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Dippenaar A, Ismail N, Heupink TH, Grobbelaar M, Loubser J, Van Rie A, Warren RM. Droplet based whole genome amplification for sequencing minute amounts of purified Mycobacterium tuberculosis DNA. Sci Rep 2024; 14:9931. [PMID: 38689002 PMCID: PMC11061190 DOI: 10.1038/s41598-024-60545-1] [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: 11/23/2023] [Accepted: 04/24/2024] [Indexed: 05/02/2024] Open
Abstract
Implementation of whole genome sequencing (WGS) for patient care is hindered by limited Mycobacterium tuberculosis (Mtb) in clinical specimens and slow Mtb growth. We evaluated droplet multiple displacement amplification (dMDA) for amplification of minute amounts of Mtb DNA to enable WGS as an alternative to other Mtb enrichment methods. Purified genomic Mtb-DNA (0.1, 0.5, 1, and 5 pg) was encapsulated and amplified using the Samplix Xdrop-instrument and sequenced alongside a control sample using standard Illumina protocols followed by MAGMA-analysis. The control and 5 pg input dMDA samples underwent nanopore sequencing followed by Nanoseq and TB-profiler analysis. dMDA generated 105-2400 ng DNA from the 0.1-5 pg input DNA, respectively. Followed by Illumina WGS, dMDA raised mean sequencing depth from 7 × for 0.1 pg input DNA to ≥ 60 × for 5 pg input and the control sample. Bioinformatic analysis revealed a high number of false positive and false negative variants when amplifying ≤ 0.5 pg input DNA. Nanopore sequencing of the 5 pg dMDA sample presented excellent coverage depth, breadth, and accurate strain characterization, albeit elevated false positive and false negative variants compared to Illumina-sequenced dMDA sample with identical Mtb DNA input. dMDA coupled with Illumina WGS for samples with ≥ 5 pg purified Mtb DNA, equating to approximately 1000 copies of the Mtb genome, offers precision for drug resistance, phylogeny, and transmission insights.
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Affiliation(s)
- Anzaan Dippenaar
- Tuberculosis Omics Research Consortium, Department of Family Medicine and Population Health, Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.
| | - Nabila Ismail
- South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Tim H Heupink
- Tuberculosis Omics Research Consortium, Department of Family Medicine and Population Health, Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Melanie Grobbelaar
- South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Johannes Loubser
- South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Annelies Van Rie
- Tuberculosis Omics Research Consortium, Department of Family Medicine and Population Health, Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Robin M Warren
- South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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2
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Zarka KA, Jagd LM, Douches DS. T-DNA characterization of genetically modified 3-R-gene late blight-resistant potato events with a novel procedure utilizing the Samplix Xdrop ® enrichment technology. FRONTIERS IN PLANT SCIENCE 2024; 15:1330429. [PMID: 38419775 PMCID: PMC10900525 DOI: 10.3389/fpls.2024.1330429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/22/2024] [Indexed: 03/02/2024]
Abstract
Before the commercialization of genetically modified crops, the events carrying the novel DNA must be thoroughly evaluated for agronomic, nutritional, and molecular characteristics. Over the years, polymerase chain reaction-based methods, Southern blot, and short-read sequencing techniques have been utilized for collecting molecular characterization data. Multiple genomic applications are necessary to determine the insert location, flanking sequence analysis, characterization of the inserted DNA, and determination of any interruption of native genes. These techniques are time-consuming and labor-intensive, making it difficult to characterize multiple events. Current advances in sequencing technologies are enabling whole-genomic sequencing of modified crops to obtain full molecular characterization. However, in polyploids, such as the tetraploid potato, it is a challenge to obtain whole-genomic sequencing coverage that meets the regulatory approval of the genetic modification. Here we describe an alternative to labor-intensive applications with a novel procedure using Samplix Xdrop® enrichment technology and next-generation Nanopore sequencing technology to more efficiently characterize the T-DNA insertions of four genetically modified potato events developed by the Feed the Future Global Biotech Potato Partnership: DIA_MSU_UB015, DIA_MSU_UB255, GRA_MSU_UG234, and GRA_MSU_UG265 (derived from regionally important varieties Diamant and Granola). Using the Xdrop® /Nanopore technique, we obtained a very high sequence read coverage within the T-DNA and junction regions. In three of the four events, we were able to use the data to confirm single T-DNA insertions, identify insert locations, identify flanking sequences, and characterize the inserted T-DNA. We further used the characterization data to identify native gene interruption and confirm the stability of the T-DNA across clonal cycles. These results demonstrate the functionality of using the Xdrop® /Nanopore technique for T-DNA characterization. This research will contribute to meeting regulatory safety and regulatory approval requirements for commercialization with small shareholder farmers in target countries within our partnership.
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Affiliation(s)
- Kelly A. Zarka
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | | | - David S. Douches
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
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3
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Ying J, Mao L, Tang Y, Fassatoui M, Song W, Xu X, Tang X, Li J, Liu H, Jian F, Du Q, Wong G, Feng W, Berthet N. Development and validation of real-time recombinase polymerase amplification-based assays for detecting HPV16 and HPV18 DNA. Microbiol Spectr 2023; 11:e0120723. [PMID: 37787547 PMCID: PMC10714791 DOI: 10.1128/spectrum.01207-23] [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: 03/30/2023] [Accepted: 08/08/2023] [Indexed: 10/04/2023] Open
Abstract
IMPORTANCE HPV DNA screening is an effective approach for the prevention of cervical cancer. The novel real-time recombinase polymerase amplification-based HPV detection systems we developed constitute an improvement over the HPV detection methods currently used in clinical practice and should help to extend cervical cancer screening in the future, particularly in point-of-care test settings.
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Affiliation(s)
- Jiaxu Ying
- Centre for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Unit of Discovery and Molecular Characterization of Pathogens, Shanghai, China
- Viral Hemorrhagic Fevers Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Lingjing Mao
- Centre for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Unit of Discovery and Molecular Characterization of Pathogens, Shanghai, China
- Viral Hemorrhagic Fevers Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Yujing Tang
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meriem Fassatoui
- Centre for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Unit of Discovery and Molecular Characterization of Pathogens, Shanghai, China
| | - Wei Song
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaosheng Xu
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaojian Tang
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Li
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hua Liu
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fangfang Jian
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qinwen Du
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Gary Wong
- Viral Hemorrhagic Fevers Research Unit, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Weiwei Feng
- Department of Obstetrics and Gynecology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nicolas Berthet
- Centre for Microbes, Development and Health, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Unit of Discovery and Molecular Characterization of Pathogens, Shanghai, China
- Institut Pasteur, Université Paris-Cite, Unité Environnement et Risque Infectieux, Cellule d’Intervention Biologique d’Urgence, Paris, France
- Institut Pasteur, Université Paris-cite, Unité Epidémiologie et Physiopathologie des Virus Oncogènes, Paris, France
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4
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Kirov I. Toward Transgene-Free Transposon-Mediated Biological Mutagenesis for Plant Breeding. Int J Mol Sci 2023; 24:17054. [PMID: 38069377 PMCID: PMC10706983 DOI: 10.3390/ijms242317054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Genetic diversity is a key factor for plant breeding. The birth of novel genic and genomic variants is also crucial for plant adaptation in nature. Therefore, the genomes of almost all living organisms possess natural mutagenic mechanisms. Transposable elements (TEs) are a major mutagenic force driving genetic diversity in wild plants and modern crops. The relatively rare TE transposition activity during the thousand-year crop domestication process has led to the phenotypic diversity of many cultivated species. The utilization of TE mutagenesis by artificial and transient acceleration of their activity in a controlled mode is an attractive foundation for a novel type of mutagenesis called TE-mediated biological mutagenesis. Here, I focus on TEs as mutagenic sources for plant breeding and discuss existing and emerging transgene-free approaches for TE activation in plants. Furthermore, I also review the non-randomness of TE insertions in a plant genome and the molecular and epigenetic factors involved in shaping TE insertion preferences. Additionally, I discuss the molecular mechanisms that prevent TE transpositions in germline plant cells (e.g., meiocytes, pollen, egg and embryo cells, and shoot apical meristem), thereby reducing the chances of TE insertion inheritance. Knowledge of these mechanisms can expand the TE activation toolbox using novel gene targeting approaches. Finally, the challenges and future perspectives of plant populations with induced novel TE insertions (iTE plant collections) are discussed.
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Affiliation(s)
- Ilya Kirov
- All-Russia Research Institute of Agricultural Biotechnology, 127550 Moscow, Russia;
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
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5
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Giovenino C, Trajkova S, Pavinato L, Cardaropoli S, Pullano V, Ferrero E, Sukarova-Angelovska E, Carestiato S, Salmin P, Rinninella A, Battaglia A, Bertoli L, Fadda A, Palermo F, Carli D, Mussa A, Dimartino P, Bruselles A, Froukh T, Mandrile G, Pasini B, De Rubeis S, Buxbaum JD, Pippucci T, Tartaglia M, Rossato M, Delledonne M, Ferrero GB, Brusco A. Skewed X-chromosome inactivation in unsolved neurodevelopmental disease cases can guide re-evaluation For X-linked genes. Eur J Hum Genet 2023; 31:1228-1236. [PMID: 36879111 PMCID: PMC10620389 DOI: 10.1038/s41431-023-01324-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/24/2023] [Accepted: 02/20/2023] [Indexed: 03/08/2023] Open
Abstract
Despite major advances in genome technology and analysis, >50% of patients with a neurodevelopmental disorder (NDD) remain undiagnosed after extensive evaluation. A point in case is our clinically heterogeneous cohort of NDD patients that remained undiagnosed after FRAXA testing, chromosomal microarray analysis and trio exome sequencing (ES). In this study, we explored the frequency of non-random X chromosome inactivation (XCI) in the mothers of male patients and affected females, the rationale being that skewed XCI might be masking previously discarded genetic variants found on the X chromosome. A multiplex fluorescent PCR-based assay was used to analyse the pattern of XCI after digestion with HhaI methylation-sensitive restriction enzyme. In families with skewed XCI, we re-evaluated trio-based ES and identified pathogenic variants and a deletion on the X chromosome. Linkage analysis and RT-PCR were used to further study the inactive X chromosome allele, and Xdrop long-DNA technology was used to define chromosome deletion boundaries. We found skewed XCI (>90%) in 16/186 (8.6%) mothers of NDD males and in 12/90 (13.3%) NDD females, far beyond the expected rate of XCI in the normal population (3.6%, OR = 4.10; OR = 2.51). By re-analyzing ES and clinical data, we solved 7/28 cases (25%) with skewed XCI, identifying variants in KDM5C, PDZD4, PHF6, TAF1, OTUD5 and ZMYM3, and a deletion in ATRX. We conclude that XCI profiling is a simple assay that targets a subgroup of patients that can benefit from re-evaluation of X-linked variants, thus improving the diagnostic yield in NDD patients and identifying new X-linked disorders.
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Affiliation(s)
- Chiara Giovenino
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Slavica Trajkova
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Lisa Pavinato
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Simona Cardaropoli
- Department of Public Health and Pediatrics, University of Turin, 10126, Turin, Italy
| | - Verdiana Pullano
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Enza Ferrero
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Elena Sukarova-Angelovska
- Department of Endocrinology and Genetics, University Clinic for Pediatric Diseases, Faculty of Medicine, Ss. Cyril and Methodius University in Skopje, 1000, Skopje, Republic of North Macedonia
| | - Silvia Carestiato
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Paola Salmin
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, 10126, Turin, Italy
| | - Antonina Rinninella
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
- Department of Biomedical and Biotechnological Sciences, Medical Genetics, University of Catania, 94124, Catania, Italy
| | - Anthony Battaglia
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Luca Bertoli
- Functional Genomics Lab, Department of Biotechnology, University of Verona, 37134, Verona, Italy
| | - Antonio Fadda
- Functional Genomics Lab, Department of Biotechnology, University of Verona, 37134, Verona, Italy
| | - Flavia Palermo
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
| | - Diana Carli
- Department of Public Health and Pediatrics, University of Turin, 10126, Turin, Italy
| | - Alessandro Mussa
- Department of Public Health and Pediatrics, University of Turin, 10126, Turin, Italy
| | - Paola Dimartino
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Alessandro Bruselles
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Tawfiq Froukh
- Department of Biotechnology and Genetic Engineering, Philadelphia University, Amman, Jordan
| | - Giorgia Mandrile
- Medical Genetics Unit and Thalassemia Center, San Luigi University Hospital, University of Torino, Orbassano, TO, Italy
| | - Barbara Pasini
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, 10126, Turin, Italy
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Joseph D Buxbaum
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Tommaso Pippucci
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italia
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146, Rome, Italy
| | - Marzia Rossato
- Functional Genomics Lab, Department of Biotechnology, University of Verona, 37134, Verona, Italy
| | - Massimo Delledonne
- Functional Genomics Lab, Department of Biotechnology, University of Verona, 37134, Verona, Italy
| | | | - Alfredo Brusco
- Department of Medical Sciences, University of Turin, 10126, Turin, Italy.
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, 10126, Turin, Italy.
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6
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Merkulov P, Gvaramiya S, Dudnikov M, Komakhin R, Omarov M, Kocheshkova A, Konstantinov Z, Soloviev A, Karlov G, Divashuk M, Kirov I. Cas9-targeted Nanopore sequencing rapidly elucidates the transposition preferences and DNA methylation profiles of mobile elements in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2242-2261. [PMID: 37555565 DOI: 10.1111/jipb.13555] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/27/2023] [Accepted: 08/08/2023] [Indexed: 08/10/2023]
Abstract
Transposable element insertions (TEIs) are an important source of genomic innovation by contributing to plant adaptation, speciation, and the production of new varieties. The often large, complex plant genomes make identifying TEIs from short reads difficult and expensive. Moreover, rare somatic insertions that reflect mobilome dynamics are difficult to track using short reads. To address these challenges, we combined Cas9-targeted Nanopore sequencing (CANS) with the novel pipeline NanoCasTE to trace both genetically inherited and somatic TEIs in plants. We performed CANS of the EVADÉ (EVD) retrotransposon in wild-type Arabidopsis thaliana and rapidly obtained up to 40× sequence coverage. Analysis of hemizygous T-DNA insertion sites and genetically inherited insertions of the EVD transposon in the ddm1 (decrease in DNA methylation 1) genome uncovered the crucial role of DNA methylation in shaping EVD insertion preference. We also investigated somatic transposition events of the ONSEN transposon family, finding that genes that are downregulated during heat stress are preferentially targeted by ONSENs. Finally, we detected hypomethylation of novel somatic insertions for two ONSENs. CANS and NanoCasTE are effective tools for detecting TEIs and exploring mobilome organization in plants in response to stress and in different genetic backgrounds, as well as screening T-DNA insertion mutants and transgenic plants.
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Affiliation(s)
- Pavel Merkulov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, 141701, Russia
| | - Sofya Gvaramiya
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Maxim Dudnikov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, 141701, Russia
| | - Roman Komakhin
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Murad Omarov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Alina Kocheshkova
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Zakhar Konstantinov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Alexander Soloviev
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
- All-Russia Center for Plant Quarantine, Ramenski, 140150, Russia
- N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences, Moscow, 127276, Russia
| | - Gennady Karlov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Mikhail Divashuk
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
| | - Ilya Kirov
- All-Russia Research Institute of Agricultural Biotechnology, Moscow, 127550, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, 141701, Russia
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7
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Hook PW, Timp W. Beyond assembly: the increasing flexibility of single-molecule sequencing technology. Nat Rev Genet 2023; 24:627-641. [PMID: 37161088 PMCID: PMC10169143 DOI: 10.1038/s41576-023-00600-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 05/11/2023]
Abstract
The maturation of high-throughput short-read sequencing technology over the past two decades has shaped the way genomes are studied. Recently, single-molecule, long-read sequencing has emerged as an essential tool in deciphering genome structure and function, including filling gaps in the human reference genome, measuring the epigenome and characterizing splicing variants in the transcriptome. With recent technological developments, these single-molecule technologies have moved beyond genome assembly and are being used in a variety of ways, including to selectively sequence specific loci with long reads, measure chromatin state and protein-DNA binding in order to investigate the dynamics of gene regulation, and rapidly determine copy number variation. These increasingly flexible uses of single-molecule technologies highlight a young and fast-moving part of the field that is leading to a more accessible era of nucleic acid sequencing.
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Affiliation(s)
- Paul W Hook
- Department of Biomedical Engineering, Molecular Biology and Genetics, and Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Winston Timp
- Department of Biomedical Engineering, Molecular Biology and Genetics, and Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA.
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8
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Hård J, Mold JE, Eisfeldt J, Tellgren-Roth C, Häggqvist S, Bunikis I, Contreras-Lopez O, Chin CS, Nordlund J, Rubin CJ, Feuk L, Michaëlsson J, Ameur A. Long-read whole-genome analysis of human single cells. Nat Commun 2023; 14:5164. [PMID: 37620373 PMCID: PMC10449900 DOI: 10.1038/s41467-023-40898-3] [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: 02/06/2023] [Accepted: 08/07/2023] [Indexed: 08/26/2023] Open
Abstract
Long-read sequencing has dramatically increased our understanding of human genome variation. Here, we demonstrate that long-read technology can give new insights into the genomic architecture of individual cells. Clonally expanded CD8+ T-cells from a human donor were subjected to droplet-based multiple displacement amplification (dMDA) to generate long molecules with reduced bias. PacBio sequencing generated up to 40% genome coverage per single-cell, enabling detection of single nucleotide variants (SNVs), structural variants (SVs), and tandem repeats, also in regions inaccessible by short reads. 28 somatic SNVs were detected, including one case of mitochondrial heteroplasmy. 5473 high-confidence SVs/cell were discovered, a sixteen-fold increase compared to Illumina-based results from clonally related cells. Single-cell de novo assembly generated a genome size of up to 598 Mb and 1762 (12.8%) complete gene models. In summary, our work shows the promise of long-read sequencing toward characterization of the full spectrum of genetic variation in single cells.
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Affiliation(s)
- Joanna Hård
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland.
- ETH AI Center, ETH Zurich, Zurich, Switzerland.
| | - Jeff E Mold
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jesper Eisfeldt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Christian Tellgren-Roth
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Susana Häggqvist
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Ignas Bunikis
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | | | | | - Jessica Nordlund
- Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Carl-Johan Rubin
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Lars Feuk
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Jakob Michaëlsson
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Adam Ameur
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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9
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Tschernoster N, Erger F, Kohl S, Reusch B, Wenzel A, Walsh S, Thiele H, Becker C, Franitza M, Bartram MP, Kömhoff M, Schumacher L, Kukat C, Borodina T, Quedenau C, Nürnberg P, Rinschen MM, Driller JH, Pedersen BP, Schlingmann KP, Hüttel B, Bockenhauer D, Beck B, Altmüller J. Long-read sequencing identifies a common transposition haplotype predisposing for CLCNKB deletions. Genome Med 2023; 15:62. [PMID: 37612755 PMCID: PMC10464140 DOI: 10.1186/s13073-023-01215-1] [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: 03/15/2023] [Accepted: 07/27/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND Long-read sequencing is increasingly used to uncover structural variants in the human genome, both functionally neutral and deleterious. Structural variants occur more frequently in regions with a high homology or repetitive segments, and one rearrangement may predispose to additional events. Bartter syndrome type 3 (BS 3) is a monogenic tubulopathy caused by deleterious variants in the chloride channel gene CLCNKB, a high proportion of these being large gene deletions. Multiplex ligation-dependent probe amplification, the current diagnostic gold standard for this type of mutation, will indicate a simple homozygous gene deletion in biallelic deletion carriers. However, since the phenotypic spectrum of BS 3 is broad even among biallelic deletion carriers, we undertook a more detailed analysis of precise breakpoint regions and genomic structure. METHODS Structural variants in 32 BS 3 patients from 29 families and one BS4b patient with CLCNKB deletions were investigated using long-read and synthetic long-read sequencing, as well as targeted long-read sequencing approaches. RESULTS We report a ~3 kb duplication of 3'-UTR CLCNKB material transposed to the corresponding locus of the neighbouring CLCNKA gene, also found on ~50 % of alleles in healthy control individuals. This previously unknown common haplotype is significantly enriched in our cohort of patients with CLCNKB deletions (45 of 51 alleles with haplotype information, 2.2 kb and 3.0 kb transposition taken together, p=9.16×10-9). Breakpoint coordinates for the CLCNKB deletion were identifiable in 28 patients, with three being compound heterozygous. In total, eight different alleles were found, one of them a complex rearrangement with three breakpoint regions. Two patients had different CLCNKA/CLCNKB hybrid genes encoding a predicted CLCNKA/CLCNKB hybrid protein with likely residual function. CONCLUSIONS The presence of multiple different deletion alleles in our cohort suggests that large CLCNKB gene deletions originated from many independently recurring genomic events clustered in a few hot spots. The uncovered associated sequence transposition haplotype apparently predisposes to these additional events. The spectrum of CLCNKB deletion alleles is broader than expected and likely still incomplete, but represents an obvious candidate for future genotype/phenotype association studies. We suggest a sensitive and cost-efficient approach, consisting of indirect sequence capture and long-read sequencing, to analyse disease-relevant structural variant hotspots in general.
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Affiliation(s)
- Nikolai Tschernoster
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Florian Erger
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stefan Kohl
- Department of Pediatrics, Cologne Children's Hospital, Cologne, Germany
| | - Björn Reusch
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Andrea Wenzel
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stephen Walsh
- Department of Renal Medicine, UCL, University College London, London, UK
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Christian Becker
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Marek Franitza
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Malte P Bartram
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Cologne, Germany
| | - Martin Kömhoff
- Department of Pediatrics, University Marburg, Marburg, Germany
| | - Lena Schumacher
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Christian Kukat
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Tatiana Borodina
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Claudia Quedenau
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
- Department III of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan H Driller
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Bjørn P Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Bruno Hüttel
- Max Planck Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Detlef Bockenhauer
- Department of Renal Medicine, UCL, University College London, London, UK
- Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Bodo Beck
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Janine Altmüller
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany.
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Core Facility Genomics, Berlin, Germany.
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10
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Hunt JMT, Samson CA, Rand AD, Sheppard HM. Unintended CRISPR-Cas9 editing outcomes: a review of the detection and prevalence of structural variants generated by gene-editing in human cells. Hum Genet 2023; 142:705-720. [PMID: 37093294 PMCID: PMC10182114 DOI: 10.1007/s00439-023-02561-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/13/2023] [Indexed: 04/25/2023]
Abstract
Genome editing using the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas) gene-editing system (CRISPR-Cas) is a valuable tool for fundamental and applied research applications. Significant improvements in editing efficacy have advanced genome editing strategies into phase 3 human clinical trials. However, recent studies suggest that our understanding of editing outcomes has lagged behind the developments made in generating the edits themselves. While many researchers have analyzed on- and off-target events through the lens of small insertions or deletions at predicted sites, screens for larger structural variants (SVs) and chromosomal abnormalities are not routinely performed. Full and comprehensive validation of on- and off-target effects is required to ensure reproducibility and to accurately assess the safety of future editing applications. Here we review SVs associated with CRISPR-editing in cells of human origin and highlight the methods used to detect and avoid them.
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Affiliation(s)
| | | | - Alex du Rand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Hilary M Sheppard
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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11
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Skowronek D, Pilz RA, Bonde L, Schamuhn OJ, Feldmann JL, Hoffjan S, Much CD, Felbor U, Rath M. Cas9-Mediated Nanopore Sequencing Enables Precise Characterization of Structural Variants in CCM Genes. Int J Mol Sci 2022; 23:ijms232415639. [PMID: 36555281 PMCID: PMC9779250 DOI: 10.3390/ijms232415639] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/05/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Deletions in the CCM1, CCM2, and CCM3 genes are a common cause of familial cerebral cavernous malformations (CCMs). In current molecular genetic laboratories, targeted next-generation sequencing or multiplex ligation-dependent probe amplification are mostly used to identify copy number variants (CNVs). However, both techniques are limited in their ability to specify the breakpoints of CNVs and identify complex structural variants (SVs). To overcome these constraints, we established a targeted Cas9-mediated nanopore sequencing approach for CNV detection with single nucleotide resolution. Using a MinION device, we achieved complete coverage for the CCM genes and determined the exact size of CNVs in positive controls. Long-read sequencing for a CCM1 and CCM2 CNV revealed that the adjacent ANKIB1 and NACAD genes were also partially or completely deleted. In addition, an interchromosomal insertion and an inversion in CCM2 were reliably re-identified by long-read sequencing. The refinement of CNV breakpoints by long-read sequencing enabled fast and inexpensive PCR-based variant confirmation, which is highly desirable to reduce costs in subsequent family analyses. In conclusion, Cas9-mediated nanopore sequencing is a cost-effective and flexible tool for molecular genetic diagnostics which can be easily adapted to various target regions.
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Affiliation(s)
- Dariush Skowronek
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Robin A. Pilz
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Loisa Bonde
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Ole J. Schamuhn
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Janne L. Feldmann
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Sabine Hoffjan
- Department of Human Genetics, Ruhr-University, 44801 Bochum, Germany
| | - Christiane D. Much
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Ute Felbor
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
| | - Matthias Rath
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, 17475 Greifswald, Germany
- Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, 20457 Hamburg, Germany
- Correspondence:
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12
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Chen H, Durinck S, Patel H, Foreman O, Mesh K, Eastham J, Caothien R, Newman RJ, Roose-Girma M, Darmanis S, Warming S, Lattanzi A, Liang Y, Haley B. Population-wide gene disruption in the murine lung epithelium via AAV-mediated delivery of CRISPR-Cas9 components. MOLECULAR THERAPY - METHODS & CLINICAL DEVELOPMENT 2022; 27:431-449. [DOI: 10.1016/j.omtm.2022.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022]
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13
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Geng K, Merino LG, Wedemann L, Martens A, Sobota M, Sanchez YP, Søndergaard JN, White RJ, Kutter C. Target-enriched nanopore sequencing and de novo assembly reveals co-occurrences of complex on-target genomic rearrangements induced by CRISPR-Cas9 in human cells. Genome Res 2022; 32:1876-1891. [PMID: 36180232 PMCID: PMC9712622 DOI: 10.1101/gr.276901.122] [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: 05/05/2022] [Accepted: 09/19/2022] [Indexed: 11/24/2022]
Abstract
The CRISPR-Cas9 system is widely used to permanently delete genomic regions via dual guide RNAs. Genomic rearrangements induced by CRISPR-Cas9 can occur, but continuous technical developments make it possible to characterize complex on-target effects. We combined an innovative droplet-based target enrichment approach with long-read sequencing and coupled it to a customized de novo sequence assembly. This approach enabled us to dissect the sequence content at kilobase scale within an on-target genomic locus. We here describe extensive genomic disruptions by Cas9, involving the allelic co-occurrence of a genomic duplication and inversion of the target region, as well as integrations of exogenous DNA and clustered interchromosomal DNA fragment rearrangements. Furthermore, we found that these genomic alterations led to functional aberrant DNA fragments and can alter cell proliferation. Our findings broaden the consequential spectrum of the Cas9 deletion system, reinforce the necessity of meticulous genomic validations, and introduce a data-driven workflow enabling detailed dissection of the on-target sequence content with superior resolution.
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Affiliation(s)
- Keyi Geng
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Lara G Merino
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Linda Wedemann
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Aniek Martens
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Małgorzata Sobota
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Yerma P Sanchez
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Jonas Nørskov Søndergaard
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Robert J White
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
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14
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Hua Z, Man J, Liu G, Li J, Zhou C, Xia H, Li J. Complex Suspended Janus Droplets Constructed through Solvent Evaporation-Induced Phase Separation at the Air-Liquid Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10994-11002. [PMID: 36048165 DOI: 10.1021/acs.langmuir.2c01460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phase separation technology has attracted extensive scientific interest because of its intriguing structure changes during the phase separation process. Phase separation inside emulsion droplets in continuous surroundings has been well studied in recent years. Many investigations have also been conducted to study the droplet phase separation phenomena in noncontinuous surroundings. However, studies on the phase separation phenomena and the spreading behavior of suspended droplets at the air-liquid interface were rarely reported. In this study, PEGDA-glycerol suspended Janus droplets with a patchy structure were produced by utilizing solvent evaporation-induced droplet phase separation at the air-liquid interface. By altering the glycerol/PEGDA volume ratio, the initial proportion of ethanol, and the concentration of surfactants, suspended droplets with different morphologies can be achieved, which include filbert-shaped droplets (FSDs), half lotus seedpod single-phase Janus droplets (HLSDs), lotus seedpod single-phase Janus droplets (LSDs), lotus seedpod-shaped droplets (LSSDs), multiple-bulge droplets (MBDs), and half gourd-shaped droplets (HGSDs). A patchy structure was generated at the air-droplet interface, which was attributed to the Marangoni stresses induced by nonuniform evaporation. Furthermore, a modified spreading coefficient theory was constructed and verified to illustrate the phase separation at the air-droplet interface, which was the first research to predict the phase separation phenomena at the air-liquid interface via spreading coefficients theory. Moreover, we studied the factors that led to the droplets being able to float by designing the combined parameters, including three interfacial tensions and the equilibrium contact angles. Therefore, a simple and versatile strategy for creating suspended Janus droplets has been developed for the first time, which holds significant potential in a variety of applications for material synthesis, such as the electrospinning solution behavior when sprayed from the nozzle into the air.
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Affiliation(s)
| | | | | | | | - Chenchen Zhou
- State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, P. R. China
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15
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Unraveling Structural Rearrangements of the CFH Gene Cluster in Atypical Hemolytic Uremic Syndrome Patients Using Molecular Combing and Long-Fragment Targeted Sequencing. J Mol Diagn 2022; 24:619-631. [PMID: 35398599 DOI: 10.1016/j.jmoldx.2022.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 02/01/2022] [Accepted: 02/25/2022] [Indexed: 11/22/2022] Open
Abstract
Complement factor H (CFH) and its related proteins have an essential role in regulating the alternative pathway of the complement system. Mutations and structural variants (SVs) of the CFH gene cluster, consisting of CFH and its five related genes (CFHR1-5), have been reported in renal pathologies as well as in complex immune diseases like age-related macular degeneration and systemic lupus erythematosus. SV analysis of this cluster is challenging because of its high degree of sequence homology. Following first-line next-generation sequencing gene panel sequencing, we applied Genomic Vision's Molecular Combing Technology to detect and visualize SVs within the CFH gene cluster and resolve its structural haplotypes completely. This approach was tested in three patients with atypical hemolytic uremic syndrome and known SVs and 18 patients with atypical hemolytic uremic syndrome or complement factor 3 glomerulopathy with unknown CFH gene cluster haplotypes. Three SVs, a CFH/CFHR1 hybrid gene in two patients and a rare heterozygous CFHR4/CFHR1 deletion in trans with the common CFHR3/CFHR1 deletion in a third patient, were newly identified. For the latter, the breakpoints were determined using a targeted enrichment approach for long DNA fragments (Samplix Xdrop) in combination with Oxford Nanopore sequencing. Molecular combing in addition to next-generation sequencing was able to improve the molecular genetic yield in this pilot study. This (cost-)effective approach warrants validation in larger cohorts with CFH/CFHR-associated disease.
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16
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Höijer I, Emmanouilidou A, Östlund R, van Schendel R, Bozorgpana S, Tijsterman M, Feuk L, Gyllensten U, den Hoed M, Ameur A. CRISPR-Cas9 induces large structural variants at on-target and off-target sites in vivo that segregate across generations. Nat Commun 2022; 13:627. [PMID: 35110541 PMCID: PMC8810904 DOI: 10.1038/s41467-022-28244-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/04/2022] [Indexed: 02/07/2023] Open
Abstract
CRISPR-Cas9 genome editing has potential to cure diseases without current treatments, but therapies must be safe. Here we show that CRISPR-Cas9 editing can introduce unintended mutations in vivo, which are passed on to the next generation. By editing fertilized zebrafish eggs using four guide RNAs selected for off-target activity in vitro, followed by long-read sequencing of DNA from >1100 larvae, juvenile and adult fish across two generations, we find that structural variants (SVs), i.e., insertions and deletions ≥50 bp, represent 6% of editing outcomes in founder larvae. These SVs occur both at on-target and off-target sites. Our results also illustrate that adult founder zebrafish are mosaic in their germ cells, and that 26% of their offspring carries an off-target mutation and 9% an SV. Hence, pre-testing for off-target activity and SVs using patient material is advisable in clinical applications, to reduce the risk of unanticipated effects with potentially large implications.
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Affiliation(s)
- Ida Höijer
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
| | - Anastasia Emmanouilidou
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
- The Beijer laboratory and Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Rebecka Östlund
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Selma Bozorgpana
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Lars Feuk
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Ulf Gyllensten
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Marcel den Hoed
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
- The Beijer laboratory and Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Adam Ameur
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.
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Kirov I, Polkhovskaya E, Dudnikov M, Merkulov P, Vlasova A, Karlov G, Soloviev A. Searching for a Needle in a Haystack: Cas9-Targeted Nanopore Sequencing and DNA Methylation Profiling of Full-Length Glutenin Genes in a Big Cereal Genome. PLANTS (BASEL, SWITZERLAND) 2021; 11:5. [PMID: 35009008 PMCID: PMC8746966 DOI: 10.3390/plants11010005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/16/2021] [Accepted: 12/16/2021] [Indexed: 12/29/2022]
Abstract
Sequencing and epigenetic profiling of target genes in plants are important tasks with various applications ranging from marker design for plant breeding to the study of gene expression regulation. This is particularly interesting for plants with big genome size for which whole-genome sequencing can be time-consuming and costly. In this study, we asked whether recently proposed Cas9-targeted nanopore sequencing (nCATS) is efficient for target gene sequencing for plant species with big genome size. We applied nCATS to sequence the full-length glutenin genes (Glu-1Ax, Glu-1Bx and Glu-1By) and their promoters in hexaploid triticale (X Triticosecale, AABBRR, genome size is 24 Gb). We showed that while the target gene enrichment per se was quite high for the three glutenin genes (up to 645×), the sequencing depth that was achieved from two MinION flowcells was relatively low (5-17×). However, this sequencing depth was sufficient for various tasks including detection of InDels and single-nucleotide variations (SNPs), read phasing and methylation profiling. Using nCATS, we uncovered SNP and InDel variation of full-length glutenin genes providing useful information for marker design and deciphering of variation of individual Glu-1By alleles. Moreover, we demonstrated that glutenin genes possess a 'gene-body' methylation epigenetic profile with hypermethylated CDS part and hypomethylated promoter region. The obtained information raised an interesting question on the role of gene-body methylation in glutenin gene expression regulation. Taken together, our work disclosures the potential of the nCATS approach for sequencing of target genes in plants with big genome size.
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Affiliation(s)
- Ilya Kirov
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
- Kurchatov Genomics Center of ARRIAB, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia
| | - Ekaterina Polkhovskaya
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
| | - Maxim Dudnikov
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
- Kurchatov Genomics Center of ARRIAB, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia
| | - Pavel Merkulov
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
| | - Anastasia Vlasova
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
| | - Gennady Karlov
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
| | - Alexander Soloviev
- Laboratory of Marker-Assisted and Genomic Selection of Plants, All-Russia Research Institute of Agricultural Biotechnology, Timiryazevskaya Str. 42, 127550 Moscow, Russia; (E.P.); (M.D.); (P.M.); (A.V.); (G.K.); (A.S.)
- N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences, Botanicheskaya Str. 4, 127276 Moscow, Russia
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18
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Grosso V, Marcolungo L, Maestri S, Alfano M, Lavezzari D, Iadarola B, Salviati A, Mariotti B, Botta A, D’Apice MR, Novelli G, Delledonne M, Rossato M. Characterization of FMR1 Repeat Expansion and Intragenic Variants by Indirect Sequence Capture. Front Genet 2021; 12:743230. [PMID: 34646309 PMCID: PMC8504923 DOI: 10.3389/fgene.2021.743230] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 08/26/2021] [Indexed: 11/30/2022] Open
Abstract
Traditional methods for the analysis of repeat expansions, which underlie genetic disorders, such as fragile X syndrome (FXS), lack single-nucleotide resolution in repeat analysis and the ability to characterize causative variants outside the repeat array. These drawbacks can be overcome by long-read and short-read sequencing, respectively. However, the routine application of next-generation sequencing in the clinic requires target enrichment, and none of the available methods allows parallel analysis of long-DNA fragments using both sequencing technologies. In this study, we investigated the use of indirect sequence capture (Xdrop technology) coupled to Nanopore and Illumina sequencing to characterize FMR1, the gene responsible of FXS. We achieved the efficient enrichment (> 200×) of large target DNA fragments (~60-80 kbp) encompassing the entire FMR1 gene. The analysis of Xdrop-enriched samples by Nanopore long-read sequencing allowed the complete characterization of repeat lengths in samples with normal, pre-mutation, and full mutation status (> 1 kbp), and correctly identified repeat interruptions relevant for disease prognosis and transmission. Single-nucleotide variants (SNVs) and small insertions/deletions (indels) could be detected in the same samples by Illumina short-read sequencing, completing the mutational testing through the identification of pathogenic variants within the FMR1 gene, when no typical CGG repeat expansion is detected. The study successfully demonstrated the parallel analysis of repeat expansions and SNVs/indels in the FMR1 gene at single-nucleotide resolution by combining Xdrop enrichment with two next-generation sequencing approaches. With the appropriate optimization necessary for the clinical settings, the system could facilitate both the study of genotype-phenotype correlation in FXS and enable a more efficient diagnosis and genetic counseling for patients and their relatives.
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Affiliation(s)
- Valentina Grosso
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Luca Marcolungo
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Simone Maestri
- Department of Biotechnology, University of Verona, Verona, Italy
| | | | - Denise Lavezzari
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Barbara Iadarola
- Department of Biotechnology, University of Verona, Verona, Italy
| | - Alessandro Salviati
- Department of Biotechnology, University of Verona, Verona, Italy
- GENARTIS srl, Verona, Italy
| | - Barbara Mariotti
- Department of Medicine, Section of General Pathology, University of Verona, Verona, Italy
| | - Annalisa Botta
- Department of Biomedicine and Prevention, Medical Genetics Section, University of Rome "Tor Vergata", Rome, Italy
| | | | - Giuseppe Novelli
- Department of Biomedicine and Prevention, Medical Genetics Section, University of Rome "Tor Vergata", Rome, Italy
- IRCCS Neuromed Mediterranean Neurological Institute, Pozzilli, Italy
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Massimo Delledonne
- Department of Biotechnology, University of Verona, Verona, Italy
- GENARTIS srl, Verona, Italy
| | - Marzia Rossato
- Department of Biotechnology, University of Verona, Verona, Italy
- GENARTIS srl, Verona, Italy
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19
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Barragan AC, Weigel D. Plant NLR diversity: the known unknowns of pan-NLRomes. THE PLANT CELL 2021; 33:814-831. [PMID: 33793812 PMCID: PMC8226294 DOI: 10.1093/plcell/koaa002] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/23/2020] [Indexed: 05/20/2023]
Abstract
Plants and pathogens constantly adapt to each other. As a consequence, many members of the plant immune system, and especially the intracellular nucleotide-binding site leucine-rich repeat receptors, also known as NOD-like receptors (NLRs), are highly diversified, both among family members in the same genome, and between individuals in the same species. While this diversity has long been appreciated, its true extent has remained unknown. With pan-genome and pan-NLRome studies becoming more and more comprehensive, our knowledge of NLR sequence diversity is growing rapidly, and pan-NLRomes provide powerful platforms for assigning function to NLRs. These efforts are an important step toward the goal of comprehensively predicting from sequence alone whether an NLR provides disease resistance, and if so, to which pathogens.
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Affiliation(s)
- A Cristina Barragan
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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20
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Blondal T, Gamba C, Møller Jagd L, Su L, Demirov D, Guo S, Johnston CM, Riising EM, Wu X, Mikkelsen MJ, Szabova L, Mouritzen P. Verification of CRISPR editing and finding transgenic inserts by Xdrop indirect sequence capture followed by short- and long-read sequencing. Methods 2021; 191:68-77. [PMID: 33582298 DOI: 10.1016/j.ymeth.2021.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 11/12/2020] [Accepted: 02/02/2021] [Indexed: 01/02/2023] Open
Abstract
Validation of CRISPR-Cas9 editing typically explores the immediate vicinity of the gene editing site and distal off-target sequences, which has led to the conclusion that CRISPR-Cas9 editing is very specific. However, an increasing number of studies suggest that on-target unintended editing events like deletions and insertions are relatively frequent but unfortunately often missed in the validation of CRISPR-Cas9 editing. The deletions may be several kilobases-long and only affect one allele. The gold standard in molecular validation of gene editing is direct sequencing of relatively short PCR amplicons. This approach allows the detection of small editing events but fails in detecting large rearrangements, in particular when only one allele is affected. Detection of large rearrangements requires that an extended region is analyzed and the characterization of events may benefit from long-read sequencing. Here we implemented Xdrop™, a new microfluidic technology that allows targeted enrichment of long regions (~100 kb) using just a single standard PCR primer set. Sequencing of the enriched CRISPR-Cas9 gene-edited region in four cell lines on long- and short-read sequencing platforms unravelled unknown and unintended genome editing events. The analysis revealed accidental kilobases-large insertions in three of the cell lines, which remained undetected using standard procedures. We also applied the targeted enrichment approach to identify the integration site of a transgene in a mouse line. The results demonstrate the potential of this technology in gene editing validation as well as in more classic transgenics.
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Affiliation(s)
| | | | | | - Ling Su
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Dimiter Demirov
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Shuang Guo
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | | | | | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | | | - Ludmila Szabova
- Center for Advanced Preclinical Research, Frederick National Laboratory for Cancer Research at the National Cancer Institute-Frederick, Frederick, MD, USA
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21
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Emeriewen OF, Richter K, Flachowsky H, Malnoy M, Peil A. Genetic Analysis and Fine Mapping of the Fire Blight Resistance Locus of Malus ×arnoldiana on Linkage Group 12 Reveal First Candidate Genes. FRONTIERS IN PLANT SCIENCE 2021; 12:667133. [PMID: 33959143 PMCID: PMC8093435 DOI: 10.3389/fpls.2021.667133] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/24/2021] [Indexed: 05/03/2023]
Abstract
Malus ×arnoldiana accession MAL0004 has been found to be resistant to moderately and highly virulent strains of the fire blight causal pathogen - the Gram-negative bacterium, Erwinia amylovora. Genetic analyses with an F1 segregating population derived from crossing the highly susceptible apple cultivar 'Idared' and MAL0004 led to the detection and mapping of the fire blight resistance locus of M. ×arnoldiana to linkage group (LG)12 (FB_Mar12). FB_Mar12 mapped at the distal end of LG12 below the apple SSR Hi07f01 in an interval of approximately 6 cM (Centimorgan), where both the fire blight resistance loci of M. floribunda 821 and 'Evereste' were located. We fine mapped the region containing FB_Mar12 using 892 progenies. Mining of the region of interest (ROI) on the 'Golden Delicious' doubled haploid genome (GDDH13) identified the presence of 2.3 Mb (megabases) in the homologous region. Of 40 primer pairs designed within this region, 20 were polymorphic and nine were mapped, leading to the identification of 24 significant recombinant individuals whose phenotypes were informative in determining the precise position of the locus within a 0.57 cM interval. Analyses of tightly linked marker sequences on the M. baccata draft genome revealed scaffolds of interest putatively harboring the resistance loci of M. ×arnoldiana, a hybrid between M. baccata and M. floribunda. Open reading frame (ORF) analyses led to the prediction of first fire blight resistance candidate genes with serine/threonine kinase and leucine-rich repeat domains, including homologs of previously identified 'Evereste' candidate genes. We discuss the implications of these results on breeding for resistance to fire blight.
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Affiliation(s)
- Ofere Francis Emeriewen
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Fruit Crops, Dresden, Germany
- Ofere Francis Emeriewen,
| | - Klaus Richter
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Quedlinburg, Germany
| | - Henryk Flachowsky
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Fruit Crops, Dresden, Germany
| | - Mickael Malnoy
- Research and Innovation Centre, Fondazione Edmund Mach (FEM), San Michele all’Adige, Italy
| | - Andreas Peil
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Fruit Crops, Dresden, Germany
- *Correspondence: Andreas Peil,
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22
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Maestri S, Maturo MG, Cosentino E, Marcolungo L, Iadarola B, Fortunati E, Rossato M, Delledonne M. A Long-Read Sequencing Approach for Direct Haplotype Phasing in Clinical Settings. Int J Mol Sci 2020; 21:E9177. [PMID: 33271988 PMCID: PMC7731377 DOI: 10.3390/ijms21239177] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/20/2020] [Accepted: 11/27/2020] [Indexed: 11/17/2022] Open
Abstract
The reconstruction of individual haplotypes can facilitate the interpretation of disease risks; however, high costs and technical challenges still hinder their assessment in clinical settings. Second-generation sequencing is the gold standard for variant discovery but, due to the production of short reads covering small genomic regions, allows only indirect haplotyping based on statistical methods. In contrast, third-generation methods such as the nanopore sequencing platform developed by Oxford Nanopore Technologies (ONT) generate long reads that can be used for direct haplotyping, with fewer drawbacks. However, robust standards for variant phasing in ONT-based target resequencing efforts are not yet available. In this study, we presented a streamlined proof-of-concept workflow for variant calling and phasing based on ONT data in a clinically relevant 12-kb region of the APOE locus, a hotspot for variants and haplotypes associated with aging-related diseases and longevity. Starting with sequencing data from simple amplicons of the target locus, we demonstrated that ONT data allow for reliable single-nucleotide variant (SNV) calling and phasing from as little as 60 reads, although the recognition of indels is less efficient. Even so, we identified the best combination of ONT read sets (600) and software (BWA/Minimap2 and HapCUT2) that enables full haplotype reconstruction when both SNVs and indels have been identified previously using a highly-accurate sequencing platform. In conclusion, we established a rapid and inexpensive workflow for variant phasing based on ONT long reads. This allowed for the analysis of multiple samples in parallel and can easily be implemented in routine clinical practice, including diagnostic testing.
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Affiliation(s)
| | | | | | | | | | | | - Marzia Rossato
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (S.M.); (M.G.M.); (E.C.); (L.M.); (B.I.); (E.F.); (M.D.)
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23
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Abstract
Understanding the evolution of sex determination mechanisms and sex chromosomes is of fundamental importance in biology. Here we have reconstructed the evolution of the sex-determining region in the Atlantic herring. The region is small and contains only three intact genes. The candidate sex-determining factor BMPR1BBY is an evolutionary innovation in the herring lineage. It encodes a truncated form of a BMP type I receptor, which originated by gene duplication and underwent rapid protein evolution. The receptor has maintained its kinase activity and has the potential to induce development of testis. The other two genes in the sex-determining region, CATSPERG and CATSPER3Y, are male beneficial genes because they encode proteins predicted to be essential for sperm to fertilize the egg. The mechanisms underlying sex determination are astonishingly plastic. Particularly the triggers for the molecular machinery, which recalls either the male or female developmental program, are highly variable and have evolved independently and repeatedly. Fish show a huge variety of sex determination systems, including both genetic and environmental triggers. The advent of sex chromosomes is assumed to stabilize genetic sex determination. However, because sex chromosomes are notoriously cluttered with repetitive DNA and pseudogenes, the study of their evolution is hampered. Here we reconstruct the birth of a Y chromosome present in the Atlantic herring. The region is tiny (230 kb) and contains only three intact genes. The candidate male-determining gene BMPR1BBY encodes a truncated form of a BMP1B receptor, which originated by gene duplication and translocation and underwent rapid protein evolution. BMPR1BBY phosphorylates SMADs in the absence of ligand and thus has the potential to induce testis formation. The Y region also contains two genes encoding subunits of the sperm-specific Ca2+ channel CatSper required for male fertility. The herring Y chromosome conforms with a characteristic feature of many sex chromosomes, namely, suppressed recombination between a sex-determining factor and genes that are beneficial for the given sex. However, the herring Y differs from other sex chromosomes in that suppression of recombination is restricted to an ∼500-kb region harboring the male-specific and sex-associated regions. As a consequence, any degeneration on the herring Y chromosome is restricted to those genes located in the small region affected by suppressed recombination.
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24
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Madsen EB, Höijer I, Kvist T, Ameur A, Mikkelsen MJ. Xdrop: Targeted sequencing of long DNA molecules from low input samples using droplet sorting. Hum Mutat 2020; 41:1671-1679. [PMID: 32516842 PMCID: PMC7496172 DOI: 10.1002/humu.24063] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 04/29/2020] [Accepted: 06/05/2020] [Indexed: 11/07/2022]
Abstract
Long-read sequencing can resolve regions of the genome that are inaccessible to short reads, and therefore are ideal for genome-gap closure, solving structural rearrangements and sequencing through repetitive elements. Here we introduce the Xdrop technology: a novel microfluidic-based system that allows for targeted enrichment of long DNA molecules starting from only a few nanograms of DNA. Xdrop is based on the isolation of long DNA fragments in millions of droplets, where the droplets containing a target sequence of interest are fluorescently labeled and sorted using flow cytometry. The final product from the Xdrop procedure is an enriched population of long DNA molecules that can be investigated by sequencing. To demonstrate the capability of Xdrop, we performed enrichment of the human papilloma virus 18 integrated into the genome of human HeLa cells. Analysis of the sequencing reads resolved three HPV18-chr8 integrations at base-pair resolution, and the captured fragments extended up to 30 kb into the human genome at the integration sites. Further, we enriched the complete TP53 locus in a leukemia cell line and could successfully phase coexisting mutations using PacBio sequencing. In summary, our results show that Xdrop is an efficient enrichment technology for studying complex genomic regions.
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Affiliation(s)
| | - Ida Höijer
- Science for Life Laboratory, Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
| | | | - Adam Ameur
- Science for Life Laboratory, Department of Immunology, Genetics and PathologyUppsala UniversityUppsalaSweden
- Department of Epidemiology and Preventive MedicineMonash UniversityMelbourneAustralia
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