 11/26/2022]
Abstract
Ribosomal DNA genes (rDNA) encode the major ribosomal RNAs and in eukaryotes typically form tandem repeat arrays. Species have characteristic rDNA copy numbers, but there is substantial intra-species variation in copy number that results from frequent rDNA recombination. Copy number differences can have phenotypic consequences, however difficulties in quantifying copy number mean we lack a comprehensive understanding of how copy number evolves and the consequences. Here we present a genomic sequence read approach to estimate rDNA copy number based on modal coverage to help overcome limitations with existing mean coverage-based approaches. We validated our method using Saccharomyces cerevisiae strains with known rDNA copy numbers. Application of our pipeline to a global sample of S. cerevisiae isolates showed that different populations have different rDNA copy numbers. Our results demonstrate the utility of the modal coverage method, and highlight the high level of rDNA copy number variation within and between populations.
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Affiliation(s)
- Diksha Sharma
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Sylvie Hermann-Le Denmat
- School of Biological Sciences, University of Auckland, Auckland, New Zealand; Ecole Normale Supérieure, PSL Research University, F-75005 Paris, France
| | - Nicholas J Matzke
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Katherine Hannan
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, ACT 2601, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ross D Hannan
- ACRF Department of Cancer Biology and Therapeutics, The John Curtin School of Medical Research, ACT 2601, Australia; Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Division of Research, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3168, Australia
| | - Justin M O'Sullivan
- Liggins Institute, University of Auckland, Auckland, New Zealand; Maurice Wilkins Center, University of Auckland, New Zealand; MRC Lifecourse Unit, University of Southampton, United Kingdom; Brain Research New Zealand, The University of Auckland, Auckland, New Zealand
| | - Austen R D Ganley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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Abstract
In human cells, ribosomal DNA (rDNA) is arranged in ten clusters of multiple tandem repeats. Each repeat is usually described as consisting of two parts: the 13 kb long ribosomal part, containing three genes coding for 18S, 5.8S and 28S RNAs of the ribosomal particles, and the 30 kb long intergenic spacer (IGS). However, this standard scheme is, amazingly, often altered as a result of the peculiar instability of the locus, so that the sequence of each repeat and the number of the repeats in each cluster are highly variable. In the present review, we discuss the causes and types of human rDNA instability, the methods of its detection, its distribution within the locus, the ways in which it is prevented or reversed, and its biological significance. The data of the literature suggest that the variability of the rDNA is not only a potential cause of pathology, but also an important, though still poorly understood, aspect of the normal cell physiology.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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.
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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.
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Margulis M, Danielli A. Rapid and Sensitive Detection of Repetitive Nucleic Acid Sequences Using Magnetically Modulated Biosensors. ACS Omega 2019; 4:11749-11755. [PMID: 31460281 PMCID: PMC6682110 DOI: 10.1021/acsomega.9b01071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/05/2019] [Indexed: 05/11/2023]
Abstract
Repetitive DNA sequences are abundant in the genome of most biological species. These sequences are naturally "preamplified", which makes them a preferential target for a variety of biological assays. Current methods to detect specific DNA sequences are based on the quantitative polymerase chain reaction (PCR), which relies on target amplification by Taq polymerase and uses a fluorescent resonance energy transfer (FRET)-based probe. Here, to rapidly detect a repetitive DNA sequence, we combine a highly sensitive magnetic modulation biosensing (MMB) system and a modified double-quenched FRET-based probe. The high numbers of copies of the female-specific XhoI sequence of the domestic chicken (Gallus gallus), combined with the low background fluorescence levels of the modified double-quenched probe and the high sensitivity of the MMB system, allow us to determine the chick sex in ovo within 13 min, with 100% sensitivity and specificity. Compared to quantitative PCR, the presented assay is 4-9 times faster. More broadly, by specifically tailoring the primers and probe, the proposed assay can detect any target DNA sequence, either repetitive or nonrepetitive.
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Vacík T, Kereïche S, Raška I, Cmarko D, Smirnov E. Life time of some RNA products of rDNA intergenic spacer in HeLa cells. Histochem Cell Biol 2019; 152:271-80. [DOI: 10.1007/s00418-019-01804-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2019] [Indexed: 12/21/2022]
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Porokhovnik L, Gerton JL. Ribosomal DNA-connecting ribosome biogenesis and chromosome biology. Chromosome Res 2019; 27:1-3. [PMID: 30663012 DOI: 10.1007/s10577-018-9601-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 01/08/2023]
Abstract
Ribosomal DNA, the topic of this special issue, has long fascinated biologists. The RNA products of the ribosomal DNA are the ribosomal RNAs that are part of the ribosome. In this special issue, we focus on the sequence, molecular organization, repair, stability, copy number, and peculiar genetics of this region of the genome. The locus can impact not only the translational capability of cells, but also genome organization, stability and integrity, providing a link between translation and chromosome biology.
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Abstract
Ribosomal RNA gene repeats (rDNA) encode ribosomal RNA, a major component of ribosomes. Ribosome biogenesis is central to cellular metabolic regulation, and several diseases are associated with rDNA dysfunction, notably cancer, However, its highly repetitive nature has severely limited characterization of the elements responsible for rDNA function. Here we make use of phylogenetic footprinting to provide a comprehensive list of novel, potentially functional elements in the human rDNA. Complete rDNA sequences for six non-human primate species were constructed using de novo whole genome assemblies. These new sequences were used to determine the conservation profile of the human rDNA, revealing 49 conserved regions in the rDNA intergenic spacer (IGS). To provide insights into the potential roles of these conserved regions, the conservation profile was integrated with functional genomics datasets. We find two major zones that contain conserved elements characterised by enrichment of transcription-associated chromatin factors, and transcription. Conservation of some IGS transcripts in the apes underpins the potential functional significance of these transcripts and the elements controlling their expression. Our results characterize the conservation landscape of the human IGS and suggest that noncoding transcription and chromatin elements are conserved and important features of this unique genomic region.
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Affiliation(s)
- Saumya Agrawal
- Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
| | - Austen R. D. Ganley
- Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
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Porokhovnik LN, Lyapunova NA. Dosage effects of human ribosomal genes (rDNA) in health and disease. Chromosome Res 2018; 27:5-17. [PMID: 30343462 DOI: 10.1007/s10577-018-9587-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 09/07/2018] [Accepted: 09/24/2018] [Indexed: 02/02/2023]
Abstract
Human ribosomal RNA genes encoding a pre-transcript of the three major ribosomal RNA (18S, 5.8S, and 28S rRNA) are tandemly repeated in human genome. Their total copy number varies from 250 to 670 per diploid genome with a mean of approximately 420 copies, but only a fraction of them is transcriptionally active. The functional consequences of human ribosomal RNA gene dosage are not widely known and often assumed to be negligible. Here, we review the facts of rRNA gene dosage effects on normal growth and aging, stress resistance of healthy individuals, and survivability of patients with chromosomal abnormalities, as well as on the risk and severity of some multifactorial diseases with proven genetic predisposition. An original hypothesis that rRNA gene dosage can be a modulating factor involved in the pathogenesis of schizophrenia and rheumatoid arthritis is put forward.
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Affiliation(s)
- L N Porokhovnik
- Research Centre for Medical Genetics, 1 Moskvorechie str, Moscow, 115478, Russia.
| | - N A Lyapunova
- Research Centre for Medical Genetics, 1 Moskvorechie str, Moscow, 115478, Russia
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Kim JH, Dilthey AT, Nagaraja R, Lee HS, Koren S, Dudekula D, Wood Iii WH, Piao Y, Ogurtsov AY, Utani K, Noskov VN, Shabalina SA, Schlessinger D, Phillippy AM, Larionov V. Variation in human chromosome 21 ribosomal RNA genes characterized by TAR cloning and long-read sequencing. Nucleic Acids Res 2018; 46:6712-6725. [PMID: 29788454 PMCID: PMC6061828 DOI: 10.1093/nar/gky442] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/08/2018] [Indexed: 12/31/2022] Open
Abstract
Despite the key role of the human ribosome in protein biosynthesis, little is known about the extent of sequence variation in ribosomal DNA (rDNA) or its pre-rRNA and rRNA products. We recovered ribosomal DNA segments from a single human chromosome 21 using transformation-associated recombination (TAR) cloning in yeast. Accurate long-read sequencing of 13 isolates covering ∼0.82 Mb of the chromosome 21 rDNA complement revealed substantial variation among tandem repeat rDNA copies, several palindromic structures and potential errors in the previous reference sequence. These clones revealed 101 variant positions in the 45S transcription unit and 235 in the intergenic spacer sequence. Approximately 60% of the 45S variants were confirmed in independent whole-genome or RNA-seq data, with 47 of these further observed in mature 18S/28S rRNA sequences. TAR cloning and long-read sequencing enabled the accurate reconstruction of multiple rDNA units and a new, high-quality 44 838 bp rDNA reference sequence, which we have annotated with variants detected from chromosome 21 of a single individual. The large number of variants observed reveal heterogeneity in human rDNA, opening up the possibility of corresponding variations in ribosome dynamics.
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MESH Headings
- Animals
- Cell Line
- Chromosomes, Human, Pair 21
- Cloning, Molecular
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/isolation & purification
- DNA, Ribosomal Spacer/chemistry
- Genes, rRNA
- Genetic Variation
- Humans
- Mice
- Nucleic Acid Conformation
- Nucleolus Organizer Region/chemistry
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/metabolism
- Sequence Analysis, DNA
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Affiliation(s)
- Jung-Hyun Kim
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD 20892, USA
| | - Alexander T Dilthey
- National Human Genome Research Institute, Computational and Statistical Genomics Branch, Bethesda, MD 20892, USA
| | - Ramaiah Nagaraja
- National Institute on Aging, Laboratory of Genetics and Genomics, Baltimore, MD 21224, USA
| | - Hee-Sheung Lee
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD 20892, USA
| | - Sergey Koren
- National Human Genome Research Institute, Computational and Statistical Genomics Branch, Bethesda, MD 20892, USA
| | - Dawood Dudekula
- National Institute on Aging, Laboratory of Genetics and Genomics, Baltimore, MD 21224, USA
| | - William H Wood Iii
- National Institute on Aging, Laboratory of Genetics and Genomics, Baltimore, MD 21224, USA
| | - Yulan Piao
- National Institute on Aging, Laboratory of Genetics and Genomics, Baltimore, MD 21224, USA
| | - Aleksey Y Ogurtsov
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20892, USA
| | - Koichi Utani
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD 20892, USA
| | - Vladimir N Noskov
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD 20892, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20892, USA
| | - David Schlessinger
- National Institute on Aging, Laboratory of Genetics and Genomics, Baltimore, MD 21224, USA
| | - Adam M Phillippy
- National Human Genome Research Institute, Computational and Statistical Genomics Branch, Bethesda, MD 20892, USA
| | - Vladimir Larionov
- National Cancer Institute, Developmental Therapeutics Branch, Bethesda, MD 20892, USA
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Campbell MA, Tapper BA, Simpson WR, Johnson RD, Mace W, Ram A, Lukito Y, Dupont PY, Johnson LJ, Scott DB, Ganley ARD, Cox MP. Epichloë hybrida, sp. nov., an emerging model system for investigating fungal allopolyploidy. Mycologia 2018; 109:715-729. [PMID: 29370579 DOI: 10.1080/00275514.2017.1406174] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Endophytes of the genus Epichloë (Clavicipitaceae, Ascomycota) frequently occur within cool-season grasses and form interactions with their hosts that range from mutualistic to antagonistic. Many Epichloë species have arisen via interspecific hybridization, resulting in species with two or three subgenomes that retain all or nearly all of their original parental genomes, a process termed allopolyploidization. Here, we characterize Epichloë hybrida, sp. nov., a mutualistic species that has increasingly become a model system for investigating allopolyploidy in fungi. The Epichloë species so far identified as the closest known relatives of the two progenitors of E. hybrida are E. festucae var. lolii and E. typhina. We confirm that the nuclear genome of E. hybrida contains two homeologs of most protein-coding genes from E. festucae and E. typhina, with genome-wide gene expression analysis indicating a slight bias in overall gene expression from the E. typhina subgenome. Mitochondrial DNA is detectable only from E. festucae, whereas ribosomal DNA is detectable only from E. typhina. Inheriting ribosomal DNA from just one parent might be expected to preferentially favor interactions with ribosomal proteins from the same parent, but we find that ribosomal protein genes from both parental subgenomes are nearly all expressed equally in E. hybrida. Finally, we provide a comprehensive set of resources for this model system that are intended to facilitate further study of fungal hybridization by other researchers.
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Affiliation(s)
- Matthew A Campbell
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
| | - Brian A Tapper
- b AgResearch Ltd., Grasslands Research Centre , Tennent Drive, Palmerston North 4442 , New Zealand
| | - Wayne R Simpson
- b AgResearch Ltd., Grasslands Research Centre , Tennent Drive, Palmerston North 4442 , New Zealand
| | - Richard D Johnson
- b AgResearch Ltd., Grasslands Research Centre , Tennent Drive, Palmerston North 4442 , New Zealand
| | - Wade Mace
- b AgResearch Ltd., Grasslands Research Centre , Tennent Drive, Palmerston North 4442 , New Zealand
| | - Arvina Ram
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
| | - Yonathan Lukito
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
| | - Pierre-Yves Dupont
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
| | - Linda J Johnson
- b AgResearch Ltd., Grasslands Research Centre , Tennent Drive, Palmerston North 4442 , New Zealand
| | - D Barry Scott
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
| | - Austen R D Ganley
- c School of Biological Sciences, University of Auckland , Private Bag 92019, Auckland 1142 , New Zealand
| | - Murray P Cox
- a Institute of Fundamental Sciences, Massey University , Private Bag 11 222, Palmerston North 4410 , New Zealand
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