1
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Tang W, Liang P. The identification of retro-DNAs in primate genomes as DNA transposons mobilizing via retrotransposition. F1000Res 2024; 12:255. [PMID: 38915770 PMCID: PMC11195612 DOI: 10.12688/f1000research.130043.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/26/2024] Open
Abstract
Background Mobile elements (MEs) constitute a major portion of the genome in primates and other higher eukaryotes, and they play important role in genome evolution and gene function. MEs can be divided into two fundamentally different classes: DNA transposons which transpose in the genome in a "cut-and-paste" style, and retrotransposons which propagate in a "copy-and-paste" fashion via a process involving transcription and reverse-transcription. In primate genomes, DNA transposons are mostly dead, while many retrotransposons are still highly active. We report here the identification of a unique group of MEs, which we call "retro-DNAs", for their combined characteristics of these two fundamentally different ME classes. Methods A comparative computational genomic approach was used to analyze the reference genome sequences of 10 primate species consisting of five apes, four monkeys, and marmoset. Results From our analysis, we identified a total of 1,750 retro-DNAs, representing 748 unique insertion events in the genomes of ten primate species including human. These retro-DNAs contain sequences of DNA transposons but lack the terminal inverted repeats (TIRs), the hallmark of DNA transposons. Instead, they show characteristics of retrotransposons, such as polyA tails, longer target-site duplications (TSDs), and the "TT/AAAA" insertion site motif, suggesting the use of the L1-based target- primed reverse transcription (TPRT) mechanism. At least 40% of these retro-DNAs locate into genic regions, presenting potentials for impacting gene function. More interestingly, some retro-DNAs, as well as their parent sites, show certain levels of expression, suggesting that they have the potential to create more retro-DNA copies in the present primate genomes. Conclusions Although small in number, the identification of these retro-DNAs reveals a new mean for propagating DNA transposons in primate genomes without active canonical DNA transposon activity. Our data also suggest that the TPRT machinery may transpose a wider variety of DNA sequences in the genomes.
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Affiliation(s)
- Wangxiangfu Tang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
- Centre of Biotechnology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
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2
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Wang N, Jiao K, He J, Zhu B, Cheng N, Sun J, Chen L, Chen W, Gong L, Qiao K, Xi J, Wu Q, Zhao C, Zhu W. Diagnosis of Challenging Spinal Muscular Atrophy Cases with Long-Read Sequencing. J Mol Diagn 2024; 26:364-373. [PMID: 38490302 DOI: 10.1016/j.jmoldx.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/17/2024] [Accepted: 02/07/2024] [Indexed: 03/17/2024] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder primarily caused by the deletion or mutation of the survival motor neuron 1 (SMN1) gene. This study assesses the diagnostic potential of long-read sequencing (LRS) in three patients with SMA. For Patient 1, who has a heterozygous SMN1 deletion, LRS unveiled a missense mutation in SMN1 exon 5. In Patient 2, an Alu/Alu-mediated rearrangement covering the SMN1 promoter and exon 1 was identified through a blend of multiplex ligation-dependent probe amplification, LRS, and PCR across the breakpoint. The third patient, born to a consanguineous family, bore four copies of hybrid SMN genes. LRS determined the genomic structures, indicating two distinct hybrids of SMN2 exon 7 and SMN1 exon 8. However, a discrepancy was found between the SMN1/SMN2 ratio interpretations by LRS (0:2) and multiplex ligation-dependent probe amplification (0:4), which suggested a limitation of LRS in SMA diagnosis. In conclusion, this newly adapted long PCR-based third-generation sequencing introduces an additional avenue for SMA diagnosis.
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Affiliation(s)
- Ningning Wang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Kexin Jiao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jin He
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, and Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Bochen Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Nachuan Cheng
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jian Sun
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Lan Chen
- Department of Neurology, Nantong First People's Hospital, Nantong, China
| | - Wanjin Chen
- Department of Neurology and Institute of Neurology of First Affiliated Hospital, Institute of Neuroscience, and Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Lingyun Gong
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Kai Qiao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jianying Xi
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Qihan Wu
- Shanghai Ministry of Science and Technology Key Laboratory of Health and Disease Genomics, National Health Commission Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Shanghai, China
| | - Chongbo Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Wenhua Zhu
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China; National Center for Neurological Disorders, Shanghai, China; Huashan Rare Disease Center, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
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3
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Le Breton A, Bettencourt MP, Gendrel AV. Navigating the brain and aging: exploring the impact of transposable elements from health to disease. Front Cell Dev Biol 2024; 12:1357576. [PMID: 38476259 PMCID: PMC10927736 DOI: 10.3389/fcell.2024.1357576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/08/2024] [Indexed: 03/14/2024] Open
Abstract
Transposable elements (TEs) are mobile genetic elements that constitute on average 45% of mammalian genomes. Their presence and activity in genomes represent a major source of genetic variability. While this is an important driver of genome evolution, TEs can also have deleterious effects on their hosts. A growing number of studies have focused on the role of TEs in the brain, both in physiological and pathological contexts. In the brain, their activity is believed to be important for neuronal plasticity. In neurological and age-related disorders, aberrant activity of TEs may contribute to disease etiology, although this remains unclear. After providing a comprehensive overview of transposable elements and their interactions with the host, this review summarizes the current understanding of TE activity within the brain, during the aging process, and in the context of neurological and age-related conditions.
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Affiliation(s)
| | | | - Anne-Valerie Gendrel
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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4
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Audano PA, Beck CR. Small polymorphisms are a source of ancestral bias in structural variant breakpoint placement. Genome Res 2024; 34:7-19. [PMID: 38176712 PMCID: PMC10904011 DOI: 10.1101/gr.278203.123] [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: 06/20/2023] [Accepted: 01/02/2024] [Indexed: 01/06/2024]
Abstract
High-quality genome assemblies and sophisticated algorithms have increased sensitivity for a wide range of variant types, and breakpoint accuracy for structural variants (SVs, ≥50 bp) has improved to near base pair precision. Despite these advances, many SV breakpoint locations are subject to systematic bias affecting variant representation. To understand why SV breakpoints are inconsistent across samples, we reanalyzed 64 phased haplotypes constructed from long-read assemblies released by the Human Genome Structural Variation Consortium (HGSVC). We identify 882 SV insertions and 180 SV deletions with variable breakpoints not anchored in tandem repeats (TRs) or segmental duplications (SDs). SVs called from aligned sequencing reads increase breakpoint disagreements by 2×-16×. Sequence accuracy had a minimal impact on breakpoints, but we observe a strong effect of ancestry. We confirm that SNP and indel polymorphisms are enriched at shifted breakpoints and are also absent from variant callsets. Breakpoint homology increases the likelihood of imprecise SV calls and the distance they are shifted, and tandem duplications are the most heavily affected SVs. Because graph genome methods normalize SV calls across samples, we investigated graphs generated by two different methods and find the resulting breakpoints are subject to other technical biases affecting breakpoint accuracy. The breakpoint inconsistencies we characterize affect ∼5% of the SVs called in a human genome and can impact variant interpretation and annotation. These limitations underscore a need for algorithm development to improve SV databases, mitigate the impact of ancestry on breakpoints, and increase the value of callsets for investigating breakpoint features.
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Affiliation(s)
- Peter A Audano
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032, USA
| | - Christine R Beck
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06032, USA;
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, Connecticut 06030, USA
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5
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Ganesh VS, Riquin K, Chatron N, Lamar KM, Aziz MC, Monin P, O’Leary M, Goodrich JK, Garimella KV, England E, Yoon E, Weisburd B, Aguet F, Bacino CA, Murdock DR, Dai H, Rosenfeld JA, Emrick LT, Ketkar S, Sarusi Y, Sanlaville D, Kayani S, Broadbent B, Isidor B, Pengam A, Cogné B, MacArthur DG, Ulitsky I, Carvill GL, O’Donnell-Luria A. Novel syndromic neurodevelopmental disorder caused by de novo deletion of CHASERR, a long noncoding RNA. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.31.24301497. [PMID: 38496558 PMCID: PMC10942497 DOI: 10.1101/2024.01.31.24301497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Genes encoding long non-coding RNAs (lncRNAs) comprise a large fraction of the human genome, yet haploinsufficiency of a lncRNA has not been shown to cause a Mendelian disease. CHASERR is a highly conserved human lncRNA adjacent to CHD2-a coding gene in which de novo loss-of-function variants cause developmental and epileptic encephalopathy. Here we report three unrelated individuals each harboring an ultra-rare heterozygous de novo deletion in the CHASERR locus. We report similarities in severe developmental delay, facial dysmorphisms, and cerebral dysmyelination in these individuals, distinguishing them from the phenotypic spectrum of CHD2 haploinsufficiency. We demonstrate reduced CHASERR mRNA expression and corresponding increased CHD2 mRNA and protein in whole blood and patient-derived cell lines-specifically increased expression of the CHD2 allele in cis with the CHASERR deletion, as predicted from a prior mouse model of Chaserr haploinsufficiency. We show for the first time that de novo structural variants facilitated by Alu-mediated non-allelic homologous recombination led to deletion of a non-coding element (the lncRNA CHASERR) to cause a rare syndromic neurodevelopmental disorder. We also demonstrate that CHD2 has bidirectional dosage sensitivity in human disease. This work highlights the need to carefully evaluate other lncRNAs, particularly those upstream of genes associated with Mendelian disorders.
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Affiliation(s)
- Vijay S. Ganesh
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Kevin Riquin
- Nantes Université, CHU de Nantes, CNRS, INSERM, L’institut du Thorax, Nantes, France
| | - Nicolas Chatron
- Institut Neuromyogène, Laboratoire Physiopathologie et Génétique du Neurone et du Muscle, Equipe Métabolisme énergétique et développement neuronal, CNRS UMR 5310, INSERM U1217, Université Lyon 1, Lyon, France
- Service de génétique, Hospices Civils de Lyon, Lyon, France
| | - Kay-Marie Lamar
- Departments of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Miriam C. Aziz
- Departments of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Pauline Monin
- Service de génétique, Hospices Civils de Lyon, Lyon, France
| | - Melanie O’Leary
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Julia K. Goodrich
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Kiran V. Garimella
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Eleina England
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Esther Yoon
- Departments of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Ben Weisburd
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Francois Aguet
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Carlos A. Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - David R. Murdock
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lisa T. Emrick
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shamika Ketkar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | - Yael Sarusi
- Departments of Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Damien Sanlaville
- Institut Neuromyogène, Laboratoire Physiopathologie et Génétique du Neurone et du Muscle, Equipe Métabolisme énergétique et développement neuronal, CNRS UMR 5310, INSERM U1217, Université Lyon 1, Lyon, France
- Service de génétique, Hospices Civils de Lyon, Lyon, France
| | - Saima Kayani
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Bertrand Isidor
- Nantes Université, CHU de Nantes, CNRS, INSERM, L’institut du Thorax, Nantes, France
- Nantes Université, CHU de Nantes, Service de Génétique médicale, F-44000 Nantes, France
| | - Alisée Pengam
- Nantes Université, CHU de Nantes, Service de Génétique médicale, F-44000 Nantes, France
| | - Benjamin Cogné
- Nantes Université, CHU de Nantes, CNRS, INSERM, L’institut du Thorax, Nantes, France
- Nantes Université, CHU de Nantes, Service de Génétique médicale, F-44000 Nantes, France
| | - Daniel G. MacArthur
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Centre for Population Genomics, Garvan Institute of Medical Research and UNSW Sydney, Sydney, Australia
- Centre for Population Genomics, Murdoch Children’s Research Institute, Melbourne, Australia
| | - Igor Ulitsky
- Departments of Biological Regulation and Molecular Neuroscience, Weizmann Institute of Science, Rehovot, Israel
| | - Gemma L. Carvill
- Departments of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Anne O’Donnell-Luria
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Division of Genetics and Genomics, Boston Children’s Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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6
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Lu X, Liu L. Genome stability from the perspective of telomere length. Trends Genet 2024; 40:175-186. [PMID: 37957036 DOI: 10.1016/j.tig.2023.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
Telomeres and their associated proteins protect the ends of chromosomes to maintain genome stability. Telomeres undergo progressive shortening with each cell division in mammalian somatic cells without telomerase, resulting in genome instability. When telomeres reach a critically short length or are recognized as a damage signal, cells enter a state of senescence, followed by cell cycle arrest, programmed cell death, or immortalization. This review provides an overview of recent advances in the intricate relationship between telomeres and genome instability. Alongside well-established mechanisms such as chromosomal fusion and telomere fusion, we will delve into the perspective on genome stability by examining the role of retrotransposons. Retrotransposons represent an emerging pathway to regulate genome stability through their interactions with telomeres.
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Affiliation(s)
- Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China.
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China; Frontiers Science Center for Cell Responses, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China; Haihe Laboratory of Cell Ecosystem, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China; Institute of Translational Medicine, Tianjin Union Medical Center, Nankai University, Tianjin 300000, China.
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7
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He Z, Chen O, Phillips N, Pasquesi GIM, Sabunciyan S, Florea L. Predicting Alu exonization in the human genome with a deep learning model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.03.574099. [PMID: 38260329 PMCID: PMC10802380 DOI: 10.1101/2024.01.03.574099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Alu exonization, or the recruitment of intronic Alu elements into gene sequences, has contributed to functional diversification; however, its extent and the ways in which it influences gene regulation are not fully understood. We developed an unbiased approach to predict Alu exonization events from genomic sequences implemented in a deep learning model, eXAlu, that overcomes the limitations of tissue or condition specificity and the computational burden of RNA-seq analysis. The model captures previously reported characteristics of exonized Alu sequences and can predict sequence elements important for Alu exonization. Using eXAlu, we estimate the number of Alu elements in the human genome undergoing exonization to be between 55-110K, 11-21 fold more than represented in the GENCODE gene database. Using RT-PCR we were able to validate selected predicted Alu exonization events, supporting the accuracy of our method. Lastly, we highlight a potential application of our method to identify polymorphic Alu insertion exonizations in individuals and in the population from whole genome sequencing data.
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Affiliation(s)
- Zitong He
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21205
| | - Ou Chen
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Noelani Phillips
- School of Kinesiology, University of Michigan, Ann Arbor, MI 48109
| | - Giulia Irene Maria Pasquesi
- BioFrontiers Institute and Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO 80309 and Crnic Institute Boulder Branch, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO 80303
| | - Sarven Sabunciyan
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Liliana Florea
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21205
- Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205
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8
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Brannan EO, Hartley GA, O’Neill RJ. Mechanisms of Rapid Karyotype Evolution in Mammals. Genes (Basel) 2023; 15:62. [PMID: 38254952 PMCID: PMC10815390 DOI: 10.3390/genes15010062] [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: 12/12/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Chromosome reshuffling events are often a foundational mechanism by which speciation can occur, giving rise to highly derivative karyotypes even amongst closely related species. Yet, the features that distinguish lineages prone to such rapid chromosome evolution from those that maintain stable karyotypes across evolutionary time are still to be defined. In this review, we summarize lineages prone to rapid karyotypic evolution in the context of Simpson's rates of evolution-tachytelic, horotelic, and bradytelic-and outline the mechanisms proposed to contribute to chromosome rearrangements, their fixation, and their potential impact on speciation events. Furthermore, we discuss relevant genomic features that underpin chromosome variation, including patterns of fusions/fissions, centromere positioning, and epigenetic marks such as DNA methylation. Finally, in the era of telomere-to-telomere genomics, we discuss the value of gapless genome resources to the future of research focused on the plasticity of highly rearranged karyotypes.
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Affiliation(s)
- Emry O. Brannan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (E.O.B.); (G.A.H.)
| | - Gabrielle A. Hartley
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (E.O.B.); (G.A.H.)
| | - Rachel J. O’Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; (E.O.B.); (G.A.H.)
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
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9
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Ibarra-Ramírez M, Campos-Acevedo LD, Martínez de Villarreal LE. Chromosomal Abnormalities of Interest in Turner Syndrome: An Update. J Pediatr Genet 2023; 12:263-272. [PMID: 38162151 PMCID: PMC10756729 DOI: 10.1055/s-0043-1770982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/01/2023] [Indexed: 01/03/2024]
Abstract
Turner syndrome (TS) is caused by the total or partial loss of the second sex chromosome; it occurs in 1 every 2,500-3,000 live births. The clinical phenotype is highly variable and includes short stature and gonadal dysgenesis. In 1959, the chromosomal origin of the syndrome was recognized; patients had 45 chromosomes with a single X chromosome. TS presents numerical and structural abnormalities in the sex chromosomes, interestingly only 40% have a 45, X karyotype. The rest of the chromosomal abnormalities include mosaics, deletions of the short and long arms of the X chromosome, rings, and isochromosomes. Despite multiple studies to establish a relationship between the clinical characteristics and the different chromosomal variants in TS, a clear association cannot yet be established. Currently, different mechanisms involved in the phenotype have been explored. This review focuses to analyze the different chromosomal abnormalities and phenotypes in TS and discusses the possible mechanisms that lead to these abnormalities.
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Affiliation(s)
- Marisol Ibarra-Ramírez
- Department of Genetics, “Dr. José Eleuterio González” University Hospital of the Autonomous University of Nuevo León, Monterrey, México
| | - Luis Daniel Campos-Acevedo
- Department of Genetics, “Dr. José Eleuterio González” University Hospital of the Autonomous University of Nuevo León, Monterrey, México
| | - Laura E. Martínez de Villarreal
- Department of Genetics, “Dr. José Eleuterio González” University Hospital of the Autonomous University of Nuevo León, Monterrey, México
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10
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Han M, Perkins MH, Novaes LS, Xu T, Chang H. Advances in transposable elements: from mechanisms to applications in mammalian genomics. Front Genet 2023; 14:1290146. [PMID: 38098473 PMCID: PMC10719622 DOI: 10.3389/fgene.2023.1290146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 11/13/2023] [Indexed: 12/17/2023] Open
Abstract
It has been 70 years since Barbara McClintock discovered transposable elements (TE), and the mechanistic studies and functional applications of transposable elements have been at the forefront of life science research. As an essential part of the genome, TEs have been discovered in most species of prokaryotes and eukaryotes, and the relative proportion of the total genetic sequence they comprise gradually increases with the expansion of the genome. In humans, TEs account for about 40% of the genome and are deeply involved in gene regulation, chromosome structure maintenance, inflammatory response, and the etiology of genetic and non-genetic diseases. In-depth functional studies of TEs in mammalian cells and the human body have led to a greater understanding of these fundamental biological processes. At the same time, as a potent mutagen and efficient genome editing tool, TEs have been transformed into biological tools critical for developing new techniques. By controlling the random insertion of TEs into the genome to change the phenotype in cells and model organisms, critical proteins of many diseases have been systematically identified. Exploiting the TE's highly efficient in vitro insertion activity has driven the development of cutting-edge sequencing technologies. Recently, a new technology combining CRISPR with TEs was reported, which provides a novel targeted insertion system to both academia and industry. We suggest that interrogating biological processes that generally depend on the actions of TEs with TEs-derived genetic tools is a very efficient strategy. For example, excessive activation of TEs is an essential factor in the occurrence of cancer in humans. As potent mutagens, TEs have also been used to unravel the key regulatory elements and mechanisms of carcinogenesis. Through this review, we aim to effectively combine the traditional views of TEs with recent research progress, systematically link the mechanistic discoveries of TEs with the technological developments of TE-based tools, and provide a comprehensive approach and understanding for researchers in different fields.
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Affiliation(s)
- Mei Han
- Guangzhou National Laboratory, Guangzhou, China
| | - Matthew H. Perkins
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Leonardo Santana Novaes
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Tao Xu
- Guangzhou National Laboratory, Guangzhou, China
| | - Hao Chang
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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11
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Luqman-Fatah A, Miyoshi T. Human LINE-1 retrotransposons: impacts on the genome and regulation by host factors. Genes Genet Syst 2023; 98:121-154. [PMID: 36436935 DOI: 10.1266/ggs.22-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Genome sequencing revealed that nearly half of the human genome is comprised of transposable elements. Although most of these elements have been rendered inactive due to mutations, full-length intact long interspersed element-1 (LINE-1 or L1) copies retain the ability to mobilize through RNA intermediates by a so-called "copy-and-paste" mechanism, termed retrotransposition. L1 is the only known autonomous mobile genetic element in the genome, and its retrotransposition contributes to inter- or intra-individual genetic variation within the human population. However, L1 retrotransposition also poses a threat to genome integrity due to gene disruption and chromosomal instability. Moreover, recent studies suggest that aberrant L1 expression can impact human health by causing diseases such as cancer and chronic inflammation that might lead to autoimmune disorders. To counteract these adverse effects, the host cells have evolved multiple layers of defense mechanisms at the epigenetic, RNA and protein levels. Intriguingly, several host factors have also been reported to facilitate L1 retrotransposition, suggesting that there is competition between negative and positive regulation of L1 by host factors. Here, we summarize the known host proteins that regulate L1 activity at different stages of the replication cycle and discuss how these factors modulate disease-associated phenotypes caused by L1.
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Affiliation(s)
- Ahmad Luqman-Fatah
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
| | - Tomoichiro Miyoshi
- Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University
- Department of Stress Response, Radiation Biology Center, Graduate School of Biostudies, Kyoto University
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12
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Pedini P, Laget L, Izard C, Menanteau C, Beley S, Granier T, Picard C, Bailly P, Chiaroni J, Mazieres S, Peyrard T, Silvy M. Identification of an Alu-mediated 5.7-kb deletion of the LU gene in a pregnant Moroccan woman with anti-Lu3. BLOOD TRANSFUSION = TRASFUSIONE DEL SANGUE 2023; 21:385-389. [PMID: 36346881 PMCID: PMC10497386 DOI: 10.2450/2022.0200-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Affiliation(s)
- Pascal Pedini
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Laurine Laget
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Caroline Izard
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Cécile Menanteau
- EFS Ile de France, Centre National de Référence pour les Groupes Sanguins (CNRGS), Paris, France
| | - Sophie Beley
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Thomas Granier
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Christophe Picard
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Pascal Bailly
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | - Jacques Chiaroni
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
| | | | - Thierry Peyrard
- EFS Ile de France, Centre National de Référence pour les Groupes Sanguins (CNRGS), Paris, France
- UMR_S1134, BIGR, Inserm, Université Paris Cité, Paris, France
| | - Monique Silvy
- EFS PACA-Corse, Marseille, France
- Aix Marseille Univ, CNRS, EFS, ADES, Marseille, France
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13
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Chen YJ, Wang MW, Qiu YS, Yuan RY, Wang N, Lin X, Chen WJ. Alu Retrotransposition Event in SPAST Gene as a Novel Cause of Hereditary Spastic Paraplegia. Mov Disord 2023; 38:1750-1755. [PMID: 37394769 DOI: 10.1002/mds.29522] [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: 01/31/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 07/04/2023] Open
Abstract
OBJECTIVES To diagnose the molecular cause of hereditary spastic paraplegia (HSP) observed in a four-generation family with autosomal dominant inheritance. METHODS Multiplex ligation-dependent probe amplification (MLPA), whole-exome sequencing (WES), and RNA sequencing (RNA-seq) of peripheral blood leukocytes were performed. Reverse transcription polymerase chain reaction (RT-PCR) and Sanger sequencing were used to characterize target regions of SPAST. RESULTS A 121-bp AluYb9 insertion with a 30-bp poly-A tail flanked by 15-bp direct repeats on both sides was identified in the edge of intron 16 in SPAST that segregated with the disease phenotype. CONCLUSIONS We identified an intronic AluYb9 insertion inducing splicing alteration in SPAST causing pure HSP phenotype that was not detected by routine WES analysis. Our findings suggest RNA-seq is a recommended implementation for undiagnosed cases by first-line diagnostic approaches. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Yi-Jun Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Geriatrics, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Department of Geriatrics, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Meng-Wen Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yu-Sen Qiu
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Ru-Ying Yuan
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Ning Wang
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Xiang Lin
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
| | - Wan-Jin Chen
- Department of Neurology and Institute of Neurology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Molecular Neurology, Fujian Medical University, Fuzhou, China
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14
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Maryami F, Davoudi-Dehaghani E, Khalesi N, Rismani E, Rahimi H, Talebi S, Zeinali S. Identification and characterization of the largest deletion in the PCCA gene causing severe acute early-onset form of propionic acidemia. Mol Genet Genomics 2023; 298:905-917. [PMID: 37131081 DOI: 10.1007/s00438-023-02023-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 04/16/2023] [Indexed: 05/04/2023]
Abstract
Whole-exome sequencing (WES) is an excellent method for the diagnosis of diseases of uncertain or heterogeneous genetic origin. However, it has limitations for detecting structural variations such as InDels, which the bioinformatics analyzers must be aware of. This study aimed at using WES to evaluate the genetic cause of the metabolic crisis in a 3-day-old neonate admitted to the neonatal intensive care unit (NICU) and deceased after a few days. Tandem mass spectrometry (MS/MS) showed a significant increase in propionyl carnitine (C3), proposing methylmalonic acidemia (MMA) or propionic acidemia (PA). WES demonstrated a homozygous missense variant in exon 4 of the BTD gene (NM_000060.4(BTD):c.1330G > C), responsible for partial biotinidase deficiency. Segregation analysis of the BTD variant revealed the homozygous status of the asymptomatic mother. Furthermore, observation of the bam file, around genes responsible for PA or MMA, by Integrative Genomics Viewer (IGV) software displayed a homozygous large deletion in the PCCA gene. Comprehensive confirmatory studies identified and segregated a novel outframe deletion of 217,877 bp length, "NG_008768.1:g.185211_403087delinsTA", extended from intron 11 to 21 of the PCCA, inducing a premature termination codon and activation of nonsense-mediated mRNA decay (NMD). Homology modeling of the mutant PCCA demonstrated eliminating the protein's active site and critical functional domains. Thereupon, this novel variant is suggested as the largest deletion in the PCCA gene, causing an acute early-onset PA. These results could expand the PCCA variants spectrum, and improve the existing knowledge on the molecular basis of PA, as well as provide new evidence of pathogenicity of the variant (NM_000060.4(BTD):c.1330G > C.
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Affiliation(s)
- Fereshteh Maryami
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur St., Tehran, Iran
| | - Elham Davoudi-Dehaghani
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur St., Tehran, Iran
| | - Nasrin Khalesi
- Department of Pediatrics and Neonatal Intensive Care Unit, Ali-Asghar Children's Hospital, Iran University of Medical Sciences, Shahid Vahid Dastgerdi Street, Modarres Highway, Tehran, Iran.
| | - Elham Rismani
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur St., Tehran, Iran
| | - Hamzeh Rahimi
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur St., Tehran, Iran
- Texas Biomedical Research Center, San Antonio, USA
| | - Saeed Talebi
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
- Department of Medical Genetics, Ali-Asghar Children's Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Sirous Zeinali
- Department of Molecular Medicine, Biotechnology Research Center, Pasteur Institute of Iran, Pasteur St., Tehran, Iran.
- Medical Genetics Lab, Kawsar Human Genetics Research Center, No. 41 Majlesi St., ValiAsr St., 1595645513, Tehran, Iran.
- Iranian Molecular Medicine Network, Pasteur Institute of Iran, Pasteur St, Tehran, Iran.
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15
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Audano PA, Beck CR. Small allelic variants are a source of ancestral bias in structural variant breakpoint placement. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.25.546295. [PMID: 37425850 PMCID: PMC10327140 DOI: 10.1101/2023.06.25.546295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
High-quality genome assemblies and sophisticated algorithms have increased sensitivity for a wide range of variant types, and breakpoint accuracy for structural variants (SVs, ≥ 50 bp) has improved to near basepair precision. Despite these advances, many SVs in unique regions of the genome are subject to systematic bias that affects breakpoint location. This ambiguity leads to less accurate variant comparisons across samples, and it obscures true breakpoint features needed for mechanistic inferences. To understand why SVs are not consistently placed, we reanalyzed 64 phased haplotypes constructed from long-read assemblies released by the Human Genome Structural Variation Consortium (HGSVC). We identified variable breakpoints for 882 SV insertions and 180 SV deletions not anchored in tandem repeats (TRs) or segmental duplications (SDs). While this is unexpectedly high for genome assemblies in unique loci, we find read-based callsets from the same sequencing data yielded 1,566 insertions and 986 deletions with inconsistent breakpoints also not anchored in TRs or SDs. When we investigated causes for breakpoint inaccuracy, we found sequence and assembly errors had minimal impact, but we observed a strong effect of ancestry. We confirmed that polymorphic mismatches and small indels are enriched at shifted breakpoints and that these polymorphisms are generally lost when breakpoints shift. Long tracts of homology, such as SVs mediated by transposable elements, increase the likelihood of imprecise SV calls and the distance they are shifted. Tandem Duplication (TD) breakpoints are the most heavily affected SV class with 14% of TDs placed at different locations across haplotypes. While graph genome methods normalize SV calls across many samples, the resulting breakpoints are sometimes incorrect, highlighting a need to tune graph methods for breakpoint accuracy. The breakpoint inconsistencies we characterize collectively affect ~5% of the SVs called in a human genome and underscore a need for algorithm development to improve SV databases, mitigate the impact of ancestry on breakpoint placement, and increase the value of callsets for investigating mutational processes.
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Affiliation(s)
- Peter A Audano
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Christine R Beck
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health Center, Farmington, CT, USA
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16
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Soejima M, Koda Y. Detection of c.375A>G, c.385A>T, c.571C>T, and sedel2 of FUT2 via Real-Time PCR in a Single Tube. Diagnostics (Basel) 2023; 13:2022. [PMID: 37370917 DOI: 10.3390/diagnostics13122022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/01/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
α(1,2)fucosyltransferase (Se enzyme) encoded by FUT2 is involved in the secretor status of ABH(O) blood group antigens. The sedel2 allele is one of the non-functional FUT2 (se) alleles in which 9.3 kb, containing the entire coding region of FUT2, is deleted by Alu-mediated nonhomologous recombination. In addition to this allele, three SNPs of FUT2, c.375A>G, c.385A>T, and c.571C>T, appear to be prevalent in certain Oceanian populations such as Polynesians. Recently, we developed an endpoint genotyping assay to determine sedel2 zygosity, using a FAM-labeled probe for detection of the sedel2 allele and a VIC-labeled probe for the detection of FUT2. In this study, instead of the VIC probe, a HEX-labeled probe covering both c.375A>G and c.385A>T and a Cy5-labeled probe covering c.571C>T were added to the sedel2 allele assay mixture to allow for the simultaneous detection of these four variations via endpoint genotyping for sedel2 zygosity and fluorescence melting curve analysis for c.375A>G, c.385A>T, and c.571C>T genotyping. The results obtained from 24 Samoan subjects using this method were identical to those obtained using previous methods. Therefore, it appears that the present method can accurately determine these four variations simultaneously.
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Affiliation(s)
- Mikiko Soejima
- Department of Forensic Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Yoshiro Koda
- Department of Forensic Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
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17
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Loboda AP, Adonin LS, Zvereva SD, Guschin DY, Korneenko TV, Telegina AV, Kondratieva OK, Frolova SE, Pestov NB, Barlev NA. BRCA Mutations-The Achilles Heel of Breast, Ovarian and Other Epithelial Cancers. Int J Mol Sci 2023; 24:ijms24054982. [PMID: 36902416 PMCID: PMC10003548 DOI: 10.3390/ijms24054982] [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: 02/11/2023] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Two related tumor suppressor genes, BRCA1 and BRCA2, attract a lot of attention from both fundamental and clinical points of view. Oncogenic hereditary mutations in these genes are firmly linked to the early onset of breast and ovarian cancers. However, the molecular mechanisms that drive extensive mutagenesis in these genes are not known. In this review, we hypothesize that one of the potential mechanisms behind this phenomenon can be mediated by Alu mobile genomic elements. Linking mutations in the BRCA1 and BRCA2 genes to the general mechanisms of genome stability and DNA repair is critical to ensure the rationalized choice of anti-cancer therapy. Accordingly, we review the literature available on the mechanisms of DNA damage repair where these proteins are involved, and how the inactivating mutations in these genes (BRCAness) can be exploited in anti-cancer therapy. We also discuss a hypothesis explaining why breast and ovarian epithelial tissues are preferentially susceptible to mutations in BRCA genes. Finally, we discuss prospective novel therapeutic approaches for treating BRCAness cancers.
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Affiliation(s)
- Anna P. Loboda
- Laboratory of Molecular Oncology, Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | | | - Svetlana D. Zvereva
- Laboratory of Molecular Oncology, Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Dmitri Y. Guschin
- School of Medicine, Nazarbayev University, Astana 010000, Kazakhstan
| | - Tatyana V. Korneenko
- Group of Cross-Linking Enzymes, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
| | | | | | | | - Nikolay B. Pestov
- Institute of Biomedical Chemistry, 119121 Moscow, Russia
- Group of Cross-Linking Enzymes, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products, 108819 Moscow, Russia
- Correspondence: (N.B.P.); (N.A.B.)
| | - Nick A. Barlev
- Institute of Biomedical Chemistry, 119121 Moscow, Russia
- School of Medicine, Nazarbayev University, Astana 010000, Kazakhstan
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products, 108819 Moscow, Russia
- Institute of Cytology, Tikhoretsky ave 4, 194064 St-Petersburg, Russia
- Correspondence: (N.B.P.); (N.A.B.)
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18
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Bai J, Qu Y, OuYang S, Jiao H, Wang Y, Li J, Huang W, Zhao Y, Peng X, Wang D, Jin Y, Wang H, Song F. Novel Alu-mediated deletions of the SMN1 gene were identified by ultra-long read sequencing technology in patients with spinal muscular atrophy. Neuromuscul Disord 2023; 33:382-390. [PMID: 37023488 DOI: 10.1016/j.nmd.2023.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/20/2023] [Accepted: 03/01/2023] [Indexed: 03/11/2023]
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by biallelic variants of the survival motor neuron 1 (SMN1) gene. In this study, our aim was to make a molecular diagnosis in two patients with SMA carrying only one SMN1 copy number. Using ultra-long read sequencing (Ultra-LRS), 1415 bp deletion and 3348 bp deletion of the SMN1 gene were identified in patient 1 and the father of patient 2, respectively. Ultra-LRS revealed two novel deletions, starting from the SMN1 promoter to intron 1. It also accurately provided the location of the deletion breakpoints in the SMN1 gene: chr5 g.70,924,798-70,926,212 for a 1415 bp deletion; chr5 g.70,922,695-70,926,042 for a 3348 bp deletion. By analyzing the breakpoint junctions, we identified that these genomic sequences were composed of Alu sequences, including AluJb, AluYm1, AluSq, and AluYm1, indicating that Alu-mediated rearrangements are a mechanism of SMN1 deletion events. In addition, full-length SMN1 transcripts and SMN protein in patient 1 were significantly decreased (p < 0.01), suggesting that a 1415 bp deletion that included the transcription and translation initiation sites of the SMN1 gene had severe consequences for SMN expression. Ultra-LRS can easily distinguish highly homozygous genes compared to other detection technologies, which is useful for detecting SMN1 intragenic mutations, to quickly discover structural rearrangements and to precisely present the breakpoint positions.
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19
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Trost H, Merkell A, Lopezcolorado FW, Stark J. Resolution of sequence divergence for repeat-mediated deletions shows a polarity that is mediated by MLH1. Nucleic Acids Res 2023; 51:650-667. [PMID: 36620890 PMCID: PMC9881173 DOI: 10.1093/nar/gkac1240] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/07/2022] [Accepted: 01/04/2023] [Indexed: 01/10/2023] Open
Abstract
Repeat-mediated deletions (RMDs) are a type of chromosomal rearrangement between two homologous sequences that causes loss of the sequence between the repeats, along with one of the repeats. Sequence divergence between repeats suppresses RMDs; the mechanisms of such suppression and of resolution of the sequence divergence remains poorly understood. We identified RMD regulators using a set of reporter assays in mouse cells that test two key parameters: repeat sequence divergence and the distances between one repeat and the initiating chromosomal break. We found that the mismatch repair factor MLH1 suppresses RMDs with sequence divergence in the same pathway as MSH2 and MSH6, and which is dependent on residues in MLH1 and its binding partner PMS2 that are important for nuclease activity. Additionally, we found that the resolution of sequence divergence in the RMD product has a specific polarity, where divergent bases that are proximal to the chromosomal break end are preferentially removed. Moreover, we found that the domain of MLH1 that forms part of the MLH1-PMS2 endonuclease is important for polarity of resolution of sequence divergence. We also identified distinctions between MLH1 versus TOP3α in regulation of RMDs. We suggest that MLH1 suppresses RMDs with sequence divergence, while also promoting directional resolution of sequence divergence in the RMD product.
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Affiliation(s)
- Hannah Trost
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
- Irell and Manella Graduate School of Biological Sciences, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | - Arianna Merkell
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
| | | | - Jeremy M Stark
- To whom correspondence should be addressed. Tel: +1 626 218-6346; Fax: +1 626 218 8892;
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20
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El Younsi M, Trabelsi M, Ben Youssef S, Ouertani I, Hammi Y, Achour A, Maazoul F, Kharrat M, Gargah T, M'rad R. Clinical and genetic characteristics of Tunisian children with infantile nephropathic cystinosis. Pediatr Nephrol 2023; 38:119-129. [PMID: 35445972 DOI: 10.1007/s00467-022-05525-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 02/25/2022] [Accepted: 02/25/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Nephropathic cystinosis is an autosomal recessive disease caused by a mutation in the CTNS gene which encodes cystinosin, a lysosomal cystine transporter. The spectrum of mutations in the CTNS gene is not well defined in the North African population. Here, we investigated twelve patients with nephropathic cystinosis belonging to eight Tunisian families in order to analyze the clinical and genetic characteristics of Tunisian children with infantile nephropathic cystinosis. METHODS Clinical data were collected retrospectively. Molecular analysis of the CTNS gene was performed by Sanger sequencing. RESULTS We describe a new splicing mutation c.971-1G > C in the homozygous state in 6/12 patients which seems to be a founder mutation. The reported deletion of 23nt c.771_793 Del (p.Gly258Serfs*30) was detected in a homozygous state in one patient and in a heterozygous compound state with the c.971-1G > C mutation in 3/12 patients. Two of 12 patients have a deletion of exons 4 and 5 of the CTNS gene. None of our patients had the most common 57-kb deletion. CONCLUSIONS The mutational spectrum in the Tunisian population is different from previously described populations. Thus, a molecular diagnostic strategy must be implemented in Tunisia, by targeting as a priority the common mutations described in this country. Such a strategy will allow a cost-effective diagnosis confirmation as well as early administration of treatment with oral cysteamine. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Mariem El Younsi
- Laboratoire de Génétique Humaine, LR99ES10, Faculté de Médecine de Tunis, Université de Tunis El Manar, 1007, Tunis, Tunisia
| | - Médiha Trabelsi
- Service des Maladies Congénitales et Héréditaires, Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Sandra Ben Youssef
- Service de Pédiatrie Néphrologique Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Inès Ouertani
- Service des Maladies Congénitales et Héréditaires, Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Yousra Hammi
- Service de Pédiatrie Néphrologique Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Ahlem Achour
- Service des Maladies Congénitales et Héréditaires, Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Faouzi Maazoul
- Service des Maladies Congénitales et Héréditaires, Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Maher Kharrat
- Laboratoire de Génétique Humaine, LR99ES10, Faculté de Médecine de Tunis, Université de Tunis El Manar, 1007, Tunis, Tunisia
| | - Tahar Gargah
- Service de Pédiatrie Néphrologique Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia
| | - Ridha M'rad
- Laboratoire de Génétique Humaine, LR99ES10, Faculté de Médecine de Tunis, Université de Tunis El Manar, 1007, Tunis, Tunisia. .,Service des Maladies Congénitales et Héréditaires, Hôpital Charles Nicolle, Bab Souika, 1006, Tunis, Tunisia.
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21
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Wang Q, Xiong F, Wu G, Liu W, Chen J, Wang B, Chen Y. Gene body methylation in cancer: molecular mechanisms and clinical applications. Clin Epigenetics 2022; 14:154. [PMID: 36443876 PMCID: PMC9706891 DOI: 10.1186/s13148-022-01382-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 11/18/2022] [Indexed: 11/29/2022] Open
Abstract
DNA methylation is an important epigenetic mechanism that regulates gene expression. To date, most DNA methylation studies have focussed on CpG islands in the gene promoter region, and the mechanism of methylation and the regulation of gene expression after methylation have been clearly elucidated. However, genome-wide methylation studies have shown that DNA methylation is widespread not only in promoters but also in gene bodies. Gene body methylation is widely involved in the expression regulation of many genes and is closely related to the occurrence and progression of malignant tumours. This review focusses on the formation of gene body methylation patterns, its regulation of transcription, and its relationship with tumours, providing clues to explore the mechanism of gene body methylation in regulating gene transcription and its significance and application in the field of oncology.
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Affiliation(s)
- Qi Wang
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Fei Xiong
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Guanhua Wu
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Wenzheng Liu
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Junsheng Chen
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Bing Wang
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
| | - Yongjun Chen
- grid.33199.310000 0004 0368 7223Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1095 Jiefang Road, Wuhan, 430074 Hubei Province China
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22
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Balachandran P, Walawalkar IA, Flores JI, Dayton JN, Audano PA, Beck CR. Transposable element-mediated rearrangements are prevalent in human genomes. Nat Commun 2022; 13:7115. [PMID: 36402840 PMCID: PMC9675761 DOI: 10.1038/s41467-022-34810-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/08/2022] [Indexed: 11/21/2022] Open
Abstract
Transposable elements constitute about half of human genomes, and their role in generating human variation through retrotransposition is broadly studied and appreciated. Structural variants mediated by transposons, which we call transposable element-mediated rearrangements (TEMRs), are less well studied, and the mechanisms leading to their formation as well as their broader impact on human diversity are poorly understood. Here, we identify 493 unique TEMRs across the genomes of three individuals. While homology directed repair is the dominant driver of TEMRs, our sequence-resolved TEMR resource allows us to identify complex inversion breakpoints, triplications or other high copy number polymorphisms, and additional complexities. TEMRs are enriched in genic loci and can create potentially important risk alleles such as a deletion in TRIM65, a known cancer biomarker and therapeutic target. These findings expand our understanding of this important class of structural variation, the mechanisms responsible for their formation, and establish them as an important driver of human diversity.
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Affiliation(s)
| | | | - Jacob I Flores
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Jacob N Dayton
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Peter A Audano
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Christine R Beck
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
- Department of Genetics and Genome Sciences, University of Connecticut Health Center, Farmington, CT, USA.
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA.
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23
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Paulat NS, McGuire E, Subramanian K, Osmanski AB, Moreno-Santillán DD, Ray DA, Xing J. Transposable Elements in Bats Show Differential Accumulation Patterns Determined by Class and Functionality. Life (Basel) 2022; 12:1190. [PMID: 36013369 PMCID: PMC9409754 DOI: 10.3390/life12081190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022] Open
Abstract
Bat genomes are characterized by a diverse transposable element (TE) repertoire. In particular, the genomes of members of the family Vespertilionidae contain both active retrotransposons and active DNA transposons. Each TE type is characterized by a distinct pattern of accumulation over the past ~40 million years. Each also exhibits its own target site preferences (sometimes shared with other TEs) that impact where they are likely to insert when mobilizing. Therefore, bats provide a great resource for understanding the diversity of TE insertion patterns. To gain insight into how these diverse TEs impact genome structure, we performed comparative spatial analyses between different TE classes and genomic features, including genic regions and CpG islands. Our results showed a depletion of all TEs in the coding sequence and revealed patterns of species- and element-specific attraction in the transcript. Trends of attraction in the distance tests also suggested significant TE activity in regions adjacent to genes. In particular, the enrichment of small, non-autonomous TE insertions in introns and near coding regions supports the hypothesis that the genomic distribution of TEs is the product of a balance of the TE insertion preference in open chromatin regions and the purifying selection against TEs within genes.
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Affiliation(s)
- Nicole S. Paulat
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Erin McGuire
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Krishnamurthy Subramanian
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Austin B. Osmanski
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | | | - David A. Ray
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA
| | - Jinchuan Xing
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
- Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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24
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Pascarella G, Hon CC, Hashimoto K, Busch A, Luginbühl J, Parr C, Hin Yip W, Abe K, Kratz A, Bonetti A, Agostini F, Severin J, Murayama S, Suzuki Y, Gustincich S, Frith M, Carninci P. Recombination of repeat elements generates somatic complexity in human genomes. Cell 2022; 185:3025-3040.e6. [DOI: 10.1016/j.cell.2022.06.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 03/30/2022] [Accepted: 06/16/2022] [Indexed: 12/14/2022]
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25
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Bhat A, Ghatage T, Bhan S, Lahane GP, Dhar A, Kumar R, Pandita RK, Bhat KM, Ramos KS, Pandita TK. Role of Transposable Elements in Genome Stability: Implications for Health and Disease. Int J Mol Sci 2022; 23:7802. [PMID: 35887150 PMCID: PMC9319628 DOI: 10.3390/ijms23147802] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/07/2022] [Accepted: 07/12/2022] [Indexed: 12/11/2022] Open
Abstract
Most living organisms have in their genome a sizable proportion of DNA sequences capable of mobilization; these sequences are commonly referred to as transposons, transposable elements (TEs), or jumping genes. Although long thought to have no biological significance, advances in DNA sequencing and analytical technologies have enabled precise characterization of TEs and confirmed their ubiquitous presence across all forms of life. These findings have ignited intense debates over their biological significance. The available evidence now supports the notion that TEs exert major influence over many biological aspects of organismal life. Transposable elements contribute significantly to the evolution of the genome by giving rise to genetic variations in both active and passive modes. Due to their intrinsic nature of mobility within the genome, TEs primarily cause gene disruption and large-scale genomic alterations including inversions, deletions, and duplications. Besides genomic instability, growing evidence also points to many physiologically important functions of TEs, such as gene regulation through cis-acting control elements and modulation of the transcriptome through epigenetic control. In this review, we discuss the latest evidence demonstrating the impact of TEs on genome stability and the underling mechanisms, including those developed to mitigate the deleterious impact of TEs on genomic stability and human health. We have also highlighted the potential therapeutic application of TEs.
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Affiliation(s)
- Audesh Bhat
- Centre for Molecular Biology, Central University of Jammu, Jammu 181143, India;
| | - Trupti Ghatage
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Sonali Bhan
- Centre for Molecular Biology, Central University of Jammu, Jammu 181143, India;
| | - Ganesh P. Lahane
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Arti Dhar
- Department of Pharmacy, BITS-Pilani Hyderabad Campus, Hyderabad 500078, India; (T.G.); (G.P.L.); (A.D.)
| | - Rakesh Kumar
- Department of Biotechnology, Shri Mata Vaishnav Devi University, Katra 182320, India;
| | - Raj K. Pandita
- Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
| | - Krishna M. Bhat
- Department of Molecular Medicine, University of South Florida, Tampa, FL 33612, USA;
| | - Kenneth S. Ramos
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX 77030, USA;
| | - Tej K. Pandita
- Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA;
- Center for Genomics and Precision Medicine, Texas A&M College of Medicine, Houston, TX 77030, USA;
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26
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Bai Y, Liu J, Xu J, Sun Y, Li J, Gao Y, Liu L, Jia C, Kong X, Wang L. Long-Read Sequencing Revealed Extragenic and Intragenic Duplications of Exons 56-61 in DMD in an Asymptomatic Male and a DMD Patient. Front Genet 2022; 13:878806. [PMID: 35615378 PMCID: PMC9125615 DOI: 10.3389/fgene.2022.878806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/31/2022] [Indexed: 11/13/2022] Open
Abstract
Expanded carrier screening (ECS) has become an increasingly common technique to assess the genetic risks of individuals in the prenatal or preconception period. Unexpected variants unrelated to referral are being increasingly detected in asymptomatic individuals through ECS. In this study, we reported an asymptomatic male with duplication of exons 56-61 in the DMD gene through ECS using whole-exome sequencing (WES), which was also detected in a male patient diagnosed with typical Duchenne muscular dystrophy (DMD). Breakpoint analysis was then performed to explore the potential mechanisms of phenotypic differences using long-read sequencing (LRS), PacBio single-molecule real-time (PacBio SMRT) target sequencing, and Sanger sequencing. Complex structural variations (SVs) on chromosome X were identified in the asymptomatic male, which revealed that the duplication occurred outside the DMD gene; whereas, the duplication in the patient with DMD was a tandem repeat. The phenotypic differences between the two men could be explained by the different breakpoint junctions. To the best of our knowledge, this is the first report of a breakpoint analysis of DMD duplication in two men with different phenotypes. Breakpoint analysis is necessary when the clinical phenotypes are inconsistent with genotypes, and it applies to prenatal testing.
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Affiliation(s)
- Ying Bai
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ju Liu
- Department of Neurology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinghan Xu
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yue Sun
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jingjing Li
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yong Gao
- GrandOmics Biosciences, Beijing, China
| | - Lina Liu
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | | | - Xiangdong Kong
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Li Wang
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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27
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Pinto A, Cunha C, Chaves R, Butchbach MER, Adega F. Comprehensive In Silico Analysis of Retrotransposon Insertions within the Survival Motor Neuron Genes Involved in Spinal Muscular Atrophy. BIOLOGY 2022; 11:824. [PMID: 35741345 PMCID: PMC9219815 DOI: 10.3390/biology11060824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/19/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022]
Abstract
Transposable elements (TEs) are interspersed repetitive and mobile DNA sequences within the genome. Better tools for evaluating TE-derived sequences have provided insights into the contribution of TEs to human development and disease. Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease that is caused by deletions or mutations in the Survival Motor Neuron 1 (SMN1) gene but retention of its nearly perfect orthologue SMN2. Both genes are highly enriched in TEs. To establish a link between TEs and SMA, we conducted a comprehensive, in silico analysis of TE insertions within the SMN1/2 loci of SMA, carrier and healthy genomes. We found an Alu insertion in the promoter region and one L1 element in the 3'UTR that may play an important role in alternative promoter as well as in alternative transcriptional termination. Additionally, several intronic Alu repeats may influence alternative splicing via RNA circularization and causes the presence of new alternative exons. These Alu repeats present throughout the genes are also prone to recombination events that could lead to SMN1 exons deletions and, ultimately, SMA. TE characterization of the SMA genomic region could provide for a better understanding of the implications of TEs on human disease and genomic evolution.
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Affiliation(s)
- Albano Pinto
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Catarina Cunha
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Raquel Chaves
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
| | - Matthew E. R. Butchbach
- Division of Neurology, Nemours Children’s Hospital Delaware, Wilmington, DE 19803, USA;
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Filomena Adega
- Laboratory of Cytogenomics and Animal Genomics (CAG), Department of Genetics and Biotechnology (DGB), University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal; (A.P.); (C.C.); (R.C.)
- BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisbon, Portugal
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28
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Chesnokova E, Beletskiy A, Kolosov P. The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:5847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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Affiliation(s)
- Ekaterina Chesnokova
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, 117485 Moscow, Russia; (A.B.); (P.K.)
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29
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Abstract
In human cells, each rDNA unit consists of the ~13 kb long ribosomal part and ~30 kb long intergenic spacer (IGS). The ribosomal part, transcribed by RNA polymerase I (pol I), includes genes coding for 18S, 5.8S, and 28S RNAs of the ribosomal particles, as well as their four transcribed spacers. Being highly repetitive, intensively transcribed, and abundantly methylated, rDNA is a very fragile site of the genome, with high risk of instability leading to cancer. Multiple small mutations, considerable expansion or contraction of the rDNA locus, and abnormally enhanced pol I transcription are usual symptoms of transformation. Recently it was found that both IGS and the ribosomal part of the locus contain many functional/potentially functional regions producing non-coding RNAs, which participate in the pol I activity regulation, stress reactions, and development of the malignant phenotype. Thus, there are solid reasons to believe that rDNA locus plays crucial role in carcinogenesis. In this review we discuss the data concerning the human rDNA and its closely associated factors as both targets and drivers of the pathways essential for carcinogenesis. We also examine whether variability in the structure of the locus may be blamed for the malignant transformation. Additionally, we consider the prospects of therapy focused on the activity of rDNA.
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30
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Soejima M, Koda Y. Real-time PCR-based detection of the Alu-mediated deletion of FUT2 (se del2). Leg Med (Tokyo) 2021; 54:101986. [PMID: 34736142 DOI: 10.1016/j.legalmed.2021.101986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/16/2021] [Accepted: 10/25/2021] [Indexed: 10/19/2022]
Abstract
Secretor status of the ABH(O) histoblood group antigens is regulated by secretor type α(1,2)fucosyltransferase encoded by FUT2. The sedel2 allele is a complete deletion of the FUT2 coding region generated by Alu-mediated homologous recombination. This deletion seems to be exclusively encountered in certain Oceanian populations. From the perspective of forensic science, sedel2 is considered to be one of ancestry informative markers for these populations. Real-time PCR followed by melting curve analysis was employed to find primer set to specifically amplify sedel2. We designed primers which produced a 231-bp amplicon specific to sedel2. The specificity of these primers was also confirmed by gel electrophoresis and sequencing of the PCR product. Then, two real-time PCR methods based on melting curve analysis and a hydrolysis probe were designed to determine sedel2 zygosity by adding FUT2-specific primers. These two methods were validated by analyzing 24 Samoan subjects. The results obtained from 24 Samoan subjects by the two methods were fully in accordance with those obtained by a previous conventional PCR method that amplified a 2.7-kb fragment of sedel2. Therefore, these two methods seemed to accurately determine the zygosity of sedel2 and were useful for investigation of the distribution and origin of this deletion.
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Affiliation(s)
- Mikiko Soejima
- Department of Forensic Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Yoshiro Koda
- Department of Forensic Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan.
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31
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Butchbach MER. Genomic Variability in the Survival Motor Neuron Genes ( SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development. Int J Mol Sci 2021; 22:ijms22157896. [PMID: 34360669 PMCID: PMC8348669 DOI: 10.3390/ijms22157896] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/14/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.
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Affiliation(s)
- Matthew E. R. Butchbach
- Center for Applied Clinical Genomics, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA;
- Center for Pediatric Research, Nemours Children’s Health Delaware, Wilmington, DE 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA 19107, USA
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32
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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33
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Almojil D, Bourgeois Y, Falis M, Hariyani I, Wilcox J, Boissinot S. The Structural, Functional and Evolutionary Impact of Transposable Elements in Eukaryotes. Genes (Basel) 2021; 12:genes12060918. [PMID: 34203645 PMCID: PMC8232201 DOI: 10.3390/genes12060918] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
Transposable elements (TEs) are nearly ubiquitous in eukaryotes. The increase in genomic data, as well as progress in genome annotation and molecular biology techniques, have revealed the vast number of ways mobile elements have impacted the evolution of eukaryotes. In addition to being the main cause of difference in haploid genome size, TEs have affected the overall organization of genomes by accumulating preferentially in some genomic regions, by causing structural rearrangements or by modifying the recombination rate. Although the vast majority of insertions is neutral or deleterious, TEs have been an important source of evolutionary novelties and have played a determinant role in the evolution of fundamental biological processes. TEs have been recruited in the regulation of host genes and are implicated in the evolution of regulatory networks. They have also served as a source of protein-coding sequences or even entire genes. The impact of TEs on eukaryotic evolution is only now being fully appreciated and the role they may play in a number of biological processes, such as speciation and adaptation, remains to be deciphered.
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Affiliation(s)
- Dareen Almojil
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Yann Bourgeois
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK;
| | - Marcin Falis
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Imtiyaz Hariyani
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
| | - Justin Wilcox
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates
| | - Stéphane Boissinot
- New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates; (D.A.); (M.F.); (I.H.); (J.W.)
- Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi P.O. Box 129188, United Arab Emirates
- Correspondence:
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34
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Pappalardo XG, Barra V. Losing DNA methylation at repetitive elements and breaking bad. Epigenetics Chromatin 2021; 14:25. [PMID: 34082816 PMCID: PMC8173753 DOI: 10.1186/s13072-021-00400-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 05/21/2021] [Indexed: 02/08/2023] Open
Abstract
Background DNA methylation is an epigenetic chromatin mark that allows heterochromatin formation and gene silencing. It has a fundamental role in preserving genome stability (including chromosome stability) by controlling both gene expression and chromatin structure. Therefore, the onset of an incorrect pattern of DNA methylation is potentially dangerous for the cells. This is particularly important with respect to repetitive elements, which constitute the third of the human genome. Main body Repetitive sequences are involved in several cell processes, however, due to their intrinsic nature, they can be a source of genome instability. Thus, most repetitive elements are usually methylated to maintain a heterochromatic, repressed state. Notably, there is increasing evidence showing that repetitive elements (satellites, long interspersed nuclear elements (LINEs), Alus) are frequently hypomethylated in various of human pathologies, from cancer to psychiatric disorders. Repetitive sequences’ hypomethylation correlates with chromatin relaxation and unscheduled transcription. If these alterations are directly involved in human diseases aetiology and how, is still under investigation. Conclusions Hypomethylation of different families of repetitive sequences is recurrent in many different human diseases, suggesting that the methylation status of these elements can be involved in preservation of human health. This provides a promising point of view towards the research of therapeutic strategies focused on specifically tuning DNA methylation of DNA repeats.
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Affiliation(s)
- Xena Giada Pappalardo
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), University of Catania, 95125, Catania, Italy.,National Council of Research, Institute for Biomedical Research and Innovation (IRIB), Unit of Catania, 95125, Catania, Italy
| | - Viviana Barra
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128, Palermo, Italy.
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35
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Bergero R, Ellis P, Haerty W, Larcombe L, Macaulay I, Mehta T, Mogensen M, Murray D, Nash W, Neale MJ, O'Connor R, Ottolini C, Peel N, Ramsey L, Skinner B, Suh A, Summers M, Sun Y, Tidy A, Rahbari R, Rathje C, Immler S. Meiosis and beyond - understanding the mechanistic and evolutionary processes shaping the germline genome. Biol Rev Camb Philos Soc 2021; 96:822-841. [PMID: 33615674 PMCID: PMC8246768 DOI: 10.1111/brv.12680] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/15/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022]
Abstract
The separation of germ cell populations from the soma is part of the evolutionary transition to multicellularity. Only genetic information present in the germ cells will be inherited by future generations, and any molecular processes affecting the germline genome are therefore likely to be passed on. Despite its prevalence across taxonomic kingdoms, we are only starting to understand details of the underlying micro-evolutionary processes occurring at the germline genome level. These include segregation, recombination, mutation and selection and can occur at any stage during germline differentiation and mitotic germline proliferation to meiosis and post-meiotic gamete maturation. Selection acting on germ cells at any stage from the diploid germ cell to the haploid gametes may cause significant deviations from Mendelian inheritance and may be more widespread than previously assumed. The mechanisms that affect and potentially alter the genomic sequence and allele frequencies in the germline are pivotal to our understanding of heritability. With the rise of new sequencing technologies, we are now able to address some of these unanswered questions. In this review, we comment on the most recent developments in this field and identify current gaps in our knowledge.
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Affiliation(s)
- Roberta Bergero
- Institute of Evolutionary BiologyUniversity of EdinburghEdinburghEH9 3JTU.K.
| | - Peter Ellis
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
| | | | - Lee Larcombe
- Applied Exomics LtdStevenage Bioscience CatalystStevenageSG1 2FXU.K.
| | - Iain Macaulay
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Tarang Mehta
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Mette Mogensen
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
| | - David Murray
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
| | - Will Nash
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Matthew J. Neale
- Genome Damage and Stability Centre, School of Life SciencesUniversity of SussexBrightonBN1 9RHU.K.
| | | | | | - Ned Peel
- Earlham InstituteNorwich Research ParkNorwichNR4 7UZU.K.
| | - Luke Ramsey
- The James Hutton InstituteInvergowrieDundeeDD2 5DAU.K.
| | - Ben Skinner
- School of Life SciencesUniversity of EssexColchesterCO4 3SQU.K.
| | - Alexander Suh
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
- Department of Organismal BiologyUppsala UniversityNorbyvägen 18DUppsala752 36Sweden
| | - Michael Summers
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
- The Bridge Centre1 St Thomas Street, London BridgeLondonSE1 9RYU.K.
| | - Yu Sun
- Norwich Medical SchoolUniversity of East AngliaNorwich Research Park, Colney LnNorwichNR4 7UGU.K.
| | - Alison Tidy
- School of BiosciencesUniversity of Nottingham, Plant Science, Sutton Bonington CampusSutton BoningtonLE12 5RDU.K.
| | | | - Claudia Rathje
- School of BiosciencesUniversity of KentCanterburyCT2 7NJU.K.
| | - Simone Immler
- School of Biological SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJU.K.
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36
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Ferrari R, Grandi N, Tramontano E, Dieci G. Retrotransposons as Drivers of Mammalian Brain Evolution. Life (Basel) 2021; 11:life11050376. [PMID: 33922141 PMCID: PMC8143547 DOI: 10.3390/life11050376] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Retrotransposons, a large and diverse class of transposable elements that are still active in humans, represent a remarkable force of genomic innovation underlying mammalian evolution. Among the features distinguishing mammals from all other vertebrates, the presence of a neocortex with a peculiar neuronal organization, composition and connectivity is perhaps the one that, by affecting the cognitive abilities of mammals, contributed mostly to their evolutionary success. Among mammals, hominids and especially humans display an extraordinarily expanded cortical volume, an enrichment of the repertoire of neural cell types and more elaborate patterns of neuronal connectivity. Retrotransposon-derived sequences have recently been implicated in multiple layers of gene regulation in the brain, from transcriptional and post-transcriptional control to both local and large-scale three-dimensional chromatin organization. Accordingly, an increasing variety of neurodevelopmental and neurodegenerative conditions are being recognized to be associated with retrotransposon dysregulation. We review here a large body of recent studies lending support to the idea that retrotransposon-dependent evolutionary novelties were crucial for the emergence of mammalian, primate and human peculiarities of brain morphology and function.
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Affiliation(s)
- Roberto Ferrari
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
| | - Nicole Grandi
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
| | - Enzo Tramontano
- Laboratory of Molecular Virology, Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy; (N.G.); (E.T.)
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale delle Ricerche, 09042 Monserrato, Italy
| | - Giorgio Dieci
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
- Correspondence:
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37
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Pócza T, Grolmusz VK, Papp J, Butz H, Patócs A, Bozsik A. Germline Structural Variations in Cancer Predisposition Genes. Front Genet 2021; 12:634217. [PMID: 33936164 PMCID: PMC8081352 DOI: 10.3389/fgene.2021.634217] [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: 11/27/2020] [Accepted: 03/08/2021] [Indexed: 12/14/2022] Open
Abstract
In addition to single nucleotide variations and small-scale indels, structural variations (SVs) also contribute to the genetic diversity of the genome. SVs, such as deletions, duplications, amplifications, or inversions may also affect coding regions of cancer-predisposing genes. These rearrangements may abrogate the open reading frame of these genes or adversely affect their expression and may thus act as germline mutations in hereditary cancer syndromes. With the capacity of disrupting the function of tumor suppressors, structural variations confer an increased risk of cancer and account for a remarkable fraction of heritability. The development of sequencing techniques enables the discovery of a constantly growing number of SVs of various types in cancer predisposition genes (CPGs). Here, we provide a comprehensive review of the landscape of germline SV types, detection methods, pathomechanisms, and frequency in CPGs, focusing on the two most common cancer syndromes: hereditary breast- and ovarian cancer and gastrointestinal cancers. Current knowledge about the possible molecular mechanisms driving to SVs is also summarized.
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Affiliation(s)
- Tímea Pócza
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary
| | - Vince Kornél Grolmusz
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - János Papp
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
| | - Henriett Butz
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary.,Department of Laboratory Medicine, Semmelweis University, Budapest, Hungary
| | - Attila Patócs
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary.,Department of Laboratory Medicine, Semmelweis University, Budapest, Hungary
| | - Anikó Bozsik
- Department of Molecular Genetics, National Institute of Oncology, Budapest, Hungary.,Hereditary Cancers Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
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38
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A study of transposable element-associated structural variations (TASVs) using a de novo-assembled Korean genome. Exp Mol Med 2021; 53:615-630. [PMID: 33833373 PMCID: PMC8102501 DOI: 10.1038/s12276-021-00586-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
Advances in next-generation sequencing (NGS) technology have made personal genome sequencing possible, and indeed, many individual human genomes have now been sequenced. Comparisons of these individual genomes have revealed substantial genomic differences between human populations as well as between individuals from closely related ethnic groups. Transposable elements (TEs) are known to be one of the major sources of these variations and act through various mechanisms, including de novo insertion, insertion-mediated deletion, and TE–TE recombination-mediated deletion. In this study, we carried out de novo whole-genome sequencing of one Korean individual (KPGP9) via multiple insert-size libraries. The de novo whole-genome assembly resulted in 31,305 scaffolds with a scaffold N50 size of 13.23 Mb. Furthermore, through computational data analysis and experimental verification, we revealed that 182 TE-associated structural variation (TASV) insertions and 89 TASV deletions contributed 64,232 bp in sequence gain and 82,772 bp in sequence loss, respectively, in the KPGP9 genome relative to the hg19 reference genome. We also verified structural differences associated with TASVs by comparative analysis with TASVs in recent genomes (AK1 and TCGA genomes) and reported their details. Here, we constructed a new Korean de novo whole-genome assembly and provide the first study, to our knowledge, focused on the identification of TASVs in an individual Korean genome. Our findings again highlight the role of TEs as a major driver of structural variations in human individual genomes. A novel strategy for genome analysis offers insights into the distribution and impact on genome variation of transposable elements, DNA sequences that can replicate and relocate themselves at different chromosomal regions. These sequences, also known as ‘jumping genes’, comprise up to 50% of the genome, but it has proven challenging to map them with existing techniques. Seyoung Mun of Dankook University, Cheonan, South Korea, and coworkers have developed a sequencing and computational analysis strategy that allowed them to accurately map transposable elements across the genome of a Korean individual. These data revealed hundreds of insertion and deletion events relative to an existing reference map of the genome, showing significant alterations in the chromosomal structure. The authors speculate that such widespread transposition events could potentially contribute to individual differences in gene expression and risk of disease.
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39
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Long X, Xue H. Genetic-variant hotspots and hotspot clusters in the human genome facilitating adaptation while increasing instability. Hum Genomics 2021; 15:19. [PMID: 33741065 PMCID: PMC7976700 DOI: 10.1186/s40246-021-00318-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 03/04/2021] [Indexed: 12/25/2022] Open
Abstract
Background Genetic variants, underlining phenotypic diversity, are known to distribute unevenly in the human genome. A comprehensive understanding of the distributions of different genetic variants is important for insights into genetic functions and disorders. Methods Herein, a sliding-window scan of regional densities of eight kinds of germline genetic variants, including single-nucleotide-polymorphisms (SNPs) and four size-classes of copy-number-variations (CNVs) in the human genome has been performed. Results The study has identified 44,379 hotspots with high genetic-variant densities, and 1135 hotspot clusters comprising more than one type of hotspots, accounting for 3.1% and 0.2% of the genome respectively. The hotspots and clusters are found to co-localize with different functional genomic features, as exemplified by the associations of hotspots of middle-size CNVs with histone-modification sites, work with balancing and positive selections to meet the need for diversity in immune proteins, and facilitate the development of sensory-perception and neuroactive ligand-receptor interaction pathways in the function-sparse late-replicating genomic sequences. Genetic variants of different lengths co-localize with retrotransposons of different ages on a “long-with-young” and “short-with-all” basis. Hotspots and clusters are highly associated with tumor suppressor genes and oncogenes (p < 10−10), and enriched with somatic tumor CNVs and the trait- and disease-associated SNPs identified by genome-wise association studies, exceeding tenfold enrichment in clusters comprising SNPs and extra-long CNVs. Conclusions In conclusion, the genetic-variant hotspots and clusters represent two-edged swords that spearhead both positive and negative genomic changes. Their strong associations with complex traits and diseases also open up a potential “Common Disease-Hotspot Variant” approach to the missing heritability problem. Supplementary Information The online version contains supplementary material available at 10.1186/s40246-021-00318-3.
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Affiliation(s)
- Xi Long
- Division of Life Science and Applied Genomics Centre, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.,HKUST Shenzhen Research Institute, 9 Yuexing First Road, Nanshan, Shenzhen, China
| | - Hong Xue
- Division of Life Science and Applied Genomics Centre, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China. .,HKUST Shenzhen Research Institute, 9 Yuexing First Road, Nanshan, Shenzhen, China. .,Centre for Cancer Genomics, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China.
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40
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Morales ME, Kaul T, Walker J, Everett C, White T, Deininger P. Altered DNA repair creates novel Alu/Alu repeat-mediated deletions. Hum Mutat 2021; 42:600-613. [PMID: 33675284 PMCID: PMC8068675 DOI: 10.1002/humu.24193] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 01/25/2021] [Accepted: 02/24/2021] [Indexed: 12/21/2022]
Abstract
Alu elements are the most abundant source of nonallelic homology that influences genetic instability in the human genome. When there is a DNA double-stranded break, the Alu element's high copy number, moderate length and distance and mismatch between elements uniquely influence recombination processes. We utilize a reporter-gene assay to show the complex influence of Alu mismatches on Alu-related repeat-mediated deletions (RMDs). The Alu/Alu heteroduplex intermediate can result in a nonallelic homologous recombination (HR). Alternatively, the heteroduplex can result in various DNA breaks around the Alu elements caused by competing nucleases. These breaks can undergo Alt-nonhomologous end joining to cause deletions focused around the Alu elements. Formation of these heteroduplex intermediates is largely RAD52 dependent. Cells with low ERCC1 levels utilize more of these alternatives resolutions, while cells with MSH2 defects tend to have more RMDs with a specific increase in the HR events. Therefore, Alu elements are expected to create different forms of deletions in various cancers depending on a number of these DNA repair defects.
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Affiliation(s)
- Maria E Morales
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Tiffany Kaul
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - JaNiece Walker
- Department of Biology, Xavier University, New Orleans, Louisiana, USA
| | - Chelsea Everett
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA
| | - Travis White
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Prescott Deininger
- Tulane Cancer Center, Tulane University, New Orleans, Louisiana, USA.,Department of Epidemiology, Tulane University, New Orleans, Louisiana, USA
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41
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van den Akker J, Hon L, Ondov A, Mahkovec Z, O'Connor R, Chan RC, Lock J, Zimmer AD, Rostamianfar A, Ginsberg J, Leon A, Topper S. Intronic Breakpoint Signatures Enhance Detection and Characterization of Clinically Relevant Germline Structural Variants. J Mol Diagn 2021; 23:612-629. [PMID: 33621668 DOI: 10.1016/j.jmoldx.2021.01.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/14/2020] [Accepted: 01/27/2021] [Indexed: 12/16/2022] Open
Abstract
The relevance of large copy number variants (CNVs) to hereditary disorders has been long recognized, and population sequencing efforts have chronicled many common structural variants (SVs). However, limited data are available on the clinical contribution of rare germline SVs. Here, a detailed characterization of SVs identified using targeted next-generation sequencing was performed. Across 50 genes associated with hereditary cancer and cardiovascular disorders, a minimum of 828 unique SVs were reported, including 584 fully characterized SVs. Almost 40% of CNVs were <5 kb, with one in three deletions impacting a single exon. Additionally, 36 mid-range deletions/duplications (50 to 250 bp), 21 mobile element insertions, 6 inversions, and 27 complex rearrangements were detected. This data set was used to model SV detection in a bioinformatics pipeline solely relying on read depth, which revealed that genome sequencing (30×) allows detection of 71%, a 500× panel only targeting coding regions 53%, and exome sequencing (100×) <20% of characterized SVs. SVs accounted for 14.1% of all unique pathogenic variants, supporting the importance of SVs in hereditary disorders. Robust SV detection requires an ensemble of variant-calling algorithms that utilize sequencing of intronic regions. These algorithms should use distinct data features representative of each class of mutational mechanism, including recombination between two sequences sharing high similarity, covariants inserted between CNV breakpoints, and complex rearrangements containing inverted sequences.
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42
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Ali A, Han K, Liang P. Role of Transposable Elements in Gene Regulation in the Human Genome. Life (Basel) 2021; 11:118. [PMID: 33557056 PMCID: PMC7913837 DOI: 10.3390/life11020118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 01/28/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs), also known as mobile elements (MEs), are interspersed repeats that constitute a major fraction of the genomes of higher organisms. As one of their important functional impacts on gene function and genome evolution, TEs participate in regulating the expression of genes nearby and even far away at transcriptional and post-transcriptional levels. There are two known principal ways by which TEs regulate the expression of genes. First, TEs provide cis-regulatory sequences in the genome with their intrinsic regulatory properties for their own expression, making them potential factors for regulating the expression of the host genes. TE-derived cis-regulatory sites are found in promoter and enhancer elements, providing binding sites for a wide range of trans-acting factors. Second, TEs encode for regulatory RNAs with their sequences showed to be present in a substantial fraction of miRNAs and long non-coding RNAs (lncRNAs), indicating the TE origin of these RNAs. Furthermore, TEs sequences were found to be critical for regulatory functions of these RNAs, including binding to the target mRNA. TEs thus provide crucial regulatory roles by being part of cis-regulatory and regulatory RNA sequences. Moreover, both TE-derived cis-regulatory sequences and TE-derived regulatory RNAs have been implicated in providing evolutionary novelty to gene regulation. These TE-derived regulatory mechanisms also tend to function in a tissue-specific fashion. In this review, we aim to comprehensively cover the studies regarding these two aspects of TE-mediated gene regulation, mainly focusing on the mechanisms, contribution of different types of TEs, differential roles among tissue types, and lineage-specificity, based on data mostly in humans.
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Affiliation(s)
- Arsala Ali
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada;
| | - Kyudong Han
- Department of Microbiology, Dankook University, Cheonan 31116, Korea;
- Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, Korea
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada;
- Centre of Biotechnologies, Brock University, St. Catharines, ON L2S 3A1, Canada
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43
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Li L, Jia C, Tang Y, Kong Y, Xia Y, Ma L. Novel Gross Deletion Mutations in NTRK1 Gene Associated With Congenital Insensitivity to Pain With Anhidrosis. Front Pediatr 2021; 9:638190. [PMID: 33748046 PMCID: PMC7969531 DOI: 10.3389/fped.2021.638190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 01/20/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare inherited autosomal recessive disorder characterized by insensitivity to noxious stimuli, anhidrosis, recurrent fever, and intellectual disability. CIPA is mainly caused by mutations in the neurotrophic tyrosine kinase receptor type 1 gene (NTRK1). This study aims to identify pathogenic mutations underlying CIPA in two unrelated Chinese families. Methods: DNA was extracted from blood samples of patients and their available family members and subjected to whole exome sequencing (WES). Real-time PCR (qPCR), Gap-PCR, and Sanger sequencing were applied to verify the identified variants. Result: We found novel compound gross deletion mutations [exon1-6 del (g.1-1258_10169del); exon5-7 del (g.6995_11999del)] of NTRK1 (MIM 191315) gene in family 1 and the compound heterozygous mutations [c.851-33T>A; exon5-7 del (g.6995_11999del)] in family 2. Interestingly, we discovered the intragenic novel gross deletion [exon5-7 del (g.6995_11999del)] mediated by recombination between Alu elements. Conclusions: The present study highlights two rare gross deletion mutations in the NTRK1 gene associated with CIPA in two unrelated Chinese families. The deletion of exon1-6 (g.1-1258_10169del) is thought to be the largest NTRK1 deletion reported to date. Our findings expand the mutation spectrum of NTRK1 mutations in the Chinese and could be useful for prenatal interventions and more precise pharmacological treatments to patients. WES conducted in our study is a convenient and useful tool for clinical diagnosis of CIPA and other associated disorders.
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Affiliation(s)
- Lulu Li
- Department of Newborn Screening Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Chao Jia
- Department of Neonatology, Hebei Provincial Children's Hospital, Shijiazhuang, China
| | - Yue Tang
- Department of Newborn Screening Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Yuanyuan Kong
- Department of Newborn Screening Center, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, China
| | - Yaofang Xia
- Department of Neonatology, Hebei Provincial Children's Hospital, Shijiazhuang, China
| | - Li Ma
- Department of Neonatology, Hebei Provincial Children's Hospital, Shijiazhuang, China
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44
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Pan YQ, Xing L. The Current View on the Helicase Activity of RNA Helicase A and Its Role in Gene Expression. Curr Protein Pept Sci 2020; 22:29-40. [PMID: 33143622 DOI: 10.2174/1389203721666201103084122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 08/18/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
RNA helicase A (RHA) is a DExH-box helicase that plays regulatory roles in a variety of cellular processes, including transcription, translation, RNA splicing, editing, transport, and processing, microRNA genesis and maintenance of genomic stability. It is involved in virus replication, oncogenesis, and innate immune response. RHA can unwind nucleic acid duplex by nucleoside triphosphate hydrolysis. The insight into the molecular mechanism of helicase activity is fundamental to understanding the role of RHA in the cell. Herein, we reviewed the current advances on the helicase activity of RHA and its relevance to gene expression, particularly, to the genesis of circular RNA.
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Affiliation(s)
- Yuan-Qing Pan
- Institute of Biomedical Sciences, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi province, China
| | - Li Xing
- Institute of Biomedical Sciences, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi province, China
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45
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Maia N, Soares G, Silva C, Marques I, Rodrigues B, Santos R, Melo-Pires M, de Brouwer APM, Temudo T, Jorge P. Two Compound Heterozygous Variants in SNX14 Cause Stereotypies and Dystonia in Autosomal Recessive Spinocerebellar Ataxia 20. Front Genet 2020; 11:1038. [PMID: 33193593 PMCID: PMC7543990 DOI: 10.3389/fgene.2020.01038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/11/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nuno Maia
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Gabriela Soares
- Unidade de Genética Médica, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
| | - Cecília Silva
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Isabel Marques
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Bárbara Rodrigues
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Rosário Santos
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Manuel Melo-Pires
- Serviço de Neuropatologia, Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
| | - Arjan PM de Brouwer
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands
| | - Teresa Temudo
- Serviço de Neurologia Pediátrica, Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
| | - Paula Jorge
- Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães (CGM), Centro Hospitalar Universitário do Porto (CHUP), Porto, Portugal
- Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
- *Correspondence: Paula Jorge,
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Rahnama M, Novikova O, Starnes JH, Zhang S, Chen L, Farman ML. Transposon-mediated telomere destabilization: a driver of genome evolution in the blast fungus. Nucleic Acids Res 2020; 48:7197-7217. [PMID: 32558886 PMCID: PMC7367193 DOI: 10.1093/nar/gkaa287] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/03/2020] [Accepted: 04/14/2020] [Indexed: 01/01/2023] Open
Abstract
The fungus Magnaporthe oryzae causes devastating diseases of crops, including rice and wheat, and in various grasses. Strains from ryegrasses have highly unstable chromosome ends that undergo frequent rearrangements, and this has been associated with the presence of retrotransposons (Magnaporthe oryzae Telomeric Retrotransposons-MoTeRs) inserted in the telomeres. The objective of the present study was to determine the mechanisms by which MoTeRs promote telomere instability. Targeted cloning, mapping, and sequencing of parental and novel telomeric restriction fragments (TRFs), along with MinION sequencing of genomic DNA allowed us to document the precise molecular alterations underlying 109 newly-formed TRFs. These included truncations of subterminal rDNA sequences; acquisition of MoTeR insertions by 'plain' telomeres; insertion of the MAGGY retrotransposons into MoTeR arrays; MoTeR-independent expansion and contraction of subtelomeric tandem repeats; and a variety of rearrangements initiated through breaks in interstitial telomere tracts that are generated during MoTeR integration. Overall, we estimate that alterations occurred in approximately sixty percent of chromosomes (one in three telomeres) analyzed. Most importantly, we describe an entirely new mechanism by which transposons can promote genomic alterations at exceptionally high frequencies, and in a manner that can promote genome evolution while minimizing collateral damage to overall chromosome architecture and function.
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Affiliation(s)
- Mostafa Rahnama
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
| | - Olga Novikova
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
| | - John H Starnes
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
| | - Shouan Zhang
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
| | - Li Chen
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
| | - Mark L Farman
- Department of Plant Pathology, University of Kentucky, 1405 Veteran's Dr., Lexington, KY 40546, USA
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47
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Bruijnesteijn J, de Groot NG, Bontrop RE. The Genetic Mechanisms Driving Diversification of the KIR Gene Cluster in Primates. Front Immunol 2020; 11:582804. [PMID: 33013938 PMCID: PMC7516082 DOI: 10.3389/fimmu.2020.582804] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 08/18/2020] [Indexed: 12/26/2022] Open
Abstract
The activity and function of natural killer (NK) cells are modulated through the interactions of multiple receptor families, of which some recognize MHC class I molecules. The high level of MHC class I polymorphism requires their ligands either to interact with conserved epitopes, as is utilized by the NKG2A receptor family, or to co-evolve with the MHC class I allelic variation, which task is taken up by the killer cell immunoglobulin-like receptor (KIR) family. Multiple molecular mechanisms are responsible for the diversification of the KIR gene system, and include abundant chromosomal recombination, high mutation rates, alternative splicing, and variegated expression. The combination of these genetic mechanisms generates a compound array of diversity as is reflected by the contraction and expansion of KIR haplotypes, frequent birth of fusion genes, allelic polymorphism, structurally distinct isoforms, and variegated expression, which is in contrast to the mainly allelic nature of MHC class I polymorphism in humans. A comparison of the thoroughly studied human and macaque KIR gene repertoires demonstrates a similar evolutionarily conserved toolbox, through which selective forces drove and maintained the diversified nature of the KIR gene cluster. This hypothesis is further supported by the comparative genetics of KIR haplotypes and genes in other primate species. The complex nature of the KIR gene system has an impact upon the education, activity, and function of NK cells in coherence with an individual’s MHC class I repertoire and pathogenic encounters. Although selection operates on an individual, the continuous diversification of the KIR gene system in primates might protect populations against evolving pathogens.
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Affiliation(s)
- Jesse Bruijnesteijn
- Comparative Genetics and Refinement, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Natasja G de Groot
- Comparative Genetics and Refinement, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Ronald E Bontrop
- Comparative Genetics and Refinement, Biomedical Primate Research Centre, Rijswijk, Netherlands.,Theoretical Biology and Bioinformatics, Utrecht University, Utrecht, Netherlands
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48
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Suntsova MV, Buzdin AA. Differences between human and chimpanzee genomes and their implications in gene expression, protein functions and biochemical properties of the two species. BMC Genomics 2020; 21:535. [PMID: 32912141 PMCID: PMC7488140 DOI: 10.1186/s12864-020-06962-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 07/29/2020] [Indexed: 12/24/2022] Open
Abstract
Chimpanzees are the closest living relatives of humans. The divergence between human and chimpanzee ancestors dates to approximately 6,5-7,5 million years ago. Genetic features distinguishing us from chimpanzees and making us humans are still of a great interest. After divergence of their ancestor lineages, human and chimpanzee genomes underwent multiple changes including single nucleotide substitutions, deletions and duplications of DNA fragments of different size, insertion of transposable elements and chromosomal rearrangements. Human-specific single nucleotide alterations constituted 1.23% of human DNA, whereas more extended deletions and insertions cover ~ 3% of our genome. Moreover, much higher proportion is made by differential chromosomal inversions and translocations comprising several megabase-long regions or even whole chromosomes. However, despite of extensive knowledge of structural genomic changes accompanying human evolution we still cannot identify with certainty the causative genes of human identity. Most structural gene-influential changes happened at the level of expression regulation, which in turn provoked larger alterations of interactome gene regulation networks. In this review, we summarized the available information about genetic differences between humans and chimpanzees and their potential functional impacts on differential molecular, anatomical, physiological and cognitive peculiarities of these species.
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Affiliation(s)
- Maria V Suntsova
- Institute for personalized medicine, I.M. Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia
| | - Anton A Buzdin
- Institute for personalized medicine, I.M. Sechenov First Moscow State Medical University, Trubetskaya 8, Moscow, Russia. .,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Miklukho-Maklaya, 16/10, Moscow, Russia. .,Omicsway Corp, Walnut, CA, USA. .,Moscow Institute of Physics and Technology (National Research University), 141700, Moscow, Russia.
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49
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Complex Characterization of Germline Large Genomic Rearrangements of the BRCA1 and BRCA2 Genes in High-Risk Breast Cancer Patients-Novel Variants from a Large National Center. Int J Mol Sci 2020; 21:ijms21134650. [PMID: 32629901 PMCID: PMC7370166 DOI: 10.3390/ijms21134650] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/19/2020] [Accepted: 06/27/2020] [Indexed: 12/23/2022] Open
Abstract
Large genomic rearrangements (LGRs) affecting one or more exons of BRCA1 and BRCA2 constitute a significant part of the mutation spectrum of these genes. Since 2004, the National Institute of Oncology, Hungary, has been involved in screening for LGRs of breast or ovarian cancer families enrolled for genetic testing. LGRs were detected by multiplex ligation probe amplification method, or next-generation sequencing. Where it was possible, transcript-level characterization of LGRs was performed. Phenotype data were collected and analyzed too. Altogether 28 different types of LGRs in 51 probands were detected. Sixteen LGRs were novel. Forty-nine cases were deletions or duplications in BRCA1 and two affected BRCA2. Rearrangements accounted for 10% of the BRCA1 mutations. Three exon copy gains, two complex rearrangements, and 23 exon losses were characterized by exact breakpoint determinations. The inferred mechanisms for LGR formation were mainly end-joining repairs utilizing short direct homologies. Comparing phenotype features of the LGR-carriers to that of the non-LGR BRCA1 mutation carriers, revealed no significant differences. Our study is the largest comprehensive report of LGRs of BRCA1/2 in familial breast and ovarian cancer patients in the Middle and Eastern European region. Our data add novel insights to genetic interpretation associated to the LGRs.
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50
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Yoshiji S, Iwasaki Y, Iwasaki K, Honjo S, Hirano K, Ono K, Yamazaki Y, Sasano H, Hamasaki A. Alu-Mediated MEN1 Gene Deletion and Loss of Heterozygosity in a Patient with Multiple Endocrine Neoplasia Type 1. J Endocr Soc 2020; 4:bvaa051. [PMID: 32715270 PMCID: PMC7371388 DOI: 10.1210/jendso/bvaa051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Indexed: 01/15/2023] Open
Abstract
Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder caused by mutations of the tumor suppressor gene MEN1. Most of the germline MEN1 gene mutations have been small mutations, and the whole gene deletion is rarely observed. In the present study, we revealed Alu retrotransposon-mediated de novo germline deletion of the whole MEN1 gene and somatic copy-neutral loss of heterozygosity (LOH) in a patient with MEN1. The patient is a 39-year-old woman who was referred to our department for the management of prolactinoma. She was also diagnosed with primary hyperparathyroidism and suspected of MEN1. Although nucleotide sequencing did not detect any MEN1 gene mutations, multiplex ligation-dependent probe amplification (MLPA) revealed a large germline deletion of the MEN1 gene. Subsequent quantitative polymerase chain reaction (qPCR)–based copy number mapping showed a monoallelic loss of approximately 18.5-kilobase region containing the whole MEN1 gene. Intriguingly, the 2 breakpoints were flanked by Alu repetitive elements, suggesting the contribution of Alu/Alu-mediated rearrangements (AAMR) to the whole MEN1 gene deletion. Furthermore, copy number mapping using MLPA and qPCR in combination with single nucleotide polymorphism analysis revealed copy-neutral LOH as a somatic event for parathyroid tumorigenesis. In conclusion, copy number mapping revealed a novel combination of Alu/Alu-mediated de novo germline deletion of the MEN1 gene and somatic copy-neutral LOH as a cytogenetic basis for the MEN1 pathogenesis. Moreover, subsequent in silico analysis highlighted the possible predisposition of the MEN1 gene to Alu retrotransposon-mediated genomic deletion.
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Affiliation(s)
- Satoshi Yoshiji
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Yorihiro Iwasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Kanako Iwasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Sachiko Honjo
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Koichi Hirano
- Department of Laboratory Medicine, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Katsuhiko Ono
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Yuto Yamazaki
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Hironobu Sasano
- Department of Anatomic Pathology, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Akihiro Hamasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
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