1
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Kyriacou E, Heun P. Centromere structure and function: lessons from Drosophila. Genetics 2023; 225:iyad170. [PMID: 37931172 PMCID: PMC10697814 DOI: 10.1093/genetics/iyad170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 09/01/2023] [Indexed: 11/08/2023] Open
Abstract
The fruit fly Drosophila melanogaster serves as a powerful model organism for advancing our understanding of biological processes, not just by studying its similarities with other organisms including ourselves but also by investigating its differences to unravel the underlying strategies that evolved to achieve a common goal. This is particularly true for centromeres, specialized genomic regions present on all eukaryotic chromosomes that function as the platform for the assembly of kinetochores. These multiprotein structures play an essential role during cell division by connecting chromosomes to spindle microtubules in mitosis and meiosis to mediate accurate chromosome segregation. Here, we will take a historical perspective on the study of fly centromeres, aiming to highlight not only the important similarities but also the differences identified that contributed to advancing centromere biology. We will discuss the current knowledge on the sequence and chromatin organization of fly centromeres together with advances for identification of centromeric proteins. Then, we will describe both the factors and processes involved in centromere organization and how they work together to provide an epigenetic identity to the centromeric locus. Lastly, we will take an evolutionary point of view of centromeres and briefly discuss current views on centromere drive.
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Affiliation(s)
- Eftychia Kyriacou
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Patrick Heun
- Wellcome Centre of Cell Biology, School of Biological Sciences, University of Edinburgh, EH9 3BF Edinburgh, UK
- Department of Biology, Technische Universität Darmstadt, 64287 Darmstadt, Germany
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2
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Xue C, Liu G, Sun S, Liu X, Guo R, Cheng Z, Yu H, Gu M, Liu K, Zhou Y, Zhang T, Gong Z. De novo centromere formation in pericentromeric region of rice chromosome 8. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:859-871. [PMID: 35678753 DOI: 10.1111/tpj.15862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Neocentromeres develop when kinetochores assemble de novo at DNA loci that are not previously associated with CenH3 nucleosomes, and can rescue rearranged chromosomes that have lost a functional centromere. The molecular mechanisms associated with neocentromere formation in plants have been elusive. Here, we developed a Xian (indica) rice line with poor growth performance in the field due to approximately 272 kb deletion that spans centromeric DNA sequences, including the centromeric satellite repeat CentO, in the centromere of chromosome 8 (Cen8). The CENH3-binding domains were expanded downstream of the original CentO position in Cen8, which revealed a de novo centromere formation in rice. The neocentromere formation avoids chromosomal regions containing functional genes. Meanwhile, canonical histone H3 was replaced by CENH3 in the regions with low CENH3 levels, and the CenH3 nucleosomes in these regions became more periodic. In addition, we identified active genes in the deleted centromeric region, which are essential for chloroplast growth and development. In summary, our results provide valuable insights into neocentromere formation and show that functional genes exist in the centromeric regions of plant chromosomes.
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Affiliation(s)
- Chao Xue
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Guanqing Liu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Shang Sun
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Xiaoyu Liu
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Rui Guo
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zhukuan Cheng
- State Key Lab of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hengxiu Yu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Minghong Gu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Kai Liu
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Yong Zhou
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Tao Zhang
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Zhiyun Gong
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology, Agricultural College of Yangzhou University, Yangzhou, 225009, China
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
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3
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Thakur J, Packiaraj J, Henikoff S. Sequence, Chromatin and Evolution of Satellite DNA. Int J Mol Sci 2021; 22:ijms22094309. [PMID: 33919233 PMCID: PMC8122249 DOI: 10.3390/ijms22094309] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/15/2022] Open
Abstract
Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protection. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embedded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.
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Affiliation(s)
- Jitendra Thakur
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
- Correspondence:
| | - Jenika Packiaraj
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Fred Hutchinson Cancer Research Center, Howard Hughes Medical Institute, Seattle, WA 98109, USA
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4
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Smith OK, Limouse C, Fryer KA, Teran NA, Sundararajan K, Heald R, Straight AF. Identification and characterization of centromeric sequences in Xenopus laevis. Genome Res 2021; 31:958-967. [PMID: 33875480 PMCID: PMC8168581 DOI: 10.1101/gr.267781.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 04/08/2021] [Indexed: 11/24/2022]
Abstract
Centromeres play an essential function in cell division by specifying the site of kinetochore formation on each chromosome for mitotic spindle attachment. Centromeres are defined epigenetically by the histone H3 variant Centromere Protein A (Cenpa). Cenpa nucleosomes maintain the centromere by designating the site for new Cenpa assembly after dilution by replication. Vertebrate centromeres assemble on tandem arrays of repetitive sequences, but the function of repeat DNA in centromere formation has been challenging to dissect due to the difficulty in manipulating centromeres in cells. Xenopus laevis egg extracts assemble centromeres in vitro, providing a system for studying centromeric DNA functions. However, centromeric sequences in Xenopus laevis have not been extensively characterized. In this study, we combine Cenpa ChIP-seq with a k-mer based analysis approach to identify the Xenopus laevis centromere repeat sequences. By in situ hybridization, we show that Xenopus laevis centromeres contain diverse repeat sequences, and we map the centromere position on each Xenopus laevis chromosome using the distribution of centromere-enriched k-mers. Our identification of Xenopus laevis centromere sequences enables previously unapproachable centromere genomic studies. Our approach should be broadly applicable for the analysis of centromere and other repetitive sequences in any organism.
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Affiliation(s)
- Owen K Smith
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA.,Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Charles Limouse
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA
| | - Kelsey A Fryer
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, California 94305-5120, USA
| | - Nicole A Teran
- Department of Genetics, Stanford University School of Medicine, Stanford, California 94305-5120, USA
| | - Kousik Sundararajan
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California 94720-3200, USA
| | - Aaron F Straight
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA
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5
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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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6
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Palladino J, Chavan A, Sposato A, Mason TD, Mellone BG. Targeted De Novo Centromere Formation in Drosophila Reveals Plasticity and Maintenance Potential of CENP-A Chromatin. Dev Cell 2020; 52:379-394.e7. [PMID: 32049040 DOI: 10.1016/j.devcel.2020.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/17/2019] [Accepted: 01/06/2020] [Indexed: 11/25/2022]
Abstract
Centromeres are essential for accurate chromosome segregation and are marked by centromere protein A (CENP-A) nucleosomes. Mis-targeted CENP-A chromatin has been shown to seed centromeres at non-centromeric DNA. However, the requirements for such de novo centromere formation and transmission in vivo remain unknown. Here, we employ Drosophila melanogaster and the LacI/lacO system to investigate the ability of targeted de novo centromeres to assemble and be inherited through development. De novo centromeres form efficiently at six distinct genomic locations, which include actively transcribed chromatin and heterochromatin, and cause widespread chromosomal instability. During tethering, de novo centromeres sometimes prevail, causing the loss of the endogenous centromere via DNA breaks and HP1-dependent epigenetic inactivation. Transient induction of de novo centromeres and chromosome healing in early embryogenesis show that, once established, these centromeres can be maintained through development. Our results underpin the ability of CENP-A chromatin to establish and sustain mitotic centromere function in Drosophila.
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Affiliation(s)
- Jason Palladino
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Ankita Chavan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Anthony Sposato
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Timothy D Mason
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Barbara G Mellone
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA.
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7
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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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8
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Jedlicka P, Lexa M, Vanat I, Hobza R, Kejnovsky E. Nested plant LTR retrotransposons target specific regions of other elements, while all LTR retrotransposons often target palindromes and nucleosome-occupied regions: in silico study. Mob DNA 2019; 10:50. [PMID: 31871489 PMCID: PMC6911290 DOI: 10.1186/s13100-019-0186-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/31/2019] [Indexed: 01/08/2023] Open
Abstract
Background Nesting is common in LTR retrotransposons, especially in large genomes containing a high number of elements. Results We analyzed 12 plant genomes and obtained 1491 pairs of nested and original (pre-existing) LTR retrotransposons. We systematically analyzed mutual nesting of individual LTR retrotransposons and found that certain families, more often belonging to the Ty3/gypsy than Ty1/copia superfamilies, showed a higher nesting frequency as well as a higher preference for older copies of the same family ("autoinsertions"). Nested LTR retrotransposons were preferentially located in the 3'UTR of other LTR retrotransposons, while coding and regulatory regions (LTRs) are not commonly targeted. Insertions displayed a weak preference for palindromes and were associated with a strong positional pattern of higher predicted nucleosome occupancy. Deviation from randomness in target site choice was also found in 13,983 non-nested plant LTR retrotransposons. Conclusions We reveal that nesting of LTR retrotransposons is not random. Integration is correlated with sequence composition, secondary structure and the chromatin environment. Insertion into retrotransposon positions with a low negative impact on family fitness supports the concept of the genome being viewed as an ecosystem of various elements.
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Affiliation(s)
- Pavel Jedlicka
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 61200 Brno, Czech Republic
| | - Matej Lexa
- 2Faculty of Informatics, Masaryk University, Botanicka 68a, 60200 Brno, Czech Republic
| | - Ivan Vanat
- 2Faculty of Informatics, Masaryk University, Botanicka 68a, 60200 Brno, Czech Republic
| | - Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 61200 Brno, Czech Republic
| | - Eduard Kejnovsky
- Department of Plant Developmental Genetics, Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 61200 Brno, Czech Republic
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9
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Mills WK, Lee YCG, Kochendoerfer AM, Dunleavy EM, Karpen GH. RNA from a simple-tandem repeat is required for sperm maturation and male fertility in Drosophila melanogaster. eLife 2019; 8:48940. [PMID: 31687931 PMCID: PMC6879302 DOI: 10.7554/elife.48940] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/03/2019] [Indexed: 11/26/2022] Open
Abstract
Tandemly-repeated DNAs, or satellites, are enriched in heterochromatic regions of eukaryotic genomes and contribute to nuclear structure and function. Some satellites are transcribed, but we lack direct evidence that specific satellite RNAs are required for normal organismal functions. Here, we show satellite RNAs derived from AAGAG tandem repeats are transcribed in many cells throughout Drosophila melanogaster development, enriched in neurons and testes, often localized within heterochromatic regions, and important for viability. Strikingly, we find AAGAG transcripts are necessary for male fertility, and that AAGAG RNA depletion results in defective histone-protamine exchange, sperm maturation and chromatin organization. Since these events happen late in spermatogenesis when the transcripts are not detected, we speculate that AAGAG RNA in primary spermatocytes ‘primes’ post-meiosis steps for sperm maturation. In addition to demonstrating essential functions for AAGAG RNAs, comparisons between closely related Drosophila species suggest that satellites and their transcription evolve quickly to generate new functions.
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Affiliation(s)
- Wilbur Kyle Mills
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Lawrence Berkeley National Laboratory, Berkeley, United States
| | - Yuh Chwen G Lee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Lawrence Berkeley National Laboratory, Berkeley, United States.,Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, United States
| | | | - Elaine M Dunleavy
- Centre for Chromosome Biology, National University of Ireland, Galway, Ireland
| | - Gary H Karpen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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10
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The Impact of Centromeres on Spatial Genome Architecture. Trends Genet 2019; 35:565-578. [PMID: 31200946 DOI: 10.1016/j.tig.2019.05.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/06/2019] [Accepted: 05/09/2019] [Indexed: 01/01/2023]
Abstract
The development of new technologies and experimental techniques is enabling researchers to see what was once unable to be seen. For example, the centromere was first seen as the mediator between spindle fiber and chromosome during mitosis and meiosis. Although this continues to be its most prominent role, we now know that the centromere functions beyond cellular division with important roles in genome organization and chromatin regulation. Here we aim to share the structures and functions of centromeres in various organisms beginning with the diversity of their DNA sequence anatomies. We zoom out to describe their position in the nucleus and ultimately detail the different ways they contribute to genome organization and regulation at the spatial level.
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11
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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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12
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Nakagawa T, Okita AK. Transcriptional silencing of centromere repeats by heterochromatin safeguards chromosome integrity. Curr Genet 2019; 65:1089-1098. [PMID: 30997531 DOI: 10.1007/s00294-019-00975-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/11/2019] [Accepted: 04/13/2019] [Indexed: 12/25/2022]
Abstract
The centromere region of chromosomes consists of repetitive DNA sequences, and is, therefore, one of the fragile sites of chromosomes in many eukaryotes. In the core region, the histone H3 variant CENP-A forms centromere-specific nucleosomes that are required for kinetochore formation. In the pericentromeric region, histone H3 is methylated at lysine 9 (H3K9) and heterochromatin is formed. The transcription of pericentromeric repeats by RNA polymerase II is strictly repressed by heterochromatin. However, the role of the transcriptional silencing of the pericentromeric repeats remains largely unclear. Here, we focus on the chromosomal rearrangements that occur at the repetitive centromeres, and highlight our recent studies showing that transcriptional silencing by heterochromatin suppresses gross chromosomal rearrangements (GCRs) at centromeres in fission yeast. Inactivation of the Clr4 methyltransferase, which is essential for the H3K9 methylation, increased GCRs with breakpoints located in centromeric repeats. However, mutations in RNA polymerase II or the transcription factor Tfs1/TFIIS, which promotes restart of RNA polymerase II following its backtracking, reduced the GCRs that occur in the absence of Clr4, demonstrating that heterochromatin suppresses GCRs by repressing the Tfs1-dependent transcription. We also discuss how the transcriptional restart gives rise to chromosomal rearrangements at centromeres.
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Affiliation(s)
- Takuro Nakagawa
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.
| | - Akiko K Okita
- Department of Biological Sciences, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
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13
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Jagannathan M, Cummings R, Yamashita YM. The modular mechanism of chromocenter formation in Drosophila. eLife 2019; 8:43938. [PMID: 30741633 PMCID: PMC6382350 DOI: 10.7554/elife.43938] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/08/2019] [Indexed: 02/07/2023] Open
Abstract
A central principle underlying the ubiquity and abundance of pericentromeric satellite DNA repeats in eukaryotes has remained poorly understood. Previously we proposed that the interchromosomal clustering of satellite DNAs into nuclear structures known as chromocenters ensures encapsulation of all chromosomes into a single nucleus (Jagannathan et al., 2018). Chromocenter disruption led to micronuclei formation, resulting in cell death. Here we show that chromocenter formation is mediated by a ‘modular’ network, where associations between two sequence-specific satellite DNA-binding proteins, D1 and Prod, bound to their cognate satellite DNAs, bring the full complement of chromosomes into the chromocenter. D1 prod double mutants die during embryogenesis, exhibiting enhanced phenotypes associated with chromocenter disruption, revealing the universal importance of satellite DNAs and chromocenters. Taken together, we propose that associations between chromocenter modules, consisting of satellite DNA binding proteins and their cognate satellite DNA, package the Drosophila genome within a single nucleus.
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Affiliation(s)
- Madhav Jagannathan
- Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Ryan Cummings
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, United States
| | - Yukiko M Yamashita
- Howard Hughes Medical Institute, University of Michigan, Ann Arbor, United States.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States
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14
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Bobkov GOM, Gilbert N, Heun P. Centromere transcription allows CENP-A to transit from chromatin association to stable incorporation. J Cell Biol 2018; 217:1957-1972. [PMID: 29626011 PMCID: PMC5987708 DOI: 10.1083/jcb.201611087] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 07/11/2017] [Accepted: 03/14/2018] [Indexed: 12/11/2022] Open
Abstract
How transcription contributes to the loading of the centromere histone CENP-A is unclear. Bobkov et al. report that transcription-mediated chromatin remodeling enables the transition of centromeric CENP-A from chromatin association to full nucleosome incorporation. Centromeres are essential for chromosome segregation and are specified epigenetically by the presence of the histone H3 variant CENP-A. In flies and humans, replenishment of the centromeric mark is uncoupled from DNA replication and requires the removal of H3 “placeholder” nucleosomes. Although transcription at centromeres has been previously linked to the loading of new CENP-A, the underlying molecular mechanism remains poorly understood. Here, we used Drosophila melanogaster tissue culture cells to show that centromeric presence of actively transcribing RNA polymerase II temporally coincides with de novo deposition of dCENP-A. Using a newly developed dCENP-A loading system that is independent of acute transcription, we found that short inhibition of transcription impaired dCENP-A incorporation into chromatin. Interestingly, initial targeting of dCENP-A to centromeres was unaffected, revealing two stability states of newly loaded dCENP-A: a salt-sensitive association with the centromere and a salt-resistant chromatin-incorporated form. This suggests that transcription-mediated chromatin remodeling is required for the transition of dCENP-A to fully incorporated nucleosomes at the centromere.
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Affiliation(s)
- Georg O M Bobkov
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, Scotland, UK.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Nick Gilbert
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Patrick Heun
- Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, Scotland, UK
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15
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Jagannathan M, Yamashita YM. Function of Junk: Pericentromeric Satellite DNA in Chromosome Maintenance. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2018; 82:319-327. [PMID: 29610245 DOI: 10.1101/sqb.2017.82.034504] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Satellite DNAs are simple tandem repeats that exist at centromeric and pericentromeric regions on eukaryotic chromosomes. Unlike the centromeric satellite DNA that comprises the vast majority of natural centromeres, function(s) for the much more abundant pericentromeric satellite repeats are poorly understood. In fact, the lack of coding potential allied with rapid divergence of repeat sequences across eukaryotes has led to their dismissal as "junk DNA" or "selfish parasites." Although implicated in various biological processes, a conserved function for pericentromeric satellite DNA remains unidentified. We have addressed the role of satellite DNA through studying chromocenters, a cytological aggregation of pericentromeric satellite DNA from multiple chromosomes into DNA-dense nuclear foci. We have shown that multivalent satellite DNA-binding proteins cross-link pericentromeric satellite DNA on chromosomes into chromocenters. Disruption of chromocenters results in the formation of micronuclei, which arise by budding off the nucleus during interphase. We propose a model that satellite DNAs are critical chromosome elements that are recognized by satellite DNA-binding proteins and incorporated into chromocenters. We suggest that chromocenters function to preserve the entire chromosomal complement in a single nucleus, a fundamental and unquestioned feature of eukaryotic genomes. We speculate that the rapid divergence of satellite DNA sequences between closely related species results in discordant chromocenter function and may underlie speciation and hybrid incompatibility.
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Affiliation(s)
- Madhav Jagannathan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - Yukiko M Yamashita
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109.,Howard Hughes Medical Institute, University of Michigan, Ann Arbor, Michigan 48109
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16
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Jagannathan M, Cummings R, Yamashita YM. A conserved function for pericentromeric satellite DNA. eLife 2018; 7:34122. [PMID: 29578410 PMCID: PMC5957525 DOI: 10.7554/elife.34122] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/24/2018] [Indexed: 12/27/2022] Open
Abstract
A universal and unquestioned characteristic of eukaryotic cells is that the genome is divided into multiple chromosomes and encapsulated in a single nucleus. However, the underlying mechanism to ensure such a configuration is unknown. Here, we provide evidence that pericentromeric satellite DNA, which is often regarded as junk, is a critical constituent of the chromosome, allowing the packaging of all chromosomes into a single nucleus. We show that the multi-AT-hook satellite DNA-binding proteins, Drosophila melanogaster D1 and mouse HMGA1, play an evolutionarily conserved role in bundling pericentromeric satellite DNA from heterologous chromosomes into ‘chromocenters’, a cytological association of pericentromeric heterochromatin. Defective chromocenter formation leads to micronuclei formation due to budding from the interphase nucleus, DNA damage and cell death. We propose that chromocenter and satellite DNA serve a fundamental role in encapsulating the full complement of the genome within a single nucleus, the universal characteristic of eukaryotic cells. On Earth, life is divided into three domains. The smallest of these domains includes all the creatures, from sunflowers to yeasts to humans, that have the genetic information within their cells encased in a structure known as the nucleus. The genomes of these organisms are formed of long pieces of DNA, called chromosomes, which are packaged tightly and then unpackaged every time the cell divides. When a cell is not dividing, the chromosomes in the nucleus are loosely bundled up together. It is well known that DNA is the blueprint for the building blocks of life, but actually most of the genetic information in a cell codes for nothing, and has unknown roles. An example of such ‘junk DNA’ is pericentrometric satellite DNA, small repetitive sequences found on all chromosomes. However, new experiments by Jagannathan et al. show that, in the nucleus of animal cells, certain DNA binding proteins make chromosomes huddle together by attaching to multiple pericentrometric satellite DNA sequences on different chromosomes. In fact, if these proteins are removed from mice and fruit flies cells grown in the laboratory, the chromosomes cannot be clustered together. Instead, they ‘float away’, and the membranes of the nucleus get damaged, possibly buckling under the pressure of the unorganized DNA. These events damage the genetic information, which can lead to the cell dying or forming tumors. ‘Junk DNA’ therefore appears to participate in fundamental cellular processes across species, a result that opens up several new lines of research.
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Affiliation(s)
- Madhav Jagannathan
- Life Sciences Institute, University of Michigan, Ann Arbor, United States
| | - Ryan Cummings
- Life Sciences Institute, University of Michigan, Ann Arbor, United States.,Howard Hughes Medical Institute, University of Michigan, Ann Arbor, United States
| | - Yukiko M Yamashita
- Life Sciences Institute, University of Michigan, Ann Arbor, United States.,Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States.,Howard Hughes Medical Institute, University of Michigan, Ann Arbor, United States
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17
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Simple and Complex Centromeric Satellites in Drosophila Sibling Species. Genetics 2018; 208:977-990. [PMID: 29305387 PMCID: PMC5844345 DOI: 10.1534/genetics.117.300620] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 01/03/2018] [Indexed: 12/19/2022] Open
Abstract
Centromeres are the chromosomal sites of assembly for kinetochores, the protein complexes that attach to spindle fibers and mediate separation of chromosomes to daughter cells in mitosis and meiosis. In most multicellular organisms, centromeres comprise a single specific family of tandem repeats-often 100-400 bp in length-found on every chromosome, typically in one location within heterochromatin. Drosophila melanogaster is unusual in that the heterochromatin contains many families of mostly short (5-12 bp) tandem repeats, none of which appear to be present at all centromeres, and none of which are found only at centromeres. Although centromere sequences from a minichromosome have been identified and candidate centromere sequences have been proposed, the DNA sequences at native Drosophila centromeres remain unknown. Here we use native chromatin immunoprecipitation to identify the centromeric sequences bound by the foundational kinetochore protein cenH3, known in vertebrates as CENP-A. In D. melanogaster, these sequences include a few families of 5- and 10-bp repeats; but in closely related D. simulans, the centromeres comprise more complex repeats. The results suggest that a recent expansion of short repeats has replaced more complex centromeric repeats in D. melanogaster.
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18
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Abstract
The genetic material, contained on chromosomes, is often described as the "blueprint for life." During nuclear division, the chromosomes are pulled into each of the two daughter nuclei by the coordination of spindle microtubules, kinetochores, centromeres, and chromatin. These four functional units must link the chromosomes to the microtubules, signal to the cell when the attachment is made so that division can proceed, and withstand the force generated by pulling the chromosomes to either daughter cell. To perform each of these functions, kinetochores are large protein complexes, approximately 5MDa in size, and they contain at least 45 unique proteins. Many of the central components in the kinetochore are well conserved, yielding a common core of proteins forming consistent structures. However, many of the peripheral subcomplexes vary between different taxonomic groups, including changes in primary sequence and gain or loss of whole proteins. It is still unclear how significant these changes are, and answers to this question may provide insights into adaptation to specific lifestyles or progression of disease that involve chromosome instability.
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19
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de Lima LG, Svartman M, Kuhn GCS. Dissecting the Satellite DNA Landscape in Three Cactophilic Drosophila Sequenced Genomes. G3 (BETHESDA, MD.) 2017; 7:2831-2843. [PMID: 28659292 PMCID: PMC5555486 DOI: 10.1534/g3.117.042093] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/26/2017] [Indexed: 01/12/2023]
Abstract
Eukaryote genomes are replete with repetitive DNAs. This class includes tandemly repeated satellite DNAs (satDNA) which are among the most abundant, fast evolving (yet poorly studied) genomic components. Here, we used high-throughput sequencing data from three cactophilic Drosophila species, D. buzzatii, D. seriema, and D. mojavensis, to access and study their whole satDNA landscape. In total, the RepeatExplorer software identified five satDNAs, three previously described (pBuM, DBC-150 and CDSTR198) and two novel ones (CDSTR138 and CDSTR130). Only pBuM is shared among all three species. The satDNA repeat length falls within only two classes, between 130 and 200 bp or between 340 and 390 bp. FISH on metaphase and polytene chromosomes revealed the presence of satDNA arrays in at least one of the following genomic compartments: centromeric, telomeric, subtelomeric, or dispersed along euchromatin. The chromosomal distribution ranges from a single chromosome to almost all chromosomes of the complement. Fiber-FISH and sequence analysis of contigs revealed interspersion between pBuM and CDSTR130 in the microchromosomes of D. mojavensis Phylogenetic analyses showed that the pBuM satDNA underwent concerted evolution at both interspecific and intraspecific levels. Based on RNA-seq data, we found transcription activity for pBuM (in D. mojavensis) and CDSTR198 (in D. buzzatii) in all five analyzed developmental stages, most notably in pupae and adult males. Our data revealed that cactophilic Drosophila present the lowest amount of satDNAs (1.9-2.9%) within the Drosophila genus reported so far. We discuss how our findings on the satDNA location, abundance, organization, and transcription activity may be related to functional aspects.
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Affiliation(s)
- Leonardo G de Lima
- Laboratório de Citogenômica Evolutiva, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Marta Svartman
- Laboratório de Citogenômica Evolutiva, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Gustavo C S Kuhn
- Laboratório de Citogenômica Evolutiva, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901, Brazil
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20
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Zhang R, Xue C, Liu G, Liu X, Zhang M, Wang X, Zhang T, Gong Z. Segmental Duplication of Chromosome 11 and its Implications for Cell Division and Genome-wide Expression in Rice. Sci Rep 2017; 7:2689. [PMID: 28577021 PMCID: PMC5457480 DOI: 10.1038/s41598-017-02796-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/19/2017] [Indexed: 11/18/2022] Open
Abstract
Segmental duplication is a major structural variation that occurs in chromosomes. Duplication leads to the production of gene copies with increased numbers of related repeat segments, causing the global genome to be in a state of imbalance. In addition, if the added segment contains a centromeric specific DNA, the duplicated chromosome will have structural multiple centromeres. We identified a segmental duplication containing structurally tricentric regions derived from the short arm of chromosome 11 (11L∙ + 11L∙ + 11S∙11S∙11S∙11S, “∙” represents the centromeric DNA repeat loci), and analyzed its implications for cell division and genome-wide expression. In the variant, only the middle centromere of 11S∙11S∙11S∙11S is functionally active. As a result, the structurally tricentric chromosome was stable in mitosis, because it is actually a functional monocentric chromosome. However, the structurally tricentric chromosome, which usually formed a bivalent, was either arranged on the equatorial plane or was lagging, which affected its separation during meiosis. Furthermore, RNA-seq and RT-qPCR analysis showed that the segmental duplication affected genome-wide expression patterns. 34.60% of genes in repeat region showed positive dosage effect. Thus, the genes on chromosome arm 11S-2 didn’t exhibit obviously dosage compensation, as illustrated by no peak around a ratio of 1.00. However, the gene dosage effect will reduce after sexual reproduction of a generation.
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Affiliation(s)
- Rong Zhang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Chao Xue
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Guanqing Liu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Xiaoyu Liu
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Mingliang Zhang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Xiao Wang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China
| | - Tao Zhang
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
| | - Zhiyun Gong
- Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
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21
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Gerland TA, Sun B, Smialowski P, Lukacs A, Thomae AW, Imhof A. The Drosophila speciation factor HMR localizes to genomic insulator sites. PLoS One 2017; 12:e0171798. [PMID: 28207793 PMCID: PMC5312933 DOI: 10.1371/journal.pone.0171798] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 01/26/2017] [Indexed: 12/22/2022] Open
Abstract
Hybrid incompatibility between Drosophila melanogaster and D. simulans is caused by a lethal interaction of the proteins encoded by the Hmr and Lhr genes. In D. melanogaster the loss of HMR results in mitotic defects, an increase in transcription of transposable elements and a deregulation of heterochromatic genes. To better understand the molecular mechanisms that mediate HMR’s function, we measured genome-wide localization of HMR in D. melanogaster tissue culture cells by chromatin immunoprecipitation. Interestingly, we find HMR localizing to genomic insulator sites that can be classified into two groups. One group belongs to gypsy insulators and another one borders HP1a bound regions at active genes. The transcription of the latter group genes is strongly affected in larvae and ovaries of Hmr mutant flies. Our data suggest a novel link between HMR and insulator proteins, a finding that implicates a potential role for genome organization in the formation of species.
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Affiliation(s)
- Thomas Andreas Gerland
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bo Sun
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Pawel Smialowski
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Core Facility Computational Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Andrea Lukacs
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Andreas Walter Thomae
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Histone Modifications Group, Department of Molecular Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität München, Munich, Germany
- * E-mail:
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22
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Centromeres Drive a Hard Bargain. Trends Genet 2017; 33:101-117. [PMID: 28069312 DOI: 10.1016/j.tig.2016.12.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/01/2016] [Accepted: 12/05/2016] [Indexed: 12/13/2022]
Abstract
Centromeres are essential chromosomal structures that mediate the accurate distribution of genetic material during meiotic and mitotic cell divisions. In most organisms, centromeres are epigenetically specified and propagated by nucleosomes containing the centromere-specific H3 variant, centromere protein A (CENP-A). Although centromeres perform a critical and conserved function, CENP-A and the underlying centromeric DNA are rapidly evolving. This paradox has been explained by the centromere drive hypothesis, which proposes that CENP-A is undergoing an evolutionary tug-of-war with selfish centromeric DNA. Here, we review our current understanding of CENP-A evolution in relation to centromere drive and discuss classical and recent advances, including new evidence implicating CENP-A chaperones in this conflict.
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23
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Long Noncoding RNA: Genome Organization and Mechanism of Action. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1008:47-74. [PMID: 28815536 DOI: 10.1007/978-981-10-5203-3_2] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
For the last four decades, we have known that noncoding RNAs maintain critical housekeeping functions such as transcription, RNA processing, and translation. However, in the late 1990s and early 2000s, the advent of high-throughput sequencing technologies and computational tools to analyze these large sequencing datasets facilitated the discovery of thousands of small and long noncoding RNAs (lncRNAs) and their functional role in diverse biological functions. For example, lncRNAs have been shown to regulate dosage compensation, genomic imprinting, pluripotency, cell differentiation and development, immune response, etc. Here we review how lncRNAs bring about such copious functions by employing diverse mechanisms such as translational inhibition, mRNA degradation, RNA decoys, facilitating recruitment of chromatin modifiers, regulation of protein activity, regulating the availability of miRNAs by sponging mechanism, etc. In addition, we provide a detailed account of different mechanisms as well as general principles by which lncRNAs organize functionally different nuclear sub-compartments and their impact on nuclear architecture.
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24
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Meštrović N, Mravinac B, Pavlek M, Vojvoda-Zeljko T, Šatović E, Plohl M. Structural and functional liaisons between transposable elements and satellite DNAs. Chromosome Res 2016; 23:583-96. [PMID: 26293606 DOI: 10.1007/s10577-015-9483-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transposable elements (TEs) and satellite DNAs (satDNAs) are typically identified as major repetitive DNA components in eukaryotic genomes. TEs are DNA segments able to move throughout a genome while satDNAs are tandemly repeated sequences organized in long arrays. Both classes of repetitive sequences are extremely diverse, and many TEs and satDNAs exist within a genome. Although they differ in structure, genomic organization, mechanisms of spread, and evolutionary dynamics, TEs and satDNAs can share sequence similarity and organizational patterns, thus indicating that complex mutual relationships can determine their evolution, and ultimately define roles they might have on genome architecture and function. Motivated by accumulating data about sequence elements that incorporate features of both TEs and satDNAs, here we present an overview of their structural and functional liaisons.
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Affiliation(s)
| | | | - Martina Pavlek
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia
| | | | - Eva Šatović
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Miroslav Plohl
- Ruđer Bošković Institute, Bijenička 54, HR-10000, Zagreb, Croatia.
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25
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Sullivan LL, Maloney KA, Towers AJ, Gregory SG, Sullivan BA. Human centromere repositioning within euchromatin after partial chromosome deletion. Chromosome Res 2016; 24:451-466. [PMID: 27581771 DOI: 10.1007/s10577-016-9536-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
Centromeres are defined by a specialized chromatin organization that includes nucleosomes that contain the centromeric histone variant centromere protein A (CENP-A) instead of canonical histone H3. Studies in various organisms have shown that centromeric chromatin (i.e., CENP-A chromatin or centrochromatin) exhibits plasticity, in that it can assemble on different types of DNA sequences. However, once established on a chromosome, the centromere is maintained at the same position. In humans, this location is the highly homogeneous repetitive DNA alpha satellite. Mislocalization of centromeric chromatin to atypical locations can lead to genome instability, indicating that restriction of centromeres to a distinct genomic position is important for cell and organism viability. Here, we describe a rearrangement of Homo sapiens chromosome 17 (HSA17) that has placed alpha satellite DNA next to euchromatin. We show that on this mutant chromosome, CENP-A chromatin has spread from the alpha satellite into the short arm of HSA17, establishing a ∼700 kb hybrid centromeric domain that spans both repetitive and unique sequences and changes the expression of at least one gene over which it spreads. Our results illustrate the plasticity of human centromeric chromatin and suggest that heterochromatin normally constrains CENP-A chromatin onto alpha satellite DNA. This work highlights that chromosome rearrangements, particularly those that remove the pericentromere, create opportunities for centromeric nucleosomes to move into non-traditional genomic locations, potentially changing the surrounding chromatin environment and altering gene expression.
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Affiliation(s)
- Lori L Sullivan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, DUMC 3054, Durham, NC, 27710, USA
| | - Kristin A Maloney
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, DUMC 3054, Durham, NC, 27710, USA.,Department of Medicine, Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Aaron J Towers
- University Program in Genetics and Genomics, Duke University School of Medicine, Durham, NC, 27710, USA.,Quintiles, 4820 Emperor Blvd., Durham, NC, 27703, USA
| | - Simon G Gregory
- Department of Medicine, Duke Molecular Physiology Institute, 300 N. Duke Street, Durham, NC, 27701, USA.,Division of Human Genetics, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Beth A Sullivan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, DUMC 3054, Durham, NC, 27710, USA. .,Quintiles, 4820 Emperor Blvd., Durham, NC, 27703, USA.
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26
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Kinetochore assembly and function through the cell cycle. Chromosoma 2016; 125:645-59. [DOI: 10.1007/s00412-016-0608-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 01/03/2023]
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Craddock EM, Gall JG, Jonas M. Hawaiian Drosophila genomes: size variation and evolutionary expansions. Genetica 2016; 144:107-24. [PMID: 26790663 DOI: 10.1007/s10709-016-9882-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 01/09/2016] [Indexed: 01/24/2023]
Abstract
This paper reports genome sizes of one Hawaiian Scaptomyza and 16 endemic Hawaiian Drosophila species that include five members of the antopocerus species group, one member of the modified mouthpart group, and ten members of the picture wing clade. Genome size expansions have occurred independently multiple times among Hawaiian Drosophila lineages, and have resulted in an over 2.3-fold range of genome sizes among species, with the largest observed in Drosophila cyrtoloma (1C = 0.41 pg). We find evidence that these repeated genome size expansions were likely driven by the addition of significant amounts of heterochromatin and satellite DNA. For example, our data reveal that the addition of seven heterochromatic chromosome arms to the ancestral haploid karyotype, and a remarkable proportion of ~70 % satellite DNA, account for the greatly expanded size of the D. cyrtoloma genome. Moreover, the genomes of 13/17 Hawaiian picture wing species are composed of substantial proportions (22-70 %) of detectable satellites (all but one of which are AT-rich). Our results suggest that in this tightly knit group of recently evolved species, genomes have expanded, in large part, via evolutionary amplifications of satellite DNA sequences in centric and pericentric domains (especially of the X and dot chromosomes), which have resulted in longer acrocentric chromosomes or metacentrics with an added heterochromatic chromosome arm. We discuss possible evolutionary mechanisms that may have shaped these patterns, including rapid fixation of novel expanded genomes during founder-effect speciation.
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Affiliation(s)
- Elysse M Craddock
- Natural Sciences Building, Purchase College, State University of New York, 735 Anderson Hill Road, Purchase, NY, 10577, USA.
| | - Joseph G Gall
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD, USA
| | - Mark Jonas
- Natural Sciences Building, Purchase College, State University of New York, 735 Anderson Hill Road, Purchase, NY, 10577, USA
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Guo Y, Singh PK, Levin HL. A long terminal repeat retrotransposon of Schizosaccharomyces japonicus integrates upstream of RNA pol III transcribed genes. Mob DNA 2015; 6:19. [PMID: 26457121 PMCID: PMC4600332 DOI: 10.1186/s13100-015-0048-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/22/2015] [Indexed: 01/29/2023] Open
Abstract
Background Transposable elements (TEs) are common constituents of centromeres. However, it is not known what causes this relationship. Schizosaccharomyces japonicus contains 10 families of Long Terminal Repeat (LTR)-retrotransposons and these elements cluster in centromeres and telomeres. In the related yeast, Schizosaccharomyces pombe LTR-retrotransposons Tf1 and Tf2 are distributed in the promoter regions of RNA pol II transcribed genes. Sequence analysis of TEs indicates that Tj1 of S. japonicus is related to Tf1 and Tf2, and uses the same mechanism of self-primed reverse transcription. Thus, we wondered why these related retrotransposons localized in different regions of the genome. Results To characterize the integration behavior of Tj1 we expressed it in S. pombe. We found Tj1 was active and capable of generating de novo integration in the chromosomes of S. pombe. The expression of Tj1 is similar to Type C retroviruses in that a stop codon at the end of Gag must be present for efficient integration. 17 inserts were sequenced, 13 occurred within 12 bp upstream of tRNA genes and 3 occurred at other RNA pol III transcribed genes. The link between Tj1 integration and RNA pol III transcription is reminiscent of Ty3, an LTR-retrotransposon of Saccharomyces cerevisiae that interacts with TFIIIB and integrates upstream of tRNA genes. Conclusion The integration of Tj1 upstream of tRNA genes and the centromeric clustering of tRNA genes in S. japonicus demonstrate that the clustering of this TE in centromere sequences is due to a unique pattern of integration.
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Affiliation(s)
- Yabin Guo
- Present address: University of Texas Southwestern Medical Center, Dallas, Texas USA
| | - Parmit Kumar Singh
- Section on Eukaryotic Transposable Elements, Program in Cellular Regulation and Metabolism, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 18 T, room 106, Bethesda, MD 20892 USA
| | - Henry L Levin
- Section on Eukaryotic Transposable Elements, Program in Cellular Regulation and Metabolism, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Building 18 T, room 106, Bethesda, MD 20892 USA
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Abstract
Production of gametes of halved ploidy for sexual reproduction requires a specialized cell division called meiosis. The fusion of two gametes restores the original ploidy in the new generation, and meiosis thus stabilizes ploidy across generations. To ensure balanced distribution of chromosomes, pairs of homologous chromosomes (homologs) must recognize each other and pair in the first meiotic division. Recombination plays a key role in this in most studied species, but it is not the only actor and particular chromosomal regions are known to facilitate the meiotic pairing of homologs. In this review, we focus on the roles of centromeres and in particular on the clustering and pairwise associations of nonhomologous centromeres that precede stable pairing between homologs. Although details vary from species to species, it is becoming increasingly clear that these associations play active roles in the meiotic chromosome pairing process, analogous to those of the telomere bouquet.
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Affiliation(s)
- Olivier Da Ines
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France; ,
| | - Charles I White
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France; ,
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Kurdzo EL, Dawson DS. Centromere pairing--tethering partner chromosomes in meiosis I. FEBS J 2015; 282:2458-70. [PMID: 25817724 PMCID: PMC4490064 DOI: 10.1111/febs.13280] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/10/2015] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
In meiosis, homologous chromosomes face the obstacle of finding, holding onto and segregating away from their partner chromosome. There is increasing evidence, in a diverse range of organisms, that centromere–centromere interactions that occur in late prophase are an important mechanism in ensuring segregation fidelity. Centromere pairing appears to initiate when homologous chromosomes synapse in meiotic prophase. Structural proteins of the synaptonemal complex have been shown to help mediate centromere pairing, but how the structure that maintains centromere pairing differs from the structure of the synaptonemal complex along the chromosomal arms remains unknown. When the synaptonemal complex proteins disassemble from the chromosome arms in late prophase, some of these synaptonemal complex components persist at the centromeres. In yeast and Drosophila these centromere-pairing behaviors promote the proper segregation of chromosome partners that have failed to become linked by chiasmata. Recent studies of mouse spermatocytes have described centromere pairing behaviors that are similar in several respects to what has been described in the fly and yeast systems. In humans, chromosomes that fail to experience crossovers in meiosis are error-prone and are a major source of aneuploidy. The finding that centromere pairing is a conserved phenomenon raises the possibility that it may play a role in promoting the segregation fidelity of non-exchange chromosome pairs in humans.
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Affiliation(s)
- Emily L Kurdzo
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma, Health Science Center, OK, USA
| | - Dean S Dawson
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma, Health Science Center, OK, USA
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31
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Chromatin-Driven Behavior of Topologically Associating Domains. J Mol Biol 2015; 427:608-25. [DOI: 10.1016/j.jmb.2014.09.013] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/17/2014] [Accepted: 09/23/2014] [Indexed: 12/19/2022]
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Maumus F, Fiston-Lavier AS, Quesneville H. Impact of transposable elements on insect genomes and biology. CURRENT OPINION IN INSECT SCIENCE 2015; 7:30-36. [PMID: 32846669 DOI: 10.1016/j.cois.2015.01.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 12/30/2014] [Accepted: 01/06/2015] [Indexed: 06/11/2023]
Affiliation(s)
- Florian Maumus
- Unité de recherche en Génomique-Info (URGI), UR1164, INRA, RD10 route de Saint Cyr, 78026 Versailles, France.
| | - Anna-Sophie Fiston-Lavier
- Institut des Sciences de l'Evolution de Montpellier (ISEM), UMR5554 CNRS-Université Montpellier II, 2 place Eugene Bataillon, bat. 22, CC065 34095 Montpellier Cedex 05, France
| | - Hadi Quesneville
- Unité de recherche en Génomique-Info (URGI), UR1164, INRA, RD10 route de Saint Cyr, 78026 Versailles, France
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Hoskins RA, Carlson JW, Wan KH, Park S, Mendez I, Galle SE, Booth BW, Pfeiffer BD, George RA, Svirskas R, Krzywinski M, Schein J, Accardo MC, Damia E, Messina G, Méndez-Lago M, de Pablos B, Demakova OV, Andreyeva EN, Boldyreva LV, Marra M, Carvalho AB, Dimitri P, Villasante A, Zhimulev IF, Rubin GM, Karpen GH, Celniker SE. The Release 6 reference sequence of the Drosophila melanogaster genome. Genome Res 2015; 25:445-58. [PMID: 25589440 PMCID: PMC4352887 DOI: 10.1101/gr.185579.114] [Citation(s) in RCA: 264] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Drosophila melanogaster plays an important role in molecular,
genetic, and genomic studies of heredity, development, metabolism, behavior, and
human disease. The initial reference genome sequence reported more than a decade ago
had a profound impact on progress in Drosophila research, and
improving the accuracy and completeness of this sequence continues to be important to
further progress. We previously described improvement of the 117-Mb sequence in the
euchromatic portion of the genome and 21 Mb in the heterochromatic portion, using a
whole-genome shotgun assembly, BAC physical mapping, and clone-based finishing. Here,
we report an improved reference sequence of the single-copy and middle-repetitive
regions of the genome, produced using cytogenetic mapping to mitotic and polytene
chromosomes, clone-based finishing and BAC fingerprint verification, ordering of
scaffolds by alignment to cDNA sequences, incorporation of other map and sequence
data, and validation by whole-genome optical restriction mapping. These data
substantially improve the accuracy and completeness of the reference sequence and the
order and orientation of sequence scaffolds into chromosome arm assemblies.
Representation of the Y chromosome and other heterochromatic regions
is particularly improved. The new 143.9-Mb reference sequence, designated Release 6,
effectively exhausts clone-based technologies for mapping and sequencing. Highly
repeat-rich regions, including large satellite blocks and functional elements such as
the ribosomal RNA genes and the centromeres, are largely inaccessible to current
sequencing and assembly methods and remain poorly represented. Further significant
improvements will require sequencing technologies that do not depend on molecular
cloning and that produce very long reads.
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Affiliation(s)
- Roger A Hoskins
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA;
| | - Joseph W Carlson
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Kenneth H Wan
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Soo Park
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ivonne Mendez
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Samuel E Galle
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Benjamin W Booth
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Barret D Pfeiffer
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
| | - Reed A George
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
| | - Robert Svirskas
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
| | - Martin Krzywinski
- Genome Sciences Centre, BC Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
| | - Jacqueline Schein
- Genome Sciences Centre, BC Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
| | - Maria Carmela Accardo
- Dipartimento di Biologia e Biotecnologie "Charles Darwin" and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, 00185 Roma, Italy
| | - Elisabetta Damia
- Dipartimento di Biologia e Biotecnologie "Charles Darwin" and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, 00185 Roma, Italy
| | - Giovanni Messina
- Dipartimento di Biologia e Biotecnologie "Charles Darwin" and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, 00185 Roma, Italy
| | - María Méndez-Lago
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Beatriz de Pablos
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Olga V Demakova
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Evgeniya N Andreyeva
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Lidiya V Boldyreva
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Marco Marra
- Genome Sciences Centre, BC Cancer Agency, Vancouver, BC, V5Z 4S6, Canada
| | - A Bernardo Carvalho
- Departamento de Genética, Universidade Federal do Rio de Janeiro, CEP 21944-970, Rio de Janeiro, Brazil
| | - Patrizio Dimitri
- Dipartimento di Biologia e Biotecnologie "Charles Darwin" and Istituto Pasteur Fondazione Cenci-Bolognetti, Sapienza Università di Roma, 00185 Roma, Italy
| | - Alfredo Villasante
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Igor F Zhimulev
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Novosibirsk, 630090, Russia; Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Gerald M Rubin
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, USA
| | - Gary H Karpen
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Susan E Celniker
- Department of Genome Dynamics, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA;
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Gao D, Jiang N, Wing RA, Jiang J, Jackson SA. Transposons play an important role in the evolution and diversification of centromeres among closely related species. FRONTIERS IN PLANT SCIENCE 2015; 6:216. [PMID: 25904926 PMCID: PMC4387472 DOI: 10.3389/fpls.2015.00216] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 03/17/2015] [Indexed: 05/18/2023]
Abstract
Centromeres are important chromosomal regions necessary for eukaryotic cell segregation and replication. Due to high amounts of tandem repeats and transposons, centromeres have been difficult to sequence in most multicellular organisms, thus their sequence structure and evolution are poorly understood. In this study, we analyzed transposons in the centromere 8 (Cen8) from the African cultivated rice (O. glaberrima) and two subspecies of the Asian cultivated rice (O. sativa), indica and japonica. We detected much higher transposon contents (>69%) in centromere regions than in the whole genomes of O. sativa ssp. japonica and O. glaberrima (~35%). We compared the three Cen8s and identified numerous recent insertions of transposons that were frequently organized into multiple-layer nested blocks, similar to nested transposons in maize. Except for the Hopi retrotransposon, all LTR retrotransposons were shared but exhibit different abundances amongst the three Cen8s. Even though a majority of the transposons were located in intergenic regions, some gene-related transposons were found and may be involved in gene diversification. Chromatin immunoprecipitated (ChIP) data analysis revealed that 165 families from both Class I and Class II transposons were found in CENH3-associated chromatin sequences. These results indicate essential roles for transposons in centromeres and that the rapid divergence of the Cen8 sequences between the two cultivated rice species was primarily caused by recent transposon insertions.
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Affiliation(s)
- Dongying Gao
- Center for Applied Genetic Technologies, University of GeorgiaAthens, GA, USA
| | - Ning Jiang
- Department of Horticulture, Michigan State UniversityEast Lansing, MI, USA
| | - Rod A. Wing
- Department of Plant Sciences, Arizona Genome Institute, University of ArizonaTucson, AZ, USA
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin-MadisonMadison, WI, USA
| | - Scott A. Jackson
- Center for Applied Genetic Technologies, University of GeorgiaAthens, GA, USA
- *Correspondence: Scott A. Jackson, Center for Applied Genetic Technologies, University of Georgia, 111 Riverbend Rd, Athens, GA 30602, USA
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35
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Abstract
Since discovery of the centromere-specific histone H3 variant CENP-A, centromeres have come to be defined as chromatin structures that establish the assembly site for the complex kinetochore machinery. In most organisms, centromere activity is defined epigenetically, rather than by specific DNA sequences. In this review, we describe selected classic work and recent progress in studies of centromeric chromatin with a focus on vertebrates. We consider possible roles for repetitive DNA sequences found at most centromeres, chromatin factors and modifications that assemble and activate CENP-A chromatin for kinetochore assembly, plus the use of artificial chromosomes and kinetochores to study centromere function.
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Affiliation(s)
- Tatsuo Fukagawa
- Department of Molecular Genetics, National Institute of Genetics and Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan.
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, King's Buildings, Mayfield Road, Edinburgh, EH9 3JR, UK.
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36
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Rošić S, Köhler F, Erhardt S. Repetitive centromeric satellite RNA is essential for kinetochore formation and cell division. ACTA ACUST UNITED AC 2014; 207:335-49. [PMID: 25365994 PMCID: PMC4226727 DOI: 10.1083/jcb.201404097] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SAT III RNA binds to the kinetochore component CENP-C and is required for correct assembly and function of the kinetochore at centromeres. Chromosome segregation requires centromeres on every sister chromatid to correctly form and attach the microtubule spindle during cell division. Even though centromeres are essential for genome stability, the underlying centromeric DNA is highly variable in sequence and evolves quickly. Epigenetic mechanisms are therefore thought to regulate centromeres. Here, we show that the 359-bp repeat satellite III (SAT III), which spans megabases on the X chromosome of Drosophila melanogaster, produces a long noncoding RNA that localizes to centromeric regions of all major chromosomes. Depletion of SAT III RNA causes mitotic defects, not only of the sex chromosome but also in trans of all autosomes. We furthermore find that SAT III RNA binds to the kinetochore component CENP-C, and is required for correct localization of the centromere-defining proteins CENP-A and CENP-C, as well as outer kinetochore proteins. In conclusion, our data reveal that SAT III RNA is an integral part of centromere identity, adding RNA to the complex epigenetic mark at centromeres in flies.
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Affiliation(s)
- Silvana Rošić
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Florian Köhler
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
| | - Sylvia Erhardt
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), Deutsches Krebsforschungszentrum (DKFZ)-ZMBH Alliance, and CellNetworks Excellence Cluster, University of Heidelberg, 69120 Heidelberg, Germany
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37
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Aldrich JC, Maggert KA. Simple quantitative PCR approach to reveal naturally occurring and mutation-induced repetitive sequence variation on the Drosophila Y chromosome. PLoS One 2014; 9:e109906. [PMID: 25285439 PMCID: PMC4186871 DOI: 10.1371/journal.pone.0109906] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/13/2014] [Indexed: 02/06/2023] Open
Abstract
Heterochromatin is a significant component of the human genome and the genomes of most model organisms. Although heterochromatin is thought to be largely non-coding, it is clear that it plays an important role in chromosome structure and gene regulation. Despite a growing awareness of its functional significance, the repetitive sequences underlying some heterochromatin remain relatively uncharacterized. We have developed a real-time quantitative PCR-based method for quantifying simple repetitive satellite sequences and have used this technique to characterize the heterochromatic Y chromosome of Drosophila melanogaster. In this report, we validate the approach, identify previously unknown satellite sequence copy number polymorphisms in Y chromosomes from different geographic sources, and show that a defect in heterochromatin formation can induce similar copy number polymorphisms in a laboratory strain. These findings provide a simple method to investigate the dynamic nature of repetitive sequences and characterize conditions which might give rise to long-lasting alterations in DNA sequence.
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Affiliation(s)
- John C. Aldrich
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Keith A. Maggert
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
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38
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Centromere identity from the DNA point of view. Chromosoma 2014; 123:313-25. [PMID: 24763964 PMCID: PMC4107277 DOI: 10.1007/s00412-014-0462-0] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/28/2014] [Accepted: 04/01/2014] [Indexed: 02/05/2023]
Abstract
The centromere is a chromosomal locus responsible for the faithful segregation of genetic material during cell division. It has become evident that centromeres can be established literally on any DNA sequence, and the possible synergy between DNA sequences and the most prominent centromere identifiers, protein components, and epigenetic marks remains uncertain. However, some evolutionary preferences seem to exist, and long-term established centromeres are frequently formed on long arrays of satellite DNAs and/or transposable elements. Recent progress in understanding functional centromere sequences is based largely on the high-resolution DNA mapping of sequences that interact with the centromere-specific histone H3 variant, the most reliable marker of active centromeres. In addition, sequence assembly and mapping of large repetitive centromeric regions, as well as comparative genome analyses offer insight into their complex organization and evolution. The rapidly advancing field of transcription in centromere regions highlights the functional importance of centromeric transcripts. Here, we comprehensively review the current state of knowledge on the composition and functionality of DNA sequences underlying active centromeres and discuss their contribution to the functioning of different centromere types in higher eukaryotes.
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39
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DNA replication components as regulators of epigenetic inheritance--lesson from fission yeast centromere. Protein Cell 2014; 5:411-9. [PMID: 24691906 PMCID: PMC4026425 DOI: 10.1007/s13238-014-0049-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/24/2014] [Indexed: 01/30/2023] Open
Abstract
Genetic information stored in DNA is accurately copied and transferred to subsequent generations through DNA replication. This process is accomplished through the concerted actions of highly conserved DNA replication components. Epigenetic information stored in the form of histone modifications and DNA methylation, constitutes a second layer of regulatory information important for many cellular processes, such as gene expression regulation, chromatin organization, and genome stability. During DNA replication, epigenetic information must also be faithfully transmitted to subsequent generations. How this monumental task is achieved remains poorly understood. In this review, we will discuss recent advances on the role of DNA replication components in the inheritance of epigenetic marks, with a particular focus on epigenetic regulation in fission yeast. Based on these findings, we propose that specific DNA replication components function as key regulators in the replication of epigenetic information across the genome.
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40
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Cristancho MA, Botero-Rozo DO, Giraldo W, Tabima J, Riaño-Pachón DM, Escobar C, Rozo Y, Rivera LF, Durán A, Restrepo S, Eilam T, Anikster Y, Gaitán AL. Annotation of a hybrid partial genome of the coffee rust (Hemileia vastatrix) contributes to the gene repertoire catalog of the Pucciniales. FRONTIERS IN PLANT SCIENCE 2014; 5:594. [PMID: 25400655 PMCID: PMC4215621 DOI: 10.3389/fpls.2014.00594] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/11/2014] [Indexed: 05/20/2023]
Abstract
Coffee leaf rust caused by the fungus Hemileia vastatrix is the most damaging disease to coffee worldwide. The pathogen has recently appeared in multiple outbreaks in coffee producing countries resulting in significant yield losses and increases in costs related to its control. New races/isolates are constantly emerging as evidenced by the presence of the fungus in plants that were previously resistant. Genomic studies are opening new avenues for the study of the evolution of pathogens, the detailed description of plant-pathogen interactions and the development of molecular techniques for the identification of individual isolates. For this purpose we sequenced 8 different H. vastatrix isolates using NGS technologies and gathered partial genome assemblies due to the large repetitive content in the coffee rust hybrid genome; 74.4% of the assembled contigs harbor repetitive sequences. A hybrid assembly of 333 Mb was built based on the 8 isolates; this assembly was used for subsequent analyses. Analysis of the conserved gene space showed that the hybrid H. vastatrix genome, though highly fragmented, had a satisfactory level of completion with 91.94% of core protein-coding orthologous genes present. RNA-Seq from urediniospores was used to guide the de novo annotation of the H. vastatrix gene complement. In total, 14,445 genes organized in 3921 families were uncovered; a considerable proportion of the predicted proteins (73.8%) were homologous to other Pucciniales species genomes. Several gene families related to the fungal lifestyle were identified, particularly 483 predicted secreted proteins that represent candidate effector genes and will provide interesting hints to decipher virulence in the coffee rust fungus. The genome sequence of Hva will serve as a template to understand the molecular mechanisms used by this fungus to attack the coffee plant, to study the diversity of this species and for the development of molecular markers to distinguish races/isolates.
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Affiliation(s)
- Marco A. Cristancho
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
- *Correspondence: Marco A. Cristancho, Department of Plant Pathology, National Center for Coffee Research – CENICAFÉ, Km 4 vía a Manizales, Chinchiná 2427, Colombia e-mail:
| | - David Octavio Botero-Rozo
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
- Departamento de Ciencias Biológicas, Universidad de los AndesBogotá, Colombia
| | - William Giraldo
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
| | - Javier Tabima
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
- Departamento de Ciencias Biológicas, Universidad de los AndesBogotá, Colombia
| | | | - Carolina Escobar
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
| | - Yomara Rozo
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
| | - Luis F. Rivera
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
| | - Andrés Durán
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
| | - Silvia Restrepo
- Departamento de Ciencias Biológicas, Universidad de los AndesBogotá, Colombia
| | - Tamar Eilam
- Institute for Cereal Crops Improvement, Tel Aviv UniversityTel Aviv, Israel
| | - Yehoshua Anikster
- Institute for Cereal Crops Improvement, Tel Aviv UniversityTel Aviv, Israel
| | - Alvaro L. Gaitán
- Plant Pathology, National Center for Coffee Research – CENICAFÉChinchiná, Colombia
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Gong Z, Xue C, Liu X, Zhang M, Zhou Y, Yu H, Gu M. Centromere inactivation in a dicentric rice chromosome during sexual reproduction. CHINESE SCIENCE BULLETIN-CHINESE 2013. [DOI: 10.1007/s11434-013-6061-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Thomae AW, Schade GOM, Padeken J, Borath M, Vetter I, Kremmer E, Heun P, Imhof A. A pair of centromeric proteins mediates reproductive isolation in Drosophila species. Dev Cell 2013; 27:412-24. [PMID: 24239514 DOI: 10.1016/j.devcel.2013.10.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/26/2013] [Accepted: 10/01/2013] [Indexed: 01/09/2023]
Abstract
Speciation involves the reproductive isolation of natural populations due to the sterility or lethality of their hybrids. However, the molecular basis of hybrid lethality and the evolutionary driving forces that provoke it remain largely elusive. The hybrid male rescue (Hmr) and the lethal hybrid rescue (Lhr) genes serve as a model to study speciation in Drosophilids because their interaction causes lethality in male hybrid offspring. Here, we show that HMR and LHR form a centromeric complex necessary for proper chromosome segregation. We find that the Hmr expression level is substantially higher in Drosophila melanogaster, whereas Lhr expression levels are increased in Drosophila simulans. The resulting elevated amount of HMR/LHR complex in hybrids results in an extensive mislocalization of the complex, an interference with the regulation of transposable elements, and an impairment of cell proliferation. Our findings provide evidence for a major role of centromere divergence in the generation of biodiversity.
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Affiliation(s)
- Andreas W Thomae
- Munich Centre of Integrated Protein Science and Adolf-Butenandt Institute, Ludwig Maximilians University of Munich, 80336 Munich, Germany
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Ritland Politz JC, Scalzo D, Groudine M. Something silent this way forms: the functional organization of the repressive nuclear compartment. Annu Rev Cell Dev Biol 2013; 29:241-70. [PMID: 23834025 PMCID: PMC3999972 DOI: 10.1146/annurev-cellbio-101512-122317] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The repressive compartment of the nucleus is comprised primarily of telomeric and centromeric regions, the silent portion of ribosomal RNA genes, the majority of transposable element repeats, and facultatively repressed genes specific to different cell types. This compartment localizes into three main regions: the peripheral heterochromatin, perinucleolar heterochromatin, and pericentromeric heterochromatin. Both chromatin remodeling proteins and transcription of noncoding RNAs are involved in maintenance of repression in these compartments. Global reorganization of the repressive compartment occurs at each cell division, during early development, and during terminal differentiation. Differential action of chromatin remodeling complexes and boundary element looping activities are involved in mediating these organizational changes. We discuss the evidence that heterochromatin formation and compartmentalization may drive nuclear organization.
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Affiliation(s)
| | - David Scalzo
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Mark Groudine
- Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
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Wei L, Xiao M, An Z, Ma B, Mason AS, Qian W, Li J, Fu D. New insights into nested long terminal repeat retrotransposons in Brassica species. MOLECULAR PLANT 2013; 6:470-482. [PMID: 22930733 DOI: 10.1093/mp/sss081] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Long terminal repeat (LTR) retrotransposons, one of the foremost types of transposons, continually change or modify gene function and reorganize the genome through bursts of dramatic proliferation. Many LTR-TEs preferentially insert within other LTR-TEs, but the cause and evolutionary significance of these nested LTR-TEs are not well understood. In this study, a total of 1.52Gb of Brassica sequence containing 2020 bacterial artificial chromosomes (BACs) was scanned, and six bacterial artificial chromosome (BAC) clones with extremely nested LTR-TEs (LTR-TEs density: 7.24/kb) were selected for further analysis. The majority of the LTR-TEs in four of the six BACs were found to be derived from the rapid proliferation of retrotransposons originating within the BAC regions, with only a few LTR-TEs originating from the proliferation and insertion of retrotransposons from outside the BAC regions approximately 5-23Mya. LTR-TEs also preferably inserted into TA-rich repeat regions. Gene prediction by Genescan identified 207 genes in the 0.84Mb of total BAC sequences. Only a few genes (3/207) could be matched to the Brassica expressed sequence tag (EST) database, indicating that most genes were inactive after retrotransposon insertion. Five of the six BACs were putatively centromeric. Hence, nested LTR-TEs in centromere regions are rapidly duplicated, repeatedly inserted, and act to suppress activity of genes and to reshuffle the structure of the centromeric sequences. Our results suggest that LTR-TEs burst and proliferate on a local scale to create nested LTR-TE regions, and that these nested LTR-TEs play a role in the formation of centromeres.
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Affiliation(s)
- Lijuan Wei
- Chongqing Engineering Research Center for Rapeseed, College of Agronomy and Biotechnology, Southwest University, Chongqing 400716, China
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Smith KM, Galazka JM, Phatale PA, Connolly LR, Freitag M. Centromeres of filamentous fungi. Chromosome Res 2012; 20:635-56. [PMID: 22752455 DOI: 10.1007/s10577-012-9290-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
How centromeres are assembled and maintained remains one of the fundamental questions in cell biology. Over the past 20 years, the idea of centromeres as precise genetic loci has been replaced by the realization that it is predominantly the protein complement that defines centromere localization and function. Thus, placement and maintenance of centromeres are excellent examples of epigenetic phenomena in the strict sense. In contrast, the highly derived "point centromeres" of the budding yeast Saccharomyces cerevisiae and its close relatives are counter-examples for this general principle of centromere maintenance. While we have learned much in the past decade, it remains unclear if mechanisms for epigenetic centromere placement and maintenance are shared among various groups of organisms. For that reason, it seems prudent to examine species from many different phylogenetic groups with the aim to extract comparative information that will yield a more complete picture of cell division in all eukaryotes. This review addresses what has been learned by studying the centromeres of filamentous fungi, a large, heterogeneous group of organisms that includes important plant, animal and human pathogens, saprobes, and symbionts that fulfill essential roles in the biosphere, as well as a growing number of taxa that have become indispensable for industrial use.
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Affiliation(s)
- Kristina M Smith
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA
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46
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Na JK, Wang J, Murray JE, Gschwend AR, Zhang W, Yu Q, Navajas-Pérez R, Feltus FA, Chen C, Kubat Z, Moore PH, Jiang J, Paterson AH, Ming R. Construction of physical maps for the sex-specific regions of papaya sex chromosomes. BMC Genomics 2012; 13:176. [PMID: 22568889 PMCID: PMC3430574 DOI: 10.1186/1471-2164-13-176] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 03/12/2012] [Indexed: 12/26/2022] Open
Abstract
Background Papaya is a major fruit crop in tropical and subtropical regions worldwide. It is trioecious with three sex forms: male, female, and hermaphrodite. Sex determination is controlled by a pair of nascent sex chromosomes with two slightly different Y chromosomes, Y for male and Yh for hermaphrodite. The sex chromosome genotypes are XY (male), XYh (hermaphrodite), and XX (female). The papaya hermaphrodite-specific Yh chromosome region (HSY) is pericentromeric and heterochromatic. Physical mapping of HSY and its X counterpart is essential for sequencing these regions and uncovering the early events of sex chromosome evolution and to identify the sex determination genes for crop improvement. Results A reiterate chromosome walking strategy was applied to construct the two physical maps with three bacterial artificial chromosome (BAC) libraries. The HSY physical map consists of 68 overlapped BACs on the minimum tiling path, and covers all four HSY-specific Knobs. One gap remained in the region of Knob 1, the only knob structure shared between HSY and X, due to the lack of HSY-specific sequences. This gap was filled on the physical map of the HSY corresponding region in the X chromosome. The X physical map consists of 44 BACs on the minimum tiling path with one gap remaining in the middle, due to the nature of highly repetitive sequences. This gap was filled on the HSY physical map. The borders of the non-recombining HSY were defined genetically by fine mapping using 1460 F2 individuals. The genetically defined HSY spanned approximately 8.5 Mb, whereas its X counterpart extended about 5.4 Mb including a 900 Kb region containing the Knob 1 shared by the HSY and X. The 8.5 Mb HSY corresponds to 4.5 Mb of its X counterpart, showing 4 Mb (89%) DNA sequence expansion. Conclusion The 89% increase of DNA sequence in HSY indicates rapid expansion of the Yh chromosome after genetic recombination was suppressed 2–3 million years ago. The genetically defined borders coincide with the common BACs on the minimum tiling paths of HSY and X. The minimum tiling paths of HSY and its X counterpart are being used for sequencing these X and Yh-specific regions.
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Affiliation(s)
- Jong-Kuk Na
- Department of Plant Biology, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA
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Luo S, Mach J, Abramson B, Ramirez R, Schurr R, Barone P, Copenhaver G, Folkerts O. The cotton centromere contains a Ty3-gypsy-like LTR retroelement. PLoS One 2012; 7:e35261. [PMID: 22536361 DOI: 10.1371/journal.pone.0035261] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 03/13/2012] [Indexed: 01/16/2023] Open
Abstract
The centromere is a repeat-rich structure essential for chromosome segregation; with the long-term aim of understanding centromere structure and function, we set out to identify cotton centromere sequences. To isolate centromere-associated sequences from cotton, (Gossypium hirsutum) we surveyed tandem and dispersed repetitive DNA in the genus. Centromere-associated elements in other plants include tandem repeats and, in some cases, centromere-specific retroelements. Examination of cotton genomic survey sequences for tandem repeats yielded sequences that did not localize to the centromere. However, among the repetitive sequences we also identified a gypsy-like LTR retrotransposon (Centromere Retroelement Gossypium, CRG) that localizes to the centromere region of all chromosomes in domestic upland cotton, Gossypium hirsutum, the major commercially grown cotton. The location of the functional centromere was confirmed by immunostaining with antiserum to the centromere-specific histone CENH3, which co-localizes with CRG hybridization on metaphase mitotic chromosomes. G. hirsutum is an allotetraploid composed of A and D genomes and CRG is also present in the centromere regions of other AD cotton species. Furthermore, FISH and genomic dot blot hybridization revealed that CRG is found in D-genome diploid cotton species, but not in A-genome diploid species, indicating that this retroelement may have invaded the A-genome centromeres during allopolyploid formation and amplified during evolutionary history. CRG is also found in other diploid Gossypium species, including B and E2 genome species, but not in the C, E1, F, and G genome species tested. Isolation of this centromere-specific retrotransposon from Gossypium provides a probe for further understanding of centromere structure, and a tool for future engineering of centromere mini-chromosomes in this important crop species.
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Affiliation(s)
- Song Luo
- Chromatin, Inc., Chicago, Illinois, United States of America
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48
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Burrack LS, Berman J. Flexibility of centromere and kinetochore structures. Trends Genet 2012; 28:204-12. [PMID: 22445183 DOI: 10.1016/j.tig.2012.02.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 12/14/2022]
Abstract
Centromeres, and the kinetochores that assemble on them, are essential for accurate chromosome segregation. Diverse centromere organization patterns and kinetochore structures have evolved in eukaryotes ranging from yeast to humans. In addition, centromere DNA and kinetochore position can vary even within individual cells. This flexibility is manifested in several ways: centromere DNA sequences evolve rapidly, kinetochore positions shift in response to altered chromosome structure, and kinetochore complex numbers change in response to fluctuations in kinetochore protein levels. Despite their differences, all of these diverse structures promote efficient chromosome segregation. This robustness is inherent to chromosome segregation mechanisms and balances genome stability with adaptability. In this review, we explore the mechanisms and consequences of centromere and kinetochore flexibility as well as the benefits and limitations of different experimental model systems for their study.
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Affiliation(s)
- Laura S Burrack
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55405, USA
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49
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Zhou Q, Zhu HM, Huang QF, Zhao L, Zhang GJ, Roy SW, Vicoso B, Xuan ZL, Ruan J, Zhang Y, Zhao RP, Ye C, Zhang XQ, Wang J, Wang W, Bachtrog D. Deciphering neo-sex and B chromosome evolution by the draft genome of Drosophila albomicans. BMC Genomics 2012; 13:109. [PMID: 22439699 PMCID: PMC3353239 DOI: 10.1186/1471-2164-13-109] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 03/22/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Drosophila albomicans is a unique model organism for studying both sex chromosome and B chromosome evolution. A pair of its autosomes comprising roughly 40% of the whole genome has fused to the ancient X and Y chromosomes only about 0.12 million years ago, thereby creating the youngest and most gene-rich neo-sex system reported to date. This species also possesses recently derived B chromosomes that show non-Mendelian inheritance and significantly influence fertility. METHODS We sequenced male flies with B chromosomes at 124.5-fold genome coverage using next-generation sequencing. To characterize neo-Y specific changes and B chromosome sequences, we also sequenced inbred female flies derived from the same strain but without B's at 28.5-fold. RESULTS We assembled a female genome and placed 53% of the sequence and 85% of the annotated proteins into specific chromosomes, by comparison with the 12 Drosophila genomes. Despite its very recent origin, the non-recombining neo-Y chromosome shows various signs of degeneration, including a significant enrichment of non-functional genes compared to the neo-X, and an excess of tandem duplications relative to other chromosomes. We also characterized a B-chromosome linked scaffold that contains an actively transcribed unit and shows sequence similarity to the subcentromeric regions of both the ancient X and the neo-X chromosome. CONCLUSIONS Our results provide novel insights into the very early stages of sex chromosome evolution and B chromosome origination, and suggest an unprecedented connection between the births of these two systems in D. albomicans.
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Affiliation(s)
- Qi Zhou
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Hong-mei Zhu
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Quan-fei Huang
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Li Zhao
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Guo-jie Zhang
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Scott W Roy
- Department of Biology, Stanford University, Palo Alto, CA 94305, USA
| | - Beatriz Vicoso
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Zhao-lin Xuan
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Jue Ruan
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Yue Zhang
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Ruo-ping Zhao
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Chen Ye
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Xiu-qing Zhang
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Jun Wang
- Beijing Genomics Institute-Shenzhen, Shenzhen 518083, China
| | - Wen Wang
- CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Doris Bachtrog
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
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Tsai JH, McKee BD. Homologous pairing and the role of pairing centers in meiosis. J Cell Sci 2011; 124:1955-63. [PMID: 21625006 DOI: 10.1242/jcs.006387] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Homologous pairing establishes the foundation for accurate reductional segregation during meiosis I in sexual organisms. This Commentary summarizes recent progress in our understanding of homologous pairing in meiosis, and will focus on the characteristics and mechanisms of specialized chromosome sites, called pairing centers (PCs), in Caenorhabditis elegans and Drosophila melanogaster. In C. elegans, each chromosome contains a single PC that stabilizes chromosome pairing and initiates synapsis of homologous chromosomes. Specific zinc-finger proteins recruited to PCs link chromosomes to nuclear envelope proteins--and through them to the microtubule cytoskeleton--thereby stimulating chromosome movements in early prophase, which are thought to be important for homolog sorting. This mechanism appears to be a variant of the 'telomere bouquet' process, in which telomeres cluster on the nuclear envelope, connect chromosomes through nuclear envelope proteins to the cytoskeleton and lead chromosome movements that promote homologous synapsis. In Drosophila males, which undergo meiosis without recombination, pairing of the largely non-homologous X and Y chromosomes occurs at specific repetitive sequences in the ribosomal DNA. Although no other clear examples of PC-based pairing mechanisms have been described, there is evidence for special roles of telomeres and centromeres in aspects of chromosome pairing, synapsis and segregation; these roles are in some cases similar to those of PCs.
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Affiliation(s)
- Jui-He Tsai
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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