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Chaux F, Agier N, Eberhard S, Xu Z. Extraction and selection of high-molecular-weight DNA for long-read sequencing from Chlamydomonas reinhardtii. PLoS One 2024; 19:e0297014. [PMID: 38330024 PMCID: PMC10852265 DOI: 10.1371/journal.pone.0297014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/26/2023] [Indexed: 02/10/2024] Open
Abstract
Recent advances in long-read sequencing technologies have enabled the complete assembly of eukaryotic genomes from telomere to telomere by allowing repeated regions to be fully sequenced and assembled, thus filling the gaps left by previous short-read sequencing methods. Furthermore, long-read sequencing can also help characterizing structural variants, with applications in the fields of genome evolution or cancer genomics. For many organisms, the main bottleneck to sequence long reads remains the lack of robust methods to obtain high-molecular-weight (HMW) DNA. For this purpose, we developed an optimized protocol to extract DNA suitable for long-read sequencing from the unicellular green alga Chlamydomonas reinhardtii, based on CTAB/phenol extraction followed by a size selection step for long DNA molecules. We provide validation results for the extraction protocol, as well as statistics obtained with Oxford Nanopore Technologies sequencing.
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Affiliation(s)
- Frédéric Chaux
- CNRS, UMR7238, Institut de Biologie Paris‐Seine, Laboratory of Computational and Quantitative Biology, Sorbonne Université, Paris, France
| | - Nicolas Agier
- CNRS, UMR7238, Institut de Biologie Paris‐Seine, Laboratory of Computational and Quantitative Biology, Sorbonne Université, Paris, France
| | - Stephan Eberhard
- CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, Sorbonne Université, Paris, France
| | - Zhou Xu
- CNRS, UMR7238, Institut de Biologie Paris‐Seine, Laboratory of Computational and Quantitative Biology, Sorbonne Université, Paris, France
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2
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Chaux F, Agier N, Garrido C, Fischer G, Eberhard S, Xu Z. Telomerase-independent survival leads to a mosaic of complex subtelomere rearrangements in Chlamydomonas reinhardtii. Genome Res 2023; 33:1582-1598. [PMID: 37580131 PMCID: PMC10620057 DOI: 10.1101/gr.278043.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 08/09/2023] [Indexed: 08/16/2023]
Abstract
Telomeres and subtelomeres, the genomic regions located at chromosome extremities, are essential for genome stability in eukaryotes. In the absence of the canonical maintenance mechanism provided by telomerase, telomere shortening induces genome instability. The landscape of the ensuing genome rearrangements is not accessible by short-read sequencing. Here, we leverage Oxford Nanopore Technologies long-read sequencing to survey the extensive repertoire of genome rearrangements in telomerase mutants of the model green microalga Chlamydomonas reinhardtii In telomerase-mutant strains grown for hundreds of generations, most chromosome extremities were capped by short telomere sequences that were either recruited de novo from other loci or maintained in a telomerase-independent manner. Other extremities did not end with telomeres but only with repeated subtelomeric sequences. The subtelomeric elements, including rDNA, were massively rearranged and involved in breakage-fusion-bridge cycles, translocations, recombinations, and chromosome circularization. These events were established progressively over time and displayed heterogeneity at the subpopulation level. New telomere-capped extremities composed of sequences originating from more internal genomic regions were associated with high DNA methylation, suggesting that de novo heterochromatin formation contributes to the restoration of chromosome end stability in C. reinhardtii The diversity of alternative strategies present in the same organism to maintain chromosome integrity and the variety of rearrangements found in telomerase mutants are remarkable, and illustrate genome plasticity at short timescales.
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Affiliation(s)
- Frédéric Chaux
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Nicolas Agier
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Clotilde Garrido
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Gilles Fischer
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France;
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Telomeres and Their Neighbors. Genes (Basel) 2022; 13:genes13091663. [PMID: 36140830 PMCID: PMC9498494 DOI: 10.3390/genes13091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Telomeres are essential structures formed from satellite DNA repeats at the ends of chromosomes in most eukaryotes. Satellite DNA repeat sequences are useful markers for karyotyping, but have a more enigmatic role in the eukaryotic cell. Much work has been done to investigate the structure and arrangement of repetitive DNA elements in classical models with implications for species evolution. Still more is needed until there is a complete picture of the biological function of DNA satellite sequences, particularly when considering non-model organisms. Celebrating Gregor Mendel’s anniversary by going to the roots, this review is designed to inspire and aid new research into telomeres and satellites with a particular focus on non-model organisms and accessible experimental and in silico methods that do not require specialized equipment or expensive materials. We describe how to identify telomere (and satellite) repeats giving many examples of published (and some unpublished) data from these techniques to illustrate the principles behind the experiments. We also present advice on how to perform and analyse such experiments, including details of common pitfalls. Our examples are a selection of recent developments and underexplored areas of research from the past. As a nod to Mendel’s early work, we use many examples from plants and insects, especially as much recent work has expanded beyond the human and yeast models traditional in telomere research. We give a general introduction to the accepted knowledge of telomere and satellite systems and include references to specialized reviews for the interested reader.
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Zamzam G, Lee CW, Milne F, Etsell J, Durnford DG. Live long and prosper: Acetate and its effects on longevity in batch culturing of Chlamydomonas reinhardtii. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Ding H, Zhang N, Cao L, Gong P, Wang X, Li X, Cheng S, Li J, Zhang X. First identification of telomeric DNA sequences in Trichomonas vaginalis. Acta Trop 2022; 225:106196. [PMID: 34687640 DOI: 10.1016/j.actatropica.2021.106196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 10/13/2021] [Accepted: 10/16/2021] [Indexed: 11/28/2022]
Abstract
Trichomoniasis is the most common nonviral sexually transmitted disease; it is caused by Trichomonas vaginalis and seriously threatens human reproductive health. Telomeres are specialised DNA-protein complexes at the ends of chromosomes that have a protective function. The aim of the present study was to identify and characterise the telomeric DNA of T. vaginalis-which has not been previously reported-by multiple molecular methods including sequencing, the Bal nuclease (BAL) 31 nuclease assay, fluorescence in situ hybridisation (FISH), and Southern blotting. We found numerous repeated units of TTTTAGGG in T. vaginalis genomic DNA digested with S1 nuclease in combination with XbaI restriction enzyme. The (TTTTAGGG)n tandem repeats were also highly sensitive to BAL 31 exonuclease digestion. We confirmed that the (TTTTAGGG)n repeats were located at the end of T. vaginalis chromosomes by FISH. Restriction enzyme digestion combined with Southern blotting using a digoxigenin-labelled (TTTTAGGG)5 probe showed that the T. vaginalis telomeric DNA length varied from 1.0 to 1.5 kb. This is the first report on the telomeric DNA sequence of T. vaginalis which includes the length and distribution on chromosomes; our findings lay a foundation for further study on telomere maintenance mechanisms in T. vaginalis.
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Affiliation(s)
- He Ding
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Nan Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Lili Cao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China; Department of Parasite, Jilin Academy of Animal Husbandry and Veterinary Medicine, Changchun 130062, China
| | - Pengtao Gong
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xiaocen Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Xin Li
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Shuqin Cheng
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
| | - Jianhua Li
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China.
| | - Xichen Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China.
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Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021; 49:7571-7587. [PMID: 34165564 PMCID: PMC8287924 DOI: 10.1093/nar/gkab534] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
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Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
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Oliver A, Podell S, Pinowska A, Traller JC, Smith SR, McClure R, Beliaev A, Bohutskyi P, Hill EA, Rabines A, Zheng H, Allen LZ, Kuo A, Grigoriev IV, Allen AE, Hazlebeck D, Allen EE. Diploid genomic architecture of Nitzschia inconspicua, an elite biomass production diatom. Sci Rep 2021; 11:15592. [PMID: 34341414 PMCID: PMC8329260 DOI: 10.1038/s41598-021-95106-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/14/2021] [Indexed: 01/13/2023] Open
Abstract
A near-complete diploid nuclear genome and accompanying circular mitochondrial and chloroplast genomes have been assembled from the elite commercial diatom species Nitzschia inconspicua. The 50 Mbp haploid size of the nuclear genome is nearly double that of model diatom Phaeodactylum tricornutum, but 30% smaller than closer relative Fragilariopsis cylindrus. Diploid assembly, which was facilitated by low levels of allelic heterozygosity (2.7%), included 14 candidate chromosome pairs composed of long, syntenic contigs, covering 93% of the total assembly. Telomeric ends were capped with an unusual 12-mer, G-rich, degenerate repeat sequence. Predicted proteins were highly enriched in strain-specific marker domains associated with cell-surface adhesion, biofilm formation, and raphe system gliding motility. Expanded species-specific families of carbonic anhydrases suggest potential enhancement of carbon concentration efficiency, and duplicated glycolysis and fatty acid synthesis pathways across cytosolic and organellar compartments may enhance peak metabolic output, contributing to competitive success over other organisms in mixed cultures. The N. inconspicua genome delivers a robust new reference for future functional and transcriptomic studies to illuminate the physiology of benthic pennate diatoms and harness their unique adaptations to support commercial algae biomass and bioproduct production.
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Affiliation(s)
- Aaron Oliver
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA
| | - Sheila Podell
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA.
| | | | | | - Sarah R Smith
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - Ryan McClure
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Alex Beliaev
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Pavlo Bohutskyi
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Eric A Hill
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ariel Rabines
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - Hong Zheng
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - Lisa Zeigler Allen
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - Alan Kuo
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, USA
| | - Igor V Grigoriev
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, USA.,Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Andrew E Allen
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | | | - Eric E Allen
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA. .,Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA, USA. .,Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
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Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021. [PMID: 34165564 DOI: 10.1101/2021.01.29.428817)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
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Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
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Hints at the Applicability of Microalgae and Cyanobacteria for the Biodegradation of Plastics. SUSTAINABILITY 2020. [DOI: 10.3390/su122410449] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Massive plastic accumulation has been taking place across diverse landscapes since the 1950s, when large-scale plastic production started. Nowadays, societies struggle with continuously increasing concerns about the subsequent pollution and environmental stresses that have accompanied this plastic revolution. Degradation of used plastics is highly time-consuming and causes volumetric aggregation, mainly due to their high strength and bulky structure. The size of these agglomerations in marine and freshwater basins increases daily. Exposure to weather conditions and environmental microflora (e.g., bacteria and microalgae) can slowly corrode the plastic structure. As has been well documented in recent years, plastic fragments are widespread in marine basins and partially in main global rivers. These are potential sources of negative effects on global food chains. Cyanobacteria (e.g., Synechocystis sp. PCC 6803, and Synechococcus elongatus PCC 7942), which are photosynthetic microorganisms and were previously identified as blue-green algae, are currently under close attention for their abilities to capture solar energy and the greenhouse gas carbon dioxide for the production of high-value products. In the last few decades, these microorganisms have been exploited for different purposes (e.g., biofuels, antioxidants, fertilizers, and ‘superfood’ production). Microalgae (e.g., Chlamydomonas reinhardtii, and Phaeodactylum tricornutum) are also suitable for environmental and biotechnological applications based on the exploitation of solar light. Can photosynthetic bacteria and unicellular eukaryotic algae play a role for further scientific research in the bioremediation of plastics of different sizes present in water surfaces? In recent years, several studies have been targeting the utilization of microorganisms for plastic bioremediation. Among the different phyla, the employment of wild-type or engineered cyanobacteria may represent an interesting, environmentally friendly, and sustainable option.
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