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Parl FF. Analysis of CENP-B Boxes as Anchor of Kinetochores in Centromeres of Human Chromosomes. Bioinform Biol Insights 2024; 18:11779322241248913. [PMID: 38690324 PMCID: PMC11060027 DOI: 10.1177/11779322241248913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/04/2024] [Indexed: 05/02/2024] Open
Abstract
The kinetochore is a multiprotein structure that attaches at one end to DNA in the centromere and at the other end to microtubules in the mitotic spindle. By connecting centromere and spindle, the kinetochore controls the migration of chromosomes during cell division. The exact position where the kinetochore assembles on each centromere was uncertain because large sections of centromeric DNA had not been sequenced due to highly repetitive alpha-satellite arrays. Embedded in the arrays is a 17 bp consensus sequence, the so-called CENP-B box, which binds the CENP-B protein, the only protein that binds directly to centromeric DNA. Recently, the Telomere-to-Telomere Consortium published the complete centromeric DNA sequences of all chromosomes including their epigenetic modifications in the T2T-CHM13 map. I used data from the T2T-CHM13 map to locate the CENP-B boxes in the centromeres as anchor of kinetochores. Most of the CENP-B boxes in centromeric DNA are methylated with the exception of the so-called centromere dip region (CDR), where CENP-B protein dimers bind to adjacent unmethylated CENP-B boxes and interact with CENP-A and CENP-C proteins to assemble the kinetochore. The centromeres of all chromosomes combined have a size of 407 Mb of which the kinetochores account for 5.0 Mb or 1.2%. There is no correlation between centromere and kinetochore size (P = .77). While the number of CENP-B boxes varies 4-fold between chromosomes, their density (number/Kb) varies less than 2-fold with a mean of 2.61 ± 0.33. The narrow range ensures a uniform pull of the spindle on the centromeres. I illustrate the findings in a model of the human kinetochore anchored at unmethylated CENP-B boxes in the CDR and present circos plots of chromosomes to show the location of kinetochores in their respective centromeres.
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Affiliation(s)
- Fritz F Parl
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
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2
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Packiaraj J, Thakur J. DNA satellite and chromatin organization at mouse centromeres and pericentromeres. Genome Biol 2024; 25:52. [PMID: 38378611 PMCID: PMC10880262 DOI: 10.1186/s13059-024-03184-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 02/12/2024] [Indexed: 02/22/2024] Open
Abstract
BACKGROUND Centromeres are essential for faithful chromosome segregation during mitosis and meiosis. However, the organization of satellite DNA and chromatin at mouse centromeres and pericentromeres is poorly understood due to the challenges of assembling repetitive genomic regions. RESULTS Using recently available PacBio long-read sequencing data from the C57BL/6 strain, we find that contrary to the previous reports of their homogeneous nature, both centromeric minor satellites and pericentromeric major satellites exhibit a high degree of variation in sequence and organization within and between arrays. While most arrays are continuous, a significant fraction is interspersed with non-satellite sequences, including transposable elements. Using chromatin immunoprecipitation sequencing (ChIP-seq), we find that the occupancy of CENP-A and H3K9me3 chromatin at centromeric and pericentric regions, respectively, is associated with increased sequence enrichment and homogeneity at these regions. The transposable elements at centromeric regions are not part of functional centromeres as they lack significant CENP-A enrichment. Furthermore, both CENP-A and H3K9me3 nucleosomes occupy minor and major satellites spanning centromeric-pericentric junctions and a low yet significant amount of CENP-A spreads locally at centromere junctions on both pericentric and telocentric sides. Finally, while H3K9me3 nucleosomes display a well-phased organization on major satellite arrays, CENP-A nucleosomes on minor satellite arrays are poorly phased. Interestingly, the homogeneous class of major satellites also phase CENP-A and H3K27me3 nucleosomes, indicating that the nucleosome phasing is an inherent property of homogeneous major satellites. CONCLUSIONS Our findings reveal that mouse centromeres and pericentromeres display a high diversity in satellite sequence, organization, and chromatin structure.
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Affiliation(s)
- Jenika Packiaraj
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA, 30322, USA
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA, 30322, USA.
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3
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Garrett MC, Albano R, Carnwath T, Elahi L, Behrmann CA, Pemberton M, Woo D, O'Brien E, VanCauwenbergh B, Perentesis J, Shah S, Hagan M, Kendler A, Zhao C, Paranjpe A, Roskin K, Kornblum H, Plas DR, Lu QR. HDAC1 and HDAC6 are essential for driving growth in IDH1 mutant glioma. Sci Rep 2023; 13:12433. [PMID: 37528157 PMCID: PMC10394035 DOI: 10.1038/s41598-023-33889-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 04/20/2023] [Indexed: 08/03/2023] Open
Abstract
Low-grade and secondary high-grade gliomas frequently contain mutations in the IDH1 or IDH2 metabolic enzymes that are hypothesized to drive tumorigenesis by inhibiting many of the chromatin-regulating enzymes that regulate DNA structure. Histone deacetylase inhibitors are promising anti-cancer agents and have already been used in clinical trials. However, a clear understanding of their mechanism or gene targets is lacking. In this study, the authors genetically dissect patient-derived IDH1 mutant cultures to determine which HDAC enzymes drive growth in IDH1 mutant gliomas. A panel of patient-derived gliomasphere cell lines (2 IDH1 mutant lines, 3 IDH1 wildtype lines) were subjected to a drug-screen of epigenetic modifying drugs from different epigenetic classes. The effect of LBH (panobinostat) on gene expression and chromatin structure was tested on patient-derived IDH1 mutant lines. The role of each of the highly expressed HDAC enzymes was molecularly dissected using lentiviral RNA interference knock-down vectors and a patient-derived IDH1 mutant in vitro model of glioblastoma (HK252). These results were then confirmed in an in vivo xenotransplant model (BT-142). The IDH1 mutation leads to gene down-regulation, DNA hypermethylation, increased DNA accessibility and H3K27 hypo-acetylation in two distinct IDH1 mutant over-expression models. The drug screen identified histone deacetylase inhibitors (HDACi) and panobinostat (LBH) more specifically as the most selective compounds to inhibit growth in IDH1 mutant glioma lines. Of the eleven annotated HDAC enzymes (HDAC1-11) only six are expressed in IDH1 mutant glioma tissue samples and patient-derived gliomasphere lines (HDAC1-4, HDAC6, and HDAC9). Lentiviral knock-down experiments revealed that HDAC1 and HDAC6 are the most consistently essential for growth both in vitro and in vivo and target very different gene modules. Knock-down of HDAC1 or HDAC6 in vivo led to a more circumscribed less invasive tumor. The gene dysregulation induced by the IDH1 mutation is wide-spread and only partially reversible by direct IDH1 inhibition. This study identifies HDAC1 and HDAC6 as important and drug-targetable enzymes that are necessary for growth and invasiveness in IDH1 mutant gliomas.
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Affiliation(s)
- Matthew C Garrett
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA.
| | - Rebecca Albano
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Troy Carnwath
- University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Lubayna Elahi
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Catherine A Behrmann
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Merissa Pemberton
- University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Daniel Woo
- Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Eric O'Brien
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Brett VanCauwenbergh
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - John Perentesis
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Sanjit Shah
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Matthew Hagan
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ady Kendler
- Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Chuntao Zhao
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Aditi Paranjpe
- Bioinformatics Collaborative Services, Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Krishna Roskin
- Bioinformatics Collaborative Services, Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Harley Kornblum
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - David R Plas
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Q Richard Lu
- Division of Experimental Hematology and Cancer Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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4
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Packiaraj J, Thakur J. DNA satellite and chromatin organization at house mouse centromeres and pericentromeres. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.18.549612. [PMID: 37503200 PMCID: PMC10370071 DOI: 10.1101/2023.07.18.549612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Centromeres are essential for faithful chromosome segregation during mitosis and meiosis. However, the organization of satellite DNA and chromatin at mouse centromeres and pericentromeres is poorly understood due to the challenges of sequencing and assembling repetitive genomic regions. Using recently available PacBio long-read sequencing data from the C57BL/6 strain and chromatin profiling, we found that contrary to the previous reports of their highly homogeneous nature, centromeric and pericentromeric satellites display varied sequences and organization. We find that both centromeric minor satellites and pericentromeric major satellites exhibited sequence variations within and between arrays. While most arrays are continuous, a significant fraction is interspersed with non-satellite sequences, including transposable elements. Additionally, we investigated CENP-A and H3K9me3 chromatin organization at centromeres and pericentromeres using Chromatin immunoprecipitation sequencing (ChIP-seq). We found that the occupancy of CENP-A and H3K9me3 chromatin at centromeric and pericentric regions, respectively, is associated with increased sequence abundance and homogeneity at these regions. Furthermore, the transposable elements at centromeric regions are not part of functional centromeres as they lack CENP-A enrichment. Finally, we found that while H3K9me3 nucleosomes display a well-phased organization on major satellite arrays, CENP-A nucleosomes on minor satellite arrays lack phased organization. Interestingly, the homogeneous class of major satellites phase CENP-A and H3K27me3 nucleosomes as well, indicating that the nucleosome phasing is an inherent property of homogeneous major satellites. Overall, our findings reveal that house mouse centromeres and pericentromeres, which were previously thought to be highly homogenous, display significant diversity in satellite sequence, organization, and chromatin structure.
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Affiliation(s)
- Jenika Packiaraj
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA 30322
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd, Atlanta, GA 30322
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5
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Boukaba A, Wu Q, Liu J, Chen C, Liang J, Li J, Strunnikov A. Mapping separase-mediated cleavage in situ. NAR Genom Bioinform 2022; 4:lqac085. [PMID: 36415827 PMCID: PMC9673495 DOI: 10.1093/nargab/lqac085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 10/13/2022] [Accepted: 10/25/2022] [Indexed: 11/21/2022] Open
Abstract
Separase is a protease that performs critical functions in the maintenance of genetic homeostasis. Among them, the cleavage of the meiotic cohesin during meiosis is a key step in producing gametes in eukaryotes. However, the exact chromosomal localization of this proteolytic cleavage was not addressed due to the lack of experimental tools. To this end, we developed a method based on monoclonal antibodies capable of recognizing the predicted neo-epitopes produced by separase-mediated proteolysis in the RAD21 and REC8 cohesin subunits. To validate the epigenomic strategy of mapping cohesin proteolysis, anti-RAD21 neo-epitopes antibodies were used in ChIP-On-ChEPseq analysis of human cells undergoing mitotic anaphase. Second, a similar analysis applied for mapping of REC8 cleavage in germline cells in Macaque showed a correlation with a subset of alpha-satellites and other repeats, directly demonstrating that the site-specific mei-cohesin proteolysis hotspots are coincident but not identical with centromeres. The sequences for the corresponding immunoglobulin genes show a convergence of antibodies with close specificity. This approach could be potentially used to investigate cohesin ring opening events in other chromosomal locations, if applied to single cells.
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Affiliation(s)
- Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Cheng Chen
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jierong Liang
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Jingjing Li
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
| | - Alexander V Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health , Guangzhou , Guangdong , 510530 , China
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6
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Gershman A, Sauria MEG, Guitart X, Vollger MR, Hook PW, Hoyt SJ, Jain M, Shumate A, Razaghi R, Koren S, Altemose N, Caldas GV, Logsdon GA, Rhie A, Eichler EE, Schatz MC, O'Neill RJ, Phillippy AM, Miga KH, Timp W. Epigenetic patterns in a complete human genome. Science 2022; 376:eabj5089. [PMID: 35357915 PMCID: PMC9170183 DOI: 10.1126/science.abj5089] [Citation(s) in RCA: 112] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The completion of a telomere-to-telomere human reference genome, T2T-CHM13, has resolved complex regions of the genome, including repetitive and homologous regions. Here, we present a high-resolution epigenetic study of previously unresolved sequences, representing entire acrocentric chromosome short arms, gene family expansions, and a diverse collection of repeat classes. This resource precisely maps CpG methylation (32.28 million CpGs), DNA accessibility, and short-read datasets (166,058 previously unresolved chromatin immunoprecipitation sequencing peaks) to provide evidence of activity across previously unidentified or corrected genes and reveals clinically relevant paralog-specific regulation. Probing CpG methylation across human centromeres from six diverse individuals generated an estimate of variability in kinetochore localization. This analysis provides a framework with which to investigate the most elusive regions of the human genome, granting insights into epigenetic regulation.
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Affiliation(s)
- Ariel Gershman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | - Michael E G Sauria
- Department of Biology and Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Xavi Guitart
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Mitchell R Vollger
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Paul W Hook
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Savannah J Hoyt
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Miten Jain
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Alaina Shumate
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Roham Razaghi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Sergey Koren
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nicolas Altemose
- Department of Bioengineering, University of California Berkeley, Berkeley, CA, USA
| | - Gina V Caldas
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley CA, USA
| | - Glennis A Logsdon
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Michael C Schatz
- Department of Biology and Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Rachel J O'Neill
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Adam M Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Karen H Miga
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Winston Timp
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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7
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Altemose N, Glennis A, Bzikadze AV, Sidhwani P, Langley SA, Caldas GV, Hoyt SJ, Uralsky L, Ryabov FD, Shew CJ, Sauria MEG, Borchers M, Gershman A, Mikheenko A, Shepelev VA, Dvorkina T, Kunyavskaya O, Vollger MR, Rhie A, McCartney AM, Asri M, Lorig-Roach R, Shafin K, Aganezov S, Olson D, de Lima LG, Potapova T, Hartley GA, Haukness M, Kerpedjiev P, Gusev F, Tigyi K, Brooks S, Young A, Nurk S, Koren S, Salama SR, Paten B, Rogaev EI, Streets A, Karpen GH, Dernburg AF, Sullivan BA, Straight AF, Wheeler TJ, Gerton JL, Eichler EE, Phillippy AM, Timp W, Dennis MY, O'Neill RJ, Zook JM, Schatz MC, Pevzner PA, Diekhans M, Langley CH, Alexandrov IA, Miga KH. Complete genomic and epigenetic maps of human centromeres. Science 2022; 376:eabl4178. [PMID: 35357911 PMCID: PMC9233505 DOI: 10.1126/science.abl4178] [Citation(s) in RCA: 189] [Impact Index Per Article: 94.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Existing human genome assemblies have almost entirely excluded repetitive sequences within and near centromeres, limiting our understanding of their organization, evolution, and functions, which include facilitating proper chromosome segregation. Now, a complete, telomere-to-telomere human genome assembly (T2T-CHM13) has enabled us to comprehensively characterize pericentromeric and centromeric repeats, which constitute 6.2% of the genome (189.9 megabases). Detailed maps of these regions revealed multimegabase structural rearrangements, including in active centromeric repeat arrays. Analysis of centromere-associated sequences uncovered a strong relationship between the position of the centromere and the evolution of the surrounding DNA through layered repeat expansions. Furthermore, comparisons of chromosome X centromeres across a diverse panel of individuals illuminated high degrees of structural, epigenetic, and sequence variation in these complex and rapidly evolving regions.
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Affiliation(s)
- Nicolas Altemose
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - A. Glennis
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Andrey V. Bzikadze
- Graduate Program in Bioinformatics and Systems Biology, University of California San Diego, La Jolla, CA, USA
| | - Pragya Sidhwani
- Department of Biochemistry, Stanford University, Stanford, CA, USA
| | - Sasha A. Langley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Gina V. Caldas
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Savannah J. Hoyt
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Lev Uralsky
- Sirius University of Science and Technology, Sochi, Russia
- Vavilov Institute of General Genetics, Moscow, Russia
| | | | - Colin J. Shew
- Genome Center, MIND Institute, and Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA
| | | | | | - Ariel Gershman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | - Alla Mikheenko
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
| | | | - Tatiana Dvorkina
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
| | - Olga Kunyavskaya
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
| | - Mitchell R. Vollger
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ann M. McCartney
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mobin Asri
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Ryan Lorig-Roach
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Kishwar Shafin
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Sergey Aganezov
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Daniel Olson
- Department of Computer Science, University of Montana, Missoula, MT. USA
| | | | - Tamara Potapova
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Gabrielle A. Hartley
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Marina Haukness
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Fedor Gusev
- Vavilov Institute of General Genetics, Moscow, Russia
| | - Kristof Tigyi
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Shelise Brooks
- NIH Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Alice Young
- NIH Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sergey Nurk
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sergey Koren
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sofie R. Salama
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Benedict Paten
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Biomolecular Engineering, University of California Santa Cruz, CA, USA
| | - Evgeny I. Rogaev
- Sirius University of Science and Technology, Sochi, Russia
- Vavilov Institute of General Genetics, Moscow, Russia
- Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA, USA
- Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Aaron Streets
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Gary H. Karpen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- BioEngineering and BioMedical Sciences Department, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Abby F. Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA
| | - Beth A. Sullivan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | | | - Travis J. Wheeler
- Department of Computer Science, University of Montana, Missoula, MT. USA
| | - Jennifer L. Gerton
- Stowers Institute for Medical Research, Kansas City, MO, USA
- University of Kansas Medical School, Department of Biochemistry and Molecular Biology and Cancer Center, University of Kansas, Kansas City, KS, USA
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Adam M. Phillippy
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Winston Timp
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Megan Y. Dennis
- Genome Center, MIND Institute, and Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA
| | - Rachel J. O'Neill
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Justin M. Zook
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Michael C. Schatz
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Pavel A. Pevzner
- Department of Computer Science and Engineering, University of California at San Diego, San Diego, CA, USA
| | - Mark Diekhans
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Charles H. Langley
- Department of Evolution and Ecology, University of California Davis, Davis, CA, USA
| | - Ivan A. Alexandrov
- Vavilov Institute of General Genetics, Moscow, Russia
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, Saint Petersburg State University, Saint Petersburg, Russia
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Karen H. Miga
- UC Santa Cruz Genomics Institute, University of California Santa Cruz, Santa Cruz, CA, USA
- Department of Biomolecular Engineering, University of California Santa Cruz, CA, USA
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8
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Abstract
Centromeres, the chromosomal loci where spindle fibers attach during cell division to segregate chromosomes, are typically found within satellite arrays in plants and animals. Satellite arrays have been difficult to analyze because they comprise megabases of tandem head-to-tail highly repeated DNA sequences. Much evidence suggests that centromeres are epigenetically defined by the location of nucleosomes containing the centromere-specific histone H3 variant cenH3, independently of the DNA sequences where they are located; however, the reason that cenH3 nucleosomes are generally found on rapidly evolving satellite arrays has remained unclear. Recently, long-read sequencing technology has clarified the structures of satellite arrays and sparked rethinking of how they evolve, and new experiments and analyses have helped bring both understanding and further speculation about the role these highly repeated sequences play in centromere identification.
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Affiliation(s)
- Paul B Talbert
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Steven Henikoff
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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9
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Abstract
RNase H1 has become an essential tool to uncover the physiological and pathological roles of R-loops, three-stranded structures consisting of and RNA-DNA hybrid opposite to a single DNA strand (ssDNA). RNase H1 degrades the RNA portion of the R-loops returning the two DNA strands to double-stranded form (dsDNA). Overexpression of RNase H1 in different systems has helped to address the questions of where R-loops are located, their abundance, and mechanisms of formation, stability, and degradation. In this chapter we review multiple studies that used RNase H1 as an instrument to investigate R-loops multiple functions and their relevance in health and diseases.
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Affiliation(s)
- Susana M Cerritelli
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Kiran Sakhuja
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Robert J Crouch
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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10
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Hansen JC, Maeshima K, Hendzel MJ. The solid and liquid states of chromatin. Epigenetics Chromatin 2021; 14:50. [PMID: 34717733 PMCID: PMC8557566 DOI: 10.1186/s13072-021-00424-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The review begins with a concise description of the principles of phase separation. This is followed by a comprehensive section on phase separation of chromatin, in which we recount the 60 years history of chromatin aggregation studies, discuss the evidence that chromatin aggregation intrinsically is a physiologically relevant liquid-solid phase separation (LSPS) process driven by chromatin self-interaction, and highlight the recent findings that under specific solution conditions chromatin can undergo liquid-liquid phase separation (LLPS) rather than LSPS. In the next section of the review, we discuss how certain chromatin-associated proteins undergo LLPS in vitro and in vivo. Some chromatin-binding proteins undergo LLPS in purified form in near-physiological ionic strength buffers while others will do so only in the presence of DNA, nucleosomes, or chromatin. The final section of the review evaluates the solid and liquid states of chromatin in the nucleus. While chromatin behaves as an immobile solid on the mesoscale, nucleosomes are mobile on the nanoscale. We discuss how this dual nature of chromatin, which fits well the concept of viscoelasticity, contributes to genome structure, emphasizing the dominant role of chromatin self-interaction.
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Affiliation(s)
- Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Kazuhiro Maeshima
- Genome Dynamics Laboratory, National Institute of Genetics, and Department of Genetics, Sokendai (Graduate University for Advanced Studies), Mishima, Shizuoka, 411-8540, Japan.
| | - Michael J Hendzel
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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11
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Leo L, Colonna Romano N. Emerging Single-Cell Technological Approaches to Investigate Chromatin Dynamics and Centromere Regulation in Human Health and Disease. Int J Mol Sci 2021; 22:ijms22168809. [PMID: 34445507 PMCID: PMC8395756 DOI: 10.3390/ijms22168809] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 12/12/2022] Open
Abstract
Epigenetic regulators play a crucial role in establishing and maintaining gene expression states. To date, the main efforts to study cellular heterogeneity have focused on elucidating the variable nature of the chromatin landscape. Specific chromatin organisation is fundamental for normal organogenesis and developmental homeostasis and can be affected by different environmental factors. The latter can lead to detrimental alterations in gene transcription, as well as pathological conditions such as cancer. Epigenetic marks regulate the transcriptional output of cells. Centromeres are chromosome structures that are epigenetically regulated and are crucial for accurate segregation. The advent of single-cell epigenetic profiling has provided finer analytical resolution, exposing the intrinsic peculiarities of different cells within an apparently homogenous population. In this review, we discuss recent advances in methodologies applied to epigenetics, such as CUT&RUN and CUT&TAG. Then, we compare standard and emerging single-cell techniques and their relevance for investigating human diseases. Finally, we describe emerging methodologies that investigate centromeric chromatin specification and neocentromere formation.
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12
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Morrison O, Thakur J. Molecular Complexes at Euchromatin, Heterochromatin and Centromeric Chromatin. Int J Mol Sci 2021; 22:6922. [PMID: 34203193 PMCID: PMC8268097 DOI: 10.3390/ijms22136922] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023] Open
Abstract
Chromatin consists of a complex of DNA and histone proteins as its core components and plays an important role in both packaging DNA and regulating DNA metabolic pathways such as DNA replication, transcription, recombination, and chromosome segregation. Proper functioning of chromatin further involves a network of interactions among molecular complexes that modify chromatin structure and organization to affect the accessibility of DNA to transcription factors leading to the activation or repression of the transcription of target DNA loci. Based on its structure and compaction state, chromatin is categorized into euchromatin, heterochromatin, and centromeric chromatin. In this review, we discuss distinct chromatin factors and molecular complexes that constitute euchromatin-open chromatin structure associated with active transcription; heterochromatin-less accessible chromatin associated with silencing; centromeric chromatin-the site of spindle binding in chromosome segregation.
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Affiliation(s)
| | - Jitendra Thakur
- Department of Biology, Emory University, 1510 Clifton Rd #2006, Atlanta, GA 30322, USA;
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13
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Thakur J, Packiaraj J, Henikoff S. Sequence, Chromatin and Evolution of Satellite DNA. Int J Mol Sci 2021; 22:ijms22094309. [PMID: 33919233 PMCID: PMC8122249 DOI: 10.3390/ijms22094309] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/15/2022] Open
Abstract
Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protection. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embedded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.
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Affiliation(s)
- Jitendra Thakur
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
- Correspondence:
| | - Jenika Packiaraj
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Fred Hutchinson Cancer Research Center, Howard Hughes Medical Institute, Seattle, WA 98109, USA
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14
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Thakur J, Henikoff S. Architectural RNA in chromatin organization. Biochem Soc Trans 2020; 48:1967-1978. [PMID: 32897323 PMCID: PMC7609026 DOI: 10.1042/bst20191226] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022]
Abstract
RNA plays a well-established architectural role in the formation of membraneless interchromatin nuclear bodies. However, a less well-known role of RNA is in organizing chromatin, whereby specific RNAs have been found to recruit chromatin modifier proteins. Whether or not RNA can act as an architectural molecule for chromatin remains unclear, partly because dissecting the architectural role of RNA from its regulatory role remains challenging. Studies that have addressed RNA's architectural role in chromatin organization rely on in situ RNA depletion using Ribonuclease A (RNase A) and suggest that RNA plays a major direct architectural role in chromatin organization. In this review, we will discuss these findings, candidate chromatin architectural long non-coding RNAs and possible mechanisms by which RNA, along with RNA binding proteins might be mediating chromatin organization.
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Affiliation(s)
- Jitendra Thakur
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
- Howard Hughes Medical Institute, Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, U.S.A
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15
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Mitra S, Srinivasan B, Jansen LE. Stable inheritance of CENP-A chromatin: Inner strength versus dynamic control. J Cell Biol 2020; 219:e202005099. [PMID: 32931551 PMCID: PMC7659725 DOI: 10.1083/jcb.202005099] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/08/2020] [Accepted: 08/12/2020] [Indexed: 12/22/2022] Open
Abstract
Chromosome segregation during cell division is driven by mitotic spindle attachment to the centromere region on each chromosome. Centromeres form a protein scaffold defined by chromatin featuring CENP-A, a conserved histone H3 variant, in a manner largely independent of local DNA cis elements. CENP-A nucleosomes fulfill two essential criteria to epigenetically identify the centromere. They undergo self-templated duplication to reestablish centromeric chromatin following DNA replication. More importantly, CENP-A incorporated into centromeric chromatin is stably transmitted through consecutive cell division cycles. CENP-A nucleosomes have unique structural properties and binding partners that potentially explain their long lifetime in vivo. However, rather than a static building block, centromeric chromatin is dynamically regulated throughout the cell cycle, indicating that CENP-A stability is also controlled by external factors. We discuss recent insights and identify the outstanding questions on how dynamic control of the long-term stability of CENP-A ensures epigenetic centromere inheritance.
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Affiliation(s)
- Sreyoshi Mitra
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Bharath Srinivasan
- Mechanistic Biology and Profiling, Discovery Sciences, R&D, AstraZeneca, Cambridge, UK
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16
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Chromatin Profiling in Mouse Embryonic Germ Cells by CUT&RUN. Methods Mol Biol 2020. [PMID: 32944915 DOI: 10.1007/978-1-0716-0958-3_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Cleavage under targets and release using nuclease (CUT&RUN) allows the chromatin profiling of proteins of interest for which specific antibodies are available. Because it is performed on intact chromatin in situ, CUT&RUN provides exceptional signal over background, making it an ideal choice for chromatin profiling on primary cells available at limited numbers. Here, we describe its application to the profiling of histone post-translational modifications in germ cells isolated from mouse embryos from 12.5 up to 18.5 days postfertilization. This approach can be applied to as low as 100 isolated germ cells, allowing the generation of multiple genome-wide profiles from the cells obtained from a single embryo.
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17
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Klein DC, Hainer SJ. Genomic methods in profiling DNA accessibility and factor localization. Chromosome Res 2019; 28:69-85. [PMID: 31776829 PMCID: PMC7125251 DOI: 10.1007/s10577-019-09619-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022]
Abstract
Recent advancements in next-generation sequencing technologies and accompanying reductions in cost have led to an explosion of techniques to examine DNA accessibility and protein localization on chromatin genome-wide. Generally, accessible regions of chromatin are permissive for factor binding and are therefore hotspots for regulation of gene expression; conversely, genomic regions that are highly occupied by histone proteins are not permissive for factor binding and are less likely to be active regulatory regions. Identifying regions of differential accessibility can be useful to uncover putative gene regulatory regions, such as enhancers, promoters, and insulators. In addition, DNA-binding proteins, such as transcription factors that preferentially bind certain DNA sequences and histone proteins that form the core of the nucleosome, play essential roles in all DNA-templated processes. Determining the genomic localization of chromatin-bound proteins is therefore essential in determining functional roles, sequence motifs important for factor binding, and regulatory networks controlling gene expression. In this review, we discuss techniques for determining DNA accessibility and nucleosome positioning (DNase-seq, FAIRE-seq, MNase-seq, and ATAC-seq) and techniques for detecting and functionally characterizing chromatin-bound proteins (ChIP-seq, DamID, and CUT&RUN). These methods have been optimized to varying degrees of resolution, specificity, and ease of use. Here, we outline some advantages and disadvantages of these techniques, their general protocols, and a brief discussion of their development. Together, these complimentary approaches have provided an unparalleled view of chromatin architecture and functional gene regulation.
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Affiliation(s)
- David C Klein
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Sarah J Hainer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
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18
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Meers MP, Bryson TD, Henikoff JG, Henikoff S. Improved CUT&RUN chromatin profiling tools. eLife 2019; 8:e46314. [PMID: 31232687 PMCID: PMC6598765 DOI: 10.7554/elife.46314] [Citation(s) in RCA: 246] [Impact Index Per Article: 49.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/22/2019] [Indexed: 02/07/2023] Open
Abstract
Previously, we described a novel alternative to chromatin immunoprecipitation, CUT&RUN, in which unfixed permeabilized cells are incubated with antibody, followed by binding of a protein A-Micrococcal Nuclease (pA/MNase) fusion protein (Skene and Henikoff, 2017). Here we introduce three enhancements to CUT&RUN: A hybrid protein A-Protein G-MNase construct that expands antibody compatibility and simplifies purification, a modified digestion protocol that inhibits premature release of the nuclease-bound complex, and a calibration strategy based on carry-over of E. coli DNA introduced with the fusion protein. These new features, coupled with the previously described low-cost, high efficiency, high reproducibility and high-throughput capability of CUT&RUN make it the method of choice for routine epigenomic profiling.
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Affiliation(s)
- Michael P Meers
- Basic Sciences DivisionFred Hutchinson Cancer Research CenterSeattleUnited States
| | - Terri D Bryson
- Basic Sciences DivisionFred Hutchinson Cancer Research CenterSeattleUnited States
- Howard Hughes Medical InstituteUnited States
| | - Jorja G Henikoff
- Basic Sciences DivisionFred Hutchinson Cancer Research CenterSeattleUnited States
| | - Steven Henikoff
- Basic Sciences DivisionFred Hutchinson Cancer Research CenterSeattleUnited States
- Howard Hughes Medical InstituteUnited States
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19
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DNA replication acts as an error correction mechanism to maintain centromere identity by restricting CENP-A to centromeres. Nat Cell Biol 2019; 21:743-754. [PMID: 31160708 DOI: 10.1038/s41556-019-0331-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 04/18/2019] [Indexed: 12/17/2022]
Abstract
Chromatin assembled with the histone H3 variant CENP-A is the heritable epigenetic determinant of human centromere identity. Using genome-wide mapping and reference models for 23 human centromeres, CENP-A binding sites are identified within the megabase-long, repetitive α-satellite DNAs at each centromere. CENP-A is shown in early G1 to be assembled into nucleosomes within each centromere and onto 11,390 transcriptionally active sites on the chromosome arms. DNA replication is demonstrated to remove ectopically loaded, non-centromeric CENP-A. In contrast, tethering of centromeric CENP-A to the sites of DNA replication through the constitutive centromere associated network (CCAN) is shown to enable precise reloading of centromere-bound CENP-A onto the same DNA sequences as in its initial prereplication loading. Thus, DNA replication acts as an error correction mechanism for maintaining centromere identity through its removal of non-centromeric CENP-A coupled with CCAN-mediated retention and precise reloading of centromeric CENP-A.
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20
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Talbert PB, Henikoff S. Transcribing Centromeres: Noncoding RNAs and Kinetochore Assembly. Trends Genet 2018; 34:587-599. [DOI: 10.1016/j.tig.2018.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/20/2022]
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21
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McNulty SM, Sullivan BA. Alpha satellite DNA biology: finding function in the recesses of the genome. Chromosome Res 2018; 26:115-138. [PMID: 29974361 DOI: 10.1007/s10577-018-9582-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/14/2018] [Indexed: 02/05/2023]
Abstract
Repetitive DNA, formerly referred to by the misnomer "junk DNA," comprises a majority of the human genome. One class of this DNA, alpha satellite, comprises up to 10% of the genome. Alpha satellite is enriched at all human centromere regions and is competent for de novo centromere assembly. Because of the highly repetitive nature of alpha satellite, it has been difficult to achieve genome assemblies at centromeres using traditional next-generation sequencing approaches, and thus, centromeres represent gaps in the current human genome assembly. Moreover, alpha satellite DNA is transcribed into repetitive noncoding RNA and contributes to a large portion of the transcriptome. Recent efforts to characterize these transcripts and their function have uncovered pivotal roles for satellite RNA in genome stability, including silencing "selfish" DNA elements and recruiting centromere and kinetochore proteins. This review will describe the genomic and epigenetic features of alpha satellite DNA, discuss recent findings of noncoding transcripts produced from distinct alpha satellite arrays, and address current progress in the functional understanding of this oft-neglected repetitive sequence. We will discuss unique challenges of studying human satellite DNAs and RNAs and point toward new technologies that will continue to advance our understanding of this largely untapped portion of the genome.
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Affiliation(s)
- Shannon M McNulty
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Beth A Sullivan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA. .,Division of Human Genetics, Duke University Medical Center, Durham, NC, 27710, USA.
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