1
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Liu X, Chen Y, Li Y, Bai J, Zeng Z, Wang M, Dong Y, Zhou Y. STAU1-mediated CNBP mRNA degradation by LINC00665 alters stem cell characteristics in ovarian cancer. Biol Direct 2024; 19:59. [PMID: 39080743 PMCID: PMC11288052 DOI: 10.1186/s13062-024-00506-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 07/22/2024] [Indexed: 08/03/2024] Open
Abstract
BACKGROUND To investigate the role of lncRNA LINC00665 in modulating ovarian cancer stemness and its influence on treatment resistance and cancer development. METHODS We isolated ovarian cancer stem cells (OCSCs) from the COC1 cell line using a combination of chemotherapeutic agents and growth factors, and verified their stemness through western blotting and immunofluorescence for stem cell markers. Employing bioinformatics, we identified lncRNAs associated with ovarian cancer, with a focus on LINC00665 and its interaction with the CNBP mRNA. In situ hybridization, immunohistochemistry, and qPCR were utilized to examine their expression and localization, alongside functional assays to determine the effects of LINC00665 on CNBP. RESULTS LINC00665 employs its Alu elements to interact with the 3'-UTR of CNBP mRNA, targeting it for degradation. This molecular crosstalk enhances stemness by promoting the STAU1-mediated decay of CNBP mRNA, thereby modulating the Wnt and Notch signaling cascades that are pivotal for maintaining CSC characteristics and driving tumor progression. These mechanistic insights were corroborated by a series of in vitro assays and validated in vivo using tumor xenograft models. Furthermore, we established a positive correlation between elevated CNBP levels and increased disease-free survival in patients with ovarian cancer, underscoring the prognostic value of CNBP in this context. CONCLUSIONS lncRNA LINC00665 enhances stemness in ovarian cancer by mediating the degradation of CNBP mRNA, thereby identifying LINC00665 as a potential therapeutic target to counteract drug resistance and tumor recurrence associated with CSCs.
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Affiliation(s)
- Xiaofang Liu
- Department of Anus and Intestine Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China
| | - Yang Chen
- Department of General Surgery, The First Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, Shenyang, Liaoning, People's Republic of China
| | - Ying Li
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Jinling Bai
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Zhi Zeng
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Min Wang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Yaodong Dong
- Department of Otolaryngology Head and Neck Surgery, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China.
| | - Yingying Zhou
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, No. 36, Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China.
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2
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Yu M, He T, Wang Q, Cui C. Unraveling the Possibilities: Recent Progress in DNA Biosensing. BIOSENSORS 2023; 13:889. [PMID: 37754122 PMCID: PMC10526863 DOI: 10.3390/bios13090889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 08/29/2023] [Accepted: 09/09/2023] [Indexed: 09/28/2023]
Abstract
Due to the advantages of its numerous modification sites, predictable structure, high thermal stability, and excellent biocompatibility, DNA is the ideal choice as a key component of biosensors. DNA biosensors offer significant advantages over existing bioanalytical techniques, addressing limitations in sensitivity, selectivity, and limit of detection. Consequently, they have attracted significant attention from researchers worldwide. Here, we exemplify four foundational categories of functional nucleic acids: aptamers, DNAzymes, i-motifs, and G-quadruplexes, from the perspective of the structure-driven functionality in constructing DNA biosensors. Furthermore, we provide a concise overview of the design and detection mechanisms employed in these DNA biosensors. Noteworthy advantages of DNA as a sensor component, including its programmable structure, reaction predictility, exceptional specificity, excellent sensitivity, and thermal stability, are highlighted. These characteristics contribute to the efficacy and reliability of DNA biosensors. Despite their great potential, challenges remain for the successful application of DNA biosensors, spanning storage and detection conditions, as well as associated costs. To overcome these limitations, we propose potential strategies that can be implemented to solve these issues. By offering these insights, we aim to inspire subsequent researchers in related fields.
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Affiliation(s)
| | | | | | - Cheng Cui
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China; (M.Y.)
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3
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Rozza AM, Bakó I, Oláh J. Theoretical insights into water network of B-DNA duplex with Watson-Crick and Hoogsteen base pairing geometries. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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4
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Kundu N, Sharma T, Kaur S, Singh M, Kumar V, Sharma U, Jain A, Shankaraswamy J, Miyoshi D, Saxena S. Significant structural change in human c-Myc promoter G-quadruplex upon peptide binding in potassium. RSC Adv 2022; 12:7594-7604. [PMID: 35424772 PMCID: PMC8982240 DOI: 10.1039/d2ra00535b] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/02/2022] [Indexed: 01/25/2023] Open
Abstract
We selected the G-quadruplex motif located in the nuclease-hypersensitive elements (NHE) III1 region of the c-Myc promoter and for the first time performed its interaction studies with a designed peptide (QW10). Our CD results showed that the peptide bound to the c-Myc G-quadruplex and induced a significant blue shift in the positive peak of 20 nm in KCl alone or with 40wt% PEG200 or 20wt% PEG8000 in comparison to NaCl. Our Native Gel results confirmed that peptide binding destabilized the duplex and stabilized the unimolecular G-quadruplex and not binding to i-motif. UV thermal results confirmed destabilization of bimolecular structure and stabilization of unimolecular G-quadruplex. QW10 showed preferential binding towards c-MYC promoter G4 with binding constant (K b) values of the order of 0.05 ± 0.2 μM, 0.12 ± 0.1 μM and 0.05 ± 0.3 μM for complexes in K+ alone or 40wt% PEG 200 or 20wt% PEG 8000 respectively. QW10 showed preferential cytotoxicity with IC50 values of 11.10 μM and 6.44 μM after 72 and 96 hours' incubation on Human Breast Carcinoma MDA-MB 231 cells and was found to be non-toxic with Human Embryonic Kidney (HEK-1) cells. Interestingly, we observed reduction of c-Myc gene expression by 2.5 fold due to QW10 binding and stabilizing c-MYC G4. Our study for the first time provides an expanded overview of significant structural change in human c-Myc promoter G-quadruplex upon peptide binding in potassium.
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Affiliation(s)
- Nikita Kundu
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Structural Biology Lab Sector-125, Expressway Highway Noida 201313 India +91-120-4735600
| | - Taniya Sharma
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Structural Biology Lab Sector-125, Expressway Highway Noida 201313 India +91-120-4735600
| | - Sarvpreet Kaur
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Structural Biology Lab Sector-125, Expressway Highway Noida 201313 India +91-120-4735600
| | - Mamta Singh
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh Noida 201313 India
| | - Vinit Kumar
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh Noida 201313 India
| | - Uttam Sharma
- Department of Animal Sciences, Central University of Punjab Bathinda India
| | - Aklank Jain
- Department of Animal Sciences, Central University of Punjab Bathinda India
| | - Jadala Shankaraswamy
- Department of Fruit Science, College of Horticulture, Mojerla, Sri Konda Laxman Telangana State Horticultural University 509382 Telangana India
| | - Daisuke Miyoshi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe Hyogo 650-0047 Japan
| | - Sarika Saxena
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Structural Biology Lab Sector-125, Expressway Highway Noida 201313 India +91-120-4735600
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5
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Debbarma S, Acharya PC. Targeting G-Quadruplex Dna For Cancer Chemotherapy. Curr Drug Discov Technol 2022; 19:e140222201110. [PMID: 35156574 DOI: 10.2174/1570163819666220214115408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/24/2021] [Accepted: 12/03/2021] [Indexed: 11/22/2022]
Abstract
The self-association of DNA formed by Hoogsteen hydrogen bonding comprises several layers of four guanine or G-tetrads or G4s. The distinct feature of G4s, such as the G-tetrads and loops, qualify structure-selective recognition by small molecules and various ligands and can act as potential anticancer therapeutic molecules. The G4 selective-ligands, can influence gene expression by targeting a nucleic acid structure rather than sequence. Telomere G4 can be targeted for cancer treatment by small molecules inhibiting the telomerase activity whereas c-MYC is capable of controlling transcription, can be targeted to influence transcription. The k-RAS is one of the most frequently encountered oncogenic driver mutations in pancreatic, colorectal, and lung cancers. The k-RAS oncogene plays important role in acquiring and increasing the drug resistance and can also be directly targeted by small molecules to combat k-RAS mutant tumors. Modular G4 ligands with different functional groups, side chains and rotatable bonds as well as conformation affect the binding affinity/selectivity in cancer chemotherapeutic interventions. These modular G4 ligands act by targeting the diversity of G4 loops and groves and assists to develop more drug-like compounds with selectivity. In this review, we present the recent research on synthetic G4 DNA-interacting ligands as an approach toward the discovery of target specific anticancer chemotherapeutic agents.
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Affiliation(s)
- Sumanta Debbarma
- Department of Pharmacy, Tripura University, Suryamaninagar-799022, India
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6
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Trigiante G, Blanes Ruiz N, Cerase A. Emerging Roles of Repetitive and Repeat-Containing RNA in Nuclear and Chromatin Organization and Gene Expression. Front Cell Dev Biol 2021; 9:735527. [PMID: 34722514 PMCID: PMC8552494 DOI: 10.3389/fcell.2021.735527] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/09/2021] [Indexed: 12/14/2022] Open
Abstract
Genomic repeats have been intensely studied as regulatory elements controlling gene transcription, splicing and genome architecture. Our understanding of the role of the repetitive RNA such as the RNA coming from genomic repeats, or repetitive sequences embedded in mRNA/lncRNAs, in nuclear and cellular functions is instead still limited. In this review we discuss evidence supporting the multifaceted roles of repetitive RNA and RNA binding proteins in nuclear organization, gene regulation, and in the formation of dynamic membrane-less aggregates. We hope that our review will further stimulate research in the consolidating field of repetitive RNA biology.
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Affiliation(s)
| | | | - Andrea Cerase
- Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Blizard Institute, Queen Mary University of London, London, United Kingdom
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7
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How the stability, reactivity and optical response of the protonated base pairs differ with other biologically important adenine–thymine pairs: a DFT and TD-DFT approach. CHEMICAL PAPERS 2021. [DOI: 10.1007/s11696-020-01474-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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TOP mRNPs: Molecular Mechanisms and Principles of Regulation. Biomolecules 2020; 10:biom10070969. [PMID: 32605040 PMCID: PMC7407576 DOI: 10.3390/biom10070969] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/20/2020] [Accepted: 06/23/2020] [Indexed: 02/08/2023] Open
Abstract
The cellular response to changes in the surrounding environment and to stress requires the coregulation of gene networks aiming to conserve energy and resources. This is often achieved by downregulating protein synthesis. The 5’ Terminal OligoPyrimidine (5’ TOP) motif-containing mRNAs, which encode proteins that are essential for protein synthesis, are the primary targets of translational control under stress. The TOP motif is a cis-regulatory RNA element that begins directly after the m7G cap structure and contains the hallmark invariant 5’-cytidine followed by an uninterrupted tract of 4–15 pyrimidines. Regulation of translation via the TOP motif coordinates global protein synthesis with simultaneous co-expression of the protein components required for ribosome biogenesis. In this review, we discuss architecture of TOP mRNA-containing ribonucleoprotein complexes, the principles of their assembly, and the modes of regulation of TOP mRNA translation.
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9
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Drevet JR, Aitken RJ. Oxidation of Sperm Nucleus in Mammals: A Physiological Necessity to Some Extent with Adverse Impacts on Oocyte and Offspring. Antioxidants (Basel) 2020; 9:E95. [PMID: 31979208 PMCID: PMC7070651 DOI: 10.3390/antiox9020095] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/19/2020] [Accepted: 01/21/2020] [Indexed: 12/15/2022] Open
Abstract
Sperm cells have long been known to be good producers of reactive oxygen species, while they are also known to be particularly sensitive to oxidative damage affecting their structures and functions. As with all organic cellular components, sperm nuclear components and, in particular, nucleic acids undergo oxidative alterations that have recently been shown to be commonly encountered in clinical practice. This review will attempt to provide an overview of this situation. After a brief coverage of the biological reasons why the sperm nucleus and associated DNA are sensitive to oxidative damage, a summary of the most recent results concerning the oxidation of sperm DNA in animal and human models will be presented. The study will then attempt to cover the possible consequences of sperm nuclear oxidation on male fertility and beyond.
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Affiliation(s)
- Joël R. Drevet
- Faculty of Medicine, GReD Institute, INSERM U1103—CNRS UMR6293—Université Clermont Auvergne, CRBC building, 28 place Henri Dunant, 63001 Clermont-Ferrand, France
| | - Robert John Aitken
- School of Environmental and Life Sciences, Priority Research Centre for Reproductive Sciences, The University of Newcastle, Callaghan, Newcastle 2308, Australia;
- Faculty of Health and Medicine, The University of Newcastle, Callaghan, Newcastle 2308, Australia
- Medical Genetics, Hunter Medical Research Institute, New Lambton Heights, 13 2305 Newcastle, Australia
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10
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Mukherjee AK, Sharma S, Bagri S, Kutum R, Kumar P, Hussain A, Singh P, Saha D, Kar A, Dash D, Chowdhury S. Telomere repeat-binding factor 2 binds extensively to extra-telomeric G-quadruplexes and regulates the epigenetic status of several gene promoters. J Biol Chem 2019; 294:17709-17722. [PMID: 31575660 PMCID: PMC6879327 DOI: 10.1074/jbc.ra119.008687] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 09/18/2019] [Indexed: 12/22/2022] Open
Abstract
The role of the telomere repeat-binding factor 2 (TRF2) in telomere maintenance is well-established. However, recent findings suggest that TRF2 also functions outside telomeres, but relatively little is known about this function. Herein, using genome-wide ChIP-Seq assays of TRF2-bound chromatin from HT1080 fibrosarcoma cells, we identified thousands of TRF2-binding sites within the extra-telomeric genome. In light of this observation, we asked how TRF2 occupancy is organized within the genome. Interestingly, we found that extra-telomeric TRF2 sites throughout the genome are enriched in potential G-quadruplex-forming DNA sequences. Furthermore, we validated TRF2 occupancy at several promoter G-quadruplex motifs, which did adopt quadruplex forms in solution. TRF2 binding altered expression and the epigenetic state of several target promoters, indicated by histone modifications resulting in transcriptional repression of eight of nine genes investigated here. Furthermore, TRF2 occupancy and target gene expression were also sensitive to the well-known intracellular G-quadruplex-binding ligand 360A. Together, these results reveal an extensive genome-wide association of TRF2 outside telomeres and that it regulates gene expression in a G-quadruplex-dependent fashion.
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Affiliation(s)
- Ananda Kishore Mukherjee
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Shalu Sharma
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Sulochana Bagri
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Rintu Kutum
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,CSIR Ayurgenomics Unit-TRISUTRA, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Pankaj Kumar
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Asgar Hussain
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Prateek Singh
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Dhurjhoti Saha
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Anirban Kar
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Debasis Dash
- Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,CSIR Ayurgenomics Unit-TRISUTRA, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India .,Academy of Scientific and Innovative Research (AcSIR), Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India.,G.N.R. Knowledge Centre for Genome Informatics, Council of Scientific and Industrial Research (CSIR)-Institute of Genomics and Integrative Biology (IGIB), Mathura Road, New Delhi 110025, India
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11
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Non-duplex G-Quadruplex Structures Emerge as Mediators of Epigenetic Modifications. Trends Genet 2018; 35:129-144. [PMID: 30527765 DOI: 10.1016/j.tig.2018.11.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/10/2018] [Accepted: 11/02/2018] [Indexed: 12/16/2022]
Abstract
The role of non-duplex DNA, the guanine-quadruplex structure in particular, is becoming widely appreciated. Increasing evidence in the last decade implicates quadruplexes in important processes such as transcription and replication. Interestingly, more recent work suggests roles for quadruplexes, in association with quadruplex-interacting proteins, in epigenetics through both DNA and histone modifications. Here, we review the effect of the quadruplex structure on post-replication epigenetic memory and quadruplex-induced promoter DNA/histone modifications. Furthermore, we highlight the epigenetic state of the telomerase promoter where quadruplexes could play a key regulatory role. Finally, we discuss the possibility that DNA structures such as quadruplexes, within a largely duplex DNA background, could act as molecular anchors for locally induced epigenetic modifications.
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12
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Ghoshdastidar D, Bansal M. Dynamics of physiologically relevant noncanonical DNA structures: an overview from experimental and theoretical studies. Brief Funct Genomics 2018; 18:192-204. [DOI: 10.1093/bfgp/ely026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 06/23/2018] [Accepted: 07/09/2018] [Indexed: 12/23/2022] Open
Abstract
Abstract
DNA is a complex molecule with phenomenal inherent plasticity and the ability to form different hydrogen bonding patterns of varying stabilities. These properties enable DNA to attain a variety of structural and conformational polymorphic forms. Structurally, DNA can exist in single-stranded form or as higher-order structures, which include the canonical double helix as well as the noncanonical duplex, triplex and quadruplex species. Each of these structural forms in turn encompasses an ensemble of dynamically heterogeneous conformers depending on the sequence composition and environmental context. In vivo, the widely populated canonical B-DNA attains these noncanonical polymorphs during important cellular processes. While several investigations have focused on the structure of these noncanonical DNA, studying their dynamics has remained nontrivial. Here, we outline findings from some recent advanced experimental and molecular simulation techniques that have significantly contributed toward understanding the complex dynamics of physiologically relevant noncanonical forms of DNA.
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Affiliation(s)
| | - Manju Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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13
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Baek IJ, Moss DS, Lustig AJ. The mre11 A470 alleles influence the hereditability and the segregation of telosomes in Saccharomyces cerevisiae. PLoS One 2017; 12:e0183549. [PMID: 28886051 PMCID: PMC5590830 DOI: 10.1371/journal.pone.0183549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 08/07/2017] [Indexed: 11/18/2022] Open
Abstract
Telomeres, the nucleoprotein complexes at the termini of linear chromosomes, are essential for the processes of end replication, end protection, and chromatin segregation. The Mre11 complex is involved in multiple cellular roles in DNA repair and structure in the regulation and function of telomere size homeostasis. In this study, we characterize yeast telomere chromatin structure, phenotypic heritability, and chromatin segregation in both wild-type [MRE11] and A470 motif alleles. MRE11 strains confer a telomere size of 300 base pairs of G+T irregular simple sequence repeats. This DNA and a portion of subtelomeric DNA is embedded in a telosome: a MNase-resistant non-nucleosomal particle. Chromatin immunoprecipitation shows a three to four-fold lower occupancy of Mre11A470T proteins than wild-type proteins in telosomes. Telosomes containing the Mre11A470T protein confer a greater resistance to MNase digestion than wild-type telosomes. The integration of a wild-type MRE11 allele into an ectopic locus in the genome of an mre11A470T mutant and the introduction of an mre11A470T allele at an ectopic site in a wild-type strain lead to unexpectedly differing results. In each case, the replicated sister chromatids inherit telosomes containing only the protein encoded by the genomic mre11 locus, even in the presence of protein encoded by the opposing ectopic allele. We hypothesize that the telosome segregates by a conservative mechanism. These data support a mechanism for the linkage between sister chromatid replication and maintenance of either identical mutant or identical wild-type telosomes after replication of sister chromatids. These data suggest the presence of an active mechanism for chromatin segregation in yeast.
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Affiliation(s)
- In-Joon Baek
- Department of Biochemistry and Molecular Biology, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - Daniel S. Moss
- Department of Biochemistry and Molecular Biology, Tulane University Medical Center, New Orleans, Louisiana, United States of America
| | - Arthur J. Lustig
- Department of Biochemistry and Molecular Biology, Tulane University Medical Center, New Orleans, Louisiana, United States of America
- * E-mail:
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14
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Kshirsagar R, Khan K, Joshi MV, Hosur RV, Muniyappa K. Probing the Potential Role of Non-B DNA Structures at Yeast Meiosis-Specific DNA Double-Strand Breaks. Biophys J 2017; 112:2056-2074. [PMID: 28538144 DOI: 10.1016/j.bpj.2017.04.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/13/2017] [Accepted: 04/19/2017] [Indexed: 12/29/2022] Open
Abstract
A plethora of evidence suggests that different types of DNA quadruplexes are widely present in the genome of all organisms. The existence of a growing number of proteins that selectively bind and/or process these structures underscores their biological relevance. Moreover, G-quadruplex DNA has been implicated in the alignment of four sister chromatids by forming parallel guanine quadruplexes during meiosis; however, the underlying mechanism is not well defined. Here we show that a G/C-rich motif associated with a meiosis-specific DNA double-strand break (DSB) in Saccharomyces cerevisiae folds into G-quadruplex, and the C-rich sequence complementary to the G-rich sequence forms an i-motif. The presence of G-quadruplex or i-motif structures upstream of the green fluorescent protein-coding sequence markedly reduces the levels of gfp mRNA expression in S. cerevisiae cells, with a concomitant decrease in green fluorescent protein abundance, and blocks primer extension by DNA polymerase, thereby demonstrating the functional significance of these structures. Surprisingly, although S. cerevisiae Hop1, a component of synaptonemal complex axial/lateral elements, exhibits strong affinity to G-quadruplex DNA, it displays a much weaker affinity for the i-motif structure. However, the Hop1 C-terminal but not the N-terminal domain possesses strong i-motif binding activity, implying that the C-terminal domain has a distinct substrate specificity. Additionally, we found that Hop1 promotes intermolecular pairing between G/C-rich DNA segments associated with a meiosis-specific DSB site. Our results support the idea that the G/C-rich motifs associated with meiosis-specific DSBs fold into intramolecular G-quadruplex and i-motif structures, both in vitro and in vivo, thus revealing an important link between non-B form DNA structures and Hop1 in meiotic chromosome synapsis and recombination.
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Affiliation(s)
- Rucha Kshirsagar
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Krishnendu Khan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Mamata V Joshi
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Ramakrishna V Hosur
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, India.
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15
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Kaulage M, Maji B, Bhat J, Iwasaki Y, Chatterjee S, Bhattacharya S, Muniyappa K. Discovery and Structural Characterization of G-quadruplex DNA in Human Acetyl-CoA Carboxylase Gene Promoters: Its Role in Transcriptional Regulation and as a Therapeutic Target for Human Disease. J Med Chem 2016; 59:5035-50. [PMID: 27058681 DOI: 10.1021/acs.jmedchem.6b00453] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Accumulating evidence suggests that G-quadruplexes play vital roles in gene expression, DNA replication, and recombination. Three distinct promoters (PI, PII, and PIII) regulate human acetyl-CoA carboxylase 1 (ACC1) gene expression. In this study, we asked whether the G-rich sequences within the human ACC1 (PI and PII) promoters can form G-quadruplex structures and regulate normal DNA transactions. Using multiple complementary methods, we show that G-rich sequences of PI and PII promoters form intramolecular G-quadruplex structures and then establish unambiguously the topologies of these structures. Importantly, G-quadruplex formation in ACC1 gene promoter region blocks DNA replication and suppresses transcription, and this effect was further augmented by G-quadruplex stabilizing ligands. Altogether, these results are consistent with the notion that G-quadruplex structures exist within the human ACC1 gene promoter region, whose activity can be suppressed by G-quadruplex stabilizing ligands, thereby revealing a novel regulatory mechanism of ACC1 gene expression and as a possible therapeutic target.
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Affiliation(s)
| | | | - Jyotsna Bhat
- Department of Biophysics, Bose Institute , Kolkata 700054, India
| | - Yasumasa Iwasaki
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University , Nankoku 780-8520, Japan
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16
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O'Sullivan DM, Laver T, Temisak S, Redshaw N, Harris KA, Foy CA, Studholme DJ, Huggett JF. Assessing the accuracy of quantitative molecular microbial profiling. Int J Mol Sci 2014; 15:21476-91. [PMID: 25421243 PMCID: PMC4264237 DOI: 10.3390/ijms151121476] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 11/11/2014] [Accepted: 11/14/2014] [Indexed: 01/04/2023] Open
Abstract
The application of high-throughput sequencing in profiling microbial communities is providing an unprecedented ability to investigate microbiomes. Such studies typically apply one of two methods: amplicon sequencing using PCR to target a conserved orthologous sequence (typically the 16S ribosomal RNA gene) or whole (meta)genome sequencing (WGS). Both methods have been used to catalog the microbial taxa present in a sample and quantify their respective abundances. However, a comparison of the inherent precision or bias of the different sequencing approaches has not been performed. We previously developed a metagenomic control material (MCM) to investigate error when performing different sequencing strategies. Amplicon sequencing using four different primer strategies and two 16S rRNA regions was examined (Roche 454 Junior) and compared to WGS (Illumina HiSeq). All sequencing methods generally performed comparably and in good agreement with organism specific digital PCR (dPCR); WGS notably demonstrated very high precision. Where discrepancies between relative abundances occurred they tended to differ by less than twofold. Our findings suggest that when alternative sequencing approaches are used for microbial molecular profiling they can perform with good reproducibility, but care should be taken when comparing small differences between distinct methods. This work provides a foundation for future work comparing relative differences between samples and the impact of extraction methods. We also highlight the value of control materials when conducting microbial profiling studies to benchmark methods and set appropriate thresholds.
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Affiliation(s)
| | - Thomas Laver
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
| | - Sasithon Temisak
- Molecular Biology, LGC Ltd., Queens Road, Teddington TW11 0LY, UK.
| | - Nicholas Redshaw
- Molecular Biology, LGC Ltd., Queens Road, Teddington TW11 0LY, UK.
| | - Kathryn A Harris
- Department of Microbiology, Virology and Infection Control, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London WC1N 3JH, UK.
| | - Carole A Foy
- Molecular Biology, LGC Ltd., Queens Road, Teddington TW11 0LY, UK.
| | - David J Studholme
- Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK.
| | - Jim F Huggett
- Molecular Biology, LGC Ltd., Queens Road, Teddington TW11 0LY, UK.
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17
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Brovarets' OO. [Under what conditions does G.C Watson-Crick DNA base pair acquire all four configurations characteristic for A.T Watson-Crick DNA base pair?]. UKRAINIAN BIOCHEMICAL JOURNAL 2013; 85:98-103. [PMID: 24319979 DOI: 10.15407/ubj85.04.098] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
At the MP2/6-311++G(2df,pd)//B3LYP/6-311++G(d,p) level of theory it was established for the first time, that the Löwdin's G*.C* DNA base pair formed by the mutagenic tautomers can acquire, as the A-T Watson-Crick DNA base pair, four biologically important configurations, namely: Watson-Crick, reverse Watson-Crick, Hoogsteen and reverse Hoogsteen. This fact demonstrates rather unexpected role of the tautomerisation of the one of the Watson-Crick DNA base pairs, in particular, via double proton transfer: exactly the G.C-->G*.C* tautomerisation allows to overcome steric hindrances for the implementation of the above mentioned configurations. Geometric, electron-topological and energetic properties of the H-bonds that stabilise the studied pairs, as well as the energetic characteristics of the latters are presented.
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18
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Brovarets’ OO, Yurenko YP, Hovorun DM. Intermolecular CH···O/N H-bonds in the biologically important pairs of natural nucleobases: a thorough quantum-chemical study. J Biomol Struct Dyn 2013; 32:993-1022. [PMID: 23730732 DOI: 10.1080/07391102.2013.799439] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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19
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Mendez MA, Szalai VA. Synapsable quadruplex-mediated fibers. NANOSCALE RESEARCH LETTERS 2013; 8:210. [PMID: 23641903 PMCID: PMC3655031 DOI: 10.1186/1556-276x-8-210] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/20/2013] [Indexed: 06/02/2023]
Abstract
We have fabricated a DNA-based nanofiber created by self-assembly of guanine quadruplex (Hoogsteen base pairing) and double-stranded DNA (Watson-Crick base pairing). When duplexes containing a long stretch of contiguous guanines and single-stranded overhangs are incubated in potassium-containing buffer, the preformed duplexes create high molecular weight species that contain quadruplexes. In addition to observation of these larger species by gel electrophoresis, solutions were analyzed by atomic force microscopy to reveal nanofibers. Analysis of the atomic force microscopy images indicates that fibers form with lengths ranging from 250 to 2,000 nm and heights from 0.45 to 4.0 nm. This work is a first step toward the creation of new structurally heterogeneous (quadruplex/duplex), yet controllable, DNA-based materials exhibiting novel properties suitable for a diverse array of nanotechnology applications.
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Affiliation(s)
- Miguel Angel Mendez
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Drive, Baltimore, MD, 21250, USA
- Universidad San Francisco de Quito, Vía Interoceánica Km 2 1/2, Cumbayá, Quito, 17-1200-84, Ecuador
| | - Veronika A Szalai
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Drive, Baltimore, MD, 21250, USA
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899-6204, USA
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20
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Lexa M, Martínek T, Burgetová I, Kopeček D, Brázdová M. A dynamic programming algorithm for identification of triplex-forming sequences. ACTA ACUST UNITED AC 2011; 27:2510-7. [PMID: 21791534 DOI: 10.1093/bioinformatics/btr439] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
MOTIVATION Current methods for identification of potential triplex-forming sequences in genomes and similar sequence sets rely primarily on detecting homopurine and homopyrimidine tracts. Procedures capable of detecting sequences supporting imperfect, but structurally feasible intramolecular triplex structures are needed for better sequence analysis. RESULTS We modified an algorithm for detection of approximate palindromes, so as to account for the special nature of triplex DNA structures. From available literature, we conclude that approximate triplexes tolerate two classes of errors. One, analogical to mismatches in duplex DNA, involves nucleotides in triplets that do not readily form Hoogsteen bonds. The other class involves geometrically incompatible neighboring triplets hindering proper alignment of strands for optimal hydrogen bonding and stacking. We tested the statistical properties of the algorithm, as well as its correctness when confronted with known triplex sequences. The proposed algorithm satisfactorily detects sequences with intramolecular triplex-forming potential. Its complexity is directly comparable to palindrome searching. AVAILABILITY Our implementation of the algorithm is available at http://www.fi.muni.cz/lexa/triplex as source code and a web-based search tool. The source code compiles into a library providing searching capability to other programs, as well as into a stand-alone command-line application based on this library. CONTACT lexa@fi.muni.cz SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Matej Lexa
- Department of Information Technology, Faculty of Informatics, Masaryk University, 60200 Brno, Czech Republic.
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21
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Calcaterra NB, Armas P, Weiner AMJ, Borgognone M. CNBP: a multifunctional nucleic acid chaperone involved in cell death and proliferation control. IUBMB Life 2011; 62:707-14. [PMID: 20960530 DOI: 10.1002/iub.379] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cellular nucleic acid binding protein (CNBP) has been implicated in vertebrate craniofacial development and in myotonic dystrophy type 2 (DM2) and sporadic inclusion body myositis (sIBM) human diseases. In these seemingly unrelated biological processes, CNBP appears to be involved in controlling cell death and proliferation rates. Low levels of CNBP may reduce rate of global protein synthesis, thereby reducing proliferation and increasing apoptosis. Conversely, CNBP might affect transcription of genes required for cell proliferation. Experimental evidences gathered so far make it difficult to ascertain or rule out any of these possibilities. Moreover, both possibilities may not be mutually exclusive. CNBP is a small and strikingly conserved single-stranded nucleic acid binding protein that is able to bind DNA as well as RNA. CNBP has a broad spectrum of targets, ranging from regulatory sites in gene promoters to translational regulatory elements in mRNA untranslated regions. Biochemical experiments have recently shed light on the possible mechanism of action for CNBP, which may act as a nucleic acid chaperone catalyzing the rearrangement of G-rich nucleic acid secondary structures likely relevant for transcriptional and/or translational gene regulation. This review focuses on the involvement of CNBP in vertebrate craniofacial development and human DM2 and sIBM diseases, as well as on the biochemical and structural features of CNBP and its cellular and molecular mechanism of action.
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Affiliation(s)
- Nora B Calcaterra
- Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas- Área Biología General, Dpto. de Ciencias Biológicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK-Rosario, Argentina.
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22
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Nikolova EN, Kim E, Wise AA, O’Brien PJ, Andricioaei I, Al-Hashimi HM. Transient Hoogsteen base pairs in canonical duplex DNA. Nature 2011; 470:498-502. [PMID: 21270796 PMCID: PMC3074620 DOI: 10.1038/nature09775] [Citation(s) in RCA: 266] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2010] [Accepted: 01/05/2011] [Indexed: 12/17/2022]
Abstract
Sequence-directed variations in the canonical DNA double helix structure that retain Watson-Crick base-pairing have important roles in DNA recognition, topology and nucleosome positioning. By using nuclear magnetic resonance relaxation dispersion spectroscopy in concert with steered molecular dynamics simulations, we have observed transient sequence-specific excursions away from Watson-Crick base-pairing at CA and TA steps inside canonical duplex DNA towards low-populated and short-lived A•T and G•C Hoogsteen base pairs. The observation of Hoogsteen base pairs in DNA duplexes specifically bound to transcription factors and in damaged DNA sites implies that the DNA double helix intrinsically codes for excited state Hoogsteen base pairs as a means of expanding its structural complexity beyond that which can be achieved based on Watson-Crick base-pairing. The methods presented here provide a new route for characterizing transient low-populated nucleic acid structures, which we predict will be abundant in the genome and constitute a second transient layer of the genetic code.
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Affiliation(s)
- Evgenia N. Nikolova
- Department of Chemistry & Biophysics, University of Michigan, 930 North University Avenue Ann Arbor, MI 48109-1055, USA, Tel: 734-615-3361, Fax: 734-647-4865
| | - Eunae Kim
- Department of Chemistry, University of California, Natural Sciences 2, Irvine, California 92697, Tel: 949-824-3569, Fax: 949-824-9920
| | - Abigail A. Wise
- Department of Chemistry & Biophysics, University of Michigan, 930 North University Avenue Ann Arbor, MI 48109-1055, USA, Tel: 734-615-3361, Fax: 734-647-4865
| | - Patrick J. O’Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Ioan Andricioaei
- Department of Chemistry, University of California, Natural Sciences 2, Irvine, California 92697, Tel: 949-824-3569, Fax: 949-824-9920
| | - Hashim M. Al-Hashimi
- Department of Chemistry & Biophysics, University of Michigan, 930 North University Avenue Ann Arbor, MI 48109-1055, USA, Tel: 734-615-3361, Fax: 734-647-4865
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23
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González V, Hurley LH. The C-terminus of nucleolin promotes the formation of the c-MYC G-quadruplex and inhibits c-MYC promoter activity. Biochemistry 2010; 49:9706-14. [PMID: 20932061 PMCID: PMC2976822 DOI: 10.1021/bi100509s] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nucleolin, the most abundant nucleolar phosphoprotein of eukaryotic cells, is known primarily for its role in ribosome biogenesis and cell proliferation. It is, however, a multifunctional protein that, depending on the cellular context, can drive either cell proliferation or apoptosis. Our laboratory recently demonstrated that nucleolin can function as a repressor of c-MYC transcription by binding to and stabilizing the formation of a G-quadruplex structure in a region of the c-MYC promoter responsible for controlling 85-90% of c-MYC's transcriptional activity. In this study, we investigate the structural elements of nucleolin that are required for c-MYC repression. The effect of nucleolin deletion mutants on the formation and stability of the c-MYC G-quadruplex, as well as c-MYC transcriptional activity, was assessed by circular dichroism spectropolarimetry, thermal stability, and in vitro transcription. Here we report that nucleolin's RNA binding domains 3 and 4, as well as the arginine-glycine-glycine (RGG) domain, are required to repress c-MYC transcription.
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Affiliation(s)
- Verónica González
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721
| | - Laurence H. Hurley
- College of Pharmacy, Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona 85721
- University of Arizona, BIO5 Institute, Tucson, Arizona 85721
- University of Arizona, Arizona Cancer Center, Tucson, Arizona 85724
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24
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Liu JQ, Chen CY, Xue Y, Hao YH, Tan Z. G-Quadruplex Hinders Translocation of BLM Helicase on DNA: A Real-Time Fluorescence Spectroscopic Unwinding Study and Comparison with Duplex Substrates. J Am Chem Soc 2010; 132:10521-7. [DOI: 10.1021/ja1038165] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jia-quan Liu
- Laboratory of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, and State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Chang-yue Chen
- Laboratory of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, and State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Yong Xue
- Laboratory of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, and State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Yu-hua Hao
- Laboratory of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, and State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Zheng Tan
- Laboratory of Biochemistry and Biophysics, College of Life Sciences, Wuhan University, Wuhan 430072, P. R. China, and State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
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25
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Concise access to N9-mono-, N2-mono- and N2,N9-di-substituted guanines via efficient Mitsunobu reactions. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.03.118] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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26
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Crystal structure of an intermolecular 2:1 complex between adenine and thymine. Evidence for both Hoogsteen and 'quasi-Watson-Crick' interactions. Bioorg Med Chem Lett 2010; 20:3530-3. [PMID: 20493694 DOI: 10.1016/j.bmcl.2010.04.131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 04/16/2010] [Accepted: 04/28/2010] [Indexed: 11/23/2022]
Abstract
The titled complex, obtained by co-crystallization (EtOH/25 degrees C), is apparently the only known complex of the free bases. Its crystal structure, as determined by X-ray diffraction at both 90 K and 313 K, showed that one A-T pair involves a Hoogsteen interaction, and the other a Watson-Crick interaction but only with respect to the adenine unit. The absence of a clear-cut Watson-Crick base pair raises intriguing questions about the basis of the DNA double helix.
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27
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Arora A, Kumar N, Agarwal T, Maiti S. Retraction: Human telomeric G-quadruplex: targeting with small molecules. FEBS J 2009; 277:1345. [DOI: 10.1111/j.1742-4658.2009.07461.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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28
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Kang HJ, Park HJ. Novel molecular mechanism for actinomycin D activity as an oncogenic promoter G-quadruplex binder. Biochemistry 2009; 48:7392-8. [PMID: 19496619 DOI: 10.1021/bi9006836] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Actinomycin D (ActD) is a natural antibiotic that inhibits the transcription of genes by interacting with a GC-rich duplex, a single-stranded or hairpin form of DNA, and then interfering with the action of RNA polymerase. In this study, we identified a novel molecular mechanism of anticancer activity of ActD as an oncogenic c-Myc promoter G-quadruplex binder. ActD selectively inhibits the elongation of oligonucleotides containing c-Myc promoter G-quadruplex sequence in PCR-stop assays. UV-vis spectroscopic and circular dichroism studies suggest that ActD interacts with c-Myc promoter G-quadruplex via a surface end stacking interaction, inducing a mixed-type conformation of the G-quadruplex. ActD selectively inhibits the cellular growth and synthesis of c-Myc mRNA in Ramos cells having the NHEIII(1) region in the translocated c-Myc gene. In addition, the results of promoter assays using two kinds of NHEIII(1) region mutants and wild-type constructs strongly support the idea that binding of ActD with G-quadruplex formed in the promoter region results in the reporter gene being turned off. Our study reveals a novel mechanism underlying the anticancer activity of ActD, whereby ActD interacts with oncogenic promoter G-quadruplex DNA to repress gene expression.
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Affiliation(s)
- Hyun-Jin Kang
- College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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29
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Nikan M, Sherman JC. Cation-Complexation Behavior of Template-Assembled Synthetic G-Quartets. J Org Chem 2009; 74:5211-8. [DOI: 10.1021/jo9001245] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mehran Nikan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
| | - John C. Sherman
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
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30
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Kumar N, Basundra R, Maiti S. Elevated polyamines induce c-MYC overexpression by perturbing quadruplex-WC duplex equilibrium. Nucleic Acids Res 2009; 37:3321-31. [PMID: 19324889 PMCID: PMC2691834 DOI: 10.1093/nar/gkp196] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The biological role of quadruplexes and polyamines has been independently associated with cancer. However, quadruplex-polyamine mediated transcriptional regulation remain unaddressed. Herein, using c-MYC quadruplex model, we have attempted to understand quadruplex–polyamine interaction and its role in transcriptional regulation. We initially employed biophysical approach involving CD, UV and FRET to understand the role of polyamines (spermidine and spermine) on conformation, stability, molecular recognition of quadruplex and to investigate the effect of polyamines on quadruplex–Watson Crick duplex transition. Our study demonstrates that polyamines affect the c-MYC quadruplex conformation, perturb its recognition properties and delays duplex formation. The relative free energy difference (ΔΔG°) between the duplex and quadruplex structure indicate that polyamines stabilize and favor c-MYC quadruplex over duplex. Further, we investigated the influence of polyamine mediated perturbation of this equilibrium on c-MYC expression. Our results suggest that polyamines induce structural transition of c-MYC quadruplex to a transcriptionally active motif with distinctive molecular recognition property, which drives c-MYC expression. These findings may allow exploiting quadruplex–polyamines interaction for developing antiproliferative strategies to combat aberrant gene expression.
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Affiliation(s)
| | | | - Souvik Maiti
- *To whom correspondence should be addressed. Tel: +91 11 2766 6156; Fax: +91 11 2766 7471; ,
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31
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Kumar N, Patowary A, Sivasubbu S, Petersen M, Maiti S. Silencing c-MYC expression by targeting quadruplex in P1 promoter using locked nucleic acid trap. Biochemistry 2009; 47:13179-88. [PMID: 19053274 DOI: 10.1021/bi801064j] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nuclease hypersensitive element of P1 promoter in c-MYC gene harbors a potential of unusual structure called quadruplex, which is involved in molecular recognition and function. This Hoogsteen bonded structure is in dynamic equilibrium with the usual Watson-Crick duplex structure, and these competing secondary structures undergo interconversion for execution of their respective biological roles. Herein, we investigate the sensitivity of the c-MYC quadruplex-duplex equilibrium by employing a locked nucleic acid (LNA) modified complementary strand as a pharmacological agent. Our biophysical experiments indicate that the c-MYC quadruplex under physiological conditions is stable and dominates the quadruplex-WC duplex equilibrium in both sodium and potassium buffers. This equilibrium is perturbed upon introducing the LNA modified complementary strand, which demonstrates efficient invasion of stable c-MYC quadruplex and duplex formation in contrast to the unmodified complementary strand. Our data indicate that LNA modifications confer increased thermodynamic stability to the duplex and thus favor the predominance of the duplex population over that of the quadruplex. Further, we demonstrate that this perturbation of equilibrium by a pharmacological agent results in altered gene expression. Our in vivo experiment performed using the LNA modified complementary strand suggests the influence of the quadruplex-duplex structural switch in the modulation of gene expression. We believe that this exploratory approach utilizing the selectivity and specificity of Watson-Crick base pairing of LNA bases would allow the modulation of quadruplex regulated gene expression.
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Affiliation(s)
- Niti Kumar
- Institute of Genomics and Integrative Biology, CSIR, Mall Road, Delhi 110007, India
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32
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Kumar N, Sahoo B, Varun KAS, Maiti S, Maiti S. Effect of loop length variation on quadruplex-Watson Crick duplex competition. Nucleic Acids Res 2008; 36:4433-42. [PMID: 18599514 PMCID: PMC2490738 DOI: 10.1093/nar/gkn402] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
The effect of loop length on quadruplex stability has been studied when the G-rich strand is present along with its complementary C-rich strand, thereby resulting in competition between quadruplex and duplex structures. Using model sequences with loop lengths varying from T to T5, we carried out extensive FRET to discover the influence of loop length on the quadruplex-Watson Crick duplex competition. The binding data show an increase in the binding affinity of quadruplexes towards their complementary strands upon increasing the loop length. Our kinetic data reveal that unfolding of the quadruplex in presence of a complementary strand involves a contribution from a predominant slow and a small population of fast opening conformer. The contribution from the fast opening conformer increases upon increasing the loop length leading to faster duplex formation. FCS data show an increase in the interconversion between the quadruplex conformers in presence of the complementary strand, which shifts the equilibrium towards the fast opening conformer with an increase in loop length. The relative free-energy difference (ΔΔG°) between the duplex and quadruplex indicates that an increase in loop length favors duplex formation and out competes the quadruplex.
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Affiliation(s)
- Niti Kumar
- Proteomics and Structural Biology Unit, Institute of Genomics and Integrative Biology, CSIR, Mall Road, Delhi 110 007, India
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Pous J, Urpí L, Subirana JA, Gouyette C, Navaza J, Campos JL. Stabilization by extra-helical thymines of a DNA duplex with Hoogsteen base pairs. J Am Chem Soc 2008; 130:6755-60. [PMID: 18447354 DOI: 10.1021/ja078022+] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present the crystal structure of the DNA duplex formed by d(ATATATCT). The crystals contain seven stacked antiparallel duplexes in the asymmetric unit with A.T Hoogsteen base pairs. The terminal CT sequences bend over so that the thymines enter the minor groove and form a hydrogen bond with thymine 2 of the complementary strand in the Hoogsteen duplex. Cytosines occupy extra-helical positions; they contribute to the crystal lattice through various kinds of interactions, including a unique CAA triplet. The presence of thymine in the minor groove apparently contributes to the stability of the DNA duplex in the Hoogsteen conformation. These observations open the way toward finding under what conditions the Hoogsteen duplex may be stabilized in vivo. The present crystal structure also confirms the tendency of A.T-rich oligonucleotides to crystallize as long helical stacks of duplexes.
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Affiliation(s)
- Joan Pous
- Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, E-08028 Barcelona, Spain
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Franceschin M, Lombardo CM, Pascucci E, D’Ambrosio D, Micheli E, Bianco A, Ortaggi G, Savino M. The number and distances of positive charges of polyamine side chains in a series of perylene diimides significantly influence their ability to induce G-quadruplex structures and inhibit human telomerase. Bioorg Med Chem 2008; 16:2292-304. [DOI: 10.1016/j.bmc.2007.11.065] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 11/16/2007] [Accepted: 11/23/2007] [Indexed: 11/30/2022]
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Mather BD, Baker MB, Beyer FL, Berg MAG, Green MD, Long TE. Supramolecular Triblock Copolymers Containing Complementary Nucleobase Molecular Recognition. Macromolecules 2007. [DOI: 10.1021/ma070865y] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian D. Mather
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
| | - Margaux B. Baker
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
| | - Frederick L. Beyer
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
| | - Michael A. G. Berg
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
| | - Matthew D. Green
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
| | - Timothy E. Long
- Macromolecules and Interfaces Institute, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0344, and Army Research Laboratory, Materials Division, Aberdeen Proving Ground, Aberdeen, Maryland 21005
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Ghosal G, Muniyappa K. The characterization of Saccharomyces cerevisiae Mre11/Rad50/Xrs2 complex reveals that Rad50 negatively regulates Mre11 endonucleolytic but not the exonucleolytic activity. J Mol Biol 2007; 372:864-882. [PMID: 17698079 DOI: 10.1016/j.jmb.2007.07.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/04/2007] [Accepted: 07/09/2007] [Indexed: 12/29/2022]
Abstract
The evolutionarily conserved heterotrimeric Mre11/Rad50/Xrs2 (Nbs1) (MRX/N) complex plays a central role in an array of cellular responses involving DNA damage, telomere length homeostasis, cell-cycle checkpoint control and meiotic recombination. The underlying biochemical functions of MRX/N complex, or each of its individual subunits, at telomeres and the importance of complex formation are poorly understood. Here, we show that the Saccharomyces cerevisiae MRX complex, or its subunits, display an overwhelming preference for G-quadruplex DNA than for telomeric single-stranded or double-stranded DNA implicating the possible existence of this DNA structure in vivo. Although these alternative DNA substrates failed to affect Rad50 ATPase activity, kinetic analyses revealed that interaction of Rad50 with Xrs2 and/or Mre11 led to a twofold increase in the rates of ATP hydrolysis. Significantly, we show that Mre11 displays sequence-specific double-stranded DNA endonuclease activity, and Rad50, but not Xrs2, abrogated endonucleolytic but not the exonucleolytic activity. This repression was alleviated upon ATP hydrolysis by Rad50, suggesting that complex formation between Rad50 and Mre11 might be important for blocking the inappropriate cleavage of genomic DNA. Mre11 alone, or in the presence of ATP, MRX, MR or MX sub-complexes cleaved at the 5' end of an array of G residues in single-stranded DNA, at G quartets in G4 DNA, and at the center of TGTG repeats in duplex DNA. We propose that negative regulation of Mre11 endonuclease activity by Rad50 might be important for native as well as de novo telomere length homeostasis.
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Affiliation(s)
- Gargi Ghosal
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
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Sun H, Xiang J, Tang Y, Xu G. Regulation and recognization of the extended G-quadruplex by rutin. Biochem Biophys Res Commun 2006; 352:942-6. [PMID: 17157807 DOI: 10.1016/j.bbrc.2006.11.125] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 11/27/2006] [Indexed: 01/26/2023]
Abstract
Rutins, a kind of flavonoid glycoside, showed different absorption and fluorescence spectral characteristics when bound to blunt-end stacked and interlocked extended G-quadruplexes. Further (1)H NMR spectra showed these two extended G-quadruplexes bound with rutins in different manners: after binding, the blunt-end stacked extended G-quadruplexes were decomposed to monomers, and the interlocked extended G-quadruplexes did not change. Based on these spectral features, one may expect the usage of rutins in recognizing different structural extended G-quadruplexes and regulating the ratio between blunt-end stacked extended G-quadruplexes and monomers.
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Affiliation(s)
- Hongxia Sun
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, PR China
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