1
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Olliff NS, Hunt MA, Paudel SS, Nguyen KN, Delcher HA, DeMeis JD, Roberts JT, Fouty BW, Audia JP, Kim JH, Borchert GM. Human YRNA 4 (HY4) plasma levels are a prognostic indicator of SARS-CoV-2 infection clinical severity. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000925. [PMID: 37662051 PMCID: PMC10474479 DOI: 10.17912/micropub.biology.000925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 09/05/2023]
Abstract
SARS-CoV-2 infection can result in a range of outcomes from asymptomatic/mild disease to severe COVID-19/fatality. In this study, we investigated the differential expression of small noncoding RNAs (sncRNAs) between patient cohorts defined by disease severity. We collected plasma samples, stratified these based on clinical outcomes, and sequenced their circulating sncRNAs. Excitingly, we found YRNA HY4 displays significant differential expression (p=0.025) between patients experiencing mild and severe disease. In agreement with recent reports identifying plasma YRNAs as indicators of influenza infection severity, our results strongly suggest that circulating HY4 levels represent a powerful prognostic indicator of likely SARS-CoV-2 patient infection outcome.
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Affiliation(s)
| | - Miles A. Hunt
- Biology, Howard University, Washington, Washington, D.C., United States
| | - Sunita S. Paudel
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
| | - Kevin N. Nguyen
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
| | - Haley A. Delcher
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
| | - Jeffrey D. DeMeis
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
| | - Justin T. Roberts
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
| | - Brian W. Fouty
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
- Internal Medicine, University of South Alabama, Mobile, Alabama, United States
| | - Jonathon P. Audia
- Microbiology & Immunology, University of South Alabama, Mobile, Alabama, United States
| | - Jin H. Kim
- Microbiology & Immunology, University of South Alabama, Mobile, Alabama, United States
| | - Glen M. Borchert
- Pharmacology, University of South Alabama, Mobile, Alabama, United States
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2
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Pavlova I, Iudin M, Surdina A, Severov V, Varizhuk A. G-Quadruplexes in Nuclear Biomolecular Condensates. Genes (Basel) 2023; 14:genes14051076. [PMID: 37239436 DOI: 10.3390/genes14051076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
G-quadruplexes (G4s) have long been implicated in the regulation of chromatin packaging and gene expression. These processes require or are accelerated by the separation of related proteins into liquid condensates on DNA/RNA matrices. While cytoplasmic G4s are acknowledged scaffolds of potentially pathogenic condensates, the possible contribution of G4s to phase transitions in the nucleus has only recently come to light. In this review, we summarize the growing evidence for the G4-dependent assembly of biomolecular condensates at telomeres and transcription initiation sites, as well as nucleoli, speckles, and paraspeckles. The limitations of the underlying assays and the remaining open questions are outlined. We also discuss the molecular basis for the apparent permissive role of G4s in the in vitro condensate assembly based on the interactome data. To highlight the prospects and risks of G4-targeting therapies with respect to the phase transitions, we also touch upon the reported effects of G4-stabilizing small molecules on nuclear biomolecular condensates.
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Affiliation(s)
- Iuliia Pavlova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Mikhail Iudin
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Anastasiya Surdina
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
| | - Vjacheslav Severov
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
| | - Anna Varizhuk
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine, 119435 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
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3
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Wang G, Vasquez KM. Dynamic alternative DNA structures in biology and disease. Nat Rev Genet 2023; 24:211-234. [PMID: 36316397 DOI: 10.1038/s41576-022-00539-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Repetitive elements in the human genome, once considered 'junk DNA', are now known to adopt more than a dozen alternative (that is, non-B) DNA structures, such as self-annealed hairpins, left-handed Z-DNA, three-stranded triplexes (H-DNA) or four-stranded guanine quadruplex structures (G4 DNA). These dynamic conformations can act as functional genomic elements involved in DNA replication and transcription, chromatin organization and genome stability. In addition, recent studies have revealed a role for these alternative structures in triggering error-generating DNA repair processes, thereby actively enabling genome plasticity. As a driving force for genetic variation, non-B DNA structures thus contribute to both disease aetiology and evolution.
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Affiliation(s)
- Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA.
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4
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G4-interacting proteins endangering genomic stability at G4 DNA-forming sites. Biochem Soc Trans 2023; 51:403-413. [PMID: 36629511 PMCID: PMC10018705 DOI: 10.1042/bst20221018] [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: 10/19/2022] [Revised: 12/09/2022] [Accepted: 01/03/2023] [Indexed: 01/12/2023]
Abstract
In guanine-rich DNA strands, base-base interactions among guanines allow the conformational shift from the B-form DNA to the non-canonical quadruplex or G4 structure. The functional significance of G4 DNA in vivo is largely dependent on the interaction with protein factors, many of which contain the arginine-glycine-glycine or RGG repeat and other consensus G4-binding motifs. These G4-interacting proteins can significantly modulate the effect of G4 DNA structure on genome maintenance, either preventing or aggravating G4-assoicated genome instability. While the role of helicases in resolving G4 DNA structure has been extensively discussed, identification and characterization of protein factors contributing to elevation in G4-associated genome instability has been relatively sparse. In this minireview, we will particularly highlight recent discoveries regarding how interaction between certain G4-binding proteins and G4 DNA could exacerbate genome instability potentiated by G4 DNA-forming sequences.
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5
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Makhoul M, Chawla HS, Wittkop B, Stahl A, Voss-Fels KP, Zetzsche H, Snowdon RJ, Obermeier C. Long-Amplicon Single-Molecule Sequencing Reveals Novel, Trait-Associated Variants of VERNALIZATION1 Homoeologs in Hexaploid Wheat. FRONTIERS IN PLANT SCIENCE 2022; 13:942461. [PMID: 36420025 PMCID: PMC9676936 DOI: 10.3389/fpls.2022.942461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/03/2022] [Indexed: 05/26/2023]
Abstract
The gene VERNALIZATION1 (VRN1) is a key controller of vernalization requirement in wheat. The genome of hexaploid wheat (Triticum aestivum) harbors three homoeologous VRN1 loci on chromosomes 5A, 5B, and 5D. Structural sequence variants including small and large deletions and insertions and single nucleotide polymorphisms (SNPs) in the three homoeologous VRN1 genes not only play an important role in the control of vernalization requirement, but also have been reported to be associated with other yield related traits of wheat. Here we used single-molecule sequencing of barcoded long-amplicons to assay the full-length sequences (∼13 kbp plus 700 bp from the promoter sequence) of the three homoeologous VRN1 genes in a panel of 192 predominantly European winter wheat cultivars. Long read sequences revealed previously undetected duplications, insertions and single-nucleotide polymorphisms in the three homoeologous VRN1 genes. All the polymorphisms were confirmed by Sanger sequencing. Sequence analysis showed the predominance of the winter alleles vrn-A1, vrn-B1, and vrn-D1 across the investigated cultivars. Associations of SNPs and structural variations within the three VRN1 genes with 20 economically relevant traits including yield, nodal root-angle index and quality related traits were evaluated at the levels of alleles, haplotypes, and copy number variants. Cultivars carrying structural variants within VRN1 genes showed lower grain yield, protein yield and biomass compared to those with intact genes. Cultivars carrying a single vrn-A1 copy and a unique haplotype with a high number of SNPs were found to have elevated grain yield, kernels per spike and kernels per m2 along with lower grain sedimentation values. In addition, we detected a novel SNP polymorphism within the G-quadruplex region of the promoter of vrn-A1 that was associated with deeper roots in winter wheat. Our findings show that multiplex, single-molecule long-amplicon sequencing is a useful tool for detecting variants in target genes within large plant populations, and can be used to simultaneously assay sequence variants among target multiple gene homoeologs in polyploid crops. Numerous novel VRN1 haplotypes and alleles were identified that showed significantly associations to economically important traits. These polymorphisms were converted into PCR or KASP assays for use in marker-assisted breeding.
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Affiliation(s)
- Manar Makhoul
- Department of Plant Breeding, Justus Liebig University Giessen, Giessen, Germany
| | - Harmeet S. Chawla
- Department of Plant Breeding, Justus Liebig University Giessen, Giessen, Germany
- Department of Plant Sciences, Crop Development Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Benjamin Wittkop
- Department of Plant Breeding, Justus Liebig University Giessen, Giessen, Germany
| | - Andreas Stahl
- Institute for Resistance Research and Stress Tolerance, Julius Kühn Institute, Quedlinburg, Germany
| | - Kai Peter Voss-Fels
- Institute for Grapevine Breeding, Hochschule Geisenheim University, Geisenheim, Germany
| | - Holger Zetzsche
- Institute for Resistance Research and Stress Tolerance, Julius Kühn Institute, Quedlinburg, Germany
| | - Rod J. Snowdon
- Department of Plant Breeding, Justus Liebig University Giessen, Giessen, Germany
| | - Christian Obermeier
- Department of Plant Breeding, Justus Liebig University Giessen, Giessen, Germany
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Singh M, Gupta R, Comez L, Paciaroni A, Rani R, Kumar V. BCL2 G quadruplex-binding small molecules: Current status and prospects for the development of next-generation anticancer therapeutics. Drug Discov Today 2022; 27:2551-2561. [PMID: 35709931 DOI: 10.1016/j.drudis.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 11/03/2022]
Abstract
B cell lymphoma 2 (BCL2) overexpression in a range of human tumors is often related to chemotherapy resistance and poor prognosis. GC-rich regions upstream of the P1 promoter in human BCL2 can form G-quadruplex (G4) structures through the stacking of four Hoogsteen-paired guanine bases. Stabilizing the G4 fold implies the inhibition of BCL2 expression and, thus, small molecules that selectively bind to the G4 are promising anticancer candidates. In this review, we discuss the structural aspects, binding affinity, selectivity, and biological activity of well-characterized BCL2 G4 binding ligands in vitro and in vivo. We also explore future directions in the research and development of G4-based anticancer therapeutics.
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Affiliation(s)
- Mamta Singh
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University, Noida, UP, 201303, India
| | - Rajat Gupta
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University, Noida, UP, 201303, India
| | - Lucia Comez
- IOM-CNR National Research Council, Via Pascoli, Perugia I-06123, Italy
| | - Alessandro Paciaroni
- Department of Physics and Geology, University of Perugia, via Pascoli, 06123, Italy
| | - Reshma Rani
- Drug Discovery Unit, Jubilant Biosys Ltd, Sector 58, Noida, UP 201301, India.
| | - Vinit Kumar
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University, Noida, UP, 201303, India.
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7
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Iwasaki Y, Ookuro Y, Iida K, Nagasawa K, Yoshida W. Destabilization of DNA and RNA G-quadruplex structures formed by GGA repeat due to N 6-methyladenine modification. Biochem Biophys Res Commun 2022; 597:134-139. [PMID: 35144176 DOI: 10.1016/j.bbrc.2022.01.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 01/30/2022] [Indexed: 11/22/2022]
Abstract
N6-methyladenine (m6A) is the most abundant RNA modification in eukaryotic RNA. Further, m6A has been identified in the genomic DNA of both eukaryotes and prokaryotes. The G-quadruplex (G4) structure is a non-canonical nucleic acid structure formed by the stacking of G:G:G:G tetrads. In this study, we evaluated the effect of m6A modifications on G4 structures formed by GGA repeat oligonucleotides, d(GGA)8, d(GGA)4, and r(GGA)4. The d(GGA)8 forms an intramolecular tetrad:heptad:heptad:tetrad G4 structure, while d(GGA)4 forms a dimerized intermolecular tetrad:heptad:heptad:tetrad G4 structure. r(GGA)4 forms a dimerized intermolecular tetrad:hexad:hexad:tetrad G4 structure. Circular dichroism melting analysis demonstrated that (1) m6A modifications destabilized the G4 structure formed by d(GGA)8, (2) m6A modification at A3 disrupted the G4 structure formed by d(GGA)4, and (3) m6A modification at A3 destabilized the G4 structure formed by r(GGA)4. m6A modifications may be involved in controlling G4 structure formation to regulate biological functions.
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Affiliation(s)
- Yuka Iwasaki
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, 192-0982, Japan
| | - Yurino Ookuro
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, 192-0982, Japan
| | - Keisuke Iida
- Department of Chemistry, Chiba University, 1-33 Yayoi, Inage, Chiba, 263-8522, Japan
| | - Kazuo Nagasawa
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo, 184-8588, Japan
| | - Wataru Yoshida
- Graduate School of Bionics, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, 192-0982, Japan; School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, 192-0982, Japan.
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8
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Lyu J, Shao R, Kwong Yung PY, Elsässer SJ. Genome-wide mapping of G-quadruplex structures with CUT&Tag. Nucleic Acids Res 2021; 50:e13. [PMID: 34792172 PMCID: PMC8860588 DOI: 10.1093/nar/gkab1073] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 10/01/2021] [Accepted: 10/20/2021] [Indexed: 12/22/2022] Open
Abstract
Single-stranded genomic DNA can fold into G-quadruplex (G4) structures or form DNA:RNA hybrids (R loops). Recent evidence suggests that such non-canonical DNA structures affect gene expression, DNA methylation, replication fork progression and genome stability. When and how G4 structures form and are resolved remains unclear. Here we report the use of Cleavage Under Targets and Tagmentation (CUT&Tag) for mapping native G4 in mammalian cell lines at high resolution and low background. Mild native conditions used for the procedure retain more G4 structures and provide a higher signal-to-noise ratio than ChIP-based methods. We determine the G4 landscape of mouse embryonic stem cells (ESC), observing widespread G4 formation at active promoters, active and poised enhancers. We discover that the presence of G4 motifs and G4 structures distinguishes active and primed enhancers in mouse ESCs. Upon differentiation to neural progenitor cells (NPC), enhancer G4s are lost. Further, performing R-loop CUT&Tag, we demonstrate the genome-wide co-occurrence of single-stranded DNA, G4s and R loops at promoters and enhancers. We confirm that G4 structures exist independent of ongoing transcription, suggesting an intricate relationship between transcription and non-canonical DNA structures.
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Affiliation(s)
- Jing Lyu
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Tomtebodavägen 23, 17165 Stockholm, Sweden.,Ming Wai Lau Centre for Reparative Medicine, Stockholm node, Karolinska Institutet, Solnavägen 9, 17165 Stockholm, Sweden
| | - Rui Shao
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Tomtebodavägen 23, 17165 Stockholm, Sweden.,Ming Wai Lau Centre for Reparative Medicine, Stockholm node, Karolinska Institutet, Solnavägen 9, 17165 Stockholm, Sweden
| | - Philip Yuk Kwong Yung
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Tomtebodavägen 23, 17165 Stockholm, Sweden.,Ming Wai Lau Centre for Reparative Medicine, Stockholm node, Karolinska Institutet, Solnavägen 9, 17165 Stockholm, Sweden
| | - Simon J Elsässer
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Tomtebodavägen 23, 17165 Stockholm, Sweden.,Ming Wai Lau Centre for Reparative Medicine, Stockholm node, Karolinska Institutet, Solnavägen 9, 17165 Stockholm, Sweden
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9
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Marilovtseva EV, Studitsky VM. Guanine Quadruplexes in Cell Nucleus Metabolism. Mol Biol 2021. [DOI: 10.1134/s0026893321040075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Robinson J, Raguseo F, Nuccio SP, Liano D, Di Antonio M. DNA G-quadruplex structures: more than simple roadblocks to transcription? Nucleic Acids Res 2021; 49:8419-8431. [PMID: 34255847 PMCID: PMC8421137 DOI: 10.1093/nar/gkab609] [Citation(s) in RCA: 113] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 12/12/2022] Open
Abstract
It has been >20 years since the formation of G-quadruplex (G4) secondary structures in gene promoters was first linked to the regulation of gene expression. Since then, the development of small molecules to selectively target G4s and their cellular application have contributed to an improved understanding of how G4s regulate transcription. One model that arose from this work placed these non-canonical DNA structures as repressors of transcription by preventing polymerase processivity. Although a considerable number of studies have recently provided sufficient evidence to reconsider this simplistic model, there is still a misrepresentation of G4s as transcriptional roadblocks. In this review, we will challenge this model depicting G4s as simple 'off switches' for gene expression by articulating how their formation has the potential to alter gene expression at many different levels, acting as a key regulatory element perturbing the nature of epigenetic marks and chromatin architecture.
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Affiliation(s)
- Jenna Robinson
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Federica Raguseo
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Sabrina Pia Nuccio
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Denise Liano
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Marco Di Antonio
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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11
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Guiblet WM, DeGiorgio M, Cheng X, Chiaromonte F, Eckert KA, Huang YF, Makova KD. Selection and thermostability suggest G-quadruplexes are novel functional elements of the human genome. Genome Res 2021; 31:1136-1149. [PMID: 34187812 PMCID: PMC8256861 DOI: 10.1101/gr.269589.120] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 05/24/2021] [Indexed: 12/11/2022]
Abstract
Approximately 1% of the human genome has the ability to fold into G-quadruplexes (G4s)-noncanonical strand-specific DNA structures forming at G-rich motifs. G4s regulate several key cellular processes (e.g., transcription) and have been hypothesized to participate in others (e.g., firing of replication origins). Moreover, G4s differ in their thermostability, and this may affect their function. Yet, G4s may also hinder replication, transcription, and translation and may increase genome instability and mutation rates. Therefore, depending on their genomic location, thermostability, and functionality, G4 loci might evolve under different selective pressures, which has never been investigated. Here we conducted the first genome-wide analysis of G4 distribution, thermostability, and selection. We found an overrepresentation, high thermostability, and purifying selection for G4s within genic components in which they are expected to be functional-promoters, CpG islands, and 5' and 3' UTRs. A similar pattern was observed for G4s within replication origins, enhancers, eQTLs, and TAD boundary regions, strongly suggesting their functionality. In contrast, G4s on the nontranscribed strand of exons were underrepresented, were unstable, and evolved neutrally. In general, G4s on the nontranscribed strand of genic components had lower density and were less stable than those on the transcribed strand, suggesting that the former are avoided at the RNA level. Across the genome, purifying selection was stronger at stable G4s. Our results suggest that purifying selection preserves the sequences of functional G4s, whereas nonfunctional G4s are too costly to be tolerated in the genome. Thus, G4s are emerging as fundamental, functional genomic elements.
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Affiliation(s)
- Wilfried M Guiblet
- Bioinformatics and Genomics Graduate Program, Penn State University, University Park, Pennsylvania 16802, USA
| | - Michael DeGiorgio
- Department of Computer and Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, Florida 33431, USA
| | - Xiaoheng Cheng
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
| | - Francesca Chiaromonte
- Department of Statistics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for Medical Genomics, Penn State University, University Park and Hershey, Pennsylvania 16802, USA
- Sant'Anna School of Advanced Studies, 56127 Pisa, Italy
| | - Kristin A Eckert
- Center for Medical Genomics, Penn State University, University Park and Hershey, Pennsylvania 16802, USA
- Department of Pathology, Penn State University, College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Yi-Fei Huang
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
- Center for Medical Genomics, Penn State University, University Park and Hershey, Pennsylvania 16802, USA
| | - Kateryna D Makova
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
- Center for Medical Genomics, Penn State University, University Park and Hershey, Pennsylvania 16802, USA
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12
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Singh S, Berroyer A, Kim M, Kim N. Yeast Nucleolin Nsr1 Impedes Replication and Elevates Genome Instability at an Actively Transcribed Guanine-Rich G4 DNA-Forming Sequence. Genetics 2020; 216:1023-1037. [PMID: 33106247 PMCID: PMC7768239 DOI: 10.1534/genetics.120.303736] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/21/2020] [Indexed: 12/01/2022] Open
Abstract
A significant increase in genome instability is associated with the conformational shift of a guanine-run-containing DNA strand into the four-stranded G-quadruplex (G4) DNA. The mechanism underlying the recombination and genome rearrangements following the formation of G4 DNA in vivo has been difficult to elucidate but has become better clarified by the identification and functional characterization of several key G4 DNA-binding proteins. Mammalian nucleolin (NCL) is a highly specific G4 DNA-binding protein with a well-defined role in the transcriptional regulation of genes with associated G4 DNA-forming sequence motifs at their promoters. The consequence of the in vivo interaction between G4 DNA and nucleolin in respect to the genome instability has not been previously investigated. We show here that the yeast nucleolin Nsr1 is enriched at a G4 DNA-forming sequence in vivo and is a major factor in inducing the genome instability associated with the cotranscriptionally formed G4 DNA in the yeast genome. We also show that Nsr1 results in impeding replication past such a G4 DNA-forming sequence. The G4-associated genome instability and the G4 DNA-binding in vivo require the arginine-glycine-glycine (RGG) repeats located at the C-terminus of the Nsr1 protein. Nsr1 with the deletion of RGG domain supports normal cell growth and is sufficient for its pre-rRNA processing function. However, the truncation of the RGG domain of Nsr1 significantly weakens its interaction with G4 DNA in vivo and restores unhindered replication, overall resulting in a sharp reduction in the genome instability associated with a guanine-rich G4 DNA-forming sequence. Our data suggest that the interaction between Nsr1 with the intact RGG repeats and G4 DNA impairs genome stability by precluding the access of G4-resolving proteins and impeding replication.
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Affiliation(s)
- Shivani Singh
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Alexandra Berroyer
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas 77030
- University of Texas (UT) Health MD Anderson Cancer Center Graduate School of Biomedical Sciences, Houston, Texas 77030
| | - Minseon Kim
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas 77030
- University of Texas (UT) Health MD Anderson Cancer Center Graduate School of Biomedical Sciences, Houston, Texas 77030
| | - Nayun Kim
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, Houston, Texas 77030
- University of Texas (UT) Health MD Anderson Cancer Center Graduate School of Biomedical Sciences, Houston, Texas 77030
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