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Ramming L, Stukenberg D, Sánchez Olmos MDC, Glatter T, Becker A, Schindler D. Rationally designed chromosome fusion does not prevent rapid growth of Vibrio natriegens. Commun Biol 2024; 7:519. [PMID: 38698198 PMCID: PMC11066055 DOI: 10.1038/s42003-024-06234-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 04/23/2024] [Indexed: 05/05/2024] Open
Abstract
DNA replication is essential for the proliferation of all cells. Bacterial chromosomes are replicated bidirectionally from a single origin of replication, with replication proceeding at about 1000 bp per second. For the model organism, Escherichia coli, this translates into a replication time of about 40 min for its 4.6 Mb chromosome. Nevertheless, E. coli can propagate by overlapping replication cycles with a maximum short doubling time of 20 min. The fastest growing bacterium known, Vibrio natriegens, is able to replicate with a generation time of less than 10 min. It has a bipartite genome with chromosome sizes of 3.2 and 1.9 Mb. Is simultaneous replication from two origins a prerequisite for its rapid growth? We fused the two chromosomes of V. natriegens to create a strain carrying one chromosome with a single origin of replication. Compared to the parental, this strain showed no significant deviation in growth rate. This suggests that the split genome is not a prerequisite for rapid growth.
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Affiliation(s)
- Lea Ramming
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Daniel Stukenberg
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | | | - Timo Glatter
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Anke Becker
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany
| | - Daniel Schindler
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-Universität Marburg, Marburg, Germany.
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2
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Lindeboom TA, Sanchez Olmos MDC, Schulz K, Brinkmann CK, Ramírez Rojas AA, Hochrein L, Schindler D. An Optimized Genotyping Workflow for Identifying Highly SCRaMbLEd Synthetic Yeasts. ACS Synth Biol 2024; 13:1116-1127. [PMID: 38597458 PMCID: PMC11036488 DOI: 10.1021/acssynbio.3c00476] [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: 08/03/2023] [Revised: 03/01/2024] [Accepted: 03/25/2024] [Indexed: 04/11/2024]
Abstract
Synthetic Sc2.0 yeast strains contain hundreds to thousands of loxPsym recombination sites that allow restructuring of the Saccharomyces cerevisiae genome by SCRaMbLE. Thus, a highly diverse yeast population can arise from a single genotype. The selection of genetically diverse candidates with rearranged synthetic chromosomes for downstream analysis requires an efficient and straightforward workflow. Here we present loxTags, a set of qPCR primers for genotyping across loxPsym sites to detect not only deletions but also inversions and translocations after SCRaMbLE. To cope with the large number of amplicons, we generated qTagGer, a qPCR genotyping primer prediction tool. Using loxTag-based genotyping and long-read sequencing, we show that light-inducible Cre recombinase L-SCRaMbLE can efficiently generate diverse recombination events when applied to Sc2.0 strains containing a linear or a circular version of synthetic chromosome III.
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Affiliation(s)
- Timon A Lindeboom
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | | | - Karina Schulz
- Department of Molecular Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany
| | - Cedric K Brinkmann
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Adán A Ramírez Rojas
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
| | - Lena Hochrein
- Department of Molecular Biology, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany
| | - Daniel Schindler
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 10, 35043 Marburg, Germany
- Center for Synthetic Microbiology, Philipps-University Marburg, Karl-von-Frisch-Str. 14, 35032Marburg, Germany
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3
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Schindler D, Walker RSK, Jiang S, Brooks AN, Wang Y, Müller CA, Cockram C, Luo Y, García A, Schraivogel D, Mozziconacci J, Pena N, Assari M, Sánchez Olmos MDC, Zhao Y, Ballerini A, Blount BA, Cai J, Ogunlana L, Liu W, Jönsson K, Abramczyk D, Garcia-Ruiz E, Turowski TW, Swidah R, Ellis T, Pan T, Antequera F, Shen Y, Nieduszynski CA, Koszul R, Dai J, Steinmetz LM, Boeke JD, Cai Y. Design, construction, and functional characterization of a tRNA neochromosome in yeast. Cell 2023; 186:5237-5253.e22. [PMID: 37944512 DOI: 10.1016/j.cell.2023.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
Here, we report the design, construction, and characterization of a tRNA neochromosome, a designer chromosome that functions as an additional, de novo counterpart to the native complement of Saccharomyces cerevisiae. Intending to address one of the central design principles of the Sc2.0 project, the ∼190-kb tRNA neochromosome houses all 275 relocated nuclear tRNA genes. To maximize stability, the design incorporates orthogonal genetic elements from non-S. cerevisiae yeast species. Furthermore, the presence of 283 rox recombination sites enables an orthogonal tRNA SCRaMbLE system. Following construction in yeast, we obtained evidence of a potent selective force, manifesting as a spontaneous doubling in cell ploidy. Furthermore, tRNA sequencing, transcriptomics, proteomics, nucleosome mapping, replication profiling, FISH, and Hi-C were undertaken to investigate questions of tRNA neochromosome behavior and function. Its construction demonstrates the remarkable tractability of the yeast model and opens up opportunities to directly test hypotheses surrounding these essential non-coding RNAs.
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Affiliation(s)
- Daniel Schindler
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK; Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany; Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, 35032 Marburg, Germany
| | - Roy S K Walker
- School of Engineering, Institute for Bioengineering, The University of Edinburgh, Edinburgh EH9 3BF, Scotland; School of Natural Sciences and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, NSW 2109, Australia
| | - Shuangying Jiang
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Aaron N Brooks
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Yun Wang
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen 518120, China
| | - Carolin A Müller
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK; School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | - Charlotte Cockram
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Yisha Luo
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Alicia García
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Daniel Schraivogel
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany
| | - Julien Mozziconacci
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Noah Pena
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Mahdi Assari
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | | | - Yu Zhao
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA
| | - Alba Ballerini
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Benjamin A Blount
- Imperial College Centre for Synthetic Biology, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - Jitong Cai
- Department of Biomedical Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lois Ogunlana
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Wei Liu
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Katarina Jönsson
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Dariusz Abramczyk
- School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, Scotland
| | - Eva Garcia-Ruiz
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Tomasz W Turowski
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5a, 02-106 Warszawa, Poland
| | - Reem Swidah
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Tom Ellis
- Imperial College Centre for Synthetic Biology, Imperial College London, London, UK; Department of Bioengineering, Imperial College London, London, UK
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Francisco Antequera
- Instituto de Biología Funcional y Genómica (IBFG), CSIC, Universidad de Salamanca, Salamanca, Spain
| | - Yue Shen
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK; BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China; Guangdong Provincial Key Laboratory of Genome Read and Write, BGI-Shenzhen, Shenzhen 518120, China
| | - Conrad A Nieduszynski
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK; School of Biological Sciences, University of East Anglia, Norwich NR4 7TU, UK
| | - Romain Koszul
- Institut Pasteur, CNRS UMR 3525, Université Paris Cité, Unité Régulation Spatiale des Génomes, 75015 Paris, France
| | - Junbiao Dai
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Lars M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Germany; Department of Genetics and Stanford Genome Technology Center, Stanford University, Palo Alto, CA 94304, USA
| | - Jef D Boeke
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Yizhi Cai
- Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK.
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4
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Lancaster L, Patel H, Kelly G, Uhlmann F. A role for condensin in mediating transcriptional adaptation to environmental stimuli. Life Sci Alliance 2021; 4:e202000961. [PMID: 34083394 PMCID: PMC8200293 DOI: 10.26508/lsa.202000961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 01/04/2023] Open
Abstract
Nuclear organisation shapes gene regulation; however, the principles by which three-dimensional genome architecture influences gene transcription are incompletely understood. Condensin is a key architectural chromatin constituent, best known for its role in mitotic chromosome condensation. Yet at least a subset of condensin is bound to DNA throughout the cell cycle. Studies in various organisms have reported roles for condensin in transcriptional regulation, but no unifying mechanism has emerged. Here, we use rapid conditional condensin depletion in the budding yeast Saccharomyces cerevisiae to study its role in transcriptional regulation. We observe a large number of small gene expression changes, enriched at genes located close to condensin-binding sites, consistent with a possible local effect of condensin on gene expression. Furthermore, nascent RNA sequencing reveals that transcriptional down-regulation in response to environmental stimuli, in particular to heat shock, is subdued without condensin. Our results underscore the multitude by which an architectural chromosome constituent can affect gene regulation and suggest that condensin facilitates transcriptional reprogramming as part of adaptation to environmental changes.
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Affiliation(s)
- Lucy Lancaster
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
| | - Harshil Patel
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Gavin Kelly
- Bioinformatics and Biostatistics Science Technology Platform, The Francis Crick Institute, London, UK
| | - Frank Uhlmann
- Chromosome Segregation Laboratory, The Francis Crick Institute, London, UK
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5
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Tavares MJ, Güldener U, Mendes-Ferreira A, Mira NP. Genome sequencing, annotation and exploration of the SO 2-tolerant non-conventional yeast Saccharomycodes ludwigii. BMC Genomics 2021; 22:131. [PMID: 33622260 PMCID: PMC7903802 DOI: 10.1186/s12864-021-07438-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 02/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Saccharomycodes ludwigii belongs to the poorly characterized Saccharomycodeacea family and is known by its ability to spoil wines, a trait mostly attributable to its high tolerance to sulfur dioxide (SO2). To improve knowledge about Saccharomycodeacea our group determined whole-genome sequences of Hanseniaspora guilliermondii (UTAD222) and S. ludwigii (UTAD17), two members of this family. While in the case of H. guilliermondii the genomic information elucidated crucial aspects concerning the physiology of this species in the context of wine fermentation, the draft sequence obtained for S. ludwigii was distributed by more than 1000 contigs complicating extraction of biologically relevant information. In this work we describe the results obtained upon resequencing of S. ludwigii UTAD17 genome using PacBio as well as the insights gathered from the exploration of the annotation performed over the assembled genome. RESULTS Resequencing of S. ludwigii UTAD17 genome with PacBio resulted in 20 contigs totaling 13 Mb of assembled DNA and corresponding to 95% of the DNA harbored by this strain. Annotation of the assembled UTAD17 genome predicts 4644 protein-encoding genes. Comparative analysis of the predicted S. ludwigii ORFeome with those encoded by other Saccharomycodeacea led to the identification of 213 proteins only found in this species. Among these were six enzymes required for catabolism of N-acetylglucosamine, four cell wall β-mannosyltransferases, several flocculins and three acetoin reductases. Different from its sister Hanseniaspora species, neoglucogenesis, glyoxylate cycle and thiamine biosynthetic pathways are functional in S. ludwigii. Four efflux pumps similar to the Ssu1 sulfite exporter, as well as robust orthologues for 65% of the S. cerevisiae SO2-tolerance genes, were identified in S. ludwigii genome. CONCLUSIONS This work provides the first genome-wide picture of a S. ludwigii strain representing a step forward for a better understanding of the physiology and genetics of this species and of the Saccharomycodeacea family. The release of this genomic sequence and of the information extracted from it can contribute to guide the design of better wine preservation strategies to counteract spoilage prompted by S. ludwigii. It will also accelerate the exploration of this species as a cell factory, specially in production of fermented beverages where the use of Non-Saccharomyces species (including spoilage species) is booming.
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Affiliation(s)
- Maria J Tavares
- Department of Bioengineering, iBB- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001, Lisbon, Portugal
| | - Ulrich Güldener
- Department of Bioinformatics, Wissenschaftszentrum Weihenstephan, Technische Universität München, Maximus von-Imhof- Forum 3, 85354, Freising, Germany
| | - Ana Mendes-Ferreira
- WM&B - Laboratory of Wine Microbiology & Biotechnology, Department of Biology and Environment, University of Trás-os-Montes and Alto Douro, 5001-801, Vila Real, Portugal. .,BioISI - Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Nuno P Mira
- Department of Bioengineering, iBB- Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001, Lisbon, Portugal.
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6
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Geronikou A, Srimahaeak T, Rantsiou K, Triantafillidis G, Larsen N, Jespersen L. Occurrence of Yeasts in White-Brined Cheeses: Methodologies for Identification, Spoilage Potential and Good Manufacturing Practices. Front Microbiol 2020; 11:582778. [PMID: 33178163 PMCID: PMC7593773 DOI: 10.3389/fmicb.2020.582778] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 09/14/2020] [Indexed: 01/30/2023] Open
Abstract
Yeasts are generally recognized as contaminants in the production of white-brined cheeses, such as Feta and Feta-type cheeses. The most predominant yeasts species are Debaryomyces hansenii, Geotrichum candidum, Kluyveromyces marxianus, Kluyveromyces lactis, Rhodotorula mucilaginosa, and Trichosporon spp. Although their spoilage potential varies at both species and strain levels, yeasts will, in case of excessive growth, present a microbiological hazard, effecting cheese quality. To evaluate the hazard and trace routes of contamination, the exact taxonomic classification of yeasts is required. Today, identification of dairy yeasts is mainly based on DNA sequencing, various genotyping techniques, and, to some extent, advanced phenotypic identification technologies. Even though these technologies are state of the art at the scientific level, they are only hardly implemented at the industrial level. Quality defects, caused by yeasts in white-brined cheese, are mainly linked to enzymatic activities and metabolism of fermentable carbohydrates, leading to production of metabolites (CO2, fatty acids, volatile compounds, amino acids, sulfur compounds, etc.) and resulting in off-flavors, texture softening, discoloration, and swelling of cheese packages. The proliferation of spoilage yeast depends on maturation and storage conditions at each specific dairy, product characteristics, nutrients availability, and interactions with the co-existing microorganisms. To prevent and control yeast contamination, different strategies based on the principles of HACCP and Good Manufacturing Practice (GMP) have been introduced in white-brined cheese production. These strategies include milk pasteurization, refrigeration, hygienic sanitation, air filtration, as well as aseptic and modified atmosphere packaging. Though a lot of research has been dedicated to yeasts in dairy products, the role of yeast contaminants, specifically in white-brined cheeses, is still insufficiently understood. This review aims to summarize the current knowledge on the identification of contaminant yeasts in white-brined cheeses, their occurrence and spoilage potential related to different varieties of white-brined cheeses, their interactions with other microorganisms, as well as guidelines used by dairies to prevent cheese contamination.
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Affiliation(s)
- Athina Geronikou
- Department of Food Science, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Thanyaporn Srimahaeak
- Department of Food Science, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Kalliopi Rantsiou
- Department of Agricultural, Forestry and Food Sciences, University of Turin, Turin, Italy
| | | | - Nadja Larsen
- Department of Food Science, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Lene Jespersen
- Department of Food Science, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
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7
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Falquet B, Ölmezer G, Enkner F, Klein D, Challa K, Appanah R, Gasser SM, Rass U. Disease-associated DNA2 nuclease-helicase protects cells from lethal chromosome under-replication. Nucleic Acids Res 2020; 48:7265-7278. [PMID: 32544229 PMCID: PMC7367196 DOI: 10.1093/nar/gkaa524] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 05/21/2020] [Accepted: 06/09/2020] [Indexed: 01/28/2023] Open
Abstract
DNA2 is an essential nuclease–helicase implicated in DNA repair, lagging-strand DNA synthesis, and the recovery of stalled DNA replication forks (RFs). In Saccharomyces cerevisiae, dna2Δ inviability is reversed by deletion of the conserved helicase PIF1 and/or DNA damage checkpoint-mediator RAD9. It has been suggested that Pif1 drives the formation of long 5′-flaps during Okazaki fragment maturation, and that the essential function of Dna2 is to remove these intermediates. In the absence of Dna2, 5′-flaps are thought to accumulate on the lagging strand, resulting in DNA damage-checkpoint arrest and cell death. In line with Dna2’s role in RF recovery, we find that the loss of Dna2 results in severe chromosome under-replication downstream of endogenous and exogenous RF-stalling. Importantly, unfaithful chromosome replication in Dna2-mutant cells is exacerbated by Pif1, which triggers the DNA damage checkpoint along a pathway involving Pif1’s ability to promote homologous recombination-coupled replication. We propose that Dna2 fulfils its essential function by promoting RF recovery, facilitating replication completion while suppressing excessive RF restart by recombination-dependent replication (RDR) and checkpoint activation. The critical nature of Dna2’s role in controlling the fate of stalled RFs provides a framework to rationalize the involvement of DNA2 in Seckel syndrome and cancer.
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Affiliation(s)
- Benoît Falquet
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Gizem Ölmezer
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Franz Enkner
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Dominique Klein
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Kiran Challa
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland
| | - Rowin Appanah
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, CH-4056 Basel, Switzerland
| | - Ulrich Rass
- Friedrich Miescher Institute for Biomedical Research, CH-4058 Basel, Switzerland.,Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RQ, UK
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8
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Asymmetric Processing of DNA Ends at a Double-Strand Break Leads to Unconstrained Dynamics and Ectopic Translocation. Cell Rep 2019; 24:2614-2628.e4. [PMID: 30184497 DOI: 10.1016/j.celrep.2018.07.102] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/07/2018] [Accepted: 07/27/2018] [Indexed: 01/10/2023] Open
Abstract
Multiple pathways regulate the repair of double-strand breaks (DSBs) to suppress potentially dangerous ectopic recombination. Both sequence and chromatin context are thought to influence pathway choice between non-homologous end-joining (NHEJ) and homology-driven recombination. To test the effect of repetitive sequences on break processing, we have inserted TG-rich repeats on one side of an inducible DSB at the budding yeast MAT locus on chromosome III. Five clustered Rap1 sites within a break-proximal TG repeat are sufficient to block Mre11-Rad50-Xrs2 recruitment, impair resection, and favor elongation by telomerase. The two sides of the break lose end-to-end tethering and show enhanced, uncoordinated movement. Only the TG-free side is resected and shifts to the nuclear periphery. In contrast to persistent DSBs without TG repeats that are repaired by imprecise NHEJ, nearly all survivors of repeat-proximal DSBs repair the break by a homology-driven, non-reciprocal translocation from ChrIII-R to ChrVII-L. This suppression of imprecise NHEJ at TG-repeat-flanked DSBs requires the Uls1 translocase activity.
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9
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Hart RS, Jolly NP, Ndimba BK. Characterisation of hybrid yeasts for the production of varietal Sauvignon blanc wine – A review. J Microbiol Methods 2019; 165:105699. [DOI: 10.1016/j.mimet.2019.105699] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/15/2019] [Accepted: 08/21/2019] [Indexed: 10/26/2022]
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10
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Genetic analyses led to the discovery of a super-active mutant of the RNA polymerase I. PLoS Genet 2019; 15:e1008157. [PMID: 31136569 PMCID: PMC6555540 DOI: 10.1371/journal.pgen.1008157] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 06/07/2019] [Accepted: 04/25/2019] [Indexed: 01/08/2023] Open
Abstract
Most transcriptional activity of exponentially growing cells is carried out by the RNA Polymerase I (Pol I), which produces a ribosomal RNA (rRNA) precursor. In budding yeast, Pol I is a multimeric enzyme with 14 subunits. Among them, Rpa49 forms with Rpa34 a Pol I-specific heterodimer (homologous to PAF53/CAST heterodimer in human Pol I), which might be responsible for the specific functions of the Pol I. Previous studies provided insight in the involvement of Rpa49 in initiation, elongation, docking and releasing of Rrn3, an essential Pol I transcription factor. Here, we took advantage of the spontaneous occurrence of extragenic suppressors of the growth defect of the rpa49 null mutant to better understand the activity of Pol I. Combining genetic approaches, biochemical analysis of rRNA synthesis and investigation of the transcription rate at the individual gene scale, we characterized mutated residues of the Pol I as novel extragenic suppressors of the growth defect caused by the absence of Rpa49. When mapped on the Pol I structure, most of these mutations cluster within the jaw-lobe module, at an interface formed by the lobe in Rpa135 and the jaw made up of regions of Rpa190 and Rpa12. In vivo, the suppressor allele RPA135-F301S restores normal rRNA synthesis and increases Pol I density on rDNA genes when Rpa49 is absent. Growth of the Rpa135-F301S mutant is impaired when combined with exosome mutation rrp6Δ and it massively accumulates pre-rRNA. Moreover, Pol I bearing Rpa135-F301S is a hyper-active RNA polymerase in an in vitro tailed-template assay. We conclude that RNA polymerase I can be engineered to produce more rRNA in vivo and in vitro. We propose that the mutated area undergoes a conformational change that supports the DNA insertion into the cleft of the enzyme resulting in a super-active form of Pol I. The nuclear genome of eukaryotic cells is transcribed by three RNA polymerases. RNA polymerase I (Pol I) is a multimeric enzyme specialized in the synthesis of ribosomal RNA. Deregulation of the Pol I function is linked to the etiology of a broad range of human diseases. Understanding the Pol I activity and regulation represents therefore a major challenge. We chose the budding yeast Saccharomyces cerevisiae as a model, because Pol I transcription apparatus is genetically amenable in this organism. Analyses of phenotypic consequences of deletion/truncation of Pol I subunits-coding genes in yeast indeed provided insights into the activity and regulation of the enzyme. Here, we characterized mutations in Pol I that can alleviate the growth defect caused by the absence of Rpa49, one of the subunits composing this multi-protein enzyme. We mapped these mutations on the Pol I structure and found that they all cluster in a well-described structural element, the jaw-lobe module. Combining genetic and biochemical approaches, we showed that Pol I bearing one of these mutations in the Rpa135 subunit is able to produce more ribosomal RNA in vivo and in vitro. We propose that this super-activity is explained by structural rearrangement of the Pol I jaw/lobe interface.
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11
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Lopez-Canovas L, Martinez Benitez MB, Herrera Isidron JA, Flores Soto E. Pulsed Field Gel Electrophoresis: Past, present, and future. Anal Biochem 2019; 573:17-29. [PMID: 30826351 DOI: 10.1016/j.ab.2019.02.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 12/27/2022]
Abstract
Pulsed Field Gel Electrophoresis (PFGE) has been considered for many years the 'gold-standard' for characterizing many pathogenic organisms as well as for subtyping bacterial species causing infection outbreaks. This article reviews the basic principles of PFGE and it includes the main advantages and limitations of the different electrode configurations that have been used in PFGE equipment and their influence on the DNA electrophoretic separation. Remarkably, we summarize here the most relevant theoretical and practical aspects that we have learned for more than 20 years developing and using the miniaturized PFGE systems. We also discussed the theoretical aspects related to DNA migration in PFGE agarose gels. It served as the basis for simulating the DNA electrophoretic patterns in CHEF mini gels and mini-chambers during experimental design and optimization. A critical comparison between standard and miniaturized PFGE systems, as well as the enzymatic and non-enzymatic methods for intact immobilized DNA preparation, is provided throughout the review. The PFGE current applications, advantages, limitations and future challenges of the methodology are also discussed.
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Affiliation(s)
- Lilia Lopez-Canovas
- Postgraduate Program in Genomic Sciences, School of Science and Technology (CCyT), Autonomous University of Mexico City (UACM), Mexico City, Mexico.
| | - Maximo B Martinez Benitez
- Postgraduate Program in Genomic Sciences, School of Science and Technology (CCyT), Autonomous University of Mexico City (UACM), Mexico City, Mexico.
| | | | - Eduardo Flores Soto
- Academy of Biology, School of Sciences and Humanities, UACM, Mexico City, Mexico.
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12
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Resetting the Yeast Epigenome with Human Nucleosomes. Cell 2017; 171:1508-1519.e13. [PMID: 29198523 DOI: 10.1016/j.cell.2017.10.043] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/11/2017] [Accepted: 10/24/2017] [Indexed: 01/23/2023]
Abstract
Humans and yeast are separated by a billion years of evolution, yet their conserved histones retain central roles in gene regulation. Here, we "reset" yeast to use core human nucleosomes in lieu of their own (a rare event taking 20 days), which initially only worked with variant H3.1. The cells adapt by acquiring suppressor mutations in cell-division genes or by acquiring certain aneuploid states. Converting five histone residues to their yeast counterparts restored robust growth. We reveal that humanized nucleosomes are positioned according to endogenous yeast DNA sequence and chromatin-remodeling network, as judged by a yeast-like nucleosome repeat length. However, human nucleosomes have higher DNA occupancy, globally reduce RNA content, and slow adaptation to new conditions by delaying chromatin remodeling. These humanized yeasts (including H3.3) pose fundamental new questions about how chromatin is linked to many cell processes and provide a platform to study histone variants via yeast epigenome reprogramming.
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13
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Amon JD, Koshland D. RNase H enables efficient repair of R-loop induced DNA damage. eLife 2016; 5. [PMID: 27938663 PMCID: PMC5215079 DOI: 10.7554/elife.20533] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 12/09/2016] [Indexed: 11/13/2022] Open
Abstract
R-loops, three-stranded structures that form when transcripts hybridize to chromosomal DNA, are potent agents of genome instability. This instability has been explained by the ability of R-loops to induce DNA damage. Here, we show that persistent R-loops also compromise DNA repair. Depleting endogenous RNase H activity impairs R-loop removal in Saccharomyces cerevisiae, causing DNA damage that occurs preferentially in the repetitive ribosomal DNA locus (rDNA). We analyzed the repair kinetics of this damage and identified mutants that modulate repair. We present a model that the persistence of R-loops at sites of DNA damage induces repair by break-induced replication (BIR). This R-loop induced BIR is particularly susceptible to the formation of lethal repair intermediates at the rDNA because of a barrier imposed by RNA polymerase I. DOI:http://dx.doi.org/10.7554/eLife.20533.001
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Affiliation(s)
- Jeremy D Amon
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Douglas Koshland
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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El Hage A, Webb S, Kerr A, Tollervey D. Genome-wide distribution of RNA-DNA hybrids identifies RNase H targets in tRNA genes, retrotransposons and mitochondria. PLoS Genet 2014; 10:e1004716. [PMID: 25357144 PMCID: PMC4214602 DOI: 10.1371/journal.pgen.1004716] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 08/27/2014] [Indexed: 01/08/2023] Open
Abstract
During transcription, the nascent RNA can invade the DNA template, forming extended RNA-DNA duplexes (R-loops). Here we employ ChIP-seq in strains expressing or lacking RNase H to map targets of RNase H activity throughout the budding yeast genome. In wild-type strains, R-loops were readily detected over the 35S rDNA region, transcribed by Pol I, and over the 5S rDNA, transcribed by Pol III. In strains lacking RNase H activity, R-loops were elevated over other Pol III genes, notably tRNAs, SCR1 and U6 snRNA, and were also associated with the cDNAs of endogenous TY1 retrotransposons, which showed increased rates of mobility to the 5′-flanking regions of tRNA genes. Unexpectedly, R-loops were also associated with mitochondrial genes in the absence of RNase H1, but not of RNase H2. Finally, R-loops were detected on actively transcribed protein-coding genes in the wild-type, particularly over the second exon of spliced ribosomal protein genes. R-loops (RNA-DNA hybrids) are potentially deleterious for gene expression and genome stability, but can be beneficial, for example, during immunoglobulin gene class-switch recombination. Here we made use of antibody S9.6, with specificity for RNA-DNA duplexes independently of their sequence. The genome-wide distribution of R-loops in wild-type yeast showed association with the highly transcribed ribosomal DNA, and protein-coding genes, particularly the second exon of spliced genes. On RNA polymerase III loci such as the highly transcribed transfer RNA genes (tRNAs), R-loop accumulation was strongly detected in the absence of both ribonucleases H1 and H2 (RNase H1 and H2), indicating that R-loops are inherently formed but rapidly cleared by RNase H. Importantly, stable R-loops lead to reduced synthesis of tRNA precursors in mutants lacking RNase H and DNA topoisomerase activities. RNA-DNA hybrids associated with TY1 cDNA retrotransposition intermediates were elevated in the absence of RNase H, and this was accompanied by increased retrotransposition, in particular to 5′-flanking regions of tRNAs. Our findings show that RNase H participates in silencing of TY1 life cycle. Surprisingly, R-loops associated with mitochondrial transcription units were suppressed specifically by RNase H1. These findings have potentially important implications for understanding human diseases caused by mutations in RNase H.
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Affiliation(s)
- Aziz El Hage
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (AEH); (DT)
| | - Shaun Webb
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Alastair Kerr
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - David Tollervey
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail: (AEH); (DT)
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15
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The nuclear exosome is active and important during budding yeast meiosis. PLoS One 2014; 9:e107648. [PMID: 25210768 PMCID: PMC4161446 DOI: 10.1371/journal.pone.0107648] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/18/2014] [Indexed: 11/19/2022] Open
Abstract
Nuclear RNA degradation pathways are highly conserved across eukaryotes and play important roles in RNA quality control. Key substrates for exosomal degradation include aberrant functional RNAs and cryptic unstable transcripts (CUTs). It has recently been reported that the nuclear exosome is inactivated during meiosis in budding yeast through degradation of the subunit Rrp6, leading to the stabilisation of a subset of meiotic unannotated transcripts (MUTs) of unknown function. We have analysed the activity of the nuclear exosome during meiosis by deletion of TRF4, which encodes a key component of the exosome targeting complex TRAMP. We find that TRAMP mutants produce high levels of CUTs during meiosis that are undetectable in wild-type cells, showing that the nuclear exosome remains functional for CUT degradation, and we further report that the meiotic exosome complex contains Rrp6. Indeed Rrp6 over-expression is insufficient to suppress MUT transcripts, showing that the reduced amount of Rrp6 in meiotic cells does not directly cause MUT accumulation. Lack of TRAMP activity stabilises ∼ 1600 CUTs in meiotic cells, which occupy 40% of the binding capacity of the nuclear cap binding complex (CBC). CBC mutants display defects in the formation of meiotic double strand breaks (DSBs), and we see similar defects in TRAMP mutants, suggesting that a key function of the nuclear exosome is to prevent saturation of the CBC complex by CUTs. Together, our results show that the nuclear exosome remains active in meiosis and has an important role in facilitating meiotic recombination.
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