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Kitaoka M, Smith OK, Straight AF, Heald R. Molecular conflicts disrupting centromere maintenance contribute to Xenopus hybrid inviability. Curr Biol 2022; 32:3939-3951.e6. [PMID: 35973429 PMCID: PMC9529917 DOI: 10.1016/j.cub.2022.07.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 06/15/2022] [Accepted: 07/15/2022] [Indexed: 11/22/2022]
Abstract
Although central to evolution, the causes of hybrid inviability that drive reproductive isolation are poorly understood. Embryonic lethality occurs when the eggs of the frog X. tropicalis are fertilized with either X. laevis or X. borealis sperm. We observed that distinct subsets of paternal chromosomes failed to assemble functional centromeres, causing their mis-segregation during embryonic cell divisions. Core centromere DNA sequence analysis revealed little conservation among the three species, indicating that epigenetic mechanisms that normally operate to maintain centromere integrity are disrupted on specific paternal chromosomes in hybrids. In vitro reactions combining X. tropicalis egg extract with either X. laevis or X. borealis sperm chromosomes revealed that paternally matched or overexpressed centromeric histone CENP-A and its chaperone HJURP could rescue centromere assembly on affected chromosomes in interphase nuclei. However, although the X. laevis chromosomes maintained centromeric CENP-A in metaphase, X. borealis chromosomes did not and also displayed ultra-thin regions containing ribosomal DNA. Both centromere assembly and morphology of X. borealis mitotic chromosomes could be rescued by inhibiting RNA polymerase I or preventing the collapse of stalled DNA replication forks. These results indicate that specific paternal centromeres are inactivated in hybrids due to the disruption of associated chromatin regions that interfere with CENP-A incorporation, at least in some cases due to conflicts between replication and transcription machineries. Thus, our findings highlight the dynamic nature of centromere maintenance and its susceptibility to disruption in vertebrate interspecies hybrids.
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Affiliation(s)
- Maiko Kitaoka
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Owen K Smith
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA
| | - Aaron F Straight
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA
| | - Rebecca Heald
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA.
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2
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Brändle F, Frühbauer B, Jagannathan M. Principles and functions of pericentromeric satellite DNA clustering into chromocenters. Semin Cell Dev Biol 2022; 128:26-39. [PMID: 35144860 DOI: 10.1016/j.semcdb.2022.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/03/2022] [Accepted: 02/03/2022] [Indexed: 12/29/2022]
Abstract
Simple non-coding tandem repeats known as satellite DNA are observed widely across eukaryotes. These repeats occupy vast regions at the centromere and pericentromere of chromosomes but their contribution to cellular function has remained incompletely understood. Here, we review the literature on pericentromeric satellite DNA and discuss its organization and functions across eukaryotic species. We specifically focus on chromocenters, DNA-dense nuclear foci that contain clustered pericentromeric satellite DNA repeats from multiple chromosomes. We first discuss chromocenter formation and the roles that epigenetic modifications, satellite DNA transcripts and sequence-specific satellite DNA-binding play in this process. We then review the newly emerging functions of chromocenters in genome encapsulation, the maintenance of cell fate and speciation. We specifically highlight how the rapid divergence of satellite DNA repeats impacts reproductive isolation between closely related species. Together, we underline the importance of this so-called 'junk DNA' in fundamental biological processes.
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Affiliation(s)
- Franziska Brändle
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Benjamin Frühbauer
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland
| | - Madhav Jagannathan
- Institute of Biochemistry, ETH Zürich, Otto-Stern-Weg 3, Zürich CH-8093, Switzerland.
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3
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Jagannathan M, Yamashita YM. Defective Satellite DNA Clustering into Chromocenters Underlies Hybrid Incompatibility in Drosophila. Mol Biol Evol 2021; 38:4977-4986. [PMID: 34302471 PMCID: PMC8557456 DOI: 10.1093/molbev/msab221] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Although rapid evolution of pericentromeric satellite DNA repeats is theorized to promote hybrid incompatibility (HI) (Yunis and Yasmineh 1971; Henikoff et al. 2001; Ferree and Barbash 2009; Sawamura 2012; Jagannathan and Yamashita 2017), how divergent repeats affect hybrid cells remains poorly understood. Recently, we demonstrated that sequence-specific DNA-binding proteins cluster satellite DNA from multiple chromosomes into "chromocenters," thereby bundling chromosomes to maintain the entire genome in a single nucleus (Jagannathan et al. 2018, 2019). Here, we show that ineffective clustering of divergent satellite DNA in the cells of Drosophila hybrids results in chromocenter disruption, associated micronuclei formation, and tissue atrophy. We further demonstrate that previously identified HI factors trigger chromocenter disruption and micronuclei in hybrids, linking their function to a conserved cellular process. Together, we propose a unifying framework that explains how the widely observed satellite DNA divergence between closely related species can cause reproductive isolation.
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Affiliation(s)
| | - Yukiko M Yamashita
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Whitehead Institute and Department of Biology, MIT, Cambridge, MA, USA
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4
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Lukacs A, Thomae AW, Krueger P, Schauer T, Venkatasubramani AV, Kochanova NY, Aftab W, Choudhury R, Forne I, Imhof A. The Integrity of the HMR complex is necessary for centromeric binding and reproductive isolation in Drosophila. PLoS Genet 2021; 17:e1009744. [PMID: 34424906 PMCID: PMC8412352 DOI: 10.1371/journal.pgen.1009744] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/02/2021] [Accepted: 07/27/2021] [Indexed: 12/26/2022] Open
Abstract
Postzygotic isolation by genomic conflict is a major cause for the formation of species. Despite its importance, the molecular mechanisms that result in the lethality of interspecies hybrids are still largely unclear. The genus Drosophila, which contains over 1600 different species, is one of the best characterized model systems to study these questions. We showed in the past that the expression levels of the two hybrid incompatibility factors Hmr and Lhr diverged in the two closely related Drosophila species, D. melanogaster and D. simulans, resulting in an increased level of both proteins in interspecies hybrids. The overexpression of the two proteins also leads to mitotic defects, a misregulation in the expression of transposable elements and decreased fertility in pure species. In this work, we describe a distinct six subunit protein complex containing HMR and LHR and analyse the effect of Hmr mutations on complex integrity and function. Our experiments suggest that HMR needs to bring together components of centromeric and pericentromeric chromatin to fulfil its physiological function and to cause hybrid male lethality. A major cause of biological speciation is the sterility and/or lethality of hybrids. This hybrid lethality is thought to be the consequence of two incompatible genomes of the two different species. We used the fruit fly Drosophila melanogaster as a model system to isolate a defined protein complex, which mediates this hybrid lethality. Our data suggest that this complex containing six subunits has evolved in one Drosophila species (Drosophila melanogaster) to bring together components of centromeric and pericentromeric chromatin. We show that the integrity of the complex is necessary for its genomic binding patterns and its ability to maintain fertility in female Drosophila melanogaster flies. Hybrid males between Drosophila melanogaster and the very closely related species Drosophila simulans die because they contain elevated levels of this complex. These high levels result in mitotic defects and a misregulation in the expression of transposable elements in those hybrids. Our results show that mutations that interfere with the complex’s function in Drosophila melanogaster also fail to induce lethality in hybrids suggesting that its evolutionary acquired functions in one species induce lethality in interspecies hybrids.
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Affiliation(s)
- Andrea Lukacs
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Andreas W. Thomae
- Biomedical Center, Core Facility Bioimaging, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Peter Krueger
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Tamas Schauer
- Biomedical Center, Bioinformatics Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Anuroop V. Venkatasubramani
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Natalia Y. Kochanova
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Wasim Aftab
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Rupam Choudhury
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Ignasi Forne
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
- * E-mail:
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5
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Lauria Sneideman MP, Meller VH. Drosophila Satellite Repeats at the Intersection of Chromatin, Gene Regulation and Evolution. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 60:1-26. [PMID: 34386870 DOI: 10.1007/978-3-030-74889-0_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Satellite repeats make up a large fraction of the genomes of many higher eukaryotes. Until recently these sequences were viewed as molecular parasites with few functions. Drosophila melanogaster and related species have a wealth of diverse satellite repeats. Comparative studies of Drosophilids have been instrumental in understanding how these rapidly evolving sequences change and move. Remarkably, satellite repeats have been found to modulate gene expression and mediate genetic conflicts between chromosomes and between closely related fly species. This suggests that satellites play a key role in speciation. We have taken advantage of the depth of research on satellite repeats in flies to review the known functions of these sequences and consider their central role in evolution and gene expression.
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Affiliation(s)
| | - Victoria H Meller
- Department of Biological Sciences, Wayne State University, Detroit, MI, USA.
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6
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Martins NMC, Cisneros-Soberanis F, Pesenti E, Kochanova NY, Shang WH, Hori T, Nagase T, Kimura H, Larionov V, Masumoto H, Fukagawa T, Earnshaw WC. H3K9me3 maintenance on a human artificial chromosome is required for segregation but not centromere epigenetic memory. J Cell Sci 2020; 133:jcs242610. [PMID: 32576667 PMCID: PMC7390644 DOI: 10.1242/jcs.242610] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/11/2020] [Indexed: 12/24/2022] Open
Abstract
Most eukaryotic centromeres are located within heterochromatic regions. Paradoxically, heterochromatin can also antagonize de novo centromere formation, and some centromeres lack it altogether. In order to investigate the importance of heterochromatin at centromeres, we used epigenetic engineering of a synthetic alphoidtetO human artificial chromosome (HAC), to which chimeric proteins can be targeted. By tethering the JMJD2D demethylase (also known as KDM4D), we removed heterochromatin mark H3K9me3 (histone 3 lysine 9 trimethylation) specifically from the HAC centromere. This caused no short-term defects, but long-term tethering reduced HAC centromere protein levels and triggered HAC mis-segregation. However, centromeric CENP-A was maintained at a reduced level. Furthermore, HAC centromere function was compatible with an alternative low-H3K9me3, high-H3K27me3 chromatin signature, as long as residual levels of H3K9me3 remained. When JMJD2D was released from the HAC, H3K9me3 levels recovered over several days back to initial levels along with CENP-A and CENP-C centromere levels, and mitotic segregation fidelity. Our results suggest that a minimal level of heterochromatin is required to stabilize mitotic centromere function but not for maintaining centromere epigenetic memory, and that a homeostatic pathway maintains heterochromatin at centromeres.This article has an associated First Person interview with the first authors of the paper.
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Affiliation(s)
| | | | - Elisa Pesenti
- Wellcome Trust Centre for Cell Biology, Edinburgh, UK
| | | | - Wei-Hao Shang
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Tetsuya Hori
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | | | - Hiroshi Kimura
- Cell Biology Unit, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Vladimir Larionov
- National Cancer Institute, National Institutes of Health, Bethesda, USA
| | | | - Tatsuo Fukagawa
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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7
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Kochanova NY, Schauer T, Mathias GP, Lukacs A, Schmidt A, Flatley A, Schepers A, Thomae AW, Imhof A. A multi-layered structure of the interphase chromocenter revealed by proximity-based biotinylation. Nucleic Acids Res 2020; 48:4161-4178. [PMID: 32182352 PMCID: PMC7192626 DOI: 10.1093/nar/gkaa145] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/18/2020] [Accepted: 02/25/2020] [Indexed: 12/26/2022] Open
Abstract
During interphase centromeres often coalesce into a small number of chromocenters, which can be visualized as distinct, DAPI dense nuclear domains. Intact chromocenters play a major role in maintaining genome stability as they stabilize the transcriptionally silent state of repetitive DNA while ensuring centromere function. Despite its biological importance, relatively little is known about the molecular composition of the chromocenter or the processes that mediate chromocenter formation and maintenance. To provide a deeper molecular insight into the composition of the chromocenter and to demonstrate the usefulness of proximity-based biotinylation as a tool to investigate those questions, we performed super resolution microscopy and proximity-based biotinylation experiments of three distinct proteins associated with the chromocenter in Drosophila. Our work revealed an intricate internal architecture of the chromocenter suggesting a complex multilayered structure of this intranuclear domain.
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Affiliation(s)
- Natalia Y Kochanova
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Tamas Schauer
- Biomedical Center, Bioinformatics Core Facility, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Grusha Primal Mathias
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andrea Lukacs
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andreas Schmidt
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Andrew Flatley
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility and Research Group Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Aloys Schepers
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility and Research Group Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Andreas W Thomae
- Biomedical Center, Core Facility Bioimaging, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
| | - Axel Imhof
- Biomedical Center, Chromatin Proteomics Group, Department of Molecular Biology, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
- Biomedical Center, Protein Analysis Unit, Faculty of Medicine, Ludwig-Maximilians-Universität München, Großhaderner Strasse 9, 82152 Planegg-Martinsried, Germany
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8
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Sharma A, Kinney NA, Timoshevskiy VA, Sharakhova MV, Sharakhov IV. Structural Variation of the X Chromosome Heterochromatin in the Anopheles gambiae Complex. Genes (Basel) 2020; 11:E327. [PMID: 32204543 PMCID: PMC7140835 DOI: 10.3390/genes11030327] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/31/2022] Open
Abstract
Heterochromatin is identified as a potential factor driving diversification of species. To understand the magnitude of heterochromatin variation within the Anopheles gambiae complex of malaria mosquitoes, we analyzed metaphase chromosomes in An. arabiensis, An. coluzzii, An. gambiae, An. merus, and An. quadriannulatus. Using fluorescence in situ hybridization (FISH) with ribosomal DNA (rDNA), a highly repetitive fraction of DNA, and heterochromatic Bacterial Artificial Chromosome (BAC) clones, we established the correspondence of pericentric heterochromatin between the metaphase and polytene X chromosomes of An. gambiae. We then developed chromosome idiograms and demonstrated that the X chromosomes exhibit qualitative differences in their pattern of heterochromatic bands and position of satellite DNA (satDNA) repeats among the sibling species with postzygotic isolation, An. arabiensis, An. merus, An. quadriannulatus, and An. coluzzii or An. gambiae. The identified differences in the size and structure of the X chromosome heterochromatin point to a possible role of repetitive DNA in speciation of mosquitoes. We found that An. coluzzii and An. gambiae, incipient species with prezygotic isolation, share variations in the relative positions of the satDNA repeats and the proximal heterochromatin band on the X chromosomes. This previously unknown genetic polymorphism in malaria mosquitoes may be caused by a differential amplification of DNA repeats or an inversion in the sex chromosome heterochromatin.
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Affiliation(s)
- Atashi Sharma
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
| | - Nicholas A. Kinney
- Genomics Bioinformatics and Computational Biology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA;
| | - Vladimir A. Timoshevskiy
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
| | - Maria V. Sharakhova
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
- Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Laboratory of Ecology, Genetics and Environmental Protection, Tomsk State University, 634050 Tomsk, Russia
| | - Igor V. Sharakhov
- Department of Entomology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA; (A.S.); (V.A.T.); (M.V.S.)
- Genomics Bioinformatics and Computational Biology, Virginia Polytechnic and State University, Blacksburg, VA 24061, USA;
- Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Cytology and Genetics, Tomsk State University, 634050 Tomsk, Russia
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9
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Regulation of Nucleolar Dominance in Drosophila melanogaster. Genetics 2020; 214:991-1004. [PMID: 32122935 PMCID: PMC7153946 DOI: 10.1534/genetics.119.302471] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 02/26/2020] [Indexed: 12/18/2022] Open
Abstract
In eukaryotic genomes, ribosomal RNA (rRNA) genes exist as tandemly repeated clusters, forming ribosomal DNA (rDNA) loci. Each rDNA locus typically contains hundreds of rRNA genes to meet the high demand of ribosome biogenesis. Nucleolar dominance is a phenomenon whereby individual rDNA loci are entirely silenced or transcribed, and is believed to be a mechanism to control rRNA dosage. Nucleolar dominance was originally noted to occur in interspecies hybrids, and has been shown to occur within a species (i.e., nonhybrid context). However, studying nucleolar dominance within a species has been challenging due to the highly homogenous sequence across rDNA loci. By utilizing single nucleotide polymorphisms between X rDNA and Y rDNA loci in males, as well as sequence variations between two X rDNA loci in females, we conducted a thorough characterization of nucleolar dominance throughout development of Drosophila melanogaster. We demonstrate that nucleolar dominance is a developmentally regulated program that occurs in nonhybrid, wild-type D. melanogaster, where Y rDNA dominance is established during male embryogenesis, whereas females normally do not exhibit dominance between two X rDNA loci. By utilizing various chromosomal complements (e.g., X/Y, X/X, X/X/Y) and a chromosome rearrangement, we show that the short arm of the Y chromosome including the Y rDNA likely contains information that instructs the state of nucleolar dominance. Our study begins to reveal the mechanisms underlying the selection of rDNA loci for activation/silencing in nucleolar dominance in the context of nonhybrid D. melanogaster.
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10
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Cooper JC, Lukacs A, Reich S, Schauer T, Imhof A, Phadnis N. Altered Localization of Hybrid Incompatibility Proteins in Drosophila. Mol Biol Evol 2020; 36:1783-1792. [PMID: 31038678 PMCID: PMC6657725 DOI: 10.1093/molbev/msz105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding the molecular basis of hybrid incompatibilities is a fundamental pursuit in evolutionary genetics. In crosses between Drosophila melanogaster females and Drosophila simulans males, an interaction between at least three genes is necessary for hybrid male lethality: Hmr mel, Lhr sim, and gfzf sim. Although HMR and LHR physically bind each other and function together in a single complex, the connection between gfzf and either of these proteins remains mysterious. Here, we show that GFZF localizes to many regions of the genome in both D. melanogaster and D. simulans, including at telomeric retrotransposon repeats. We find that GFZF localization at telomeres is significantly different between these two species, reflecting the rapid evolution of telomeric retrotransposon copy number composition between the two species. Next, we show that GFZF and HMR normally do not colocalize in D. melanogaster. In interspecies hybrids, however, HMR shows extensive mis-localization to GFZF sites, thus uncovering a new molecular interaction between these hybrid incompatibility factors. We find that spreading of HMR to GFZF sites requires gfzf sim but not Lhr sim, suggesting distinct roles for these factors in the hybrid incompatibility. Finally, we find that overexpression of HMR and LHR within species is sufficient to mis-localize HMR to GFZF binding sites, indicating that HMR has a natural low affinity for GFZF sites. Together, these studies provide the first insights into the different properties of gfzf between D. melanogaster and D. simulans, and uncover a molecular interaction between gfzf and Hmr in the form of altered protein localization.
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Affiliation(s)
| | - Andrea Lukacs
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany
| | - Shelley Reich
- School of Biological Sciences, University of Utah, Salt Lake City, UT
| | - Tamas Schauer
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany
| | - Axel Imhof
- Faculty of Medicine, Institute for Molecular Biology, Biomedical Center (BMC), LMU Munich, Germany.,Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität Müchen, Munich, Germany
| | - Nitin Phadnis
- School of Biological Sciences, University of Utah, Salt Lake City, UT
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11
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Chu Z, Guo W, Hu W, Mei J. Delayed elimination of paternal mtDNA in the interspecific hybrid of Pelteobagrus fulvidraco and Pelteobagrus vachelli during early embryogenesis. Gene 2019; 704:1-7. [PMID: 30970275 DOI: 10.1016/j.gene.2019.04.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/14/2019] [Accepted: 04/05/2019] [Indexed: 11/29/2022]
Abstract
Mitochondrial homoplasmy is essential for normal development, as its heteroplasmy usually leads to abnormal or diseased phenotypes in mammals. So far, diverse mechanisms have been proposed to play roles in ensuring uniparental inheritance of mitochondria in many organisms. In recent years, hybrid yellow catfish from mating female yellow catfish (Pelteobagrus fulvidraco) with male darkbarbel catfish (Pelteobagrus vachelli) has been widely cultured in China due to its fast-growing. However, a high rate of abnormal and defective embryos was observed in the offsprings of hybrid yellow catfish. In this study, we systematically investigated the elimination process of paternal mitochondrial DNA (mtDNA) in yellow catfish and hybrid yellow catfish. The mtDNA contents significantly decreased in the isolated mature sperm compared with the semen. Different from the elimination of paternal mtDNA after fertilization in yellow catfish, paternal mtDNA was retained in the developmental embryos of hybrid yellow catfish as later as gastrula stage, indicating a delay of elimination for paternal mtDNA and mitochondrial heteroplasmy during embryogenesis in hybrid yellow catfish. Altogether, the present study suggests that mitochondrial heteroplasmy may affect embryonic development of hybrid progeny between catfish species.
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Affiliation(s)
- Zhenzhen Chu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenjie Guo
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Weihua Hu
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Jie Mei
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
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12
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Yoshida K, Ishikawa A, Toyoda A, Shigenobu S, Fujiyama A, Kitano J. Functional divergence of a heterochromatin‐binding protein during stickleback speciation. Mol Ecol 2018; 28:1563-1578. [DOI: 10.1111/mec.14841] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/03/2018] [Accepted: 08/10/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Kohta Yoshida
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
| | - Asano Ishikawa
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory National Institute of Genetics Mishima Shizuoka Japan
| | - Shuji Shigenobu
- NIBB Core Research Facilities National Institute for Basic Biology Okazaki Aichi Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory National Institute of Genetics Mishima Shizuoka Japan
| | - Jun Kitano
- Division of Ecological Genetics National Institute of Genetics Mishima Shizuoka Japan
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13
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Graziadio L, Palumbo V, Cipressa F, Williams BC, Cenci G, Gatti M, Goldberg ML, Bonaccorsi S. Phenotypic characterization of diamond (dind), a Drosophila gene required for multiple aspects of cell division. Chromosoma 2018; 127:489-504. [PMID: 30120539 DOI: 10.1007/s00412-018-0680-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/04/2023]
Abstract
Many genes are required for the assembly of the mitotic apparatus and for proper chromosome behavior during mitosis and meiosis. A fruitful approach to elucidate the mechanisms underlying cell division is the accurate phenotypic characterization of mutations in these genes. Here, we report the identification and characterization of diamond (dind), an essential Drosophila gene required both for mitosis of larval brain cells and for male meiosis. Larvae homozygous for any of the five EMS-induced mutations die in the third-instar stage and exhibit multiple mitotic defects. Mutant brain cells exhibit poorly condensed chromosomes and frequent chromosome breaks and rearrangements; they also show centriole fragmentation, disorganized mitotic spindles, defective chromosome segregation, endoreduplicated metaphases, and hyperploid and polyploid cells. Comparable phenotypes occur in mutant spermatogonia and spermatocytes. The dind gene encodes a non-conserved protein with no known functional motifs. Although the Dind protein exhibits a rather diffuse localization in both interphase and mitotic cells, fractionation experiments indicate that some Dind is tightly associated with the chromatin. Collectively, these results suggest that loss of Dind affects chromatin organization leading to defects in chromosome condensation and integrity, which in turn affect centriole stability and spindle assembly. However, our results do not exclude the possibility that Dind directly affects some behaviors of the spindle and centrosomes.
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Affiliation(s)
- Lucia Graziadio
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy
| | - Valeria Palumbo
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy
| | - Francesca Cipressa
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Museo storico della fisica e centro di studi e ricerche Enrico Fermi, Rome, Italy
| | - Byron C Williams
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
| | - Giovanni Cenci
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Istituto Pasteur Fondazione Cenci Bolognetti, Rome, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.,Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Rome, Italy
| | - Michael L Goldberg
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA.
| | - Silvia Bonaccorsi
- Dipartimento di Biologia e Biotecnologie "C. Darwin", Sapienza, Università di Roma, Rome, Italy.
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14
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Genetic Analyses of Elys Mutations in Drosophila Show Maternal-Effect Lethality and Interactions with Nucleoporin Genes. G3-GENES GENOMES GENETICS 2018; 8:2421-2431. [PMID: 29773558 PMCID: PMC6027884 DOI: 10.1534/g3.118.200361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
ELYS determines the subcellular localizations of Nucleoporins (Nups) during interphase and mitosis. We made loss-of-function mutations of Elys in Drosophila melanogaster and found that ELYS is dispensable for zygotic viability and male fertility but the maternal supply is necessary for embryonic development. Subsequent to fertilization, mitotic progression of the embryos produced by the mutant females is severely disrupted at the first cleavage division, accompanied by irregular behavior of mitotic centrosomes. The Nup160 introgression from D. simulans shows close resemblance to that of the Elys mutations, suggesting a common role for those proteins in the first cleavage division. Our genetic experiments indicated critical interactions between ELYS and three Nup107-160 subcomplex components; hemizygotes of either Nup37, Nup96 or Nup160 were lethal in the genetic background of the Elys mutation. Not only Nup96 and Nup160 but also Nup37 of D. simulans behave as recessive hybrid incompatibility genes with D. melanogaster An evolutionary analysis indicated positive natural selection in the ELYS-like domain of ELYS. Here we propose that genetic incompatibility between Elys and Nups may lead to reproductive isolation between D. melanogaster and D. simulans, although direct evidence is necessary.
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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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