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Liu Y, Yi C, Fan C, Liu Q, Liu S, Shen L, Zhang K, Huang Y, Liu C, Wang Y, Tian Z, Han F. Pan-centromere reveals widespread centromere repositioning of soybean genomes. Proc Natl Acad Sci U S A 2023; 120:e2310177120. [PMID: 37816061 PMCID: PMC10589659 DOI: 10.1073/pnas.2310177120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023] Open
Abstract
Centromere repositioning refers to a de novo centromere formation at another chromosomal position without sequence rearrangement. This phenomenon was frequently encountered in both mammalian and plant species and has been implicated in genome evolution and speciation. To understand the dynamic of centromeres on soybean genome, we performed the pan-centromere analysis using CENH3-ChIP-seq data from 27 soybean accessions, including 3 wild soybeans, 9 landraces, and 15 cultivars. Building upon the previous discovery of three centromere satellites in soybean, we have identified two additional centromere satellites that specifically associate with chromosome 1. These satellites reveal significant rearrangements in the centromere structures of chromosome 1 across different accessions, consequently impacting the localization of CENH3. By comparative analysis, we reported a high frequency of centromere repositioning on 14 out of 20 chromosomes. Most newly emerging centromeres formed in close proximity to the native centromeres and some newly emerging centromeres were apparently shared in distantly related accessions, suggesting their emergence is independent. Furthermore, we crossed two accessions with mismatched centromeres to investigate how centromere positions would be influenced in hybrid genetic backgrounds. We found that a significant proportion of centromeres in the S9 generation undergo changes in size and position compared to their parental counterparts. Centromeres preferred to locate at satellites to maintain a stable state, highlighting a significant role of centromere satellites in centromere organization. Taken together, these results revealed extensive centromere repositioning in soybean genome and highlighted how important centromere satellites are in constraining centromere positions and supporting centromere function.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
| | - Congyang Yi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing100049, China
| | - Chaolan Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
| | - Qian Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing100049, China
| | - Shulin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
| | - Lisha Shen
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
| | - Kaibiao Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing100049, China
| | - Yuhong Huang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing100049, China
| | - Chang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Beijing100049, China
| | - Yingxiang Wang
- Guangdong Laboratory for Lingnan Modern Agriculture, College of Life Sciences, South China Agricultural University, Guangzhou510642, China
| | - Zhixi Tian
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing100101, China
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2
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Song JM, Xie WZ, Wang S, Guo YX, Koo DH, Kudrna D, Gong C, Huang Y, Feng JW, Zhang W, Zhou Y, Zuccolo A, Long E, Lee S, Talag J, Zhou R, Zhu XT, Yuan D, Udall J, Xie W, Wing RA, Zhang Q, Poland J, Zhang J, Chen LL. Two gap-free reference genomes and a global view of the centromere architecture in rice. MOLECULAR PLANT 2021; 14:1757-1767. [PMID: 34171480 DOI: 10.1016/j.molp.2021.06.018] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 05/04/2023]
Abstract
Rice (Oryza sativa), a major staple throughout the world and a model system for plant genomics and breeding, was the first crop genome sequenced almost two decades ago. However, reference genomes for all higher organisms to date contain gaps and missing sequences. Here, we report the assembly and analysis of gap-free reference genome sequences for two elite O. sativa xian/indica rice varieties, Zhenshan 97 and Minghui 63, which are being used as a model system for studying heterosis and yield. Gap-free reference genomes provide the opportunity for a global view of the structure and function of centromeres. We show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and structures. In addition, the similarity of CentO repeats in the same chromosome is higher than across chromosomes, supporting a model of local expansion and homogenization. Both genomes have over 395 non-TE genes located in centromere regions, of which ∼41% are actively transcribed. Two large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two genomes. The availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.
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Affiliation(s)
- Jia-Ming Song
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Wen-Zhao Xie
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Shuo Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Yi-Xiong Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Dal-Hoe Koo
- Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, USA
| | - Dave Kudrna
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Chenbo Gong
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Yicheng Huang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jia-Wu Feng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenhui Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Yong Zhou
- Center for Desert Agriculture, Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Andrea Zuccolo
- Center for Desert Agriculture, Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Evan Long
- Plant and Wildlife Science Department, Brigham Young University, Provo, UT 84602, USA
| | - Seunghee Lee
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Jayson Talag
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Run Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Xi-Tong Zhu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Daojun Yuan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Joshua Udall
- Plant and Wildlife Science Department, Brigham Young University, Provo, UT 84602, USA
| | - Weibo Xie
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Rod A Wing
- Arizona Genomics Institute, School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA; Center for Desert Agriculture, Biological and Environmental Sciences & Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia; International Rice Research Institute (IRRI), Strategic Innovation, Los Baños, 4031 Laguna, Philippines
| | - Qifa Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jesse Poland
- Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, Manhattan, KS, USA.
| | - Jianwei Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ling-Ling Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Life Science and Technology, Guangxi University, Nanning 530004, China.
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3
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Garrido-Ramos MA. The Genomics of Plant Satellite DNA. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 60:103-143. [PMID: 34386874 DOI: 10.1007/978-3-030-74889-0_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The twenty-first century began with a certain indifference to the research of satellite DNA (satDNA). Neither genome sequencing projects were able to accurately encompass the study of satDNA nor classic methodologies were able to go further in undertaking a better comprehensive study of the whole set of satDNA sequences of a genome. Nonetheless, knowledge of satDNA has progressively advanced during this century with the advent of new analytical techniques. The enormous advantages that genome-wide approaches have brought to its analysis have now stimulated a renewed interest in the study of satDNA. At this point, we can look back and try to assess more accurately many of the key questions that were left unsolved in the past about this enigmatic and important component of the genome. I review here the understanding gathered on plant satDNAs over the last few decades with an eye on the near future.
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Wang N, Liu J, Ricci WA, Gent JI, Dawe RK. Maize centromeric chromatin scales with changes in genome size. Genetics 2021; 217:iyab020. [PMID: 33857306 PMCID: PMC8049547 DOI: 10.1093/genetics/iyab020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/30/2021] [Indexed: 11/14/2022] Open
Abstract
Centromeres are defined by the location of Centromeric Histone H3 (CENP-A/CENH3) which interacts with DNA to define the locations and sizes of functional centromeres. An analysis of 26 maize genomes including 110 fully assembled centromeric regions revealed positive relationships between centromere size and genome size. These effects are independent of variation in the amounts of the major centromeric satellite sequence CentC. We also backcrossed known centromeres into two different lines with larger genomes and observed consistent increases in functional centromere sizes for multiple centromeres. Although changes in centromere size involve changes in bound CENH3, we could not mimic the effect by overexpressing CENH3 by threefold. Literature from other fields demonstrate that changes in genome size affect protein levels, organelle size and cell size. Our data demonstrate that centromere size is among these scalable features, and that multiple limiting factors together contribute to a stable centromere size equilibrium.
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Affiliation(s)
- Na Wang
- Department of Plant Biology, University of Georgia, Athens GA 30602, USA
| | - Jianing Liu
- Department of Genetics, University of Georgia, Athens GA 30602, USA
| | - William A Ricci
- Department of Plant Biology, University of Georgia, Athens GA 30602, USA
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens GA 30602, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens GA 30602, USA
- Department of Genetics, University of Georgia, Athens GA 30602, USA
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5
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Multiple wheat genomes reveal global variation in modern breeding. Nature 2020; 588:277-283. [PMID: 33239791 PMCID: PMC7759465 DOI: 10.1038/s41586-020-2961-x] [Citation(s) in RCA: 387] [Impact Index Per Article: 96.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/09/2020] [Indexed: 12/24/2022]
Abstract
Advances in genomics have expedited the improvement of several agriculturally important crops but similar efforts in wheat (Triticum spp.) have been more challenging. This is largely owing to the size and complexity of the wheat genome1, and the lack of genome-assembly data for multiple wheat lines2,3. Here we generated ten chromosome pseudomolecule and five scaffold assemblies of hexaploid wheat to explore the genomic diversity among wheat lines from global breeding programs. Comparative analysis revealed extensive structural rearrangements, introgressions from wild relatives and differences in gene content resulting from complex breeding histories aimed at improving adaptation to diverse environments, grain yield and quality, and resistance to stresses4,5. We provide examples outlining the utility of these genomes, including a detailed multi-genome-derived nucleotide-binding leucine-rich repeat protein repertoire involved in disease resistance and the characterization of Sm16, a gene associated with insect resistance. These genome assemblies will provide a basis for functional gene discovery and breeding to deliver the next generation of modern wheat cultivars. Comparison of multiple genome assemblies from wheat reveals extensive diversity that results from the complex breeding history of wheat and provides a basis for further potential improvements to this important food crop.
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Feng C, Yuan J, Bai H, Liu Y, Su H, Liu Y, Shi L, Gao Z, Birchler JA, Han F. The deposition of CENH3 in maize is stringently regulated. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:6-17. [PMID: 31713923 DOI: 10.1111/tpj.14606] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 05/25/2023]
Abstract
The centromere, as an essential element to mediate chromosome segregation, is epigenetically determined by CENH3-containing nucleosomes as a functional marker; therefore the accurate deposition of CENH3 is crucial for chromosome transmission. We characterized the deposition of CENH3 in maize by over-expression and mutational analysis. Our results revealed that over-expressing CENH3 in callus is lethal while over-expressing GFP-CENH3 and CENH3-YFP in callus and plants is not and can be partly deposited normally. Different mutations of GFP-CENH3 demonstrated that CENH3-Thr4 in the N-terminus was needed for the deposition as a positive phosphorylation site and the last five amino acids in the C-terminus are necessary for deposition. The C-terminal tail of CENH3 is confirmed to be responsible for the interaction of CENH3 and histone H4, which indicates that CENH3 maintains deposition in centromeres via interacting with H4 to form stable nucleosomes. For GFP-CENH3 and CENH3-YFP, the fused tags at the termini probably affect the structure of CENH3 and reduce its interaction with other proteins, which in turn could decrease proper deposition. Taken together, multiple amino acids or motifs were shown to play essential roles in CENH3 deposition, which is suggested to be affected by numerous factors in maize.
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Affiliation(s)
- Chao Feng
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Yuan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Han Bai
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yalin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lindan Shi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhi Gao
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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7
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Liao Y, Zhang X, Li B, Liu T, Chen J, Bai Z, Wang M, Shi J, Walling JG, Wing RA, Jiang J, Chen M. Comparison of Oryza sativa and Oryza brachyantha Genomes Reveals Selection-Driven Gene Escape from the Centromeric Regions. THE PLANT CELL 2018; 30:1729-1744. [PMID: 29967288 PMCID: PMC6139686 DOI: 10.1105/tpc.18.00163] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/23/2018] [Accepted: 06/28/2018] [Indexed: 05/03/2023]
Abstract
Centromeres are dynamic chromosomal regions, and the genetic and epigenetic environment of the centromere is often regarded as oppressive to protein-coding genes. Here, we used comparative genomic and phylogenomic approaches to study the evolution of centromeres and centromere-linked genes in the genus Oryza We report a 12.4-Mb high-quality BAC-based pericentromeric assembly for Oryza brachyantha, which diverged from cultivated rice (Oryza sativa) ∼15 million years ago. The synteny analyses reveal seven medium (>50 kb) pericentric inversions in O. sativa and 10 in O. brachyantha Of these inversions, three resulted in centromere movement (Chr1, Chr7, and Chr9). Additionally, we identified a potential centromere-repositioning event, in which the ancestral centromere on chromosome 12 in O. brachyantha jumped ∼400 kb away, possibly mediated by a duplicated transposition event (>28 kb). More strikingly, we observed an excess of syntenic gene loss at and near the centromeric regions (P < 2.2 × 10-16). Most (33/47) of the missing genes moved to other genomic regions; therefore such excess could be explained by the selective loss of the copy in or near centromeric regions after gene duplication. The pattern of gene loss immediately adjacent to centromeric regions suggests centromere chromatin dynamics (e.g., spreading or microrepositioning) may drive such gene loss.
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Affiliation(s)
- Yi Liao
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xuemei Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bo Li
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tieyan Liu
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinfeng Chen
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zetao Bai
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Meijiao Wang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jinfeng Shi
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jason G Walling
- USDA-ARS-MWA-Cereal Crops Research Unit, Madison, Wisconsin 53726
| | - Rod A Wing
- Arizona Genomics Institute, School of Plant Sciences, BIO5 Institute, University of Arizona, Tucson, Arizona 85721
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin-Madison, Madison, Wisconsin 53706
- Department of Plant Biology, Department of Horticulture, Michigan State University, East Lansing, Michigan 48824
| | - Mingsheng Chen
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing, China
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8
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Wang N, Dawe RK. Centromere Size and Its Relationship to Haploid Formation in Plants. MOLECULAR PLANT 2018; 11:398-406. [PMID: 29277426 DOI: 10.1016/j.molp.2017.12.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/07/2017] [Accepted: 12/12/2017] [Indexed: 05/18/2023]
Abstract
Wide species crosses often result in uniparental genome elimination and visible failures in centromere function. Crosses involving lines with mutated forms of the CENH3 histone variant that organizes the centromere/kinetochore interface have been shown to have similar effects, inducing haploids at high frequencies. Here, we propose a simple centromere size model that endeavors to explain both observations. It is based on the idea of a quantitative centromere architecture where each centromere in an individual is the same size, and the average size is dictated by a natural equilibrium between bound and unbound CENH3 (and its chaperones or binding proteins). While centromere size is determined by the cellular milieu, centromere positions are heritable and defined by the interactions of a small set of proteins that bind to both DNA and CENH3. Lines with defective or mutated CENH3 have a lower loading capacity and support smaller centromeres. In cases where a line with small or defective centromeres is crossed to a line with larger or normal centromeres, the smaller/defective centromeres are selectively degraded or not maintained, resulting in chromosome loss from the small-centromere parent. The model is testable and generalizable, and helps to explain the counterintuitive observation that inducer lines do not induce haploids when crossed to themselves.
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Affiliation(s)
- Na Wang
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA; Department of Genetics, University of Georgia, Athens, GA 30602, USA.
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9
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Wear EE, Song J, Zynda GJ, LeBlanc C, Lee TJ, Mickelson-Young L, Concia L, Mulvaney P, Szymanski ES, Allen GC, Martienssen RA, Vaughn MW, Hanley-Bowdoin L, Thompson WF. Genomic Analysis of the DNA Replication Timing Program during Mitotic S Phase in Maize ( Zea mays) Root Tips. THE PLANT CELL 2017; 29:2126-2149. [PMID: 28842533 PMCID: PMC5635974 DOI: 10.1105/tpc.17.00037] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/31/2017] [Accepted: 08/24/2017] [Indexed: 05/19/2023]
Abstract
All plants and animals must replicate their DNA, using a regulated process to ensure that their genomes are completely and accurately replicated. DNA replication timing programs have been extensively studied in yeast and animal systems, but much less is known about the replication programs of plants. We report a novel adaptation of the "Repli-seq" assay for use in intact root tips of maize (Zea mays) that includes several different cell lineages and present whole-genome replication timing profiles from cells in early, mid, and late S phase of the mitotic cell cycle. Maize root tips have a complex replication timing program, including regions of distinct early, mid, and late S replication that each constitute between 20 and 24% of the genome, as well as other loci corresponding to ∼32% of the genome that exhibit replication activity in two different time windows. Analyses of genomic, transcriptional, and chromatin features of the euchromatic portion of the maize genome provide evidence for a gradient of early replicating, open chromatin that transitions gradually to less open and less transcriptionally active chromatin replicating in mid S phase. Our genomic level analysis also demonstrated that the centromere core replicates in mid S, before heavily compacted classical heterochromatin, including pericentromeres and knobs, which replicate during late S phase.
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Affiliation(s)
- Emily E Wear
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Jawon Song
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Gregory J Zynda
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Chantal LeBlanc
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Tae-Jin Lee
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Leigh Mickelson-Young
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Lorenzo Concia
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Patrick Mulvaney
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - Eric S Szymanski
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - George C Allen
- Department of Horticultural Science, North Carolina State University, Raleigh, North Carolina 27695
| | | | - Matthew W Vaughn
- Texas Advanced Computing Center, University of Texas, Austin, Texas 78758
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
| | - William F Thompson
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695
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10
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Jiao Y, Peluso P, Shi J, Liang T, Stitzer MC, Wang B, Campbell MS, Stein JC, Wei X, Chin CS, Guill K, Regulski M, Kumari S, Olson A, Gent J, Schneider KL, Wolfgruber TK, May MR, Springer NM, Antoniou E, McCombie WR, Presting GG, McMullen M, Ross-Ibarra J, Dawe RK, Hastie A, Rank DR, Ware D. Improved maize reference genome with single-molecule technologies. Nature 2017; 546:524-527. [PMID: 28605751 DOI: 10.1101/079004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 05/14/2017] [Indexed: 05/21/2023]
Abstract
Complete and accurate reference genomes and annotations provide fundamental tools for characterization of genetic and functional variation. These resources facilitate the determination of biological processes and support translation of research findings into improved and sustainable agricultural technologies. Many reference genomes for crop plants have been generated over the past decade, but these genomes are often fragmented and missing complex repeat regions. Here we report the assembly and annotation of a reference genome of maize, a genetic and agricultural model species, using single-molecule real-time sequencing and high-resolution optical mapping. Relative to the previous reference genome, our assembly features a 52-fold increase in contig length and notable improvements in the assembly of intergenic spaces and centromeres. Characterization of the repetitive portion of the genome revealed more than 130,000 intact transposable elements, allowing us to identify transposable element lineage expansions that are unique to maize. Gene annotations were updated using 111,000 full-length transcripts obtained by single-molecule real-time sequencing. In addition, comparative optical mapping of two other inbred maize lines revealed a prevalence of deletions in regions of low gene density and maize lineage-specific genes.
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Affiliation(s)
- Yinping Jiao
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Paul Peluso
- Pacific Biosciences, Menlo Park, California 94025, USA
| | - Jinghua Shi
- BioNano Genomics, San Diego, California 92121, USA
| | | | - Michelle C Stitzer
- Department of Plant Sciences and Center for Population Biology, University of California, Davis, Davis, California 95616, USA
| | - Bo Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | - Joshua C Stein
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Xuehong Wei
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | - Katherine Guill
- USDA-ARS, Plant Genetics Research Unit, Columbia, Missouri 65211, USA
| | - Michael Regulski
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Sunita Kumari
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Andrew Olson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | - Kevin L Schneider
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii 96822, USA
| | - Thomas K Wolfgruber
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii 96822, USA
| | - Michael R May
- Department of Evolution and Ecology, University of California, Davis, California 95616, USA
| | - Nathan M Springer
- Department of Plant Biology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Eric Antoniou
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | - Gernot G Presting
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii 96822, USA
| | - Michael McMullen
- USDA-ARS, Plant Genetics Research Unit, Columbia, Missouri 65211, USA
| | - Jeffrey Ross-Ibarra
- Department of Plant Sciences, Center for Population Biology, and Genome Center, University of California, Davis, California 95616, USA
| | - R Kelly Dawe
- University of Georgia, Athens, Georgia 30602, USA
| | - Alex Hastie
- BioNano Genomics, San Diego, California 92121, USA
| | - David R Rank
- Pacific Biosciences, Menlo Park, California 94025, USA
| | - Doreen Ware
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
- USDA-ARS, NEA Robert W. Holley Center for Agriculture and Health, Cornell University, Ithaca, New York 14853, USA
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11
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Gent JI, Wang N, Dawe RK. Stable centromere positioning in diverse sequence contexts of complex and satellite centromeres of maize and wild relatives. Genome Biol 2017. [PMID: 28637491 PMCID: PMC5480163 DOI: 10.1186/s13059-017-1249-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background Paradoxically, centromeres are known both for their characteristic repeat sequences (satellite DNA) and for being epigenetically defined. Maize (Zea mays mays) is an attractive model for studying centromere positioning because many of its large (~2 Mb) centromeres are not dominated by satellite DNA. These centromeres, which we call complex centromeres, allow for both assembly into reference genomes and for mapping short reads from ChIP-seq with antibodies to centromeric histone H3 (cenH3). Results We found frequent complex centromeres in maize and its wild relatives Z. mays parviglumis, Z. mays mexicana, and particularly Z. mays huehuetenangensis. Analysis of individual plants reveals minor variation in the positions of complex centromeres among siblings. However, such positional shifts are stochastic and not heritable, consistent with prior findings that centromere positioning is stable at the population level. Centromeres are also stable in multiple F1 hybrid contexts. Analysis of repeats in Z. mays and other species (Zea diploperennis, Zea luxurians, and Tripsacum dactyloides) reveals tenfold differences in abundance of the major satellite CentC, but similar high levels of sequence polymorphism in individual CentC copies. Deviation from the CentC consensus has little or no effect on binding of cenH3. Conclusions These data indicate that complex centromeres are neither a peculiarity of cultivation nor inbreeding in Z. mays. While extensive arrays of CentC may be the norm for other Zea and Tripsacum species, these data also reveal that a wide diversity of DNA sequences and multiple types of genetic elements in and near centromeres support centromere function and constrain centromere positions. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1249-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, USA
| | - Na Wang
- Department of Plant Biology, University of Georgia, Athens, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, USA. .,Department of Genetics, University of Georgia, Athens, USA.
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12
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Improved maize reference genome with single-molecule technologies. Nature 2017; 546:524-527. [PMID: 28605751 PMCID: PMC7052699 DOI: 10.1038/nature22971] [Citation(s) in RCA: 693] [Impact Index Per Article: 99.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 05/14/2017] [Indexed: 01/01/2023]
Abstract
An improved reference genome for maize, using single-molecule sequencing and high-resolution optical mapping, enables characterization of structural variation and repetitive regions, and identifies lineage expansions of transposable elements that are unique to maize. The maize genome was initially reported in 2009 but with some accuracy limitations. Doreen Ware and colleagues report a new reference genome for maize using single-molecule sequencing and high-resolution optical mapping. The technique shows improvements in the gene space including resolution of gaps and misassemblies and correction of order and orientation of genes. The authors characterize structural variation and repetitive regions, and identify transposable element lineage expansions unique to maize. Complete and accurate reference genomes and annotations provide fundamental tools for characterization of genetic and functional variation1. These resources facilitate the determination of biological processes and support translation of research findings into improved and sustainable agricultural technologies. Many reference genomes for crop plants have been generated over the past decade, but these genomes are often fragmented and missing complex repeat regions2. Here we report the assembly and annotation of a reference genome of maize, a genetic and agricultural model species, using single-molecule real-time sequencing and high-resolution optical mapping. Relative to the previous reference genome3, our assembly features a 52-fold increase in contig length and notable improvements in the assembly of intergenic spaces and centromeres. Characterization of the repetitive portion of the genome revealed more than 130,000 intact transposable elements, allowing us to identify transposable element lineage expansions that are unique to maize. Gene annotations were updated using 111,000 full-length transcripts obtained by single-molecule real-time sequencing4. In addition, comparative optical mapping of two other inbred maize lines revealed a prevalence of deletions in regions of low gene density and maize lineage-specific genes.
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13
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Comai L, Maheshwari S, Marimuthu MPA. Plant centromeres. CURRENT OPINION IN PLANT BIOLOGY 2017; 36:158-167. [PMID: 28411416 DOI: 10.1016/j.pbi.2017.03.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 05/24/2023]
Abstract
Plant centromeres, which are determined epigenetically by centromeric histone 3 (CENH3) have revealed surprising structural diversity, ranging from the canonical monocentric seen in vertebrates, to polycentric, and holocentric. Normally stable, centromeres can change position over evolutionary times or upon genomic stress, such as when chromosomes are broken. At the DNA level, centromeres can be based on single copy DNA or more commonly on repeats. Rapid evolution of centromeric sequences and of CENH3 protein remains a mystery, as evidence of co-adaptation is lacking. Epigenetic differences between parents can trigger uniparental centromere failure and genome elimination, contributing to postzygotic hybridization barriers..
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Affiliation(s)
- Luca Comai
- Department of Plant Biology and Genome Center, University of California Davis, Davis, CA 95616, USA.
| | - Shamoni Maheshwari
- Department of Plant Biology and Genome Center, University of California Davis, Davis, CA 95616, USA
| | - Mohan P A Marimuthu
- Department of Plant Biology and Genome Center, University of California Davis, Davis, CA 95616, USA
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14
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Isolation and characterization of centromeric repetitive DNA sequences in Saccharum spontaneum. Sci Rep 2017; 7:41659. [PMID: 28134354 PMCID: PMC5278356 DOI: 10.1038/srep41659] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/21/2016] [Indexed: 01/05/2023] Open
Abstract
Sugarcane (Saccharum hybrids spp.) is the most important sugar crop that accounts for ~75% of the world’s sugar production. Recently, a whole-genome sequencing project was launched on the wild species S. spontaneum. To obtain information on the DNA composition of the repeat-enriched region of the centromere, we conducted a genome-wide analysis of the DNA sequences associated with CenH3 (a mutant of histone H3 located in eukaryote centromeres) using chromatin immunoprecipitation followed by sequencing (ChIP-seq) method. We demonstrate that the centromeres contain mainly SCEN-like single satellite repeat (Ss1) and several Ty3/gypsy retrotransposon-related repeats (Ss166, Ss51, and Ss68). Ss1 dominates in the centromeric regions and spans up to 500 kb. In contrast, the Ty3/gypsy retrotransposon-related repeats are either clustered spanning over a short range, or dispersed in the centromere regions. Interestingly, Ss1 exhibits a chromosome-specific enrichment in the wild species S. spontaneum and S. robustum, but not in the domesticated species S. officinarum and modern sugarcane cultivars. This finding suggests an autopolyploid genome identity of S. spontaneum with a high level of homology among its eight sub-genomes. We also conducted a genome-wide survey of the repetitive DNAs in S. spontaneum following a similarity-based sequence clustering strategy. These results provide insight into the composition of sugarcane genome as well as the genome assembly of S. spontaneum.
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15
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Hori T, Kagawa N, Toyoda A, Fujiyama A, Misu S, Monma N, Makino F, Ikeo K, Fukagawa T. Constitutive centromere-associated network controls centromere drift in vertebrate cells. J Cell Biol 2016; 216:101-113. [PMID: 27940888 PMCID: PMC5223601 DOI: 10.1083/jcb.201605001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 09/12/2016] [Accepted: 11/11/2016] [Indexed: 01/28/2023] Open
Abstract
Hori et al. show that centromere position can be drifted during cell proliferation in chicken DT40 cells. However, the centromere drift is suppressed in short-term cultures, and a complete constitutive centromere-associated network organization contributes to the suppression of the centromere drift. Centromeres are specified by sequence-independent epigenetic mechanisms, and the centromere position may drift at each cell cycle, but once this position is specified, it may not be frequently moved. Currently, it is unclear whether the centromere position is stable. To address this question, we systematically analyzed the position of nonrepetitive centromeres in 21 independent clones isolated from a laboratory stock of chicken DT40 cells using chromatin immunoprecipitation combined with massive parallel sequencing analysis with anti–CENP-A antibody. We demonstrated that the centromere position varies among the clones, suggesting that centromere drift occurs during cell proliferation. However, when we analyzed this position in the subclones obtained from one isolated clone, the position was found to be relatively stable. Interestingly, the centromere drift was shown to occur frequently in CENP-U– and CENP-S–deficient cells. Based on these results, we suggest that the centromere position can change after many cell divisions, but this drift is suppressed in short-term cultures, and the complete centromere structure contributes to the suppression of the centromere drift.
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Affiliation(s)
- Tetsuya Hori
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Naoko Kagawa
- Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.,National Institute of Informatics, Chiyoda-ku, Tokyo 101-8430, Japan
| | - Sadahiko Misu
- DNA Data Analysis Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Norikazu Monma
- DNA Data Analysis Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Fumiaki Makino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuho Ikeo
- DNA Data Analysis Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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16
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Kowar T, Zakrzewski F, Macas J, Kobližková A, Viehoever P, Weisshaar B, Schmidt T. Repeat Composition of CenH3-chromatin and H3K9me2-marked heterochromatin in Sugar Beet (Beta vulgaris). BMC PLANT BIOLOGY 2016; 16:120. [PMID: 27230558 PMCID: PMC4881148 DOI: 10.1186/s12870-016-0805-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 05/17/2016] [Indexed: 05/18/2023]
Abstract
BACKGROUND Sugar beet (Beta vulgaris) is an important crop of temperate climate zones, which provides nearly 30 % of the world's annual sugar needs. From the total genome size of 758 Mb, only 567 Mb were incorporated in the recently published genome sequence, due to the fact that regions with high repetitive DNA contents (e.g. satellite DNAs) are only partially included. Therefore, to fill these gaps and to gain information about the repeat composition of centromeres and heterochromatic regions, we performed chromatin immunoprecipitation followed by sequencing (ChIP-Seq) using antibodies against the centromere-specific histone H3 variant of sugar beet (CenH3) and the heterochromatic mark of dimethylated lysine 9 of histone H3 (H3K9me2). RESULTS ChIP-Seq analysis revealed that active centromeres containing CenH3 consist of the satellite pBV and the Ty3-gypsy retrotransposon Beetle7, while heterochromatin marked by H3K9me2 exhibits heterogeneity in repeat composition. H3K9me2 was mainly associated with the satellite family pEV, the Ty1-copia retrotransposon family Cotzilla and the DNA transposon superfamily of the En/Spm type. In members of the section Beta within the genus Beta, immunostaining using the CenH3 antibody was successful, indicating that orthologous CenH3 proteins are present in closely related species within this section. CONCLUSIONS The identification of repetitive genome portions by ChIP-Seq experiments complemented the sugar beet reference sequence by providing insights into the repeat composition of poorly characterized CenH3-chromatin and H3K9me2-heterochromatin. Therefore, our work provides the basis for future research and application concerning the sugar beet centromere and repeat-rich heterochromatic regions characterized by the presence of H3K9me2.
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Affiliation(s)
- Teresa Kowar
- Department of Plant Cell and Molecular Biology, TU Dresden, Dresden, D-01062, Germany
| | - Falk Zakrzewski
- Department of Plant Cell and Molecular Biology, TU Dresden, Dresden, D-01062, Germany
| | - Jiří Macas
- Biology Centre ASCR, Institute of Plant Molecular Biology, Branišovská 31, Česke Budějovice, CZ-37005, Czech Republic
| | - Andrea Kobližková
- Biology Centre ASCR, Institute of Plant Molecular Biology, Branišovská 31, Česke Budějovice, CZ-37005, Czech Republic
| | - Prisca Viehoever
- CeBiTec & Faculty of Biology, Bielefeld University, Universitätsstr. 25, Bielefeld, D-33615, Germany
| | - Bernd Weisshaar
- CeBiTec & Faculty of Biology, Bielefeld University, Universitätsstr. 25, Bielefeld, D-33615, Germany.
| | - Thomas Schmidt
- Department of Plant Cell and Molecular Biology, TU Dresden, Dresden, D-01062, Germany
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17
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Zhao H, Zhu X, Wang K, Gent JI, Zhang W, Dawe RK, Jiang J. Gene Expression and Chromatin Modifications Associated with Maize Centromeres. G3 (BETHESDA, MD.) 2015; 6:183-92. [PMID: 26564952 PMCID: PMC4704717 DOI: 10.1534/g3.115.022764] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/09/2015] [Indexed: 12/23/2022]
Abstract
Centromeres are defined by the presence of CENH3, a variant of histone H3. Centromeres in most plant species contain exclusively highly repetitive DNA sequences, which has hindered research on structure and function of centromeric chromatin. Several maize centromeres have been nearly completely sequenced, providing a sequence-based platform for genomic and epigenomic research of plant centromeres. Here we report a high resolution map of CENH3 nucleosomes in the maize genome. Although CENH3 nucleosomes are spaced ∼190 bp on average, CENH3 nucleosomes that occupied CentC, a 156-bp centromeric satellite repeat, showed clear positioning aligning with CentC monomers. Maize centromeres contain alternating CENH3-enriched and CENH3-depleted subdomains, which account for 87% and 13% of the centromeres, respectively. A number of annotated genes were identified in the centromeres, including 11 active genes that were located exclusively in CENH3-depleted subdomains. The euchromatic histone modification marks, including H3K4me3, H3K36me3 and H3K9ac, detected in maize centromeres were associated mainly with the active genes. Interestingly, maize centromeres also have lower levels of the heterochromatin histone modification mark H3K27me2 relative to pericentromeric regions. We conclude that neither H3K27me2 nor the three euchromatic histone modifications are likely to serve as functionally important epigenetic marks of centromere identity in maize.
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Affiliation(s)
- Hainan Zhao
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Xiaobiao Zhu
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Kai Wang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602
| | - Wenli Zhang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602
| | - Jiming Jiang
- Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706
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18
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Generation of a Maize B Centromere Minimal Map Containing the Central Core Domain. G3-GENES GENOMES GENETICS 2015; 5:2857-64. [PMID: 26511496 PMCID: PMC4683656 DOI: 10.1534/g3.115.022889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The maize B centromere has been used as a model for centromere epigenetics and as the basis for building artificial chromosomes. However, there are no sequence resources for this important centromere. Here we used transposon display for the centromere-specific retroelement CRM2 to identify a collection of 40 sequence tags that flank CRM2 insertion points on the B chromosome. These were confirmed to lie within the centromere by assaying deletion breakpoints from centromere misdivision derivatives (intracentromere breakages caused by centromere fission). Markers were grouped together on the basis of their association with other markers in the misdivision series and assembled into a pseudocontig containing 10.1 kb of sequence. To identify sequences that interact directly with centromere proteins, we carried out chromatin immunoprecipitation using antibodies to centromeric histone H3 (CENH3), a defining feature of functional centromeric sequences. The CENH3 chromatin immunoprecipitation map was interpreted relative to the known transmission rates of centromere misdivision derivatives to identify a centromere core domain spanning 33 markers. A subset of seven markers was mapped in additional B centromere misdivision derivatives with the use of unique primer pairs. A derivative previously shown to have no canonical centromere sequences (Telo3-3) lacks these core markers. Our results provide a molecular map of the B chromosome centromere and identify key sequences within the map that interact directly with centromeric histone H3.
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