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Robinson KA, Dunn M, Hussey SP, Fritz-Laylin LK. Identification of antibiotics for use in selection of the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. PLoS One 2020; 15:e0240480. [PMID: 33079945 PMCID: PMC7575076 DOI: 10.1371/journal.pone.0240480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/25/2020] [Indexed: 11/21/2022] Open
Abstract
Global amphibian populations are being decimated by chytridiomycosis, a deadly skin infection caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). Although ongoing efforts are attempting to limit the spread of these infections, targeted treatments are necessary to manage the disease. Currently, no tools for genetic manipulation are available to identify and test specific drug targets in these fungi. To facilitate the development of genetic tools in Bd and Bsal, we have tested five commonly used antibiotics with available resistance genes: Hygromycin, Blasticidin, Puromycin, Zeocin, and Neomycin. We have identified effective concentrations of each for selection in both liquid culture and on solid media. These concentrations are within the range of concentrations used for selecting genetically modified cells from a variety of other eukaryotic species.
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Affiliation(s)
- Kristyn A. Robinson
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, United States of America
| | - Mallory Dunn
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, United States of America
| | - Shane P. Hussey
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, United States of America
| | - Lillian K. Fritz-Laylin
- Department of Biology, The University of Massachusetts Amherst, Amherst, MA, United States of America
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Muhtadi R, Lorenz A, Mpaulo SJ, Siebenwirth C, Scherthan H. Catalase T-Deficient Fission Yeast Meiocytes Show Resistance to Ionizing Radiation. Antioxidants (Basel) 2020; 9:antiox9090881. [PMID: 32957622 PMCID: PMC7555645 DOI: 10.3390/antiox9090881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/11/2020] [Accepted: 09/14/2020] [Indexed: 12/20/2022] Open
Abstract
Environmental stress, reactive oxygen species (ROS), or ionizing radiation (IR) can induce adverse effects in organisms and their cells, including mutations and premature aging. DNA damage and its faulty repair can lead to cell death or promote cancer through the accumulation of mutations. Misrepair in germ cells is particularly dangerous as it may lead to alterations in developmental programs and genetic disease in the offspring. DNA damage pathways and radical defense mechanisms mediate resistance to genotoxic stresses. Here, we investigated, in the fission yeast Schizosaccharomyces pombe, the role of the H2O2-detoxifying enzyme cytosolic catalase T (Ctt1) and the Fe2+/Mn2+ symporter Pcl1 in protecting meiotic chromosome dynamics and gamete formation from radicals generated by ROS and IR. We found that wild-type and pcl1-deficient cells respond similarly to X ray doses of up to 300 Gy, while ctt1∆ meiocytes showed a moderate sensitivity to IR but a hypersensitivity to hydrogen peroxide with cells dying at >0.4 mM H2O2. Meiocytes deficient for pcl1, on the other hand, showed a resistance to hydrogen peroxide similar to that of the wild type, surviving doses >40 mM. In all, it appears that in the absence of the main H2O2-detoxifying pathway S. pombe meiocytes are able to survive significant doses of IR-induced radicals.
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Affiliation(s)
- Razan Muhtadi
- Institut für Radiobiologie der Bundeswehr in Verb. mit der Universität Ulm, Neuherbergstr. 11, D-80937 Munich, Germany; (R.M.); (C.S.)
| | - Alexander Lorenz
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK; (A.L.); (S.J.M.)
| | - Samantha J. Mpaulo
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK; (A.L.); (S.J.M.)
| | - Christian Siebenwirth
- Institut für Radiobiologie der Bundeswehr in Verb. mit der Universität Ulm, Neuherbergstr. 11, D-80937 Munich, Germany; (R.M.); (C.S.)
| | - Harry Scherthan
- Institut für Radiobiologie der Bundeswehr in Verb. mit der Universität Ulm, Neuherbergstr. 11, D-80937 Munich, Germany; (R.M.); (C.S.)
- Correspondence: ; Tel.: +49-89-992692-2272
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Brown SD, Mpaulo SJ, Asogwa MN, Jézéquel M, Whitby MC, Lorenz A. DNA sequence differences are determinants of meiotic recombination outcome. Sci Rep 2019; 9:16446. [PMID: 31712578 PMCID: PMC6848502 DOI: 10.1038/s41598-019-52907-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/25/2019] [Indexed: 11/08/2022] Open
Abstract
Meiotic recombination is essential for producing healthy gametes, and also generates genetic diversity. DNA double-strand break (DSB) formation is the initiating step of meiotic recombination, producing, among other outcomes, crossovers between homologous chromosomes (homologs), which provide physical links to guide accurate chromosome segregation. The parameters influencing DSB position and repair are thus crucial determinants of reproductive success and genetic diversity. Using Schizosaccharomyces pombe, we show that the distance between sequence polymorphisms across homologs has a strong impact on meiotic recombination rate. The closer the sequence polymorphisms are to each other across the homologs the fewer recombination events were observed. In the immediate vicinity of DSBs, sequence polymorphisms affect the frequency of intragenic recombination events (gene conversions). Additionally, and unexpectedly, the crossover rate of flanking markers tens of kilobases away from the sequence polymorphisms was affected by their relative position to each other amongst the progeny having undergone intragenic recombination. A major regulator of this distance-dependent effect is the MutSα-MutLα complex consisting of Msh2, Msh6, Mlh1, and Pms1. Additionally, the DNA helicases Rqh1 and Fml1 shape recombination frequency, although the effects seen here are largely independent of the relative position of the sequence polymorphisms.
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Affiliation(s)
- Simon D Brown
- The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- MRC Institute of Genetics & Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Samantha J Mpaulo
- The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Mimi N Asogwa
- The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Marie Jézéquel
- The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Matthew C Whitby
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Alexander Lorenz
- The Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
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Li D, Roca M, Yuecel R, Lorenz A. Immediate visualization of recombination events and chromosome segregation defects in fission yeast meiosis. Chromosoma 2019; 128:385-396. [PMID: 30739171 PMCID: PMC6823302 DOI: 10.1007/s00412-019-00691-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 02/07/2023]
Abstract
Schizosaccharomyces pombe, also known as fission yeast, is an established model for studying chromosome biological processes. Over the years, research employing fission yeast has made important contributions to our knowledge about chromosome segregation during meiosis, as well as meiotic recombination and its regulation. Quantification of meiotic recombination frequency is not a straightforward undertaking, either requiring viable progeny for a genetic plating assay, or relying on laborious Southern blot analysis of recombination intermediates. Neither of these methods lends itself to high-throughput screens to identify novel meiotic factors. Here, we establish visual assays novel to Sz. pombe for characterizing chromosome segregation and meiotic recombination phenotypes. Genes expressing red, yellow, and/or cyan fluorophores from spore-autonomous promoters have been integrated into the fission yeast genomes, either close to the centromere of chromosome 1 to monitor chromosome segregation, or on the arm of chromosome 3 to form a genetic interval at which recombination frequency can be determined. The visual recombination assay allows straightforward and immediate assessment of the genetic outcome of a single meiosis by epi-fluorescence microscopy without requiring tetrad dissection. We also demonstrate that the recombination frequency analysis can be automatized by utilizing imaging flow cytometry to enable high-throughput screens. These assays have several advantages over traditional methods for analyzing meiotic phenotypes.
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Affiliation(s)
- Dmitriy Li
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Iain Fraser Cytometry Centre (IFCC), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Marianne Roca
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Sorbonne Université, 06230, Villefranche-sur-Mer, France
| | - Raif Yuecel
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Iain Fraser Cytometry Centre (IFCC), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alexander Lorenz
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
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Genetic interactions between the chromosome axis-associated protein Hop1 and homologous recombination determinants in Schizosaccharomyces pombe. Curr Genet 2018; 64:1089-1104. [PMID: 29550859 PMCID: PMC6153652 DOI: 10.1007/s00294-018-0827-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 03/14/2018] [Indexed: 11/28/2022]
Abstract
Hop1 is a component of the meiosis-specific chromosome axis and belongs to the evolutionarily conserved family of HORMA domain proteins. Hop1 and its orthologs in higher eukaryotes are a major factor in promoting double-strand DNA break formation and inter-homolog recombination. In budding yeast and mammals, they are also involved in a meiotic checkpoint kinase cascade monitoring the completion of double-strand DNA break repair. We used the fission yeast, Schizosaccharomyces pombe, which lacks a canonical synaptonemal complex to test whether Hop1 has a role beyond supporting the generation of double-strand DNA breaks and facilitating inter-homolog recombination events. We determined how mutants of homologous recombination factors genetically interact with hop1, studied the role(s) of the HORMA domain of Hop1, and characterized a bio-informatically predicted interactor of Hop1, Aho1 (SPAC688.03c). Our observations indicate that in fission yeast, Hop1 does require its HORMA domain to support wild-type levels of meiotic recombination and localization to meiotic chromatin. Furthermore, we show that hop1∆ only weakly interacts genetically with mutants of homologous recombination factors, and in fission yeast likely has no major role beyond break formation and promoting inter-homolog events. We speculate that after the evolutionary loss of the synaptonemal complex, Hop1 likely has become less important for modulating recombination outcome during meiosis in fission yeast, and that this led to a concurrent rewiring of genetic pathways controlling meiotic recombination.
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