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Hanlon VCT, Lansdorp PM, Guryev V. A survey of current methods to detect and genotype inversions. Hum Mutat 2022; 43:1576-1589. [PMID: 36047337 DOI: 10.1002/humu.24458] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/11/2022]
Abstract
Polymorphic inversions are ubiquitous in humans, and they have been linked to both adaptation and disease. Following their discovery in Drosophila more than a century ago, inversions have proved to be more elusive than other structural variants. A wide variety of methods for the detection and genotyping of inversions have recently been developed: multiple techniques based on selective amplification by PCR, short- and long-read sequencing approaches, principal component analysis of small variant haplotypes, template strand sequencing, optical mapping, and various genome assembly methods. Many methods apply complex wet lab protocols or increasingly refined bioinformatic analyses. This review is an attempt to provide a practical summary and comparison of the methods that are in current use, with a focus on metrics such as the maximum size of segmental duplications at inversion breakpoints that each method can tolerate, the size range of inversions that they recover, their throughput, and whether the locations of putative inversions must be known beforehand. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Peter M Lansdorp
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, V5Z 1L3, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Victor Guryev
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, The Netherlands
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Xu JM, Zhu JS, Li MZ, Hu H, Mao CZ. Progress on methods for acquiring flanking genomic sequence. Yi Chuan 2022; 44:313-321. [PMID: 35437239 DOI: 10.16288/j.yczz.21-415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Flanking genomic sequences refer to the DNA sequences flanking specific sites of known sequences in chromosome, which contain information such as candidate genes, transcriptional regulation, chromosome structure, and biosafety, and play an important role in genomics research. Flanking sequence acquisition technologies are mainly used in the cloning of regulatory sequences such as promoters and enhancers, identification of T-DNA or transposon insertion sites, chromosome walking, genome-wide gap filling, etc. It is an important means of structural genomics research and functional genomics research. It is applied in the identification of transgenic plants and animals and their safety management. With the development of molecular biology, many methods for obtaining flanking sequences have been established, including plasmid rescue, inverse PCR, ligation-mediated PCR, semi-random primer PCR, whole-genome resequencing etc. In this review, we summarize and compared different methods for acquiring flanking genomic sequence. The principles and research progress of each approach are discussed.
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Affiliation(s)
- Ji-Ming Xu
- Institute of Plant Biology, College of Life Science, Zhejiang University, Hangzhou 310058, China
| | - Jian-Shu Zhu
- Institute of Plant Biology, College of Life Science, Zhejiang University, Hangzhou 310058, China
| | - Meng-Zhen Li
- Institute of Plant Biology, College of Life Science, Zhejiang University, Hangzhou 310058, China
| | - Han Hu
- Institute of Plant Biology, College of Life Science, Zhejiang University, Hangzhou 310058, China
| | - Chuan-Zao Mao
- Institute of Plant Biology, College of Life Science, Zhejiang University, Hangzhou 310058, China
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Hogan AM, Jeffers KR, Palacios A, Cardona ST. Improved Dynamic Range of a Rhamnose-Inducible Promoter for Gene Expression in Burkholderia spp. Appl Environ Microbiol 2021; 87:e0064721. [PMID: 34190606 DOI: 10.1128/AEM.00647-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A diverse genetic toolkit is critical for understanding bacterial physiology and genotype-phenotype relationships. Inducible promoter systems are an integral part of this toolkit. In Burkholderia and related species, the l-rhamnose-inducible promoter is among the first choices due to its tight control and the lack of viable alternatives. To improve upon its maximum activity and dynamic range, we explored the effect of promoter system modifications in Burkholderia cenocepacia with a LacZ-based reporter. By combining the bacteriophage T7 gene 10 stem-loop and engineered rhaI transcription factor-binding sites, we obtained a rhamnose-inducible system with a 6.5-fold and 3.0-fold increases in maximum activity and dynamic range, respectively, compared to the native promoter. We then added the modified promoter system to pSCrhaB2 and pSC201, common genetic tools used for plasmid-based and chromosome-based gene expression, respectively, in Burkholderia, creating pSCrhaB2plus and pSC201plus. We demonstrated the utility of pSCrhaB2plus for gene expression in B. thailandensis, B. multivorans, and B. vietnamiensis and used pSC201plus to control highly expressed essential genes from the chromosome of B. cenocepacia. The utility of the modified system was demonstrated as we recovered viable mutants to control ftsZ, rpoBC, and rpsF, whereas the unmodified promoter was unable to control rpsF. The modified expression system allowed control of an essential gene depletion phenotype at lower levels of l-rhamnose, the inducer. pSCRhaB2plus and pSC201plus are expected to be valuable additions to the genetic toolkit for Burkholderia and related species. IMPORTANCE Species of Burkholderia are dually recognized as being of attractive biotechnological potential but also opportunistic pathogens for immunocompromised individuals. Understanding the genotype-phenotype relationship is critical for synthetic biology approaches in Burkholderia to disentangle pathogenic from beneficial traits. A diverse genetic toolkit, including inducible promoters, is the foundation for these investigations. Thus, we sought to improve on the commonly used rhamnose-inducible promoter system. Our modifications resulted in both higher levels of heterologous protein expression and broader control over highly expressed essential genes in B. cenocepacia. The significance of our work is in expanding the genetic toolkit to enable more comprehensive studies into Burkholderia and related bacteria.
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D'Angelo S, Ferrara F, Naranjo L, Erasmus MF, Hraber P, Bradbury ARM. Many Routes to an Antibody Heavy-Chain CDR3: Necessary, Yet Insufficient, for Specific Binding. Front Immunol 2018; 9:395. [PMID: 29568296 PMCID: PMC5852061 DOI: 10.3389/fimmu.2018.00395] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 02/13/2018] [Indexed: 12/11/2022] Open
Abstract
Because of its great potential for diversity, the immunoglobulin heavy-chain complementarity-determining region 3 (HCDR3) is taken as an antibody molecule’s most important component in conferring binding activity and specificity. For this reason, HCDR3s have been used as unique identifiers to investigate adaptive immune responses in vivo and to characterize in vitro selection outputs where display systems were employed. Here, we show that many different HCDR3s can be identified within a target-specific antibody population after in vitro selection. For each identified HCDR3, a number of different antibodies bearing differences elsewhere can be found. In such selected populations, all antibodies with the same HCDR3 recognize the target, albeit at different affinities. In contrast, within unselected populations, the majority of antibodies with the same HCDR3 sequence do not bind the target. In one HCDR3 examined in depth, all target-specific antibodies were derived from the same VDJ rearrangement, while non-binding antibodies with the same HCDR3 were derived from many different V and D gene rearrangements. Careful examination of previously published in vivo datasets reveals that HCDR3s shared between, and within, different individuals can also originate from rearrangements of different V and D genes, with up to 26 different rearrangements yielding the same identical HCDR3 sequence. On the basis of these observations, we conclude that the same HCDR3 can be generated by many different rearrangements, but that specific target binding is an outcome of unique rearrangements and VL pairing: the HCDR3 is necessary, albeit insufficient, for specific antibody binding.
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Affiliation(s)
| | | | | | | | - Peter Hraber
- Los Alamos National Laboratory, Los Alamos, NM, United States
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Racher H, Soliman S, Argiropoulos B, Chan HSL, Gallie BL, Perrier R, Matevski D, Rushlow D, Piovesan B, Shaikh F, MacDonald H, Corson TW. Molecular analysis distinguishes metastatic disease from second cancers in patients with retinoblastoma. Cancer Genet 2016; 209:359-63. [PMID: 27318443 DOI: 10.1016/j.cancergen.2016.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/25/2016] [Accepted: 06/02/2016] [Indexed: 12/17/2022]
Abstract
The pediatric ocular tumor retinoblastoma readily metastasizes, but these lesions can masquerade as histologically similar pediatric small round blue cell tumors. Since 98% of retinoblastomas have RB1 mutations and a characteristic genomic copy number "signature", genetic analysis is an appealing adjunct to histopathology to distinguish retinoblastoma metastasis from second primary cancer in retinoblastoma patients. Here, we describe such an approach in two retinoblastoma cases. In patient one, allele-specific (AS)-PCR for a somatic nonsense mutation confirmed that a temple mass was metastatic retinoblastoma. In a second patient, a rib mass shared somatic copy number gains and losses with the primary tumor. For definitive diagnosis, however, an RB1 mutation was needed, but heterozygous promoter→exon 11 deletion was the only RB1 mutation detected in the primary tumor. We used a novel application of inverse PCR to identify the deletion breakpoint. Subsequently, AS-PCR designed for the breakpoint confirmed that the rib mass was metastatic retinoblastoma. These cases demonstrate that personalized molecular testing can confirm retinoblastoma metastases and rule out a second primary cancer, thereby helping to direct the clinical management.
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Affiliation(s)
- Hilary Racher
- Impact Genetics, Bowmanville, Ontario L1C 3K5, Canada
| | - Sameh Soliman
- Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada; Ophthalmology Department, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Bob Argiropoulos
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Helen S L Chan
- Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Brenda L Gallie
- Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Renée Perrier
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | | | - Diane Rushlow
- Impact Genetics, Bowmanville, Ontario L1C 3K5, Canada
| | | | - Furqan Shaikh
- Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | | | - Timothy W Corson
- Eugene and Marilyn Glick Eye Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Kim S, Park YJ, Kim J. Inverse PCR for subtyping of Acinetobacter baumannii carrying ISAba1. J Microbiol 2016; 54:376-80. [PMID: 27095456 DOI: 10.1007/s12275-016-6038-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 10/21/2022]
Abstract
Acinetobacter baumannii has been prevalent in nosocomial infections, often causing outbreaks in intensive care units. ISAba1 is an insertion sequence that has been identified only in A. baumannii and its copy number varies among strains. It has been reported that ISAba1 provides a promoter for bla(OXA-51-like), bla(OXA-23-like), and bla(ampC), which are associated with the resistance of A. baumannii to carbapenems and cephalosporins. The main purpose of this study was to develop a novel inverse PCR method capable of typing A. baumannii strains. The method involves three major steps: cutting of genomic DNA with a restriction enzyme, ligation, and PCR. In the first step, bacterial genomic DNA was digested with DpnI. In the second step, the digested genomic DNAs were ligated to form intramolecular circular DNAs. In the last step, the ligated circular DNAs were amplified by PCR with primers specific for ISAba1 and the amplified PCR products were electrophoresed. Twenty-two clinical isolates of A. baumannii were used for the evaluation of the inverse PCR (iPCR) typing method. Dendrogram analysis revealed two major clusters, similar to pulsed-field gel electrophoresis (PFGE) results. Three ISAba1-associated genes--bla(ampC), bla(OXA-66-like), and csuD--were amplified and detected in the clinical isolates. This novel iPCR typing method is comparable to PFGE in its ability to discriminate A. baumannii strains, and is a promising molecular epidemiological tool for investigating A. baumannii carrying ISAba1.
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Nakamura Y, Ando Y, Takagi Y, Murata M, Kozuka T, Nakata Y, Hasebe R, Takagi A, Matsushita T, Shima M, Kojima T. Distinct X chromosomal rearrangements in four haemophilia B patients with entire F9 deletion. Haemophilia 2015; 22:433-9. [PMID: 26686734 DOI: 10.1111/hae.12849] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/09/2015] [Accepted: 09/14/2015] [Indexed: 01/31/2023]
Abstract
INTRODUCTION Haemophilia B is an X-linked bleeding disorder caused by a coagulation factor IX gene (F9) abnormality. Numerous F9 defects have been identified to date; however, only a few with an entire F9 deletion have been reported in detail. AIM To elucidate the cause of severe haemophilia B, we investigated the precise X chromosome abnormalities in four Japanese patients who did not show all amplifications in F9-specific PCR. METHODS We analysed the patient's genomic DNA using Multiplex ligation-dependent probe amplification (MLPA). To assess the extent of any deletions, we further performed mapping PCRs, inverse PCRs or long-range PCRs and direct sequencing analyses of the X chromosome. RESULTS We detected entire F9 deletions in four haemophilia B patients and identified the precise deleted regions of the X chromosome including F9. Patient 1 had a 149-kb deletion with breakpoints 90-kb upstream and 30-kb downstream from F9. Patients 2 and 3 showed 273-kb and 1.19-Mb deletions respectively. Patient 4 had two deleted regions: a 1663-bp deletion 1.34-Mb upstream from F9 and a 7.2-Mb deletion including F9. These distinct breakpoints found in four different patients suggest that the mechanism of X chromosome deletion may be different between individuals. Non-allelic homologous recombination (NAHR), microhomology-mediated break-induced replication (MMBIR) or fork stalling and template switching (FoSTeS) may occur in respective X chromosomes of the four haemophilia B patients analysed. CONCLUSIONS We identified diverse X chromosomal rearrangements in four haemophilia B patients, which might be caused by distinct mechanisms of genomic rearrangement.
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Affiliation(s)
- Y Nakamura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Ando
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Takagi
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - M Murata
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
| | - T Kozuka
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Nakata
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - R Hasebe
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - A Takagi
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - T Matsushita
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan
| | - M Shima
- Department of Paediatric, Nara Medical University, Nara, Japan
| | - T Kojima
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Abstract
The application of deep sequencing to in vitro display technologies has been invaluable for the straightforward analysis of enriched clones. After sequencing in vitro selected populations, clones are binned into identical or similar groups and ordered by abundance, allowing identification of those that are most enriched. However, the greatest strength of deep sequencing is also its greatest weakness: clones are easily identified by their DNA sequences, but are not physically available for testing without a laborious multistep process involving several rounds of polymerization chain reaction (PCR), assembly and cloning. Here, using the isolation of antibody genes from a phage and yeast display selection as an example, we show the power of a rapid and simple inverse PCR-based method to easily isolate clones identified by deep sequencing. Once primers have been received, clone isolation can be carried out in a single day, rather than two days. Furthermore the reduced number of PCRs required will reduce PCR mutations correspondingly. We have observed a 100% success rate in amplifying clones with an abundance as low as 0.5% in a polyclonal population. This approach allows us to obtain full-length clones even when an incomplete sequence is available, and greatly simplifies the subcloning process. Moreover, rarer, but functional clones missed by traditional screening can be easily isolated using this method, and the approach can be extended to any selected library (scFv, cDNA, libraries based on scaffold proteins) where a unique sequence signature for the desired clones of interest is available.
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Affiliation(s)
| | - Sandeep Kumar
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA Present address: Compugen USA, Inc., San Francisco, CA 94080, USA
| | - Leslie Naranjo
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | | | - Csaba Kiss
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, USA
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