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Esnault C, Magat T, Zine El Aabidine A, Garcia-Oliver E, Cucchiarini A, Bouchouika S, Lleres D, Goerke L, Luo Y, Verga D, Lacroix L, Feil R, Spicuglia S, Mergny JL, Andrau JC. G4access identifies G-quadruplexes and their associations with open chromatin and imprinting control regions. Nat Genet 2023; 55:1359-1369. [PMID: 37400615 DOI: 10.1038/s41588-023-01437-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 05/31/2023] [Indexed: 07/05/2023]
Abstract
Metazoan promoters are enriched in secondary DNA structure-forming motifs, such as G-quadruplexes (G4s). Here we describe 'G4access', an approach to isolate and sequence G4s associated with open chromatin via nuclease digestion. G4access is antibody- and crosslinking-independent and enriches for computationally predicted G4s (pG4s), most of which are confirmed in vitro. Using G4access in human and mouse cells, we identify cell-type-specific G4 enrichment correlated with nucleosome exclusion and promoter transcription. G4access allows measurement of variations in G4 repertoire usage following G4 ligand treatment, HDAC and G4 helicases inhibitors. Applying G4access to cells from reciprocal hybrid mouse crosses suggests a role for G4s in the control of active imprinting regions. Consistently, we also observed that G4access peaks are unmethylated, while methylation at pG4s correlates with nucleosome repositioning on DNA. Overall, our study provides a new tool for studying G4s in cellular dynamics and highlights their association with open chromatin, transcription and their antagonism to DNA methylation.
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Affiliation(s)
- Cyril Esnault
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Talha Magat
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Amal Zine El Aabidine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Encar Garcia-Oliver
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Anne Cucchiarini
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
| | - Soumya Bouchouika
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - David Lleres
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Lutz Goerke
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Yu Luo
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
- Université Paris-Saclay, Institut Curie, Orsay, France
| | - Daniela Verga
- Université Paris-Saclay, Institut Curie, Orsay, France
| | - Laurent Lacroix
- Institut de Biologie de l'École Normale Supérieure, ENS, CNRS UMR8197, Inserm U1024, Paris, France
| | - Robert Feil
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Salvatore Spicuglia
- Aix-Marseille University, INSERM, TAGC, UMR 1090, Marseille, France
- Equipe Labellisée Ligue Contre le Cancer, Marseille, France
| | - Jean-Louis Mergny
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
| | - Jean-Christophe Andrau
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France.
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Zhang Y, Huang J, Yu K, Cui X. G-Quadruplexes Formation by the C9orf72 Nucleotide Repeat Expansion d(GGGGCC) n and Conformation Regulation by Fangchinoline. Molecules 2023; 28:4671. [PMID: 37375224 DOI: 10.3390/molecules28124671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/01/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
The G-quadruplex (GQ)-forming hexanucleotide repeat expansion (HRE) in the C9orf72 (C9) gene has been found to be the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (collectively, C9ALS/FTD), implying the great significance of modulating C9-HRE GQ structures in C9ALS/FTD therapeutic treatment strategies. In this study, we investigated the GQ structures formed by varied lengths of C9-HRE DNA sequences d(GGGGCC)4 (C9-24mer) and d(GGGGCC)8 (C9-48mer), and found that the C9-24mer forms anti-parallel GQ (AP-GQ) in the presence of potassium ions, while the long C9-48mer bearing eight guanine tracts forms unstacked tandem GQ consisting of two C9-24mer unimolecular AP-GQs. Moreover, the natural small molecule Fangchinoline was screened out in order to be able to stabilize and alter the C9-HRE DNA to parallel GQ topology. Further study of the interaction of Fangchinoline with the C9-HRE RNA GQ unit r(GGGGCC)4 (C9-RNA) revealed that it can also recognize and improve the thermal stability of C9-HRE RNA GQ. Finally, use of AutoDock simulation results indicated that Fangchinoline binds to the groove regions of the parallel C9-HRE GQs. These findings pave the way for further studies of GQ structures formed by pathologically related long C9-HRE sequences, and also provide a natural small-molecule ligand that modulates the structure and stability of C9-HRE GQ, both in DNA and RNA levels. Altogether, this work may contribute to therapeutic approaches of C9ALS/FTD which take the upstream C9-HRE DNA region, as well as the toxic C9-HRE RNA, as targets.
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Affiliation(s)
- Yun Zhang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Junliu Huang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Kainan Yu
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Xiaojie Cui
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
- Key Laboratory of Ecology and Environment in Minority Areas (Minzu University of China), National Ethnic Affairs Commission, Beijing 100081, China
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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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