1
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León-Paz-de-Rodríguez GE, Rodríguez-León E, Iñiguez-Palomares R. DNA Hyperstructure. ACS OMEGA 2024; 9:9013-9026. [PMID: 38434827 PMCID: PMC10905968 DOI: 10.1021/acsomega.3c07379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 12/29/2023] [Accepted: 01/24/2024] [Indexed: 03/05/2024]
Abstract
This study presents a new procedure to condense DNA molecules and precipitate them onto a glass slide. The resulting DNA molecules undergo autonomous self-assembly, creating closed superstructures on the micrometer scale, which are called DNA hyperstructures. These structures can be observed using low-magnification (4×) light microscopy. Precisely controlling the alcohol/glacial acetic acid ratio and DNA concentration during precipitation enabled the regulation of structure compaction on the slide. The alcohol/glacial acetic acid ratio is inversely proportional to the DNA concentration to achieve optimal compaction on the slide. Confocal microscopy fluorescence analysis of DNA extracts stained with DAPI shows that nucleic acids self-assemble to form structures during precipitation on the slide. This methodology is relevant since it facilitates the precipitation and visualization of DNA, regardless of its origin or molecular weight. To confirm its versatility, results with DNA extracted from human peripheral blood, the Lambda virus, and plasmid pBR322 are presented. The study examined the morphological features of DNA hyperstructures in both healthy individuals and those diagnosed with different medical conditions or illnesses, revealing distinct patterns specific to each case. This innovative technology has potential for disease detection in peripheral blood samples, ranging from cancer and Alzheimer's disease to determining the gender of the gestational product at an early stage.
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2
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Bauer J, Reichl A, Tinnefeld P. Kinetic Referencing Allows Identification of Epigenetic Cytosine Modifications by Single-Molecule Hybridization Kinetics and Superresolution DNA-PAINT Microscopy. ACS NANO 2024; 18:1496-1503. [PMID: 38157484 DOI: 10.1021/acsnano.3c08451] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
We develop a DNA origami-based internal kinetic referencing system with a colocalized reference and target molecule to provide increased sensitivity and robustness for transient binding kinetics. To showcase this, we investigate the subtle changes in binding strength of DNA oligonucleotide hybrids induced by cytosine modifications. These cytosine modifications, especially 5-methylcytosine but also its oxidized derivatives, have been increasingly studied in the context of epigenetics. Recently revealed correlations of epigenetic modifications and disease also render them interesting biomarkers for early diagnosis. Internal kinetic referencing allows us to probe and compare the influence of the different epigenetic cytosine modifications on the strengths of 7-nucleotide long DNA hybrids with one or two modified nucleotides by single-molecule imaging of their transient binding, revealing subtle differences in binding times. Interestingly, the influence of epigenetic modifications depends on their position in the DNA strand, and in the case of two modifications, effects are additive. The sensitivity of the assay indicates its potential for the direct detection of epigenetic disease markers.
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Affiliation(s)
- Julian Bauer
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
| | - Andreas Reichl
- Department of Chemistry, Ludwig-Maximilians-Universität München, Würmtalstraße 201, 81377 München, Germany
| | - Philip Tinnefeld
- Department of Chemistry and Center for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany
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3
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Zeng Y, Mao Y, Chen Y, Wang Y, Xu S. DNA methylation induces subtle mechanical alteration but significant chiral selectivity. Chem Commun (Camb) 2023; 59:14855-14858. [PMID: 38015496 PMCID: PMC10794036 DOI: 10.1039/d3cc05211g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
DNA methylation is a major epigenetic modification that is closely related to human health. Many experimental techniques as well as theoretical methods have been used to detect the modified nucleotides and identify their effects on molecular binding. It remains challenging to resolve the effect of few methylations of nucleic acids. Using super-resolution force spectroscopy, we firstly revealed that single cytosine methylation increases the mechanical stability of the DNA duplex by 1.9 ± 0.3 pN. Methylation also induces significant chiral selectivity towards drug molecules such as d,l-tetrahydropalmatine. Our results precisely quantify the mechanical effect of methylation and suggest that drug design should take methylation into consideration for enhanced selectivity.
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Affiliation(s)
- Yi Zeng
- Department of Chemistry, University of Houston, Houston, TX 77204, USA.
| | - Yujia Mao
- Department of Chemistry, University of Houston, Houston, TX 77204, USA.
| | - Yanjun Chen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA.
| | - Yuhong Wang
- Department of Biology and Biochemistry, University of Houston, TX 77204, USA.
| | - Shoujun Xu
- Department of Chemistry, University of Houston, Houston, TX 77204, USA.
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4
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Biswas A, Basu A. The impact of the sequence-dependent physical properties of DNA on chromatin dynamics. Curr Opin Struct Biol 2023; 83:102698. [PMID: 37696706 DOI: 10.1016/j.sbi.2023.102698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/07/2023] [Accepted: 08/14/2023] [Indexed: 09/13/2023]
Abstract
The local mechanical properties of DNA depend on local sequence. Here we review recent genomic, structural, and computational efforts at deciphering the "mechanical code", i.e., the mapping between sequence and mechanics. We then discuss works that suggest how evolution has exploited the mechanical code to control the energetics of DNA-deforming biological processes such as nucleosome organization, transcription factor binding, DNA supercoiling, gene regulation, and 3D chromatin organization. As a whole, these recent works suggest that DNA sequence in diverse organisms can encode regulatory information governing diverse processes via the mechanical code.
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Affiliation(s)
- Aditi Biswas
- Department of Biosciences, Durham University, Durham, UK
| | - Aakash Basu
- Department of Biosciences, Durham University, Durham, UK.
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5
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Avraham S, Schütz L, Käver L, Dankers A, Margalit S, Michaeli Y, Zirkin S, Torchinsky D, Gilat N, Bahr O, Nifker G, Koren-Michowitz M, Weinhold E, Ebenstein Y. Chemo-Enzymatic Fluorescence Labeling Of Genomic DNA For Simultaneous Detection Of Global 5-Methylcytosine And 5-Hydroxymethylcytosine. Chembiochem 2023; 24:e202300400. [PMID: 37518671 DOI: 10.1002/cbic.202300400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/05/2023] [Accepted: 07/27/2023] [Indexed: 08/01/2023]
Abstract
5-Methylcytosine and 5-hydroxymethylcytosine are epigenetic modifications involved in gene regulation and cancer. We present a new, simple, and high-throughput platform for multi-color epigenetic analysis. The novelty of our approach is the ability to multiplex methylation and de-methylation signals in the same assay. We utilize an engineered methyltransferase enzyme that recognizes and labels all unmodified CpG sites with a fluorescent cofactor. In combination with the already established labeling of the de-methylation mark 5-hydroxymethylcytosine via enzymatic glycosylation, we obtained a robust platform for simultaneous epigenetic analysis of these marks. We assessed the global epigenetic levels in multiple samples of colorectal cancer and observed a 3.5-fold reduction in 5hmC levels but no change in DNA methylation levels between sick and healthy individuals. We also measured epigenetic modifications in chronic lymphocytic leukemia and observed a decrease in both modification levels (5-hydroxymethylcytosine: whole blood 30 %; peripheral blood mononuclear cells (PBMCs) 40 %. 5-methylcytosine: whole blood 53 %; PBMCs 48 %). Our findings propose using a simple blood test as a viable method for analysis, simplifying sample handling in diagnostics. Importantly, our results highlight the assay's potential for epigenetic evaluation of clinical samples, benefiting research and patient management.
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Affiliation(s)
- Sigal Avraham
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Leonie Schütz
- Institute of Organic Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Larissa Käver
- Institute of Organic Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Andreas Dankers
- Institute of Organic Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Sapir Margalit
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
| | - Yael Michaeli
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Shahar Zirkin
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Dmitry Torchinsky
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Noa Gilat
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Omer Bahr
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Gil Nifker
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
| | | | - Elmar Weinhold
- Institute of Organic Chemistry, RWTH Aachen University, 52056, Aachen, Germany
| | - Yuval Ebenstein
- Department of Chemistry, Raymond and Beverly SacklerFaculty of Exact Sciences, Department of Biomedical Engineering, Tel Aviv University Tel Aviv-Yafo, 6997801, Tel Aviv, Israel
- School of Chemistry,Ramat Aviv, Tel Aviv University, Tel Aviv, 6997801, Israel
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6
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Sanchez R, Mackenzie SA. On the thermodynamics of DNA methylation process. Sci Rep 2023; 13:8914. [PMID: 37264042 DOI: 10.1038/s41598-023-35166-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 05/13/2023] [Indexed: 06/03/2023] Open
Abstract
DNA methylation is an epigenetic mechanism that plays important roles in various biological processes including transcriptional and post-transcriptional regulation, genomic imprinting, aging, and stress response to environmental changes and disease. Consistent with thermodynamic principles acting within living systems and the application of maximum entropy principle, we propose a theoretical framework to understand and decode the DNA methylation process. A central tenet of this argument is that the probability density function of DNA methylation information-divergence summarizes the statistical biophysics underlying spontaneous methylation background and implicitly bears on the channel capacity of molecular machines conforming to Shannon's capacity theorem. On this theoretical basis, contributions from the molecular machine (enzyme) logical operations to Gibb entropy (S) and Helmholtz free energy (F) are intrinsic. Application to the estimations of S on datasets from Arabidopsis thaliana suggests that, as a thermodynamic state variable, individual methylome entropy is completely determined by the current state of the system, which in biological terms translates to a correspondence between estimated entropy values and observable phenotypic state. In patients with different types of cancer, results suggest that a significant information loss occurs in the transition from differentiated (healthy) tissues to cancer cells. This type of analysis may have important implications for early-stage diagnostics. The analysis of entropy fluctuations on experimental datasets revealed existence of restrictions on the magnitude of genome-wide methylation changes originating by organismal response to environmental changes. Only dysfunctional stages observed in the Arabidopsis mutant met1 and in cancer cells do not conform to these rules.
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Affiliation(s)
- Robersy Sanchez
- Department of Biology, The Pennsylvania State University, 361 Frear North Bldg, University Park, PA, 16802, USA.
| | - Sally A Mackenzie
- Departments of Biology and Plant Science, The Pennsylvania State University, 362 Frear North Bldg, University Park, PA, 16802, USA.
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7
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Shi D, Huang Y, Bai C. Studies of the Mechanism of Nucleosome Dynamics: A Review on Multifactorial Regulation from Computational and Experimental Cases. Polymers (Basel) 2023; 15:polym15071763. [PMID: 37050377 PMCID: PMC10096840 DOI: 10.3390/polym15071763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
The nucleosome, which organizes the long coil of genomic DNA in a highly condensed, polymeric way, is thought to be the basic unit of chromosomal structure. As the most important protein–DNA complex, its structural and dynamic features have been successively revealed in recent years. However, its regulatory mechanism, which is modulated by multiple factors, still requires systemic discussion. This study summarizes the regulatory factors of the nucleosome’s dynamic features from the perspective of histone modification, DNA methylation, and the nucleosome-interacting factors (transcription factors and nucleosome-remodeling proteins and cations) and focuses on the research exploring the molecular mechanism through both computational and experimental approaches. The regulatory factors that affect the dynamic features of nucleosomes are also discussed in detail, such as unwrapping, wrapping, sliding, and stacking. Due to the complexity of the high-order topological structures of nucleosomes and the comprehensive effects of regulatory factors, the research on the functional modulation mechanism of nucleosomes has encountered great challenges. The integration of computational and experimental approaches, the construction of physical modes for nucleosomes, and the application of deep learning techniques will provide promising opportunities for further exploration.
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Affiliation(s)
- Danfeng Shi
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong (Shenzhen), Shenzhen 518172, China
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Yuxin Huang
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong (Shenzhen), Shenzhen 518172, China
| | - Chen Bai
- Warshel Institute for Computational Biology, School of Life and Health Sciences, School of Medicine, The Chinese University of Hong Kong (Shenzhen), Shenzhen 518172, China
- Chenzhu (MoMeD) Biotechnology Co., Ltd., Hangzhou 310005, China
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8
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Hafner A, Mackenzie S. Re-analysis of publicly available methylomes using signal detection yields new information. Sci Rep 2023; 13:3307. [PMID: 36849495 PMCID: PMC9971211 DOI: 10.1038/s41598-023-30422-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/22/2023] [Indexed: 03/01/2023] Open
Abstract
Cytosine methylation is an epigenetic mark that participates in regulation of gene expression and chromatin stability in plants. Advancements in whole genome sequencing technologies have enabled investigation of methylome dynamics under different conditions. However, the computational methods for analyzing bisulfite sequence data have not been unified. Contention remains in the correlation of differentially methylated positions with the investigated treatment and exclusion of noise, inherent to these stochastic datasets. The prevalent approaches apply Fisher's exact test, logistic, or beta regression, followed by an arbitrary cut-off for differences in methylation levels. A different strategy, the MethylIT pipeline, utilizes signal detection to determine cut-off based on a fitted generalized gamma probability distribution of methylation divergence. Re-analysis of publicly available BS-seq data from two epigenetic studies in Arabidopsis and applying MethylIT revealed additional, previously unreported results. Methylome repatterning in response to phosphate starvation was confirmed to be tissue-specific and included phosphate assimilation genes in addition to sulfate metabolism genes not implicated in the original study. During seed germination plants undergo major methylome reprogramming and use of MethylIT allowed us to identify stage-specific gene networks. We surmise from these comparative studies that robust methylome experiments must account for data stochasticity to achieve meaningful functional analyses.
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Affiliation(s)
- Alenka Hafner
- grid.29857.310000 0001 2097 4281Department of Biology, The Pennsylvania State University, 362 Frear N Bldg, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA USA
| | - Sally Mackenzie
- Department of Biology, The Pennsylvania State University, 362 Frear N Bldg, University Park, PA, 16802, USA. .,Department of Plant Science, The Pennsylvania State University, University Park, PA, USA.
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9
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Zhao XC, Dong HL, Li XL, Yang HY, Chen XF, Dai L, Wu WQ, Tan ZJ, Zhang XH. 5-Methyl-cytosine stabilizes DNA but hinders DNA hybridization revealed by magnetic tweezers and simulations. Nucleic Acids Res 2022; 50:12344-12354. [PMID: 36477372 PMCID: PMC9757033 DOI: 10.1093/nar/gkac1122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022] Open
Abstract
5-Methyl-cytosine (5mC) is one of the most important DNA modifications and plays versatile biological roles. It is well known that 5mC stabilizes DNA duplexes. However, it remains unclear how 5mC affects the kinetics of DNA melting and hybridization. Here, we studied the kinetics of unzipping and rezipping using a 502-bp DNA hairpin by single-molecule magnetic tweezers. Under constant loading rates, 5mC increases the unzipping force but counterintuitively decreases the rezipping force at various salt and temperature conditions. Under constant forces, the non-methylated DNA hops between metastable states during unzipping and rezipping, which implies low energy barriers. Surprisingly, the 5mC DNA can't rezip after fully unzipping unless much lower forces are applied, where it rezips stochastically in a one-step manner, which implies 5mC kinetically hinders DNA hybridization and high energy barriers in DNA hybridization. All-atom molecular dynamics simulations reveal that the 5mC kinetically hinders DNA hybridization due to steric effects rather than electrostatic effects caused by the additional methyl groups of cytosines. Considering the possible high speed of DNA unzipping and zipping during replication and transcription, our findings provide new insights into the biological roles of 5mC.
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Affiliation(s)
| | | | - Xiao-Lu Li
- The Institute for Advanced Studies, College of Life Sciences, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Hong-Yu Yang
- The Institute for Advanced Studies, College of Life Sciences, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Xue-Feng Chen
- The Institute for Advanced Studies, College of Life Sciences, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
| | - Liang Dai
- Department of Physics, City University of Hong Kong, Hong Kong 999077, China
| | - Wen-Qiang Wu
- School of Life Sciences, State Key Laboratory of Crop Stress Adaptation and Improvement, Key Laboratory of Plant Stress Biology, Henan University, Kaifeng 475001, China
| | - Zhi-Jie Tan
- Correspondence may also be addressed to Zhi-Jie Tan. Tel: +86 15827627809; Fax: +86 02768752569;
| | - Xing-Hua Zhang
- To whom correspondence should be addressed. Tel: +86 15827632615; Fax: +86 02768753780;
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10
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Basu A, Bobrovnikov DG, Cieza B, Arcon JP, Qureshi Z, Orozco M, Ha T. Deciphering the mechanical code of the genome and epigenome. Nat Struct Mol Biol 2022; 29:1178-1187. [PMID: 36471057 PMCID: PMC10142808 DOI: 10.1038/s41594-022-00877-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 10/18/2022] [Indexed: 12/12/2022]
Abstract
Diverse DNA-deforming processes are impacted by the local mechanical and structural properties of DNA, which in turn depend on local sequence and epigenetic modifications. Deciphering this mechanical code (that is, this dependence) has been challenging due to the lack of high-throughput experimental methods. Here we present a comprehensive characterization of the mechanical code. Utilizing high-throughput measurements of DNA bendability via loop-seq, we quantitatively established how the occurrence and spatial distribution of dinucleotides, tetranucleotides and methylated CpG impact DNA bendability. We used our measurements to develop a physical model for the sequence and methylation dependence of DNA bendability. We validated the model by performing loop-seq on mouse genomic sequences around transcription start sites and CTCF-binding sites. We applied our model to test the predictions of all-atom molecular dynamics simulations and to demonstrate that sequence and epigenetic modifications can mechanically encode regulatory information in diverse contexts.
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Affiliation(s)
- Aakash Basu
- Department of Biosciences, Durham University, Durham, UK. .,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Dmitriy G Bobrovnikov
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Basilio Cieza
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Juan Pablo Arcon
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Zan Qureshi
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Biochemistry and Biomedicine, Universitat de Barcelona, Barcelona, Spain
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA. .,Howard Hughes Medical Institute, Baltimore, MD, USA.
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11
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Yeou S, Hwang J, Yi J, Kim C, Kim SK, Lee NK. Cytosine methylation regulates DNA bendability depending on the curvature. Chem Sci 2022; 13:7516-7525. [PMID: 35872822 PMCID: PMC9242020 DOI: 10.1039/d1sc07115g] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/01/2022] [Indexed: 11/21/2022] Open
Abstract
Cytosine methylation plays an essential role in many biological processes, such as nucleosome inactivation and regulation of gene expression. The modulation of DNA mechanics may be one of the regulatory mechanisms influenced by cytosine methylation. However, it remains unclear how methylation influences DNA mechanics. Here, we show that methylation has contrasting effects on the bending property of dsDNA depending on DNA curvature. We directly applied bending force on 30 base pairs of dsDNA using a D-shaped DNA nanostructure and measured the degree of bending using single-molecule fluorescence resonance energy transfer without surface immobilization. When dsDNA is weakly bent, methylation increases the stiffness of dsDNA. The stiffness of dsDNA increased by approximately 8% with a single methylation site for 30 bp dsDNA. When dsDNA is highly bent by a strong force, it forms a kink, i.e., a sharp bending of dsDNA. Under strong bending, methylation destabilizes the non-kink form compared with the kink form, which makes dsDNA near the kink region apparently more bendable. However, if the kink region is methylated, the kink form is destabilized, and dsDNA becomes stiffer. As a result, methylation increases the stiffness of weakly bent dsDNA and concurrently can promote kink formation, which may stabilize the nucleosome structure. Our results provide new insight into the effect of methylation, showing that cytosine methylation has opposite effects on DNA mechanics depending on its curvature and methylation location.
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Affiliation(s)
- Sanghun Yeou
- Department of Chemistry, Seoul National University 08832 Seoul Republic of Korea
| | - Jihee Hwang
- Department of Chemistry, Seoul National University 08832 Seoul Republic of Korea
| | - Jaehun Yi
- Department of Chemistry, Seoul National University 08832 Seoul Republic of Korea
| | - Cheolhee Kim
- National Science Museum Daejeon 34143 Republic of Korea
| | - Seong Keun Kim
- Department of Chemistry, Seoul National University 08832 Seoul Republic of Korea
| | - Nam Ki Lee
- Department of Chemistry, Seoul National University 08832 Seoul Republic of Korea
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12
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Andrade UMS, Castro ASB, Oliveira PHF, da Silva LHM, Rocha MS. Imidazolium-based ionic liquids binding to DNA: Mechanical effects and thermodynamics of the interactions. Int J Biol Macromol 2022; 214:500-511. [PMID: 35714872 DOI: 10.1016/j.ijbiomac.2022.06.069] [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: 05/04/2022] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022]
Abstract
We performed a robust characterization of the molecular interactions between the DNA molecule and two imidazolium-based ionic liquids (ILs): 1-Butyl-3-methylimidazolium chloride ([bmim]Cl) and 1-Octyl-3-methylimidazolium chloride ([omim]Cl), using single molecule approaches (optical and magnetic tweezers) and bulk techniques (isothermal titration calorimetry and conductivity measurements). Optical and magnetic tweezers allowed us to obtain the changes on the mechanical properties of the DNA complexes formed with both ILs, as well as the relevant physicochemical (binding) parameters of the interaction. Despite the weak binding measured between DNA and the two ILs, we identify a transition on the regime of polymer elasticity of the complexes formed, which results in a relevant DNA compaction for high IL concentrations. In addition, isothermal titration calorimetry and conductivity complemented the single molecule investigation, giving a complete thermodynamic characterization of the interactions and allowing the identification of the most relevant driving forces at various different concentration ranges of the ILs. Based on the results obtained with all the employed techniques, we propose a model for the binding schemes involving DNA and both [bmim]Cl and [omim]Cl.
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Affiliation(s)
- U M S Andrade
- Departamento de Física, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil; Departamento de Formação Geral, Centro Federal de Educação Tecnológica de Minas Gerais, Curvelo, Minas Gerais, Brazil.
| | - A S B Castro
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - P H F Oliveira
- Departamento de Física, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - L H M da Silva
- Departamento de Química, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - M S Rocha
- Departamento de Física, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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13
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Mechanistic Study on DNA Mutation of the Cytosine Methylation Reaction at C5 Position. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.103956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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14
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The Dynamic Regulation of G-Quadruplex DNA Structures by Cytosine Methylation. Int J Mol Sci 2022; 23:ijms23052407. [PMID: 35269551 PMCID: PMC8910436 DOI: 10.3390/ijms23052407] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/01/2023] Open
Abstract
It is well known that certain non B-DNA structures, including G-quadruplexes, are key elements that can regulate gene expression. Here, we explore the theory that DNA modifications, such as methylation of cytosine, could act as a dynamic switch by promoting or alleviating the structural formation of G-quadruplex structures in DNA or RNA. The interaction between epigenetic DNA modifications, G4 formation, and the 3D architecture of the genome is a complex and developing area of research. Although there is growing evidence for such interactions, a great deal still remains to be discovered. In vivo, the potential effect that cytosine methylation may have on the formation of DNA structures has remained largely unresearched, despite this being a potential mechanism through which epigenetic factors could regulate gene activity. Such interactions could represent novel mechanisms for important biological functions, including altering nucleosome positioning or regulation of gene expression. Furthermore, promotion of strand-specific G-quadruplex formation in differentially methylated genes could have a dynamic role in directing X-inactivation or the control of imprinting, and would be a worthwhile focus for future research.
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15
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Li S, Peng Y, Landsman D, Panchenko AR. DNA methylation cues in nucleosome geometry, stability and unwrapping. Nucleic Acids Res 2022; 50:1864-1874. [PMID: 35166834 DOI: 10.1093/nar/gkac097] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 01/29/2022] [Accepted: 02/01/2022] [Indexed: 01/04/2023] Open
Abstract
Cytosine methylation at the 5-carbon position is an essential DNA epigenetic mark in many eukaryotic organisms. Although countless structural and functional studies of cytosine methylation have been reported, our understanding of how it influences the nucleosome assembly, structure, and dynamics remains obscure. Here, we investigate the effects of cytosine methylation at CpG sites on nucleosome dynamics and stability. By applying long molecular dynamics simulations on several microsecond time scale, we generate extensive atomistic conformational ensembles of full nucleosomes. Our results reveal that methylation induces pronounced changes in geometry for both linker and nucleosomal DNA, leading to a more curved, under-twisted DNA, narrowing the adjacent minor grooves, and shifting the population equilibrium of sugar-phosphate backbone geometry. These DNA conformational changes are associated with a considerable enhancement of interactions between methylated DNA and the histone octamer, doubling the number of contacts at some key arginines. H2A and H3 tails play important roles in these interactions, especially for DNA methylated nucleosomes. This, in turn, prevents a spontaneous DNA unwrapping of 3-4 helical turns for the methylated nucleosome with truncated histone tails, otherwise observed in the unmethylated system on several microseconds time scale.
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Affiliation(s)
- Shuxiang Li
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada
| | - Yunhui Peng
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - David Landsman
- National Center for Biotechnology Information, National Institutes of Health, Bethesda, MD, USA
| | - Anna R Panchenko
- Department of Pathology and Molecular Medicine, School of Medicine, Queen's University, ON, Canada
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16
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Shim WC, Woo S, Park JW. Nanoscale Force-Mapping-Based Quantification of Low-Abundance Methylated DNA. NANO LETTERS 2022; 22:1324-1330. [PMID: 35080393 DOI: 10.1021/acs.nanolett.1c04637] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Methylation changes at cytosine-guanine dinucleotide (CpG) sites in genes are closely related to cancer development. Thus, detection and quantification of low-abundance methylated DNA is critical for early diagnosis. Here, we report an atomic force microscopy (AFM)-based quantification method for DNA that contains methyl-CpG at a specific site, without any treatment to the target DNA such as chemical labeling, fluorescence tagging, or amplification. We employed AFM-tip-tethered methyl-CpG-binding proteins to probe surface-captured methylated DNA. We observed a linear correlation (R2 = 0.982) between the input copy number and detected copy number, in the low copy number regime (10 or fewer; subattomolar concentrations). For a mixture of methylated and nonmethylated DNA that resembles clinical samples, we were still able to quantify the methylated DNA. These results highlight the potential of our force-mapping-based quantification method for wide applications in early detection of diseases associated with methylated DNA.
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Affiliation(s)
- Woo Cheol Shim
- Department of Chemistry, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
| | - Sungwook Woo
- Department of Chemistry, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
| | - Joon Won Park
- Department of Chemistry, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, Republic of Korea
- Institute of Convergence Science, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
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17
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Tellgren-Roth C, Couturier M. Detecting DNA Methylations in the Hyperthermoacidophilic Crenarchaeon Sulfolobus acidocaldarius Using SMRT Sequencing. Methods Mol Biol 2022; 2516:39-50. [PMID: 35922620 DOI: 10.1007/978-1-0716-2413-5_3] [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: 06/15/2023]
Abstract
DNA methylations are one of the most well-known epigenetic modifications along with histone modifications and noncoding RNAs. They are found at specific sites along the DNA in all domains of life, with 5-mC and 6-mA/4-mC being well-characterized in eukaryotes and bacteria respectively, and they have not only been described as contributing to the structure of the double helix itself but also as regulators of DNA-based processes such as replication, transcription, and recombination. Different methods have been developed to accurately identify and/or map methylated motifs to decipher the involvement of DNA methylations in regulatory networks that affect the cellular state.Although DNA methylations have been detected along archaeal genomes, their involvement as regulators of DNA-based processes remains the least known. To highlight the importance of DNA methylations in the control of key cellular mechanisms and their dynamics in archaea cells, we have used single-molecule real-time (SMRT) sequencing. This sequencing technology allows the identification and direct mapping of the methylated motifs along the genome of an organism. In this chapter, we present a step-by-step protocol for detecting DNA methylations in the hyperthermophilic crenarchaeon Sulfolobus acidocaldarius using SMRT sequencing. This protocol can easily be adapted to other prokaryotes.
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Affiliation(s)
- Christian Tellgren-Roth
- Department of Immunology, Genetics and Pathology, National Genomics Infrastructure, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Mohea Couturier
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium.
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18
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Li K, Carroll M, Vafabakhsh R, Wang XA, Wang JP. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3142-3154. [PMID: 35288750 PMCID: PMC8989542 DOI: 10.1093/nar/gkac162] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/16/2022] [Accepted: 02/23/2022] [Indexed: 11/16/2022] Open
Abstract
DNA mechanical properties play a critical role in every aspect of DNA-dependent biological processes. Recently a high throughput assay named loop-seq has been developed to quantify the intrinsic bendability of a massive number of DNA fragments simultaneously. Using the loop-seq data, we develop a software tool, DNAcycP, based on a deep-learning approach for intrinsic DNA cyclizability prediction. We demonstrate DNAcycP predicts intrinsic DNA cyclizability with high fidelity compared to the experimental data. Using an independent dataset from in vitro selection for enrichment of loopable sequences, we further verified the predicted cyclizability score, termed C-score, can well distinguish DNA fragments with different loopability. We applied DNAcycP to multiple species and compared the C-scores with available high-resolution chemical nucleosome maps. Our analyses showed that both yeast and mouse genomes share a conserved feature of high DNA bendability spanning nucleosome dyads. Additionally, we extended our analysis to transcription factor binding sites and surprisingly found that the cyclizability is substantially elevated at CTCF binding sites in the mouse genome. We further demonstrate this distinct mechanical property is conserved across mammalian species and is inherent to CTCF binding DNA motif.
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Affiliation(s)
- Keren Li
- Department of Statistics, Northwestern University, 633 Clark Street, Evanston, IL 60208, USA
- NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, IL 60208, USA
| | - Matthew Carroll
- Weinberg College IT Solutions (WITS), Northwestern University, 633 Clark Street, Evanston, IL 60208, USA
| | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Xiaozhong A Wang
- Correspondence may also be addressed to Xiaozhong A. Wang. Tel: +1 847 467 4897;
| | - Ji-Ping Wang
- To whom correspondence should be addressed. Tel: +1 847 467 6896;
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19
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Zacarias O, Petrovic AG, Abzalimov R, Pradhan P, Champeil E. Synthesis of Oligonucleotides Containing Trans Mitomycin C DNA Adducts at N 6 of Adenine and N 2 of Guanine. Chemistry 2021; 27:14263-14272. [PMID: 34319608 PMCID: PMC8516704 DOI: 10.1002/chem.202102338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Indexed: 11/09/2022]
Abstract
Mitomycin C, (MC), an antitumor drug, is a DNA alkylating agent currently used in the clinics. Inert in its native form, MC is reduced to reactive mitosenes, which undergo nucleophilic attack by guanine or adenine bases in DNA to form monoadducts as well as interstrand crosslinks (ICLs). Although ICLs are considered the most cytotoxic lesions, the role of each individual adduct in the drug's cytotoxicity is still not fully understood. Synthetic routes have been developed to access modified oligonucleotides containing dG MC-monoadducts and dG-MC-dG ICL at a single position of their base sequences to investigate the biological effects of these adducts. However, until now, oligonucleotides containing monoadducts formed by MC at the adenine base had not been available, thus preventing the examination of the role played by these lesions in the toxicity of MC. Here, we present a route to access these substrates. Structural proof of the adducted oligonucleotides were provided by enzymatic digestion to nucleosides and high-resolution mass spectral analysis. Additionally, parent oligonucleotides containing a dG monoadduct and a dG-MC-dG ICL were also produced. The stability and physical properties of all substrates were compared via CD spectroscopy and UV melting temperature studies. Finally, virtual models were created to explore the conformational space and structural features of these MC-DNA complexes.
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Affiliation(s)
- Owen Zacarias
- Science Department, John Jay College of Criminal Justice, 524 West 59th street, New York, NY, 10019, USA
| | - Ana G Petrovic
- New York Institute of Technology, 1855 Broadway, EGGC 405 A, New York, NY, 10023, USA
| | - Rinat Abzalimov
- City University of New York, Advanced Research Center, 85 St Nicholas Terrace, New York, NY, 10031, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
| | - Padmanava Pradhan
- The City College, 138th Street at Convent Avenue, New York, New York, 10031, USA
| | - Elise Champeil
- Science Department, John Jay College of Criminal Justice, 524 West 59th street, New York, NY, 10019, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
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20
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Ailloud F, Estibariz I, Suerbaum S. Evolved to vary: genome and epigenome variation in the human pathogen Helicobacter pylori. FEMS Microbiol Rev 2021; 45:5900976. [PMID: 32880636 DOI: 10.1093/femsre/fuaa042] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/31/2020] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori is a Gram-negative, spiral shaped bacterium that selectively and chronically infects the gastric mucosa of humans. The clinical course of this infection can range from lifelong asymptomatic infection to severe disease, including peptic ulcers or gastric cancer. The high mutation rate and natural competence typical of this species are responsible for massive inter-strain genetic variation exceeding that observed in all other bacterial human pathogens. The adaptive value of such a plastic genome is thought to derive from a rapid exploration of the fitness landscape resulting in fast adaptation to the changing conditions of the gastric environment. Nevertheless, diversity is also lost through recurrent bottlenecks and H. pylori's lifestyle is thus a perpetual race to maintain an appropriate pool of standing genetic variation able to withstand selection events. Another aspect of H. pylori's diversity is a large and variable repertoire of restriction-modification systems. While not yet completely understood, methylome evolution could generate enough transcriptomic variation to provide another intricate layer of adaptive potential. This review provides an up to date synopsis of this rapidly emerging area of H. pylori research that has been enabled by the ever-increasing throughput of Omics technologies and a multitude of other technological advances.
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Affiliation(s)
- Florent Ailloud
- Max von Pettenkofer Institute, Faculty of Medicine, LMU München, Pettenkoferstr. 9a, 80336 München, Germany
| | - Iratxe Estibariz
- Max von Pettenkofer Institute, Faculty of Medicine, LMU München, Pettenkoferstr. 9a, 80336 München, Germany
| | - Sebastian Suerbaum
- Max von Pettenkofer Institute, Faculty of Medicine, LMU München, Pettenkoferstr. 9a, 80336 München, Germany.,DZIF Deutsches Zentrum für Infektionsforschung, Partner Site Munich, Pettenkoferstr. 9a, 80336 München, Germany.,National Reference Center for Helicobacter pylori, Pettenkoferstr. 9a, 80336 München, Germany
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21
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Kagra D, Mahmi AS, Kumar NVS, Prabhakar PS, Sharma P. Influence of the Number, Nature and Position of Methyl Posttranscriptional Modifications on Nucleobase Stacking in RNA. Chemphyschem 2021; 22:1622-1630. [PMID: 34101319 DOI: 10.1002/cphc.202100333] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/30/2021] [Indexed: 01/08/2023]
Abstract
DFT calculations are employed to quantify the influence of the presence, number, nature, and position of posttranscriptional methylation on stacking strength of RNA bases. We carry out detailed potential energy scans of the variation in stacking energies with characteristic geometrical parameters in three categories of forty stacked dimers - canonical base homodimers (N||N), methylated base homodimers (mN||mN) and heterodimers of canonical bases and methylated counterparts (N||mN). Our analysis reveals that neutral methylation invariably enhances the stacking of bases. Further, N||mN stacking is stronger than mN||mN stacking and charged N||mN exhibit strongest stacking among all dimers. This indicates that methylations greatly enhance stacking when dispersed in RNA sequences containing identical bases. Comparison of stacks involving singly- and doubly-methylated purines reveal that incremental methylation enhances the stacking in neutral dimers. Although methylation at the carbon position of neutral pyrimidine dimers greatly enhances the stacking, methylation on the 5-membered ring imparts better stacking compared to methylation on the 6-membered ring in adenine dimers. However, methylation at the ring nitrogen (N1 ) provides better stacking than the amino group (N2 ) in guanine dimers. Our results thus highlight subtle structural effects of methylation on RNA base stacking and will enhance our understanding of the physicochemical principles of RNA structure and dynamics.
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Affiliation(s)
- Deepika Kagra
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - Amanpreet Singh Mahmi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
| | - N V Suresh Kumar
- Department of Humanities and Sciences (Physics), VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, 500090, India
| | - Preethi Seelam Prabhakar
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K3M4, Canada
| | - Purshotam Sharma
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India
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22
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Abstract
DNA dynamics can only be understood by taking into account its complex mechanical behavior at different length scales. At the micrometer level, the mechanical properties of single DNA molecules have been well-characterized by polymer models and are commonly quantified by a persistence length of 50 nm (~150 bp). However, at the base pair level (~3.4 Å), the dynamics of DNA involves complex molecular mechanisms that are still being deciphered. Here, we review recent single-molecule experiments and molecular dynamics simulations that are providing novel insights into DNA mechanics from such a molecular perspective. We first discuss recent findings on sequence-dependent DNA mechanical properties, including sequences that resist mechanical stress and sequences that can accommodate strong deformations. We then comment on the intricate effects of cytosine methylation and DNA mismatches on DNA mechanics. Finally, we review recently reported differences in the mechanical properties of DNA and double-stranded RNA, the other double-helical carrier of genetic information. A thorough examination of the recent single-molecule literature permits establishing a set of general 'rules' that reasonably explain the mechanics of nucleic acids at the base pair level. These simple rules offer an improved description of certain biological systems and might serve as valuable guidelines for future design of DNA and RNA nanostructures.
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23
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Krassovsky K, Ghosh RP, Meyer BJ. Genome-wide profiling reveals functional interplay of DNA sequence composition, transcriptional activity, and nucleosome positioning in driving DNA supercoiling and helix destabilization in C. elegans. Genome Res 2021; 31:1187-1202. [PMID: 34168009 PMCID: PMC8256864 DOI: 10.1101/gr.270082.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 05/25/2021] [Indexed: 12/11/2022]
Abstract
DNA topology and alternative DNA structures are implicated in regulating diverse biological processes. Although biomechanical properties of these structures have been studied extensively in vitro, characterization in vivo, particularly in multicellular organisms, is limited. We devised new methods to map DNA supercoiling and single-stranded DNA in Caenorhabditis elegans embryos and diapause larvae. To map supercoiling, we quantified the incorporation of biotinylated psoralen into DNA using high-throughput sequencing. To map single-stranded DNA, we combined permanganate treatment with genome-wide sequencing of induced double-stranded breaks. We found high levels of negative supercoiling at transcription start sites (TSSs) in embryos. GC-rich regions flanked by a sharp GC-to-AT transition delineate boundaries of supercoil propagation. In contrast to TSSs in embryos, TSSs in diapause larvae showed dramatic reductions in negative supercoiling without concomitant attenuation of transcription, suggesting developmental-stage-specific regulation. To assess whether alternative DNA structures control chromosome architecture and gene expression, we examined DNA supercoiling in the context of X-Chromosome dosage compensation. We showed that the condensin dosage compensation complex creates negative supercoils locally at its highest-occupancy binding sites but found no evidence for large-scale supercoiling domains along X Chromosomes. In contrast to transcription-coupled negative supercoiling, single-strandedness, which is most pronounced at transcript end sites, is dependent on high AT content and symmetrically positioned nucleosomes. We propose that sharp transitions in sequence composition at functional genomic elements constitute a common regulatory code and that DNA structure and propagation of torsional stress at regulatory elements are critical parameters in shaping important developmental events.
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Affiliation(s)
- Kristina Krassovsky
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204, USA
| | - Rajarshi P Ghosh
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204, USA
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3204, USA
| | - Barbara J Meyer
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3204, USA
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720-3204, USA
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24
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Rausch C, Zhang P, Casas-Delucchi CS, Daiß JL, Engel C, Coster G, Hastert FD, Weber P, Cardoso MC. Cytosine base modifications regulate DNA duplex stability and metabolism. Nucleic Acids Res 2021; 49:12870-12894. [PMID: 34133727 PMCID: PMC8682791 DOI: 10.1093/nar/gkab509] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 05/26/2021] [Accepted: 06/03/2021] [Indexed: 12/14/2022] Open
Abstract
DNA base modifications diversify the genome and are essential players in development. Yet, their influence on DNA physical properties and the ensuing effects on genome metabolism are poorly understood. Here, we focus on the interplay of cytosine modifications and DNA processes. We show by a combination of in vitro reactions with well-defined protein compositions and conditions, and in vivo experiments within the complex networks of the cell that cytosine methylation stabilizes the DNA helix, increasing its melting temperature and reducing DNA helicase and RNA/DNA polymerase speed. Oxidation of methylated cytosine, however, reverts the duplex stabilizing and genome metabolic effects to the level of unmodified cytosine. We detect this effect with DNA replication and transcription proteins originating from different species, ranging from prokaryotic and viral to the eukaryotic yeast and mammalian proteins. Accordingly, lack of cytosine methylation increases replication fork speed by enhancing DNA helicase unwinding speed in cells. We further validate that this cannot simply be explained by altered global DNA decondensation, changes in histone marks or chromatin structure and accessibility. We propose that the variegated deposition of cytosine modifications along the genome regulates DNA helix stability, thereby providing an elementary mechanism for local fine-tuning of DNA metabolism.
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Affiliation(s)
- Cathia Rausch
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Peng Zhang
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany.,Center for Tissue Engineering and Stem Cell Research, Guizhou Medical University, Guiyang, Guizhou 550004, China
| | | | - Julia L Daiß
- Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Christoph Engel
- Regensburg Center for Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Gideon Coster
- Chester Beatty Laboratories, The Institute of Cancer Research, London SW3 6JB, UK
| | - Florian D Hastert
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Patrick Weber
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
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25
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Gautam P, Kumar Sinha S. Anticipating response function in gene regulatory networks. J R Soc Interface 2021; 18:20210206. [PMID: 34062105 DOI: 10.1098/rsif.2021.0206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The origin of an ordered genetic response of a complex and noisy biological cell is intimately related to the detailed mechanism of protein-DNA interactions present in a wide variety of gene regulatory (GR) systems. However, the quantitative prediction of genetic response and the correlation between the mechanism and the response curve is poorly understood. Here, we report in silico binding studies of GR systems to show that the transcription factor (TF) binds to multiple DNA sites with high cooperativity spreads from specific binding sites into adjacent non-specific DNA and bends the DNA. Our analysis is not limited only to the isolated model system but also can be applied to a system containing multiple interacting genes. The controlling role of TF oligomerization, TF-ligand interactions, and DNA looping for gene expression has been also characterized. The predictions are validated against detailed grand canonical Monte Carlo simulations and published data for the lac operon system. Overall, our study reveals that the expression of target genes can be quantitatively controlled by modulating TF-ligand interactions and the bending energy of DNA.
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Affiliation(s)
- Pankaj Gautam
- Theoretical and Computational Biophysical Chemistry Group, Department of Chemistry, Indian Institute of Technology, Ropar 140001, India
| | - Sudipta Kumar Sinha
- Theoretical and Computational Biophysical Chemistry Group, Department of Chemistry, Indian Institute of Technology, Ropar 140001, India
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26
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Single-molecule micromanipulation studies of methylated DNA. Biophys J 2021; 120:2148-2155. [PMID: 33838135 DOI: 10.1016/j.bpj.2021.03.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/31/2022] Open
Abstract
Cytosine methylated at the five-carbon position is the most widely studied reversible DNA modification. Prior findings indicate that methylation can alter mechanical properties. However, those findings were qualitative and sometimes contradictory, leaving many aspects unclear. By applying single-molecule magnetic force spectroscopy techniques allowing for direct manipulation and dynamic observation of DNA mechanics and mechanically driven strand separation, we investigated how CpG and non-CpG cytosine methylation affects DNA micromechanical properties. We quantitatively characterized DNA stiffness using persistence length measurements from force-extension curves in the nanoscale length regime and demonstrated that cytosine methylation results in longer contour length and increased DNA flexibility (i.e., decreased persistence length). In addition, we observed the preferential formation of plectonemes over unwound single-stranded "bubbles" of DNA under physiologically relevant stretching forces and supercoiling densities. The flexibility and high structural stability of methylated DNA is likely to have significant consequences on the recruitment of proteins recognizing cytosine methylation and DNA packaging.
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27
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Basu A, Bobrovnikov DG, Ha T. DNA mechanics and its biological impact. J Mol Biol 2021; 433:166861. [PMID: 33539885 DOI: 10.1016/j.jmb.2021.166861] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 02/06/2023]
Abstract
Almost all nucleoprotein interactions and DNA manipulation events involve mechanical deformations of DNA. Extraordinary progresses in single-molecule, structural, and computational methods have characterized the average mechanical properties of DNA, such as bendability and torsional rigidity, in high resolution. Further, the advent of sequencing technology has permitted measuring, in high-throughput, how such mechanical properties vary with sequence and epigenetic modifications along genomes. We review these recent technological advancements, and discuss how they have contributed to the emerging idea that variations in the mechanical properties of DNA play a fundamental role in regulating, genome-wide, diverse processes involved in chromatin organization.
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Affiliation(s)
- Aakash Basu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Dmitriy G Bobrovnikov
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Baltimore, MD 21205, USA
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28
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Tsuruta M, Sugitani Y, Sugimoto N, Miyoshi D. Combined Effects of Methylated Cytosine and Molecular Crowding on the Thermodynamic Stability of DNA Duplexes. Int J Mol Sci 2021; 22:ijms22020947. [PMID: 33477917 PMCID: PMC7833394 DOI: 10.3390/ijms22020947] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/31/2022] Open
Abstract
Methylated cytosine within CpG dinucleotides is a key factor for epigenetic gene regulation. It has been revealed that methylated cytosine decreases DNA backbone flexibility and increases the thermal stability of DNA. Although the molecular environment is an important factor for the structure, thermodynamics, and function of biomolecules, there are few reports on the effects of methylated cytosine under a cell-mimicking molecular environment. Here, we systematically investigated the effects of methylated cytosine on the thermodynamics of DNA duplexes under molecular crowding conditions, which is a critical difference between the molecular environment in cells and test tubes. Thermodynamic parameters quantitatively demonstrated that the methylation effect and molecular crowding effect on DNA duplexes are independent and additive, in which the degree of the stabilization is the sum of the methylation effect and molecular crowding effect. Furthermore, the effects of methylation and molecular crowding correlate with the hydration states of DNA duplexes. The stabilization effect of methylation was due to the favorable enthalpic contribution, suggesting that direct interactions of the methyl group with adjacent bases and adjacent methyl groups play a role in determining the flexibility and thermodynamics of DNA duplexes. These results are useful to predict the properties of DNA duplexes with methylation in cell-mimicking conditions.
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Affiliation(s)
- Mitsuki Tsuruta
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
| | - Yui Sugitani
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
| | - Naoki Sugimoto
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe 650-0047, Japan
| | - Daisuke Miyoshi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (M.T.); (Y.S.); (N.S.)
- Correspondence: ; Tel.: +81-(07)-8303-1426
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Kameda T, Suzuki MM, Awazu A, Togashi Y. Structural dynamics of DNA depending on methylation pattern. Phys Rev E 2021; 103:012404. [PMID: 33601517 DOI: 10.1103/physreve.103.012404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
DNA methylation is associated with a number of biological phenomena, and plays crucial roles in epigenetic regulation of eukaryotic gene expression. It is also suggested that DNA methylation alters the mechanical properties of DNA molecules, which is likely to affect epigenetic regulation. However, it has not been systematically investigated how methylation changes the structural and dynamic features of DNA. In this research, to elucidate the effects of methylation on DNA mechanics, a fully atomic molecular dynamics simulation of double-stranded DNA with several methylation patterns was performed. Through the analysis of the relative positioning of the nucleotides (base-step variables), characteristic changes in terms of local flexibility were observed, which further affected the overall DNA geometry and stiffness. These findings may serve as a basis for a discussion on methylation-dependent DNA dynamics in physiological conditions.
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Affiliation(s)
- Takeru Kameda
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- RIKEN Center for Biosystems Dynamics Research (BDR), Wako, Saitama, Japan
| | - Miho M Suzuki
- Graduate School of Medicine, Nagoya University, Nagoya, Aichi, Japan
| | - Akinori Awazu
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Yuichi Togashi
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- Research Center for the Mathematics on Chromatin Live Dynamics (RcMcD), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- RIKEN Center for Biosystems Dynamics Research (BDR), Higashi-Hiroshima, Hiroshima, Japan
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30
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Saran R, Wang Y, Li ITS. Mechanical Flexibility of DNA: A Quintessential Tool for DNA Nanotechnology. SENSORS (BASEL, SWITZERLAND) 2020; 20:E7019. [PMID: 33302459 PMCID: PMC7764255 DOI: 10.3390/s20247019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/04/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
The mechanical properties of DNA have enabled it to be a structural and sensory element in many nanotechnology applications. While specific base-pairing interactions and secondary structure formation have been the most widely utilized mechanism in designing DNA nanodevices and biosensors, the intrinsic mechanical rigidity and flexibility are often overlooked. In this article, we will discuss the biochemical and biophysical origin of double-stranded DNA rigidity and how environmental and intrinsic factors such as salt, temperature, sequence, and small molecules influence it. We will then take a critical look at three areas of applications of DNA bending rigidity. First, we will discuss how DNA's bending rigidity has been utilized to create molecular springs that regulate the activities of biomolecules and cellular processes. Second, we will discuss how the nanomechanical response induced by DNA rigidity has been used to create conformational changes as sensors for molecular force, pH, metal ions, small molecules, and protein interactions. Lastly, we will discuss how DNA's rigidity enabled its application in creating DNA-based nanostructures from DNA origami to nanomachines.
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Affiliation(s)
- Runjhun Saran
- Department of Chemistry, Biochemistry and Molecular Biology, Irving K. Barber Faculty of Science, The University of British Columbia, Kelowna, BC V1V1V7, Canada;
| | - Yong Wang
- Department of Physics, Materials Science and Engineering Program, Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA;
| | - Isaac T. S. Li
- Department of Chemistry, Biochemistry and Molecular Biology, Irving K. Barber Faculty of Science, The University of British Columbia, Kelowna, BC V1V1V7, Canada;
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31
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What do we know about DNA mechanics so far? Curr Opin Struct Biol 2020; 64:42-50. [DOI: 10.1016/j.sbi.2020.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/17/2020] [Indexed: 12/14/2022]
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32
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Ovando‐Vázquez C, Salgado‐Blanco D, López‐Urías F. Nanoscale Properties of the Methylation in GpC Dinucleotide Systems. ChemistrySelect 2020. [DOI: 10.1002/slct.202001014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Cesaré Ovando‐Vázquez
- Centro Nacional de Supercómputo, IPICyTCátedra-Conacyt Camino a la Presa San José 2055, Col Lomas 4a sección, San Luis Potosí S.L.P. 78216 México
- División de Biología Molecular, IPICyT Camino a la Presa San José 2055, Col Lomas 4a sección San Luis Potosí S.L.P. 78216 México
| | - Daniel Salgado‐Blanco
- Centro Nacional de Supercómputo, IPICyTCátedra-Conacyt Camino a la Presa San José 2055, Col Lomas 4a sección, San Luis Potosí S.L.P. 78216 México
- División de Materiales Avanzados, IPICyT Camino a la Presa San José 2055, Col Lomas 4a sección, San Luis Potosí S.L.P. 78216, México
| | - Florentino López‐Urías
- División de Materiales Avanzados, IPICyT Camino a la Presa San José 2055, Col Lomas 4a sección, San Luis Potosí S.L.P. 78216, México
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Abramov G, Velyvis A, Rennella E, Wong LE, Kay LE. A methyl-TROSY approach for NMR studies of high-molecular-weight DNA with application to the nucleosome core particle. Proc Natl Acad Sci U S A 2020; 117:12836-12846. [PMID: 32457157 PMCID: PMC7293644 DOI: 10.1073/pnas.2004317117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The development of methyl-transverse relaxation-optimized spectroscopy (methyl-TROSY)-based NMR methods, in concert with robust strategies for incorporation of methyl-group probes of structure and dynamics into the protein of interest, has facilitated quantitative studies of high-molecular-weight protein complexes. Here we develop a one-pot in vitro reaction for producing NMR quantities of methyl-labeled DNA at the C5 and N6 positions of cytosine (5mC) and adenine (6mA) nucleobases, respectively, enabling the study of high-molecular-weight DNA molecules using TROSY approaches originally developed for protein applications. Our biosynthetic strategy exploits the large number of naturally available methyltransferases to specifically methylate DNA at a desired number of sites that serve as probes of structure and dynamics. We illustrate the methodology with studies of the 153-base pair Widom DNA molecule that is simultaneously methyl-labeled at five sites, showing that high-quality 13C-1H spectra can be recorded on 100 μM samples in a few minutes. NMR spin relaxation studies of labeled methyl groups in both DNA and the H2B histone protein component of the 200-kDa nucleosome core particle (NCP) establish that methyl groups at 5mC and 6mA positions are, in general, more rigid than Ile, Leu, and Val methyl probes in protein side chains. Studies focusing on histone H2B of NCPs wrapped with either wild-type DNA or DNA methylated at all 26 CpG sites highlight the utility of NMR in investigating the structural dynamics of the NCP and how its histone core is affected through DNA methylation, an important regulator of transcription.
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Affiliation(s)
- Gili Abramov
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Algirdas Velyvis
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Bioscience Department, Syngenta, Jealott's Hill Research Centre, Bracknell RG42 6EY, United Kingdom
| | - Enrico Rennella
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Leo E Wong
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lewis E Kay
- Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada;
- Department of Biochemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 1A8, Canada
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
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Abstract
Antiviral drugs have traditionally been developed by directly targeting essential viral components. However, this strategy often fails due to the rapid generation of drug-resistant viruses. Recent genome-wide approaches, such as those employing small interfering RNA (siRNA) or clustered regularly interspaced short palindromic repeats (CRISPR) or those using small molecule chemical inhibitors targeting the cellular "kinome," have been used successfully to identify cellular factors that can support virus replication. Since some of these cellular factors are critical for virus replication, but are dispensable for the host, they can serve as novel targets for antiviral drug development. In addition, potentiation of immune responses, regulation of cytokine storms, and modulation of epigenetic changes upon virus infections are also feasible approaches to control infections. Because it is less likely that viruses will mutate to replace missing cellular functions, the chance of generating drug-resistant mutants with host-targeted inhibitor approaches is minimized. However, drug resistance against some host-directed agents can, in fact, occur under certain circumstances, such as long-term selection pressure of a host-directed antiviral agent that can allow the virus the opportunity to adapt to use an alternate host factor or to alter its affinity toward the target that confers resistance. This review describes novel approaches for antiviral drug development with a focus on host-directed therapies and the potential mechanisms that may account for the acquisition of antiviral drug resistance against host-directed agents.
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35
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Chen YT, Yang H, Chu JW. Structure-mechanics statistical learning unravels the linkage between local rigidity and global flexibility in nucleic acids. Chem Sci 2020; 11:4969-4979. [PMID: 34122953 PMCID: PMC8159235 DOI: 10.1039/d0sc00480d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The mechanical properties of nucleic acids underlie biological processes ranging from genome packaging to gene expression, but tracing their molecular origin has been difficult due to the structural and chemical complexity. We posit that concepts from machine learning can help to tackle this long-standing challenge. Here, we demonstrate the feasibility and advantage of this strategy through developing a structure-mechanics statistical learning scheme to elucidate how local rigidity in double-stranded (ds)DNA and dsRNA may lead to their global flexibility in bend, stretch, and twist. Specifically, the mechanical parameters in a heavy-atom elastic network model are computed from the trajectory data of all-atom molecular dynamics simulation. The results show that the inter-atomic springs for backbone and ribose puckering in dsRNA are stronger than those in dsDNA, but are similar in strengths for base-stacking and base-pairing. Our analysis shows that the experimental observation of dsDNA being easier to bend but harder to stretch than dsRNA comes mostly from the respective B- and A-form topologies. The computationally resolved composition of local rigidity indicates that the flexibility of both nucleic acids is mostly due to base-stacking. But for properties like twist-stretch coupling, backbone springs are shown to play a major role instead. The quantitative connection between local rigidity and global flexibility sets foundation for understanding how local binding and chemical modification of genetic materials effectuate longer-ranged regulatory signals. The mechanical properties of nucleic acids underlie biological processes ranging from genome packaging to gene expression. We devise structural mechanics statistical learning method to reveal their molecular origin in terms of chemical interactions.![]()
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Affiliation(s)
- Yi-Tsao Chen
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University Hsinchu Taiwan 30068 Republic of China
| | - Haw Yang
- Department of Chemistry, Princeton University Princeton NJ 08544 USA
| | - Jhih-Wei Chu
- Institute of Bioinformatics and Systems Biology, Department of Biological Science and Technology, Institute of Molecular Medicine and Bioengineering, National Chiao Tung University Hsinchu Taiwan 30068 Republic of China +886 3 5712121 ext. 56996
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36
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Xing Y, Gong R, Xu Y, Liu K, Zhou M. Codon usage bias affects α-amylase mRNA level by altering RNA stability and cytosine methylation patterns in Escherichia coli. Can J Microbiol 2020; 66:521-528. [PMID: 32259457 DOI: 10.1139/cjm-2019-0624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Codon usage bias exists in almost every organism and is reported to regulate protein translation efficiency and folding. Besides translation, the preliminary role of codon usage bias on gene transcription has also been revealed in some eukaryotes such as Neurospora crassa. In this study, we took as an example the α-amylase-coding gene (amyA) and examined the role of codon usage bias in regulating gene expression in the typical prokaryote Escherichia coli. We confirmed the higher translation efficiency on codon-optimized amyA RNAs and found that the RNA level itself was also affected by codon optimization. The decreased RNA level was caused at least in part by altered mRNA stability at the post-transcriptional level. Codon optimization also altered the number of cytosine methylation sites. Examination on dcm knockouts suggested that cytosine methylation may be a minor mechanism adopted by codon bias to regulate gene RNA levels. More studies are required to verify the global effect of codon usage and to reveal its detailed mechanism on transcription.
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Affiliation(s)
- Yanzi Xing
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Ruiqing Gong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Yichun Xu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Kunshan Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
| | - Mian Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China
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37
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Claudio-Piedras F, Recio-Tótoro B, Condé R, Hernández-Tablas JM, Hurtado-Sil G, Lanz-Mendoza H. DNA Methylation in Anopheles albimanus Modulates the Midgut Immune Response Against Plasmodium berghei. Front Immunol 2020; 10:3025. [PMID: 31993053 PMCID: PMC6970940 DOI: 10.3389/fimmu.2019.03025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022] Open
Abstract
Epigenetic mechanisms such as DNA methylation and histone post-translational modifications are fundamental for the phenotypic plasticity of insects during their interaction with the environment. In response to environmental cues, the methylation pattern in DNA is dynamically remodeled to achieve an epigenetic control of gene expression. DNA methylation is the focus of study in insects for its evolutionarily conserved character; however, there is scant knowledge about the epigenetic regulation in vector mosquitoes, especially during their infection by parasites. The aim of the present study was to evaluate the participation of DNA methylation in the immune response of Anopheles albimanus to a Plasmodium infection. For this, we first investigated the presence of a fully functional DNA methylation system in A. albimanus by assessing its potential role in larval development. Subsequently, we evaluated the transcriptional response to Plasmodium berghei of two mosquito phenotypes with different degrees of susceptibility to the parasite, in a scenario where their global DNA methylation had been pharmacologically inhibited. Our study revealed that A. albimanus has a functional DNA methylation system that is essential to larval viability, and that is also responsive to feeding and parasite challenges. The pharmacological erasure of the methylome with azacytidine or decitabine abolished the divergent responses of both mosquito phenotypes, leading to a transcriptionally similar response upon parasite challenge. This response was more specific, and the infection load in both phenotypes was lowered. Our findings suggest that DNA methylation may constitute a key factor in vector competence, and a promising target for preventing malaria transmission.
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Affiliation(s)
| | | | | | | | | | - Humberto Lanz-Mendoza
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
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38
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Abstract
Cytosine methylation as a reversible chromatin mark has been investigated extensively for its influence on gene silencing and the regulation of its dynamic association-disassociation at specific sites within a eukaryotic genome. With the remarkable reductions in cost and time associated with whole-genome DNA sequence analysis, coupled with the high fidelity of bisulfite-treated DNA sequencing, single nucleotide resolution of cytosine methylation repatterning within even very large genomes is increasingly achievable. What remains a challenge is the analysis of genome-wide methylome datasets and, consequently, a clear understanding of the overall influence of methylation repatterning on gene expression or vice versa. Reported data have sometimes been subject to stringent data filtering methods that can serve to skew downstream biological interpretation. These complications derive from methylome analysis procedures that vary widely in method and parameter setting. DNA methylation as a chromatin feature that influences DNA stability can be dynamic and rapidly responsive to environmental change. Consequently, methods to discriminate background "noise" of the system from biological signal in response to specific perturbation is essential in some types of experiments. We describe numerous aspects of whole-genome bisulfite sequence data that must be contemplated as well as the various steps of methylome data analysis which impact the biological interpretation of the final output.
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39
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DNA Modification Readers and Writers and Their Interplay. J Mol Biol 2019:S0022-2836(19)30718-1. [PMID: 31866298 DOI: 10.1016/j.jmb.2019.12.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/28/2019] [Accepted: 12/05/2019] [Indexed: 12/15/2022]
Abstract
Genomic DNA is modified in a postreplicative manner and several modifications, the enzymes responsible for their deposition as well as proteins that read these modifications, have been described. Here, we focus on the impact of DNA modifications on the DNA helix and review the writers and readers of cytosine modifications and how they interplay to shape genome composition, stability, and function.
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40
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Sanchez R, Yang X, Maher T, Mackenzie SA. Discrimination of DNA Methylation Signal from Background Variation for Clinical Diagnostics. Int J Mol Sci 2019; 20:E5343. [PMID: 31717838 PMCID: PMC6862328 DOI: 10.3390/ijms20215343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/09/2019] [Accepted: 10/24/2019] [Indexed: 12/29/2022] Open
Abstract
Advances in the study of human DNA methylation variation offer a new avenue for the translation of epigenetic research results to clinical applications. Although current approaches to methylome analysis have been helpful in revealing an epigenetic influence in major human diseases, this type of analysis has proven inadequate for the translation of these advances to clinical diagnostics. As in any clinical test, the use of a methylation signal for diagnostic purposes requires the estimation of an optimal cutoff value for the signal, which is necessary to discriminate a signal induced by a disease state from natural background variation. To address this issue, we propose the application of a fundamental signal detection theory and machine learning approaches. Simulation studies and tests of two available methylome datasets from autism and leukemia patients demonstrate the feasibility of this approach in clinical diagnostics, providing high discriminatory power for the methylation signal induced by disease, as well as high classification performance. Specifically, the analysis of whole biomarker genomic regions could suffice for a diagnostic, markedly decreasing its cost.
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Affiliation(s)
- Robersy Sanchez
- Departments of Biology and Plant Science, The Pennsylvania State University, University Park, PA 16802, USA; (X.Y.); (T.M.)
| | | | | | - Sally A. Mackenzie
- Departments of Biology and Plant Science, The Pennsylvania State University, University Park, PA 16802, USA; (X.Y.); (T.M.)
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41
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Abstract
The first crucial step in the developmental program occurs during pre-implantation, the time after the oocyte has been fertilized and before the embryo implants in the uterus. This period represents a vulnerable window as the epigenome undergoes dynamic changes in DNA methylation profiles. Alterations in the early embryonic reprogramming wave can impair DNA methylation patterns and induce permanent changes to the developmental program, leading to the onset of adverse health outcomes in offspring. Although there is an increasing body of evidence indicating that harmful exposures during pre-implantation embryo development can trigger lasting epigenetic alterations in offspring, the mechanisms are still not fully understood. Since physiological or pathological changes in DNA methylation can occur as a response to environmental cues, proper environmental milieu plays a critical role in the success of embryonic development. In this review, we depict the mechanisms behind the embryonic epigenetic reprogramming of DNA methylation and highlight how maternal environmental stressors (e.g., alcohol, heat stress, nutrient availability) during pre-implantation and assisted reproductive technology procedures affect development and DNA methylation marks.
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Affiliation(s)
- Mélanie Breton-Larrivée
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Research Center of the CHU Sainte-Justine. Montreal, Canada
| | - Elizabeth Elder
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Research Center of the CHU Sainte-Justine. Montreal, Canada
| | - Serge McGraw
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Research Center of the CHU Sainte-Justine. Montreal, Canada.,Department of Obstetrics & Gynecology, Université de Montréal, Research Center of the CHU Sainte-Justine, Montréal, Canada
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42
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Lipiec E, Ruggeri FS, Benadiba C, Borkowska AM, Kobierski JD, Miszczyk J, Wood BR, Deacon GB, Kulik A, Dietler G, Kwiatek WM. Infrared nanospectroscopic mapping of a single metaphase chromosome. Nucleic Acids Res 2019; 47:e108. [PMID: 31562528 PMCID: PMC6765102 DOI: 10.1093/nar/gkz630] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 07/07/2019] [Accepted: 07/13/2019] [Indexed: 01/27/2023] Open
Abstract
The integrity of the chromatin structure is essential to every process occurring within eukaryotic nuclei. However, there are no reliable tools to decipher the molecular composition of metaphase chromosomes. Here, we have applied infrared nanospectroscopy (AFM-IR) to demonstrate molecular difference between eu- and heterochromatin and generate infrared maps of single metaphase chromosomes revealing detailed information on their molecular composition, with nanometric lateral spatial resolution. AFM-IR coupled with principal component analysis has confirmed that chromosome areas containing euchromatin and heterochromatin are distinguishable based on differences in the degree of methylation. AFM-IR distribution of eu- and heterochromatin was compared to standard fluorescent staining. We demonstrate the ability of our methodology to locate spatially the presence of anticancer drug sites in metaphase chromosomes and cellular nuclei. We show that the anticancer 'rule breaker' platinum compound [Pt[N(p-HC6F4)CH2]2py2] preferentially binds to heterochromatin, forming localized discrete foci due to condensation of DNA interacting with the drug. Given the importance of DNA methylation in the development of nearly all types of cancer, there is potential for infrared nanospectroscopy to be used to detect gene expression/suppression sites in the whole genome and to become an early screening tool for malignancy.
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Affiliation(s)
- Ewelina Lipiec
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Centre for Biospectroscopy and School of Chemistry, Monash University, 3800 Victoria, Australia
| | - Francesco S Ruggeri
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Department of Chemistry, University of Cambridge, CB21EW, UK
| | - Carine Benadiba
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Anna M Borkowska
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Jan D Kobierski
- Department of Pharmaceutical Biophysics, Faculty of Pharmacy Jagiellonian University Medical College, PL-31007 Cracow, Poland
| | - Justyna Miszczyk
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
| | - Bayden R Wood
- Centre for Biospectroscopy and School of Chemistry, Monash University, 3800 Victoria, Australia
| | - Glen B Deacon
- School of Chemistry, Faculty of Science, Monash University, 3800 Victoria, Australia
| | - Andrzej Kulik
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Giovanni Dietler
- Institute of Physics, Laboratory of Physics of Living Matter, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Wojciech M Kwiatek
- Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
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Liebl K, Zacharias M. How methyl-sugar interactions determine DNA structure and flexibility. Nucleic Acids Res 2019; 47:1132-1140. [PMID: 30541032 PMCID: PMC6379717 DOI: 10.1093/nar/gky1237] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/26/2018] [Accepted: 11/30/2018] [Indexed: 12/18/2022] Open
Abstract
The sequence dependent structure and flexibility of the DNA double helix is of key importance for gene expression and DNA packing and it can be modulated by DNA modifications. The presence of a C5′-methyl group in thymine or the frequent C5′-methylated-cytosine affects the DNA fine structure, however, the underlying mechanism and steric origins have remained largely unexplained. Employing Molecular Dynamics free energy simulations that allow switching on or off interactions with the methyl groups in several DNA sequences, we systematically identified the physical origin of the coupling between methyl groups and DNA backbone fine structure. Whereas methyl-solvent and methyl–nucleobase interactions were found to be of minor importance, the methyl group interaction with the 5′ neighboring sugar was identified as main cause for influencing the population of backbone substates. The sterical methyl sugar clash prevents the formation of unconventional stabilizing hydrogen bonds between nucleobase and backbone. The technique was also used to study the contribution of methyl groups to DNA flexibility and served to explain why the presence of methyl sugar clashes in thymine and methyl-cytosine can result in an overall local increase of DNA flexibility.
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Affiliation(s)
- Korbinian Liebl
- Physics Department T38, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Martin Zacharias
- Physics Department T38, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
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44
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Hognon C, Besancenot V, Gruez A, Grandemange S, Monari A. Cooperative Effects of Cytosine Methylation on DNA Structure and Dynamics. J Phys Chem B 2019; 123:7365-7371. [PMID: 31365827 DOI: 10.1021/acs.jpcb.9b05835] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The behavior of the structural parameters of DNA considering different levels of methylation in CpG islands is studied by means of full-atom molecular dynamics simulations and electronic circular dichroism, both in an artificial model system and in a gene promoter sequence. It is demonstrated that methylation although intrinsically brings quite local perturbations may, if its level is high enough, induce cooperative effects that strongly modify the DNA backbone torsional parameters altering the helicity as compared to the nonmethylated case. Because methylation of the CpG island is correlated with the regulation of gene expression, understanding the structural modifications induced in DNA is crucial to characterize all the fine equilibria into play in epigenetics phenomena.
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Affiliation(s)
- Cécilia Hognon
- Université de Lorraine and CNRS, UMR 7019 LPCT , F-54000 Nancy , France
| | | | - Arnaud Gruez
- Université de Lorraine and CNRS, UMR 7356 IMOPA , F-54000 Nancy , France
| | | | - Antonio Monari
- Université de Lorraine and CNRS, UMR 7019 LPCT , F-54000 Nancy , France
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45
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Teng X, Hwang W. Effect of Methylation on Local Mechanics and Hydration Structure of DNA. Biophys J 2019; 114:1791-1803. [PMID: 29694859 DOI: 10.1016/j.bpj.2018.03.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/03/2018] [Accepted: 03/14/2018] [Indexed: 12/31/2022] Open
Abstract
Cytosine methylation affects mechanical properties of DNA and potentially alters the hydration fingerprint for recognition by proteins. The atomistic origin for these effects is not well understood, and we address this via all-atom molecular dynamics simulations. We find that the stiffness of the methylated dinucleotide step changes marginally, whereas the neighboring steps become stiffer. Stiffening is further enhanced for consecutively methylated steps, providing a mechanistic origin for the effect of hypermethylation. Steric interactions between the added methyl groups and the nonpolar groups of the neighboring nucleotides are responsible for the stiffening in most cases. By constructing hydration maps, we found that methylation also alters the surface hydration structure in distinct ways. Its resistance to deformation may contribute to the stiffening of DNA for deformational modes lacking steric interactions. These results highlight the sequence- and deformational-mode-dependent effects of cytosine methylation.
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Affiliation(s)
- Xiaojing Teng
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas; Department of Materials Science & Engineering, Texas A&M University, College Station, Texas; School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Korea.
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46
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Estibariz I, Overmann A, Ailloud F, Krebes J, Josenhans C, Suerbaum S. The core genome m5C methyltransferase JHP1050 (M.Hpy99III) plays an important role in orchestrating gene expression in Helicobacter pylori. Nucleic Acids Res 2019; 47:2336-2348. [PMID: 30624738 PMCID: PMC6412003 DOI: 10.1093/nar/gky1307] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 12/20/2022] Open
Abstract
Helicobacter pylori encodes a large number of restriction-modification (R-M) systems despite its small genome. R-M systems have been described as 'primitive immune systems' in bacteria, but the role of methylation in bacterial gene regulation and other processes is increasingly accepted. Every H. pylori strain harbours a unique set of R-M systems resulting in a highly diverse methylome. We identified a highly conserved GCGC-specific m5C MTase (JHP1050) that was predicted to be active in all of 459 H. pylori genome sequences analyzed. Transcriptome analysis of two H. pylori strains and their respective MTase mutants showed that inactivation of the MTase led to changes in the expression of 225 genes in strain J99, and 29 genes in strain BCM-300. Ten genes were differentially expressed in both mutated strains. Combining bioinformatic analysis and site-directed mutagenesis, we demonstrated that motifs overlapping the promoter influence the expression of genes directly, while methylation of other motifs might cause secondary effects. Thus, m5C methylation modifies the transcription of multiple genes, affecting important phenotypic traits that include adherence to host cells, natural competence for DNA uptake, bacterial cell shape, and susceptibility to copper.
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Affiliation(s)
- Iratxe Estibariz
- Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, München, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Munich Site, Munich, Germany
| | - Annemarie Overmann
- Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, München, Germany
| | - Florent Ailloud
- Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, München, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Munich Site, Munich, Germany
| | - Juliane Krebes
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
| | - Christine Josenhans
- Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, München, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Munich Site, Munich, Germany
| | - Sebastian Suerbaum
- Medical Microbiology and Hospital Epidemiology, Max von Pettenkofer Institute, Faculty of Medicine, LMU Munich, München, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Munich Site, Munich, Germany
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47
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Bergues-Pupo AE, Goktas M, Tunn I, Lopez-Garcia P, Vila Verde A, Blank KG, Valleriani A. Goodness of fit testing in dynamic single-molecule force spectroscopy. J Chem Phys 2018; 149:244120. [PMID: 30599724 DOI: 10.1063/1.5055071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Dynamic single-molecule force spectroscopy (SMFS) is a powerful method to characterize the mechanical stability of biomolecules. We address the problem that the standard manner of reporting the extracted energy landscape parameters does not reveal the intrinsic statistical errors associated with them. This problem becomes particularly relevant when SMFS is used to compare two or more different molecular systems. Here, we propose two methods that allow for a straightforward test of statistical significance. We illustrate the power of the methods by applying them to the experimental results obtained for three dimeric coiled coils of different lengths. Both methods are general and may be applied to any problem involving the fit of models with two correlated parameters.
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Affiliation(s)
- Ana E Bergues-Pupo
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, 14424 Potsdam, Germany
| | - Melis Goktas
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, 14424 Potsdam, Germany
| | - Isabell Tunn
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, 14424 Potsdam, Germany
| | - Patricia Lopez-Garcia
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, 14424 Potsdam, Germany
| | - Ana Vila Verde
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, 14424 Potsdam, Germany
| | - Kerstin G Blank
- Max Planck Institute of Colloids and Interfaces, Mechano(bio)chemistry, 14424 Potsdam, Germany
| | - Angelo Valleriani
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, 14424 Potsdam, Germany
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48
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Epigenetically reprogrammed methylation landscape drives the DNA self-assembly and serves as a universal cancer biomarker. Nat Commun 2018; 9:4915. [PMID: 30514834 PMCID: PMC6279781 DOI: 10.1038/s41467-018-07214-w] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 10/21/2018] [Indexed: 02/02/2023] Open
Abstract
Epigenetic reprogramming in cancer genomes creates a distinct methylation landscape encompassing clustered methylation at regulatory regions separated by large intergenic tracks of hypomethylated regions. This methylation landscape that we referred to as Methylscape is displayed by most cancer types, thus may serve as a universal cancer biomarker. To-date most research has focused on the biological consequences of DNA Methylscape changes whereas its impact on DNA physicochemical properties remains unexplored. Herein, we examine the effect of levels and genomic distribution of methylcytosines on the physicochemical properties of DNA to detect the Methylscape biomarker. We find that DNA polymeric behaviour is strongly affected by differential patterning of methylcytosine, leading to fundamental differences in DNA solvation and DNA-gold affinity between cancerous and normal genomes. We exploit these Methylscape differences to develop simple, highly sensitive and selective electrochemical or colorimetric one-step assays for the detection of cancer. These assays are quick, i.e., analysis time ≤10 minutes, and require minimal sample preparation and small DNA input. DNA methylation is an epigenetic modification that control genetic programs. Here, the authors found that the methylation landscape influences the physicochemical properties of DNA and that it can serve as a universal cancer biomarker, and developed a one-step assay for the detection of cancer DNA.
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49
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Garafutdinov RR, Galimova AA, Sakhabutdinova AR. The influence of CpG (5'-d(CpG)-3' dinucleotides) methylation on ultrasonic DNA fragmentation. J Biomol Struct Dyn 2018; 37:3877-3886. [PMID: 30351231 DOI: 10.1080/07391102.2018.1533888] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
DNA methylation is an important way of gene regulation. The variety of methods for DNA methylation analysis based on chemical modification or enzyme digestion has been proposed. However, DNA is able to undergo transformations under physical power. Here, we report that the cytosine methylation in CpG dinucleotides determines the difference in fragmentation rate of methylated and unmethylated DNA under sonication. We found that at the beginning of sonication, methylated DNAs are degraded faster than unmethylated one, and the difference in fragmentation degree can be evaluated with high reliability by quantitative polymerase chain reaction (qPCR). The optimal parameters that provide the greatest difference in amount of amplifiable DNA targets corresponding to fragmentation degree are the following: moderate amplicon size (about 150-250 bp), medium CpG sparseness (one CpG dinucleotide per ∼12-14 nucleotides of the chain), and short sonication time (less than 5 min). Along with CpG, the CpA and CpT contents of amplified regions should be taken into account for proper DNA fragmentation by ultrasound as well. The obtained data could be used for elaboration of a method for comparative methylation testing, when there is no need to detect methylation of certain CpG dinucleotides. This method will be simple (can be used by any technician familiar with PCR), low cost (no need to use an expensive reagents), and fast (only brief DNA sonication and conventional qPCR are carried out). Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ravil R Garafutdinov
- a Institute of Biochemistry and Genetics, Ufa Federal Research Centre, Russian Academy of Sciences , Ufa , Bashkortostan , Russia
| | - Aizilya A Galimova
- a Institute of Biochemistry and Genetics, Ufa Federal Research Centre, Russian Academy of Sciences , Ufa , Bashkortostan , Russia
| | - Assol R Sakhabutdinova
- a Institute of Biochemistry and Genetics, Ufa Federal Research Centre, Russian Academy of Sciences , Ufa , Bashkortostan , Russia
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50
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Krupa P, Wales DJ, Sieradzan AK. Computational Studies of the Mechanical Stability for Single-Strand Break DNA. J Phys Chem B 2018; 122:8166-8173. [DOI: 10.1021/acs.jpcb.8b05417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Paweł Krupa
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - David J. Wales
- Department of Chemistry, Cambridge University, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Adam K. Sieradzan
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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