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Elias M, Guan X, Hudson D, Bose R, Kwak J, Petrounia I, Touah K, Mansour S, Yue P, Errasti G, Delacroix T, Ghosh A, Chakrabarti R. Evolution of Organic Solvent-Resistant DNA Polymerases. ACS Synth Biol 2023; 12:3170-3188. [PMID: 37611245 DOI: 10.1021/acssynbio.2c00515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The introduction of thermostable polymerases revolutionized the polymerase chain reaction (PCR) and biotechnology. However, many GC-rich genes cannot be PCR-amplified with high efficiency in water, irrespective of temperature. Although polar organic cosolvents can enhance nucleic acid polymerization and amplification by destabilizing duplex DNA and secondary structures, nature has not selected for the evolution of solvent-tolerant polymerase enzymes. Here, we used ultrahigh-throughput droplet-based selection and deep sequencing along with computational free-energy and binding affinity calculations to evolve Taq polymerase to generate enzymes that are both stable and highly active in the presence of organic cosolvents, resulting in up to 10% solvent resistance and over 100-fold increase in stability at 97.5 °C in the presence of 1,4-butanediol, as well as tolerance to up to 10 times higher concentrations of the potent cosolvents sulfolane and 2-pyrrolidone. Using these polymerases, we successfully amplified a broad spectrum of GC-rich templates containing regions with over 90% GC content, including templates recalcitrant to amplification with existing polymerases, even in the presence of cosolvents. We also demonstrated dramatically reduced GC bias in the amplification of genes with widely varying GC content in quantitative polymerase chain reaction (qPCR). By expanding the scope of solvent systems compatible with nucleic acid polymerization, these organic solvent-resistant polymerases enable a dramatic reduction of sequence bias not achievable through thermal resistance alone, with significant implications for a wide range of applications including sequencing and synthetic biology in mixed aqueous-organic media.
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Affiliation(s)
- Mohammed Elias
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Xiangying Guan
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Devin Hudson
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Rahul Bose
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Joon Kwak
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Ioanna Petrounia
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Kenza Touah
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Sourour Mansour
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Peng Yue
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
| | - Gauthier Errasti
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Thomas Delacroix
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
| | - Anisha Ghosh
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
- McGill University, 845 Rue Sherbrooke Ouest, Montreal, QC H3A 0G4, Canada
| | - Raj Chakrabarti
- Chakrabarti Advanced Technology, LLC, PMC Group Building, 1288 Route 73, Suite 110, Mount Laurel, New Jersey 08054, United States
- Center for Protein Engineering & Drug Discovery, PMC Isochem SAS, 32 Rue Lavoisier, Vert-Le-Petit 91710, France
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Liu Y, Wang X, Li Y, Wu H. An all-in-one strategy for bisulfite-free DNA methylation detection by temperature-programmed enzymatic reactions. Anal Chim Acta 2023; 1251:341001. [PMID: 36925290 DOI: 10.1016/j.aca.2023.341001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 02/08/2023] [Accepted: 02/21/2023] [Indexed: 02/24/2023]
Abstract
The fragmentation and low concentration of cell-free DNA (cfDNA) pose higher challenges for the cfDNA methylation detection technologies. Conventional bisulfite conversion-based methods are inadequate for cfDNA methylation analysis due to cumbersome operation and exacerbating cfDNA degradation. Herein, we proposed temperature-programmed enzymatic reactions for cfDNA methylation analysis in a single tube. Endonuclease was used to mildly recognize DNA methylation to avoid the degradation of cfDNA. And two stages of amplification reactions significantly improved the detection sensitivity for GC-rich sequence. With vimentin as the target, the detection sensitivity was 10 copies of methylated DNA. Meanwhile, the proposed method can accurately quantify the methylation level of target sequence from 1000-fold of unmethylated DNA background. Further, the methylated vimentin gene in 20 clinical plasma samples was successfully detected. The results shown significant differences in methylation levels of the vimentin gene between healthy volunteers and colorectal cancer patients. These results lead us to believe that the proposed method has great application potential for DNA methylation analysis as a complement to bisulfite conversion-based methods.
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Affiliation(s)
- Yunlong Liu
- State Key Laboratory of Natural Medicines, Department of Biomedical Engineering, School of Engineering, China Pharmaceutical University, Nanjing, 211198, PR China.
| | - Xiaoming Wang
- Department of Clinical Laboratory, The Affiliated Cancer Hospital of Nanjing Medical University & Jiangsu Cancer Hospital & Jiangsu Institute of Cancer Research, Nanjing, 210009, PR China
| | - Yujiao Li
- Department of Pharmacology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China
| | - Haiping Wu
- Department of Pharmacology, Jinling Hospital, Medical School of Nanjing University, Nanjing, 210002, PR China; School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, 510515, PR China.
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3
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Hervouet K, Ferrié M, Ankavay M, Montpellier C, Camuzet C, Alexandre V, Dembélé A, Lecoeur C, Foe AT, Bouquet P, Hot D, Vausselin T, Saliou JM, Salomé-Desnoulez S, Vandeputte A, Marsollier L, Brodin P, Dreux M, Rouillé Y, Dubuisson J, Aliouat-Denis CM, Cocquerel L. An Arginine-Rich Motif in the ORF2 capsid protein regulates the hepatitis E virus lifecycle and interactions with the host cell. PLoS Pathog 2022; 18:e1010798. [PMID: 36007070 PMCID: PMC9451086 DOI: 10.1371/journal.ppat.1010798] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/07/2022] [Accepted: 08/06/2022] [Indexed: 11/18/2022] Open
Abstract
Hepatitis E virus (HEV) infection is the most common cause of acute viral hepatitis worldwide. Hepatitis E is usually asymptomatic and self-limiting but it can become chronic in immunocompromised patients and is associated with increased fulminant hepatic failure and mortality rates in pregnant women. HEV genome encodes three proteins including the ORF2 protein that is the viral capsid protein. Interestingly, HEV produces 3 isoforms of the ORF2 capsid protein which are partitioned in different subcellular compartments and perform distinct functions in the HEV lifecycle. Notably, the infectious ORF2 (ORF2i) protein is the structural component of virions, whereas the genome-free secreted and glycosylated ORF2 proteins likely act as a humoral immune decoy. Here, by using a series of ORF2 capsid protein mutants expressed in the infectious genotype 3 p6 HEV strain as well as chimeras between ORF2 and the CD4 glycoprotein, we demonstrated how an Arginine-Rich Motif (ARM) located in the ORF2 N-terminal region controls the fate and functions of ORF2 isoforms. We showed that the ARM controls ORF2 nuclear translocation likely to promote regulation of host antiviral responses. This motif also regulates the dual topology and functionality of ORF2 signal peptide, leading to the production of either cytosolic infectious ORF2i or reticular non-infectious glycosylated ORF2 forms. It serves as maturation site of glycosylated ORF2 by furin, and promotes ORF2-host cell membrane interactions. The identification of ORF2 ARM as a unique central regulator of the HEV lifecycle uncovers how viruses settle strategies to condense their genetic information and hijack cellular processes.
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Affiliation(s)
- Kévin Hervouet
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Martin Ferrié
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Maliki Ankavay
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
- Division of Gastroenterology and Hepatology, Institute of Microbiology, Lausanne, Switzerland
| | - Claire Montpellier
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Charline Camuzet
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Virginie Alexandre
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Aïcha Dembélé
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Cécile Lecoeur
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Arnold Thomas Foe
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Peggy Bouquet
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - David Hot
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - Thibaut Vausselin
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Jean-Michel Saliou
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - Sophie Salomé-Desnoulez
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - Alexandre Vandeputte
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - Laurent Marsollier
- Université d’Angers, Nantes Université, INSERM, Immunology and New Concepts in ImmunoTherapy, INCIT, UMR 1302, Angers, France
| | - Priscille Brodin
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 - US41 - PLBS-Plateformes Lilloises de Biologie & Santé, Lille, France
| | - Marlène Dreux
- CIRI - Centre International de Recherche en Infectiologie, Univ Lyon, Université Claude Bernard Lyon 1, Inserm-U1111, CNRS-UMR5308, ENS-Lyon, Lyon, France
| | - Yves Rouillé
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Jean Dubuisson
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Cécile-Marie Aliouat-Denis
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
| | - Laurence Cocquerel
- University of Lille, CNRS, INSERM, CHU Lille, Pasteur Institute of Lille, U1019-UMR 9017-CIIL- Center for Infection and Immunity of Lille, Lille, France
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Disruptors, a new class of oligonucleotide reagents, significantly improved PCR performance on templates containing stable intramolecular secondary structures. Anal Biochem 2021; 624:114169. [PMID: 33766577 DOI: 10.1016/j.ab.2021.114169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 11/21/2022]
Abstract
Intramolecular secondary structures within templates have been shown to lower PCR performance. Whereas many approaches have been developed to mitigate such impairment on PCR, their effects can vary greatly depending on template sequences. Here we present a novel, universally effective approach to improve PCR performance involving specifically designed oligonucleotides called disruptors. A disruptor contained three functional components, an anchor designed to initiate template binding, an effector to disrupt intramolecular secondary structure, and a 3' blocker to prevent its elongation by DNA polymerase. A functional mechanism for a disruptor to improve PCR efficiency was proposed where anchor first binds to template followed by effector-mediated strand displacement to unwind intramolecular secondary structure. Such a mechanism was consistent with the observation that anchor played a more critical role for disruptor function. As an example of potential disruptor applications, inverted terminal repeat sequences of recombinant adeno-associated virus vectors were successfully amplified in the presence of disruptors despite their well-known reputation as some of the most difficult templates for PCR amplification and Sanger sequencing due to their ultra-stable T-shaped hairpin structures. In stark contrast, both DMSO and betaine, two PCR additives routinely used to facilitate PCR amplification and Sanger sequencing of GC-rich templates, did not demonstrate any improving effect.
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5
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Liu Z, Sun J, Zhao G, Xiong S, Ma Y, Zheng M. Transient stem-loop structure of nucleic acid template may interfere with polymerase chain reaction through endonuclease activity of Taq DNA polymerase. Gene 2020; 764:145095. [PMID: 32866587 DOI: 10.1016/j.gene.2020.145095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/18/2020] [Accepted: 08/24/2020] [Indexed: 12/14/2022]
Abstract
As a standard molecular biology technique, PCR uses DNA polymerase to detect, amplify and manipulate DNA targets. Due to its effect of exponential amplification, PCR can achieve high sensitivity required for detecting targets of low abundance. Therefore, it has become the method of choice for the majority of nucleic acid-based tests. In PCR reactions, DNA templates are first unwound into single strands, followed by a quick temperature drop when transient intramolecular secondary structures may form first within the single-stranded templates due to reaction kinetics. In this study, we showed that the adverse effects of stem-loop structures on PCR performance were directly correlated with their thermal stability. Moreover, fractions of intermediate PCR products of templates with stable stem-loop structures were significantly shorter than those without. It was further demonstrated that when encountering the duplex region of such a structure during the PCR extension step, the endonuclease activity of Taq DNA polymerase mediated by its 5'-3' exonuclease activity could digest template strand, resulting in stem-loop structure unwinding and subsequent completion of replication to produce truncated products. This work thus provided some new mechanistic insights into the complex nature of PCR assays, a frequently encountered but neglected aspect of this widely used technique.
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Affiliation(s)
- Zhaocheng Liu
- University of Science and Technology of China, Hefei, Anhui 230027, China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China
| | - Jinli Sun
- University of Science and Technology of China, Hefei, Anhui 230027, China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China
| | - Guodong Zhao
- Zhejiang University Kunshan Biotechnology Laboratory, Zhejiang University Kunshan Innovation Institute, Kunshan, Jiangsu 215300, China; Suzhou VersaBio Technologies Co. Ltd., Kunshan, Jiangsu 215300, China; State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu 210009, China
| | - Shangmin Xiong
- Zhejiang University Kunshan Biotechnology Laboratory, Zhejiang University Kunshan Innovation Institute, Kunshan, Jiangsu 215300, China; Suzhou VersaBio Technologies Co. Ltd., Kunshan, Jiangsu 215300, China.
| | - Yong Ma
- University of Science and Technology of China, Hefei, Anhui 230027, China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China.
| | - Minxue Zheng
- University of Science and Technology of China, Hefei, Anhui 230027, China; Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China.
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Yang F, Sun J, Luo H, Ren H, Zhou H, Lin Y, Han M, Chen B, Liao H, Brix S, Li J, Yang H, Kristiansen K, Zhong H. Assessment of fecal DNA extraction protocols for metagenomic studies. Gigascience 2020; 9:giaa071. [PMID: 32657325 PMCID: PMC7355182 DOI: 10.1093/gigascience/giaa071] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/24/2020] [Accepted: 06/11/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Shotgun metagenomic sequencing has improved our understanding of the human gut microbiota. Various DNA extraction methods have been compared to find protocols that robustly and most accurately reflect the original microbial community structures. However, these recommendations can be further refined by considering the time and cost demands in dealing with samples from very large human cohorts. Additionally, fungal DNA extraction performance has so far been little investigated. RESULTS We compared 6 DNA extraction protocols, MagPure Fast Stool DNA KF Kit B, Macherey Nagel™ NucleoSpin™®Soil kit, Zymo Research Quick-DNA™ Fecal/Soil Microbe kit, MOBIO DNeasy PowerSoil kit, the manual non-commercial protocol MetaHIT, and the recently published protocol Q using 1 microbial mock community (MMC) (containing 8 bacterial and 2 fungal strains) and fecal samples. All samples were manually extracted and subjected to shotgun metagenomics sequencing. Extracting DNA revealed high reproducibility within all 6 protocols, but microbial extraction efficiencies varied. The MMC results demonstrated that bead size was a determining factor for fungal and bacterial DNA yields. In human fecal samples, the MagPure bacterial extraction performed as well as the standardized protocol Q but was faster and more cost-effective. Extraction using the PowerSoil protocol resulted in a significantly higher ratio of gram-negative to gram-positive bacteria than other protocols, which might contribute to reported gut microbial differences between healthy adults. CONCLUSIONS We emphasize the importance of bead size selection for bacterial and fungal DNA extraction. More importantly, the performance of the novel protocol MP matched that of the recommended standardized protocol Q but consumed less time, was more cost-effective, and is recommended for further large-scale human gut metagenomic studies.
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Affiliation(s)
- Fangming Yang
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 101408, China
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
| | - Jihua Sun
- BGI Europe A/S, COBIS, 2200 Copenhagen, Denmark
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | - Huahui Ren
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Hongcheng Zhou
- China National Genebank, Jinsha Road, Dapeng District, Shenzhen 518120, China
| | - Yuxiang Lin
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
| | - Mo Han
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Bing Chen
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
| | - Hailong Liao
- China National Genebank, Jinsha Road, Dapeng District, Shenzhen 518120, China
| | - Susanne Brix
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Junhua Li
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Huanming Yang
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- James D. Watson Institute of Genome Sciences, Hangzhou 310058, China
| | - Karsten Kristiansen
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Huanzi Zhong
- BGI-Shenzhen, Bei Shan Industrial Area, Yantian, Shenzhen 518083, China
- Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
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Shamim U, Ambawat S, Singh J, Thomas A, Pradeep-Chandra-Reddy C, Suroliya V, Uppilli B, Parveen S, Sharma P, Chanchal S, Nashi S, Preethish-Kumar V, Vengalil S, Polavarapu K, Keerthipriya M, Mahajan NP, Reddy N, Thomas PT, Sadasivan A, Warrier M, Seth M, Zahra S, Mathur A, Vibha D, Srivastava AK, Nalini A, Faruq M. C9orf72 hexanucleotide repeat expansion in Indian patients with ALS: a common founder and its geographical predilection. Neurobiol Aging 2020; 88:156.e1-156.e9. [PMID: 32035847 DOI: 10.1016/j.neurobiolaging.2019.12.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/27/2019] [Indexed: 12/16/2022]
Abstract
Hexanucleotide repeat expansion in C9orf72 is defined as a major causative factor for familial amyotrophic lateral sclerosis (ALS). The mutation frequency varies dramatically among populations of different ethnicity; however, in most cases, C9orf72 mutant has been described on a common founder haplotype. We assessed its frequency in a study cohort involving 593 clinically and electrophysiologically defined ALS cases. We also investigated the presence of reported Finnish haplotype among the mutation carriers. The identified common haplotype region was further screened in 192 (carrying 2-6 G4C2 repeats) and 96 (≥7 repeats) control chromosomes. The G4C2 expansion was observed in 3.2% (19/593) of total cases where 9/19 (47.4%) positive cases belonged to the eastern region of India. Haplotype analysis revealed 11 G4C2-Ex carriers shared the common haplotype (haplo-A) background spanning a region of ∼90 kbp (rs895021-rs11789520) including rs3849942 (a well-known global at-risk loci with T allele for G4C2 expansion). The other 3 G4C2-Ex cases had a different haplotype (haplo-B) with core difference from haplo-A at G4C2-Ex flanking 31 kbp region between rs3849942 and rs11789520 SNPs (allele 'C' of rs3849942 which is a nonrisk allele). Out of other five G4C2-cases, four carried the risk allele T of rs3849942 while one harbored the non-risk allele. This study establishes the prevalence of C9orf72 expansion in Indian ALS cases providing further evidence for geographical predilection. The global core risk haplotype predominated C9orf72 expansion-positive ALS cases, yet the existence of a different haplotype suggests a second lineage (haplo B), which may have been derived from the Finnish core haplotype or may imply a unique haplotype among Asians. The association of risk haplotype with normal intermediate C9orf72 alleles reinforced its role in conferring instability to the C9orf72-G4C2 region. We thus present an effective support to interpret future burden of ALS cases in India.
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Affiliation(s)
- Uzma Shamim
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sakshi Ambawat
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Jyotsna Singh
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Aneesa Thomas
- Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | | | - Varun Suroliya
- Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Bharathram Uppilli
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shaista Parveen
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Pooja Sharma
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shankar Chanchal
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Saraswati Nashi
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Seena Vengalil
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Kiran Polavarapu
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Muddasu Keerthipriya
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Neeraja Reddy
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Priya Treesa Thomas
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Arun Sadasivan
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Manjusha Warrier
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Malika Seth
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Sana Zahra
- Department of Psychiatric Social Work, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Deepti Vibha
- Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Achal K Srivastava
- Department of Neurology, Neuroscience Centre, All India Institute of Medical Sciences, New Delhi, India
| | - Atchayaram Nalini
- Neurology Department, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine Division, CSIR - Institute of Genomics and Integrative Biology, New Delhi, India.
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Binding and Structural Properties of DNA Aptamers with VEGF-A-Mimic Activity. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 19:1145-1152. [PMID: 32059340 PMCID: PMC7016029 DOI: 10.1016/j.omtn.2019.12.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 12/04/2019] [Accepted: 12/23/2019] [Indexed: 12/27/2022]
Abstract
Vascular endothelial growth factors (VEGFs) are hypoxia-inducible secreted proteins to promote angiogenesis, in which VEGF-A is an important molecule that binds and activates VEGF receptor-1 (VEGFR-1) and VEGFR-2. In this study, two DNA aptamers, Apt01 and Apt02, were successfully isolated by alternating consecutive systematic evolution of ligands by exponential enrichment (SELEX) against VEGFR-1 and -2 using deep sequencing analysis in an early selection round. Their binding affinities for VEGFR-2 were lower than that of VEGFR-1, which is similar to that of VEGF-A. Structural analyses with the measurements of circular dichroism spectra and ultraviolet melting curve showed that Apt01 possessed the stem-loop structure in the molecule, whereas Apt02 formed G-quadruplex structures. In addition, Apt02 accelerated a tube formation of human umbilical vein endothelial cells faster than Apt01, which was affected by difference of binding affinity and nuclease resistance due to G-quadruplex structures. These results demonstrated that Apt02 might have a potential to function as an alternative to VEGF-A.
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9
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Choi YS, Edwards LO, DiBello A, Jose AM. Removing bias against short sequences enables northern blotting to better complement RNA-seq for the study of small RNAs. Nucleic Acids Res 2017; 45:e87. [PMID: 28180294 PMCID: PMC5449620 DOI: 10.1093/nar/gkx091] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 02/02/2017] [Indexed: 12/21/2022] Open
Abstract
Changes in small non-coding RNAs such as micro RNAs (miRNAs) can serve as indicators of disease and can be measured using next-generation sequencing of RNA (RNA-seq). Here, we highlight the need for approaches that complement RNA-seq, discover that northern blotting of small RNAs is biased against short sequences and develop a protocol that removes this bias. We found that multiple small RNA-seq datasets from the worm Caenorhabditis elegans had shorter forms of miRNAs that appear to be degradation products that arose during the preparatory steps required for RNA-seq. When using northern blotting during these studies, we discovered that miRNA-length probes can have ∼1000-fold bias against detecting even synthetic sequences that are 8 nt shorter. By using shorter probes and by performing hybridization and washes at low temperatures, we greatly reduced this bias to enable nearly equivalent detection of 24 to 14 nt RNAs. Our protocol can discriminate RNAs that differ by a single nucleotide and can detect specific miRNAs present in total RNA from C. elegans and pRNAs in total RNA from bacteria. This improved northern blotting is particularly useful to analyze products of RNA processing or turnover, and functional RNAs that are shorter than typical miRNAs.
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Affiliation(s)
- Yun S Choi
- Department of Cell Biology and Molecular Genetics, University of Maryland, College, Park, MD 20742, USA
| | - Lanelle O Edwards
- Department of Cell Biology and Molecular Genetics, University of Maryland, College, Park, MD 20742, USA
| | - Aubrey DiBello
- Department of Cell Biology and Molecular Genetics, University of Maryland, College, Park, MD 20742, USA
| | - Antony M Jose
- Department of Cell Biology and Molecular Genetics, University of Maryland, College, Park, MD 20742, USA
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10
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Hayward BE, Kumari D, Usdin K. Recent advances in assays for the fragile X-related disorders. Hum Genet 2017; 136:1313-1327. [PMID: 28866801 DOI: 10.1007/s00439-017-1840-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/24/2017] [Indexed: 12/17/2022]
Abstract
The fragile X-related disorders are a group of three clinical conditions resulting from the instability of a CGG-repeat tract at the 5' end of the FMR1 transcript. Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X-associated primary ovarian insufficiency (FXPOI) are disorders seen in carriers of FMR1 alleles with 55-200 repeats. Female carriers of these premutation (PM) alleles are also at risk of having a child who has an FMR1 allele with >200 repeats. Most of these full mutation (FM) alleles are epigenetically silenced resulting in a deficit of the FMR1 gene product, FMRP. This results in fragile X Syndrome (FXS), the most common heritable cause of intellectual disability and autism. The diagnosis and study of these disorders is challenging, in part because the detection of alleles with large repeat numbers has, until recently, been either time-consuming or unreliable. This problem is compounded by the mosaicism for repeat length and/or DNA methylation that is frequently seen in PM and FM carriers. Furthermore, since AGG interruptions in the repeat tract affect the risk that a FM allele will be maternally transmitted, the ability to accurately detect these interruptions in female PM carriers is an additional challenge that must be met. This review will discuss some of the pros and cons of some recently described assays for these disorders, including those that detect FMRP levels directly, as well as emerging technologies that promise to improve the diagnosis of these conditions and to be useful in both basic and translational research settings.
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Affiliation(s)
- Bruce E Hayward
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA
| | - Daman Kumari
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, Building 8, Room 2A19, National Institutes of Health, 8 Center Drive MSC 0830, Bethesda, MD, 20892, USA.
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11
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Ishihara S, Kotomura N, Yamamoto N, Ochiai H. Ligation-mediated PCR with a back-to-back adapter reduces amplification bias resulting from variations in GC content. Anal Biochem 2017; 531:37-44. [DOI: 10.1016/j.ab.2017.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 12/18/2022]
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12
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Riley C, Wheeler A. Assessing the Fragile X Syndrome Newborn Screening Landscape. Pediatrics 2017; 139:S207-S215. [PMID: 28814541 PMCID: PMC5599128 DOI: 10.1542/peds.2016-1159g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/24/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is the most common known inherited form of intellectual disability. Early identification is an important step in linking FXS individuals with appropriate and timely medical and social services. Newborn screening (NBS) is 1 approach that has been used for other conditions to facilitate early identification. METHODS A literature review was conducted to identify issues, barriers, challenges, and approaches to addressing challenges related to NBS for FXS. Search terms included: fragile X syndrome, FMR1, newborn screening, screening, and genetic testing. To supplement the literature review, 9 key informant interviews were conducted. Information gathered through these interviews supplemented what was identified in the literature. Information from both the literature review and supplemental interviews was reviewed by 3 researchers who discussed and came to consensus on thematic areas and categorization of issues. RESULTS The barriers and challenges related to NBS for FXS identified in the literature and by experts and stakeholders are categorized into 5 thematic areas: public health burden, treatment, timing, screening/testing methodologies, and translating results. Summaries of these issues and barriers are provided, along with potential approaches to addressing them. CONCLUSIONS The issues and barriers described in this article highlight limited areas of knowledge that need be addressed to improve our understanding of FXS and the potential benefit of NBS. The landscape of NBS for FXS could be influenced by a series of research findings over time or a larger breakthrough that demonstrates an effective targeted treatment that has to be implemented early in life.
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Affiliation(s)
- Catharine Riley
- National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Anne Wheeler
- RTI International, Research Triangle Park, North Carolina
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13
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Hinz L, Ahles A, Ruprecht B, Küster B, Engelhardt S. Two serines in the distal C-terminus of the human ß1-adrenoceptor determine ß-arrestin2 recruitment. PLoS One 2017; 12:e0176450. [PMID: 28472170 PMCID: PMC5417508 DOI: 10.1371/journal.pone.0176450] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 04/11/2017] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptors (GPCRs) undergo phosphorylation at several intracellular residues by G protein-coupled receptor kinases. The resulting phosphorylation pattern triggers arrestin recruitment and receptor desensitization. The exact sites of phosphorylation and their function remained largely unknown for the human β1-adrenoceptor (ADRB1), a key GPCR in adrenergic signal transduction and the target of widely used drugs such as β-blockers. The present study aimed to identify the intracellular phosphorylation sites in the ADRB1 and to delineate their function. The human ADRB1 was expressed in HEK293 cells and its phosphorylation pattern was determined by mass spectrometric analysis before and after stimulation with a receptor agonist. We identified a total of eight phosphorylation sites in the receptor's third intracellular loop and C-terminus. Analyzing the functional relevance of individual sites using phosphosite-deficient receptor mutants we found phosphorylation of the ADRB1 at Ser461/Ser462 in the distal part of the C-terminus to determine β-arrestin2 recruitment and receptor internalization. Our data reveal the phosphorylation pattern of the human ADRB1 and the site that mediates recruitment of β-arrestin2.
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Affiliation(s)
- Laura Hinz
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
| | - Andrea Ahles
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
- * E-mail: (AA); (SE)
| | - Benjamin Ruprecht
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center for Protein Science Munich (CIPSM), Freising, Germany
| | - Bernhard Küster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center for Protein Science Munich (CIPSM), Freising, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- Bavarian Biomolecular Mass Spectrometry Center, Technical University of Munich, Freising, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany
- * E-mail: (AA); (SE)
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14
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Biasiotto G, Archetti S, Di Lorenzo D, Merola F, Paiardi G, Borroni B, Alberici A, Padovani A, Filosto M, Bonvicini C, Caimi L, Zanella I. A PCR-based protocol to accurately size C9orf72 intermediate-length alleles. Mol Cell Probes 2016; 32:60-64. [PMID: 27765650 DOI: 10.1016/j.mcp.2016.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 10/15/2016] [Accepted: 10/16/2016] [Indexed: 12/13/2022]
Abstract
Although large expansions of the non-coding GGGGCC repeat in C9orf72 gene are clearly defined as pathogenic for Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD), intermediate-length expansions have also been associated with those and other neurodegenerative diseases. Intermediate-length allele sizing is complicated by intrinsic properties of current PCR-based methodologies, in that somatic mosaicism could be suspected. We designed a protocol that allows the exact sizing of intermediate-length alleles, as well as the identification of large expansions.
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Affiliation(s)
- Giorgio Biasiotto
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy; Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Silvana Archetti
- Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Diego Di Lorenzo
- Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Francesca Merola
- Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Giulia Paiardi
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy; Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Barbara Borroni
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Neurology Unit, Centre for Aging Brain and Neurodegenerative Diseases, Civic Hospital of Brescia, Brescia, Italy
| | - Antonella Alberici
- Neurology Unit, Centre for Aging Brain and Neurodegenerative Diseases, Civic Hospital of Brescia, Brescia, Italy
| | - Alessandro Padovani
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Neurology Unit, Centre for Aging Brain and Neurodegenerative Diseases, Civic Hospital of Brescia, Brescia, Italy
| | - Massimiliano Filosto
- Neurology Unit, Centre for Neuromuscular Diseases and Neuropathies, Civic Hospital of Brescia, Brescia, Italy
| | | | - Luigi Caimi
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy; Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy
| | - Isabella Zanella
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy; Biotechnology Laboratory, Department of Diagnostics, Civic Hospital of Brescia, Brescia, Italy.
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15
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Flores-Juárez CR, González-Jasso E, Antaramian A, Pless RC. PCR amplification of GC-rich DNA regions using the nucleotide analog N4-methyl-2'-deoxycytidine 5'-triphosphate. Biotechniques 2016; 61:175-182. [PMID: 27712580 DOI: 10.2144/000114457] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/06/2016] [Indexed: 11/23/2022] Open
Abstract
GC-rich DNA regions were PCR-amplified with Taq DNA polymerase using either the canonical set of deoxynucleoside triphosphates or mixtures in which the dCTP had been partially or completely replaced by its N4-methylated analog, N4-methyl-2'-deoxycytidine 5'-triphosphate (N4me-dCTP). In the case of a particularly GC-rich region (78.9% GC), the PCR mixtures containing N4me-dCTP produced the expected amplicon in high yield, while mixtures containing the canonical set of nucleotides produced numerous alternative amplicons. For another GC-rich DNA region (80.6% GC), the target amplicon was only generated by re-amplifying a gel-purified sample of the original amplicon with N4me-dCTP-containing PCR mixtures. In a direct PCR comparison on a highly GC-rich template, mixtures containing N4me-dCTP clearly performed better than did solutions containing the canonical set of nucleotides mixed with various organic additives (DMSO, betaine, or ethylene glycol) that have been reported to resolve or alleviate problems caused by secondary structures in the DNA. This nucleotide analog was also tested in PCR amplification of DNA regions with intermediate GC content, producing the expected amplicon in each case with a melting temperature (Tm) clearly below the Tm of the same amplicon synthesized exclusively with the canonical bases.
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Affiliation(s)
| | - Eva González-Jasso
- CICATA, Instituto Politécnico Nacional, Querétaro, Querétaro, 76090, Mexico
| | - Anaid Antaramian
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Querétaro, 76230, Mexico
| | - Reynaldo C Pless
- CICATA, Instituto Politécnico Nacional, Querétaro, Querétaro, 76090, Mexico
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16
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Hayward BE, Zhou Y, Kumari D, Usdin K. A Set of Assays for the Comprehensive Analysis of FMR1 Alleles in the Fragile X-Related Disorders. J Mol Diagn 2016; 18:762-774. [PMID: 27528259 DOI: 10.1016/j.jmoldx.2016.06.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 05/24/2016] [Accepted: 06/01/2016] [Indexed: 12/16/2022] Open
Abstract
The diagnosis and study of the fragile X-related disorders is complicated by the difficulty of amplifying the long CGG/CCG-repeat tracts that are responsible for disease pathology, the potential presence of AGG interruptions within the repeat tract that can ameliorate expansion risk, the occurrence of variable DNA methylation that modulates disease severity, and the high frequency of mosaicism for both repeat number and methylation status. These factors complicate patient risk assessment. In addition, the variability in these parameters that is seen when patient cells are grown in culture requires their frequent monitoring to ensure reproducible results in a research setting. Many existing assays have the limited ability to amplify long alleles, particularly in a mixture of different allele sizes. Others are better at this, but are too expensive for routine use in most laboratories or for newborn screening programs and use reagents that are proprietary. We describe herein a set of assays to routinely evaluate all of these important parameters in a time- and cost-effective way.
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Affiliation(s)
- Bruce E Hayward
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Yifan Zhou
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Daman Kumari
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland.
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17
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Buschmann D, Haberberger A, Kirchner B, Spornraft M, Riedmaier I, Schelling G, Pfaffl MW. Toward reliable biomarker signatures in the age of liquid biopsies - how to standardize the small RNA-Seq workflow. Nucleic Acids Res 2016; 44:5995-6018. [PMID: 27317696 PMCID: PMC5291277 DOI: 10.1093/nar/gkw545] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/03/2016] [Indexed: 12/21/2022] Open
Abstract
Small RNA-Seq has emerged as a powerful tool in transcriptomics, gene expression profiling and biomarker discovery. Sequencing cell-free nucleic acids, particularly microRNA (miRNA), from liquid biopsies additionally provides exciting possibilities for molecular diagnostics, and might help establish disease-specific biomarker signatures. The complexity of the small RNA-Seq workflow, however, bears challenges and biases that researchers need to be aware of in order to generate high-quality data. Rigorous standardization and extensive validation are required to guarantee reliability, reproducibility and comparability of research findings. Hypotheses based on flawed experimental conditions can be inconsistent and even misleading. Comparable to the well-established MIQE guidelines for qPCR experiments, this work aims at establishing guidelines for experimental design and pre-analytical sample processing, standardization of library preparation and sequencing reactions, as well as facilitating data analysis. We highlight bottlenecks in small RNA-Seq experiments, point out the importance of stringent quality control and validation, and provide a primer for differential expression analysis and biomarker discovery. Following our recommendations will encourage better sequencing practice, increase experimental transparency and lead to more reproducible small RNA-Seq results. This will ultimately enhance the validity of biomarker signatures, and allow reliable and robust clinical predictions.
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Affiliation(s)
- Dominik Buschmann
- Department of Animal Physiology and Immunology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany Institute of Human Genetics, University Hospital, Ludwig-Maximilians-University Munich, Goethestraße 29, 80336 München, Germany
| | - Anna Haberberger
- Department of Animal Physiology and Immunology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Benedikt Kirchner
- Department of Animal Physiology and Immunology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Melanie Spornraft
- Department of Animal Physiology and Immunology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Irmgard Riedmaier
- Eurofins Medigenomix Forensik GmbH, Anzinger Straße 7a, 85560 Ebersberg, Germany Department of Anesthesiology, University Hospital, Ludwig-Maximilians-University Munich, Marchioninistraße 15, 81377 München, Germany
| | - Gustav Schelling
- Department of Physiology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Michael W Pfaffl
- Department of Animal Physiology and Immunology, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Weihenstephaner Berg 3, 85354 Freising, Germany
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18
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Cleary EM, Pal S, Azam T, Moore DJ, Swingler R, Gorrie G, Stephenson L, Colville S, Chandran S, Porteous M, Warner JP. Improved PCR based methods for detecting C9orf72 hexanucleotide repeat expansions. Mol Cell Probes 2016; 30:218-224. [PMID: 27288208 PMCID: PMC4978699 DOI: 10.1016/j.mcp.2016.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 05/27/2016] [Accepted: 06/06/2016] [Indexed: 12/13/2022]
Abstract
Due to the GC-rich, repetitive nature of C9orf72 hexanucleotide repeat expansions, PCR based detection methods are challenging. Several limitations of PCR have been reported and overcoming these could help to define the pathogenic range. There is also a need to develop improved repeat-primed PCR assays which allow detection even in the presence of genomic variation around the repeat region. We have optimised PCR conditions for the C9orf72 hexanucleotide repeat expansion, using betaine as a co-solvent and specific cycling conditions, including slow ramping and a high denaturation temperature. We have developed a flanking assay, and repeat-primed PCR assays for both 3′ and 5′ ends of the repeat expansion, which when used together provide a robust strategy for detecting the presence or absence of expansions greater than ∼100 repeats, even in the presence of genomic variability at the 3′ end of the repeat. Using our assays, we have detected repeat expansions in 47/442 Scottish ALS patients. Furthermore, we recommend the combined use of these assays in a clinical diagnostic setting. Flanking PCR across C9orf72 repeat expansions up to 900 repeats has been performed. RP-PCR assays described for both 3′ and 5′ ends of the C9orf72 repeat expansion. Robust detection of expansions by RP-PCR for mosaic samples. Limitations of RP-PCR described.
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Affiliation(s)
- Elaine M Cleary
- South East Scotland Genetics Service, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom; Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom.
| | - Suvankar Pal
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Tara Azam
- South East Scotland Genetics Service, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom
| | - David J Moore
- South East Scotland Genetics Service, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom
| | - Robert Swingler
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - George Gorrie
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Laura Stephenson
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Shuna Colville
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Siddharthan Chandran
- Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom; Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Mary Porteous
- South East Scotland Genetics Service, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom; Euan Macdonald Centre for MND Research, 49 Little France Crescent, Edinburgh, EH16 4SB, United Kingdom
| | - Jon P Warner
- South East Scotland Genetics Service, Western General Hospital, Edinburgh, EH4 2XU, United Kingdom
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19
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Zimenkov DV, Kulagina EV, Antonova OV, Zhuravlev VY, Gryadunov DA. Simultaneous drug resistance detection and genotyping of Mycobacterium tuberculosis using a low-density hydrogel microarray. J Antimicrob Chemother 2016; 71:1520-31. [PMID: 26929267 DOI: 10.1093/jac/dkw015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/11/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Nucleic acid amplification tests are widely used in TB diagnostics. Priority tasks in their development consist of increasing the specificity and sensitivity of the detection of resistance to a wide spectrum of anti-TB drugs. METHODS We developed a multiplexed assay allowing the detection of 116 drug resistance-determining mutations in the rpoB, katG, inhA, ahpC, gyrA, gyrB, rrs, eis and embB genes in the Mycobacterium tuberculosis complex genome and six SNPs to identify the main lineages circulating in Russia. The assay is based on the amplification of 17 fragments of the genome using the universal primer adapter technique and heat pulses at the elongation step, followed by hybridization on a microarray. RESULTS The method was evaluated using 264 pairs of clinical samples and corresponding isolates. A significant proportion (25%) of smear-negative samples were correctly analysed by microarray analysis in addition to 96% of smear-positive samples. The sensitivity and specificity of the assay exceeded 90% for rifampicin, isoniazid, ofloxacin and second-line injection drugs. In agreement with previous studies, the specificity of ethambutol resistance was as low as 57%, while the sensitivity was 89.9%. Strong association of the Beijing lineage with a resistant phenotype was observed. Euro-American lineage strains, excluding Ural and LAM, were predominantly associated with the susceptible phenotype. CONCLUSIONS The developed test has a high sensitivity and specificity and can be directly applied to clinical samples. The combination of mutation-based drug resistance profiling and basic genotyping could be useful for clinical microbiology studies and epidemiological surveillance of the M. tuberculosis complex.
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Affiliation(s)
- Danila V Zimenkov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Elena V Kulagina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Olga V Antonova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russian Federation
| | | | - Dmitry A Gryadunov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russian Federation
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20
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Saito S, Hirose K, Tsuchida M, Wakui K, Yoshimoto K, Nishiyama Y, Shibukawa M. Rapid acquisition of high-affinity DNA aptamer motifs recognizing microbial cell surfaces using polymer-enhanced capillary transient isotachophoresis. Chem Commun (Camb) 2015; 52:461-4. [PMID: 26525483 DOI: 10.1039/c5cc07268a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We present a polymer-enhanced capillary transient isotachophoresis (PectI) selection methodology for acquisition of high-affinity (kinetically inert) DNA aptamers capable of recognizing distinct microbial cell surfaces, which requires only a single electrophoretic separation between particles (free cells and cells bound with aptamers) and molecules (unbound or dissociated DNA) in free solution.
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Affiliation(s)
- Shingo Saito
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan.
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21
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Liu EP, Wang Y, He XH, Guan JJ, Wang J, Qin ZH, Sun WP. Whole Blood PCR Amplification with Pfu DNA Polymerase and Its Application in Single-Nucleotide Polymorphism Analysis. Genet Test Mol Biomarkers 2015; 19:610-6. [PMID: 26360116 DOI: 10.1089/gtmb.2015.0018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS Point-of-care genetic analysis may require polymerase chain reaction (PCR) to be carried out on whole blood. However, human blood contains natural inhibitors of PCR such as hemoglobin, immunoglobulin G, lactoferrin, and proteases, as well as anticoagulant agents, including EDTA and heparin that can reduce whole blood PCR efficiency. Our purpose was to develop a highly specific, direct whole blood single-nucleotide polymorphism (SNP) analysis method based on allele-specific (AS) PCR that is mediated by Pfu DNA polymerase and phosphorothioate-modified AS primers. RESULTS At high Mg(2+) concentrations, Pfu DNA polymerase efficiently amplified genomic DNA in a reaction solution containing up to 14% whole blood. Among the three anticoagulants tested, Pfu DNA polymerase showed the highest activity with sodium citrate. Meanwhile, Triton X-100 and betaine inhibited Pfu DNA polymerase activity in whole blood PCR, whereas trehalose had virtually no effect. These findings provided for the development of a low-cost, simple, and fast direct whole blood genotyping method that uses Pfu DNA polymerase combined with phosphorothioate AS primers for CYP2C9*3 and VKORC1(-1639) loci. CONCLUSIONS With its high DNA amplification efficiency and tolerance of various blood conditions, Pfu DNA polymerase can be used in clinical laboratories to analyze SNPs in whole blood samples.
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Affiliation(s)
- Er-Ping Liu
- 1 Department of Pharmacy, Changzhou Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University , Changzhou, China
| | - Yan Wang
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
| | - Xiao-Hui He
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
| | - Jun-Jie Guan
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
| | - Jin Wang
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
| | - Zheng-Hong Qin
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
| | - Wan-Ping Sun
- 2 Department of Pharmacology and Laboratory of Aging and Nervous Diseases, Soochow University School of Pharmaceutical Science , Suzhou, China
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22
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Lyons JI, Kerr GR, Mueller PW. Fragile X Syndrome: Scientific Background and Screening Technologies. J Mol Diagn 2015; 17:463-71. [PMID: 26162330 DOI: 10.1016/j.jmoldx.2015.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 03/05/2015] [Accepted: 04/02/2015] [Indexed: 11/26/2022] Open
Abstract
Fragile X is the most common inherited cause of mental retardation with a prevalence of 1 in 4000 for males and 1 in 5000 to 8000 for females. The American College of Medical Genetics and Genomics has recommended diagnostic testing for fragile X in symptomatic persons, women with ovarian dysfunction, and persons with tremor/ataxia syndrome. Although medical and scientific professionals do not currently recommend screening nonsymptomatic populations, improvements in current treatment approaches and ongoing clinical trials have generated growing interest in screening for fragile X. Here, we briefly review the relevant molecular basis of fragile X and fragile X testing and compare three different molecular technologies available for fragile X screening in both males and females. These technologic approaches include destabilizing the CGG-repeat region with betaine and using chimeric CGG-targeted PCR primers, using heat pulses to destabilize C-G bonds in the PCR extension step, and using melting curve analysis to differentiate expanded CGG repeats from normals. The first two-step method performed with high sensitivity and specificity. The second method provided agarose gel images that allow identification of males with expanded CGG repeats and females with expanded CGG-repeat bands which are sometimes faint. The third melting curve analysis method would require controls in each run to correct for shifting optimal cutoff values.
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Affiliation(s)
- Justine I Lyons
- Molecular Risk Assessment Laboratory, Newborn Screening and Molecular Biology Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Gregory R Kerr
- Molecular Risk Assessment Laboratory, Newborn Screening and Molecular Biology Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Patricia W Mueller
- Molecular Risk Assessment Laboratory, Newborn Screening and Molecular Biology Branch, Centers for Disease Control and Prevention, Atlanta, Georgia.
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23
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Chevillet JR, Lee I, Briggs HA, He Y, Wang K. Issues and prospects of microRNA-based biomarkers in blood and other body fluids. Molecules 2014; 19:6080-105. [PMID: 24830712 PMCID: PMC6271291 DOI: 10.3390/molecules19056080] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/07/2014] [Accepted: 05/12/2014] [Indexed: 12/21/2022] Open
Abstract
Cell-free circulating microRNAs (miRNAs) in the blood are good diagnostic biomarker candidates for various physiopathological conditions, including cancer, neurodegeneration, diabetes and other diseases. Since their discovery in 2008 as blood biomarkers, the field has expanded rapidly with a number of important findings. Despite the initial optimistic views of their potential for clinical application, there are currently no circulating miRNA-based diagnostics in use. In this article, we review the status of circulating miRNAs, examine different analytical approaches, and address some of the challenges and opportunities.
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Affiliation(s)
| | - Inyoul Lee
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Hilary A Briggs
- Laboratory of the Biology of Addictive Diseases, Rockefeller University, New York, NY 10065, USA
| | - Yuqing He
- Institute of Medical Systems Biology, Guangdong Medical College, Dongguan, Guangdong 523808, China.
| | - Kai Wang
- Institute for Systems Biology, Seattle, WA 98109, USA.
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24
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Yang W, Li X, Sun J, Shao Z. Enhanced PCR amplification of GC-rich DNA templates by gold nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2013; 5:11520-11524. [PMID: 24206448 DOI: 10.1021/am4040448] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Gold nanoparticles (AuNPs) have been reported to facilitate double-stranded DNA dissociation and improve performance of several PCR systems. Here we investigated AuNPs' effect on GC-rich DNA amplification. We found that AuNPs could enhance PCR amplification of the GNAS1 promoter region (∼84% GC) mediated by Pfu or Taq DNA polymerase. However, under optimal concentrations of AuNPs, higher amounts of Taq were required. Furthermore, the GC-rich FMR1 (80.4% GC) gene of Homo sapiens as well as exoT (67.3% GC), exsE (71% GC) and pqqF genes (74% GC) of Pseudomonas aeruginosa were also efficiently amplified. AuNPs can become an effective additive in GC-rich PCR and facilitate analysis of challenging genomic sequence in basic and clinical research.
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Affiliation(s)
- Wenchao Yang
- School of Biomedical Engineering and ‡Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Jiao Tong University , Shanghai 200240, China
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25
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Raabe CA, Tang TH, Brosius J, Rozhdestvensky TS. Biases in small RNA deep sequencing data. Nucleic Acids Res 2013; 42:1414-26. [PMID: 24198247 PMCID: PMC3919602 DOI: 10.1093/nar/gkt1021] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
High-throughput RNA sequencing (RNA-seq) is considered a powerful tool for novel gene discovery and fine-tuned transcriptional profiling. The digital nature of RNA-seq is also believed to simplify meta-analysis and to reduce background noise associated with hybridization-based approaches. The development of multiplex sequencing enables efficient and economic parallel analysis of gene expression. In addition, RNA-seq is of particular value when low RNA expression or modest changes between samples are monitored. However, recent data uncovered severe bias in the sequencing of small non-protein coding RNA (small RNA-seq or sRNA-seq), such that the expression levels of some RNAs appeared to be artificially enhanced and others diminished or even undetectable. The use of different adapters and barcodes during ligation as well as complex RNA structures and modifications drastically influence cDNA synthesis efficacies and exemplify sources of bias in deep sequencing. In addition, variable specific RNA G/C-content is associated with unequal polymerase chain reaction amplification efficiencies. Given the central importance of RNA-seq to molecular biology and personalized medicine, we review recent findings that challenge small non-protein coding RNA-seq data and suggest approaches and precautions to overcome or minimize bias.
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Affiliation(s)
- Carsten A Raabe
- Institute of Experimental Pathology (ZMBE), University of Muenster, Von-Esmarch-Strasse 56, 48149 Muenster, Germany and Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, 13200 Penang, Malaysia
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26
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Wu W, Chen J, Fang Z, Ge C, Xiang Z, Ouyang C, Lie P, Xiao Z, Yu L, Wang L, Zeng L. A self-assembled deoxyribonucleic acid concatemer for sensitive detection of single nucleotide polymorphism. Anal Chim Acta 2013; 804:235-9. [PMID: 24267087 DOI: 10.1016/j.aca.2013.09.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 09/04/2013] [Accepted: 09/29/2013] [Indexed: 10/26/2022]
Abstract
Polymerase-free and label-free strategies for DNA detection have shown excellent sensitivity and specificity in various biological samples. Herein, we propose a method for single nucleotide polymorphism (SNP) detection by using self-assembled DNA concatemers. Capture probes, bound to magnetic beads, can joint mediator probes by T4 DNA ligase in the presence of target DNA that is complementary to the capture probe and mediator probe. The mediator probes trigger self-assembly of two auxiliary probes on magnetic beads to form DNA concatemers. Separated by a magnetic rack, the double-stranded concatemers on beads can recruit a great amount of SYBR Green I and eventually result in amplified fluorescent signals. In comparison with reported methods for SNP detection, the concatemer-based approach has significant advantages of low background, simplicity, and ultrasensitivity, making it as a convenient platform for clinical applications. As a proof of concept, BRAF(T1799A) oncogene mutation, a SNP involved in diverse human cancers, was used as a model target. The developed approach using a fluorescent intercalator can detect as low as 0.1 fM target BRAF(T1799A) DNA, which is better than those previously published methods for SNP detection. This method is robust and can be used directly to measure the BRAF(T1799A) DNA in complex human serum with excellent recovery (94-103%). It is expected that this assay principle can be directed toward other SNP genes by simply changing the mediator probe and auxiliary probes.
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Affiliation(s)
- Wei Wu
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
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27
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Buckingham KJ, McMillin MJ, Brassil MM, Shively KM, Magnaye KM, Cortes A, Weinmann AS, Lyons LA, Bamshad MJ. Multiple mutant T alleles cause haploinsufficiency of Brachyury and short tails in Manx cats. Mamm Genome 2013; 24:400-8. [PMID: 23949773 PMCID: PMC3848309 DOI: 10.1007/s00335-013-9471-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 07/02/2013] [Indexed: 10/26/2022]
Abstract
Most mammals possess a tail, humans and the Great Apes being notable exceptions. One approach to understanding the mechanisms and evolutionary forces influencing development of a tail is to identify the genetic factors that influence extreme tail length variation within a species. In mice, the Tailless locus has proven to be complex, with evidence of multiple different genes and mutations with pleiotropic effects on tail length, fertility, embryogenesis, male transmission ratio, and meiotic recombination. Five cat breeds have abnormal tail length phenotypes: the American Bobtail, the Manx, the Pixie-Bob, the Kurilian Bobtail, and the Japanese Bobtail. We sequenced the T gene in several independent lineages of Manx cats from both the US and the Isle of Man and identified three 1-bp deletions and one duplication/deletion, each predicted to cause a frameshift that leads to premature termination and truncation of the carboxy terminal end of the Brachyury protein. Ninety-five percent of Manx cats with short-tail phenotypes were heterozygous for T mutations, mutant alleles appeared to be largely lineage-specific, and a maximum LOD score of 6.21 with T was obtained at a recombination fraction (Θ) of 0.00. One mutant T allele was shared with American Bobtails and Pixie-Bobs; both breeds developed more recently in the US. The ability of mutant Brachyury protein to activate transcription of a downstream target was substantially lower than wild-type protein. Collectively, these results suggest that haploinsufficiency of Brachyury is one mechanism underlying variable tail length in domesticated cats.
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Affiliation(s)
- Kati J Buckingham
- Department of Pediatrics, University of Washington School of Medicine, 1959 NE Pacific Street, HSB RR349, Box 356320, Seattle, WA, 98195, USA,
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Abstract
Researchers face a significant problem in PCR amplification of DNA fragments with high GC contents. Analysis of these regions is of importance since many regulatory regions of different genes and their first exons are GC-rich. There are a large number of protocols for amplification of GC-rich DNA, some of which perform well but are costly. Most of the economical protocols fail to perform consistently, especially on products with >80 % GC contents and a size of >300 bp. One of these protocols requires multiple additions of DNA polymerase during thermal cycling which therefore rules out its utility if a large number of samples have to be amplified. We have established a method for simultaneous amplification of specific PCR products from a large number of human DNA samples using general laboratory reagents. These amplicons have GC contents ranging from 65-85 % and sizes up to 870 bp. The protocol uses a PCR buffer containing co-solvents including 2-mercaptoethanol and bovine serum albumin for amplification of DNA. A specific thermal cycling profile is also used which incorporates a high annealing temperature in the first 7 cycles of the reactions. The PCR products are suitable for different molecular biology applications including sequencing.
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Affiliation(s)
- Sadaf Naz
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore, Pakistan.
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29
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Burke DG, Dong L, Bhat S, Forbes-Smith M, Fu S, Pinheiro L, Jing W, Emslie KR. Digital Polymerase Chain Reaction Measured pUC19 Marker as Calibrant for HPLC Measurement of DNA Quantity. Anal Chem 2013; 85:1657-64. [DOI: 10.1021/ac302925f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | - Lianhua Dong
- National Institute of Metrology, Beijing, China, 100013
| | - Somanath Bhat
- National Measurement Institute, Lindfield, Australia 2070
| | | | - Shuang Fu
- National Measurement Institute, Lindfield, Australia 2070
| | | | - Wang Jing
- National Institute of Metrology, Beijing, China, 100013
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30
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Novel Heat Pulse Extension-PCR–Based Method for Detection of Large CTG-Repeat Expansions in Myotonic Dystrophy Type 1. J Mol Diagn 2013; 15:110-5. [DOI: 10.1016/j.jmoldx.2012.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 06/13/2012] [Accepted: 07/13/2012] [Indexed: 11/19/2022] Open
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