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Bartas M, Brázda V, Pečinka P. Special Issue "Bioinformatics of Unusual DNA and RNA Structures". Int J Mol Sci 2024; 25:5226. [PMID: 38791265 PMCID: PMC11121459 DOI: 10.3390/ijms25105226] [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: 04/18/2024] [Revised: 04/29/2024] [Accepted: 05/06/2024] [Indexed: 05/26/2024] Open
Abstract
Nucleic acids are not only static carriers of genetic information but also play vital roles in controlling cellular lifecycles through their fascinating structural diversity [...].
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Affiliation(s)
- Martin Bartas
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic;
| | - Václav Brázda
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 00 Brno, Czech Republic;
| | - Petr Pečinka
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic;
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2
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Duardo RC, Guerra F, Pepe S, Capranico G. Non-B DNA structures as a booster of genome instability. Biochimie 2023; 214:176-192. [PMID: 37429410 DOI: 10.1016/j.biochi.2023.07.002] [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: 03/29/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Non-canonical secondary structures (NCSs) are alternative nucleic acid structures that differ from the canonical B-DNA conformation. NCSs often occur in repetitive DNA sequences and can adopt different conformations depending on the sequence. The majority of these structures form in the context of physiological processes, such as transcription-associated R-loops, G4s, as well as hairpins and slipped-strand DNA, whose formation can be dependent on DNA replication. It is therefore not surprising that NCSs play important roles in the regulation of key biological processes. In the last years, increasing published data have supported their biological role thanks to genome-wide studies and the development of bioinformatic prediction tools. Data have also highlighted the pathological role of these secondary structures. Indeed, the alteration or stabilization of NCSs can cause the impairment of transcription and DNA replication, modification in chromatin structure and DNA damage. These events lead to a wide range of recombination events, deletions, mutations and chromosomal aberrations, well-known hallmarks of genome instability which are strongly associated with human diseases. In this review, we summarize molecular processes through which NCSs trigger genome instability, with a focus on G-quadruplex, i-motif, R-loop, Z-DNA, hairpin, cruciform and multi-stranded structures known as triplexes.
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Affiliation(s)
- Renée C Duardo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Federico Guerra
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Simona Pepe
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy.
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3
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Cui X, Li Y, Xu H, Sun Y, Jiang S, Li W. Characteristics of Hepatitis B virus integration and mechanism of inducing chromosome translocation. NPJ Genom Med 2023; 8:11. [PMID: 37268616 DOI: 10.1038/s41525-023-00355-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 05/23/2023] [Indexed: 06/04/2023] Open
Abstract
Hepatitis B virus (HBV) integration is closely associated with the onset and progression of tumors. This study utilized the DNA of 27 liver cancer samples for high-throughput Viral Integration Detection (HIVID), with the overarching goal of detecting HBV integration. KEGG pathway analysis of breakpoints was performed using the ClusterProfiler software. The breakpoints were annotated using the latest ANNOVAR software. We identified 775 integration sites and detected two new hotspot genes for virus integration, N4BP1 and WASHP, along with 331 new genes. Furthermore, we conducted a comprehensive analysis to determine the critical impact pathways of virus integration by combining our findings with the results of three major global studies on HBV integration. Meanwhile, we found common characteristics of virus integration hotspots among different ethnic groups. To specify the direct impact of virus integration on genomic instability, we explained the causes of inversion and the frequent occurrence of translocation due to HBV integration. This study detected a series of hotspot integration genes and specified common characteristics of critical hotspot integration genes. These hotspot genes are universal across different ethnic groups, providing an effective target for better research on the pathogenic mechanism. We also demonstrated more comprehensive key pathways affected by HBV integration and elucidated the mechanism for inversion and frequent translocation events due to virus integration. Apart from the great significance of the rule of HBV integration, the current study also provides valuable insights into the mechanism of virus integration.
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Affiliation(s)
- Xiaofang Cui
- Jining Medical University, Jining, Shandong, China
- School of Biological Science, Jining Medical University, Rizhao, Shandong, China
| | - Yiyan Li
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Hanshi Xu
- Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yuhui Sun
- BGI-Shenzhen, 518083, Shenzhen, China
| | - Shulong Jiang
- Clinical Medical Laboratory Center, Jining First People's Hospital, Shandong First Medical University, Jining, China.
| | - Weiyang Li
- Jining Medical University, Jining, Shandong, China.
- School of Biological Science, Jining Medical University, Rizhao, Shandong, China.
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4
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Bowater RP, Bohálová N, Brázda V. Interaction of Proteins with Inverted Repeats and Cruciform Structures in Nucleic Acids. Int J Mol Sci 2022; 23:ijms23116171. [PMID: 35682854 PMCID: PMC9180970 DOI: 10.3390/ijms23116171] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/26/2022] [Accepted: 05/30/2022] [Indexed: 01/27/2023] Open
Abstract
Cruciforms occur when inverted repeat sequences in double-stranded DNA adopt intra-strand hairpins on opposing strands. Biophysical and molecular studies of these structures confirm their characterization as four-way junctions and have demonstrated that several factors influence their stability, including overall chromatin structure and DNA supercoiling. Here, we review our understanding of processes that influence the formation and stability of cruciforms in genomes, covering the range of sequences shown to have biological significance. It is challenging to accurately sequence repetitive DNA sequences, but recent advances in sequencing methods have deepened understanding about the amounts of inverted repeats in genomes from all forms of life. We highlight that, in the majority of genomes, inverted repeats are present in higher numbers than is expected from a random occurrence. It is, therefore, becoming clear that inverted repeats play important roles in regulating many aspects of DNA metabolism, including replication, gene expression, and recombination. Cruciforms are targets for many architectural and regulatory proteins, including topoisomerases, p53, Rif1, and others. Notably, some of these proteins can induce the formation of cruciform structures when they bind to DNA. Inverted repeat sequences also influence the evolution of genomes, and growing evidence highlights their significance in several human diseases, suggesting that the inverted repeat sequences and/or DNA cruciforms could be useful therapeutic targets in some cases.
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Affiliation(s)
- Richard P. Bowater
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK;
| | - Natália Bohálová
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics of the Czech Academy of Sciences, 61265 Brno, Czech Republic;
- Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Václav Brázda
- Department of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics of the Czech Academy of Sciences, 61265 Brno, Czech Republic;
- Correspondence:
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5
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Rekvig OP. The Anti-DNA Antibodies: Their Specificities for Unique DNA Structures and Their Unresolved Clinical Impact-A System Criticism and a Hypothesis. Front Immunol 2022; 12:808008. [PMID: 35087528 PMCID: PMC8786728 DOI: 10.3389/fimmu.2021.808008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/14/2021] [Indexed: 12/12/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is diagnosed and classified by criteria, or by experience, intuition and traditions, and not by scientifically well-defined etiology(ies) or pathogenicity(ies). One central criterion and diagnostic factor is founded on theoretical and analytical approaches based on our imperfect definition of the term “The anti-dsDNA antibody”. “The anti-dsDNA antibody” holds an archaic position in SLE as a unique classification criterium and pathogenic factor. In a wider sense, antibodies to unique transcriptionally active or silent DNA structures and chromatin components may have individual and profound nephritogenic impact although not considered yet – not in theoretical nor in descriptive or experimental contexts. This hypothesis is contemplated here. In this analysis, our state-of-the-art conception of these antibodies is probed and found too deficient with respect to their origin, structural DNA specificities and clinical/pathogenic impact. Discoveries of DNA structures and functions started with Miescher’s Nuclein (1871), via Chargaff, Franklin, Watson and Crick, and continues today. The discoveries have left us with a DNA helix that presents distinct structures expressing unique operations of DNA. All structures are proven immunogenic! Unique autoimmune antibodies are described against e.g. ssDNA, elongated B DNA, bent B DNA, Z DNA, cruciform DNA, or individual components of chromatin. In light of the massive scientific interest in anti-DNA antibodies over decades, it is an unexpected observation that the spectrum of DNA structures has been known for decades without being implemented in clinical immunology. This leads consequently to a critical analysis of historical and contemporary evidence-based data and of ignored and one-dimensional contexts and hypotheses: i.e. “one antibody - one disease”. In this study radical viewpoints on the impact of DNA and chromatin immunity/autoimmunity are considered and discussed in context of the pathogenesis of lupus nephritis.
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Affiliation(s)
- Ole Petter Rekvig
- Section of Autoimmunity, Fürst Medical Laboratory, Oslo, Norway.,Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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6
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Smirnov A, Battulin N. Concatenation of Transgenic DNA: Random or Orchestrated? Genes (Basel) 2021; 12:genes12121969. [PMID: 34946918 PMCID: PMC8701086 DOI: 10.3390/genes12121969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 12/18/2022] Open
Abstract
Generation of transgenic organisms by pronuclear microinjection has become a routine procedure. However, while the process of DNA integration in the genome is well understood, we still do not know much about the recombination between transgene molecules that happens in the first moments after DNA injection. Most of the time, injected molecules are joined together in head-to-tail tandem repeats-the so-called concatemers. In this review, we focused on the possible concatenation mechanisms and how they could be studied with genetic reporters tracking individual copies in concatemers. We also discuss various features of concatemers, including palindromic junctions and repeat-induced gene silencing (RIGS). Finally, we speculate how cooperation of DNA repair pathways creates a multicopy concatenated insert.
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Affiliation(s)
- Alexander Smirnov
- Laboratory of Developmental Genetics, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia;
| | - Nariman Battulin
- Laboratory of Developmental Genetics, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia;
- Institute of Genetic Technologies, Novosibirsk State University, 630090 Novosibirsk, Russia
- Correspondence:
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7
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Javadekar SM, Nilavar NM, Paranjape A, Das K, Raghavan SC. Characterization of G-quadruplex antibody reveals differential specificity for G4 DNA forms. DNA Res 2021; 27:5934508. [PMID: 33084858 PMCID: PMC7711166 DOI: 10.1093/dnares/dsaa024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022] Open
Abstract
Accumulating evidence suggests that human genome can fold into non-B DNA structures, when appropriate sequence and favourable conditions are present. Among these, G-quadruplexes (G4-DNA) are associated with gene regulation, chromosome fragility and telomere maintenance. Although several techniques are used in detecting such structures in vitro, understanding their intracellular existence has been challenging. Recently, an antibody, BG4, was described to study G4 structures within cells. Here, we characterize BG4 for its affinity towards G4-DNA, using several biochemical and biophysical tools. BG4 bound to G-rich DNA derived from multiple genes that form G-quadruplexes, unlike complementary C-rich or random sequences. BLI studies revealed robust binding affinity (Kd = 17.4 nM). Gel shift assays show BG4 binds to inter- and intramolecular G4-DNA, when it is in parallel orientation. Mere presence of G4-motif in duplex DNA is insufficient for antibody recognition. Importantly, BG4 can bind to G4-DNA within telomere sequence in a supercoiled plasmid. Finally, we show that BG4 binds to form efficient foci in four cell lines, irrespective of their lineage, demonstrating presence of G4-DNA in genome. Importantly, number of BG4 foci within the cells can be modulated, upon knockdown of G4-resolvase, WRN. Thus, we establish specificity of BG4 towards G4-DNA and discuss its potential applications.
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Affiliation(s)
- Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Namrata M Nilavar
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Amita Paranjape
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Kohal Das
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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8
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Ait Saada A, Costa AB, Sheng Z, Guo W, Haber JE, Lobachev K. Structural parameters of palindromic repeats determine the specificity of nuclease attack of secondary structures. Nucleic Acids Res 2021; 49:3932-3947. [PMID: 33772579 PMCID: PMC8053094 DOI: 10.1093/nar/gkab168] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/24/2021] [Accepted: 03/02/2021] [Indexed: 12/15/2022] Open
Abstract
Palindromic sequences are a potent source of chromosomal instability in many organisms and are implicated in the pathogenesis of human diseases. In this study, we investigate which nucleases are responsible for cleavage of the hairpin and cruciform structures and generation of double-strand breaks at inverted repeats in Saccharomyces cerevisiae. We demonstrate that the involvement of structure-specific nucleases in palindrome fragility depends on the distance between inverted repeats and their transcriptional status. The attack by the Mre11 complex is constrained to hairpins with loops <9 nucleotides. This restriction is alleviated upon RPA depletion, indicating that RPA controls the stability and/or formation of secondary structures otherwise responsible for replication fork stalling and DSB formation. Mus81-Mms4 cleavage of cruciforms occurs at divergently but not convergently transcribed or nontranscribed repeats. Our study also reveals the third pathway for fragility at perfect and quasi-palindromes, which involves cruciform resolution during the G2 phase of the cell cycle.
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Affiliation(s)
- Anissia Ait Saada
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GE 30332, USA
| | - Alex B Costa
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GE 30332, USA
| | - Ziwei Sheng
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GE 30332, USA
| | - Wenying Guo
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GE 30332, USA
| | - James E Haber
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Waltham, MA 02454-9110, USA
| | - Kirill S Lobachev
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GE 30332, USA
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9
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Svetec Miklenić M, Svetec IK. Palindromes in DNA-A Risk for Genome Stability and Implications in Cancer. Int J Mol Sci 2021; 22:2840. [PMID: 33799581 PMCID: PMC7999016 DOI: 10.3390/ijms22062840] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/04/2021] [Accepted: 03/08/2021] [Indexed: 02/07/2023] Open
Abstract
A palindrome in DNA consists of two closely spaced or adjacent inverted repeats. Certain palindromes have important biological functions as parts of various cis-acting elements and protein binding sites. However, many palindromes are known as fragile sites in the genome, sites prone to chromosome breakage which can lead to various genetic rearrangements or even cell death. The ability of certain palindromes to initiate genetic recombination lies in their ability to form secondary structures in DNA which can cause replication stalling and double-strand breaks. Given their recombinogenic nature, it is not surprising that palindromes in the human genome are involved in genetic rearrangements in cancer cells as well as other known recurrent translocations and deletions associated with certain syndromes in humans. Here, we bring an overview of current understanding and knowledge on molecular mechanisms of palindrome recombinogenicity and discuss possible implications of DNA palindromes in carcinogenesis. Furthermore, we overview the data on known palindromic sequences in the human genome and efforts to estimate their number and distribution, as well as underlying mechanisms of genetic rearrangements specific palindromic sequences cause.
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Affiliation(s)
| | - Ivan Krešimir Svetec
- Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia;
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10
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Alternative DNA Structures In Vivo: Molecular Evidence and Remaining Questions. Microbiol Mol Biol Rev 2020; 85:85/1/e00110-20. [PMID: 33361270 DOI: 10.1128/mmbr.00110-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Duplex DNA naturally folds into a right-handed double helix in physiological conditions. Some sequences of unusual base composition may nevertheless form alternative structures, as was shown for many repeated sequences in vitro However, evidence for the formation of noncanonical structures in living cells is difficult to gather. It mainly relies on genetic assays demonstrating their function in vivo or through genetic instability reflecting particular properties of such structures. Efforts were made to reveal their existence directly in a living cell, mainly by generating antibodies specific to secondary structures or using chemical ligands selected for their affinity to these structures. Among secondary structure-forming DNAs are G-quadruplexes, human fragile sites containing minisatellites, AT-rich regions, inverted repeats able to form cruciform structures, hairpin-forming CAG/CTG triplet repeats, and triple helices formed by homopurine-homopyrimidine GAA/TTC trinucleotide repeats. Many of these alternative structures are involved in human pathologies, such as neurological or developmental disorders, as in the case of trinucleotide repeats, or cancers triggered by translocations linked to fragile sites. This review will discuss and highlight evidence supporting the formation of alternative DNA structures in vivo and will emphasize the role of the mismatch repair machinery in binding mispaired DNA duplexes, triggering genetic instability.
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Correll-Tash S, Lilley B, Salmons Iv H, Mlynarski E, Franconi CP, McNamara M, Woodbury C, Easley CA, Emanuel BS. Double strand breaks (DSBs) as indicators of genomic instability in PATRR-mediated translocations. Hum Mol Genet 2020; 29:3872-3881. [PMID: 33258468 DOI: 10.1093/hmg/ddaa251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 10/05/2020] [Accepted: 11/25/2020] [Indexed: 02/06/2023] Open
Abstract
Genomic instability contributes to a variety of potentially damaging conditions, including DNA-based rearrangements. Breakage in the form of double strand breaks (DSBs) increases the likelihood of DNA damage, mutations and translocations. Certain human DNA regions are known to be involved in recurrent translocations, such as the palindrome-mediated rearrangements that have been identified at the breakpoints of several recurrent constitutional translocations: t(11;22)(q23;q11), t(17;22)(q11;q11) and t(8;22) (q24;q11). These breakpoints occur at the center of palindromic AT-rich repeats (PATRRs), which suggests that the structure of the DNA may play a contributory role, potentially through the formation of secondary cruciform structures. The current study analyzed the DSB propensity of these PATRR regions in both lymphoblastoid (mitotic) and spermatogenic cells (meiotic). Initial results found an increased association of sister chromatid exchanges (SCEs) at PATRR regions in experiments that used SCEs to assay DSBs, combining SCE staining with fluorescence in situ hybridization (FISH). Additional experiments used chromatin immunoprecipitation (ChIP) with antibodies for either markers of DSBs or proteins involved in DSB repair along with quantitative polymerase chain reaction to quantify the frequency of DSBs occurring at PATRR regions. The results indicate an increased rate of DSBs at PATRR regions. Additional ChIP experiments with the cruciform binding 2D3 antibody indicate an increased rate of cruciform structures at PATRR regions in both mitotic and meiotic samples. Overall, these experiments demonstrate an elevated rate of DSBs at PATRR regions, an indication that the structure of PATRR containing DNA may lead to increased breakage in multiple cellular environments.
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Affiliation(s)
- Sarah Correll-Tash
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Brenna Lilley
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Harold Salmons Iv
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Elisabeth Mlynarski
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Colleen P Franconi
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Meghan McNamara
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Carson Woodbury
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Charles A Easley
- Department of Environmental Health Sciences, College of Public Health at the University of Georgia, Athens, GA, 30602, USA
| | - Beverly S Emanuel
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.,Department of Pediatrics, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA 19104, USA
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12
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Abstract
Mutation of the human genome results in three classes of genomic variation: single nucleotide variants; short insertions or deletions; and large structural variants (SVs). Some mutations occur during normal processes, such as meiotic recombination or B cell development, and others result from DNA replication or aberrant repair of breaks in sequence-specific contexts. Regardless of mechanism, mutations are subject to selection, and some hotspots can manifest in disease. Here, we discuss genomic regions prone to mutation, mechanisms contributing to mutation susceptibility, and the processes leading to their accumulation in normal and somatic genomes. With further, more accurate human genome sequencing, additional mutation hotspots, mechanistic details of their formation, and the relevance of hotspots to evolution and disease are likely to be discovered.
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13
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Feng X, Xie FY, Ou XH, Ma JY. Cruciform DNA in mouse growing oocytes: Its dynamics and its relationship with DNA transcription. PLoS One 2020; 15:e0240844. [PMID: 33079963 PMCID: PMC7575099 DOI: 10.1371/journal.pone.0240844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/04/2020] [Indexed: 01/22/2023] Open
Abstract
Cruciform DNA is a causing factor of genome instability and chromosomal translocation, however, most studies about cruciform DNA in mammalian cells were based on palindromic sequences containing plasmids and reports about endogenous cruciform DNA are rare. In this study we observed the dynamics of endogenous cruciform DNA in mouse growing oocytes using immunofluorescence labeling method. We found cruciform DNA foci exist in transcription active growing oocytes but not in transcription inactive fully grown oocytes and colocalized with Parp1 but not with DNA damage marker γH2A.X. By analyzing the Genotype-Tissue Expression data, we found cruciform DNA-mediated chromosomal translocation in human spermatocytes is associated with the specific DNA transcription in testis. When inhibiting the transcription with α-amanitin in mouse oocytes, we found oocyte cruciform DNA foci decreased significantly. In summary, we observed the endogenous cruciform DNA in growing oocytes and our results showed that the cruciform DNA formation is transcription-dependent.
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Affiliation(s)
- Xie Feng
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Feng-Yun Xie
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Xiang-Hong Ou
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
- * E-mail: (J-YM); (X-HO)
| | - Jun-Yu Ma
- Fertility Preservation Lab, Reproductive Medicine Center, Guangdong Second Provincial General Hospital, Guangzhou, China
- * E-mail: (J-YM); (X-HO)
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14
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Wang G, Sukumar S. Unpredicted central inversion in a sgRNA flanked by inverted repeats. Mol Biol Rep 2020; 47:6375-6378. [PMID: 32424520 DOI: 10.1007/s11033-020-05524-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
In genome engineering, sgRNAs define the genomic target to be modified in CRISPR/Cas9 system. Either for single gene editing or genome-wide screens, sgRNAs are cloned into plasmid vectors. During our performance of CRISPR/Cas9 gene knock out, we found that the central part of a sgRNA was inverted after transformation into Escherichia coli. Interestingly, the inverted portion was found to be flanked by inverted repeats, and sealing of nicks inside the plasmid could correct the inversion. This type of sgRNA recombination completely changed its original sequence and should be noted during sgRNA design and performance of CRISPR/Cas9.
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Affiliation(s)
- Guannan Wang
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei, China.
- Lombardi Comprehensive Cancer Center, Georgetown University, 3970 Reservoir Rd NW, New Research Building, Room E512, Washington, D.C., 20007, USA.
| | - Saraswati Sukumar
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
- Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, CRB1/Room 143, Baltimore, MD, 21287, USA.
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15
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Global analysis of inverted repeat sequences in human gene promoters reveals their non-random distribution and association with specific biological pathways. Genomics 2020; 112:2772-2777. [DOI: 10.1016/j.ygeno.2020.03.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/02/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022]
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16
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Svetec Miklenić M, Gatalica N, Matanović A, Žunar B, Štafa A, Lisnić B, Svetec IK. Size-dependent antirecombinogenic effect of short spacers on palindrome recombinogenicity. DNA Repair (Amst) 2020; 90:102848. [PMID: 32388488 DOI: 10.1016/j.dnarep.2020.102848] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 03/21/2020] [Accepted: 03/28/2020] [Indexed: 01/01/2023]
Abstract
Palindromic sequences in DNA can instigate genetic recombination and genome instability, which can result in devastating conditions such as the Emmanuel syndrome. Palindrome recombinogenicity increases with its size and sequence similarity between palindrome arms, while quasipalindromes with long spacers are less recombinogenic. However, the minimal spacer length, which could reduce or abolish palindrome recombinogenicity in the eukaryotic genome, was never determined. Therefore, we constructed a series of palindromes containing spacers of lengths ranging from 0 (perfect palindrome) to 10 bp and tested their recombinogenicity in yeast Saccharomyces cerevisiae. We found that a 7 bp spacer significantly reduces 126 bp palindrome recombinogenicity, while a 10 bp spacer completely stabilizes palindromes up to 150 bp long. Additionally, we showed that palindrome stimulated recombination rate is not dependent on Mus81 and Yen1 endonucleases. We also compared the recombinogenicity of a perfect 126 bp palindrome and a corresponding quasipalindrome consisting of the same palindrome arms with a stabilising 10 bp spacer in sgs1Δ and rad27Δ backgrounds, since both Sgs1 helicase and Rad27 endonuclease are implicated in preventing hairpin formation at palindromic sequences during replication.
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Affiliation(s)
- Marina Svetec Miklenić
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Nikolina Gatalica
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Angela Matanović
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Bojan Žunar
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Anamarija Štafa
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Berislav Lisnić
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia
| | - Ivan Krešimir Svetec
- Laboratory for Biology and Microbial Genetics, Department of Biochemical Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, 10000 Zagreb, Croatia.
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17
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Tan M, Takahashi N, Fujii S, Sakurai K, Kusamori K, Takahashi Y, Takakura Y, Nishikawa M. Analysis of Tertiary Structural Features of Branched DNA Nanostructures with Partially Common Sequences Using Small-Angle X-ray Scattering. ACS APPLIED BIO MATERIALS 2019; 3:308-314. [DOI: 10.1021/acsabm.9b00829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mengmeng Tan
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Natsuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shota Fujii
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan
| | - Kazuo Sakurai
- Department of Chemistry and Biochemistry, University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan
- Structural Materials Science Laboratory SPring-8 Center, RIKEN Harima Institute Research, 1-1-1 Kouto, Sayo-cho, Sayo, Hyogo 679-5148, Japan
| | - Kosuke Kusamori
- Laboratory of Biopharmaceutics, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Makiya Nishikawa
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29, Yoshidashimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
- Laboratory of Biopharmaceutics, Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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18
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Ruiz-Ruano FJ, Navarro-Domínguez B, Camacho JPM, Garrido-Ramos MA. Full plastome sequence of the fern Vandenboschia speciosa (Hymenophyllales): structural singularities and evolutionary insights. JOURNAL OF PLANT RESEARCH 2019; 132:3-17. [PMID: 30552526 DOI: 10.1007/s10265-018-1077-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/26/2018] [Indexed: 05/14/2023]
Abstract
We provide here the first full chloroplast genome sequence, i.e., the plastome, for a species belonging to the fern order Hymenophyllales. The phylogenetic position of this order within leptosporangiate ferns, together with the general scarcity of information about fern plastomes, places this research as a valuable study on the analysis of the diversity of plastomes throughout fern evolution. Gene content of V. speciosa plastome was similar to that in most ferns, although there were some characteristic gene losses and lineage-specific differences. In addition, an important number of genes required U to C RNA editing for proper protein translation and two genes showed start codons alternative to the canonical AUG (AUA). Concerning gene order, V. speciosa shared the specific 30-kb inversion of euphyllophytes plastomes and the 3.3-kb inversion of fern plastomes, keeping the ancestral gene order shared by eusporangiate and early leptosporangiate ferns. Conversely, V. speciosa has expanded IR regions comprising the rps7, rps12, ndhB and trnL genes in addition to rRNA and other tRNA genes, a condition shared with several eusporangiate ferns, lycophytes and hornworts, as well as most seed plants.
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Affiliation(s)
- F J Ruiz-Ruano
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - B Navarro-Domínguez
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - J P M Camacho
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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19
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Miura O, Ogake T, Yoneyama H, Kikuchi Y, Ohyama T. A strong structural correlation between short inverted repeat sequences and the polyadenylation signal in yeast and nucleosome exclusion by these inverted repeats. Curr Genet 2018; 65:575-590. [PMID: 30498953 PMCID: PMC6420913 DOI: 10.1007/s00294-018-0907-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 11/22/2022]
Abstract
DNA sequences that read the same from 5′ to 3′ in either strand are called inverted repeat sequences or simply IRs. They are found throughout a wide variety of genomes, from prokaryotes to eukaryotes. Despite extensive research, their in vivo functions, if any, remain unclear. Using Saccharomyces cerevisiae, we performed genome-wide analyses for the distribution, occurrence frequency, sequence characteristics and relevance to chromatin structure, for the IRs that reportedly have a cruciform-forming potential. Here, we provide the first comprehensive map of these IRs in the S. cerevisiae genome. The statistically significant enrichment of the IRs was found in the close vicinity of the DNA positions corresponding to polyadenylation [poly(A)] sites and ~ 30 to ~ 60 bp downstream of start codon-coding sites (referred to as ‘start codons’). In the former, ApT- or TpA-rich IRs and A-tract- or T-tract-rich IRs are enriched, while in the latter, different IRs are enriched. Furthermore, we found a strong structural correlation between the former IRs and the poly(A) signal. In the chromatin formed on the gene end regions, the majority of the IRs causes low nucleosome occupancy. The IRs in the region ~ 30 to ~ 60 bp downstream of start codons are located in the + 1 nucleosomes. In contrast, fewer IRs are present in the adjacent region downstream of start codons. The current study suggests that the IRs play similar roles in Escherichia coli and S. cerevisiae to regulate or complete transcription at the RNA level.
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Affiliation(s)
- Osamu Miura
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Toshihiro Ogake
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Hiroki Yoneyama
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Yo Kikuchi
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Takashi Ohyama
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan. .,Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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20
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Guiblet WM, Cremona MA, Cechova M, Harris RS, Kejnovská I, Kejnovsky E, Eckert K, Chiaromonte F, Makova KD. Long-read sequencing technology indicates genome-wide effects of non-B DNA on polymerization speed and error rate. Genome Res 2018; 28:1767-1778. [PMID: 30401733 PMCID: PMC6280752 DOI: 10.1101/gr.241257.118] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/30/2018] [Indexed: 12/14/2022]
Abstract
DNA conformation may deviate from the classical B-form in ∼13% of the human genome. Non-B DNA regulates many cellular processes; however, its effects on DNA polymerization speed and accuracy have not been investigated genome-wide. Such an inquiry is critical for understanding neurological diseases and cancer genome instability. Here, we present the first simultaneous examination of DNA polymerization kinetics and errors in the human genome sequenced with Single-Molecule Real-Time (SMRT) technology. We show that polymerization speed differs between non-B and B-DNA: It decelerates at G-quadruplexes and fluctuates periodically at disease-causing tandem repeats. Analyzing polymerization kinetics profiles, we predict and validate experimentally non-B DNA formation for a novel motif. We demonstrate that several non-B motifs affect sequencing errors (e.g., G-quadruplexes increase error rates), and that sequencing errors are positively associated with polymerase slowdown. Finally, we show that highly divergent G4 motifs have pronounced polymerization slowdown and high sequencing error rates, suggesting similar mechanisms for sequencing errors and germline mutations.
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Affiliation(s)
- Wilfried M Guiblet
- Bioinformatics and Genomics Graduate Program, Penn State University, University Park, Pennsylvania 16802, USA
| | - Marzia A Cremona
- Department of Statistics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Monika Cechova
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
| | - Robert S Harris
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
| | - Iva Kejnovská
- Department of Biophysics of Nucleic Acids, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Eduard Kejnovsky
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Kristin Eckert
- Department of Pathology, Penn State University, College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Francesca Chiaromonte
- Department of Statistics, Penn State University, University Park, Pennsylvania 16802, USA.,Sant'Anna School of Advanced Studies, 56127 Pisa, Italy
| | - Kateryna D Makova
- Department of Biology, Penn State University, University Park, Pennsylvania 16802, USA
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Miura O, Ogake T, Ohyama T. Requirement or exclusion of inverted repeat sequences with cruciform-forming potential in Escherichia coli revealed by genome-wide analyses. Curr Genet 2018; 64:945-958. [PMID: 29484452 PMCID: PMC6060812 DOI: 10.1007/s00294-018-0815-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/16/2018] [Accepted: 02/19/2018] [Indexed: 12/31/2022]
Abstract
Inverted repeat (IR) sequences are DNA sequences that read the same from 5' to 3' in each strand. Some IRs can form cruciforms under the stress of negative supercoiling, and these IRs are widely found in genomes. However, their biological significance remains unclear. The aim of the current study is to explore this issue further. We constructed the first Escherichia coli genome-wide comprehensive map of IRs with cruciform-forming potential. Based on the map, we performed detailed and quantitative analyses. Here, we report that IRs with cruciform-forming potential are statistically enriched in the following five regions: the adjacent regions downstream of the stop codon-coding sites (referred to as the stop codons), on and around the positions corresponding to mRNA ends (referred to as the gene ends), ~ 20 to ~45 bp upstream of the start codon-coding sites (referred to as the start codons) within the 5'-UTR (untranslated region), ~ 25 to ~ 60 bp downstream of the start codons, and promoter regions. For the adjacent regions downstream of the stop codons and on and around the gene ends, most of the IRs with a repeat unit length of ≥ 8 bp and a spacer size of ≤ 8 bp were parts of the intrinsic terminators, regardless of the location, and presumably used for Rho-independent transcription termination. In contrast, fewer IRs were present in the small region preceding the start codons. In E. coli, IRs with cruciform-forming potential are actively placed or excluded in the regulatory regions for the initiation and termination of transcription and translation, indicating their deep involvement or influence in these processes.
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Affiliation(s)
- Osamu Miura
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Toshihiro Ogake
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Takashi Ohyama
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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22
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Inagaki H, Kato T, Tsutsumi M, Ouchi Y, Ohye T, Kurahashi H. Palindrome-Mediated Translocations in Humans: A New Mechanistic Model for Gross Chromosomal Rearrangements. Front Genet 2016; 7:125. [PMID: 27462347 PMCID: PMC4940405 DOI: 10.3389/fgene.2016.00125] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/28/2016] [Indexed: 11/13/2022] Open
Abstract
Palindromic DNA sequences, which can form secondary structures, are widely distributed in the human genome. Although the nature of the secondary structure-single-stranded "hairpin" or double-stranded "cruciform"-has been extensively investigated in vitro, the existence of such unusual non-B DNA in vivo remains controversial. Here, we review palindrome-mediated gross chromosomal rearrangements possibly induced by non-B DNA in humans. Recent advances in next-generation sequencing have not yet overcome the difficulty of palindromic sequence analysis. However, a dozen palindromic AT-rich repeat (PATRR) sequences have been identified at the breakpoints of recurrent or non-recurrent chromosomal translocations in humans. The breakages always occur at the center of the palindrome. Analyses of polymorphisms within the palindromes indicate that the symmetry and length of the palindrome affect the frequency of the de novo occurrence of these palindrome-mediated translocations, suggesting the involvement of non-B DNA. Indeed, experiments using a plasmid-based model system showed that the formation of non-B DNA is likely the key to palindrome-mediated genomic rearrangements. Some evidence implies a new mechanism that cruciform DNAs may come close together first in nucleus and illegitimately joined. Analysis of PATRR-mediated translocations in humans will provide further understanding of gross chromosomal rearrangements in many organisms.
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Affiliation(s)
- Hidehito Inagaki
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health UniversityToyoake, Japan; Genome and Transcriptome Analysis Center, Fujita Health UniversityToyoake, Japan
| | - Takema Kato
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University Toyoake, Japan
| | - Makiko Tsutsumi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University Toyoake, Japan
| | - Yuya Ouchi
- Genome and Transcriptome Analysis Center, Fujita Health University Toyoake, Japan
| | - Tamae Ohye
- Department of Molecular Laboratory Medicine, Faculty of Medical Technology, School of Health Science, Fujita Health University Toyoake, Japan
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health UniversityToyoake, Japan; Genome and Transcriptome Analysis Center, Fujita Health UniversityToyoake, Japan
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23
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Bacolla A, Tainer JA, Vasquez KM, Cooper DN. Translocation and deletion breakpoints in cancer genomes are associated with potential non-B DNA-forming sequences. Nucleic Acids Res 2016; 44:5673-88. [PMID: 27084947 PMCID: PMC4937311 DOI: 10.1093/nar/gkw261] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/30/2016] [Indexed: 12/13/2022] Open
Abstract
Gross chromosomal rearrangements (including translocations, deletions, insertions and duplications) are a hallmark of cancer genomes and often create oncogenic fusion genes. An obligate step in the generation of such gross rearrangements is the formation of DNA double-strand breaks (DSBs). Since the genomic distribution of rearrangement breakpoints is non-random, intrinsic cellular factors may predispose certain genomic regions to breakage. Notably, certain DNA sequences with the potential to fold into secondary structures [potential non-B DNA structures (PONDS); e.g. triplexes, quadruplexes, hairpin/cruciforms, Z-DNA and single-stranded looped-out structures with implications in DNA replication and transcription] can stimulate the formation of DNA DSBs. Here, we tested the postulate that these DNA sequences might be found at, or in close proximity to, rearrangement breakpoints. By analyzing the distribution of PONDS-forming sequences within ±500 bases of 19 947 translocation and 46 365 sequence-characterized deletion breakpoints in cancer genomes, we find significant association between PONDS-forming repeats and cancer breakpoints. Specifically, (AT)n, (GAA)n and (GAAA)n constitute the most frequent repeats at translocation breakpoints, whereas A-tracts occur preferentially at deletion breakpoints. Translocation breakpoints near PONDS-forming repeats also recur in different individuals and patient tumor samples. Hence, PONDS-forming sequences represent an intrinsic risk factor for genomic rearrangements in cancer genomes.
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Affiliation(s)
- Albino Bacolla
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Ave., Houston, TX 77030, USA Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Ave., Houston, TX 77030, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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Abstract
During meiosis, numerous DNA double-strand breaks (DSBs) are formed as part of the normal developmental program. This seemingly destructive behavior is necessary for successful meiosis, since repair of the DSBs through homologous recombination (HR) helps to produce physical links between the homologous chromosomes essential for correct chromosome segregation later in meiosis. However, DSB formation at such a massive scale also introduces opportunities to generate gross chromosomal rearrangements. In this review, we explore ways in which meiotic DSBs can result in such genomic alterations.
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25
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Delihas N. Complexity of a small non-protein coding sequence in chromosomal region 22q11.2: presence of specialized DNA secondary structures and RNA exon/intron motifs. BMC Genomics 2015; 16:785. [PMID: 26467088 PMCID: PMC4607176 DOI: 10.1186/s12864-015-1958-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 09/28/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND DiGeorge Syndrome is a genetic abnormality involving ~3 Mb deletion in human chromosome 22, termed 22q.11.2. To better understand the non-coding regions of 22q.11.2, a small 10,000 bp non-protein-coding sequence close to the DiGeorge Critical Region 6 gene (DGCR6) was chosen for analysis and functional entities as the homologous sequence in the chimpanzee genome could be aligned and used for comparisons. METHODS The GenBank database provided genomic sequences. In silico computer programs were used to find homologous DNA sequences in human and chimpanzee genomes, generate random sequences, determine DNA sequence alignments, sequence comparisons and nucleotide repeat copies, and to predicted DNA secondary structures. RESULTS At its 5' half, the 10,000 bp sequence has three distinct sections that represent phylogenetically variable sequences. These Variable Regions contain biased mutations with a very high A + T content, multiple copies of the motif TATAATATA and sequences that fold into long A:T-base-paired stem loops. The 3' half of the 10,000 bp unit, highly conserved between human and chimpanzee, has sequences representing exons of lncRNA genes and segments of introns of protein genes. Central to the 10,000 bp unit are the multiple copies of a sequence that originates from the flanking 5' end of the translocation breakpoint Type A sequence. This breakpoint flanking sequence carries the exon and intron motifs. The breakpoint Type A sequence seems to be a major player in the proliferation of these RNA motifs, as well as the proliferation of Variable Regions in the 10,000 bp segment and other regions within 22q.11.2. CONCLUSIONS The data indicate that a non-coding region of the chromosome may be reserved for highly biased mutations that lead to formation of specialized sequences and DNA secondary structures. On the other hand, the highly conserved nucleotide sequence of the non-coding region may form storage sites for RNA motifs.
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Affiliation(s)
- Nicholas Delihas
- Department of Molecular Genetics and Microbiology, School of Medicine, Stony, Brook University, Stony Brook, NY, 11794, USA.
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26
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Lim CT, Lai PJ, Leach DRF, Maki H, Furukohri A. A novel mode of nuclease action is revealed by the bacterial Mre11/Rad50 complex. Nucleic Acids Res 2015; 43:9804-16. [PMID: 26319016 PMCID: PMC4787754 DOI: 10.1093/nar/gkv855] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/12/2015] [Indexed: 11/14/2022] Open
Abstract
The Mre11/Rad50 complex is a central player in various genome maintenance pathways. Here, we report a novel mode of nuclease action found for the Escherichia coli Mre11/Rad50 complex, SbcC2/D2 complex (SbcCD). SbcCD cuts off the top of a cruciform DNA by making incisions on both strands and continues cleaving the dsDNA stem at ∼10-bp intervals. Using linear-shaped DNA substrates, we observed that SbcCD cleaved dsDNA using this activity when the substrate was 110 bp long, but that on shorter substrates the cutting pattern was changed to that predicted for the activity of a 3′-5′ exonuclease. Our results suggest that SbcCD processes hairpin and linear dsDNA ends with this novel DNA end-dependent binary endonuclease activity in response to substrate length rather than using previously reported activities. We propose a model for this mode of nuclease action, which provides new insight into SbcCD activity at a dsDNA end.
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Affiliation(s)
- Chew Theng Lim
- Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Pey Jiun Lai
- Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - David R F Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Kings Buildings, Edinburgh EH9 3JR, UK
| | - Hisaji Maki
- Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Asako Furukohri
- Division of Systems Biology, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
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27
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Javadekar SM, Raghavan SC. Snaps and mends: DNA breaks and chromosomal translocations. FEBS J 2015; 282:2627-45. [PMID: 25913527 DOI: 10.1111/febs.13311] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 03/29/2015] [Accepted: 04/23/2015] [Indexed: 01/11/2023]
Abstract
Integrity in entirety is the preferred state of any organism. The temporal and spatial integrity of the genome ensures continued survival of a cell. DNA breakage is the first step towards creation of chromosomal translocations. In this review, we highlight the factors contributing towards the breakage of chromosomal DNA. It has been well-established that the structure and sequence of DNA play a critical role in selective fragility of the genome. Several non-B-DNA structures such as Z-DNA, cruciform DNA, G-quadruplexes, R loops and triplexes have been implicated in generation of genomic fragility leading to translocations. Similarly, specific sequences targeted by proteins such as Recombination Activating Genes and Activation Induced Cytidine Deaminase are involved in translocations. Processes that ensure the integrity of the genome through repair may lead to persistence of breakage and eventually translocations if their actions are anomalous. An insufficient supply of nucleotides and chromatin architecture may also play a critical role. This review focuses on a range of events with the potential to threaten the genomic integrity of a cell, leading to cancer.
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Affiliation(s)
- Saniya M Javadekar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sathees C Raghavan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Thys RG, Lehman CE, Pierce LCT, Wang YH. DNA secondary structure at chromosomal fragile sites in human disease. Curr Genomics 2015; 16:60-70. [PMID: 25937814 PMCID: PMC4412965 DOI: 10.2174/1389202916666150114223205] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 11/22/2022] Open
Abstract
DNA has the ability to form a variety of secondary structures that can interfere with normal cellular processes, and many of these structures have been associated with neurological diseases and cancer. Secondary structure-forming sequences are often found at chromosomal fragile sites, which are hotspots for sister chromatid exchange, chromosomal translocations, and deletions. Structures formed at fragile sites can lead to instability by disrupting normal cellular processes such as DNA replication and transcription. The instability caused by disruption of replication and transcription can lead to DNA breakage, resulting in gene rearrangements and deletions that cause disease. In this review, we discuss the role of DNA secondary structure at fragile sites in human disease.
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Affiliation(s)
- Ryan G Thys
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
| | - Christine E Lehman
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
| | | | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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Lu S, Wang G, Bacolla A, Zhao J, Spitser S, Vasquez KM. Short Inverted Repeats Are Hotspots for Genetic Instability: Relevance to Cancer Genomes. Cell Rep 2015; 10:1674-1680. [PMID: 25772355 DOI: 10.1016/j.celrep.2015.02.039] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 01/26/2015] [Accepted: 02/16/2015] [Indexed: 12/25/2022] Open
Abstract
Analyses of chromosomal aberrations in human genetic disorders have revealed that inverted repeat sequences (IRs) often co-localize with endogenous chromosomal instability and breakage hotspots. Approximately 80% of all IRs in the human genome are short (<100 bp), yet the mutagenic potential of such short cruciform-forming sequences has not been characterized. Here, we find that short IRs are enriched at translocation breakpoints in human cancer and stimulate the formation of DNA double-strand breaks (DSBs) and deletions in mammalian and yeast cells. We provide evidence for replication-related mechanisms of IR-induced genetic instability and a novel XPF cleavage-based mechanism independent of DNA replication. These discoveries implicate short IRs as endogenous sources of DNA breakage involved in disease etiology and suggest that these repeats represent a feature of genome plasticity that may contribute to the evolution of the human genome by providing a means for diversity within the population.
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Affiliation(s)
- Steve Lu
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA
| | - Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA
| | - Albino Bacolla
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA
| | - Junhua Zhao
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA
| | - Scott Spitser
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin - Dell Pediatric Research Institute, 1400 Barbara Jordan Boulevard R1800, Austin, TX 78723, USA.
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Azeroglu B, Lincker F, White MA, Jain D, Leach DRF. A perfect palindrome in the Escherichia coli chromosome forms DNA hairpins on both leading- and lagging-strands. Nucleic Acids Res 2014; 42:13206-13. [PMID: 25389268 PMCID: PMC4245961 DOI: 10.1093/nar/gku1136] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
DNA palindromes are hotspots for DNA double strand breaks, inverted duplications and intra-chromosomal translocations in a wide spectrum of organisms from bacteria to humans. These reactions are mediated by DNA secondary structures such as hairpins and cruciforms. In order to further investigate the pathways of formation and cleavage of these structures, we have compared the processing of a 460 base pair (bp) perfect palindrome in the Escherichia coli chromosome with the same construct interrupted by a 20 bp spacer to form a 480 bp interrupted palindrome. We show here that the perfect palindrome can form hairpin DNA structures on the templates of the leading- and lagging-strands in a replication-dependent reaction. In the presence of the hairpin endonuclease SbcCD, both copies of the replicated chromosome containing the perfect palindrome are cleaved, resulting in the formation of an unrepairable DNA double-strand break and cell death. This contrasts with the interrupted palindrome, which forms a hairpin on the lagging-strand template that is processed to form breaks, which can be repaired by homologous recombination.
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Affiliation(s)
- Benura Azeroglu
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - Frédéric Lincker
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - Martin A White
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - Devanshi Jain
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
| | - David R F Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3BF, UK
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Palindromic GOLGA8 core duplicons promote chromosome 15q13.3 microdeletion and evolutionary instability. Nat Genet 2014; 46:1293-302. [PMID: 25326701 PMCID: PMC4244265 DOI: 10.1038/ng.3120] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022]
Abstract
Recurrent deletions of chromosome 15q13.3 associate with intellectual disability, schizophrenia, autism and epilepsy. To gain insight into its instability, we sequenced the region in patients, normal individuals and nonhuman primates. We discovered five structural configurations of the human chromosome 15q13.3 region ranging in size from 2 to 3 Mbp. These configurations arose recently (~0.5–0.9 million years ago) as a result of human-specific expansions of segmental duplications and two independent inversion events. All inversion breakpoints map near GOLGA8 core duplicons—a ~14 kbp primate-specific chromosome 15 repeat that became organized into larger palindromic structures. GOLGA8-flanked palindromes also demarcate the breakpoints of recurrent 15q13.3 microdeletions, the expansion of chromosome 15 segmental duplications in the human lineage, and independent structural changes in apes. The significant clustering (p=0.002) of breakpoints provides mechanistic evidence for the role of this core duplicon and its palindromic architecture in promoting evolutionary and disease-related instability of chromosome 15.
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Chan YW, West SC. Spatial control of the GEN1 Holliday junction resolvase ensures genome stability. Nat Commun 2014; 5:4844. [PMID: 25209024 PMCID: PMC4172962 DOI: 10.1038/ncomms5844] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/29/2014] [Indexed: 12/19/2022] Open
Abstract
Holliday junction (HJ) resolvases are necessary for the processing of persistent recombination intermediates before cell division. Their actions, however, need to be restricted to the late stages of the cell cycle to avoid the inappropriate cleavage of replication intermediates. Control of the yeast HJ resolvase, Yen1, involves phosphorylation changes that modulate its catalytic activity and nuclear import. Here, we show that GEN1, the human ortholog of Yen1, is regulated by a different mechanism that is independent of phosphorylation. GEN1 is controlled exclusively by nuclear exclusion, driven by a nuclear export signal (NES) that restricts GEN1 actions to mitosis when the nuclear membrane breaks down. Construction of a nuclear-localized version of GEN1 revealed that its premature actions partially suppress phenotypes associated with loss of BLM and MUS81, but cause elevated crossover formation. The spatial control of GEN1 therefore contributes to genome stability, by avoiding competition with non-crossover promoting repair pathways.
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Affiliation(s)
- Ying Wai Chan
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
| | - Stephen C. West
- London Research Institute, Cancer Research UK, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK
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Mishra D, Kato T, Inagaki H, Kosho T, Wakui K, Kido Y, Sakazume S, Taniguchi-Ikeda M, Morisada N, Iijima K, Fukushima Y, Emanuel BS, Kurahashi H. Breakpoint analysis of the recurrent constitutional t(8;22)(q24.13;q11.21) translocation. Mol Cytogenet 2014; 7:55. [PMID: 25478009 PMCID: PMC4255720 DOI: 10.1186/s13039-014-0055-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/25/2014] [Indexed: 11/23/2022] Open
Abstract
Backgrounds The t(8;22)(q24.13;q11.2) has been identified as one of several recurrent
constitutional translocations mediated by palindromic AT-rich repeats (PATRRs).
Although the breakage on 22q11 utilizes the same PATRR as that of the more
prevalent constitutional t(11;22)(q23;q11.2), the breakpoint region on 8q24 has
not been elucidated in detail since the analysis of palindromic sequence is
technically challenging. Results In this study, the entire 8q24 breakpoint region has been resolved by next
generation sequencing. Eight polymorphic alleles were identified and compared with
the junction sequences of previous and two recently identified t(8;22) cases . All
of the breakpoints were found to be within the PATRRs on chromosomes 8 and 22
(PATRR8 and PATRR22), but the locations were different among cases at the level of
nucleotide resolution. The translocations were always found to arise on symmetric
PATRR8 alleles with breakpoints at the center of symmetry. The translocation
junction is often accompanied by symmetric deletions at the center of both PATRRs.
Rejoining occurs with minimal homology between the translocation partners.
Remarkably, comparison of der (8) to der(22) sequences shows identical breakpoint
junctions between them, which likely represent products of two independent events
on the basis of a classical model. Conclusions Our data suggest the hypothesis that interactions between the two PATRRs prior to
the translocation event might trigger illegitimate recombination resulting in the
recurrent palindrome-mediated translocation.
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Affiliation(s)
- Divya Mishra
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan
| | - Takema Kato
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan
| | - Hidehito Inagaki
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan
| | - Tomoki Kosho
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto 390-8621, Nagano, Japan
| | - Keiko Wakui
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto 390-8621, Nagano, Japan
| | - Yasuhiro Kido
- Department of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Koshigaya 343-8555, Saitama, Japan
| | - Satoru Sakazume
- Department of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Koshigaya 343-8555, Saitama, Japan
| | - Mariko Taniguchi-Ikeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Hyogo, Japan
| | - Yoshimitsu Fukushima
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto 390-8621, Nagano, Japan
| | - Beverly S Emanuel
- Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia 19104, PA, USA.,Department of Pediatrics, The Perelman School of Medicine of the University of Pennsylvania, Philadelphia 19104, PA, USA
| | - Hiroki Kurahashi
- Division of Molecular Genetics, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan
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Hsiao MC, Piotrowski A, Alexander J, Callens T, Fu C, Mikhail FM, Claes KBM, Messiaen L. Palindrome-mediated and replication-dependent pathogenic structural rearrangements within the NF1 gene. Hum Mutat 2014; 35:891-8. [PMID: 24760680 DOI: 10.1002/humu.22569] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/17/2014] [Indexed: 11/09/2022]
Abstract
Palindromic sequences can form hairpin structures or cruciform extrusions, which render them susceptible to genomic rearrangements. A 197-bp long palindromic AT-rich repeat (PATRR17) is located within intron 40 of the neurofibromatosis type 1 (NF1) gene (17q11.2). Through comprehensive NF1 analysis, we identified six unrelated patients with a rearrangement involving intron 40 (five deletions and one reciprocal translocation t(14;17)(q32;q11.2)). We hypothesized that PATRR17 may be involved in these rearrangements thereby causing NF1. Breakpoint cloning revealed that PATRR17 was indeed involved in all of the rearrangements. As microhomology was present at all breakpoint junctions of the deletions identified, and PATRR17 partner breakpoints were located within 7.1 kb upstream of PATRR17, fork stalling and template switching/microhomology-mediated break-induced replication was the most likely rearrangement mechanism. For the reciprocal translocation case, a 51 bp insertion at the translocation breakpoints mapped to a short sequence within PATRR17, proximal to the breakpoint, suggesting a multiple stalling and rereplication process, in contrast to previous studies indicating a purely replication-independent mechanism for PATRR-mediated translocations. In conclusion, we show evidence that PATRR17 is a hotspot for pathogenic intragenic deletions within the NF1 gene and suggest a novel replication-dependent mechanism for PATRR-mediated translocation.
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Affiliation(s)
- Meng-Chang Hsiao
- Medical Genomics Laboratory, Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
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Zhang Y, Saini N, Sheng Z, Lobachev KS. Genome-wide screen reveals replication pathway for quasi-palindrome fragility dependent on homologous recombination. PLoS Genet 2013; 9:e1003979. [PMID: 24339793 PMCID: PMC3855049 DOI: 10.1371/journal.pgen.1003979] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/12/2013] [Indexed: 02/07/2023] Open
Abstract
Inverted repeats capable of forming hairpin and cruciform structures present a threat to chromosomal integrity. They induce double strand breaks, which lead to gross chromosomal rearrangements, the hallmarks of cancers and hereditary diseases. Secondary structure formation at this motif has been proposed to be the driving force for the instability, albeit the mechanisms leading to the fragility are not well-understood. We carried out a genome-wide screen to uncover the genetic players that govern fragility of homologous and homeologous Alu quasi-palindromes in the yeast Saccharomyces cerevisiae. We found that depletion or lack of components of the DNA replication machinery, proteins involved in Fe-S cluster biogenesis, the replication-pausing checkpoint pathway, the telomere maintenance complex or the Sgs1-Top3-Rmi1 dissolvasome augment fragility at Alu-IRs. Rad51, a component of the homologous recombination pathway, was found to be required for replication arrest and breakage at the repeats specifically in replication-deficient strains. These data demonstrate that Rad51 is required for the formation of breakage-prone secondary structures in situations when replication is compromised while another mechanism operates in DSB formation in replication-proficient strains. Inverted repeats are found in many eukaryotic genomes including humans. They have a potential to cause chromosomal breakage and rearrangements that contribute to genome polymorphism and the development of diseases. Instability of inverted repeats is accounted for by their propensity to adopt DNA secondary structures that is negatively affected by the distance between the repeats and level of sequence divergence. However, the genetic factors that promote the abnormal structure formation or affect the ability of the repeats to break are largely unknown. Here, using a genome-wide screen we identified 38 mutants that destabilize imperfect human inverted Alu repeats and predispose them to breakage. The proteins that are required to maintain repeat stability belong to the core of the DNA replication machinery and to the accessory proteins that help replication fork to move through the difficult templates. Remarkably, when replication machinery is compromised, the proteins involved in homologous recombination promote the formation of secondary structures and replication block thereby triggering breakage at the inverted repeats. These results reveal a powerful pathway for the destabilization of chromosomes containing inverted repeats that requires the activity of homologous recombination.
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Affiliation(s)
- Yu Zhang
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Natalie Saini
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Ziwei Sheng
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - Kirill S. Lobachev
- School of Biology and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia, United States of America
- * E-mail:
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Boyer AS, Grgurevic S, Cazaux C, Hoffmann JS. The Human Specialized DNA Polymerases and Non-B DNA: Vital Relationships to Preserve Genome Integrity. J Mol Biol 2013; 425:4767-81. [DOI: 10.1016/j.jmb.2013.09.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 12/26/2022]
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Markowski DN, Nimzyk R, Belge G, Löning T, Helmke BM, Bullerdiek J. Molecular topography of the MED12-deleted region in smooth muscle tumors: a possible link between non-B DNA structures and hypermutability. Mol Cytogenet 2013; 6:23. [PMID: 23738817 PMCID: PMC3712005 DOI: 10.1186/1755-8166-6-23] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 04/24/2013] [Indexed: 01/22/2023] Open
Abstract
Background Deletions of the gene encoding mediator subcomplex 12 (MED12) in human smooth muscle tumors rank among the most frequent genomic alterations in human tumors at all. In a minority of these cases, small deletions are found. In an attempt to delineate key features of the deletions aimed at a better understanding of the molecular pathogenesis of uterine smooth muscle tumors we have analyzed 70 MED12 deletions including 46 cases from the literature and 24 own unpublished cases. Results The average length of the deletions was 18.7 bp ranging between 2 bp and 43 bp. While in general multitudes of 3 clearly dominated leaving the transcript in frame, deletions of 21, 24, 30, and 33 nucleotides were clearly underrepresented. Within the DNA segment affected deletion breakpoints were not randomly distributed. Most breakpoints clustered within the center of the segment where two peaks of breakpoint clusters could be distinguished. Interestingly, one of these clusters coincides with the loop of a putative folded non-B DNA structure whereas a much lower number of breaks noted in the 5′ and 3′ stem of the structure forming an intramolecular B-helix. The second cluster mainly consisting of 3′ breaks was located in a region downstream adjacent to the stem. Conclusion The present study describes for the first time main characteristics of MED12 deletions occurring in smooth muscle tumors. Interestingly, the non-random distribution of breakpoints within the deletion hotspot region may point to a role of non-canonical DNA structures for the occurrence of these mutations and the molecular pathogenesis of uterine smooth muscle tumors, respectively.
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