1
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Hisey JA, Radchenko EA, Mandel NH, McGinty R, Matos-Rodrigues G, Rastokina A, Masnovo C, Ceschi S, Hernandez A, Nussenzweig A, Mirkin S. Pathogenic CANVAS (AAGGG)n repeats stall DNA replication due to the formation of alternative DNA structures. Nucleic Acids Res 2024; 52:4361-4374. [PMID: 38381906 PMCID: PMC11077069 DOI: 10.1093/nar/gkae124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 02/06/2024] [Accepted: 02/08/2024] [Indexed: 02/23/2024] Open
Abstract
CANVAS is a recently characterized repeat expansion disease, most commonly caused by homozygous expansions of an intronic (A2G3)n repeat in the RFC1 gene. There are a multitude of repeat motifs found in the human population at this locus, some of which are pathogenic and others benign. In this study, we conducted structure-functional analyses of the pathogenic (A2G3)n and nonpathogenic (A4G)n repeats. We found that the pathogenic, but not the nonpathogenic, repeat presents a potent, orientation-dependent impediment to DNA polymerization in vitro. The pattern of the polymerization blockage is consistent with triplex or quadruplex formation in the presence of magnesium or potassium ions, respectively. Chemical probing of both repeats in vitro reveals triplex H-DNA formation by only the pathogenic repeat. Consistently, bioinformatic analysis of S1-END-seq data from human cell lines shows preferential H-DNA formation genome-wide by (A2G3)n motifs over (A4G)n motifs. Finally, the pathogenic, but not the nonpathogenic, repeat stalls replication fork progression in yeast and human cells. We hypothesize that the CANVAS-causing (A2G3)n repeat represents a challenge to genome stability by folding into alternative DNA structures that stall DNA replication.
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Affiliation(s)
- Julia A Hisey
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | | | | | - Ryan J McGinty
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115, USA
| | | | | | - Chiara Masnovo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Silvia Ceschi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
| | | | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute NIH, Bethesda, MD20892, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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2
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Goldberg ME, Noyes MD, Eichler EE, Quinlan AR, Harris K. Effects of parental age and polymer composition on short tandem repeat de novo mutation rates. Genetics 2024; 226:iyae013. [PMID: 38298127 PMCID: PMC10990422 DOI: 10.1093/genetics/iyae013] [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: 08/11/2023] [Revised: 08/11/2023] [Accepted: 01/05/2024] [Indexed: 02/02/2024] Open
Abstract
Short tandem repeats (STRs) are hotspots of genomic variability in the human germline because of their high mutation rates, which have long been attributed largely to polymerase slippage during DNA replication. This model suggests that STR mutation rates should scale linearly with a father's age, as progenitor cells continually divide after puberty. In contrast, it suggests that STR mutation rates should not scale with a mother's age at her child's conception, since oocytes spend a mother's reproductive years arrested in meiosis II and undergo a fixed number of cell divisions that are independent of the age at ovulation. Yet, mirroring recent findings, we find that STR mutation rates covary with paternal and maternal age, implying that some STR mutations are caused by DNA damage in quiescent cells rather than polymerase slippage in replicating progenitor cells. These results echo the recent finding that DNA damage in oocytes is a significant source of de novo single nucleotide variants and corroborate evidence of STR expansion in postmitotic cells. However, we find that the maternal age effect is not confined to known hotspots of oocyte mutagenesis, nor are postzygotic mutations likely to contribute significantly. STR nucleotide composition demonstrates divergent effects on de novo mutation (DNM) rates between sexes. Unlike the paternal lineage, maternally derived DNMs at A/T STRs display a significantly greater association with maternal age than DNMs at G/C-containing STRs. These observations may suggest the mechanism and developmental timing of certain STR mutations and contradict prior attribution of replication slippage as the primary mechanism of STR mutagenesis.
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Affiliation(s)
- Michael E Goldberg
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Departments of Human Genetics and Biomedical Informatics, University of Utah, Salt Lake City, UT 84112, USA
| | - Michelle D Noyes
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Aaron R Quinlan
- Departments of Human Genetics and Biomedical Informatics, University of Utah, Salt Lake City, UT 84112, USA
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
- Computational Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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3
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Goldberg ME, Noyes MD, Eichler EE, Quinlan AR, Harris K. Effects of parental age and polymer composition on short tandem repeat de novo mutation rates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573131. [PMID: 38187618 PMCID: PMC10769404 DOI: 10.1101/2023.12.22.573131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Short tandem repeats (STRs) are hotspots of genomic variability in the human germline because of their high mutation rates, which have long been attributed largely to polymerase slippage during DNA replication. This model suggests that STR mutation rates should scale linearly with a father's age, as progenitor cells continually divide after puberty. In contrast, it suggests that STR mutation rates should not scale with a mother's age at her child's conception, since oocytes spend a mother's reproductive years arrested in meiosis II and undergo a fixed number of cell divisions that are independent of the age at ovulation. Yet, mirroring recent findings, we find that STR mutation rates covary with paternal and maternal age, implying that some STR mutations are caused by DNA damage in quiescent cells rather than the classical mechanism of polymerase slippage in replicating progenitor cells. These results also echo the recent finding that DNA damage in quiescent oocytes is a significant source of de novo SNVs and corroborate evidence of STR expansion in postmitotic cells. However, we find that the maternal age effect is not confined to previously discovered hotspots of oocyte mutagenesis, nor are post-zygotic mutations likely to contribute significantly. STR nucleotide composition demonstrates divergent effects on DNM rates between sexes. Unlike the paternal lineage, maternally derived DNMs at A/T STRs display a significantly greater association with maternal age than DNMs at GC-containing STRs. These observations may suggest the mechanism and developmental timing of certain STR mutations and are especially surprising considering the prior belief in replication slippage as the dominant mechanism of STR mutagenesis.
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Affiliation(s)
- Michael E. Goldberg
- Department of Genome Sciences, University of Washington, 3720 15 Ave NE, Seattle, WA, 98195
- Departments of Human Genetics and Biomedical Informatics, University of Utah, 15 S 2030 E, Salt Lake City, UT, 84112
| | - Michelle D. Noyes
- Department of Genome Sciences, University of Washington, 3720 15 Ave NE, Seattle, WA, 98195
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington, 3720 15 Ave NE, Seattle, WA, 98195
- Howard Hughes Medical Institute, 3720 15 Ave NE, University of Washington, Seattle, WA, 98195
| | - Aaron R. Quinlan
- Departments of Human Genetics and Biomedical Informatics, University of Utah, 15 S 2030 E, Salt Lake City, UT, 84112
- These authors contributed equally to this work
| | - Kelley Harris
- Department of Genome Sciences, University of Washington, 3720 15 Ave NE, Seattle, WA, 98195
- Computational Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, Seattle, WA, 98109
- These authors contributed equally to this work
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Lorenzatti A, Piga EJ, Gismondi M, Binolfi A, Margarit E, Calcaterra N, Armas P. Genetic variations in G-quadruplex forming sequences affect the transcription of human disease-related genes. Nucleic Acids Res 2023; 51:12124-12139. [PMID: 37930868 PMCID: PMC10711447 DOI: 10.1093/nar/gkad948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 11/08/2023] Open
Abstract
Guanine-rich DNA strands can fold into non-canonical four-stranded secondary structures named G-quadruplexes (G4s). G4s folded in proximal promoter regions (PPR) are associated either with positive or negative transcriptional regulation. Given that single nucleotide variants (SNVs) affecting G4 folding (G4-Vars) may alter gene transcription, and that SNVs are associated with the human diseases' onset, we undertook a novel comprehensive study of the G4-Vars genome-wide (G4-variome) to find disease-associated G4-Vars located into PPRs. We developed a bioinformatics strategy to find disease-related SNVs located into PPRs simultaneously overlapping with putative G4-forming sequences (PQSs). We studied five G4-Vars disturbing in vitro the folding and stability of the G4s located into PPRs, which had been formerly associated with sporadic Alzheimer's disease (GRIN2B), a severe familiar coagulopathy (F7), atopic dermatitis (CSF2), myocardial infarction (SIRT1) and deafness (LHFPL5). Results obtained in cultured cells for these five G4-Vars suggest that the changes in the G4s affect the transcription, potentially contributing to the development of the mentioned diseases. Collectively, data reinforce the general idea that G4-Vars may impact on the different susceptibilities to human genetic diseases' onset, and could be novel targets for diagnosis and drug design in precision medicine.
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Affiliation(s)
- Agustín Lorenzatti
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, Rosario S2000EZP, Santa Fe, Argentina
| | - Ernesto J Piga
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, Rosario S2000EZP, Santa Fe, Argentina
| | - Mauro Gismondi
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 531, Rosario, Santa Fe, Argentina
| | - Andrés Binolfi
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, Rosario S2000EZP, Santa Fe, Argentina
- Plataforma Argentina de Biología Estructural y Metabolómica (PLABEM), Ocampo y Esmeralda, Rosario S200EZP, Santa Fe, Argentina
| | - Ezequiel Margarit
- Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Suipacha 531, Rosario, Santa Fe, Argentina
| | - Nora B Calcaterra
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, Rosario S2000EZP, Santa Fe, Argentina
| | - Pablo Armas
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Ocampo y Esmeralda, Rosario S2000EZP, Santa Fe, Argentina
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Matos-Rodrigues G, Hisey JA, Nussenzweig A, Mirkin SM. Detection of alternative DNA structures and its implications for human disease. Mol Cell 2023; 83:3622-3641. [PMID: 37863029 DOI: 10.1016/j.molcel.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 10/22/2023]
Abstract
Around 3% of the genome consists of simple DNA repeats that are prone to forming alternative (non-B) DNA structures, such as hairpins, cruciforms, triplexes (H-DNA), four-stranded guanine quadruplexes (G4-DNA), and others, as well as composite RNA:DNA structures (e.g., R-loops, G-loops, and H-loops). These DNA structures are dynamic and favored by the unwinding of duplex DNA. For many years, the association of alternative DNA structures with genome function was limited by the lack of methods to detect them in vivo. Here, we review the recent advancements in the field and present state-of-the-art technologies and methods to study alternative DNA structures. We discuss the limitations of these methods as well as how they are beginning to provide insights into causal relationships between alternative DNA structures, genome function and stability, and human disease.
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Affiliation(s)
| | - Julia A Hisey
- Department of Biology, Tufts University, Medford, MA, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA.
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Herbert A. Flipons and small RNAs accentuate the asymmetries of pervasive transcription by the reset and sequence-specific microcoding of promoter conformation. J Biol Chem 2023; 299:105140. [PMID: 37544644 PMCID: PMC10474125 DOI: 10.1016/j.jbc.2023.105140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
The role of alternate DNA conformations such as Z-DNA in the regulation of transcription is currently underappreciated. These structures are encoded by sequences called flipons, many of which are enriched in promoter and enhancer regions. Through a change in their conformation, flipons provide a tunable mechanism to mechanically reset promoters for the next round of transcription. They act as actuators that capture and release energy to ensure that the turnover of the proteins at promoters is optimized to cell state. Likewise, the single-stranded DNA formed as flipons cycle facilitates the docking of RNAs that are able to microcode promoter conformations and canalize the pervasive transcription commonly observed in metazoan genomes. The strand-specific nature of the interaction between RNA and DNA likely accounts for the known asymmetry of epigenetic marks present on the histone tetramers that pair to form nucleosomes. The role of these supercoil-dependent processes in promoter choice and transcriptional interference is reviewed. The evolutionary implications are examined: the resilience and canalization of flipon-dependent gene regulation is contrasted with the rapid adaptation enabled by the spread of flipon repeats throughout the genome. Overall, the current findings underscore the important role of flipons in modulating the readout of genetic information and how little we know about their biology.
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Affiliation(s)
- Alan Herbert
- Discovery Division, InsideOutBio, Charlestown, Massachusetts, USA.
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7
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Hisey JA, Radchenko EA, Ceschi S, Rastokina A, Mandel NH, McGinty RJ, Matos-Rodrigues G, Hernandez A, Nussenzweig A, Mirkin SM. Pathogenic CANVAS (AAGGG) n repeats stall DNA replication due to the formation of alternative DNA structures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550509. [PMID: 37546920 PMCID: PMC10402041 DOI: 10.1101/2023.07.25.550509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
CANVAS is a recently characterized repeat expansion disease, most commonly caused by homozygous expansions of an intronic (A2G3)n repeat in the RFC1 gene. There are a multitude of repeat motifs found in the human population at this locus, some of which are pathogenic and others benign. In this study, we conducted structure-functional analyses of the main pathogenic (A2G3)n and the main nonpathogenic (A4G)n repeats. We found that the pathogenic, but not the nonpathogenic, repeat presents a potent, orientation-dependent impediment to DNA polymerization in vitro. The pattern of the polymerization blockage is consistent with triplex or quadruplex formation in the presence of magnesium or potassium ions, respectively. Chemical probing of both repeats in supercoiled DNA reveals triplex H-DNA formation by the pathogenic repeat. Consistently, bioinformatic analysis of the S1-END-seq data from human cell lines shows preferential H-DNA formation genome-wide by (A2G3)n motifs over (A4G)n motifs in vivo. Finally, the pathogenic, but not the non-pathogenic, repeat stalls replication fork progression in yeast and human cells. We hypothesize that CANVAS-causing (A2G3)n repeat represents a challenge to genome stability by folding into alternative DNA structures that stall DNA replication.
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Affiliation(s)
- Julia A. Hisey
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | | | - Silvia Ceschi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova 35131, Italy
| | | | | | - Ryan J. McGinty
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute NIH, Bethesda, MD, USA
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