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Chi Y, Shi J, Xing D, Tan L. Every gene everywhere all at once: High-precision measurement of 3D chromosome architecture with single-cell Hi-C. Front Mol Biosci 2022; 9:959688. [PMID: 36275628 PMCID: PMC9583135 DOI: 10.3389/fmolb.2022.959688] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
The three-dimensional (3D) structure of chromosomes influences essential biological processes such as gene expression, genome replication, and DNA damage repair and has been implicated in many developmental and degenerative diseases. In the past two centuries, two complementary genres of technology-microscopy, such as fluorescence in situ hybridization (FISH), and biochemistry, such as chromosome conformation capture (3C or Hi-C)-have revealed general principles of chromosome folding in the cell nucleus. However, the extraordinary complexity and cell-to-cell variability of the chromosome structure necessitate new tools with genome-wide coverage and single-cell precision. In the past decade, single-cell Hi-C emerges as a new approach that builds upon yet conceptually differs from bulk Hi-C assays. Instead of measuring population-averaged statistical properties of chromosome folding, single-cell Hi-C works as a proximity-based "biochemical microscope" that measures actual 3D structures of individual genomes, revealing features hidden in bulk Hi-C such as radial organization, multi-way interactions, and chromosome intermingling. Single-cell Hi-C has been used to study highly dynamic processes such as the cell cycle, cell-type-specific chromosome architecture ("structure types"), and structure-expression interplay, deepening our understanding of DNA organization and function.
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Affiliation(s)
- Yi Chi
- Biomedical Pioneering Innovation Center, Peking University, Beijing, China,Innovation Center for Genomics, Peking University, Beijing, China
| | - Jenny Shi
- Department of Neurobiology, Stanford University, Stanford, CA, United States,Department of Chemistry, Stanford University, Stanford, CA, United States,Department of Bioengineering, Stanford University, Stanford, CA, United States
| | - Dong Xing
- Biomedical Pioneering Innovation Center, Peking University, Beijing, China,Innovation Center for Genomics, Peking University, Beijing, China,*Correspondence: Longzhi Tan, ; Dong Xing,
| | - Longzhi Tan
- Department of Neurobiology, Stanford University, Stanford, CA, United States,Department of Bioengineering, Stanford University, Stanford, CA, United States,*Correspondence: Longzhi Tan, ; Dong Xing,
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2
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Lah J, Hadži S. Conditional Cooperativity in DNA Minor-Groove Recognition by Oligopeptides. Molecules 2021; 26:molecules26175188. [PMID: 34500619 PMCID: PMC8434113 DOI: 10.3390/molecules26175188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
The recognition of specific DNA sequences in processes such as transcription is associated with a cooperative binding of proteins. Some transcription regulation mechanisms involve additional proteins that can influence the binding cooperativity by acting as corepressors or coactivators. In a conditional cooperativity mechanism, the same protein can induce binding cooperativity at one concentration and inhibit it at another. Here, we use calorimetric (ITC) and spectroscopic (UV, CD) experiments to show that such conditional cooperativity can also be achieved by the small DNA-directed oligopeptides distamycin and netropsin. Using a global thermodynamic analysis of the observed binding and (un)folding processes, we calculate the phase diagrams for this system, which show that distamycin binding cooperativity is more pronounced at lower temperatures and can be first induced and then reduced by increasing the netropsin or/and Na+ ion concentration. A molecular interpretation of this phenomenon is suggested.
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Schlick T, Portillo-Ledesma S, Myers CG, Beljak L, Chen J, Dakhel S, Darling D, Ghosh S, Hall J, Jan M, Liang E, Saju S, Vohr M, Wu C, Xu Y, Xue E. Biomolecular Modeling and Simulation: A Prospering Multidisciplinary Field. Annu Rev Biophys 2021; 50:267-301. [PMID: 33606945 PMCID: PMC8105287 DOI: 10.1146/annurev-biophys-091720-102019] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We reassess progress in the field of biomolecular modeling and simulation, following up on our perspective published in 2011. By reviewing metrics for the field's productivity and providing examples of success, we underscore the productive phase of the field, whose short-term expectations were overestimated and long-term effects underestimated. Such successes include prediction of structures and mechanisms; generation of new insights into biomolecular activity; and thriving collaborations between modeling and experimentation, including experiments driven by modeling. We also discuss the impact of field exercises and web games on the field's progress. Overall, we note tremendous success by the biomolecular modeling community in utilization of computer power; improvement in force fields; and development and application of new algorithms, notably machine learning and artificial intelligence. The combined advances are enhancing the accuracy andscope of modeling and simulation, establishing an exemplary discipline where experiment and theory or simulations are full partners.
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Affiliation(s)
- Tamar Schlick
- Department of Chemistry, New York University, New York, New York 10003, USA;
- Courant Institute of Mathematical Sciences, New York University, New York, New York 10012, USA
- New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200122, China
| | | | - Christopher G Myers
- Department of Chemistry, New York University, New York, New York 10003, USA;
| | - Lauren Beljak
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Justin Chen
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Sami Dakhel
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Daniel Darling
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Sayak Ghosh
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Joseph Hall
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Mikaeel Jan
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Emily Liang
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Sera Saju
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Mackenzie Vohr
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Chris Wu
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Yifan Xu
- College of Arts and Science, New York University, New York, New York 10003, USA
| | - Eva Xue
- College of Arts and Science, New York University, New York, New York 10003, USA
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4
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Orrù G, Scano A, Fais S, Loddo M, Carta MG, Steri GC, Santus S, Cappai R, Ferrando ML, Coghe F. Evaluation of " Caterina assay": An Alternative Tool to the Commercialized Kits Used for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Identification. Pathogens 2021; 10:325. [PMID: 33802049 PMCID: PMC7998653 DOI: 10.3390/pathogens10030325] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/17/2021] [Accepted: 03/01/2021] [Indexed: 11/16/2022] Open
Abstract
Here we describe the first molecular test developed in the early stage of the pandemic to diagnose the first cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Sardinian patients in February-March 2020, when diagnostic certified methodology had not yet been adopted by clinical microbiology laboratories. The "Caterina assay" is a SYBR®Green real-time reverse-transcription polymerase chain reaction (rRT-PCR), designed to detect the nucleocapsid phosphoprotein (N) gene that exhibits high discriminative variation RNA sequence among bat and human coronaviruses. The molecular method was applied to detect SARS-CoV-2 in nasal swabs collected from 2110 suspected cases. The study article describes the first molecular test developed in the early stage of the declared pandemic to identify the coronavirus disease 2019 (COVID-19) in Sardinian patients in February-March 2020, when a diagnostic certified methodology had not yet been adopted by clinical microbiology laboratories. The assay presented high specificity and sensitivity (with a detection limit ≥50 viral genomes/μL). No false-positives were detected, as confirmed by the comparison with two certified commercial kits. Although other validated molecular methods are currently in use, the Caterina assay still represents a valid and low-cost detection procedure that could be applied in countries with limited economic resources.
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Affiliation(s)
- Germano Orrù
- Department of Surgical Sciences, Molecular Biology Service (MBS), University of Cagliari, 09124 Cagliari, Italy; (A.S.); (S.F.); (M.L.F.)
- Dipartimento Servizi di Diagnosi e Cura, Azienda Ospedaliero-Universitaria di Cagliari (A.O.U.), University of Cagliari, 09024 Cagliari, Italy; (M.L.); (R.C.); (F.C.)
| | - Alessandra Scano
- Department of Surgical Sciences, Molecular Biology Service (MBS), University of Cagliari, 09124 Cagliari, Italy; (A.S.); (S.F.); (M.L.F.)
- Dipartimento Servizi di Diagnosi e Cura, Azienda Ospedaliero-Universitaria di Cagliari (A.O.U.), University of Cagliari, 09024 Cagliari, Italy; (M.L.); (R.C.); (F.C.)
| | - Sara Fais
- Department of Surgical Sciences, Molecular Biology Service (MBS), University of Cagliari, 09124 Cagliari, Italy; (A.S.); (S.F.); (M.L.F.)
| | - Miriam Loddo
- Dipartimento Servizi di Diagnosi e Cura, Azienda Ospedaliero-Universitaria di Cagliari (A.O.U.), University of Cagliari, 09024 Cagliari, Italy; (M.L.); (R.C.); (F.C.)
| | - Mauro Giovanni Carta
- Department of Medical Sciences and Public Health, University of Cagliari, 09124 Cagliari, Italy;
| | - Giorgio Carlo Steri
- Azienda per la Tutela della Salute (ATS), Aree Socio-Sanitarie Locali (ASSL) of Cagliari, 09131 Cagliari, Italy; (G.C.S.); (S.S.)
| | - Simonetta Santus
- Azienda per la Tutela della Salute (ATS), Aree Socio-Sanitarie Locali (ASSL) of Cagliari, 09131 Cagliari, Italy; (G.C.S.); (S.S.)
| | - Riccardo Cappai
- Dipartimento Servizi di Diagnosi e Cura, Azienda Ospedaliero-Universitaria di Cagliari (A.O.U.), University of Cagliari, 09024 Cagliari, Italy; (M.L.); (R.C.); (F.C.)
| | - Maria Laura Ferrando
- Department of Surgical Sciences, Molecular Biology Service (MBS), University of Cagliari, 09124 Cagliari, Italy; (A.S.); (S.F.); (M.L.F.)
| | - Ferdinando Coghe
- Dipartimento Servizi di Diagnosi e Cura, Azienda Ospedaliero-Universitaria di Cagliari (A.O.U.), University of Cagliari, 09024 Cagliari, Italy; (M.L.); (R.C.); (F.C.)
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5
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Hadži S, Lah J. Origin of heat capacity increment in DNA folding: The hydration effect. Biochim Biophys Acta Gen Subj 2020; 1865:129774. [PMID: 33164852 DOI: 10.1016/j.bbagen.2020.129774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/09/2020] [Accepted: 10/20/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Understanding DNA folding thermodynamics is crucial for prediction of DNA thermal stability. It is now well established that DNA folding is accompanied by a decrease of the heat capacity ∆cp, F, however its molecular origin is not understood. In analogy to protein folding it has been assumed that this is due to dehydration of DNA constituents, however no evidence exists to support this conclusion. METHODS Here we analyze partial molar heat capacity of nucleic bases and nucleosides in aqueous solutions obtained from calorimetric experiments and calculate the hydration heat capacity contribution ∆cphyd. RESULTS We present hydration heat capacity contributions of DNA constituents and show that they correlate with the solvent accessible surface area. The average contribution for nucleic base dehydration is +0.56 J mol-1 K-1 Å-2 and can be used to estimate the ∆cp, F contribution for DNA folding. CONCLUSIONS We show that dehydration is one of the major sources contributing to the observed ∆cp, F increment in DNA folding. Other possible sources contributing to the overall ∆cp, F should be significant but appear to compensate each other to high degree. The calculated ∆cphyd for duplexes and noncanonical DNA structures agree excellently with the overall experimental ∆cp, F values. By contrast, empirical parametrizations developed for proteins result in poor ∆cphyd predictions and should not be applied to DNA folding. GENERAL SIGNIFICANCE Heat capacity is one of the main thermodynamic quantities that strongly affects thermal stability of macromolecules. At the molecular level the heat capacity in DNA folding stems from removal of water from nucleobases.
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Affiliation(s)
- S Hadži
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia.
| | - J Lah
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia.
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6
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Rogers RA, Meyer MR, Stewart KM, Eyring GM, Fleming AM, Burrows CJ. Hysteresis in poly-2'-deoxycytidine i-motif folding is impacted by the method of analysis as well as loop and stem lengths. Biopolymers 2020; 112:e23389. [PMID: 33098582 DOI: 10.1002/bip.23389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/06/2020] [Accepted: 06/11/2020] [Indexed: 02/06/2023]
Abstract
In DNA, i-motif (iM) folds occur under slightly acidic conditions when sequences rich in 2'-deoxycytidine (dC) nucleotides adopt consecutive dC self base pairs. The pH stability of an iM is defined by the midpoint in the pH transition (pHT ) between the folded and unfolded states. Two different experiments to determine pHT values via circular dichroism (CD) spectroscopy were performed on poly-dC iMs of length 15, 19, or 23 nucleotides. These experiments demonstrate two points: (1) pHT values were dependent on the titration experiment performed, and (2) pH-induced denaturing or annealing processes produced isothermal hysteresis in the pHT values. These results in tandem with model iMs with judicious mutations of dC to thymidine to favor particular folds found the hysteresis was maximal for the shorter poly-dC iMs and those with an even number of base pairs, while the hysteresis was minimal for longer poly-dC iMs and those with an odd number of base pairs. Experiments to follow the iM folding via thermal changes identified thermal hysteresis between the denaturing and annealing cycles. Similar trends were found to those observed in the CD experiments. The results demonstrate that the method of iM analysis can impact the pHT parameter measured, and hysteresis was observed in the pHT and Tm values.
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Affiliation(s)
- R Aaron Rogers
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Madeline R Meyer
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Kayla M Stewart
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Gabriela M Eyring
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
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7
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Beniaminov A, Shchyolkina A, Kaluzhny D. Conformational features of intramolecular G4-DNA constrained by single-nucleotide loops. Biochimie 2019; 160:122-128. [PMID: 30840852 DOI: 10.1016/j.biochi.2019.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 02/22/2019] [Indexed: 11/28/2022]
Abstract
Conformation of the telomeric DNA fragment dG3(TTAG3)3 depends on multiple factors including solution conditions, length, and the nucleotide sequence of the flanking regions. In potassium solution, this sequence tends to adopt hybrid (3 + 1) G-quadruplex (G4) Form 1 or Form 2 conformation contingent on the flanking nucleotides. Theoretically, other (3 + 1) G4 folds (beyond Forms 1 and 2) are not sterically forbidden, but are presumably energetically disfavored. We report here on the effect of substituting the TTA loop with a single T nucleotide for one, two, or three loops of telomeric DNA that allowed us to expand the conformational diversity of the G4 DNA. Circular dichroism, gel migration, and chemical probing with DMS and ZnP1 (a porphyrin derivative sensitive to G4 conformation) were applied to monitor conformations that occurred upon shortening each loop to a single nucleotide. We found that all oligonucleotide models formed an intramolecular quadruplex structure and that shortening the loops led to the prevalence of G4 with quartets of the same polarity. Despite similar CD signatures, each modified sequence had one of three specific patterns of light-induced oxidation with ZnP1. According to the predominant modification pattern, folding of each sequence could be assigned to one of three major G4 conformations: parallel and two different (3 + 1) G4 folds. We here provide novel experimental evidence of the propensity for modified telomeric sequences to form a (3 + 1) G4 conformer containing one lateral and two propeller loops.
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Affiliation(s)
- Artemy Beniaminov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Anna Shchyolkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Dmitry Kaluzhny
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991, Moscow, Russia.
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8
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Leveille MP, Tran T, Dingillo G, Cannon B. Detection of Mg 2+-dependent, coaxial stacking rearrangements in a bulged three-way DNA junction by single-molecule FRET. Biophys Chem 2018; 245:25-33. [PMID: 30551070 DOI: 10.1016/j.bpc.2018.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 12/15/2022]
Abstract
Three-way helical junctions (3WJs) arise in genetic processing, and they have architectural and functional roles in structured nucleic acids. An internal bulge at the junction core allows the helical domains to become oriented into two possible, coaxially stacked conformers. Here, the helical stacking arrangements for a series of bulged, DNA 3WJs were examined using ensemble fluorescence resonance energy transfer (FRET) and single-molecule FRET (smFRET) approaches. The 3WJs varied according to the GC content and sequence of the junction core as well as the pyrimidine content of the internal bulge. Mg2+ titration experiments by ensemble FRET show that both stacking conformations have similar Mg2+ requirements for folding. Strikingly, smFRET experiments reveal that a specific junction sequence can populate both conformers and that this junction undergoes continual interconversion between the two stacked conformers. These findings will support the development of folding principles for the rational design of functional DNA nanostructures.
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Affiliation(s)
| | - Thao Tran
- Department of Physics, Loyola University Chicago, Chicago, IL, USA
| | - Gianna Dingillo
- Department of Physics, Loyola University Chicago, Chicago, IL, USA
| | - Brian Cannon
- Department of Physics, Loyola University Chicago, Chicago, IL, USA.
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9
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Jeong KB, Luo K, Lim MC, Jung JY, Yu JS, Kim KB, Kim YR. Reduction of DNA Folding by Ionic Liquids and Its Effects on the Analysis of DNA-Protein Interaction Using Solid-State Nanopore. Small 2018; 14:e1801375. [PMID: 29971919 DOI: 10.1002/smll.201801375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/28/2018] [Indexed: 06/08/2023]
Abstract
DNA folding is not desirable for solid-state nanopore techniques when analyzing the interaction of a biomolecule with its specific binding sites on DNA since the signal derived from the binding site could be buried by a large signal from the folding of DNA nearby. To resolve the problems associated with DNA folding, ionic liquids (ILs), which are known to interact with DNA through charge-charge and hydrophobic interactions are employed. 1-n-butyl-3-methylimidazolium chloride (C4 mim) is found to be the most effective in lowering the incident of DNA folding during its translocation through solid-state nanopores (4-5 nm diameter). The rate of folding signals from the translocation of DNA-C4 mim is decreased by half in comparison to that from the control bare DNA. The conformational changes of DNA upon complexation with C4 mim are further examined using atomic force microscopy, showing that the entanglement of DNA which is common in bare DNA is not observed when treated with C4 mim. The stretching effect of C4 mim on DNA strands improves the detection accuracy of nanopore for identifying the location of zinc finger protein bound to its specific binding site in DNA by lowering the incident of DNA folding.
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Affiliation(s)
- Ki-Baek Jeong
- Institute of Life Sciences and Resources, Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
| | - Ke Luo
- Institute of Life Sciences and Resources, Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
| | - Min-Cheol Lim
- Food Safety Research Group, Korea Food Research Institute, Sungnam, 13539, South Korea
| | - Jong-Yoon Jung
- Institute of Life Sciences and Resources, Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
| | - Jae-Seok Yu
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea
| | - Ki-Bum Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Korea
| | - Young-Rok Kim
- Institute of Life Sciences and Resources, Department of Food Science and Biotechnology, Kyung Hee University, Yongin, 17104, South Korea
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Abstract
Meta-analyses of genome-wide association studies (GWAS) have improved our understanding of the genetic foundations of a number of diseases, including diabetes. However, single nucleotide polymorphisms (SNPs) that are identified by GWAS, especially those that fall outside of gene regions, do not always clearly link to the underlying biology. Despite this, these SNPs have often been validated through re-sequencing efforts as not just tag SNPs, but as causative SNPs, and so must play a role in disease development or progression. In this study, we show how the 3D genome (spatial connections) and trans-expression Quantitative Trait Loci connect diabetes loci from different GWAS meta-analyses, informing the backbone of regulatory networks. Our findings include a three-way functional-spatial connection between the TM6SF2, CTRB1-BCAR1, and CELSR2-PSRC1 loci (rs201189528, rs7202844, and rs7202844, respectively) connected through the KCNIP3 and BCAR1/BCAR3 loci, respectively. These spatial hubs serve as an example of how loci in genes with little biological connection to disease come together to contribute to the diabetes phenotype.
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Affiliation(s)
| | - Justin M. O’Sullivan
- Liggins Institute, University of Auckland, Auckland, New Zealand
- Gravida: National Centre for Growth and Development, University of Auckland, Auckland, New Zealand
- *Correspondence: Justin M. O’Sullivan, The Liggins Institute, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand,
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Mironov GG, Okhonin V, Khan N, Clouthier CM, Berezovski MV. Conformational Dynamics of DNA G-Quadruplex in Solution Studied by Kinetic Capillary Electrophoresis Coupled On-line with Mass Spectrometry. ChemistryOpen 2014; 3:58-64. [PMID: 24808992 PMCID: PMC4000168 DOI: 10.1002/open.201400002] [Citation(s) in RCA: 10] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Indexed: 12/03/2022] Open
Abstract
G-quadruplex-forming DNA/RNA sequences play an important role in the regulation of biological functions and development of new anticancer and anti-aging drugs. In this work, we couple on-line kinetic capillary electrophoresis with mass spectrometry (KCE-MS) to study conformational dynamics of DNA G-quadruplexes in solution. We show that peaks shift and its widening in KCE can be used for measuring rate and equilibrium constants for DNA–metal affinity interactions and G-quadruplex formation; and ion mobility mass spectrometry (IM-MS) provides information about relative sizes, absolute molecular masses and stoichiometry of DNA complexes. KCE-MS separates a thrombin-binding aptamer d[GGTTGGTGTGGTTGG] from mutated sequences based on affinity to potassium, and reveals the apparent equilibrium folding constant (KF≈150 μm), folding rate constant (kon≈1.70×103 s−1 m−1), unfolding rate constant (koff≈0.25 s−1), half-life time of the G-quadruplex (t1/2≈2.8 s), and relaxation time (τ≈3.9 ms at physiological 150 mm [K+]). In addition, KCE-MS screens for a GQ-stabilizing/-destabilizing effect of DNA binding dyes and an anticancer drug, cisplatin.
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Affiliation(s)
- Gleb G Mironov
- Department of Chemistry, University of Ottawa 10 Marie Curie, Ottawa K1N 6N5 (Canada)
| | - Victor Okhonin
- Department of Chemistry, University of Ottawa 10 Marie Curie, Ottawa K1N 6N5 (Canada)
| | - Nasrin Khan
- Department of Chemistry, University of Ottawa 10 Marie Curie, Ottawa K1N 6N5 (Canada)
| | | | - Maxim V Berezovski
- Department of Chemistry, University of Ottawa 10 Marie Curie, Ottawa K1N 6N5 (Canada)
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12
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Schierding W, Cutfield WS, O'Sullivan JM. The missing story behind Genome Wide Association Studies: single nucleotide polymorphisms in gene deserts have a story to tell. Front Genet 2014; 5:39. [PMID: 24600475 PMCID: PMC3927098 DOI: 10.3389/fgene.2014.00039] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [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: 11/11/2013] [Accepted: 01/31/2014] [Indexed: 11/13/2022] Open
Abstract
Genome wide association studies are central to the evolution of personalized medicine. However, the propensity for single nucleotide polymorphisms (SNPs) to fall outside of genes means that understanding how these polymorphisms alter cellular function requires an expanded view of human genetics. Integrating the study of genome structure (chromosome conformation capture) into its function opens up new avenues of exploration. Changes in the epigenome associated with SNPs in gene deserts will allow us to define complex diseases in a much clearer manner, and usher in a new era of disease pathway exploration.
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Affiliation(s)
| | - Wayne S. Cutfield
- Liggins Institute, University of AucklandAuckland, New Zealand
- Gravida – National Centre for Growth and DevelopmentAuckland, New Zealand
| | - Justin M. O'Sullivan
- Liggins Institute, University of AucklandAuckland, New Zealand
- Gravida – National Centre for Growth and DevelopmentAuckland, New Zealand
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13
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Abstract
Before DNA replication can be initiated a definite number of adenosine triphosphate (ATP) containing pre-replication protein complexes (pre-RCs) must be assembled and bound to DNA like in a super-critical mass. A chemically driven dynamics of the Ginzburg-Landau (GL) type is derived, using the non-equilibrium equation for binding of pre-RCs to DNA and a probabilistic conformational distribution of these protein complexes. This dynamics, in which the DNA-protein system behaves like a nonlinear elastically braced string (NEBS), can control the cell cycle via conformational transitions such that G(2) cells contain exactly twice as much DNA as G(1) cells. After adjustment of previously-made derivations, the model is compared with cell growth data from the T lymphocyte MLA-144.
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Affiliation(s)
- Leif Matsson
- Department of Physics, Condensed Matter Theory Division, Göteborg University, S-412 96 Göteborg, Sweden
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