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Darmasaputra GS, van Rijnberk LM, Galli M. Functional consequences of somatic polyploidy in development. Development 2024; 151:dev202392. [PMID: 38415794 PMCID: PMC10946441 DOI: 10.1242/dev.202392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Polyploid cells contain multiple genome copies and arise in many animal tissues as a regulated part of development. However, polyploid cells can also arise due to cell division failure, DNA damage or tissue damage. Although polyploidization is crucial for the integrity and function of many tissues, the cellular and tissue-wide consequences of polyploidy can be very diverse. Nonetheless, many polyploid cell types and tissues share a remarkable similarity in function, providing important information about the possible contribution of polyploidy to cell and tissue function. Here, we review studies on polyploid cells in development, underlining parallel functions between different polyploid cell types, as well as differences between developmentally-programmed and stress-induced polyploidy.
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Affiliation(s)
- Gabriella S. Darmasaputra
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - Lotte M. van Rijnberk
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
| | - Matilde Galli
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, the Netherlands
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2
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Chakraborty A, Peterson NG, King JS, Gross RT, Pla MM, Thennavan A, Zhou KC, DeLuca S, Bursac N, Bowles DE, Wolf MJ, Fox DT. Conserved chamber-specific polyploidy maintains heart function in Drosophila. Development 2023; 150:dev201896. [PMID: 37526609 PMCID: PMC10482010 DOI: 10.1242/dev.201896] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/24/2023] [Indexed: 08/02/2023]
Abstract
Developmentally programmed polyploidy (whole-genome duplication) of cardiomyocytes is common across evolution. Functions of such polyploidy are essentially unknown. Here, in both Drosophila larvae and human organ donors, we reveal distinct polyploidy levels in cardiac organ chambers. In Drosophila, differential growth and cell cycle signal sensitivity leads the heart chamber to reach a higher ploidy/cell size relative to the aorta chamber. Cardiac ploidy-reduced animals exhibit reduced heart chamber size, stroke volume and cardiac output, and acceleration of circulating hemocytes. These Drosophila phenotypes mimic human cardiomyopathies. Our results identify productive and likely conserved roles for polyploidy in cardiac chambers and suggest that precise ploidy levels sculpt many developing tissues. These findings of productive cardiomyocyte polyploidy impact efforts to block developmental polyploidy to improve heart injury recovery.
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Affiliation(s)
- Archan Chakraborty
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC 27710, USA
| | - Nora G. Peterson
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Juliet S. King
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ryan T. Gross
- Department of Surgery, Duke University, Durham, NC 27710, USA
| | | | - Aatish Thennavan
- Department of Systems Biology, UT MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Kevin C. Zhou
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA
| | - Sophia DeLuca
- Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA
| | - Nenad Bursac
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA
| | - Dawn E. Bowles
- Department of Surgery, Duke University, Durham, NC 27710, USA
| | - Matthew J. Wolf
- Department of Medicine, University of Virginia, Charlottesville, VA 22903, USA
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22903, USA
| | - Donald T. Fox
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC 27710, USA
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3
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DeBerardine M, Booth GT, Versluis PP, Lis JT. The NELF pausing checkpoint mediates the functional divergence of Cdk9. Nat Commun 2023; 14:2762. [PMID: 37179384 PMCID: PMC10182999 DOI: 10.1038/s41467-023-38359-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Promoter-proximal pausing by RNA Pol II is a rate-determining step in gene transcription that is hypothesized to be a prominent point at which regulatory factors act. The pausing factor NELF is known to induce and stabilize pausing, but not all kinds of pausing are NELF-mediated. Here, we find that NELF-depleted Drosophila melanogaster cells functionally recapitulate the NELF-independent pausing we previously observed in fission yeast (which lack NELF). Critically, only NELF-mediated pausing establishes a strict requirement for Cdk9 kinase activity for the release of paused Pol II into productive elongation. Upon inhibition of Cdk9, cells with NELF efficiently shutdown gene transcription, while in NELF-depleted cells, defective, non-productive transcription continues unabated. By introducing a strict checkpoint for Cdk9, the evolution of NELF was likely critical to enable increased regulation of Cdk9 in higher eukaryotes, as Cdk9 availability can be restricted to limit gene transcription without inducing wasteful, non-productive transcription.
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Affiliation(s)
- Michael DeBerardine
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Gregory T Booth
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Kanvas Biosciences, Monmouth Junction, NJ, USA
| | - Philip P Versluis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - John T Lis
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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4
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Argandona JA, Kim D, Hansen AK. Comparative transcriptomics of aphid species that diverged > 22 MYA reveals genes that are important for the maintenance of their symbiosis. Sci Rep 2023; 13:5341. [PMID: 37005434 PMCID: PMC10067822 DOI: 10.1038/s41598-023-32291-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 03/25/2023] [Indexed: 04/04/2023] Open
Abstract
Most plant-sap feeding insects have obligate relationships with maternally transmitted bacteria. Aphids require their nutritional endosymbiont, Buchnera aphidicola, for the production of essential amino acids. Such endosymbionts are harbored inside of specialized insect cells called bacteriocytes. Here, we use comparative transcriptomics of bacteriocytes between two recently diverged aphid species, Myzus persicae and Acyrthosiphon pisum, to identify key genes that are important for the maintenance of their nutritional mutualism. The majority of genes with conserved expression profiles in M. persicae and A. pisum are for orthologs previously identified in A. pisum to be important for the symbiosis. However, asparaginase which produces aspartate from asparagine was significantly up-regulated only in A. pisum bacteriocytes, potentially because Buchnera of M. persicae encodes its own asparaginase enzyme unlike Buchnera of A. pisum resulting in Buchnera of A. pisum to be dependent on its aphid host for aspartate. One-to-one orthologs that explained the most amount of variation for bacteriocyte specific mRNA expression for both species includes a collaborative gene for methionine biosynthesis, multiple transporters, a horizontally transmitted gene, and secreted proteins. Finally, we highlight species-specific gene clusters which may contribute to host adaptations and/or accommodations in gene regulation to changes in the symbiont or the symbiosis.
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Affiliation(s)
- Jacob A Argandona
- Department of Entomology, University of California, Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Dohyup Kim
- Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, 900 University Ave, Riverside, CA, 92521, USA.
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5
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Chakraborty A, Peterson NG, King JS, Gross RT, Pla MM, Thennavan A, Zhou KC, DeLuca S, Bursac N, Bowles DE, Wolf MJ, Fox DT. Conserved Chamber-Specific Polyploidy Maintains Heart Function in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.10.528086. [PMID: 36798187 PMCID: PMC9934670 DOI: 10.1101/2023.02.10.528086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Developmentally programmed polyploidy (whole-genome-duplication) of cardiomyocytes is common across evolution. Functions of such polyploidy are essentially unknown. Here, we reveal roles for precise polyploidy levels in cardiac tissue. We highlight a conserved asymmetry in polyploidy level between cardiac chambers in Drosophila larvae and humans. In Drosophila , differential Insulin Receptor (InR) sensitivity leads the heart chamber to reach a higher ploidy/cell size relative to the aorta chamber. Cardiac ploidy-reduced animals exhibit reduced heart chamber size, stroke volume, cardiac output, and acceleration of circulating hemocytes. These Drosophila phenotypes mimic systemic human heart failure. Using human donor hearts, we reveal asymmetry in nuclear volume (ploidy) and insulin signaling between the left ventricle and atrium. Our results identify productive and likely conserved roles for polyploidy in cardiac chambers and suggest precise ploidy levels sculpt many developing tissues. These findings of productive cardiomyocyte polyploidy impact efforts to block developmental polyploidy to improve heart injury recovery.
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6
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Variability of polyteny of giant chromosomes in Drosophila melanogaster salivary glands. Genetica 2023; 151:75-86. [PMID: 36163579 DOI: 10.1007/s10709-022-00168-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 09/13/2022] [Indexed: 02/01/2023]
Abstract
Polyteny is an effective mechanism for accelerating growth and enhancing gene expression in eukaryotes. The purpose of investigation was to study the genetic variability of polyteny degree of giant chromosomes in the salivary glands of Drosophila melanogaster Meig. in relation to the differential fitness of different genotypes. 16 strains, lines and hybrids of fruit flies were studied. This study demonstrates the significant influence of hereditary factors on the level of polytenization of giant chromosomes in Drosophila. This is manifested in the differences between strains and lines, the effect of inbreeding, chromosome isogenization, hybridization, adaptively significant selection, sexual differences, and varying degrees of individual variability of a trait in different strains, lines, and hybrids. The genetic component in the variability of the degree of chromosome polyteny in Drosophila salivary glands was 45.3%, the effect of sex was 9.5%. It has been shown that genetic distances during inbreeding, outbreeding or hybridization, which largely determine the selective value of different genotypes, also affect polyteny patterns. Genetic, humoral, and epigenetic aspects of endocycle regulation, which may underlie the variations in the degree of chromosome polyteny, as well as the biological significance of the phenomenon of endopolyploidy, are discussed.
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7
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Nesterkina M, Bilokon S, Alieksieieva T, Kravchenko I, Hirsch AKH. Genotoxic and mutational potential of monocyclic terpenoids (carvacrol, carvone and thymol) in Drosophila melanogaster. Toxicol Rep 2023; 10:327-333. [PMID: 36911165 PMCID: PMC9996437 DOI: 10.1016/j.toxrep.2023.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/14/2023] [Accepted: 02/21/2023] [Indexed: 02/24/2023] Open
Abstract
Genotoxicity and mutagenicity of monoterpene carvone along with the related monoterpene alcohols - carvacrol and thymol have been studied using Drosophila melanogaster as model system. The viability, pre-imaginal stage duration, level of dominant lethal mutations, unequal crossover in the Bar mutant of D. melanogaster and the influence of monocyclic terpenoids on the multiplication of the nuclear genome in salivary gland cells were investigated. The compounds tested after oral administration (0.02% in 1,2-propylene glycol) influence the degree of chromosome polyteny in salivary gland cells of D. melanogaster larvae. Among the terpenoids examined, carvacrol exhibited the most significant impact on imago lifespan, frequency of dominant lethal mutations, unequal crossover in the Bar mutant when added to the culture medium. Oral administration of terpenoids increases the average level of chromosome polyteny with the highest value for carvacrol - 1178 C compared to control (776 C). The conceivable mechanism of action for monocyclic terpenoids associated with the impact on juvenile hormone activity is debated.
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Affiliation(s)
- Mariia Nesterkina
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, Saarbrücken 66123, Germany.,Department of Genetics and Molecular Biology, Odessa I.I. Mechnikov National University, Odessa 65082, Ukraine
| | - Svitlana Bilokon
- Department of Genetics and Molecular Biology, Odessa I.I. Mechnikov National University, Odessa 65082, Ukraine
| | - Tetiana Alieksieieva
- Department of Genetics and Molecular Biology, Odessa I.I. Mechnikov National University, Odessa 65082, Ukraine
| | - Iryna Kravchenko
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, Saarbrücken 66123, Germany.,Department of Genetics and Molecular Biology, Odessa I.I. Mechnikov National University, Odessa 65082, Ukraine
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Campus Building E 8.1, Saarbrücken 66123, Germany.,Department of Pharmacy, Saarland University, Campus Building E8.1, Saarbrücken 66123, Germany
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8
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Abstract
Determining cellular DNA content is valuable in the study of numerous biological processes, including organ development and injury repair. While FACS analysis of dissociated cells is a widely used method for assaying ploidy in a tissue cell population, for many tissue samples, it is possible and convenient to measure ploidy in situ using light microscopy. Here, we present two protocols for measuring cellular ploidy in tissues. These protocols are based on our studies in Drosophila melanogaster, but these are applicable to other settings as well. We present example results from Drosophila hindgut, midgut, and wing imaginal disc as examples. The first protocol focuses on measuring DNA content from decondensed interphase nuclei, while the second protocol details the visualization of condensed chromosomes for ploidy determination, either from mitotic cells or from interphase cells with drug-induced chromosome condensation. These techniques can be completed in 1 day and require standard lab supplies as well as a fluorescence light microscope.
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Affiliation(s)
- Delisa E Clay
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Benjamin M Stormo
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Donald T Fox
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
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9
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Anderson ME, Smith JL, Grossman AD. Multiple mechanisms for overcoming lethal over-initiation of DNA replication. Mol Microbiol 2022; 118:426-442. [PMID: 36053906 PMCID: PMC9825946 DOI: 10.1111/mmi.14976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/14/2022] [Accepted: 08/25/2022] [Indexed: 01/12/2023]
Abstract
DNA replication is highly regulated and primarily controlled at the step of initiation. In bacteria, the replication initiator DnaA and the origin of replication oriC are the primary targets of regulation. Perturbations that increase or decrease replication initiation can cause a decrease in cell fitness. We found that multiple mechanisms, including an increase in replication elongation and a decrease in replication initiation, can compensate for lethal over-initiation. We found that in Bacillus subtilis, under conditions of rapid growth, loss of yabA, a negative regulator of replication initiation, caused a synthetic lethal phenotype when combined with the dnaA1 mutation that also causes replication over-initiation. We isolated several classes of suppressors that restored viability to dnaA1 ∆yabA double mutants. Some suppressors (relA, nrdR) stimulated replication elongation. Others (dnaC, cshA) caused a decrease in replication initiation. One class of suppressors decreased replication initiation in the dnaA1 ∆yabA mutant by causing a decrease in the amount of the replicative helicase, DnaC. We found that decreased levels of helicase in otherwise wild-type cells were sufficient to decrease replication initiation during rapid growth, indicating that the replicative helicase is limiting for replication initiation. Our results highlight the multiple mechanisms cells use to regulate DNA replication.
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Affiliation(s)
- Mary E. Anderson
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Janet L. Smith
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Alan D. Grossman
- Department of BiologyMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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10
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Panov AA. Giant Cortical Glial Cells in the Central Nervous System of Insects. BIOL BULL+ 2022. [DOI: 10.1134/s106235902205017x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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DNA Damage Responses during the Cell Cycle: Insights from Model Organisms and Beyond. Genes (Basel) 2021; 12:genes12121882. [PMID: 34946831 PMCID: PMC8701014 DOI: 10.3390/genes12121882] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/25/2022] Open
Abstract
Genome damage is a threat to all organisms. To respond to such damage, DNA damage responses (DDRs) lead to cell cycle arrest, DNA repair, and cell death. Many DDR components are highly conserved, whereas others have adapted to specific organismal needs. Immense progress in this field has been driven by model genetic organism research. This review has two main purposes. First, we provide a survey of model organism-based efforts to study DDRs. Second, we highlight how model organism study has contributed to understanding how specific DDRs are influenced by cell cycle stage. We also look forward, with a discussion of how future study can be expanded beyond typical model genetic organisms to further illuminate how the genome is protected.
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Almeida Machado Costa C, Wang XF, Ellsworth C, Deng WM. Polyploidy in development and tumor models in Drosophila. Semin Cancer Biol 2021; 81:106-118. [PMID: 34562587 DOI: 10.1016/j.semcancer.2021.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 09/03/2021] [Accepted: 09/18/2021] [Indexed: 12/26/2022]
Abstract
Polyploidy, a cell status defined as more than two sets of genomic DNA, is a conserved strategy across species that can increase cell size and biosynthetic production, but the functional aspects of polyploidy are nuanced and vary across cell types. Throughout Drosophila developmental stages (embryo, larva, pupa and adult), polyploid cells are present in numerous organs and help orchestrate development while contributing to normal growth, well-being and homeostasis of the organism. Conversely, increasing evidence has shown that polyploid cells are prevalent in Drosophila tumors and play important roles in tumor growth and invasiveness. Here, we summarize the genes and pathways involved in polyploidy during normal and tumorigenic development, the mechanisms underlying polyploidization, and the functional aspects of polyploidy in development, homeostasis and tumorigenesis in the Drosophila model.
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Affiliation(s)
- Caique Almeida Machado Costa
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Calder Ellsworth
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA 70112, United States.
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Maya-Maldonado K, Cime-Castillo J, Maya-Lucas O, Argotte-Ramos R, Rodríguez MC, Lanz-Mendoza H. Transcriptome analysis uncover differential regulation in cell cycle, immunity, and metabolism in Anopheles albimanus during immune priming with Plasmodium berghei. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 120:104046. [PMID: 33600838 DOI: 10.1016/j.dci.2021.104046] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
In invertebrates, "immunological priming" is considered as the ability to acquire a protective (adaptive) immune response against a pathogen due to previous exposure to the same organism. To date, the mechanism by which this type of adaptive immune response originates in insects is not well understood. In the Anopheles albimanus - Plasmodium berghei model, a DNA synthesis that probably indicates an endoreplication process during priming induction has been evidenced. This work aimed to know the transcriptomic profile in the midguts of An. albimanus after priming induction. Our analysis indicates the participation of regulatory elements of the cell cycle in the immunological priming and points out the importance of the cell cycle regulation in the mosquito midgut.
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Affiliation(s)
- Krystal Maya-Maldonado
- Centro de Investigaciones sobre Enfermedades Infecciosas. Instituto Nacional de Salud Pública, Av. Universidad 655, CP. 62100, Cuernavaca, Morelos, Mexico
| | - Jorge Cime-Castillo
- Centro de Investigaciones sobre Enfermedades Infecciosas. Instituto Nacional de Salud Pública, Av. Universidad 655, CP. 62100, Cuernavaca, Morelos, Mexico
| | - Otoniel Maya-Lucas
- Novo Nordisk Foundation Center for Basic Metabolic Research. University of Copenhagen, Blegdamsvej 3B, DK-2200, Copenhagen, Denmark
| | - Rocio Argotte-Ramos
- Centro de Investigaciones sobre Enfermedades Infecciosas. Instituto Nacional de Salud Pública, Av. Universidad 655, CP. 62100, Cuernavaca, Morelos, Mexico
| | - Maria Carmen Rodríguez
- Centro de Investigaciones sobre Enfermedades Infecciosas. Instituto Nacional de Salud Pública, Av. Universidad 655, CP. 62100, Cuernavaca, Morelos, Mexico
| | - Humberto Lanz-Mendoza
- Centro de Investigaciones sobre Enfermedades Infecciosas. Instituto Nacional de Salud Pública, Av. Universidad 655, CP. 62100, Cuernavaca, Morelos, Mexico.
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14
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Wang XF, Yang SA, Gong S, Chang CH, Portilla JM, Chatterjee D, Irianto J, Bao H, Huang YC, Deng WM. Polyploid mitosis and depolyploidization promote chromosomal instability and tumor progression in a Notch-induced tumor model. Dev Cell 2021; 56:1976-1988.e4. [PMID: 34146466 DOI: 10.1016/j.devcel.2021.05.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/18/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023]
Abstract
Ploidy variation is a cancer hallmark and is frequently associated with poor prognosis in high-grade cancers. Using a Drosophila solid-tumor model where oncogenic Notch drives tumorigenesis in a transition-zone microenvironment in the salivary gland imaginal ring, we find that the tumor-initiating cells normally undergo endoreplication to become polyploid. Upregulation of Notch signaling, however, induces these polyploid transition-zone cells to re-enter mitosis and undergo tumorigenesis. Growth and progression of the transition-zone tumor are fueled by a combination of polyploid mitosis, endoreplication, and depolyploidization. Both polyploid mitosis and depolyploidization are error prone, resulting in chromosomal copy-number variation and polyaneuploidy. Comparative RNA-seq and epistasis analysis reveal that the DNA-damage response genes, also active during meiosis, are upregulated in these tumors and are required for the ploidy-reduction division. Together, these findings suggest that polyploidy and associated cell-cycle variants are critical for increased tumor-cell heterogeneity and genome instability during cancer progression.
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Affiliation(s)
- Xian-Feng Wang
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Sheng-An Yang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Shangyu Gong
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Chih-Hsuan Chang
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Juan Martin Portilla
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Deeptiman Chatterjee
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Jerome Irianto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Hongcun Bao
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Yi-Chun Huang
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA
| | - Wu-Min Deng
- Department of Biochemistry and Molecular Biology, Tulane University Louisiana Center Research Center, New Orleans, LA 70112, USA; Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA.
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15
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Suh A, Dion-Côté AM. New Perspectives on the Evolution of Within-Individual Genome Variation and Germline/Soma Distinction. Genome Biol Evol 2021; 13:evab095. [PMID: 33963843 PMCID: PMC8245192 DOI: 10.1093/gbe/evab095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2021] [Indexed: 12/19/2022] Open
Abstract
Genomes can vary significantly even within the same individual. The underlying mechanisms are manifold, ranging from somatic mutation and recombination, development-associated ploidy changes and genetic bottlenecks, over to programmed DNA elimination during germline/soma differentiation. In this perspective piece, we briefly review recent developments in the study of within-individual genome variation in eukaryotes and prokaryotes. We highlight a Society for Molecular Biology and Evolution 2020 virtual symposium entitled "Within-individual genome variation and germline/soma distinction" and the present Special Section of the same name in Genome Biology and Evolution, together fostering cross-taxon synergies in the field to identify and tackle key open questions in the understanding of within-individual genome variation.
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Affiliation(s)
- Alexander Suh
- School of Biological Sciences—Organisms and the Environment, University of East Anglia, Norwich, United Kingdom
- Department of Organismal Biology—Systematic Biology, Evolutionary Biology Centre (EBC), Science for Life Laboratory, Uppsala University, Sweden
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16
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Amabis JM, Gorab E. Dramatic nucleolar dispersion in the salivary gland of Schwenkfeldina sp. (Diptera: Sciaridae). Sci Rep 2021; 11:8347. [PMID: 33863925 PMCID: PMC8052372 DOI: 10.1038/s41598-021-87012-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/24/2021] [Indexed: 11/16/2022] Open
Abstract
Micronucleoli are among the structures composing the peculiar scenario of the nucleolus in salivary gland nuclei of dipterans representative of Sciaridae. Micronucleolar bodies contain ribosomal DNA and RNA, are transcriptionally active and may appear free in the nucleoplasm or associated with specific chromosome regions in salivary gland nuclei. This report deals with an extreme case of nucleolar fragmentation/dispersion detected in the salivary gland of Schwenkfeldina sp. Such a phenomenon in this species was found to be restricted to cell types undergoing polyteny and seems to be differentially controlled according to the cell type. Furthermore, transcriptional activity was detected in virtually all the micronucleolar bodies generated in the salivary gland. The relative proportion of the rDNA in polytene and diploid tissues showed that rDNA under-replication did not occur in polytene nuclei suggesting that the nucleolar and concomitant rDNA dispersion in Schwenkfeldina sp. may reflect a previously hypothesised process in order to counterbalance the rDNA loss due to the under-replication. The chromosomal distribution of epigenetic markers for the heterochromatin agreed with early cytological observations in this species suggesting that heterochromatin is spread throughout the chromosome length of Schwenkfeldina sp. A comparison made with results from another sciarid species argues for a role played by the heterochromatin in the establishment of the rDNA topology in polytene nuclei of Sciaridae.
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Affiliation(s)
- José Mariano Amabis
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, Cidade Universitária, São Paulo, SP, 05508-090, Brazil
| | - Eduardo Gorab
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, Cidade Universitária, São Paulo, SP, 05508-090, Brazil.
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17
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Communal living: the role of polyploidy and syncytia in tissue biology. Chromosome Res 2021; 29:245-260. [PMID: 34075512 PMCID: PMC8169410 DOI: 10.1007/s10577-021-09664-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/10/2021] [Accepted: 05/16/2021] [Indexed: 01/22/2023]
Abstract
Multicellular organisms are composed of tissues with diverse cell sizes. Whether a tissue primarily consists of numerous, small cells as opposed to fewer, large cells can impact tissue development and function. The addition of nuclear genome copies within a common cytoplasm is a recurring strategy to manipulate cellular size within a tissue. Cells with more than two genomes can exist transiently, such as in developing germlines or embryos, or can be part of mature somatic tissues. Such nuclear collectives span multiple levels of organization, from mononuclear or binuclear polyploid cells to highly multinucleate structures known as syncytia. Here, we review the diversity of polyploid and syncytial tissues found throughout nature. We summarize current literature concerning tissue construction through syncytia and/or polyploidy and speculate why one or both strategies are advantageous.
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18
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Mérel V, Boulesteix M, Fablet M, Vieira C. Transposable elements in Drosophila. Mob DNA 2020; 11:23. [PMID: 32636946 PMCID: PMC7334843 DOI: 10.1186/s13100-020-00213-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/14/2020] [Indexed: 12/25/2022] Open
Abstract
Drosophila has been studied as a biological model for many years and many discoveries in biology rely on this species. Research on transposable elements (TEs) is not an exception. Drosophila has contributed significantly to our knowledge on the mechanisms of transposition and their regulation, but above all, it was one of the first organisms on which genetic and genomic studies of populations were done. In this review article, in a very broad way, we will approach the TEs of Drosophila with a historical hindsight as well as recent discoveries in the field.
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Affiliation(s)
- Vincent Mérel
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Matthieu Boulesteix
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Marie Fablet
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
| | - Cristina Vieira
- Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622 Villeurbanne, France
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19
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Kolesnikova TD, Kolodyazhnaya AV, Pokholkova GV, Schubert V, Dovgan VV, Romanenko SA, Prokopov DY, Zhimulev IF. Effects of Mutations in the Drosophila melanogaster Rif1 Gene on the Replication and Underreplication of Pericentromeric Heterochromatin in Salivary Gland Polytene Chromosomes. Cells 2020; 9:cells9061501. [PMID: 32575592 PMCID: PMC7349278 DOI: 10.3390/cells9061501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 01/09/2023] Open
Abstract
In Drosophila salivary gland polytene chromosomes, a substantial portion of heterochromatin is underreplicated. The combination of mutations SuURES and Su(var)3-906 results in the polytenization of a substantial fraction of unique and moderately repeated sequences but has almost no effect on satellite DNA replication. The Rap1 interacting factor 1 (Rif) protein is a conserved regulator of replication timing, and in Drosophila, it affects underreplication in polytene chromosomes. We compared the morphology of pericentromeric regions and labeling patterns of in situ hybridization of heterochromatin-specific DNA probes between wild-type salivary gland polytene chromosomes and the chromosomes of Rif1 mutants and SuUR Su(var)3-906 double mutants. We show that, despite general similarities, heterochromatin zones exist that are polytenized only in the Rif1 mutants, and that there are zones that are under specific control of Su(var)3-9. In the Rif1 mutants, we found additional polytenization of the largest blocks of satellite DNA (in particular, satellite 1.688 of chromosome X and simple satellites in chromosomes X and 4) as well as partial polytenization of chromosome Y. Data on pulsed incorporation of 5-ethynyl-2′-deoxyuridine (EdU) into polytene chromosomes indicated that in the Rif1 mutants, just as in the wild type, most of the heterochromatin becomes replicated during the late S phase. Nevertheless, a significantly increased number of heterochromatin replicons was noted. These results suggest that Rif1 regulates the activation probability of heterochromatic origins in the satellite DNA region.
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Affiliation(s)
- Tatyana D. Kolesnikova
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
- Laboratory of Structural, Functional and Comparative Genomics, Novosibirsk State University, 630090 Novosibirsk, Russia
- Correspondence:
| | - Alexandra V. Kolodyazhnaya
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Galina V. Pokholkova
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466 Seeland, Germany;
| | - Viktoria V. Dovgan
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Svetlana A. Romanenko
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
| | - Dmitry Yu. Prokopov
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
| | - Igor F. Zhimulev
- Institute of Molecular and Cellular Biology, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.V.K.); (G.V.P.); (V.V.D.); (S.A.R.); (D.Y.P.); (I.F.Z.)
- Laboratory of Structural, Functional and Comparative Genomics, Novosibirsk State University, 630090 Novosibirsk, Russia
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20
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Ren D, Song J, Ni M, Kang L, Guo W. Regulatory Mechanisms of Cell Polyploidy in Insects. Front Cell Dev Biol 2020; 8:361. [PMID: 32548115 PMCID: PMC7272692 DOI: 10.3389/fcell.2020.00361] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 04/22/2020] [Indexed: 12/14/2022] Open
Abstract
Polyploidy cells undergo the endocycle to generate DNA amplification without cell division and have important biological functions in growth, development, reproduction, immune response, nutrient support, and conferring resistance to DNA damage in animals. In this paper, we have specially summarized current research progresses in the regulatory mechanisms of cell polyploidy in insects. First, insect hormones including juvenile hormone and 20-hydroxyecdysone regulate the endocycle of variant cells in diverse insect species. Second, cells skip mitotic division in response to developmental programming and conditional stimuli such as wound healing, regeneration, and aging. Third, the reported regulatory pathways of mitotic to endocycle switch (MES), including Notch, Hippo, and JNK signaling pathways, are summarized and constructed into genetic network. Thus, we think that the studies in crosstalk of hormones and their effects on canonical pathways will shed light on the mechanism of cell polyploidy and elucidate the evolutionary adaptions of MES through diverse insect species.
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Affiliation(s)
- Dani Ren
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Juan Song
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Ming Ni
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, Hebei University, Baoding, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China.,College of Life Sciences, Hebei University, Baoding, China
| | - Wei Guo
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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21
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Jacob D, Brian J. The short and intricate life of the suspensor. PHYSIOLOGIA PLANTARUM 2020; 169:110-121. [PMID: 31808953 DOI: 10.1111/ppl.13057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/04/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
The suspensor is a short-lived tissue critical for proper embryonic development in many higher plants. While the tissue was initially thought to simply suspend the embryo in the endosperm, it has been found through decades of research that it serves multiple important purposes. The suspensor has been found to be vital for proper embryo patterning and numerous studies have been undertaken into the complex transcriptional cross-talk between the suspensor and the embryo proper. Indeed, many suspensor mutants also display abnormalities in the embryo. The suspensor's role as a nutrient conduit has been shown using ultrastructural and histochemical techniques. Biochemical approaches have found that the suspensor is a centre of early embryonic hormone production in several species. The suspensor has also been frequently used as a model for programmed cell death as it shows signs of termination almost immediately upon developing. This review covers the essential functions of the suspensor throughout its short existence from multiple disciplines including structural, genetic and biochemical perspectives.
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Affiliation(s)
- Downs Jacob
- Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
| | - Jones Brian
- Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
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22
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George P, Kinney NA, Liang J, Onufriev AV, Sharakhov IV. Three-dimensional Organization of Polytene Chromosomes in Somatic and Germline Tissues of Malaria Mosquitoes. Cells 2020; 9:cells9020339. [PMID: 32024176 PMCID: PMC7072178 DOI: 10.3390/cells9020339] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/22/2020] [Accepted: 01/28/2020] [Indexed: 12/17/2022] Open
Abstract
Spatial organization of chromosome territories and interactions between interphase chromosomes themselves, as well as with the nuclear periphery, play important roles in epigenetic regulation of the genome function. However, the interplay between inter-chromosomal contacts and chromosome-nuclear envelope attachments in an organism’s development is not well-understood. To address this question, we conducted microscopic analyses of the three-dimensional chromosome organization in malaria mosquitoes. We employed multi-colored oligonucleotide painting probes, spaced 1 Mb apart along the euchromatin, to quantitatively study chromosome territories in larval salivary gland cells and adult ovarian nurse cells of Anopheles gambiae, An. coluzzii, and An. merus. We found that the X chromosome territory has a significantly smaller volume and is more compact than the autosomal arm territories. The number of inter-chromosomal, and the percentage of the chromosome–nuclear envelope, contacts were conserved among the species within the same cell type. However, the percentage of chromosome regions located at the nuclear periphery was typically higher, while the number of inter-chromosomal contacts was lower, in salivary gland cells than in ovarian nurse cells. The inverse correlation was considerably stronger for the autosomes. Consistent with previous theoretical arguments, our data indicate that, at the genome-wide level, there is an inverse relationship between chromosome-nuclear envelope attachments and chromosome–chromosome interactions, which is a key feature of the cell type-specific nuclear architecture.
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Affiliation(s)
- Phillip George
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA; (P.G.); (J.L.)
| | - Nicholas A. Kinney
- Genomics, Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, VA 24061, USA; (N.A.K.); (A.V.O.)
| | - Jiangtao Liang
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA; (P.G.); (J.L.)
| | - Alexey V. Onufriev
- Genomics, Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, VA 24061, USA; (N.A.K.); (A.V.O.)
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061, USA
| | - Igor V. Sharakhov
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061, USA; (P.G.); (J.L.)
- Genomics, Bioinformatics and Computational Biology, Virginia Tech, Blacksburg, VA 24061, USA; (N.A.K.); (A.V.O.)
- Department of Cytology and Genetics, Tomsk State University, 634050 Tomsk, Russian Federation
- Correspondence: ; Tel.: +1-540-231-7316
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23
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Dialynas G, Delabaere L, Chiolo I. Arp2/3 and Unc45 maintain heterochromatin stability in Drosophila polytene chromosomes. Exp Biol Med (Maywood) 2019; 244:1362-1371. [PMID: 31364400 PMCID: PMC6880141 DOI: 10.1177/1535370219862282] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/18/2019] [Indexed: 12/31/2022] Open
Abstract
Repairing DNA double-strand breaks is particularly challenging in pericentromeric heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination. In Drosophila Kc cells, accurate homologous recombination repair of heterochromatic double-strand breaks relies on the relocalization of repair sites to the nuclear periphery before Rad51 recruitment and strand invasion. This movement is driven by Arp2/3-dependent nuclear actin filaments and myosins’ ability to walk along them. Conserved mechanisms enable the relocalization of heterochromatic repair sites in mouse cells, and defects in these pathways lead to massive ectopic recombination in heterochromatin and chromosome rearrangements. In Drosophila polytene chromosomes, extensive DNA movement is blocked by a stiff structure of chromosome bundles. Repair pathways in this context are poorly characterized, and whether heterochromatic double-strand breaks relocalize in these cells is unknown. Here, we show that damage in heterochromatin results in relaxation of the heterochromatic chromocenter, consistent with a dynamic response. Arp2/3, the Arp2/3 activator Scar, and the myosin activator Unc45, are required for heterochromatin stability in polytene cells, suggesting that relocalization enables heterochromatin repair also in this tissue. Together, these studies reveal critical roles for actin polymerization and myosin motors in heterochromatin repair and genome stability across different organisms and tissue types.
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Affiliation(s)
- George Dialynas
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
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24
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Olins DE, Olins AL. Epichromatin and chromomeres: a 'fuzzy' perspective. Open Biol 2019; 8:rsob.180058. [PMID: 29875200 PMCID: PMC6030114 DOI: 10.1098/rsob.180058] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 05/09/2018] [Indexed: 12/17/2022] Open
Abstract
'Epichromatin', the surface of chromatin beneath the interphase nuclear envelope (NE) or at the surface of mitotic chromosomes, was discovered by immunostaining with a specific bivalent mouse monoclonal anti-nucleosome antibody (mAb PL2-6). 'Chromomeres', punctate chromatin particles approximately 200-300 nm in diameter, identified throughout the interphase chromatin and along mitotic chromosomes, were observed by immunostaining with the monovalent papain-derived Fab fragments of bivalent PL2-6. The specific target for PL2-6 appears to include the nucleosome acidic patch. Thus, within the epichromatin and chromomeric regions, this epitope is 'exposed'. Considering that histones possess unstructured 'tails' (i.e. intrinsically disordered peptide regions, IDPR), our perception of these chromatin regions becomes more 'fuzzy' (less defined). We suggest that epichromatin cationic tails facilitate interactions with anionic components of NE membranes. We also suggest that the unstructured histone tails (especially, histone H1 tails), with their presumed promiscuous binding, establish multivalent binding that stabilizes each chromomere as a unit of chromatin higher order structure. We propose an 'unstructured stability' hypothesis, which postulates that the stability of epichromatin and chromomeres (as well as other nuclear chromatin structures) is a consequence of the collective contributions of numerous weak histone IDPR binding interactions arising from the multivalent nucleosome, analogous to antibody avidity.
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Affiliation(s)
- Donald E Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
| | - Ada L Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, 716 Stevens Avenue, Portland, ME 04103, USA
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25
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Stormo BM, Fox DT. Interphase cohesin regulation ensures mitotic fidelity after genome reduplication. Mol Biol Cell 2019; 30:219-227. [PMID: 30462577 PMCID: PMC6589556 DOI: 10.1091/mbc.e17-10-0582] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 10/17/2018] [Accepted: 11/15/2018] [Indexed: 12/24/2022] Open
Abstract
To ensure faithful genome propagation, mitotic cells alternate one round of chromosome duplication with one round of chromosome separation. Chromosome separation failure thus causes genome reduplication, which alters mitotic chromosome structure. Such structural alterations are well documented to impair mitotic fidelity following aberrant genome reduplication, including in diseased states. In contrast, we recently showed that naturally occurring genome reduplication does not alter mitotic chromosome structure in Drosophila papillar cells. Our discovery raised the question of how a cell undergoing genome reduplication might regulate chromosome structure to prevent mitotic errors. Here, we show that papillar cells ensure mitotic fidelity through interphase cohesin regulation. We demonstrate a requirement for cohesins during programmed rounds of papillar genome reduplication known as endocycles. This interphase cohesin regulation relies on cohesin release but not cohesin cleavage and depends on the conserved cohesin regulator Pds5 . Our data suggest that a distinct form of interphase cohesin regulation ensures mitotic fidelity after genome reduplication.
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Affiliation(s)
- Benjamin M. Stormo
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
| | - Donald T. Fox
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710
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26
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Porrati F, Grewe D, Seybert A, Frangakis AS, Eltsov M. FIB-SEM imaging properties of Drosophila melanogaster tissues embedded in Lowicryl HM20. J Microsc 2018; 273:91-104. [PMID: 30417390 DOI: 10.1111/jmi.12764] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 09/17/2018] [Accepted: 10/12/2018] [Indexed: 11/27/2022]
Abstract
Lowicryl resins enable processing of biological material for electron microscopy at the lowest temperatures compatible with resin embedding. When combined with high-pressure freezing and freeze-substitution, Lowicryl embedding supports preservation of fine structural details and fluorescent markers. Here, we analysed the applicability of Lowicryl HM20 embedding for focused ion beam (FIB) scanning electron microscopy (SEM) tomography of Drosophila melanogaster embryonic and larval model systems. We show that the freeze-substitution with per-mill concentrations of uranyl acetate provided sufficient contrast and an image quality of SEM imaging in the range of similar samples analysed by transmission electron microscopy (TEM). Preservation of genetically encoded fluorescent proteins allowed correlative localization of regions of interest (ROI) within the embedded tissue block. TEM on sections cut from the block face enabled evaluation of structural preservation to allow ROI ranking and thus targeted, time-efficient FIB-SEM tomography data collection. The versatility of Lowicryl embedding opens new perspectives for designing hybrid SEM-TEM workflows to comprehensively analyse biological structures. LAY DESCRIPTION: Focused ion beam scanning electron microscopy is becoming a widely used technique for the three-dimensional analysis of biological samples at fine structural details beyond levels feasible for light microscopy. To withstand the abrasion of material by the ion beam and the imaging by the scanning electron beam, biological samples have to be embedded into resins, most commonly these are very dense epoxy-based plastics. However, dense resins generate electron scattering which interferes with the signal from the biological specimen. Furthermore, to improve the imaging contrast, epoxy embedding requires chemical treatments with e.g. heavy metals, which deteriorate the ultrastructure of the biological specimen. In this study we explored the applicability of an electron lucent resin, Lowicryl HM 20, for focused ion beam scanning electron microscopy. The Lowicryl embedding workflow operates at milder chemical treatments and lower temperatures, thus preserving the sub-cellular and sub-organellar organization, as well as fluorescent markers visible by light microscopy. Here we show that focus ion beam scanning electron microscopy of Lowicryl-embedded fruit flies tissues provides reliable imaging revealing fine structural details. Our workflow benefited from use of transmission electron microscopy for the quality control of the ultrastructural preservation and fluorescent light microscopy for localization of regions of interest. The versatility of Lowicryl embedding opens up new perspectives for designing hybrid workflows combining fluorescent light, scanning, and transmission electron microscopy techniques to comprehensively analyze biological structures.
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Affiliation(s)
- F Porrati
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe-University, Frankfurt am Main, Germany
| | - D Grewe
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe-University, Frankfurt am Main, Germany
| | - A Seybert
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe-University, Frankfurt am Main, Germany
| | - A S Frangakis
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe-University, Frankfurt am Main, Germany
| | - M Eltsov
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe-University, Frankfurt am Main, Germany
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27
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Spradling AC. Polytene Chromosome Structure and Somatic Genome Instability. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 82:293-304. [PMID: 29167281 DOI: 10.1101/sqb.2017.82.033670] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Polytene chromosomes have for 80 years provided the highest resolution view of interphase genome structure in an animal cell nucleus. These chromosomes represent the normal genomic state of nearly all Drosophila larval and many adult cells, and a better understanding of their striking banded structure has been sought for decades. A more recently appreciated characteristic of Drosophila polytene cells is somatic genome instability caused by unfinished replication (UR). Repair of stalled forks generates enough deletions in polytene salivary gland cells to alter 10%-90% of the DNA strands within more than 100 UR regions comprising 20% of the euchromatic genome. We accurately map UR regions and show that most approximate large polytene bands, indicating that replication forks frequently stall near band boundaries in late S phase. Chromosome conformation capture has recently identified dense topologically associated domains (TADs) in many genomes and most UR bands are similar or slightly smaller than a cognate Drosophila TAD. We argue that bands serve the evolutionarily ancient function of coordinating genome replication with local gene activity. We also discuss the relatively recent evolution of polyteny and somatic instability in Diptera and propose that these processes helped propel the amazing success of two-winged flies in becoming the most ecologically diverse insect group, with 200 times the number of species as mammals.
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Affiliation(s)
- Allan C Spradling
- Department of Embryology, Howard Hughes Medical Institute, Carnegie Institution for Science, Baltimore, Maryland 21218
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