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Yuan T, Gao X, Xiang N, Wei P, Zhang G. The genome assembly of Carex breviculmis provides evidence for its phylogenetic localization and environmental adaptation. ANNALS OF BOTANY 2024; 134:467-484. [PMID: 38822911 PMCID: PMC11341672 DOI: 10.1093/aob/mcae085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/27/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND AND AIMS Carex breviculmis is a perennial herb with good resistance and is widely used for forage production and turf management. It is important in ecology, environmental protection and biodiversity conservation, but faces several challenges due to human activities. However, the absence of genome sequences has limited basic research and the improvement of wild plants. METHODS We annotated the genome of C. breviculmis and conducted a systematic analysis to explore its resistance to harsh environments. We also conducted a comparative analysis of Achnatherum splendens, which is similarly tolerant to harsh environments. KEY RESULTS The assembled the genome comprises 469.01 Mb, revealing 37 372 genes with a BUSCO completeness score of 99.0 %. The genome has 52.03 % repetitive sequences, primarily influenced by recent LTR insertions that have contributed to its expansion. Phylogenetic analysis suggested that C. breviculmis diverged from C. littledalei ~6.61 million years ago. Investigation of repetitive sequences and expanded gene families highlighted a rapid expansion of tandem duplicate genes, particularly in areas related to sugar metabolism, synthesis of various amino acids, and phenylpropanoid biosynthesis. Additionally, our analysis identified crucial genes involved in secondary metabolic pathways, such as glycolysis, phenylpropanoid biosynthesis and amino acid metabolism, which have undergone positive selection. We reconstructed the sucrose metabolic pathway and identified significant gene expansions, including 16 invertase, 9 sucrose phosphate synthase and 12 sucrose synthase genes associated with sucrose metabolism, which showed varying levels of expansion. CONCLUSIONS The expansion of these genes, coupled with subsequent positive selection, contributed to the ability of C. breviculmis to adapt to environmental stressors. This study lays the foundation for future research on the evolution of Carex plants, their environmental adaptations, and potential genetic breeding.
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Affiliation(s)
- Tao Yuan
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaoman Gao
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Niyan Xiang
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Pei Wei
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Guiyu Zhang
- State Key Laboratory of Hybrid Rice, Laboratory of Plant Systematics and Evolutionary Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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Santinello B, Sun R, Amjad A, Hoyt SJ, Ouyang L, Courret C, Drennan R, Leo L, Larracuente AM, Core L, O'Neill RJ, Mellone BG. Transcription of a centromere-enriched retroelement and local retention of its RNA are significant features of the CENP-A chromatin landscape. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.14.574223. [PMID: 38293134 PMCID: PMC10827089 DOI: 10.1101/2024.01.14.574223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Centromeres depend on chromatin containing the conserved histone H3 variant CENP-A for function and inheritance, while the role of centromeric DNA repeats remains unclear. Retroelements are prevalent at centromeres across taxa and represent a potential mechanism for promoting transcription to aid in CENP-A incorporation or for generating RNA transcripts to maintain centromere integrity. Here, we probe into the transcription and RNA localization of the centromere-enriched retroelement G2/Jockey-3 (hereafter referred to as Jockey-3 ) in Drosophila melanogaster , currently the only in vivo model with assembled centromeres. We find that Jockey-3 is a major component of the centromeric transcriptome and produces RNAs that localize to centromeres in metaphase. Leveraging the polymorphism of Jockey-3 and a de novo centromere system, we show that these RNAs remain associated with their cognate DNA sequences in cis , suggesting they are unlikely to perform a sequence-specific function at all centromeres. We show that Jockey-3 transcription is positively correlated with the presence of CENP-A, and that recent Jockey-3 transposition events have occurred preferentially at CENP-A-containing chromatin. We propose that Jockey-3 contributes to the epigenetic maintenance of centromeres by promoting chromatin transcription, while inserting preferentially within these regions, selfishly ensuring its continued expression and transmission. Given the conservation of retroelements as centromere components through evolution, our findings have broad implications in understanding this association in other species.
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Ramakrishnan Chandra J, Kalidass M, Demidov D, Dabravolski SA, Lermontova I. The role of centromeric repeats and transcripts in kinetochore assembly and function. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:982-996. [PMID: 37665331 DOI: 10.1111/tpj.16445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 08/09/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023]
Abstract
Centromeres are the chromosomal domains, where the kinetochore protein complex is formed, mediating proper segregation of chromosomes during cell division. Although the function of centromeres has remained conserved during evolution, centromeric DNA is highly variable, even in closely related species. In addition, the composition of the kinetochore complexes varies among organisms. Therefore, it is assumed that the centromeric position is determined epigenetically, and the centromeric histone H3 (CENH3) serves as an epigenetic marker. The loading of CENH3 onto centromeres depends on centromere-licensing factors, chaperones, and transcription of centromeric repeats. Several proteins that regulate CENH3 loading and kinetochore assembly interact with the centromeric transcripts and DNA in a sequence-independent manner. However, the functional aspects of these interactions are not fully understood. This review discusses the variability of centromeric sequences in different organisms and the regulation of their transcription through the RNA Pol II and RNAi machinery. The data suggest that the interaction of proteins involved in CENH3 loading and kinetochore assembly with centromeric DNA and transcripts plays a role in centromere, and possibly neocentromere, formation in a sequence-independent manner.
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Affiliation(s)
| | - Manikandan Kalidass
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466, Seeland, Germany
| | - Dmitri Demidov
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466, Seeland, Germany
| | - Siarhei A Dabravolski
- Department of Biotechnology Engineering, Braude Academic College of Engineering, Snunit 51, Karmiel, 2161002, Israel
| | - Inna Lermontova
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstrasse 3, D-06466, Seeland, Germany
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4
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Kalmykova AI, Sokolova OA. Retrotransposons and Telomeres. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1739-1753. [PMID: 38105195 DOI: 10.1134/s0006297923110068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/24/2023] [Accepted: 08/12/2023] [Indexed: 12/19/2023]
Abstract
Transposable elements (TEs) comprise a significant part of eukaryotic genomes being a major source of genome instability and mutagenesis. Cellular defense systems suppress the TE expansion at all stages of their life cycle. Piwi proteins and Piwi-interacting RNAs (piRNAs) are key elements of the anti-transposon defense system, which control TE activity in metazoan gonads preventing inheritable transpositions and developmental defects. In this review, we discuss various regulatory mechanisms by which small RNAs combat TE activity. However, active transposons persist, suggesting these powerful anti-transposon defense mechanisms have a limited capacity. A growing body of evidence suggests that increased TE activity coincides with genome reprogramming and telomere lengthening in different species. In the Drosophila fruit fly, whose telomeres consist only of retrotransposons, a piRNA-mediated mechanism is required for telomere maintenance and their length control. Therefore, the efficacy of protective mechanisms must be finely balanced in order not only to suppress the activity of transposons, but also to maintain the proper length and stability of telomeres. Structural and functional relationship between the telomere homeostasis and LINE1 retrotransposon in human cells indicates a close link between selfish TEs and the vital structure of the genome, telomere. This relationship, which permits the retention of active TEs in the genome, is reportedly a legacy of the retrotransposon origin of telomeres. The maintenance of telomeres and the execution of other crucial roles that TEs acquired during the process of their domestication in the genome serve as a type of payment for such a "service."
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Affiliation(s)
- Alla I Kalmykova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
| | - Olesya A Sokolova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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5
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Yang LL, Li YC, Xia TJ, Li S, Feng X, Li C, Xie FY, Ou XH, Ma JY. Dynamic of centromere associated RNAs and the centromere loading of DNA repair proteins in growing oocytes. Front Genet 2023; 14:1131698. [PMID: 37035744 PMCID: PMC10080056 DOI: 10.3389/fgene.2023.1131698] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/16/2023] [Indexed: 04/11/2023] Open
Abstract
Mammalian centromeres are generally composed of dispersed repeats and the satellites such as α-satellites in human and major/minor satellites in mouse. Transcription of centromeres by RNA polymerase II is evolutionary conserved and critical for kinetochore assembly. In addition, it has been found that the transcribed satellite RNAs can bind DNA repair proteins such as MRE11 and PRKDC, and excessively expressed satellite RNAs could induce genome instability and facilitate tumorigenesis. During the maturation of female oocyte, centromeres are critical for accurate segregation of homologous chromosomes and sister chromatids. However, the dynamics of oocyte centromere transcription and whether it associated with DNA repair proteins are unknown. In this study, we found the transcription of centromeres is active in growing oocytes but it is silenced when oocytes are fully grown. DNA repair proteins like Mlh1, Mre11 and Prkdc are found associated with the minor satellites and this association can be interfered by RNA polymerase II inhibitor α-amanitin. When the growing oocyte is in vitro matured, Mlh1/Mre11/Prkdc foci would release from centromeres to the ooplasm. If the oocytes are treated with Mre11 inhibitor Mirin, the meiosis resumption of growing oocytes with Mre11 foci can be suppressed. These data revealed the dynamic of centromeric transcription in oocytes and its potential association with DNA repair proteins, which provide clues about how oocytes maintain centromere stability and assemble kinetochores.
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Affiliation(s)
- Lin-Li Yang
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Yan-Chu Li
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Tian-Jin Xia
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Sen Li
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Xie Feng
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Chao Li
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Feng-Yun Xie
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Xiang-Hong Ou
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
- *Correspondence: Xiang-Hong Ou, ; Jun-Yu Ma,
| | - Jun-Yu Ma
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Fertilization Preservation Lab, Guangdong-Hong Kong Metabolism and Reproduction Joint Laboratory, Guangdong Second Provincial General Hospital, Guangzhou, China
- *Correspondence: Xiang-Hong Ou, ; Jun-Yu Ma,
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6
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Molecular Dynamics and Evolution of Centromeres in the Genus Equus. Int J Mol Sci 2022; 23:ijms23084183. [PMID: 35457002 PMCID: PMC9024551 DOI: 10.3390/ijms23084183] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 02/01/2023] Open
Abstract
The centromere is the chromosomal locus essential for proper chromosome segregation. While the centromeric function is well conserved and epigenetically specified, centromeric DNA sequences are typically composed of satellite DNA and represent the most rapidly evolving sequences in eukaryotic genomes. The presence of satellite sequences at centromeres hampered the comprehensive molecular analysis of these enigmatic loci. The discovery of functional centromeres completely devoid of satellite repetitions and fixed in some animal and plant species represented a turning point in centromere biology, definitively proving the epigenetic nature of the centromere. The first satellite-free centromere, fixed in a vertebrate species, was discovered in the horse. Later, an extraordinary number of satellite-free neocentromeres had been discovered in other species of the genus Equus, which remains the only mammalian genus with numerous satellite-free centromeres described thus far. These neocentromeres arose recently during evolution and are caught in a stage of incomplete maturation. Their presence made the equids a unique model for investigating, at molecular level, the minimal requirements for centromere seeding and evolution. This model system provided new insights on how centromeres are established and transmitted to the progeny and on the role of satellite DNA in different aspects of centromere biology.
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Hoyt SJ, Storer JM, Hartley GA, Grady PGS, Gershman A, de Lima LG, Limouse C, Halabian R, Wojenski L, Rodriguez M, Altemose N, Rhie A, Core LJ, Gerton JL, Makalowski W, Olson D, Rosen J, Smit AFA, Straight AF, Vollger MR, Wheeler TJ, Schatz MC, Eichler EE, Phillippy AM, Timp W, Miga KH, O’Neill RJ. From telomere to telomere: The transcriptional and epigenetic state of human repeat elements. Science 2022; 376:eabk3112. [PMID: 35357925 PMCID: PMC9301658 DOI: 10.1126/science.abk3112] [Citation(s) in RCA: 121] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mobile elements and repetitive genomic regions are sources of lineage-specific genomic innovation and uniquely fingerprint individual genomes. Comprehensive analyses of such repeat elements, including those found in more complex regions of the genome, require a complete, linear genome assembly. We present a de novo repeat discovery and annotation of the T2T-CHM13 human reference genome. We identified previously unknown satellite arrays, expanded the catalog of variants and families for repeats and mobile elements, characterized classes of complex composite repeats, and located retroelement transduction events. We detected nascent transcription and delineated CpG methylation profiles to define the structure of transcriptionally active retroelements in humans, including those in centromeres. These data expand our insight into the diversity, distribution, and evolution of repetitive regions that have shaped the human genome.
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Affiliation(s)
- Savannah J. Hoyt
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | | | - Gabrielle A. Hartley
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Patrick G. S. Grady
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Ariel Gershman
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | | | - Charles Limouse
- Department of Biochemistry, Stanford University, Stanford, CA, USA
| | - Reza Halabian
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Luke Wojenski
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Matias Rodriguez
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Nicolas Altemose
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Arang Rhie
- Genome Informatics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Leighton J. Core
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
| | | | - Wojciech Makalowski
- Institute of Bioinformatics, Faculty of Medicine, University of Münster, Münster, Germany
| | - Daniel Olson
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Jeb Rosen
- Institute for Systems Biology, Seattle, WA, USA
| | | | | | - Mitchell R. Vollger
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA, USA
| | - Travis J. Wheeler
- Department of Computer Science, University of Montana, Missoula, MT, USA
| | - Michael C. Schatz
- Department of Computer Science and Department of Biology, Johns Hopkins University, Baltimore, 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
| | - 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
| | - Karen H. Miga
- UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Rachel J. O’Neill
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA
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8
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Niu Y, Teng X, Zhou H, Shi Y, Li Y, Tang Y, Zhang P, Luo H, Kang Q, Xu T, He S. Characterizing mobile element insertions in 5675 genomes. Nucleic Acids Res 2022; 50:2493-2508. [PMID: 35212372 PMCID: PMC8934628 DOI: 10.1093/nar/gkac128] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 12/30/2022] Open
Abstract
Mobile element insertions (MEIs) are a major class of structural variants (SVs) and have been linked to many human genetic disorders, including hemophilia, neurofibromatosis, and various cancers. However, human MEI resources from large-scale genome sequencing are still lacking compared to those for SNPs and SVs. Here, we report a comprehensive map of 36 699 non-reference MEIs constructed from 5675 genomes, comprising 2998 Chinese samples (∼26.2×, NyuWa) and 2677 samples from the 1000 Genomes Project (∼7.4×, 1KGP). We discovered that LINE-1 insertions were highly enriched in centromere regions, implying the role of chromosome context in retroelement insertion. After functional annotation, we estimated that MEIs are responsible for about 9.3% of all protein-truncating events per genome. Finally, we built a companion database named HMEID for public use. This resource represents the latest and largest genomewide study on MEIs and will have broad utility for exploration of human MEI findings.
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Affiliation(s)
- Yiwei Niu
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xueyi Teng
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Honghong Zhou
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yirong Shi
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanyan Li
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiheng Tang
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Zhang
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Huaxia Luo
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Quan Kang
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Tao Xu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shunmin He
- Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Abstract
The centromere performs a universally conserved function, to accurately partition genetic information upon cell division. Yet, centromeres are among the most rapidly evolving regions of the genome and are bound by a varying assortment of centromere-binding factors that are themselves highly divergent at the protein-sequence level. A common thread in most species is the dependence on the centromere-specific histone variant CENP-A for the specification of the centromere site. However, CENP-A is not universally required in all species or cell types, making the identification of a general mechanism for centromere specification challenging. In this review, we examine our current understanding of the mechanisms of centromere specification in CENP-A-dependent and independent systems, focusing primarily on recent work.
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Affiliation(s)
- Barbara G Mellone
- Department of Molecular and Cell Biology, and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA.
| | - Daniele Fachinetti
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005 Paris, France.
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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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11
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Vondrak T, Oliveira L, Novák P, Koblížková A, Neumann P, Macas J. Complex sequence organization of heterochromatin in the holocentric plant Cuscuta europaea elucidated by the computational analysis of nanopore reads. Comput Struct Biotechnol J 2021; 19:2179-2189. [PMID: 33995911 PMCID: PMC8091179 DOI: 10.1016/j.csbj.2021.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/31/2021] [Accepted: 04/03/2021] [Indexed: 12/20/2022] Open
Abstract
Repeat-rich regions of higher plant genomes are usually associated with constitutive heterochromatin, a specific type of chromatin that forms tightly packed nuclear chromocenters and chromosome bands. There is a large body of cytogenetic evidence that these chromosome regions are often composed of tandemly organized satellite DNA. However, comparatively little is known about the sequence arrangement within heterochromatic regions, which are difficult to assemble due to their repeated nature. Here, we explore long-range sequence organization of heterochromatin regions containing the major satellite repeat CUS-TR24 in the holocentric plant Cuscuta europaea. Using a combination of ultra-long read sequencing with assembly-free sequence analysis, we reveal the complex structure of these loci, which are composed of short arrays of CUS-TR24 interrupted frequently by emerging simple sequence repeats and targeted insertions of a specific lineage of LINE retrotransposons. These data suggest that the organization of satellite repeats constituting heterochromatic chromosome bands can be more complex than previously envisioned, and demonstrate that heterochromatin organization can be efficiently investigated without the need for genome assembly.
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Affiliation(s)
- Tihana Vondrak
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
- University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic
| | - Ludmila Oliveira
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
| | - Petr Novák
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
| | - Andrea Koblížková
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
| | - Pavel Neumann
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
| | - Jiří Macas
- Biology Centre, Czech Academy of Sciences, Institute of Plant Molecular Biology, Branišovská 31, České Budějovice CZ-37005, Czech Republic
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12
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Murillo-Pineda M, Valente LP, Dumont M, Mata JF, Fachinetti D, Jansen LE. Induction of spontaneous human neocentromere formation and long-term maturation. J Cell Biol 2021; 220:e202007210. [PMID: 33443568 PMCID: PMC7812830 DOI: 10.1083/jcb.202007210] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/23/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
Human centromeres form primarily on α-satellite DNA but sporadically arise de novo at naive ectopic loci, creating neocentromeres. Centromere inheritance is driven primarily by chromatin containing the histone H3 variant CENP-A. Here, we report a chromosome engineering system for neocentromere formation in human cells and characterize the first experimentally induced human neocentromere at a naive locus. The spontaneously formed neocentromere spans a gene-poor 100-kb domain enriched in histone H3 lysine 9 trimethylated (H3K9me3). Long-read sequencing revealed this neocentromere was formed by purely epigenetic means and assembly of a functional kinetochore correlated with CENP-A seeding, eviction of H3K9me3 and local accumulation of mitotic cohesin and RNA polymerase II. At formation, the young neocentromere showed markedly reduced chromosomal passenger complex (CPC) occupancy and poor sister chromatin cohesion. However, long-term tracking revealed increased CPC assembly and low-level transcription providing evidence for centromere maturation over time.
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Affiliation(s)
- Marina Murillo-Pineda
- Department of Biochemistry, University of Oxford, Oxford, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | | | - Marie Dumont
- Institut Curie, Paris Sciences et Lettres, Research University, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 144, Paris, France
| | - João F. Mata
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Daniele Fachinetti
- Institut Curie, Paris Sciences et Lettres, Research University, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 144, Paris, France
| | - Lars E.T. Jansen
- Department of Biochemistry, University of Oxford, Oxford, UK
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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13
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Emerging roles of centromeric RNAs in centromere formation and function. Genes Genomics 2021; 43:217-226. [PMID: 33523401 DOI: 10.1007/s13258-021-01041-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 01/04/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Centromeres are specialized chromosomal domains involved in kinetochore formation and faithful chromosome segregation. Despite a high level of functional conservation, centromeres are not identified by DNA sequences, but by epigenetic means. Universally, centromeres are typically formed on highly repetitive DNA, which were previously considered to be silent. However, recent studies have shown that transcription occurs in this region, known as centromeric-derived RNAs (cenRNAs). CenRNAs that contribute to fundamental aspects of centromere function have been recently investigated in detail. However, the distribution, behavior and contributions of centromeric transcripts are still poorly understood. OBJECTIVE The aim of this article is to provide an overview of the roles of cenRNAs in centromere formation and function. METHODS We describe the structure and DNA sequence of centromere from yeast to human. In addition, we briefly introduce the roles of cenRNAs in centromere formation and function, kinetochore structure, accurate chromosome segregation, and pericentromeric heterochromatin assembly. Centromeric circular RNAs (circRNAs) and R-loops are rising stars in centromere function. CircRNAs have been successfully identified in various species with the assistance of high-throughput sequencing and novel computational approaches for non-polyadenylated RNA transcripts. Centromeric R-loops can be identified by the single-strand DNA ligation-based library preparation technique. But the molecular features and function of these centromeric R-loops and circRNAs are still being investigated. CONCLUSION In this review, we summarize recent findings on the epigenetic regulation of cenRNAs across species, which would provide useful information about cenRNAs and interesting hints for further studies.
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14
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Mihìc P, Hédouin S, Francastel C. Centromeres Transcription and Transcripts for Better and for Worse. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 60:169-201. [PMID: 34386876 DOI: 10.1007/978-3-030-74889-0_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Centromeres are chromosomal regions that are essential for the faithful transmission of genetic material through each cell division. They represent the chromosomal platform on which assembles a protein complex, the kinetochore, which mediates attachment to the mitotic spindle. In most organisms, centromeres assemble on large arrays of tandem satellite repeats, although their DNA sequences and organization are highly divergent among species. It has become evident that centromeres are not defined by underlying DNA sequences, but are instead epigenetically defined by the deposition of the centromere-specific histone H3 variant, CENP-A. In addition, and although long regarded as silent chromosomal loci, centromeres are in fact transcriptionally competent in most species, yet at low levels in normal somatic cells, but where the resulting transcripts participate in centromere architecture, identity, and function. In this chapter, we discuss the various roles proposed for centromere transcription and their transcripts, and the potential molecular mechanisms involved. We also discuss pathological cases in which unscheduled transcription of centromeric repeats or aberrant accumulation of their transcripts are pathological signatures of chromosomal instability diseases. In sum, tight regulation of centromeric satellite repeats transcription is critical for healthy development and tissue homeostasis, and thus prevents the emergence of disease states.
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Affiliation(s)
- Pia Mihìc
- Université De Paris, Epigenetics and Cell Fate, CNRS UMR7216, Paris, France
| | - Sabrine Hédouin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Claire Francastel
- Université De Paris, Epigenetics and Cell Fate, CNRS UMR7216, Paris, France.
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15
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Ellison CE, Kagda MS, Cao W. Telomeric TART elements target the piRNA machinery in Drosophila. PLoS Biol 2020; 18:e3000689. [PMID: 33347429 PMCID: PMC7785250 DOI: 10.1371/journal.pbio.3000689] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 01/05/2021] [Accepted: 12/10/2020] [Indexed: 11/23/2022] Open
Abstract
Coevolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres but has also reportedly inserted into the Drosophila melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that TART-A produces abundant Piwi-interacting small RNAs (piRNAs), some of which are antisense to the nxf2 transcript, and that the TART-like region of nxf2 is evolving rapidly. Furthermore, in D. melanogaster, TART-A is present at higher copy numbers, and nxf2 shows reduced expression, compared to the closely related species Drosophila simulans. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these 2 elements are engaged in antagonistic coevolution despite the fact that TART-A is serving a critical role for its host genome. Co-evolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by re-establishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. This study shows that a specialized Drosophila retrotransposon that functions as a telomere has captured a portion of a host piRNA gene which may allow it to evade silencing.
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Affiliation(s)
- Christopher E. Ellison
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Meenakshi S. Kagda
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Weihuan Cao
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
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16
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Bury L, Moodie B, Ly J, McKay LS, Miga KH, Cheeseman IM. Alpha-satellite RNA transcripts are repressed by centromere-nucleolus associations. eLife 2020; 9:59770. [PMID: 33174837 PMCID: PMC7679138 DOI: 10.7554/elife.59770] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 11/09/2020] [Indexed: 01/03/2023] Open
Abstract
Although originally thought to be silent chromosomal regions, centromeres are instead actively transcribed. However, the behavior and contributions of centromere-derived RNAs have remained unclear. Here, we used single-molecule fluorescence in-situ hybridization (smFISH) to detect alpha-satellite RNA transcripts in intact human cells. We find that alpha-satellite RNA-smFISH foci levels vary across cell lines and over the cell cycle, but do not remain associated with centromeres, displaying localization consistent with other long non-coding RNAs. Alpha-satellite expression occurs through RNA polymerase II-dependent transcription, but does not require established centromere or cell division components. Instead, our work implicates centromere–nucleolar interactions as repressing alpha-satellite expression. The fraction of nucleolar-localized centromeres inversely correlates with alpha-satellite transcripts levels across cell lines and transcript levels increase substantially when the nucleolus is disrupted. The control of alpha-satellite transcripts by centromere-nucleolar contacts provides a mechanism to modulate centromere transcription and chromatin dynamics across diverse cell states and conditions.
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Affiliation(s)
- Leah Bury
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Brittania Moodie
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Jimmy Ly
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Liliana S McKay
- Whitehead Institute for Biomedical Research, Cambridge, United States
| | - Karen Hh Miga
- UC Santa Cruz Genomics Institute, University of California, Santa Cruz, Santa Cruz, United States
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, Cambridge, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
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17
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Tolmacheva EN, Vasilyev SA, Lebedev IN. Aneuploidy and DNA Methylation as Mirrored Features of Early Human Embryo Development. Genes (Basel) 2020; 11:E1084. [PMID: 32957536 PMCID: PMC7564410 DOI: 10.3390/genes11091084] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
Genome stability is an integral feature of all living organisms. Aneuploidy is the most common cause of fetal death in humans. The timing of bursts in increased aneuploidy frequency coincides with the waves of global epigenetic reprogramming in mammals. During gametogenesis and early embryogenesis, parental genomes undergo two waves of DNA methylation reprogramming. Failure of these processes can critically affect genome stability, including chromosome segregation during cell division. Abnormal methylation due to errors in the reprogramming process can potentially lead to aneuploidy. On the other hand, the presence of an entire additional chromosome, or chromosome loss, can affect the global genome methylation level. The associations of these two phenomena are well studied in the context of carcinogenesis, but here, we consider the relationship of DNA methylation and aneuploidy in early human and mammalian ontogenesis. In this review, we link these two phenomena and highlight the critical ontogenesis periods and genome regions that play a significant role in human reproduction and in the formation of pathological phenotypes in newborns with chromosomal aneuploidy.
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Affiliation(s)
- Ekaterina N. Tolmacheva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, 634050 Tomsk, Russia; (S.A.V.); (I.N.L.)
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18
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Arunkumar G, Melters DP. Centromeric Transcription: A Conserved Swiss-Army Knife. Genes (Basel) 2020; 11:E911. [PMID: 32784923 PMCID: PMC7463856 DOI: 10.3390/genes11080911] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
In most species, the centromere is comprised of repetitive DNA sequences, which rapidly evolve. Paradoxically, centromeres fulfill an essential function during mitosis, as they are the chromosomal sites wherein, through the kinetochore, the mitotic spindles bind. It is now generally accepted that centromeres are transcribed, and that such transcription is associated with a broad range of functions. More than a decade of work on this topic has shown that centromeric transcripts are found across the eukaryotic tree and associate with heterochromatin formation, chromatin structure, kinetochore structure, centromeric protein loading, and inner centromere signaling. In this review, we discuss the conservation of small and long non-coding centromeric RNAs, their associations with various centromeric functions, and their potential roles in disease.
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Affiliation(s)
| | - Daniël P. Melters
- Chromatin Structure and Epigenetic Mechanisms, Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA;
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19
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Leo L, Marchetti M, Giunta S, Fanti L. Epigenetics as an Evolutionary Tool for Centromere Flexibility. Genes (Basel) 2020; 11:genes11070809. [PMID: 32708654 PMCID: PMC7397245 DOI: 10.3390/genes11070809] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/11/2020] [Accepted: 07/13/2020] [Indexed: 12/31/2022] Open
Abstract
Centromeres are the complex structures responsible for the proper segregation of chromosomes during cell division. Structural or functional alterations of the centromere cause aneuploidies and other chromosomal aberrations that can induce cell death with consequences on health and survival of the organism as a whole. Because of their essential function in the cell, centromeres have evolved high flexibility and mechanisms of tolerance to preserve their function following stress, whether it is originating from within or outside the cell. Here, we review the main epigenetic mechanisms of centromeres’ adaptability to preserve their functional stability, with particular reference to neocentromeres and holocentromeres. The centromere position can shift in response to altered chromosome structures, but how and why neocentromeres appear in a given chromosome region are still open questions. Models of neocentromere formation developed during the last few years will be hereby discussed. Moreover, we will discuss the evolutionary significance of diffuse centromeres (holocentromeres) in organisms such as nematodes. Despite the differences in DNA sequences, protein composition and centromere size, all of these diverse centromere structures promote efficient chromosome segregation, balancing genome stability and adaptability, and ensuring faithful genome inheritance at each cellular generation.
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Affiliation(s)
- Laura Leo
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie “Charles Darwin”, “Sapienza” University of Rome, 00185 Rome, Italy; (L.L.); (M.M.); (S.G.)
| | - Marcella Marchetti
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie “Charles Darwin”, “Sapienza” University of Rome, 00185 Rome, Italy; (L.L.); (M.M.); (S.G.)
| | - Simona Giunta
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie “Charles Darwin”, “Sapienza” University of Rome, 00185 Rome, Italy; (L.L.); (M.M.); (S.G.)
- Laboratory of Chromosome and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Laura Fanti
- Istituto Pasteur Italia, Dipartimento di Biologia e Biotecnologie “Charles Darwin”, “Sapienza” University of Rome, 00185 Rome, Italy; (L.L.); (M.M.); (S.G.)
- Correspondence:
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20
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Wong CYY, Ling YH, Mak JKH, Zhu J, Yuen KWY. "Lessons from the extremes: Epigenetic and genetic regulation in point monocentromere and holocentromere establishment on artificial chromosomes". Exp Cell Res 2020; 390:111974. [PMID: 32222413 DOI: 10.1016/j.yexcr.2020.111974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 02/08/2023]
Abstract
The formation of de novo centromeres on artificial chromosomes in humans (HACs) and fission yeast (SpYACs) has provided much insights to the epigenetic and genetic control on regional centromere establishment and maintenance. Similarly, the use of artificial chromosomes in point centromeric budding yeast Saccharomyces cerevisiae (ScYACs) and holocentric Caenorhabditis elegans (WACs) has revealed epigenetic regulation in the originally thought purely genetically-determined point centromeres and some centromeric DNA sequence features in holocentromeres, respectively. These relatively extreme and less characterized centromere organizations, on the endogenous chromosomes and artificial chromosomes, will be discussed and compared to the more well-studied regional centromere systems. This review will highlight some of the common epigenetic and genetic features in different centromere architectures, including the presence of the centromeric histone H3 variant, CENP-A or CenH3, centromeric and pericentric transcription, AT-richness and repetitiveness of centromeric DNA sequences.
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Affiliation(s)
- Charmaine Yan Yu Wong
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yick Hin Ling
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jason Ka Ho Mak
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jing Zhu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Karen Wing Yee Yuen
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong.
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21
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Ito KK, Watanabe K, Kitagawa D. The Emerging Role of ncRNAs and RNA-Binding Proteins in Mitotic Apparatus Formation. Noncoding RNA 2020; 6:E13. [PMID: 32245090 PMCID: PMC7151635 DOI: 10.3390/ncrna6010013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 12/14/2022] Open
Abstract
Mounting experimental evidence shows that non-coding RNAs (ncRNAs) serve a wide variety of biological functions. Recent studies suggest that a part of ncRNAs are critically important for supporting the structure of subcellular architectures. Here, we summarize the current literature demonstrating the role of ncRNAs and RNA-binding proteins in regulating the assembly of mitotic apparatus, especially focusing on centrosomes, kinetochores, and mitotic spindles.
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Affiliation(s)
| | | | - Daiju Kitagawa
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Science, The University of Tokyo, Bunkyo, Tokyo 113-0033, Japan; (K.K.I.); (K.W.)
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22
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Singh PP, Shukla M, White SA, Lafos M, Tong P, Auchynnikava T, Spanos C, Rappsilber J, Pidoux AL, Allshire RC. Hap2-Ino80-facilitated transcription promotes de novo establishment of CENP-A chromatin. Genes Dev 2020; 34:226-238. [PMID: 31919190 PMCID: PMC7000912 DOI: 10.1101/gad.332536.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
Abstract
Centromeres are maintained epigenetically by the presence of CENP-A, an evolutionarily conserved histone H3 variant, which directs kinetochore assembly and hence centromere function. To identify factors that promote assembly of CENP-A chromatin, we affinity-selected solubilized fission yeast CENP-ACnp1 chromatin. All subunits of the Ino80 complex were enriched, including the auxiliary subunit Hap2. Chromatin association of Hap2 is Ies4-dependent. In addition to a role in maintenance of CENP-ACnp1 chromatin integrity at endogenous centromeres, Hap2 is required for de novo assembly of CENP-ACnp1 chromatin on naïve centromere DNA and promotes H3 turnover on centromere regions and other loci prone to CENP-ACnp1 deposition. Prior to CENP-ACnp1 chromatin assembly, Hap2 facilitates transcription from centromere DNA. These analyses suggest that Hap2-Ino80 destabilizes H3 nucleosomes on centromere DNA through transcription-coupled histone H3 turnover, driving the replacement of resident H3 nucleosomes with CENP-ACnp1 nucleosomes. These inherent properties define centromere DNA by directing a program that mediates CENP-ACnp1 assembly on appropriate sequences.
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Affiliation(s)
- Puneet P. Singh
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Manu Shukla
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Sharon A. White
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Marcel Lafos
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Pin Tong
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Tatsiana Auchynnikava
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Christos Spanos
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Juri Rappsilber
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom;,Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
| | - Alison L. Pidoux
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Robin C. Allshire
- Wellcome Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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23
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Liu Y, Su H, Zhang J, Liu Y, Feng C, Han F. Back-spliced RNA from retrotransposon binds to centromere and regulates centromeric chromatin loops in maize. PLoS Biol 2020. [PMID: 31995554 DOI: 10.1371/journal.pbio.3000582.g006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
In most plants, centromeric DNA contains highly repetitive sequences, including tandem repeats and retrotransposons; however, the roles of these sequences in the structure and function of the centromere are unclear. Here, we found that multiple RNA sequences from centromeric retrotransposons (CRMs) were enriched in maize (Zea mays) centromeres, and back-spliced RNAs were generated from CRM1. We identified 3 types of CRM1-derived circular RNAs with the same back-splicing site based on the back-spliced sequences. These circular RNAs bound to the centromere through R-loops. Two R-loop sites inside a single circular RNA promoted the formation of chromatin loops in CRM1 regions. When RNA interference (RNAi) was used to target the back-splicing site of the circular CRM1 RNAs, the levels of R-loops and chromatin loops formed by these circular RNAs decreased, while the levels of R-loops produced by linear RNAs with similar binding sites increased. Linear RNAs with only one R-loop site could not promote chromatin loop formation. Higher levels of R-loops and lower levels of chromatin loops in the CRM1 regions of RNAi plants led to a reduced localization of the centromeric H3 variant (CENH3). Our work reveals centromeric chromatin organization by circular CRM1 RNAs via R-loops and chromatin loops, which suggested that CRM1 elements might help build a suitable chromatin environment during centromere evolution. These results highlight that R-loops are integral components of centromeric chromatin and proper centromere structure is essential for CENH3 localization.
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Affiliation(s)
- Yalin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chao Feng
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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24
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Achrem M, Szućko I, Kalinka A. The epigenetic regulation of centromeres and telomeres in plants and animals. COMPARATIVE CYTOGENETICS 2020; 14:265-311. [PMID: 32733650 PMCID: PMC7360632 DOI: 10.3897/compcytogen.v14i2.51895] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/18/2020] [Indexed: 05/10/2023]
Abstract
The centromere is a chromosomal region where the kinetochore is formed, which is the attachment point of spindle fibers. Thus, it is responsible for the correct chromosome segregation during cell division. Telomeres protect chromosome ends against enzymatic degradation and fusions, and localize chromosomes in the cell nucleus. For this reason, centromeres and telomeres are parts of each linear chromosome that are necessary for their proper functioning. More and more research results show that the identity and functions of these chromosomal regions are epigenetically determined. Telomeres and centromeres are both usually described as highly condensed heterochromatin regions. However, the epigenetic nature of centromeres and telomeres is unique, as epigenetic modifications characteristic of both eu- and heterochromatin have been found in these areas. This specificity allows for the proper functioning of both regions, thereby affecting chromosome homeostasis. This review focuses on demonstrating the role of epigenetic mechanisms in the functioning of centromeres and telomeres in plants and animals.
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Affiliation(s)
- Magdalena Achrem
- Institute of Biology, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
| | - Izabela Szućko
- Institute of Biology, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
| | - Anna Kalinka
- Institute of Biology, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
- Molecular Biology and Biotechnology Center, University of Szczecin, Szczecin, PolandUniversity of SzczecinSzczecinPoland
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Liu Y, Su H, Zhang J, Liu Y, Feng C, Han F. Back-spliced RNA from retrotransposon binds to centromere and regulates centromeric chromatin loops in maize. PLoS Biol 2020; 18:e3000582. [PMID: 31995554 PMCID: PMC7010299 DOI: 10.1371/journal.pbio.3000582] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 02/10/2020] [Accepted: 01/03/2020] [Indexed: 12/14/2022] Open
Abstract
In most plants, centromeric DNA contains highly repetitive sequences, including tandem repeats and retrotransposons; however, the roles of these sequences in the structure and function of the centromere are unclear. Here, we found that multiple RNA sequences from centromeric retrotransposons (CRMs) were enriched in maize (Zea mays) centromeres, and back-spliced RNAs were generated from CRM1. We identified 3 types of CRM1-derived circular RNAs with the same back-splicing site based on the back-spliced sequences. These circular RNAs bound to the centromere through R-loops. Two R-loop sites inside a single circular RNA promoted the formation of chromatin loops in CRM1 regions. When RNA interference (RNAi) was used to target the back-splicing site of the circular CRM1 RNAs, the levels of R-loops and chromatin loops formed by these circular RNAs decreased, while the levels of R-loops produced by linear RNAs with similar binding sites increased. Linear RNAs with only one R-loop site could not promote chromatin loop formation. Higher levels of R-loops and lower levels of chromatin loops in the CRM1 regions of RNAi plants led to a reduced localization of the centromeric H3 variant (CENH3). Our work reveals centromeric chromatin organization by circular CRM1 RNAs via R-loops and chromatin loops, which suggested that CRM1 elements might help build a suitable chromatin environment during centromere evolution. These results highlight that R-loops are integral components of centromeric chromatin and proper centromere structure is essential for CENH3 localization.
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Affiliation(s)
- Yalin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chao Feng
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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26
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Navarro-Mendoza MI, Pérez-Arques C, Panchal S, Nicolás FE, Mondo SJ, Ganguly P, Pangilinan J, Grigoriev IV, Heitman J, Sanyal K, Garre V. Early Diverging Fungus Mucor circinelloides Lacks Centromeric Histone CENP-A and Displays a Mosaic of Point and Regional Centromeres. Curr Biol 2019; 29:3791-3802.e6. [PMID: 31679929 PMCID: PMC6925572 DOI: 10.1016/j.cub.2019.09.024] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/06/2019] [Accepted: 09/10/2019] [Indexed: 12/20/2022]
Abstract
Centromeres are rapidly evolving across eukaryotes, despite performing a conserved function to ensure high-fidelity chromosome segregation. CENP-A chromatin is a hallmark of a functional centromere in most organisms. Due to its critical role in kinetochore architecture, the loss of CENP-A is tolerated in only a few organisms, many of which possess holocentric chromosomes. Here, we characterize the consequence of the loss of CENP-A in the fungal kingdom. Mucor circinelloides, an opportunistic human pathogen, lacks CENP-A along with the evolutionarily conserved CENP-C but assembles a monocentric chromosome with a localized kinetochore complex throughout the cell cycle. Mis12 and Dsn1, two conserved kinetochore proteins, were found to co-localize to a short region, one in each of nine large scaffolds, composed of an ∼200-bp AT-rich sequence followed by a centromere-specific conserved motif that echoes the structure of budding yeast point centromeres. Resembling fungal regional centromeres, these core centromere regions are embedded in large genomic expanses devoid of genes yet marked by Grem-LINE1s, a novel retrotransposable element silenced by the Dicer-dependent RNAi pathway. Our results suggest that these hybrid features of point and regional centromeres arose from the absence of CENP-A, thus defining novel mosaic centromeres in this early-diverging fungus.
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Affiliation(s)
| | - Carlos Pérez-Arques
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain
| | - Shweta Panchal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Francisco E Nicolás
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain
| | - Stephen J Mondo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA; Bioagricultural Science and Pest Management Department, Colorado State University, Fort Collins, CO 80521, USA
| | - Promit Ganguly
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Jasmyn Pangilinan
- US Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Igor V Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94598, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Kaustuv Sanyal
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
| | - Victoriano Garre
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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Duda Z, Trusiak S, O'Neill R. Centromere Transcription: Means and Motive. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2019; 56:257-281. [PMID: 28840241 DOI: 10.1007/978-3-319-58592-5_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The chromosome biology field at large has benefited from studies of the cell cycle components, protein cascades and genomic landscape that are required for centromere identity, assembly and stable transgenerational inheritance. Research over the past 20 years has challenged the classical descriptions of a centromere as a stable, unmutable, and transcriptionally silent chromosome component. Instead, based on studies from a broad range of eukaryotic species, including yeast, fungi, plants, and animals, the centromere has been redefined as one of the more dynamic areas of the eukaryotic genome, requiring coordination of protein complex assembly, chromatin assembly, and transcriptional activity in a cell cycle specific manner. What has emerged from more recent studies is the realization that the transcription of specific types of nucleic acids is a key process in defining centromere integrity and function. To illustrate the transcriptional landscape of centromeres across eukaryotes, we focus this review on how transcripts interact with centromere proteins, when in the cell cycle centromeric transcription occurs, and what types of sequences are being transcribed. Utilizing data from broadly different organisms, a picture emerges that places centromeric transcription as an integral component of centromere function.
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Affiliation(s)
- Zachary Duda
- Department of Molecular and Cell Biology, The Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA
| | - Sarah Trusiak
- Department of Molecular and Cell Biology, The Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA
| | - Rachel O'Neill
- Department of Molecular and Cell Biology, The Institute for Systems Genomics, University of Connecticut, Storrs, CT, 06269, USA.
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28
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Chang CH, Chavan A, Palladino J, Wei X, Martins NMC, Santinello B, Chen CC, Erceg J, Beliveau BJ, Wu CT, Larracuente AM, Mellone BG. Islands of retroelements are major components of Drosophila centromeres. PLoS Biol 2019; 17:e3000241. [PMID: 31086362 PMCID: PMC6516634 DOI: 10.1371/journal.pbio.3000241] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/08/2019] [Indexed: 12/24/2022] Open
Abstract
Centromeres are essential chromosomal regions that mediate kinetochore assembly and spindle attachments during cell division. Despite their functional conservation, centromeres are among the most rapidly evolving genomic regions and can shape karyotype evolution and speciation across taxa. Although significant progress has been made in identifying centromere-associated proteins, the highly repetitive centromeres of metazoans have been refractory to DNA sequencing and assembly, leaving large gaps in our understanding of their functional organization and evolution. Here, we identify the sequence composition and organization of the centromeres of Drosophila melanogaster by combining long-read sequencing, chromatin immunoprecipitation for the centromeric histone CENP-A, and high-resolution chromatin fiber imaging. Contrary to previous models that heralded satellite repeats as the major functional components, we demonstrate that functional centromeres form on islands of complex DNA sequences enriched in retroelements that are flanked by large arrays of satellite repeats. Each centromere displays distinct size and arrangement of its DNA elements but is similar in composition overall. We discover that a specific retroelement, G2/Jockey-3, is the most highly enriched sequence in CENP-A chromatin and is the only element shared among all centromeres. G2/Jockey-3 is also associated with CENP-A in the sister species D. simulans, revealing an unexpected conservation despite the reported turnover of centromeric satellite DNA. Our work reveals the DNA sequence identity of the active centromeres of a premier model organism and implicates retroelements as conserved features of centromeric DNA.
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Affiliation(s)
- Ching-Ho Chang
- Department of Biology, University of Rochester; Rochester, New York, United States of America
| | - Ankita Chavan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Jason Palladino
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Xiaolu Wei
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Nuno M. C. Martins
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bryce Santinello
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Chin-Chi Chen
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
| | - Jelena Erceg
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brian J. Beliveau
- Wyss Institute for Biologically Inspired Engineering, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Genome Sciences, University of Washington Seattle, Seattle, Washington, United States of America
| | - Chao-Ting Wu
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Amanda M. Larracuente
- Department of Biology, University of Rochester; Rochester, New York, United States of America
| | - Barbara G. Mellone
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, United States of America
- Institute for Systems Genomics, University of Connecticut Storrs, Connecticut, United States of America
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29
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Centromere Repeats: Hidden Gems of the Genome. Genes (Basel) 2019; 10:genes10030223. [PMID: 30884847 PMCID: PMC6471113 DOI: 10.3390/genes10030223] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/07/2019] [Accepted: 03/11/2019] [Indexed: 01/08/2023] Open
Abstract
Satellite DNAs are now regarded as powerful and active contributors to genomic and chromosomal evolution. Paired with mobile transposable elements, these repetitive sequences provide a dynamic mechanism through which novel karyotypic modifications and chromosomal rearrangements may occur. In this review, we discuss the regulatory activity of satellite DNA and their neighboring transposable elements in a chromosomal context with a particular emphasis on the integral role of both in centromere function. In addition, we discuss the varied mechanisms by which centromeric repeats have endured evolutionary processes, producing a novel, species-specific centromeric landscape despite sharing a ubiquitously conserved function. Finally, we highlight the role these repetitive elements play in the establishment and functionality of de novo centromeres and chromosomal breakpoints that underpin karyotypic variation. By emphasizing these unique activities of satellite DNAs and transposable elements, we hope to disparage the conventional exemplification of repetitive DNA in the historically-associated context of ‘junk’.
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30
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Profiling of LINE-1-Related Genes in Hepatocellular Carcinoma. Int J Mol Sci 2019; 20:ijms20030645. [PMID: 30717368 PMCID: PMC6387036 DOI: 10.3390/ijms20030645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/26/2019] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a prime public health concern that accounts for most of the primary liver malignancies in humans. The most common etiological factor of HCC is hepatitis B virus (HBV). Despite recent advances in treatment strategies, there has been little success in improving the survival of HCC patients. To develop a novel therapeutic approach, evaluation of a working hypothesis based on different viewpoints might be important. Long interspersed element 1 (L1) retrotransposons have been suggested to play a role in HCC. However, the molecular machineries that can modulate L1 biology in HBV-related HCC have not been well-evaluated. Here, we summarize the profiles of expression and/or activation status of L1-related genes in HBV-related HCC, and HBV- and HCC-related genes that may impact L1-mediated tumorigenesis. L1 restriction factors appear to be suppressed by HBV infection. Since some of the L1 restriction factors also limit HBV, these factors may be exhausted in HBV-infected cells, which causes de-suppression of L1. Several HBV- and HCC-related genes that interact with L1 can affect oncogenic processes. Thus, L1 may be a novel prime therapeutic target for HBV-related HCC. Studies in this area will provide insights into HCC and other types of cancers.
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31
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Smurova K, De Wulf P. Centromere and Pericentromere Transcription: Roles and Regulation … in Sickness and in Health. Front Genet 2018; 9:674. [PMID: 30627137 PMCID: PMC6309819 DOI: 10.3389/fgene.2018.00674] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/04/2018] [Indexed: 12/26/2022] Open
Abstract
The chromosomal loci known as centromeres (CEN) mediate the equal distribution of the duplicated genome between both daughter cells. Specifically, centromeres recruit a protein complex named the kinetochore, that bi-orients the replicated chromosome pairs to the mitotic or meiotic spindle structure. The paired chromosomes are then separated, and the individual chromosomes segregate in opposite direction along the regressing spindle into each daughter cell. Erroneous kinetochore assembly or activity produces aneuploid cells that contain an abnormal number of chromosomes. Aneuploidy may incite cell death, developmental defects (including genetic syndromes), and cancer (>90% of all cancer cells are aneuploid). While kinetochores and their activities have been preserved through evolution, the CEN DNA sequences have not. Hence, to be recognized as sites for kinetochore assembly, CEN display conserved structural themes. In addition, CEN nucleosomes enclose a CEN-exclusive variant of histone H3, named CENP-A, and carry distinct epigenetic labels on CENP-A and the other CEN histone proteins. Through the cell cycle, CEN are transcribed into non-coding RNAs. After subsequent processing, they become key components of the CEN chromatin by marking the CEN locus and by stably anchoring the CEN-binding kinetochore proteins. CEN transcription is tightly regulated, of low intensity, and essential for differentiation and development. Under- or overexpression of CEN transcripts, as documented for myriad cancers, provoke chromosome missegregation and aneuploidy. CEN are genetically stable and fully competent only when they are insulated from the surrounding, pericentromeric chromatin, which must be silenced. We will review CEN transcription and its contribution to faithful kinetochore function. We will further discuss how pericentromeric chromatin is silenced by RNA processing and transcriptionally repressive chromatin marks. We will report on the transcriptional misregulation of (peri)centromeres during stress, natural aging, and disease and reflect on whether their transcripts can serve as future diagnostic tools and anti-cancer targets in the clinic.
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Affiliation(s)
- Ksenia Smurova
- Centre for Integrative Biology, University of Trento, Trento, Italy
| | - Peter De Wulf
- Centre for Integrative Biology, University of Trento, Trento, Italy
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32
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Barra V, Fachinetti D. The dark side of centromeres: types, causes and consequences of structural abnormalities implicating centromeric DNA. Nat Commun 2018; 9:4340. [PMID: 30337534 PMCID: PMC6194107 DOI: 10.1038/s41467-018-06545-y] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/06/2018] [Indexed: 12/18/2022] Open
Abstract
Centromeres are the chromosomal domains required to ensure faithful transmission of the genome during cell division. They have a central role in preventing aneuploidy, by orchestrating the assembly of several components required for chromosome separation. However, centromeres also adopt a complex structure that makes them susceptible to being sites of chromosome rearrangements. Therefore, preservation of centromere integrity is a difficult, but important task for the cell. In this review, we discuss how centromeres could potentially be a source of genome instability and how centromere aberrations and rearrangements are linked with human diseases such as cancer.
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Affiliation(s)
- V Barra
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France
| | - D Fachinetti
- Institut Curie, PSL Research University, CNRS, UMR 144, 26 rue d'Ulm, F-75005, Paris, France.
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33
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The Behavior of the Maize B Chromosome and Centromere. Genes (Basel) 2018; 9:genes9100476. [PMID: 30275397 PMCID: PMC6210970 DOI: 10.3390/genes9100476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 09/16/2018] [Accepted: 09/25/2018] [Indexed: 12/15/2022] Open
Abstract
The maize B chromosome is a non-essential chromosome with an accumulation mechanism. The dispensable nature of the B chromosome facilitates many types of genetic studies in maize. Maize lines with B chromosomes have been widely used in studies of centromere functions. Here, we discuss the maize B chromosome alongside the latest progress of B centromere activities, including centromere misdivision, inactivation, reactivation, and de novo centromere formation. The meiotic features of the B centromere, related to mini-chromosomes and the control of the size of the maize centromere, are also discussed.
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34
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Abstract
Accurate chromosome segregation is a fundamental process in cell biology. During mitosis, chromosomes are segregated into daughter cells through interactions between centromeres and microtubules in the mitotic spindle. Centromere domains have evolved to nucleate formation of the kinetochore, which is essential for establishing connections between chromosomal DNA and microtubules during mitosis. Centromeres are typically formed on highly repetitive DNA that is not conserved in sequence or size among organisms and can differ substantially between individuals within the same organism. However, transcription of repetitive DNA has emerged as a highly conserved property of the centromere. Recent work has shown that both the topological effect of transcription on chromatin and the nascent noncoding RNAs contribute to multiple aspects of centromere function. In this review, we discuss the fundamental aspects of centromere transcription, i.e., its dual role in chromatin remodeling/CENP-A deposition and kinetochore assembly during mitosis, from a cell cycle perspective.
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Affiliation(s)
- Carlos Perea-Resa
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael D Blower
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
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35
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Nergadze SG, Piras FM, Gamba R, Corbo M, Cerutti F, McCarter JGW, Cappelletti E, Gozzo F, Harman RM, Antczak DF, Miller D, Scharfe M, Pavesi G, Raimondi E, Sullivan KF, Giulotto E. Birth, evolution, and transmission of satellite-free mammalian centromeric domains. Genome Res 2018; 28:789-799. [PMID: 29712753 PMCID: PMC5991519 DOI: 10.1101/gr.231159.117] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 04/13/2018] [Indexed: 11/25/2022]
Abstract
Mammalian centromeres are associated with highly repetitive DNA (satellite DNA), which has so far hindered molecular analysis of this chromatin domain. Centromeres are epigenetically specified, and binding of the CENPA protein is their main determinant. In previous work, we described the first example of a natural satellite-free centromere on Equus caballus Chromosome 11. Here, we investigated the satellite-free centromeres of Equus asinus by using ChIP-seq with anti-CENPA antibodies. We identified an extraordinarily high number of centromeres lacking satellite DNA (16 of 31). All of them lay in LINE- and AT-rich regions. A subset of these centromeres is associated with DNA amplification. The location of CENPA binding domains can vary in different individuals, giving rise to epialleles. The analysis of epiallele transmission in hybrids (three mules and one hinny) showed that centromeric domains are inherited as Mendelian traits, but their position can slide in one generation. Conversely, centromere location is stable during mitotic propagation of cultured cells. Our results demonstrate that the presence of more than half of centromeres void of satellite DNA is compatible with genome stability and species survival. The presence of amplified DNA at some centromeres suggests that these arrays may represent an intermediate stage toward satellite DNA formation during evolution. The fact that CENPA binding domains can move within relatively restricted regions (a few hundred kilobases) suggests that the centromeric function is physically limited by epigenetic boundaries.
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Affiliation(s)
- Solomon G Nergadze
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Francesca M Piras
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Riccardo Gamba
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Marco Corbo
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Federico Cerutti
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Joseph G W McCarter
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, H91 TK33, Ireland
| | - Eleonora Cappelletti
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Francesco Gozzo
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Rebecca M Harman
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14850, USA
| | - Douglas F Antczak
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14850, USA
| | - Donald Miller
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14850, USA
| | - Maren Scharfe
- Genomanalytik (GMAK), Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
| | - Giulio Pavesi
- Department of Biosciences, University of Milano, 20122 Milano, Italy
| | - Elena Raimondi
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
| | - Kevin F Sullivan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, H91 TK33, Ireland
| | - Elena Giulotto
- Department of Biology and Biotechnology "Lazzaro Spallanzani," University of Pavia, 27100 Pavia, Italy
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36
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Ostromyshenskii DI, Chernyaeva EN, Kuznetsova IS, Podgornaya OI. Mouse chromocenters DNA content: sequencing and in silico analysis. BMC Genomics 2018; 19:151. [PMID: 29458329 PMCID: PMC5819297 DOI: 10.1186/s12864-018-4534-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 02/06/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chromocenters are defined as a punctate condensed blocks of chromatin in the interphase cell nuclei of certain cell types with unknown biological significance. In recent years a progress in revealing of chromocenters protein content has been made although the details of DNA content within constitutive heterochromatin still remain unclear. It is known that these regions are enriched in tandem repeats (TR) and transposable elements. Quick improvement of genome sequencing does not help to assemble the heterochromatic regions due to lack of appropriate bioinformatics techniques. RESULTS Chromocenters DNA have been isolated by a biochemical approach from mouse liver cells nuclei and sequenced on the Illumina MiSeq resulting in ChrmC dataset. Analysis of ChrmC dataset by the bioinformatics tools available revealed that the major component of chromocenter DNA are TRs: ~ 66% MaSat and ~ 4% MiSat. Other previously classified TR families constitute ~ 1% of ChrmC dataset. About 6% of chromocenters DNA are mostly unannotated sequences. In the contigs assembled with IDBA_UD there are many fragments of heterochromatic Y-chromosome, rDNA and other pseudo-genes and non-coding DNA. A protein coding sfi1 homolog gene fragment was also found in contigs. The Sfi1 homolog gene is located on the chromosome 11 in the reference genome very close to the Golden Pass Gap (a ~ 3 Mb empty region reserved to the pericentromeric region) and proves the purity of chromocenters isolation. The second major fraction are non-LTR retroposons (SINE and LINE) with overwhelming majority of LINE - ~ 11% of ChrmC. Most of the LINE fragments are from the ~ 2 kb region at the end of the 2nd ORF and its' flanking region. The precise LINEs' segment of ~ 2 kb is the necessary mouse constitutive heterohromatin component together with TR. The third most abundant fraction are ERVs. The ERV distribution in chromocenters differs from the whole genome: IAP (ERV2 class) is the most numerous in ChrmC while MaLR (ERV3 class) prevails in the reference genome. IAP and its LTR also prevail in TR containing contigs extracted from the WGS dataset. In silico prediction of IAP and LINE fragments in chromocenters was confirmed by direct fluorescent in situ hybridization (FISH). CONCLUSION Our data of chromocenters' DNA (ChrmC) sequencing demonstrate that IAP with LTR and a precise ~ 2 kb fragment of LINE represent a substantial fraction of mouse chromocenters (constitutive heteroсhromatin) along with TRs.
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Affiliation(s)
- Dmitrii I Ostromyshenskii
- Institute of Cytology RAS, St.-Petersburg, 194064, Russia.
- Far Eastern Federal University, Vladivostok, 690922, Russia.
| | | | - Inna S Kuznetsova
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Olga I Podgornaya
- Institute of Cytology RAS, St.-Petersburg, 194064, Russia
- Far Eastern Federal University, Vladivostok, 690922, Russia
- St Petersburg State University, St Petersburg, 199034, Russia
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Klein SJ, O'Neill RJ. Transposable elements: genome innovation, chromosome diversity, and centromere conflict. Chromosome Res 2018; 26:5-23. [PMID: 29332159 PMCID: PMC5857280 DOI: 10.1007/s10577-017-9569-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 12/21/2022]
Abstract
Although it was nearly 70 years ago when transposable elements (TEs) were first discovered “jumping” from one genomic location to another, TEs are now recognized as contributors to genomic innovations as well as genome instability across a wide variety of species. In this review, we illustrate the ways in which active TEs, specifically retroelements, can create novel chromosome rearrangements and impact gene expression, leading to disease in some cases and species-specific diversity in others. We explore the ways in which eukaryotic genomes have evolved defense mechanisms to temper TE activity and the ways in which TEs continue to influence genome structure despite being rendered transpositionally inactive. Finally, we focus on the role of TEs in the establishment, maintenance, and stabilization of critical, yet rapidly evolving, chromosome features: eukaryotic centromeres. Across centromeres, specific types of TEs participate in genomic conflict, a balancing act wherein they are actively inserting into centromeric domains yet are harnessed for the recruitment of centromeric histones and potentially new centromere formation.
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Affiliation(s)
- Savannah J Klein
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Rachel J O'Neill
- Institute for Systems Genomics and Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, 06269, USA.
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38
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Hernández-Saavedra D, Strakovsky RS, Ostrosky-Wegman P, Pan YX. Epigenetic Regulation of Centromere Chromatin Stability by Dietary and Environmental Factors. Adv Nutr 2017; 8:889-904. [PMID: 29141972 PMCID: PMC5683002 DOI: 10.3945/an.117.016402] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The centromere is a genomic locus required for the segregation of the chromosomes during cell division. This chromosomal region together with pericentromeres has been found to be susceptible to damage, and thus the perturbation of the centromere could lead to the development of aneuploidic events. Metabolic abnormalities that underlie the generation of cancer include inflammation, oxidative stress, cell cycle deregulation, and numerous others. The micronucleus assay, an early clinical marker of cancer, has been shown to provide a reliable measure of genotoxic damage that may signal cancer initiation. In the current review, we will discuss the events that lead to micronucleus formation and centromeric and pericentromeric chromatin instability, as well transcripts emanating from these regions, which were previously thought to be inactive. Studies were selected in PubMed if they reported the effects of nutritional status (macro- and micronutrients) or environmental toxicant exposure on micronucleus frequency or any other chromosomal abnormality in humans, animals, or cell models. Mounting evidence from epidemiologic, environmental, and nutritional studies provides a novel perspective on the origination of aneuploidic events. Although substantial evidence exists describing the role that nutritional status and environmental toxicants have on the generation of micronuclei and other nuclear aberrations, limited information is available to describe the importance of macro- and micronutrients on centromeric and pericentromeric chromatin stability. Moving forward, studies that specifically address the direct link between nutritional status, excess, or deficiency and the epigenetic regulation of the centromere will provide much needed insight into the nutritional and environmental regulation of this chromosomal region and the initiation of aneuploidy.
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Affiliation(s)
| | | | | | - Yuan-Xiang Pan
- Division of Nutritional Sciences,,Department of Food Science and Human Nutrition,,Illinois Informatics Institute, University of Illinois at Urbana-Champaign, Champaign, IL; and
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Chüeh AC, Liew MS, Russell PA, Walkiewicz M, Jayachandran A, Starmans MH, Boutros PC, Wright G, Barnett SA, Mariadason JM, John T. Promoter hypomethylation of NY-ESO-1, association with clinicopathological features and PD-L1 expression in non-small cell lung cancer. Oncotarget 2017; 8:74036-74048. [PMID: 29088766 PMCID: PMC5650321 DOI: 10.18632/oncotarget.18198] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022] Open
Abstract
Cancer-Testis antigens (CTA) are immunogenic molecules with normal tissue expression restricted to testes but with aberrant expression in up to 30% of non-small cell lung cancers (NSCLCs). Regulation of CTA expression is mediated in part through promoter DNA methylation. Recently, immunotherapy has altered treatment paradigms in NSCLC. Given its immunogenicity and ability to be re-expressed through demethylation, NY-ESO-1 promoter methylation, protein expression and its association with programmed death receptor ligand-1 (PD-L1) expression and clinicopathological features were investigated. Lung cancer cell line demethylation resulting from 5-Aza-2'-deoxycytidine treatment was associated with both NY-ESO-1 and PD-L1 re-expression in vitro but not increased chemosensitivity. NY-ESO-1 hypomethylation was observed in 15/94 (16%) of patient samples and associated with positive protein expression (P < 0.0001). In contrast, PD-L1 expression was observed in 50/91 (55%) but strong expression in only 12/91 (13%) cases. There was no association between NY-ESO-1 and PD-L1 expression, despite resultant re-expression of both by 5-Aza-2'-deoxycytidine. Importantly, NY-ESO-1 hypomethylation was found to be an independent marker of poor prognosis in patients not treated with chemotherapy (HR 3.59, P = 0.003) in multivariate analysis. In patients treated with chemotherapy there were no differences in survival associated with NY-ESO-1 hypomethylation. Collectively, these results provided supporting evidence for the potential use of NY-ESO-1 hypomethylation as a prognostic biomarker in stage 3 NSCLCs. In addition, these data highlight the potential to incorporate demethylating agents to enhance immune activation, in tumours currently devoid of immune infiltrates and expression of immune checkpoint genes.
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Affiliation(s)
- Anderly C. Chüeh
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 2 Department of Medicine, Austin Health, University of Melbourne, Victoria, Australia
| | - Mun-Sem Liew
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 2 Department of Medicine, Austin Health, University of Melbourne, Victoria, Australia
- 3 Olivia Newton-John Cancer Research Institute, Victoria, Australia
| | - Prudence A. Russell
- 4 Department of Anatomical Pathology, St Vincent’s Hospital, Victoria, Australia
| | - Marzena Walkiewicz
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 3 Olivia Newton-John Cancer Research Institute, Victoria, Australia
| | - Aparna Jayachandran
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 3 Olivia Newton-John Cancer Research Institute, Victoria, Australia
- 5 School of Cancer Medicine, La Trobe University, Victoria, Australia
| | - Maud H.W. Starmans
- 6 Informatics and Biocomputing Program, Ontario Institute for Cancer Research, Toronto, Canada
| | - Paul C. Boutros
- 6 Informatics and Biocomputing Program, Ontario Institute for Cancer Research, Toronto, Canada
- 7 Department of Medical Biophysics, University of Toronto, Toronto, Canada
- 8 Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada
| | - Gavin Wright
- 9 Department of Thoracic Oncology, St Vincent’s Hospital, Victoria, Australia
| | - Stephen A Barnett
- 10 Department of Thoracic Surgery, Austin Hospital, Melbourne, Victoria, Australia
| | - John M. Mariadason
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 2 Department of Medicine, Austin Health, University of Melbourne, Victoria, Australia
- 3 Olivia Newton-John Cancer Research Institute, Victoria, Australia
- 5 School of Cancer Medicine, La Trobe University, Victoria, Australia
| | - Thomas John
- 1 Ludwig Institute of Cancer Research, Melbourne-Austin Branch, Victoria, Australia
- 2 Department of Medicine, Austin Health, University of Melbourne, Victoria, Australia
- 3 Olivia Newton-John Cancer Research Institute, Victoria, Australia
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40
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Advani G, Lim YC, Catimel B, Lio DSS, Ng NLY, Chüeh AC, Tran M, Anasir MI, Verkade H, Zhu HJ, Turk BE, Smithgall TE, Ang CS, Griffin M, Cheng HC. Csk-homologous kinase (Chk) is an efficient inhibitor of Src-family kinases but a poor catalyst of phosphorylation of their C-terminal regulatory tyrosine. Cell Commun Signal 2017; 15:29. [PMID: 28784162 PMCID: PMC5547543 DOI: 10.1186/s12964-017-0186-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 07/28/2017] [Indexed: 11/10/2022] Open
Abstract
Background C-terminal Src kinase (Csk) and Csk-homologous kinase (Chk) are the major endogenous inhibitors of Src-family kinases (SFKs). They employ two mechanisms to inhibit SFKs. First, they phosphorylate the C-terminal tail tyrosine which stabilizes SFKs in a closed inactive conformation by engaging the SH2 domain in cis. Second, they employ a non-catalytic inhibitory mechanism involving direct binding of Csk and Chk to the active forms of SFKs that is independent of phosphorylation of their C-terminal tail. Csk and Chk are co-expressed in many cell types. Contributions of the two mechanisms towards the inhibitory activity of Csk and Chk are not fully clear. Furthermore, the determinants in Csk and Chk governing their inhibition of SFKs by the non-catalytic inhibitory mechanism are yet to be defined. Methods We determined the contributions of the two mechanisms towards the inhibitory activity of Csk and Chk both in vitro and in transduced colorectal cancer cells. Specifically, we assayed the catalytic activities of Csk and Chk in phosphorylating a specific peptide substrate and a recombinant SFK member Src. We employed surface plasmon resonance spectroscopy to measure the kinetic parameters of binding of Csk, Chk and their mutants to a constitutively active mutant of the SFK member Hck. Finally, we determined the effects of expression of recombinant Chk on anchorage-independent growth and SFK catalytic activity in Chk-deficient colorectal cancer cells. Results Our results revealed Csk as a robust enzyme catalysing phosphorylation of the C-terminal tail tyrosine of SFKs but a weak non-catalytic inhibitor of SFKs. In contrast, Chk is a poor catalyst of SFK tail phosphorylation but binds SFKs with high affinity, enabling it to efficiently inhibit SFKs with the non-catalytic inhibitory mechanism both in vitro and in transduced colorectal cancer cells. Further analyses mapped some of the determinants governing this non-catalytic inhibitory mechanism of Chk to its kinase domain. Conclusions SFKs are activated by different upstream signals to adopt multiple active conformations in cells. SFKs adopting these conformations can effectively be constrained by the two complementary inhibitory mechanisms of Csk and Chk. Furthermore, the lack of this non-catalytic inhibitory mechanism accounts for SFK overactivation in the Chk-deficient colorectal cancer cells. Electronic supplementary material The online version of this article (doi:10.1186/s12964-017-0186-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gahana Advani
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, School of Biomedical Sciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Ya Chee Lim
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,PAP Rashidah Sa'adatul Bolkiah Institute of Health Sciences, Universiti Brunei Darussalam, Gadong, Brunei Darussalam
| | - Bruno Catimel
- Walter and Eliza Hall Institute for Medical Research and Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Daisy Sio Seng Lio
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, School of Biomedical Sciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Nadia L Y Ng
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, School of Biomedical Sciences, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Anderly C Chüeh
- Walter and Eliza Hall Institute for Medical Research and Department of Medical Biology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Mai Tran
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Mohd Ishtiaq Anasir
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Heather Verkade
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hong-Jian Zhu
- Department of Surgery, University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, 3052, Australia
| | - Benjamin E Turk
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Thomas E Smithgall
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ching-Seng Ang
- Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Michael Griffin
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Heung-Chin Cheng
- Department of Biochemistry & Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia. .,Bio21 Biotechnology and Molecular Science Institute, University of Melbourne, Parkville, VIC, 3010, Australia. .,Cell Signalling Research Laboratories, School of Biomedical Sciences, University of Melbourne, Parkville, VIC, 3010, Australia.
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Schalch T, Steiner FA. Structure of centromere chromatin: from nucleosome to chromosomal architecture. Chromosoma 2017; 126:443-455. [PMID: 27858158 PMCID: PMC5509776 DOI: 10.1007/s00412-016-0620-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/09/2016] [Accepted: 11/10/2016] [Indexed: 12/14/2022]
Abstract
The centromere is essential for the segregation of chromosomes, as it serves as attachment site for microtubules to mediate chromosome segregation during mitosis and meiosis. In most organisms, the centromere is restricted to one chromosomal region that appears as primary constriction on the condensed chromosome and is partitioned into two chromatin domains: The centromere core is characterized by the centromere-specific histone H3 variant CENP-A (also called cenH3) and is required for specifying the centromere and for building the kinetochore complex during mitosis. This core region is generally flanked by pericentric heterochromatin, characterized by nucleosomes containing H3 methylated on lysine 9 (H3K9me) that are bound by heterochromatin proteins. During mitosis, these two domains together form a three-dimensional structure that exposes CENP-A-containing chromatin to the surface for interaction with the kinetochore and microtubules. At the same time, this structure supports the tension generated during the segregation of sister chromatids to opposite poles. In this review, we discuss recent insight into the characteristics of the centromere, from the specialized chromatin structures at the centromere core and the pericentromere to the three-dimensional organization of these regions that make up the functional centromere.
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Affiliation(s)
- Thomas Schalch
- Department of Molecular Biology, Sciences III, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
| | - Florian A Steiner
- Department of Molecular Biology, Sciences III, Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
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42
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Wang J, Liu Y, Su H, Guo X, Han F. Centromere structure and function analysis in wheat-rye translocation lines. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:199-207. [PMID: 28370580 DOI: 10.1111/tpj.13554] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 03/19/2017] [Accepted: 03/23/2017] [Indexed: 05/12/2023]
Abstract
1RS.1BL translocations are centric translocations formed by misdivision and have been used extensively in wheat breeding. However, the role that the centromere plays in the formation of 1RS.1BL translocations is still unclear. Fluorescence in situ hybridization (FISH) was applied to detect the fine structures of the centromeres in 130 1RS.1BL translocation cultivars. Immuno-FISH, chromatin immunoprecipitation (ChIP)-qPCR and RT-PCR were used to investigate the functions of the hybrid centromeres in 1RS.1BL translocations. New 1R translocations with different centromere structures were created by misdivision and pollen irradiation to elucidate the role that the centromere plays in the formation of 1RS.1BL translocations. We found that all of the 1RS.1BL translocations detected contained hybrid centromeres and that wheat-derived CENH3 bound to both the wheat and rye centromeres in the 1RS.1BL translocation chromosomes. Moreover, a rye centromere-specific retrotransposon was actively transcribed in 1RS.1BL translocations. The frequencies of new 1RS hybrid centromere translocations and group-1 chromosome translocations were higher during 1R misdivision. Our study demonstrates the hybrid nature of the centromere in 1RS.1BL translocations. New 1R translocations with different centromere structures were created to help understand the fusion centromere used for wheat breeding and for use as breeding material for the improvement of wheat.
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Affiliation(s)
- Jing Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yalin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xianrui Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
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43
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Differential chromosomal organization between Saguinus midas and Saguinus bicolor with accumulation of differences the repetitive sequence DNA. Genetica 2017. [PMID: 28634866 DOI: 10.1007/s10709-017-9971-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Saguinus is the largest and most complex genus of the subfamily Callitrichinae, with 23 species distributed from the south of Central America to the north of South America with Saguinus midas having the largest geographical distribution while Saguinus bicolor has a very restricted one, affected by the population expansion in the state of Amazonas. Considering the phylogenetic proximity of the two species along with evidence on the existence of hybrids between them, as well as cytogenetic studies on Saguinus describing a conserved karyotypic macrostructure, we carried out a physical mapping of DNA repeated sequences in the mitotic chromosome of both species, since these sequences are less susceptible to evolutionary pressure and possibly perform an important function in speciation. Both species presented 2n = 46 chromosomes; in S. midas, chromosome Y is the smallest. Multiple ribosomal sites occur in both species, but chromosome pairs three and four may be regarded as markers that differ the species when subjected to G banding and distribution of retroelement LINE 1, suggesting that it may be cytogenetic marker in which it can contribute to identification of first generation hybrids in contact zone. Saguinus bicolor also presented differences in the LINE 1 distribution pattern for sexual chromosome X in individuals from different urban fragments, probably due to geographical isolation. In this context, cytogenetic analyses reveal a differential genomic organization pattern between species S. midas and S. bicolor, in addition to indicating that individuals from different urban fragments have been accumulating differences because of the isolation between them.
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44
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Chen CC, Mellone BG. Chromatin assembly: Journey to the CENter of the chromosome. J Cell Biol 2017; 214:13-24. [PMID: 27377247 PMCID: PMC4932374 DOI: 10.1083/jcb.201605005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/14/2016] [Indexed: 11/22/2022] Open
Abstract
All eukaryotic genomes are packaged into basic units of DNA wrapped around histone proteins called nucleosomes. The ability of histones to specify a variety of epigenetic states at defined chromatin domains is essential for cell survival. The most distinctive type of chromatin is found at centromeres, which are marked by the centromere-specific histone H3 variant CENP-A. Many of the factors that regulate CENP-A chromatin have been identified; however, our understanding of the mechanisms of centromeric nucleosome assembly, maintenance, and reorganization remains limited. This review discusses recent insights into these processes and draws parallels between centromeric and noncentromeric chromatin assembly mechanisms.
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Affiliation(s)
- Chin-Chi Chen
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269
| | - Barbara G Mellone
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269 Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
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Abstract
Genomic variation is a source of functional diversity that is typically studied in genic and non-coding regulatory regions. However, the extent of variation within noncoding portions of the human genome, particularly highly repetitive regions, and the functional consequences are not well understood. Satellite DNA, including α satellite DNA found at human centromeres, comprises up to 10% of the genome, but is difficult to study because its repetitive nature hinders contiguous sequence assemblies. We recently described variation within α satellite DNA that affects centromere function. On human chromosome 17 (HSA17), we showed that size and sequence polymorphisms within primary array D17Z1 are associated with chromosome aneuploidy and defective centromere architecture. However, HSA17 can counteract this instability by assembling the centromere at a second, "backup" array lacking variation. Here, we discuss our findings in a broader context of human centromere assembly, and highlight areas of future study to uncover links between genomic and epigenetic features of human centromeres.
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Affiliation(s)
- Lori L Sullivan
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
| | - Kimberline Chew
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
| | - Beth A Sullivan
- a Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
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Wolff F, Leisch M, Greil R, Risch A, Pleyer L. The double-edged sword of (re)expression of genes by hypomethylating agents: from viral mimicry to exploitation as priming agents for targeted immune checkpoint modulation. Cell Commun Signal 2017; 15:13. [PMID: 28359286 PMCID: PMC5374693 DOI: 10.1186/s12964-017-0168-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/21/2017] [Indexed: 12/20/2022] Open
Abstract
Hypomethylating agents (HMAs) have been widely used over the last decade, approved for use in myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML) and acute myeloid leukemia (AML). The proposed central mechanism of action of HMAs, is the reversal of aberrant methylation in tumor cells, thus reactivating CpG-island promoters and leading to (re)expression of tumor suppressor genes. Recent investigations into the mode of action of azacitidine (AZA) and decitabine (DAC) have revealed new molecular mechanisms that impinge on tumor immunity via induction of an interferon response, through activation of endogenous retroviral elements (ERVs) that are normally epigenetically silenced. Although the global demethylation of DNA by HMAs can induce anti-tumor effects, it can also upregulate the expression of inhibitory immune checkpoint receptors and their ligands, resulting in secondary resistance to HMAs. Recent studies have, however, suggested that this could be exploited to prime or (re)sensitize tumors to immune checkpoint inhibitor therapies. In recent years, immune checkpoints have been targeted by novel therapies, with the aim of (re)activating the host immune system to specifically eliminate malignant cells. Antibodies blocking checkpoint receptors have been FDA-approved for some solid tumors and a plethora of clinical trials testing these and other checkpoint inhibitors are under way. This review will discuss AZA and DAC novel mechanisms of action resulting from the re-expression of pathologically hypermethylated promoters of gene sets that are related to interferon signaling, antigen presentation and inflammation. We also review new insights into the molecular mechanisms of action of transient, low-dose HMAs on various tumor types and discuss the potential of new treatment options and combinations.
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Affiliation(s)
- Florian Wolff
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Michael Leisch
- 3rd Medical Department with Hematology and Medical Oncology, Hemostaseology, Rheumatology and Infectious Diseases, Laboratory for Immunological and Molecular Cancer Research, Oncologic Center, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, A-5020, Salzburg, Austria
| | - Richard Greil
- 3rd Medical Department with Hematology and Medical Oncology, Hemostaseology, Rheumatology and Infectious Diseases, Laboratory for Immunological and Molecular Cancer Research, Oncologic Center, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, A-5020, Salzburg, Austria.,Salzburg Cancer Research Institute - Center for Clinical Cancer and Immunology Trials, Salzburg, Austria.,Cancer Cluster Salzburg, Salzburg, Austria
| | - Angela Risch
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria.,Cancer Cluster Salzburg, Salzburg, Austria
| | - Lisa Pleyer
- 3rd Medical Department with Hematology and Medical Oncology, Hemostaseology, Rheumatology and Infectious Diseases, Laboratory for Immunological and Molecular Cancer Research, Oncologic Center, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, A-5020, Salzburg, Austria. .,Salzburg Cancer Research Institute - Center for Clinical Cancer and Immunology Trials, Salzburg, Austria. .,Cancer Cluster Salzburg, Salzburg, Austria.
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47
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Papasotiriou I, Pantopikou K, Apostolou P. L1 retrotransposon expression in circulating tumor cells. PLoS One 2017; 12:e0171466. [PMID: 28166262 PMCID: PMC5293242 DOI: 10.1371/journal.pone.0171466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/21/2017] [Indexed: 11/18/2022] Open
Abstract
Long interspersed nuclear element 1 (LINE-1 or L1) belongs to the non-long terminal repeat (non-LTR) retrotransposon family, which has been implicated in carcinogenesis and disease progression. Circulating tumor cells (CTCs) are also known to be involved in cancer progression. The present study aimed to compare the L1 expression between circulating tumor cells and non-cancerous samples. Blood samples were collected from 10 healthy individuals and 22 patients with different types of cancer. The whole blood cells were isolated using enrichment protocols and the DNA and RNA were extracted. RT-qPCR was performed for L1-ORF1 (open reading frame 1) and L1-ORF2, using 18S rRNA as the reference gene. The data were analyzed with the Livak method and statistical analyses were carried out with the Mann-Whitney and Kruskal-Wallis tests. In parallel with the above molecular biology experiments, FISH experiments were performed on the interphase nuclei of the cells for the detection of ORF2 RNA. DNA analysis revealed the presence of both ORF1 and ORF2 in all samples. RNA expression experiments demonstrated that ORF1 was not expressed in all samples, while ORF2 was expressed at varying levels in the non-cancer samples and the samples representing the different cancer types. A significant difference in ORF2 expression was observed between the CTCs and non-cancer samples (p = 0,00043), and significant differences were also observed between normal and lung (p = 0,034), pancreatic (p = 0,022), prostate (p = 0,014), and unknown primary of origin (p = 0,0039) cancer samples. Cytogenetic analysis revealed higher levels of ORF2 in the nuclei of CTCs than in normal samples. This study highlights the significant difference in L1-ORF2 expression between CTCs and normal samples. The increased expression levels observed for CTCs may be correlated with the characteristic features of these cells.
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48
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Manzardo AM, Butler MG. Examination of Global Methylation and Targeted Imprinted Genes in Prader-Willi Syndrome. ACTA ACUST UNITED AC 2017; 2. [PMID: 28111641 DOI: 10.21767/2472-1158.100026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CONTEXT Methylation changes observed in Prader-Willi syndrome (PWS) may impact global methylation as well as regional methylation status of imprinted genes on chromosome 15 (in cis) or other imprinted obesity-related genes on other chromosomes (in trans) leading to differential effects on gene expression impacting obesity phenotype unique to (PWS). OBJECTIVE Characterize the global methylation profiles and methylation status for select imprinted genes associated with obesity phenotype in a well-characterized imprinted, obesity-related syndrome (PWS) relative to a cohort of obese and non-obese individuals. DESIGN Global methylation was assayed using two methodologies: 1) enriched LINE-1 repeat sequences by EpigenDx and 2) ELISA-based immunoassay method sensitive to genomic 5-methylcytosine by Epigentek. Target gene methylation patterns at selected candidate obesity gene loci were determined using methylation-specific PCR. SETTING Study participants were recruited as part of an ongoing research program on obesity-related genomics and Prader-Willi syndrome. PARTICIPANTS Individuals with non-syndromic obesity (N=26), leanness (N=26) and PWS (N=39). RESULTS A detailed characterization of the imprinting status of select target genes within the critical PWS 15q11-q13 genomic region showed enhanced cis but not trans methylation of imprinted genes. No significant differences in global methylation were found between non-syndromic obese, PWS or non-obese controls. INTERVENTION None. MAIN OUTCOME MEASURES Percentage methylation and the methylation index. CONCLUSION The methylation abnormality in PWS due to errors of genomic imprinting effects both upstream and downstream effectors in the 15q11-q13 region showing enhanced cis but not trans methylation of imprinted genes. Obesity in our subject cohorts did not appear to impact global methylation levels using the described methodology.
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Affiliation(s)
- A M Manzardo
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, 3901 Rainbow Blvd, MS 4015, Kansas City, Kansas, USA
| | - M G Butler
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, 3901 Rainbow Blvd, MS 4015, Kansas City, Kansas, USA; Department of Pediatrics, University of Kansas Medical Center, Kansas City, Kansas, USA
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Miga KH. The Promises and Challenges of Genomic Studies of Human Centromeres. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:285-304. [PMID: 28840242 DOI: 10.1007/978-3-319-58592-5_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human centromeres are genomic regions that act as sites of kinetochore assembly to ensure proper chromosome segregation during mitosis and meiosis. Although the biological importance of centromeres in genome stability, and ultimately, cell viability are well understood, the complete sequence content and organization in these multi-megabase-sized regions remains unknown. The lack of a high-resolution reference assembly inhibits standard bioinformatics protocols, and as a result, sequence-based studies involving human centromeres lag far behind the advances made for the non-repetitive sequences in the human genome. In this chapter, I introduce what is known about the genomic organization in the highly repetitive regions spanning human centromeres, and discuss the challenges these sequences pose for assembly, alignment, and data interpretation. Overcoming these obstacles is expected to issue a new era for centromere genomics, which will offer new discoveries in basic cell biology and human biomedical research.
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Affiliation(s)
- Karen H Miga
- Center for Biomolecular Science and Engineering, University of California, Santa Cruz, CA, USA.
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Giulotto E, Raimondi E, Sullivan KF. The Unique DNA Sequences Underlying Equine Centromeres. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:337-354. [PMID: 28840244 DOI: 10.1007/978-3-319-58592-5_14] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Centromeres are highly distinctive genetic loci whose function is specified largely by epigenetic mechanisms. Understanding the role of DNA sequences in centromere function has been a daunting task due to the highly repetitive nature of centromeres in animal chromosomes. The discovery of a centromere devoid of satellite DNA in the domestic horse consolidated observations on the epigenetic nature of centromere identity, showing that entirely natural chromosomes could function without satellite DNA cues. Horses belong to the genus Equus which exhibits a very high degree of evolutionary plasticity in centromere position and DNA sequence composition. Examination of horses has revealed that the position of the satellite-free centromere is variable among individuals. Analysis of centromere location and composition in other Equus species, including domestic donkey and zebras, confirms that the satellite-less configuration of centromeres is common in this group which has undergone particularly rapid karyotype evolution. These features have established the equids as a new mammalian system in which to investigate the molecular organization, dynamics and evolutionary behaviour of centromeres.
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Affiliation(s)
- Elena Giulotto
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 1, 27100, Pavia, Italy.
| | - Elena Raimondi
- Dipartimento di Biologia e Biotecnologie, Università di Pavia, Via Ferrata 1, 27100, Pavia, Italy
| | - Kevin F Sullivan
- National University of Ireland Galway, University Road, Galway, Ireland
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