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Oikeh E, Ziebarth J, Dinar MAM, Kirchhoff D, Aronova A, Dziubla TD, Wang Y, DeRouchey JE. DNA Packaging and Polycation Length Determine DNA Susceptibility to Free Radical Damage in Condensed DNA. J Phys Chem B 2024; 128:3329-3339. [PMID: 38557033 DOI: 10.1021/acs.jpcb.3c06116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
In nature, DNA exists primarily in a highly compacted form. The compaction of DNA in vivo is mediated by cationic proteins: histones in somatic nuclei and protamines in sperm chromatin. The extreme, nearly crystalline packaging of DNA by protamines in spermatozoa is thought to be essential for both efficient genetic delivery as well as DNA protection against damage by mutagens and oxidative species. The protective role of protamines is required in sperm, as they are sensitive to ROS damage due to the progressive loss of DNA repair mechanisms during maturation. The degree to which DNA packaging directly relates to DNA protection in the condensed state, however, is poorly understood. Here, we utilized different polycation condensing agents to achieve varying DNA packaging densities and quantify DNA damage by free radical oxidation within the condensates. Although we see that tighter DNA packaging generally leads to better protection, the length of the polycation also plays a significant role. Molecular dynamics simulations suggest that longer polyarginine chains offer increased protection by occupying more space on the DNA surface and forming more stable interactions. Taken together, our results suggest a complex interplay among polycation properties, DNA packaging density, and DNA protection against free radical damage within condensed states.
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Affiliation(s)
- Ehigbai Oikeh
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Jesse Ziebarth
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
| | - Md Abu Monsur Dinar
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Daniel Kirchhoff
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Anastasiia Aronova
- Chemical and Materials Engineering Department, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Thomas D Dziubla
- Chemical and Materials Engineering Department, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Yongmei Wang
- Department of Chemistry, University of Memphis, Memphis, Tennessee 38152, United States
| | - Jason E DeRouchey
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
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2
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Shibata Y. Repeat sequence corresponding to the nucleosome length at the opposite end of the pairing center on autosomes in C. elegans. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001079. [PMID: 38454953 PMCID: PMC10918474 DOI: 10.17912/micropub.biology.001079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/18/2023] [Accepted: 02/20/2024] [Indexed: 03/09/2024]
Abstract
Many repeat sequences in genomes have unknown functions, but some have features that are suggestive of one. I found a repeat sequence that has 185 base pairs as the basic unit, which is the same as the length of a nucleosome repeat. The chromosomal location of this repeat sequence is opposite the pairing center of each autosomal chromosome. I named this repeat sequence Nucleosome Length Autosomal Repeat (NLAR). The NLAR regions reveal a low level of H3K79me, which is required for chromosome pairing. I hypothesize that NLAR inhibits chromosome pairing of autosomes from inappropriate ends during meiosis.
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3
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Liu C, Yu J, Song A, Wang M, Hu J, Chen P, Zhao J, Li G. Histone H1 facilitates restoration of H3K27me3 during DNA replication by chromatin compaction. Nat Commun 2023; 14:4081. [PMID: 37429872 DOI: 10.1038/s41467-023-39846-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/30/2023] [Indexed: 07/12/2023] Open
Abstract
During cell renewal, epigenetic information needs to be precisely restored to maintain cell identity and genome integrity following DNA replication. The histone mark H3K27me3 is essential for the formation of facultative heterochromatin and the repression of developmental genes in embryonic stem cells. However, how the restoration of H3K27me3 is precisely achieved following DNA replication is still poorly understood. Here we employ ChOR-seq (Chromatin Occupancy after Replication) to monitor the dynamic re-establishment of H3K27me3 on nascent DNA during DNA replication. We find that the restoration rate of H3K27me3 is highly correlated with dense chromatin states. In addition, we reveal that the linker histone H1 facilitates the rapid post-replication restoration of H3K27me3 on repressed genes and the restoration rate of H3K27me3 on nascent DNA is greatly compromised after partial depletion of H1. Finally, our in vitro biochemical experiments demonstrate that H1 facilitates the propagation of H3K27me3 by PRC2 through compacting chromatin. Collectively, our results indicate that H1-mediated chromatin compaction facilitates the propagation and restoration of H3K27me3 after DNA replication.
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Affiliation(s)
- Cuifang Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Juan Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Aoqun Song
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Min Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Jiansen Hu
- Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Science, 100101, Beijing, China
| | - Ping Chen
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
- Department of Immunology, School of Basic Medical Sciences, Beijing Key Laboratory for Tumor Invasion and Metastasis, Capital Medical University, 100069, Beijing, China
| | - Jicheng Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, TaiKang Center for Life and Medical Sciences, Wuhan University, 430072, Wuhan, China.
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Zhang Z, Wang J, Zhang X, Guan X, Gao T, Mao Y, Poetsch A, Wang D. ChIP-Based Nuclear DNA Isolation for Genome Sequencing in Pyropia to Remove Cytosol and Bacterial DNA Contamination. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12091883. [PMID: 37176941 PMCID: PMC10181236 DOI: 10.3390/plants12091883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/20/2023] [Accepted: 04/29/2023] [Indexed: 05/15/2023]
Abstract
Contamination from cytosolic DNA (plastid and mitochondrion) and epiphytic bacteria is challenging the efficiency and accuracy of genome-wide analysis of nori-producing marine seaweed Pyropia yezoensis. Unlike bacteria and organellar DNA, Pyropia nuclear DNA is closely associated with histone proteins. In this study, we applied Chromatin Immunoprecipitation (ChIP) of histone H3 to isolate nuclear DNA, followed by high-throughput sequencing. More than 99.41% of ChIP-sequencing data were successfully aligned to the reference nuclear genome; this was remarkably higher than those from direct extraction and direct extraction data, in which 40.96% to 42.95% are from plastids. The proportion of data that were mapped to the bacterial database when using ChIP extraction was very low. Additionally, ChIP data can cover up to 89.00% of the nuclear genome, higher than direct extraction data at equal data size and comparable to the latter at equal sequencing depth. The uncovered regions from the three methods are mostly overlapping, suggesting that incomplete sequencing accounts for the missing data, rather than failed chromatin-antibody binding in the ChIP extraction method. This ChIP extraction method can successfully separate nuclear DNA from cytosolic DNA and bacterial DNA, thus overwhelmingly reducing the sequencing cost in a genome resequencing project and providing strictly purified reference data for genome assembly. The method's applicability to other macroalgae makes it a valuable contribution to the algal research community.
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Affiliation(s)
- Zehao Zhang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
| | - Junhao Wang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
| | - Xiaoqian Zhang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
| | - Xiaowei Guan
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
| | - Tian Gao
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
| | - Yunxiang Mao
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources (Hainan Tropical Ocean University), Ministry of Education, Sanya 572000, China
| | - Ansgar Poetsch
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- Department of Plant Biochemistry, Ruhr University Bochum, 44787 Bochum, Germany
| | - Dongmei Wang
- Key Laboratory of Marine Genetics and Breeding (OUC), Ministry of Education, Qingdao 266000, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266000, China
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5
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The influence of high-order chromatin state in the regulation of stem cell fate. Biochem Soc Trans 2022; 50:1809-1822. [DOI: 10.1042/bst20220763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022]
Abstract
In eukaryotic cells, genomic DNA is hierarchically compacted by histones into chromatin, which is initially assembled by the nucleosome and further folded into orderly and flexible structures that include chromatin fiber, chromatin looping, topologically associated domains (TADs), chromosome compartments, and chromosome territories. These distinct structures and motifs build the three-dimensional (3D) genome architecture, which precisely controls spatial and temporal gene expression in the nucleus. Given that each type of cell is characterized by its own unique gene expression profile, the state of high-order chromatin plays an essential role in the cell fate decision. Accumulating evidence suggests that the plasticity of high-order chromatin is closely associated with stem cell fate. In this review, we summarize the biological roles of the state of high-order chromatin in embryogenesis, stem cell differentiation, the maintenance of stem cell identity, and somatic cell reprogramming. In addition, we highlight the roles of epigenetic factors and pioneer transcription factors (TFs) involved in regulating the state of high-order chromatin during the determination of stem cell fate and discuss how H3K9me3-heterochromatin restricts stem cell fate. In summary, we review the most recent progress in research on the regulatory functions of high-order chromatin dynamics in the determination and maintenance of stem cell fate.
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Arora H, Singh RK, Sharma S, Sharma N, Panchal A, Das T, Prasad A, Prasad M. DNA methylation dynamics in response to abiotic and pathogen stress in plants. PLANT CELL REPORTS 2022; 41:1931-1944. [PMID: 35833989 DOI: 10.1007/s00299-022-02901-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
DNA methylation is a dynamic epigenetic mechanism that plays a significant role in gene expression and also maintains chromatin stability. The process is conserved in both plants and animals, and crucial for development and stress responses. Differential DNA methylation during adverse environmental conditions or pathogen attack facilitates the selective expression of defense-related genes. Both stress-induced DNA hypomethylation and hypermethylation play beneficial roles in activating the defense response. These DNA marks may be carried to the next generation making the progenies 'primed' for abiotic and biotic stress responses. Over the recent years, rapid advancements in the area of high throughput sequencing have enabled the detection of methylation status at genome levels in several plant species. Epigenotyping offers an alternative tool to plant breeders in addition to conventional markers for the selection of the desired offspring. In this review, we briefly discuss the mechanism of DNA methylation, recent understanding of DNA methylation-mediated gene regulation during abiotic and biotic stress responses, and stress memory in plants.
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Affiliation(s)
- Heena Arora
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Roshan Kumar Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Shambhavi Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Namisha Sharma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
- Institute of Life Sciences, NALCO Nagar, Bhubaneswar, 751023, India
| | - Anurag Panchal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Tuhin Das
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ashish Prasad
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Manoj Prasad
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
- Department of Plant Sciences, University of Hyderabad, Hyderabad, Telangana, 500046, India.
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7
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Mlodawska OW, Saini P, Parker JB, Wei JJ, Bulun SE, Simon MA, Chakravarti D. Epigenomic and enhancer dysregulation in uterine leiomyomas. Hum Reprod Update 2022; 28:518-547. [PMID: 35199155 PMCID: PMC9247409 DOI: 10.1093/humupd/dmac008] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/16/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Uterine leiomyomas, also known as uterine fibroids or myomas, are the most common benign gynecological tumors and are found in women of reproductive and postmenopausal age. There is an exceptionally high prevalence of this tumor in women by the age of 50 years. Black women are particularly affected, with an increased incidence, earlier age of onset, larger and faster growing fibroids and greater severity of symptoms as compared to White women. Although advances in identifying genetic and environmental factors to delineate these fibroids have already been made, only recently has the role of epigenomics in the pathogenesis of this disease been considered. OBJECTIVE AND RATIONALE Over recent years, studies have identified multiple epigenomic aberrations that may contribute to leiomyoma development and growth. This review will focus on the most recent discoveries in three categories of epigenomic changes found in uterine fibroids, namely aberrant DNA methylation, histone tail modifications and histone variant exchange, and their translation into altered target gene architecture and transcriptional outcome. The findings demonstrating how the altered 3D shape of the enhancer can regulate gene expression from millions of base pairs away will be discussed. Additionally, translational implications of these discoveries and potential roadblocks in leiomyoma treatment will be addressed. SEARCH METHODS A comprehensive PubMed search was performed to identify published articles containing keywords relevant to the focus of the review, such as: uterine leiomyoma, uterine fibroids, epigenetic alterations, epigenomics, stem cells, chromatin modifications, extracellular matrix [ECM] organization, DNA methylation, enhancer, histone post-translational modifications and dysregulated gene expression. Articles until September 2021 were explored and evaluated to identify relevant updates in the field. Most of the articles focused on in the discussion were published between 2015 and 2021, although some key discoveries made before 2015 were included for background information and foundational purposes. We apologize to the authors whose work was not included because of space restrictions or inadvertent omission. OUTCOMES Chemical alterations to the DNA structure and of nucleosomal histones, without changing the underlying DNA sequence, have now been implicated in the phenotypic manifestation of uterine leiomyomas. Genome-wide DNA methylation analysis has revealed subsets of either suppressed or overexpressed genes accompanied by aberrant promoter methylation. Furthermore, differential promoter access resulting from altered 3D chromatin structure and histone modifications plays a role in regulating transcription of key genes thought to be involved in leiomyoma etiology. The dysregulated genes function in tumor suppression, apoptosis, angiogenesis, ECM formation, a variety of cancer-related signaling pathways and stem cell differentiation. Aberrant DNA methylation or histone modification is also observed in altering enhancer architecture, which leads to changes in enhancer-promoter contact strength, producing novel explanations for the overexpression of high mobility group AT-hook 2 and gene dysregulation found in mediator complex subunit 12 mutant fibroids. While many molecular mechanisms and epigenomic features have been investigated, the basis for the racial disparity observed among those in the Black population remains unclear. WIDER IMPLICATIONS A comprehensive understanding of the exact pathogenesis of uterine leiomyoma is lacking and requires attention as it can provide clues for prevention and viable non-surgical treatment. These findings will widen our knowledge of the role epigenomics plays in the mechanisms related to uterine leiomyoma development and highlight novel approaches for the prevention and identification of epigenome targets for long-term non-invasive treatment options of this significantly common disease.
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Affiliation(s)
| | | | - J Brandon Parker
- Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jian-Jun Wei
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA,Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, IL 60611, USA
| | - Serdar E Bulun
- Division of Reproductive Science in Medicine, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Melissa A Simon
- Department of Obstetrics and Gynecology, Center for Health Equity Transformation, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Debabrata Chakravarti
- Correspondence address. Department of Obstetrics and Gynecology, Northwestern University, Feinberg School of Medicine, 303 E Superior Street, Lurie 4-119, Chicago, IL 60611, USA. E-mail:
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Abstract
Actin is a highly conserved protein in mammals. The actin dynamics is regulated by actin-binding proteins and actin-related proteins. Nuclear actin and these regulatory proteins participate in multiple nuclear processes, including chromosome architecture organization, chromatin remodeling, transcription machinery regulation, and DNA repair. It is well known that the dysfunctions of these processes contribute to the development of cancer. Moreover, emerging evidence has shown that the deregulated actin dynamics is also related to cancer. This chapter discusses how the deregulation of nuclear actin dynamics contributes to tumorigenesis via such various nuclear events.
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Affiliation(s)
- Yuanjian Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shengzhe Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jae-Il Park
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center and Health Science Center, Houston, TX, USA.
- Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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9
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Kanapeckaitė A, Burokienė N, Mažeikienė A, Cottrell GS, Widera D. Biophysics is reshaping our perception of the epigenome: from DNA-level to high-throughput studies. BIOPHYSICAL REPORTS 2021; 1:100028. [PMID: 36425454 PMCID: PMC9680810 DOI: 10.1016/j.bpr.2021.100028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 09/24/2021] [Indexed: 06/16/2023]
Abstract
Epigenetic research holds great promise to advance our understanding of biomarkers and regulatory processes in health and disease. An increasing number of new approaches, ranging from molecular to biophysical analyses, enable identifying epigenetic changes on the level of a single gene or the whole epigenome. The aim of this review is to highlight how the field is shifting from completely molecular-biology-driven solutions to multidisciplinary strategies including more reliance on biophysical analysis tools. Biophysics not only offers technical advancements in imaging or structure analysis but also helps to explore regulatory interactions. New computational methods are also being developed to meet the demand of growing data volumes and their processing. Therefore, it is important to capture these new directions in epigenetics from a biophysical perspective and discuss current challenges as well as multiple applications of biophysical methods and tools. Specifically, we gradually introduce different biophysical research methods by first considering the DNA-level information and eventually higher-order chromatin structures. Moreover, we aim to highlight that the incorporation of bioinformatics, machine learning, and artificial intelligence into biophysical analysis allows gaining new insights into complex epigenetic processes. The gained understanding has already proven useful in translational and clinical research providing better patient stratification options or new therapeutic insights. Together, this offers a better readiness to transform bench-top experiments into industrial high-throughput applications with a possibility to employ developed methods in clinical practice and diagnostics.
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Affiliation(s)
- Austė Kanapeckaitė
- Algorithm379, Laisvės g. 7, LT 12007, Vilnius, Lithuania
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
| | - Neringa Burokienė
- Clinics of Internal Diseases, Family Medicine and Oncology, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | - Asta Mažeikienė
- Department of Physiology, Biochemistry, Microbiology and Laboratory Medicine, Institute of Biomedical Sciences, Faculty of Medicine, M. K. Čiurlionio str. 21/27, LT-03101 Vilnius, Lithuania
| | | | - Darius Widera
- Reading School of Pharmacy, Whiteknights, Reading, UK, RG6 6UB
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Dey P, Mattick JS. High frequency of intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs. Epigenetics Chromatin 2021; 14:45. [PMID: 34579770 PMCID: PMC8477579 DOI: 10.1186/s13072-021-00419-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It is established that protein-coding exons are preferentially localized in nucleosomes. To examine whether the same is true for non-coding exons, we analysed nucleosome occupancy in and adjacent to internal exons in genes encoding long non-coding RNAs (lncRNAs) in human CD4+ T cells and K562 cells. RESULTS We confirmed that internal exons in lncRNAs are preferentially associated with nucleosomes, but also observed an elevated signal from H3K4me3-marked nucleosomes in the sequences upstream of these exons. Examination of 200 genomic lncRNA loci chosen at random across all chromosomes showed that high-density regions of H3K4me3-marked nucleosomes, which we term 'slabs', are associated with genomic regions exhibiting intron retention. These retained introns occur in over 50% of lncRNAs examined and are mostly first introns with an average length of just 354 bp, compared to the average length of all human introns of 6355 and 7987 bp in mRNAs and lncRNAs, respectively. Removal of short introns from the dataset abrogated the high upstream H3K4me3 signal, confirming that the association of slabs and short lncRNA introns with intron retention holds genome-wide. The high upstream H3K4me3 signal is also associated with alternatively spliced exons, known to be prominent in lncRNAs. This phenomenon was not observed with mRNAs. CONCLUSIONS There is widespread intron retention and clustered H3K4me3-marked nucleosomes in short first introns of human long non-coding RNAs, which raises intriguing questions about the relationship of IR to lncRNA function and chromatin organization.
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Affiliation(s)
- Pinki Dey
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia
| | - John S Mattick
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, 2052, Sydney, Australia.
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11
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Mechanisms of organelle elimination for lens development and differentiation. Exp Eye Res 2021; 209:108682. [PMID: 34214522 DOI: 10.1016/j.exer.2021.108682] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/03/2021] [Accepted: 06/19/2021] [Indexed: 12/23/2022]
Abstract
A hallmark feature of lens development and differentiation is the complete elimination of organelles from the center of the eye lens. A long unanswered question in lens biology is what are the mechanisms that control the elimination of organelles during the terminal remodeling program to form mature lens fiber cells? Recent advances have expanded our understanding of these mechanisms including newly discovered signaling pathways, proteasomal regulators, autophagy proteins, transcription factors and the hypoxic environment of the lens itself. These recent discoveries suggest that distinct mechanisms coordinate the elimination of the nucleus, mitochondria, endoplasmic reticulum and Golgi apparatus during lens fiber cell differentiation. Since regulation of organelle number and distribution is also a feature of the terminal remodeling programs of more complex cell-types and tissues, these advances are likely to impact a wide-variety of fields.
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12
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Miriklis EL, Rozario AM, Rothenberg E, Bell TDM, Whelan DR. Understanding DNA organization, damage, and repair with super-resolution fluorescence microscopy. Methods Appl Fluoresc 2021; 9. [PMID: 33765677 DOI: 10.1088/2050-6120/abf239] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 03/25/2021] [Indexed: 11/12/2022]
Abstract
Super-resolution microscopy (SRM) comprises a suite of techniques well-suited to probing the nanoscale landscape of genomic function and dysfunction. Offering the specificity and sensitivity that has made conventional fluorescence microscopy a cornerstone technique of biological research, SRM allows for spatial resolutions as good as 10 nanometers. Moreover, single molecule localization microscopies (SMLMs) enable examination of individual molecular targets and nanofoci allowing for the characterization of subpopulations within a single cell. This review describes how key advances in both SRM techniques and sample preparation have enabled unprecedented insights into DNA structure and function, and highlights many of these new discoveries. Ongoing development and application of these novel, highly interdisciplinary SRM assays will continue to expand the toolbox available for research into the nanoscale genomic landscape.
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Affiliation(s)
| | | | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, United States of America
| | - Toby D M Bell
- School of Chemistry, Monash University, Clayton, VIC, Australia
| | - Donna R Whelan
- Department of Pharmacy and Biomedical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo, VIC, Australia
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Zhou Z, Yan R, Jiang W, Irudayaraj JMK. Chromatin hierarchical branching visualized at the nanoscale by electron microscopy. NANOSCALE ADVANCES 2021; 3:1019-1028. [PMID: 34381959 PMCID: PMC8323808 DOI: 10.1039/d0na00359j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/12/2020] [Indexed: 06/13/2023]
Abstract
Chromatin is spatially organized in a hierarchical manner by virtue of single nucleosomes condensing into higher order chromatin structures, conferring various mechanical properties and biochemical signals. These higher order chromatin structures regulate genomic function by organization of the heterochromatin and euchromatin landscape. Less is known about its transition state from higher order heterochromatin to the lower order nucleosome form, and there is no information on its physical properties. We have developed a facile method of electron microscopy visualization to reveal the interphase chromatin in eukaryotic cells and its organization into hierarchical branching structures. We note that chromatin hierarchical branching can be distinguished at four levels, clearly indicating the stepwise transition from heterochromatin to euchromatin. The protein-DNA density across the chromatin fibers decreases during the transition from compacted heterochromatin to dispersed euchromatin. Moreover, the thickness of the chromatin ranges between 10 to 270 nm, and the controversial 30 nm chromatin fiber exists as a prominent intermediate structure. This study provides important insights into higher order chromatin organization which plays a key role in diseases such as cancer.
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Affiliation(s)
- Zhongwu Zhou
- Bindley Bioscience Center, Department of Agricultural and Biological Engineering, Purdue University West Lafayette IN 47907 USA
- The University of Texas at Austin NHB 4.120, 100 E. 24th St. Austin TX 78712 USA
| | - Rui Yan
- Markey Center for Structural Biology, Department of Biological Science, Purdue University West Lafayette IN 47907 USA
- Howard Hughes Medical Institute, Janelia Research Campus 19700 Helix Drive Asburn Virginia 20147 USA
| | - Wen Jiang
- Markey Center for Structural Biology, Department of Biological Science, Purdue University West Lafayette IN 47907 USA
| | - Joseph M K Irudayaraj
- Bindley Bioscience Center, Department of Agricultural and Biological Engineering, Purdue University West Lafayette IN 47907 USA
- Cancer Center at Illinois, Department of Bioengineering, College of Engineering, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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14
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Zarreen F, Chakraborty S. Epigenetic regulation of geminivirus pathogenesis: a case of relentless recalibration of defence responses in plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6890-6906. [PMID: 32869846 DOI: 10.1093/jxb/eraa406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 08/27/2020] [Indexed: 06/11/2023]
Abstract
Geminiviruses constitute one of the largest families of plant viruses and they infect many economically important crops. The proteins encoded by the single-stranded DNA genome of these viruses interact with a wide range of host proteins to cause global dysregulation of cellular processes and help establish infection in the host. Geminiviruses have evolved numerous mechanisms to exploit host epigenetic processes to ensure the replication and survival of the viral genome. Here, we review our current knowledge of diverse epigenetic processes that have been implicated in the regulation of geminivirus pathogenesis, including DNA methylation, histone post-transcriptional modification, chromatin remodelling, and nucleosome repositioning. In addition, we discuss the currently limited evidence of host epigenetic defence responses that are aimed at counteracting geminivirus infection, and the potential for exploiting these responses for the generation of resistance against geminiviruses in crop species.
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Affiliation(s)
- Fauzia Zarreen
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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15
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Al-Natour Z, Chalissery J, Hassan AH. Fun30 chromatin remodeler helps in dealing with torsional stress and camptothecin-induced DNA damage. Yeast 2020; 38:170-182. [PMID: 33141948 DOI: 10.1002/yea.3534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 10/04/2020] [Accepted: 10/26/2020] [Indexed: 12/19/2022] Open
Abstract
Fun30 is an ATP-dependent chromatin remodeler in budding yeast that is involved in cellular processes important for maintaining genomic stability such as gene silencing and DNA damage repair. Cells lacking Fun30 are moderately sensitive to the topoisomerase inhibitor camptothecin and exhibit a delay in cell cycle progression in the presence of camptothecin. Here, we show that Fun30 is required to cope with torsional stress in the absence of Top1. Moreover, we show through genetic studies that Fun30 acts in a parallel pathway to Mus81 endonuclease but is epistatic to Tdp1 phosphodiesterase and Rad1 endonuclease in the repair of camptothecin-induced DNA damage. More importantly, we show that DNA damage sensitivity of Fun30 deficient cells is enhanced in the absence of RNase H enzymes that remove RNA:DNA hybrids. We believe that chromatin remodeling by Fun30 may be important in dealing with torsional stress and camptothecin-induced DNA damage.
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Affiliation(s)
- Zeina Al-Natour
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Jisha Chalissery
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ahmed H Hassan
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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16
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Peng J, Yuan C, Hua X, Zhang Z. Molecular mechanism of histone variant H2A.B on stability and assembly of nucleosome and chromatin structures. Epigenetics Chromatin 2020; 13:28. [PMID: 32664941 PMCID: PMC7362417 DOI: 10.1186/s13072-020-00351-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 07/09/2020] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND H2A.B, the most divergent histone variant of H2A, can significantly modulate nucleosome and chromatin structures. However, the related structural details and the underlying mechanism remain elusive to date. In this work, we built atomic models of the H2A.B-containing nucleosome core particle (NCP), chromatosome, and chromatin fiber. Multiscale modeling including all-atom molecular dynamics and coarse-grained simulations were then carried out for these systems. RESULTS It is found that sequence differences at the C-terminal tail, the docking domain, and the L2 loop, between H2A.B and H2A are directly responsible for the DNA unwrapping in the H2A.B NCP, whereas the N-terminus of H2A.B may somewhat compensate for the aforementioned unwrapping effect. The assembly of the H2A.B NCP is more difficult than that of the H2A NCP. H2A.B may also modulate the interactions of H1 with both the NCP and the linker DNA and could further affect the higher-order structure of the chromatin fiber. CONCLUSIONS The results agree with the experimental results and may shed new light on the biological function of H2A.B. Multiscale modeling may be a valuable tool for investigating structure and dynamics of the nucleosome and the chromatin induced by various histone variants.
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Affiliation(s)
- Junhui Peng
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics, National Science Center for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.,Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY, 10065, USA
| | - Chuang Yuan
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics, National Science Center for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - Xinfan Hua
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics, National Science Center for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - Zhiyong Zhang
- MOE Key Laboratory for Membraneless Organelles & Cellular Dynamics, National Science Center for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.
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17
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Zhang Z, Wang Q, Liu Y, Sun Q, Li H, Czajkowsky DM, Shao Z. Massive reorganization of the genome during primary monocyte differentiation into macrophage. Acta Biochim Biophys Sin (Shanghai) 2020; 52:546-553. [PMID: 32324846 DOI: 10.1093/abbs/gmaa026] [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] [Received: 12/26/2019] [Revised: 12/20/2019] [Accepted: 02/24/2020] [Indexed: 12/13/2022] Open
Abstract
Monocyte-to-macrophage trans-differentiation has long been studied to better understand this immunological response and aspects of developmental processes more generally. A key question is the nature of the corresponding changes in chromatin conformation and its relationship to the transcriptome during this process. This question is especially intriguing since this trans-differentiation is not associated with progression through mitosis, often considered a necessary step for gross changes in chromosomal structure. Here, we characterized the transcriptional and genomic structural changes during macrophage development of primary human monocytes using RNA-seq and in situ Hi-C. We found that, during this transition, the genome architecture undergoes a massive remodeling to a degree not observed before between structured genomes, with changes in ~90% of the topologically associating domains (TADs). These changes in the TADs are associated with changed expression of immunological genes. These structural changes, however, differ extensively from those described recently in a study of the leukemia cell line, THP-1. Furthermore, up-regulation of the AP-1 family of genes that effected functionally important changes in the genomic structure during the differentiation of the THP-1 cells was not corroborated with the primary cells. Taken together, our results provide a comprehensive characterization of the changes in genomic structure during the monocyte-to-macrophage transition, establish a framework for the elucidation of processes underlying differentiation without proliferation, and demonstrate the importance of verifying with primary cells the mechanisms discovered with cultured cells.
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Affiliation(s)
- Zhipeng Zhang
- State Key Laboratory for Oncogenes and Related Genes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qi Wang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Science and Technology, Shanghai Key Laboratory of Signaling and Disease Research, Tongji University, Shanghai 200092, China
| | - Yulong Liu
- State Key Laboratory for Oncogenes and Related Genes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiu Sun
- Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hua Li
- State Key Laboratory for Oncogenes and Related Genes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Daniel M Czajkowsky
- State Key Laboratory for Oncogenes and Related Genes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhifeng Shao
- State Key Laboratory for Oncogenes and Related Genes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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18
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Li G. The 3D organization of genome in the nucleus: from the nucleosome to the 4D nucleome. SCIENCE CHINA-LIFE SCIENCES 2020; 63:791-794. [PMID: 32394246 DOI: 10.1007/s11427-020-1723-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Guohong Li
- National laboratory of Bio-macromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing, 100101, China.
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19
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Small Molecules Targeting the Specific Domains of Histone-Mark Readers in Cancer Therapy. Molecules 2020; 25:molecules25030578. [PMID: 32013155 PMCID: PMC7037402 DOI: 10.3390/molecules25030578] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 12/11/2022] Open
Abstract
Epigenetic modifications (or epigenetic tags) on DNA and histones not only alter the chromatin structure, but also provide a recognition platform for subsequent protein recruitment and enable them to acquire executive instructions to carry out specific intracellular biological processes. In cells, different epigenetic-tags on DNA and histones are often recognized by the specific domains in proteins (readers), such as bromodomain (BRD), chromodomain (CHD), plant homeodomain (PHD), Tudor domain, Pro-Trp-Trp-Pro (PWWP) domain and malignant brain tumor (MBT) domain. Recent accumulating data reveal that abnormal intracellular histone modifications (histone marks) caused by tumors can be modulated by small molecule-mediated changes in the activity of the above domains, suggesting that small molecules targeting histone-mark reader domains may be the trend of new anticancer drug development. Here, we summarize the protein domains involved in histone-mark recognition, and introduce recent research findings about small molecules targeting histone-mark readers in cancer therapy.
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20
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Saurabh S, Jang YH, Lansac Y, Maiti PK. Orientation Dependence of Inter-NCP Interaction: Insights into the Behavior of Liquid Crystal Phase and Chromatin Fiber Organization. J Phys Chem B 2019; 124:314-323. [DOI: 10.1021/acs.jpcb.9b07898] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Suman Saurabh
- GREMAN, University of Tours, CNRS UMR 7347, 37200 Tours, France
- Centre de Biophysique Moléculaire, CNRS, Rue Charles Sadron, 45071 Orléans, France
| | - Yun Hee Jang
- Department of Energy Science and Engineering, DGIST, Daegu 42988, Korea
| | - Yves Lansac
- GREMAN, University of Tours, CNRS UMR 7347, 37200 Tours, France
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris Saclay, 91405 Orsay cedex, France
| | - Prabal K. Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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21
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Di Liegro CM, Schiera G, Proia P, Di Liegro I. Physical Activity and Brain Health. Genes (Basel) 2019; 10:genes10090720. [PMID: 31533339 PMCID: PMC6770965 DOI: 10.3390/genes10090720] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/12/2019] [Indexed: 12/16/2022] Open
Abstract
Physical activity (PA) has been central in the life of our species for most of its history, and thus shaped our physiology during evolution. However, only recently the health consequences of a sedentary lifestyle, and of highly energetic diets, are becoming clear. It has been also acknowledged that lifestyle and diet can induce epigenetic modifications which modify chromatin structure and gene expression, thus causing even heritable metabolic outcomes. Many studies have shown that PA can reverse at least some of the unwanted effects of sedentary lifestyle, and can also contribute in delaying brain aging and degenerative pathologies such as Alzheimer’s Disease, diabetes, and multiple sclerosis. Most importantly, PA improves cognitive processes and memory, has analgesic and antidepressant effects, and even induces a sense of wellbeing, giving strength to the ancient principle of “mens sana in corpore sano” (i.e., a sound mind in a sound body). In this review we will discuss the potential mechanisms underlying the effects of PA on brain health, focusing on hormones, neurotrophins, and neurotransmitters, the release of which is modulated by PA, as well as on the intra- and extra-cellular pathways that regulate the expression of some of the genes involved.
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Affiliation(s)
- Carlo Maria Di Liegro
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche) (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Gabriella Schiera
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche) (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Patrizia Proia
- Department of Psychology, Educational Science and Human Movement (Dipartimento di Scienze Psicologiche, Pedagogiche, dell'Esercizio fisico e della Formazione), University of Palermo, 90128 Palermo, Italy.
| | - Italia Di Liegro
- Department of Biomedicine, Neurosciences and Advanced Diagnostics (Dipartimento di Biomedicina, Neuroscienze e Diagnostica avanzata) (Bi.N.D.), University of Palermo, 90127 Palermo, Italy.
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22
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Zhou Z, Li K, Yan R, Yu G, Gilpin CJ, Jiang W, Irudayaraj JMK. The transition structure of chromatin fibers at the nanoscale probed by cryogenic electron tomography. NANOSCALE 2019; 11:13783-13789. [PMID: 31211313 PMCID: PMC6688845 DOI: 10.1039/c9nr02042j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The naked DNA inside the nucleus interacts with proteins and RNAs forming a higher order chromatin structure to spatially and temporally control transcription in eukaryotic cells. The 30 nm chromatin fiber is one of the most important determinants of the regulation of eukaryotic transcription. However, the transition of chromatin from the 30 nm inactive higher order structure to the actively transcribed lower order nucleosomal arrays is unclear, which limits our understanding of eukaryotic transcription. Using a method to extract near-native eukaryotic chromatin, we revealed the chromatin structure at the transitional state from the 30 nm chromatin to multiple nucleosomal arrays by cryogenic electron tomography (cryo-ET). Reproducible electron microscopy images revealed that the transitional structure is a branching structure that the 30 nm chromatin hierarchically branches into lower order nucleosomal arrays, indicating chromatin compaction at different levels to control its accessibility during the interphase. We further observed that some of the chromatin fibers on the branching structure have a helix ribbon structure, while the others randomly twist together. Our finding of the chromatin helix ribbon structure on the extracted native chromatin revealed by cryo-ET indicates a complex higher order chromatin organization beyond the beads-on-a-string structure. The hierarchical branching and helix ribbon structure may provide mechanistic insights into how chromatin organization plays a central role in transcriptional regulation and other DNA-related biological processes during diseases such as cancer.
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Affiliation(s)
- Zhongwu Zhou
- Bindley Bioscience Center, Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA.
| | - Kunpeng Li
- Markey Center for Structural Biology, Department of Biological Science, Purdue University, West Lafayette, IN 47907, USA
| | - Rui Yan
- Markey Center for Structural Biology, Department of Biological Science, Purdue University, West Lafayette, IN 47907, USA
| | - Guimei Yu
- Markey Center for Structural Biology, Department of Biological Science, Purdue University, West Lafayette, IN 47907, USA
| | - Christopher J Gilpin
- Life Science Microscopy Facility, Purdue University, West Lafayette, IN 47907, USA
| | - Wen Jiang
- Markey Center for Structural Biology, Department of Biological Science, Purdue University, West Lafayette, IN 47907, USA
| | - Joseph M K Irudayaraj
- Bindley Bioscience Center, Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907, USA. and Department of Bioengineering, College of Engineering, 1103 Everitt Laboratory, 1406 W. Greet Street, Urbana, IL 61801, USA
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23
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Jang S, Song JJ. The big picture of chromatin biology by cryo-EM. Curr Opin Struct Biol 2019; 58:76-87. [PMID: 31233978 DOI: 10.1016/j.sbi.2019.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 05/10/2019] [Accepted: 05/20/2019] [Indexed: 01/07/2023]
Abstract
Modifications of chromatin structure are one of the key mechanisms regulating epigenetic gene expression. Proteins involved in chromatin modification mainly function as large multi-subunit complexes, and each component in the complex contributes to the function and activity of the complex. However, little is known about the structures of whole complexes and the mechanisms by which the chromatin-modifying complexes function, the functional roles of each component in the complexes, and how the complexes recognize the central unit of chromatin, the nucleosome. This lack of information is partially due to the lack of structural information for whole complexes. Recent advances in cryo-EM have begun to reveal the structures of whole chromatin-modifying complexes that enable us to understand the big picture of chromatin biology. In this review, we discuss the recent discoveries related to the mechanisms of chromatin-modifying complexes.
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Affiliation(s)
- Seongmin Jang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
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24
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Huang M, Huang J, Zheng Y, Sun Q. Histone acetyltransferase inhibitors: An overview in synthesis, structure-activity relationship and molecular mechanism. Eur J Med Chem 2019; 178:259-286. [PMID: 31195169 DOI: 10.1016/j.ejmech.2019.05.078] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 02/05/2023]
Abstract
Acetylation, a key component in post-translational modification regulated by HATs and HDACs, is relevant to many crucial cellular contexts in organisms. Based on crucial pharmacophore patterns and the structure of targeted proteins, HAT inhibitors are designed and modified for higher affinity and better bioactivity. However, there are still some challenges, such as cell permeability, selectivity, toxicity and synthetic availability, which limit the improvement of HAT inhibitors. So far, only few HAT inhibitors have been approved for commercialization, indicating the urgent need for more successful and effective structure-based drug design and synthetic strategies. Here, we summarized three classes of HAT inhibitors based on their sources and structural scaffolds, emphasizing on their synthetic methods and structure-activity relationships and molecular mechanisms, hoping to facilitate the development and further application of HAT inhibitors.
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Affiliation(s)
- Mengyuan Huang
- State Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Jiangkun Huang
- Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China
| | - Yongcheng Zheng
- State Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China
| | - Qiu Sun
- State Key Laboratory of Biotherapy, Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, China.
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25
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Agarwal T, Manjunath GP, Habib F, Chatterji A. Bacterial chromosome organization. I. Crucial role of release of topological constraints and molecular crowders. J Chem Phys 2019; 150:144908. [PMID: 30981230 DOI: 10.1063/1.5058214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We showed in our previous studies that just 3% cross-links (CLs), at special points along the contour of the bacterial DNA, help the DNA-polymer to get organized at micron length scales [T. Agarwal et al., J. Phys.: Condens. Matter 30, 034003 (2018) and T. Agarwal et al., EPL (Europhys. Lett.) 121, 18004 (2018)]. In this work, we investigate how does the release of topological constraints help in the "organization" of the DNA-polymer. Furthermore, we show that the chain compaction induced by the crowded environment in the bacterial cytoplasm contributes to the organization of the DNA-polymer. We model the DNA chain as a flexible bead-spring ring polymer, where each bead represents 1000 base pairs. The specific positions of the CLs have been taken from the experimental contact maps of the bacteria Caulobacter crescentus and Escherichia coli. We introduce different extents of ease of release of topological constraints in our model by systematically changing the diameter of the monomer bead. It varies from the value where chain crossing can occur freely to the value where chain crossing is disallowed. We also study the role of compaction of the chain due to molecular crowders by introducing an "effective" weak Lennard-Jones attraction between the monomers. Using Monte Carlo simulations, we show that the release of topological constraints and the crowding environment play a crucial role to obtain a unique organization of the polymer.
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Affiliation(s)
| | - G P Manjunath
- Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, New York 10016, USA
| | - Farhat Habib
- Inmobi, Cessna Business Park, Outer Ring Road, Bangalore 560103, India
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26
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van Emmerik CL, van Ingen H. Unspinning chromatin: Revealing the dynamic nucleosome landscape by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 110:1-19. [PMID: 30803691 DOI: 10.1016/j.pnmrs.2019.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 05/09/2023]
Abstract
NMR is an essential technique for obtaining information at atomic resolution on the structure, motions and interactions of biomolecules. Here, we review the contribution of NMR to our understanding of the fundamental unit of chromatin: the nucleosome. Nucleosomes compact the genome by wrapping the DNA around a protein core, the histone octamer, thereby protecting genomic integrity. Crucially, the imposed barrier also allows strict regulation of gene expression, DNA replication and DNA repair processes through an intricate system of histone and DNA modifications and a wide range of interactions between nucleosomes and chromatin factors. In this review, we describe how NMR has contributed to deciphering the molecular basis of nucleosome function. Starting from pioneering studies in the 1960s using natural abundance NMR studies, we focus on the progress in sample preparation and NMR methodology that has allowed high-resolution studies on the nucleosome and its subunits. We summarize the results and approaches of state-of-the-art NMR studies on nucleosomal DNA, histone complexes, nucleosomes and nucleosomal arrays. These studies highlight the particular strength of NMR in studying nucleosome dynamics and nucleosome-protein interactions. Finally, we look ahead to exciting new possibilities that will be afforded by on-going developments in solution and solid-state NMR. By increasing both the depth and breadth of nucleosome NMR studies, it will be possible to offer a unique perspective on the dynamic landscape of nucleosomes and its interacting proteins.
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Affiliation(s)
- Clara L van Emmerik
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands.
| | - Hugo van Ingen
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, the Netherlands.
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27
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Hsu KW, Chow SY, Su BY, Lu YH, Chen CJ, Chen WL, Cheng MY, Fan HF. The synergy between RSC, Nap1 and adjacent nucleosome in nucleosome remodeling. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:129-140. [PMID: 30593928 DOI: 10.1016/j.bbagrm.2018.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/23/2018] [Accepted: 11/30/2018] [Indexed: 12/29/2022]
Abstract
Eukaryotes have evolved a specific strategy to package DNA. The nucleosome is a 147-base-pair DNA segment wrapped around histone core proteins that plays important roles regulating DNA-dependent biosynthesis and gene expression. Chromatin remodeling complexes (RSC, Remodel the Structure of Chromatin) hydrolyze ATP to perturb DNA-histone contacts, leading to nucleosome sliding and ejection. Here, we utilized tethered particle motion (TPM) experiments to investigate the mechanism of RSC-mediated nucleosome remodeling in detail. We observed ATP-dependent RSC-mediated DNA looping and nucleosome ejection along individual mononucleosomes and dinucleosomes. We found that nucleosome assembly protein 1 (Nap1) enhanced RSC-mediated nucleosome ejection in a two-step disassembly manner from dinucleosomes but not from mononucleosomes. Based on this work, we provide an entire reaction scheme for the RSC-mediated nucleosome remodeling process that includes DNA looping, nucleosome ejection, the influence of adjacent nucleosomes, and the coordinated action between Nap1 and RSC.
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Affiliation(s)
- Kuan-Wei Hsu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Sih-Yao Chow
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Bo-Yu Su
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Yi-Han Lu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Cyuan-Ji Chen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Wen-Ling Chen
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Ming-Yuan Cheng
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan
| | - Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taiwan.
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28
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Chakraborty A, Ay F. The role of 3D genome organization in disease: From compartments to single nucleotides. Semin Cell Dev Biol 2018; 90:104-113. [PMID: 30017907 DOI: 10.1016/j.semcdb.2018.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 07/03/2018] [Indexed: 12/26/2022]
Abstract
Since the advent of the chromosome conformation capture technology, our understanding of the human genome 3D organization has grown rapidly and we now know that human interphase chromosomes are folded into multiple layers of hierarchical structures and each layer can play a critical role in transcriptional regulation. Alterations in any one of these finely-tuned layers can lead to unwanted cascade of molecular events and ultimately drive the manifestation of diseases and phenotypes. Here we discuss, starting from chromosome level organization going down to single nucleotide changes, recent studies linking diseases or phenotypes to changes in the 3D genome architecture.
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Affiliation(s)
| | - Ferhat Ay
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, USA; UC San Diego, School of Medicine, La Jolla, 92093, CA, USA.
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Top-down characterization of chicken core histones. J Proteomics 2018; 184:34-38. [PMID: 29935335 DOI: 10.1016/j.jprot.2018.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/07/2018] [Accepted: 06/14/2018] [Indexed: 12/21/2022]
Abstract
Core histones and their PTMs play important roles in regulating gene transcription and other DNA-related processes. The study of core histones PTMs, their cross-talk and functional roles is not only of broad biological significance but also of wide pathological and clinical relevance. Having the strength of comprehensive proteoform identification with 100% amino acid sequence coverage and combinatorial PTMs, top-down proteomics has become the state-of-the-art analytical tool for combinatorial PTM characterization of core histones. In this study, we report our top-down characterization of chicken (Gallus gallus domesticus) core histones, which have been widely used as models for chromosome re-construction among others because of easy availability and not-so-dense PTMs. With nanoRPLC-MS/MS analysis and ProteinGoggle database search, a total of 58 proteoforms were identified for the core histone families of H4, H2B, H2A, and H3.
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30
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Wang Q, Sun Q, Czajkowsky DM, Shao Z. Sub-kb Hi-C in D. melanogaster reveals conserved characteristics of TADs between insect and mammalian cells. Nat Commun 2018; 9:188. [PMID: 29335463 PMCID: PMC5768742 DOI: 10.1038/s41467-017-02526-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 12/06/2017] [Indexed: 01/19/2023] Open
Abstract
Topologically associating domains (TADs) are fundamental elements of the eukaryotic genomic structure. However, recent studies suggest that the insulating complexes, CTCF/cohesin, present at TAD borders in mammals are absent from those in Drosophila melanogaster, raising the possibility that border elements are not conserved among metazoans. Using in situ Hi-C with sub-kb resolution, here we show that the D. melanogaster genome is almost completely partitioned into >4000 TADs, nearly sevenfold more than previously identified. The overwhelming majority of these TADs are demarcated by the insulator complexes, BEAF-32/CP190, or BEAF-32/Chromator, indicating that these proteins may play an analogous role in flies as that of CTCF/cohesin in mammals. Moreover, extended regions previously thought to be unstructured are shown to consist of small contiguous TADs, a property also observed in mammals upon re-examination. Altogether, our work demonstrates that fundamental features associated with the higher-order folding of the genome are conserved from insects to mammals.
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Affiliation(s)
- Qi Wang
- Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Qiu Sun
- Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, 200240, Shanghai, China
| | - Daniel M Czajkowsky
- State Key Laboratory for Oncogenes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China.
| | - Zhifeng Shao
- State Key Laboratory for Oncogenes and Bio-ID Center, School of Biomedical Engineering, Shanghai Jiao Tong University, 200240, Shanghai, China.
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31
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The 10-nm chromatin fiber and its relationship to interphase chromosome organization. Biochem Soc Trans 2017; 46:67-76. [PMID: 29263138 PMCID: PMC5818668 DOI: 10.1042/bst20170101] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 01/09/2023]
Abstract
A chromosome is a single long DNA molecule assembled along its length with nucleosomes and proteins. During interphase, a mammalian chromosome exists as a highly organized supramolecular globule in the nucleus. Here, we discuss new insights into how genomic DNA is packaged and organized within interphase chromosomes. Our emphasis is on the structural principles that underlie chromosome organization, with a particular focus on the intrinsic contributions of the 10-nm chromatin fiber, but not the regular 30-nm fiber. We hypothesize that the hierarchical globular organization of an interphase chromosome is fundamentally established by the self-interacting properties of a 10-nm zig-zag array of nucleosomes, while histone post-translational modifications, histone variants, and chromatin-associated proteins serve to mold generic chromatin domains into specific structural and functional entities.
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32
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Zhuo B, Yu J, Chang L, Lei J, Wen Z, Liu C, Mao G, Wang K, Shen J, Xu X. Quantitative analysis of chromatin accessibility in mouse embryonic fibroblasts. Biochem Biophys Res Commun 2017; 493:814-820. [PMID: 28842256 DOI: 10.1016/j.bbrc.2017.08.065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 08/18/2017] [Indexed: 11/25/2022]
Abstract
Genomic DNA of eukaryotic cells is hierarchically packaged into chromatin by histones. The dynamic organization of chromatin fibers plays a critical role in the regulation of gene transcription and other DNA-associated biological processes. Recently, numerous approaches have been developed to map the chromatin organization by characterizing chromatin accessibilities in genome-wide. However, reliable methods to quantitatively map chromatin accessibility are not well-established, especially not on a genome-wide scale. Here, we developed a modified MNase-seq for mouse embryonic fibroblasts, wherein chromatin was partially digested at multiple digestion times using micrococcal nuclease (MNase), allowing quantitative analysis of local yet genome-wide chromatin compaction. Our results provide strong evidence that the chromatin accessibility at promoter regions are positively correlated with gene activity. In conclusion, our assay is an ideal tool for the quantitative study of gene regulation in the perspective of chromatin accessibility.
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Affiliation(s)
- Baowen Zhuo
- Molecular Biology Center, State Key Laboratory of Trauma, Burn, and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Juan Yu
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Luyuan Chang
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiafan Lei
- Molecular Biology Center, State Key Laboratory of Trauma, Burn, and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Zengqi Wen
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Cuifang Liu
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guankun Mao
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kehui Wang
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Shen
- National Laboratory for Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Xueqing Xu
- Molecular Biology Center, State Key Laboratory of Trauma, Burn, and Combined Injury, Daping Hospital, Third Military Medical University, Chongqing 400042, China; Central laboratory, Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen 518133, China.
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Abstract
Dynamic reshuffling of the chromatin landscape is a recurrent theme orchestrated in many, if not all, plant developmental transitions and adaptive responses. Spatiotemporal variations of the chromatin properties on regulatory genes and on structural genomic elements trigger the establishment of distinct transcriptional contexts, which in some instances can epigenetically be inherited. Studies on plant cell plasticity during the differentiation of stem cells, including gametogenesis, or the specialization of vegetative cells in various organs, as well as the investigation of allele-specific gene regulation have long been impaired by technical challenges in generating specific chromatin profiles in complex or hardly accessible cell populations. Recent advances in increasing the sensitivity of genome-enabled technologies and in the isolation of specific cell types have allowed for overcoming such limitations. These developments hint at multilevel regulatory events ranging from nucleosome accessibility and composition to higher order chromatin organization and genome topology. Uncovering the large extent to which chromatin dynamics and epigenetic processes influence gene expression is therefore not surprisingly revolutionizing current views on plant molecular genetics and (epi)genomics as well as their perspectives in eco-evolutionary biology. Here, we introduce current methodologies to probe genome-wide chromatin variations for which protocols are detailed in this book chapter, with an emphasis on the plant model species Arabidopsis.
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Histone Post-Translational Modifications and Nucleosome Organisation in Transcriptional Regulation: Some Open Questions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [PMID: 28639249 DOI: 10.1007/5584_2017_58] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The organisation of chromatin is first discussed to conclude that nucleosomes play both structural and transcription-regulatory roles. The presence of nucleosomes makes difficult the access of transcriptional factors to their target sequences and the action of RNA polymerases. The histone post-translational modifications and nucleosome remodelling are first discussed, from a historical point of view, as mechanisms to remove the obstacles imposed by chromatin structure to transcription. Instead of reviewing the state of the art of the whole field, this review is centred on some open questions. First, some "non-classical" histone modifications, such as short-chain acylations other than acetylation, are considered to conclude that their relationship with the concentration of metabolic intermediaries might make of them a sensor of the physiological state of the cells. Then attention is paid to the interest of studying chromatin organisation and epigenetic marks at a single nucleosome level as a complement to genome-wide approaches. Finally, as a consequence of the above questions, the review focuses on the presence of multiple histone post-translational modifications on a single nucleosome. The methods to detect them and their meaning, with special emphasis on bivalent marks, are discussed.
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35
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Wachsmuth M, Knoch TA, Rippe K. Dynamic properties of independent chromatin domains measured by correlation spectroscopy in living cells. Epigenetics Chromatin 2016; 9:57. [PMID: 28035241 PMCID: PMC5192577 DOI: 10.1186/s13072-016-0093-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 01/08/2023] Open
Abstract
Background Genome organization into subchromosomal topologically associating domains (TADs) is linked to cell-type-specific gene expression programs. However, dynamic properties of such domains remain elusive, and it is unclear how domain plasticity modulates genomic accessibility for soluble factors. Results Here, we combine and compare a high-resolution topology analysis of interacting chromatin loci with fluorescence correlation spectroscopy measurements of domain dynamics in single living cells. We identify topologically and dynamically independent chromatin domains of ~1 Mb in size that are best described by a loop-cluster polymer model. Hydrodynamic relaxation times and gyration radii of domains are larger for open (161 ± 15 ms, 297 ± 9 nm) than for dense chromatin (88 ± 7 ms, 243 ± 6 nm) and increase globally upon chromatin hyperacetylation or ATP depletion. Conclusions Based on the domain structure and dynamics measurements, we propose a loop-cluster model for chromatin domains. It suggests that the regulation of chromatin accessibility for soluble factors displays a significantly stronger dependence on factor concentration than search processes within a static network. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0093-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Malte Wachsmuth
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Tobias A Knoch
- Biophysical Genomics Group, Department of Cell Biology and Genetics, Erasmus Medical Center, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Karsten Rippe
- Research Group Genome Organization and Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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36
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Champroux A, Torres-Carreira J, Gharagozloo P, Drevet JR, Kocer A. Mammalian sperm nuclear organization: resiliencies and vulnerabilities. Basic Clin Androl 2016; 26:17. [PMID: 28031843 PMCID: PMC5175393 DOI: 10.1186/s12610-016-0044-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/12/2016] [Indexed: 01/07/2023] Open
Abstract
Sperm cells are remarkably complex and highly specialized compared to somatic cells. Their function is to deliver to the oocyte the paternal genomic blueprint along with a pool of proteins and RNAs so a new generation can begin. Reproductive success, including optimal embryonic development and healthy offspring, greatly depends on the integrity of the sperm chromatin structure. It is now well documented that DNA damage in sperm is linked to reproductive failures both in natural and assisted conception (Assisted Reproductive Technologies [ART]). This manuscript reviews recent important findings concerning - the unusual organization of mammalian sperm chromatin and its impact on reproductive success when modified. This review is focused on sperm chromatin damage and their impact on embryonic development and transgenerational inheritance.
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Affiliation(s)
- A. Champroux
- GReD “Genetics, Reproduction & Development” Laboratory, UMR CNRS 6293, INSERM U1103, Clermont Université, BP60026 - TSA60026, 63178 Aubière cedex, France
| | - J. Torres-Carreira
- Centro Universitário Rio Preto, UNIRP, Rodovia Br153, Km 69, CEP15093-450 São José do Rio Preto, São Paulo Brazil
| | - P. Gharagozloo
- CellOxess LLC, 830 Bear Tavern Road, Ewing, NJ 08628 USA
| | - J. R. Drevet
- GReD “Genetics, Reproduction & Development” Laboratory, UMR CNRS 6293, INSERM U1103, Clermont Université, BP60026 - TSA60026, 63178 Aubière cedex, France
| | - A. Kocer
- GReD “Genetics, Reproduction & Development” Laboratory, UMR CNRS 6293, INSERM U1103, Clermont Université, BP60026 - TSA60026, 63178 Aubière cedex, France
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Application of advanced X-ray methods in life sciences. Biochim Biophys Acta Gen Subj 2016; 1861:3671-3685. [PMID: 27156488 DOI: 10.1016/j.bbagen.2016.05.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Synchrotron radiation (SR) sources provide diverse X-ray methods for the investigation of structure-function relationships in biological macromolecules. SCOPE OF REVIEW Recent developments in SR sources and in the X-ray tools they offer for life sciences are reviewed. Specifically, advances in macromolecular crystallography, small angle X-ray solution scattering, X-ray absorption and fluorescence spectroscopy, and imaging are discussed with examples. MAJOR CONCLUSIONS SR sources offer a range of X-ray techniques that can be used in a complementary fashion in studies of biological systems at a wide range of resolutions from atomic to cellular scale. Emerging applications of X-ray techniques include the characterization of disordered proteins, noncrystalline and nonequilibrium systems, elemental imaging of tissues, cells and organs, and detection of time-resolved changes in molecular structures. GENERAL SIGNIFICANCE X-ray techniques are in the center of hybrid approaches that are used to gain insight into complex problems relating to biomolecular mechanisms, disease and possible therapeutic solutions. This article is part of a Special Issue entitled "Science for Life". Guest Editors: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo.
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38
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Maeshima K, Rogge R, Tamura S, Joti Y, Hikima T, Szerlong H, Krause C, Herman J, Seidel E, DeLuca J, Ishikawa T, Hansen JC. Nucleosomal arrays self-assemble into supramolecular globular structures lacking 30-nm fibers. EMBO J 2016; 35:1115-32. [PMID: 27072995 PMCID: PMC4868957 DOI: 10.15252/embj.201592660] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 03/08/2016] [Indexed: 11/10/2022] Open
Abstract
The existence of a 30‐nm fiber as a basic folding unit for DNA packaging has remained a topic of active discussion. Here, we characterize the supramolecular structures formed by reversible Mg2+‐dependent self‐association of linear 12‐mer nucleosomal arrays using microscopy and physicochemical approaches. These reconstituted chromatin structures, which we call “oligomers”, are globular throughout all stages of cooperative assembly and range in size from ~50 nm to a maximum diameter of ~1,000 nm. The nucleosomal arrays were packaged within the oligomers as interdigitated 10‐nm fibers, rather than folded 30‐nm structures. Linker DNA was freely accessible to micrococcal nuclease, although the oligomers remained partially intact after linker DNA digestion. The organization of chromosomal fibers in human nuclei in situ was stabilized by 1 mM MgCl2, but became disrupted in the absence of MgCl2, conditions that also dissociated the oligomers in vitro. These results indicate that a 10‐nm array of nucleosomes has the intrinsic ability to self‐assemble into large chromatin globules stabilized by nucleosome–nucleosome interactions, and suggest that the oligomers are a good in vitro model for investigating the structure and organization of interphase chromosomes.
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Affiliation(s)
- Kazuhiro Maeshima
- Biological Macromolecules Laboratory, Structural Biology Center, National Institute of Genetics and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Japan RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Japan
| | - Ryan Rogge
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Sachiko Tamura
- Biological Macromolecules Laboratory, Structural Biology Center, National Institute of Genetics and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Japan
| | - Yasumasa Joti
- RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Japan XFEL Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI), Sayo-gun, Japan
| | | | - Heather Szerlong
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Christine Krause
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Jake Herman
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Erik Seidel
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Jennifer DeLuca
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | | | - Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
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Abstract
Histones are subject to frequent combinatorial post-translational modifications (PTMs), forming a complex chemical "language" that is interpreted by PTM-specific histone-interacting protein modules (reader domains). These specific interactions are thought to instruct gene expression and downstream biological functions. While the majority of studies have focused on individual modifications, our current understanding of the combinatorial PTM patterns on histones is starting to emerge, benefiting from the convergence of multiple technologies. Here, we review the key technical advances and progress on discovery and characterization of combinatorial histone PTM patterns. We focus on the interactions between reader domains and combinatorial PTMs, which is essential for understanding the mechanism and biological meaning of establishing and interpreting information embedded in histone PTM patterns.
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Affiliation(s)
- Zhangli Su
- Department
of Biomolecular
Chemistry and the Wisconsin Institute for Discovery, University of Wisconsin—Madison, Madison, Wisconsin 53715, United States
| | - John M. Denu
- Department
of Biomolecular
Chemistry and the Wisconsin Institute for Discovery, University of Wisconsin—Madison, Madison, Wisconsin 53715, United States
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40
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Qiu Z, Elsayed Z, Peterkin V, Alkatib S, Bennett D, Landry JW. Ino80 is essential for proximal-distal axis asymmetry in part by regulating Bmp4 expression. BMC Biol 2016; 14:18. [PMID: 26975355 PMCID: PMC4790052 DOI: 10.1186/s12915-016-0238-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 02/16/2016] [Indexed: 12/12/2022] Open
Abstract
Background Understanding how embryos specify asymmetric axes is a major focus of biology. While much has been done to discover signaling pathways and transcription factors important for axis specification, comparatively little is known about how epigenetic regulators are involved. Epigenetic regulators operate downstream of signaling pathways and transcription factors to promote nuclear processes, most prominently transcription. To discover novel functions for these complexes in axis establishment during early embryonic development, we characterized phenotypes of a mouse knockout (KO) allele of the chromatin remodeling Ino80 ATPase. Results Ino80 KO embryos implant, but fail to develop beyond the egg cylinder stage. Ino80 KO embryonic stem cells (ESCs) are viable and maintain alkaline phosphatase activity, which is suggestive of pluripotency, but they fail to fully differentiate as either embryoid bodies or teratomas. Gene expression analysis of Ino80 KO early embryos by in situ hybridization and embryoid bodies by RT-PCR shows elevated Bmp4 expression and reduced expression of distal visceral endoderm (DVE) markers Cer1, Hex, and Lefty1. In culture, Bmp4 maintains stem cell pluripotency and when overexpressed is a known negative regulator of DVE differentiation in the early embryo. Consistent with the early embryo, we observed upregulated Bmp4 expression and down-regulated Cer1, Hex, and Lefty1 expression when Ino80 KO ESCs are differentiated in a monolayer. Molecular studies in these same cells demonstrate that Ino80 bound to the Bmp4 promoter regulates its chromatin structure, which correlates with enhanced SP1 binding. These results in combination suggest that Ino80 directly regulates the chromatin structure of the Bmp4 promoter with consequences to gene expression. Conclusions In contrast to Ino80 KO differentiated cells, our experiments show that undifferentiated Ino80 KO ESCs are viable, but fail to differentiate in culture and in the early embryo. Ino80 KO ESCs and the early embryo up-regulate Bmp4 expression and down-regulate the expression of DVE markers Cer1, Hex and Lefty1. Based on this data, we propose a model where the Ino80 chromatin remodeling complex represses Bmp4 expression in the early embryo, thus promoting DVE differentiation and successful proximal-distal axis establishment. These results are significant because they show that epigenetic regulators have specific roles in establishing embryonic axes. By further characterizing these complexes, we will deepen our understanding of how the mammalian embryo is patterned by epigenetic regulators. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0238-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zhijun Qiu
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Zeinab Elsayed
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Veronica Peterkin
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Suehyb Alkatib
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Dorothy Bennett
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA
| | - Joseph W Landry
- Department of Human and Molecular Genetics, Virginia Institute of Molecular Medicine, Massey Cancer Center, Virginia Commonwealth University School of Medicine, Richmond, VA, 23298, USA.
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41
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Zhu P, Li G. Structural insights of nucleosome and the 30-nm chromatin fiber. Curr Opin Struct Biol 2016; 36:106-15. [PMID: 26872330 DOI: 10.1016/j.sbi.2016.01.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/14/2016] [Accepted: 01/22/2016] [Indexed: 01/15/2023]
Abstract
The eukaryotic genome is hierarchically packaged into chromatin in the nucleus. The organization and dynamics of 30-nm chromatin fibers, which is typically regarded as the secondary structure of chromatin, play a crucial role in regulating DNA accessibility for gene expression. Here we reviewed some recent progresses on the structural studies on nucleosomes, nucleosome-protein complexes, and chromatin fibers, focusing on the structural insights how the chromatin structure is regulated by different epigenetic regulation factors.
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Affiliation(s)
- Ping Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Guohong Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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42
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Zinzalla G. A New Way Forward in Cancer Drug Discovery: Inhibiting the SWI/SNF Chromatin Remodelling Complex. Chembiochem 2016; 17:677-82. [PMID: 26684344 DOI: 10.1002/cbic.201500565] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 12/24/2022]
Abstract
Mutations in subunits of the SWI/SNF chromatin remodelling complex are found in 20 % of human cancers. At face value, this would appear to indicate that this multiprotein complex is a potent tumour suppressor. However, it has recently emerged that some mutations in the SWI/SNF complex can have a gain-of-function effect and that in other tumours, such as pancreatic cancer, leukaemia, and breast cancer, the wild-type complex is used to drive cancer. Thus, paradoxically, this "tumour suppressor" has become an attractive target for developing anticancer agents. The SWI/SNF complex makes several protein-protein interactions both within the complex and with a wide range of transcription factors, and targeting these protein-protein interactions is emerging as the best approach to modulating the activity of the complex selectively.
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Affiliation(s)
- Giovanna Zinzalla
- Microbiology, Tumour and Cell Biology (MTC), and Science for Life Laboratory (SciLifeLab), Karolinska Institutet, Tomtebodavägen 23A, Stockholm, 171 65, Sweden.
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43
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Roque A, Ponte I, Suau P. Interplay between histone H1 structure and function. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1859:444-54. [PMID: 26415976 DOI: 10.1016/j.bbagrm.2015.09.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 01/10/2023]
Abstract
H1 linker histones are involved both in the maintenance of higher-order chromatin structure and in gene regulation. Histone H1 exists in multiple isoforms, is evolutionarily variable and undergoes a large variety of post-translational modifications. We review recent progress in the understanding of the folding and structure of histone H1 domains with an emphasis on the interactions with DNA. The importance of intrinsic disorder and hydrophobic interactions in the folding and function of the carboxy-terminal domain (CTD) is discussed. The induction of a molten globule-state in the CTD by macromolecular crowding is also considered. The effects of phosphorylation by cyclin-dependent kinases on the structure of the CTD, as well as on chromatin condensation and oligomerization, are described. We also address the extranuclear functions of histone H1, including the interaction with the β-amyloid peptide.
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Affiliation(s)
- Alicia Roque
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona, Spain
| | - Inma Ponte
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona, Spain
| | - Pedro Suau
- Departamento de Bioquímica y Biología Molecular, Facultad de Biociencias, Universidad Autónoma de Barcelona, Spain.
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