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Horta MAC, Steenwyk JL, Mead ME, dos Santos LHB, Zhao S, Gibbons JG, Marcet-Houben M, Gabaldón T, Rokas A, Goldman GH. Examination of Genome-Wide Ortholog Variation in Clinical and Environmental Isolates of the Fungal Pathogen Aspergillus fumigatus. mBio 2022; 13:e0151922. [PMID: 35766381 PMCID: PMC9426589 DOI: 10.1128/mbio.01519-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/02/2022] [Indexed: 11/20/2022] Open
Abstract
Aspergillus fumigatus is both an environmental saprobe and an opportunistic human fungal pathogen. Knowledge of genomic variation across A. fumigatus isolates is essential for understanding the evolution of pathogenicity, virulence, and resistance to antifungal drugs. Here, we investigated 206 A. fumigatus isolates (133 clinical and 73 environmental isolates), aiming to identify genes with variable presence across isolates and test whether this variation was related to the clinical or environmental origin of isolates. The PanOrtho genome of A. fumigatus consists of 13,085 ortholog groups, of which 7,773 (59.4%) are shared by all isolates (core groups) and 5,312 (40.6%) vary in their gene presence across isolates (accessory groups plus singletons). Despite differences in the distribution of orthologs across all isolates, no significant differences were observed among clinical versus environmental isolates when phylogeny was accounted for. Orthologs that differ in their distribution across isolates tend to occur at low frequency and/or be restricted to specific isolates; thus, the degree of genomic conservation between orthologs of A. fumigatus is high. These results suggest that differences in the distribution of orthologs within A. fumigatus cannot be associated with the clinical or environmental origin of isolates. IMPORTANCE Aspergillus fumigatus is a cosmopolitan species of fungus responsible for thousands of cases of invasive disease annually. Clinical and environmental isolates of A. fumigatus exhibit extensive phenotypic differences, including differences related to virulence and antifungal drug resistance. A comprehensive survey of the genomic diversity present in A. fumigatus and its relationship to the clinical or environmental origin of isolates can contribute to the prediction of the mechanisms of evolution and infection of the species. Our results suggest that there is no significant variation in ortholog distribution between clinical and environmental isolates when accounting for evolutionary history. The work supports the hypothesis that environmental and clinical isolates of A. fumigatus do not differ in their gene contents.
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Affiliation(s)
- Maria Augusta C. Horta
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Jacob L. Steenwyk
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Matthew E. Mead
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Shu Zhao
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - John G. Gibbons
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
- Organismic and Evolutionary Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts, USA
| | - Marina Marcet-Houben
- Barcelona Supercomputing Centre, Barcelona, Spain
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Toni Gabaldón
- Barcelona Supercomputing Centre, Barcelona, Spain
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
- Centro de Investigación Biomédica En Red de Enfermedades Infecciosas, Barcelona, Spain
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Vanderbilt Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Dolatabadian A, Fernando WGD. Genomic Variations and Mutational Events Associated with Plant-Pathogen Interactions. BIOLOGY 2022; 11:421. [PMID: 35336795 PMCID: PMC8945218 DOI: 10.3390/biology11030421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/07/2022] [Accepted: 03/08/2022] [Indexed: 12/23/2022]
Abstract
Phytopathologists are actively researching the molecular basis of plant-pathogen interactions. The mechanisms of responses to pathogens have been studied extensively in model crop plant species and natural populations. Today, with the rapid expansion of genomic technologies such as DNA sequencing, transcriptomics, proteomics, and metabolomics, as well as the development of new methods and protocols, data analysis, and bioinformatics, it is now possible to assess the role of genetic variation in plant-microbe interactions and to understand the underlying molecular mechanisms of plant defense and microbe pathogenicity with ever-greater resolution and accuracy. Genetic variation is an important force in evolution that enables organisms to survive in stressful environments. Moreover, understanding the role of genetic variation and mutational events is essential for crop breeders to produce improved cultivars. This review focuses on genetic variations and mutational events associated with plant-pathogen interactions and discusses how these genome compartments enhance plants' and pathogens' evolutionary processes.
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Affiliation(s)
- Aria Dolatabadian
- Department of Plant Science, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada;
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Colabardini AC, Wang F, Miao Z, Pardeshi L, Valero C, de Castro PA, Akiyama DY, Tan K, Nora LC, Silva-Rocha R, Marcet-Houben M, Gabaldón T, Fill T, Wong KH, Goldman GH. Chromatin profiling reveals heterogeneity in clinical isolates of the human pathogen Aspergillus fumigatus. PLoS Genet 2022; 18:e1010001. [PMID: 35007279 PMCID: PMC8782537 DOI: 10.1371/journal.pgen.1010001] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 01/21/2022] [Accepted: 12/17/2021] [Indexed: 12/21/2022] Open
Abstract
Invasive Pulmonary Aspergillosis, which is caused by the filamentous fungus Aspergillus fumigatus, is a life-threatening infection for immunosuppressed patients. Chromatin structure regulation is important for genome stability maintenance and has the potential to drive genome rearrangements and affect virulence and pathogenesis of pathogens. Here, we performed the first A. fumigatus global chromatin profiling of two histone modifications, H3K4me3 and H3K9me3, focusing on the two most investigated A. fumigatus clinical isolates, Af293 and CEA17. In eukaryotes, H3K4me3 is associated with active transcription, while H3K9me3 often marks silent genes, DNA repeats, and transposons. We found that H3K4me3 deposition is similar between the two isolates, while H3K9me3 is more variable and does not always represent transcriptional silencing. Our work uncovered striking differences in the number, locations, and expression of transposable elements between Af293 and CEA17, and the differences are correlated with H3K9me3 modifications and higher genomic variations among strains of Af293 background. Moreover, we further showed that the Af293 strains from different laboratories actually differ in their genome contents and found a frequently lost region in chromosome VIII. For one such Af293 variant, we identified the chromosomal changes and demonstrated their impacts on its secondary metabolites production, growth and virulence. Overall, our findings not only emphasize the influence of genome heterogeneity on A. fumigatus fitness, but also caution about unnoticed chromosomal variations among common laboratory strains.
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Affiliation(s)
- Ana Cristina Colabardini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
- Faculty of Health Sciences, University of Macau, Macau SAR of China
| | - Fang Wang
- Faculty of Health Sciences, University of Macau, Macau SAR of China
- Intensive Care Unit, Biomedical Research Center, Shenzhen Institute of Translational Medicine, Shenzhen Second People’s Hospital, The First Affiliated Hospital of Shenzhen University, Shenzhen, China
| | - Zhengqiang Miao
- Faculty of Health Sciences, University of Macau, Macau SAR of China
| | - Lakhansing Pardeshi
- Faculty of Health Sciences, University of Macau, Macau SAR of China
- Genomics, Bioinformatics and Single Cell Analysis Core, Faculty of Health Sciences, University of Macau, Macau SAR of China
| | - Clara Valero
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Daniel Yuri Akiyama
- Instituto de Química, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - Kaeling Tan
- Faculty of Health Sciences, University of Macau, Macau SAR of China
- Genomics, Bioinformatics and Single Cell Analysis Core, Faculty of Health Sciences, University of Macau, Macau SAR of China
| | - Luisa Czamanski Nora
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Rafael Silva-Rocha
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Marina Marcet-Houben
- Barcelona Supercomputing Centre (BSC-CNS). Jordi Girona, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain
| | - Toni Gabaldón
- Barcelona Supercomputing Centre (BSC-CNS). Jordi Girona, Barcelona, Spain
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac, Barcelona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Taicia Fill
- Instituto de Química, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau SAR of China
- Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Macau SAR of China
- MoE Frontiers Science Center for Precision Oncology, University of Macau, Macau SAR of China
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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Long Terminal Repeat Retrotransposon Afut4 Promotes Azole Resistance of Aspergillus fumigatus by Enhancing the Expression of sac1 Gene. Antimicrob Agents Chemother 2021; 65:e0029121. [PMID: 34516252 DOI: 10.1128/aac.00291-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus fumigatus causes a series of invasive diseases, including the high-mortality invasive aspergillosis, and has been a serious global health threat because of its increased resistance to the first-line clinical triazoles. We analyzed the whole-genome sequence of 15 A. fumigatus strains from China and found that long terminal repeat retrotransposons (LTR-RTs), including Afut1, Afut2, Afut3, and Afut4, are most common and have the largest total nucleotide length among all transposable elements in A. fumigatus. Deleting one of the most enriched Afut4977-sac1 in azole-resistant strains decreased azole resistance and downregulated its nearby gene, sac1, but it did not significantly affect the expression of genes of the ergosterol synthesis pathway. We then discovered that 5'LTR of Afut4977-sac1 had promoter activity and enhanced the adjacent sac1 gene expression. We found that sac1 is important to A. fumigatus, and the upregulated sac1 caused elevated resistance of A. fumigatus to azoles. Finally, we showed that Afut4977-sac1 has an evolution pattern similar to that of the whole genome of azole-resistant strains due to azoles; phylogenetic analysis of both the whole genome and Afut4977-sac1 suggests that the insertion of Afut4977-sac1 might have preceded the emergence of azole-resistant strains. Taking these data together, we found that the Afut4977-sac1 LTR-RT might be involved in the regulation of azole resistance of A. fumigatus by upregulating its nearby sac1 gene.
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Arastehfar A, Carvalho A, Houbraken J, Lombardi L, Garcia-Rubio R, Jenks J, Rivero-Menendez O, Aljohani R, Jacobsen I, Berman J, Osherov N, Hedayati M, Ilkit M, Armstrong-James D, Gabaldón T, Meletiadis J, Kostrzewa M, Pan W, Lass-Flörl C, Perlin D, Hoenigl M. Aspergillus fumigatus and aspergillosis: From basics to clinics. Stud Mycol 2021; 100:100115. [PMID: 34035866 PMCID: PMC8131930 DOI: 10.1016/j.simyco.2021.100115] [Citation(s) in RCA: 106] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The airborne fungus Aspergillus fumigatus poses a serious health threat to humans by causing numerous invasive infections and a notable mortality in humans, especially in immunocompromised patients. Mould-active azoles are the frontline therapeutics employed to treat aspergillosis. The global emergence of azole-resistant A. fumigatus isolates in clinic and environment, however, notoriously limits the therapeutic options of mould-active antifungals and potentially can be attributed to a mortality rate reaching up to 100 %. Although specific mutations in CYP 51A are the main cause of azole resistance, there is a new wave of azole-resistant isolates with wild-type CYP 51A genotype challenging the efficacy of the current diagnostic tools. Therefore, applications of whole-genome sequencing are increasingly gaining popularity to overcome such challenges. Prominent echinocandin tolerance, as well as liver and kidney toxicity posed by amphotericin B, necessitate a continuous quest for novel antifungal drugs to combat emerging azole-resistant A. fumigatus isolates. Animal models and the tools used for genetic engineering require further refinement to facilitate a better understanding about the resistance mechanisms, virulence, and immune reactions orchestrated against A. fumigatus. This review paper comprehensively discusses the current clinical challenges caused by A. fumigatus and provides insights on how to address them.
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Affiliation(s)
- A. Arastehfar
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - A. Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's - PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - J. Houbraken
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - L. Lombardi
- UCD Conway Institute and School of Medicine, University College Dublin, Dublin 4, Ireland
| | - R. Garcia-Rubio
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - J.D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Clinical and Translational Fungal-Working Group, University of California San Diego, La Jolla, CA, 92093, USA
| | - O. Rivero-Menendez
- Medical Mycology Reference Laboratory, National Center for Microbiology, Instituto de Salud Carlos III, Madrid, 28222, Spain
| | - R. Aljohani
- Department of Infectious Diseases, Imperial College London, London, UK
| | - I.D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
- Institute for Microbiology, Friedrich Schiller University, Jena, Germany
| | - J. Berman
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knöll Institute, Jena, Germany
| | - N. Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine Ramat-Aviv, Tel-Aviv, 69978, Israel
| | - M.T. Hedayati
- Invasive Fungi Research Center/Department of Medical Mycology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - M. Ilkit
- Division of Mycology, Department of Microbiology, Faculty of Medicine, Çukurova University, 01330, Adana, Turkey
| | | | - T. Gabaldón
- Life Sciences Programme, Supercomputing Center (BSC-CNS), Jordi Girona, Barcelona, 08034, Spain
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB), Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - J. Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - W. Pan
- Medical Mycology, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - C. Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - D.S. Perlin
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, 07110, USA
| | - M. Hoenigl
- Department of Medicine, University of California San Diego, San Diego, CA, 92103, USA
- Section of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Medical University of Graz, 8036, Graz, Austria
- Division of Infectious Diseases and Global Public Health, Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
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Duarte-Escalante E, Frías-De-León MG, Martínez-Herrera E, Acosta-Altamirano G, Rosas de Paz E, Reséndiz-Sánchez J, Refojo N, Reyes-Montes MDR. Identification of CSP Types and Genotypic Variability of Clinical and Environmental Isolates of Aspergillus fumigatus from Different Geographic Origins. Microorganisms 2020; 8:E688. [PMID: 32397318 PMCID: PMC7284390 DOI: 10.3390/microorganisms8050688] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 11/17/2022] Open
Abstract
The CSP (cell surface protein) microsatellite marker is useful for typing Aspergillus fumigatus isolates and determining relationships at the subpopulation level because it has shown high discriminatory power. In the present study, 90 A. fumigatus isolates from Mexico (MX), Argentina (AR), France (FR), and Peru (PE) were identified through a phylogenetic analysis using the benA gene fragment and were typed with the CSP microsatellite, and the types were identified using the nomenclature recommended in the literature. Genetic variability was analyzed through haplotype diversity, nucleotide diversity, polymorphic sites, and nucleotide differences between pairs of sequences. The population structure was evaluated using the Tajima's D statistic. No new CSP types were recorded in the MX, FR, and PE isolates, while in the AR isolates, two new CSP types were identified (t25 and t26). The most common CSP types in the studied populations were t01, t02, t03, and t04A; these results are consistent with findings in other countries. In addition, the genetic diversity parameters we obtained revealed that the greatest genetic diversity was found in the MX population, followed by AR and FR. No population structure was identified among the isolates studied.
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Affiliation(s)
- Esperanza Duarte-Escalante
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria No. 3000, Mexico Cd. Mx. 04510, Mexico; (E.D.-E.); (E.R.d.P.)
| | - María Guadalupe Frías-De-León
- Hospital Regional de Alta Especialidad de Ixtapaluca, Carretera Federal México-Puebla Km. 34.5, Pueblo de Zoquiapan, Ixtapaluca 56530, Mexico; (M.G.F.-D.-L.); (E.M.-H.); (G.A.-A.)
| | - Erick Martínez-Herrera
- Hospital Regional de Alta Especialidad de Ixtapaluca, Carretera Federal México-Puebla Km. 34.5, Pueblo de Zoquiapan, Ixtapaluca 56530, Mexico; (M.G.F.-D.-L.); (E.M.-H.); (G.A.-A.)
| | - Gustavo Acosta-Altamirano
- Hospital Regional de Alta Especialidad de Ixtapaluca, Carretera Federal México-Puebla Km. 34.5, Pueblo de Zoquiapan, Ixtapaluca 56530, Mexico; (M.G.F.-D.-L.); (E.M.-H.); (G.A.-A.)
| | - Emmanuel Rosas de Paz
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria No. 3000, Mexico Cd. Mx. 04510, Mexico; (E.D.-E.); (E.R.d.P.)
| | - Jesús Reséndiz-Sánchez
- Laboratorio de Micología, Hospital Infantil de México “Federico Gómez”, Doctor Márquez 162, Mexico Cd. Mx. 06720, Mexico;
| | - Nicolás Refojo
- Departamento de Micología, Instituto Nacional de Enfermedades Infecciosas ‘Dr. Carlos G. Malbrán’, Buenos Aires C1282AFF, Argentina;
| | - María del Rocío Reyes-Montes
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria No. 3000, Mexico Cd. Mx. 04510, Mexico; (E.D.-E.); (E.R.d.P.)
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7
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Pennerman KK, Gonzalez J, Chenoweth LR, Bennett JW, Yin G, Hua SST. Biocontrol strain Aspergillus flavus WRRL 1519 has differences in chromosomal organization and an increased number of transposon-like elements compared to other strains. Mol Genet Genomics 2018; 293:1507-1522. [DOI: 10.1007/s00438-018-1474-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/10/2018] [Indexed: 12/14/2022]
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Garcia-Rubio R, Escribano P, Gomez A, Guinea J, Mellado E. Comparison of Two Highly Discriminatory Typing Methods to Analyze Aspergillus fumigatus Azole Resistance. Front Microbiol 2018; 9:1626. [PMID: 30079058 PMCID: PMC6062602 DOI: 10.3389/fmicb.2018.01626] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/28/2018] [Indexed: 11/24/2022] Open
Abstract
Aspergillus fumigatus molecular typing has become increasingly more important for detecting outbreaks as well as for local and global epidemiological investigations and surveillance. Over the years, many different molecular methods have been described for genotyping this species. Some outstanding approaches are based on microsatellite markers (STRAf assay, which is the current gold standard), or based on sequencing data (TRESP typing improved in this work with a new marker and was renamed TRESPERG). Both methodologies were used to type a collection of 212 A. fumigatus isolates that included 70 azole resistant strains with diverse resistance mechanisms from different geographic locations. Our results showed that both methods are totally reliable for epidemiological investigations showing similar stratification of the A. fumigatus population. STRAf assay offered higher discriminatory power (D = 0.9993) than the TRESPERG typing method (D = 0.9972), but the latter does not require specific equipment or skilled personnel, allowing for a prompt integration into any clinical microbiology laboratory. Among azole resistant isolates, two groups were differentiated considering their resistance mechanisms: cyp51A single point mutations (G54, M220, or G448), and promoter tandem repeat integrations with or without cyp51A modifications (TR34/L98H, TR46/Y121F/A289T, or TR53). The genotypic differences were assessed to explore the population structure as well as the genetic relationship between strains and their azole resistance profile. Genetic cluster analyses suggested that our A. fumigatus population was formed by 6–7 clusters, depending on the methodology. Also, the azole susceptible and resistance population showed different structure and organization. The combination of both methodologies resolved the population structure in a similar way to what has been described in whole-genome sequencing works.
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Affiliation(s)
- Rocio Garcia-Rubio
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Pilar Escribano
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Ana Gomez
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Jesus Guinea
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.,Department of Medicine, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Emilia Mellado
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
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Abstract
The nuclear ribosomal DNA (rDNA) is considered as a paradigm of concerted evolution. Components of the rDNA tandem repeats (45S) are widely used in phylogenetic studies of different organisms and the internal transcribed spacer (ITS) region was recently selected as a fungal DNA bar code. However, rRNA pseudogenes, as one kind of escape from concerted evolution, were reported in a wide range of organisms, especially in plants and animals. Moreover, large numbers of 5S rRNA pseudogenes were identified in several filamentous ascomycetes. To study whether rDNA evolves in a strict concerted manner and test whether rRNA pseudogenes exist in more species of ascomycetes, intragenomic rDNA polymorphisms were analyzed using whole genome sequences. Divergent rDNA paralogs were found to coexist within a single genome in seven filamentous ascomycetes examined. A great number of paralogs were identified as pseudogenes according to the mutation and secondary structure analyses. Phylogenetic analyses of the three rRNA coding regions of the 45S rDNA repeats, i.e., 18S, 5.8S, and 28S, revealed an interspecies clustering pattern of those different rDNA paralogs. The identified rRNA pseudogenic sequences were validated using specific primers designed. Mutation analyses revealed that the repeat-induced point (RIP) mutation was probably responsible for the formation of those rRNA pseudogenes.
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10
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McAlpin C, Horn B, Wicklow D. DNA fingerprinting analysis of vegetative compatibility groups inAspergillus caelatus. Mycologia 2017. [DOI: 10.1080/15572536.2006.11832840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- C.E. McAlpin
- National Center for Agricultural Utilization Research, USDA, ARS, Peoria, Illinois 61604
| | - B.W. Horn
- National Peanut Laboratory, USDA, ARS, Dawson, Georgia 31742
| | - D.T. Wicklow
- National Center for Agricultural Utilization Research, USDA, ARS, Peoria, Illinois 61604
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11
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Kanhayuwa L, Coutts RHA. Short Interspersed Nuclear Element (SINE) Sequences in the Genome of the Human Pathogenic Fungus Aspergillus fumigatus Af293. PLoS One 2016; 11:e0163215. [PMID: 27736869 PMCID: PMC5063351 DOI: 10.1371/journal.pone.0163215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 09/06/2016] [Indexed: 11/19/2022] Open
Abstract
Novel families of short interspersed nuclear element (SINE) sequences in the human pathogenic fungus Aspergillus fumigatus, clinical isolate Af293, were identified and categorised into tRNA-related and 5S rRNA-related SINEs. Eight predicted tRNA-related SINE families originating from different tRNAs, and nominated as AfuSINE2 sequences, contained target site duplications of short direct repeat sequences (4–14 bp) flanking the elements, an extended tRNA-unrelated region and typical features of RNA polymerase III promoter sequences. The elements ranged in size from 140–493 bp and were present in low copy number in the genome and five out of eight were actively transcribed. One putative tRNAArg-derived sequence, AfuSINE2-1a possessed a unique feature of repeated trinucleotide ACT residues at its 3’-terminus. This element was similar in sequence to the I-4_AO element found in A. oryzae and an I-1_AF long nuclear interspersed element-like sequence identified in A. fumigatus Af293. Families of 5S rRNA-related SINE sequences, nominated as AfuSINE3, were also identified and their 5'-5S rRNA-related regions show 50–65% and 60–75% similarity to respectively A. fumigatus 5S rRNAs and SINE3-1_AO found in A. oryzae. A. fumigatus Af293 contains five copies of AfuSINE3 sequences ranging in size from 259–343 bp and two out of five AfuSINE3 sequences were actively transcribed. Investigations on AfuSINE distribution in the fungal genome revealed that the elements are enriched in pericentromeric and subtelomeric regions and inserted within gene-rich regions. We also demonstrated that some, but not all, AfuSINE sequences are targeted by host RNA silencing mechanisms. Finally, we demonstrated that infection of the fungus with mycoviruses had no apparent effects on SINE activity.
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Affiliation(s)
- Lakkhana Kanhayuwa
- Division of Biology, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, Imperial College Road, London, United Kingdom
- * E-mail:
| | - Robert H. A. Coutts
- Division of Biology, Faculty of Natural Sciences, Imperial College London, Sir Alexander Fleming Building, Imperial College Road, London, United Kingdom
- School of Life and Medical Sciences, Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield, United Kingdom
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A New Aspergillus fumigatus Typing Method Based on Hypervariable Tandem Repeats Located within Exons of Surface Protein Coding Genes (TRESP). PLoS One 2016; 11:e0163869. [PMID: 27701437 PMCID: PMC5049851 DOI: 10.1371/journal.pone.0163869] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/15/2016] [Indexed: 11/19/2022] Open
Abstract
Aspergillus fumigatus is a saprotrophic mold fungus ubiquitously found in the environment and is the most common species causing invasive aspergillosis in immunocompromised individuals. For A. fumigatus genotyping, the short tandem repeat method (STRAf) is widely accepted as the first choice. However, difficulties associated with PCR product size and required technology have encouraged the development of novel typing techniques. In this study, a new genotyping method based on hypervariable tandem repeats within exons of surface protein coding genes (TRESP) was designed. A. fumigatus isolates were characterized by PCR amplification and sequencing with a panel of three TRESP encoding genes: cell surface protein A; MP-2 antigenic galactomannan protein; and hypothetical protein with a CFEM domain. The allele sequence repeats of each of the three targets were combined to assign a specific genotype. For the evaluation of this method, 126 unrelated A. fumigatus strains were analyzed and 96 different genotypes were identified, showing a high level of discrimination [Simpson’s index of diversity (D) 0.994]. In addition, 49 azole resistant strains were analyzed identifying 26 genotypes and showing a lower D value (0.890) among them. This value could indicate that these resistant strains are closely related and share a common origin, although more studies are needed to confirm this hypothesis. In summary, a novel genotyping method for A. fumigatus has been developed which is reproducible, easy to perform, highly discriminatory and could be especially useful for studying outbreaks.
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High-Throughput Construction of Genetically Modified Fungi. Fungal Biol 2016. [DOI: 10.1007/978-3-319-27951-0_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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14
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Teixeira J, Amorim A, Araujo R. Recombination detection in Aspergillus fumigatus through single nucleotide polymorphisms typing. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:881-886. [PMID: 26189756 DOI: 10.1111/1758-2229.12321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 06/27/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
The first evidence of sexual reproduction in Aspergillus fumigatus was reported in 2009. Nevertheless, it remains difficult to understand how A. fumigatus is able to reproduce through this mode in its natural environment and how frequently this occurs. The aim of this study was to analyse single nucleotide polymorphisms (SNPs) in a set of environmental and clinical isolates of A. fumigatus to detect signatures of recombination. A group of closely related Portuguese A. fumigatus isolates was characterized by mating type and the genetic diversity of the intergenic regions, microsatellites and multilocus sequence typing (MLST) genes. A group of 19 SNPs, organized in nine association groups and inherited in blocks, was identified and compared. Several variations on the association panel were detected on reference isolates of A. fumigatus AF293 and A1163, the sequence types available at MLST database and six clinical and environmental Portuguese isolates. About one to four haplotype disruptions were observed per isolate. Considering clinical and environmental isolates, sexual reproduction seems to occur more frequently than previously admitted in A. fumigatus. In this study, a practical SNP approach is proposed for detection of recombination events in larger collections of A. fumigatus.
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Affiliation(s)
- Joana Teixeira
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - António Amorim
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Faculty of Sciences, University of Porto, Porto, Portugal
| | - Ricardo Araujo
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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Amselem J, Lebrun MH, Quesneville H. Whole genome comparative analysis of transposable elements provides new insight into mechanisms of their inactivation in fungal genomes. BMC Genomics 2015. [PMID: 25766680 DOI: 10.1186/s12864-015-1347-1341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
BACKGROUND Transposable Elements (TEs) are key components that shape the organization and evolution of genomes. Fungi have developed defense mechanisms against TE invasion such as RIP (Repeat-Induced Point mutation), MIP (Methylation Induced Premeiotically) and Quelling (RNA interference). RIP inactivates repeated sequences by promoting Cytosine to Thymine mutations, whereas MIP only methylates TEs at C residues. Both mechanisms require specific cytosine DNA Methyltransferases (RID1/Masc1) of the Dnmt1 superfamily. RESULTS We annotated TE sequences from 10 fungal genomes with different TE content (1-70%). We then used these TE sequences to carry out a genome-wide analysis of C to T mutations biases. Genomes from either Ascomycota or Basidiomycota that were massively invaded by TEs (Blumeria, Melampsora, Puccinia) were characterized by a low frequency of C to T mutation bias (10-20%), whereas other genomes displayed intermediate to high frequencies (25-75%). We identified several dinucleotide signatures at these C to T mutation sites (CpA, CpT, and CpG). Phylogenomic analysis of fungal Dnmt1 MTases revealed a previously unreported association between these dinucleotide signatures and the presence/absence of sub-classes of Dnmt1. CONCLUSIONS We identified fungal genomes containing large numbers of TEs with many C to T mutations associated with species-specific dinucleotide signatures. This bias suggests that a basic defense mechanism against TE invasion similar to RIP is widespread in fungi, although the efficiency and specificity of this mechanism differs between species. Our analysis revealed that dinucleotide signatures are associated with the presence/absence of specific Dnmt1 subfamilies. In particular, an RID1-dependent RIP mechanism was found only in Ascomycota.
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Affiliation(s)
- Joëlle Amselem
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Marc-Henri Lebrun
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Hadi Quesneville
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
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Amselem J, Lebrun MH, Quesneville H. Whole genome comparative analysis of transposable elements provides new insight into mechanisms of their inactivation in fungal genomes. BMC Genomics 2015; 16:141. [PMID: 25766680 PMCID: PMC4352252 DOI: 10.1186/s12864-015-1347-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Transposable Elements (TEs) are key components that shape the organization and evolution of genomes. Fungi have developed defense mechanisms against TE invasion such as RIP (Repeat-Induced Point mutation), MIP (Methylation Induced Premeiotically) and Quelling (RNA interference). RIP inactivates repeated sequences by promoting Cytosine to Thymine mutations, whereas MIP only methylates TEs at C residues. Both mechanisms require specific cytosine DNA Methyltransferases (RID1/Masc1) of the Dnmt1 superfamily. RESULTS We annotated TE sequences from 10 fungal genomes with different TE content (1-70%). We then used these TE sequences to carry out a genome-wide analysis of C to T mutations biases. Genomes from either Ascomycota or Basidiomycota that were massively invaded by TEs (Blumeria, Melampsora, Puccinia) were characterized by a low frequency of C to T mutation bias (10-20%), whereas other genomes displayed intermediate to high frequencies (25-75%). We identified several dinucleotide signatures at these C to T mutation sites (CpA, CpT, and CpG). Phylogenomic analysis of fungal Dnmt1 MTases revealed a previously unreported association between these dinucleotide signatures and the presence/absence of sub-classes of Dnmt1. CONCLUSIONS We identified fungal genomes containing large numbers of TEs with many C to T mutations associated with species-specific dinucleotide signatures. This bias suggests that a basic defense mechanism against TE invasion similar to RIP is widespread in fungi, although the efficiency and specificity of this mechanism differs between species. Our analysis revealed that dinucleotide signatures are associated with the presence/absence of specific Dnmt1 subfamilies. In particular, an RID1-dependent RIP mechanism was found only in Ascomycota.
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Affiliation(s)
- Joëlle Amselem
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France. .,INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Marc-Henri Lebrun
- INRA, UR1290 BIOGER, Biologie et gestion des risques en agriculture, Campus AgroParisTech, F-78850, Thiverval-Grignon, France.
| | - Hadi Quesneville
- INRA, UR1164 URGI Research Unit in Genomics-Info, F-78026, Versailles, France.
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17
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Hane JK, Williams AH, Taranto AP, Solomon PS, Oliver RP. Repeat-Induced Point Mutation: A Fungal-Specific, Endogenous Mutagenesis Process. Fungal Biol 2015. [DOI: 10.1007/978-3-319-10503-1_4] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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18
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Abstract
Sexual reproduction is ubiquitous throughout the eukaryotic kingdom, but the capacity of pathogenic fungi to undergo sexual reproduction has been a matter of intense debate. Pathogenic fungi maintained a complement of conserved meiotic genes but the populations appeared to be clonally derived. This debate was resolved first with the discovery of an extant sexual cycle and then unisexual reproduction. Unisexual reproduction is a distinct form of homothallism that dispenses with the requirement for an opposite mating type. Pathogenic and nonpathogenic fungi previously thought to be asexual are able to undergo robust unisexual reproduction. We review here recent advances in our understanding of the genetic and molecular basis of unisexual reproduction throughout fungi and the impact of unisex on the ecology and genomic evolution of fungal species.
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Affiliation(s)
- Kevin C Roach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Marianna Feretzaki
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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Jie Jin F, Hara S, Sato A, Koyama Y. Discovery and analysis of an active long terminal repeat-retrotransposable element in Aspergillus oryzae. J GEN APPL MICROBIOL 2014; 60:1-6. [PMID: 24646755 DOI: 10.2323/jgam.60.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Wild-type Aspergillus oryzae RIB40 contains two copies of the AO090005001597 gene. We previously constructed A. oryzae RIB40 strain, RKuAF8B, with multiple chromosomal deletions, in which the AO090005001597 copy number was found to be increased significantly. Sequence analysis indicated that AO090005001597 is part of a putative 6,000-bp retrotransposable element, flanked by two long terminal repeats (LTRs) of 669 bp, with characteristics of retroviruses and retrotransposons, and thus designated AoLTR (A. oryzae LTR-retrotransposable element). AoLTR comprised putative reverse transcriptase, RNase H, and integrase domains. The deduced amino acid sequence alignment of AoLTR showed 94% overall identity with AFLAV, an A. flavus Tf1/sushi retrotransposon. Quantitative real-time RT-PCR showed that AoLTR gene expression was significantly increased in the RKuAF8B, in accordance with the increased copy number. Inverse PCR indicated that the full-length retrotransposable element was randomly integrated into multiple genomic locations. However, no obvious phenotypic changes were associated with the increased AoLTR gene copy number.
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20
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Wakayama M, Shinozaki M, Shibuya K. [How pathologists can contribute diagnosis in medical mycology]. Med Mycol J 2013; 54:27-37. [PMID: 23470952 DOI: 10.3314/mmj.54.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Megumi Wakayama
- Department of Surgical Pathology, Toho University School of Medicine
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21
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Henk DA, Shahar-Golan R, Devi KR, Boyce KJ, Zhan N, Fedorova ND, Nierman WC, Hsueh PR, Yuen KY, Sieu TPM, Kinh NV, Wertheim H, Baker SG, Day JN, Vanittanakom N, Bignell EM, Andrianopoulos A, Fisher MC. Clonality despite sex: the evolution of host-associated sexual neighborhoods in the pathogenic fungus Penicillium marneffei. PLoS Pathog 2012; 8:e1002851. [PMID: 23055919 PMCID: PMC3464222 DOI: 10.1371/journal.ppat.1002851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 06/25/2012] [Indexed: 12/04/2022] Open
Abstract
Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.
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Affiliation(s)
- Daniel A Henk
- Department of Infectious Disease Epidemiology, Imperial College, Norfolk Place, London, United Kingdom.
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22
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Horns F, Petit E, Yockteng R, Hood ME. Patterns of repeat-induced point mutation in transposable elements of basidiomycete fungi. Genome Biol Evol 2012; 4:240-7. [PMID: 22250128 PMCID: PMC3318451 DOI: 10.1093/gbe/evs005] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Transposable elements (TEs) are ubiquitous genomic parasites that have prompted the evolution of genome defense systems that restrict their activity. Repeat-induced point mutation (RIP) is a homology-dependent genome defense that introduces C-to-T transition mutations in duplicated DNA sequences and is thought to control the proliferation of selfish repetitive DNA. Here, we determine the taxonomic distribution of hypermutation patterns indicative of RIP among basidiomycetes. We quantify C-to-T transition mutations in particular di- and trinucleotide target sites for TE-like sequences from nine fungal genomes. We find evidence of RIP-like patterns of hypermutation at TpCpG trinucleotide sites in repetitive sequences from all species of the Pucciniomycotina subphylum of the Basidiomycota, Microbotryum lychnidis-dioicae, Puccinia graminis, Melampsora laricis-populina, and Rhodotorula graminis. In contrast, we do not find evidence for RIP-like hypermutation in four species of the Agaricomycotina and Ustilaginomycotina subphyla of the Basidiomycota. Our results suggest that a RIP-like process and the specific nucleotide context for mutations are conserved within the Pucciniomycotina subphylum. These findings imply that coevolutionary interactions between TEs and a hypermutating genome defense are stable over long evolutionary timescales.
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Molecular epidemiology of Aspergillus fumigatus: an in-depth genotypic analysis of isolates involved in an outbreak of invasive aspergillosis. J Clin Microbiol 2011; 49:3498-503. [PMID: 21832010 DOI: 10.1128/jcm.01159-11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We recently reported an outbreak of invasive aspergillosis in the major heart surgery unit of Hospital Gregorio Marañón, Madrid, Spain (T. Peláez, P. Muñoz, J. Guinea, M. Valerio, M. Giannella, C. H. W. Klaassen, and E. Bouza, Clin. Infect. Dis., in press). Aspergillus fumigatus was isolated from clinical samples from 10 patients admitted to the unit during the outbreak period (surgical wound invasive aspergillosis, n = 2; probable pulmonary invasive aspergillosis, n = 4; colonization, n = 4). In the study described here, we have studied the genotypic diversity of the A. fumigatus isolates found in the air and clinical samples. We used short tandem repeats of A. fumigatus (STRAf) typing to analyze the genotypes found in the 168 available A. fumigatus isolates collected from the clinical samples (n = 109) from the patients and from the environmental samples taken from the air of the unit (n = 59). The genotypic variability of A. fumigatus was higher in environmental than in clinical samples. Intrasample variability was also higher in environmental than in clinical samples: 2 or more different genotypes were found in 26% and 89% of clinical and environmental samples, respectively. We found matches between environmental and clinical isolates in 3 of the 10 patients: 1 patient with postsurgical invasive aspergillosis and 2 patients with probable pulmonary invasive aspergillosis. A total of 7 genotypes from 3 different patients and the air grouped together in 2 clusters. Clonally related genotypes and microvariants were detected in both clinical and environmental samples. STRAf typing proved to be a valuable tool for identifying the source of invasive aspergillosis outbreaks and for studying the genotypic diversity of clinical and environmental A. fumigatus isolates.
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Clutterbuck AJ. Genomic evidence of repeat-induced point mutation (RIP) in filamentous ascomycetes. Fungal Genet Biol 2011; 48:306-26. [PMID: 20854921 DOI: 10.1016/j.fgb.2010.09.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 09/14/2010] [Accepted: 09/14/2010] [Indexed: 11/18/2022]
Affiliation(s)
- A John Clutterbuck
- School of Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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25
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Hane JK, Oliver RP. In silico reversal of repeat-induced point mutation (RIP) identifies the origins of repeat families and uncovers obscured duplicated genes. BMC Genomics 2010; 11:655. [PMID: 21106049 PMCID: PMC3017866 DOI: 10.1186/1471-2164-11-655] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 11/24/2010] [Indexed: 12/31/2022] Open
Abstract
Background Repeat-induced point mutation (RIP) is a fungal genome defence mechanism guarding against transposon invasion. RIP mutates the sequence of repeated DNA and over time renders the affected regions unrecognisable by similarity search tools such as BLAST. Results DeRIP is a new software tool developed to predict the original sequence of a RIP-mutated region prior to the occurrence of RIP. In this study, we apply deRIP to the genome of the wheat pathogen Stagonospora nodorum SN15 and predict the origin of several previously uncharacterised classes of repetitive DNA. Conclusions Five new classes of transposon repeats and four classes of endogenous gene repeats were identified after deRIP. The deRIP process is a new tool for fungal genomics that facilitates the identification and understanding of the role and origin of fungal repetitive DNA. DeRIP is open-source and is available as part of the RIPCAL suite at http://www.sourceforge.net/projects/ripcal.
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Affiliation(s)
- James K Hane
- Faculty of Health Sciences, Murdoch University, Perth, Western Australia, 6150, Australia
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26
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Duarte-Escalante E, Zúñiga G, Ramírez ON, Córdoba S, Refojo N, Arenas R, Delhaes L, Reyes-Montes MDR. Population structure and diversity of the pathogenic fungus Aspergillus fumigatus isolated from different sources and geographic origins. Mem Inst Oswaldo Cruz 2009; 104:427-33. [PMID: 19547867 DOI: 10.1590/s0074-02762009000300005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 03/10/2009] [Indexed: 11/21/2022] Open
Abstract
Fifty-five clinical and environmental Aspergillus fumigatus isolates from Mexico, Argentina, France and Peru were analyzed to determine their genetic variability, reproductive system and level of differentiation using amplified fragment length polymorphism markers. The level of genetic variability was assessed by measuring the percentage of polymorphic loci, number of effective alleles, expected heterozygocity and by performing an association index test (I(A)). The degree of genetic differentiation and variation was determined using analysis of molecular variance at three levels. Using the paired genetic distances, a dendrogram was built to detect the genetic relationship among alleles. Finally, a network of haplotypes was constructed to determine the geographic relationship among them. The results indicate that the clinical isolates have greater genetic variability than the environmental isolates. The I(A) of the clinical and environmental isolates suggests a recombining population structure. The genetic differentiation among isolates and the dendrogram suggest that the groups of isolates are different. The network of haplotypes demonstrates that the majority of the isolates are grouped according to geographic origin.
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Affiliation(s)
- Esperanza Duarte-Escalante
- Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México, DF, México
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27
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Sharpton TJ, Stajich JE, Rounsley SD, Gardner MJ, Wortman JR, Jordar VS, Maiti R, Kodira CD, Neafsey DE, Zeng Q, Hung CY, McMahan C, Muszewska A, Grynberg M, Mandel MA, Kellner EM, Barker BM, Galgiani JN, Orbach MJ, Kirkland TN, Cole GT, Henn MR, Birren BW, Taylor JW. Comparative genomic analyses of the human fungal pathogens Coccidioides and their relatives. Genome Res 2009; 19:1722-31. [PMID: 19717792 DOI: 10.1101/gr.087551.108] [Citation(s) in RCA: 216] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
While most Ascomycetes tend to associate principally with plants, the dimorphic fungi Coccidioides immitis and Coccidioides posadasii are primary pathogens of immunocompetent mammals, including humans. Infection results from environmental exposure to Coccidiodies, which is believed to grow as a soil saprophyte in arid deserts. To investigate hypotheses about the life history and evolution of Coccidioides, the genomes of several Onygenales, including C. immitis and C. posadasii; a close, nonpathogenic relative, Uncinocarpus reesii; and a more diverged pathogenic fungus, Histoplasma capsulatum, were sequenced and compared with those of 13 more distantly related Ascomycetes. This analysis identified increases and decreases in gene family size associated with a host/substrate shift from plants to animals in the Onygenales. In addition, comparison among Onygenales genomes revealed evolutionary changes in Coccidioides that may underlie its infectious phenotype, the identification of which may facilitate improved treatment and prevention of coccidioidomycosis. Overall, the results suggest that Coccidioides species are not soil saprophytes, but that they have evolved to remain associated with their dead animal hosts in soil, and that Coccidioides metabolism genes, membrane-related proteins, and putatively antigenic compounds have evolved in response to interaction with an animal host.
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Affiliation(s)
- Thomas J Sharpton
- Department of Plant and Microbial Biology, University of California, Berkeley, 94720, USA.
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Shinozaki M, Okubo Y, Nakayama H, Mitsuda A, Ide T, Yamagata Murayama S, Shibuya K. Application of in situ hybridization to tissue sections for identification of molds causing invasive fungal infection. ACTA ACUST UNITED AC 2009; 50:75-83. [PMID: 19430181 DOI: 10.3314/jjmm.50.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The present article describes our studies to know the usefulness of in situ hybridization (ISH) to identify various kinds of mold observed in tissue sections and / or cytological preparations from the lesions of patients with invasive fungal infection. To establish the precise procedure for ISH in formalin-fixed and paraffin-embedded sections, various pretreatments were attempted. The condition finally chosen is written here providing a favorable outcome regarding to both intensity and specificity of signals on outline of molds observed in the tissue sections when specimens were treated with both heat and proteinase K and, solutions were adjusted to higher pH value.Therefore, usefulness of promising probes, two each DNA and peptide nucleic acid (PNA) were verified with a favorable pretreatment condition, using lungs of mice experimentally infected and / or those obtained from autopsies with invasive mold infection. As the result, DNA probes targeting alkaline proteinase (ALP) gene and retrotransposon Afut-1 gene of Aspergillus fumigatus showed specific signal intensity for the Aspergillus species and A. fumigatus, respectively. PNA probes for Candida albicans and the Fusarium species also showed satisfactory specificity. We wish to emphasize that ISH can be a valuable tool to identify medically important molds in formalin-fixed and paraffin-embedded tissue sections or cytological preparations.
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Affiliation(s)
- Minoru Shinozaki
- Department of Surgical Pathology, Toho University School of Medicine, 6-11-1 Omori-Nishi, Ota-Ku, Tokyo, Japan
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Ogasawara H, Obata H, Hata Y, Takahashi S, Gomi K. Crawler, a novel Tc1/mariner-type transposable element in Aspergillus oryzae transposes under stress conditions. Fungal Genet Biol 2009; 46:441-9. [DOI: 10.1016/j.fgb.2009.02.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 02/16/2009] [Accepted: 02/23/2009] [Indexed: 10/21/2022]
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30
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de Valk HA, Klaassen CH, Yntema JB, Hebestreit A, Seidler M, Haase G, Müller FM, Meis JF. Molecular typing and colonization patterns of Aspergillus fumigatus in patients with cystic fibrosis. J Cyst Fibros 2009; 8:110-4. [DOI: 10.1016/j.jcf.2008.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 10/16/2008] [Accepted: 10/20/2008] [Indexed: 11/30/2022]
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Hane JK, Oliver RP. RIPCAL: a tool for alignment-based analysis of repeat-induced point mutations in fungal genomic sequences. BMC Bioinformatics 2008; 9:478. [PMID: 19014496 PMCID: PMC2621366 DOI: 10.1186/1471-2105-9-478] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 11/12/2008] [Indexed: 11/13/2022] Open
Abstract
Background Repeat-induced point mutation (RIP) is a fungal-specific genome defence mechanism that alters the sequences of repetitive DNA, thereby inactivating coding genes. Repeated DNA sequences align between mating and meiosis and both sequences undergo C:G to T:A transitions. In most fungi these transitions preferentially affect CpA di-nucleotides thus altering the frequency of certain di-nucleotides in the affected sequences. The majority of previously published in silico analyses were limited to the comparison of ratios of pre- and post-RIP di-nucleotides in putatively RIP-affected sequences – so-called RIP indices. The analysis of RIP is significantly more informative when comparing sequence alignments of repeated sequences. There is, however, a dearth of bioinformatics tools available to the fungal research community for alignment-based RIP analysis of repeat families. Results We present RIPCAL , a software tool for the automated analysis of RIP in fungal genomic DNA repeats, which performs both RIP index and alignment-based analyses. We demonstrate the ability of RIPCAL to detect RIP within known RIP-affected sequences of Neurospora crassa and other fungi. We also predict and delineate the presence of RIP in the genome of Stagonospora nodorum – a Dothideomycete pathogen of wheat. We show that RIP has affected different members of the S. nodorum rDNA tandem repeat to different extents depending on their genomic contexts. Conclusion The RIPCAL alignment-based method has considerable advantages over RIP indices for the analysis of whole genomes. We demonstrate its application to the recently published genome assembly of S. nodorum.
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Affiliation(s)
- James K Hane
- Australian Centre for Necrotrophic Fungal Pathogens, Faculty of Health Sciences, Murdoch University, Murdoch, Australia.
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Lamarre C, Sokol S, Debeaupuis JP, Henry C, Lacroix C, Glaser P, Coppée JY, François JM, Latgé JP. Transcriptomic analysis of the exit from dormancy of Aspergillus fumigatus conidia. BMC Genomics 2008; 9:417. [PMID: 18796135 PMCID: PMC2556354 DOI: 10.1186/1471-2164-9-417] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 09/16/2008] [Indexed: 11/21/2022] Open
Abstract
Background Establishment of aspergillosis is depending upon the exit from dormancy and germination of the conidia of Aspergillus fumigatus in the lung. To gain an understanding of the molecular mechanisms underlying the early steps of conidial germination, we undertook a transcriptomic analysis using macroarrays constructed with PCR fragments from > 3,000 genes (around one third of the annotated A. fumigatus genome). Results Major results of this analysis are the following: (i) conidia stored pre-packaged mRNAs transcripts (27% of genes have transcripts in the resting conidia; (ii) incubation at 37°C in a nutritive medium induced up- and down-regulation of genes: 19% of the total number of genes deposited on the array were up-regulated whereas 22% of the genes with pre-packaged mRNA in the resting conidia were down-regulated; (iii) most modifications were seen during the first 30 min of germination whereas very little modification of gene expression occurred during the following hour; (iv) one-year old conidia and one-week old conidia behaved similarly at transcriptional level. Conclusion Transcriptomic data indicate that the exit from dormancy is associated with a shift from a fermentative metabolism to a respiratory metabolism as well as a trend toward immediate protein synthesis.
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Affiliation(s)
- Claude Lamarre
- Unité des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
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Abstract
Aspergillus species are widely distributed fungi that release large amounts of airborne conidia, which are dispersed in the environment. Several Aspergillus species have been described as human pathogens. Molecular techniques have been developed to investigate the epidemiological relation between environmental and clinical isolates. Several typing methods have been described for Aspergillus species, most of them with reference to Aspergillus fumigatus. Here, we summarise all the different available molecular typing techniques for Aspergillus. The performance of these techniques is evaluated with respect to their practical feasibility, and their interpretation and discriminatory power assessed. For A. fumigatus isolates, a large extent of genetic variability is demonstrated and therefore fingerprinting techniques with high discriminatory power and high reproducibility are required for this species. Afut1-restriction fragment length polymorphism and microsatellite typing showed the highest discriminatory power. In addition, the microsatellites show excellent reproducibility. Other typing techniques are still useful for smaller epidemiological problems and for less well-equipped laboratories.
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Affiliation(s)
- H A de Valk
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
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Lee DW, Freitag M, Selker EU, Aramayo R. A cytosine methyltransferase homologue is essential for sexual development in Aspergillus nidulans. PLoS One 2008; 3:e2531. [PMID: 18575630 PMCID: PMC2432034 DOI: 10.1371/journal.pone.0002531] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 05/08/2008] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The genome defense processes RIP (repeat-induced point mutation) in the filamentous fungus Neurospora crassa, and MIP (methylation induced premeiotically) in the fungus Ascobolus immersus depend on proteins with DNA methyltransferase (DMT) domains. Nevertheless, these proteins, RID and Masc1, respectively, have not been demonstrated to have DMT activity. We discovered a close homologue in Aspergillus nidulans, a fungus thought to have no methylation and no genome defense system comparable to RIP or MIP. PRINCIPAL FINDINGS We report the cloning and characterization of the DNA methyltransferase homologue A (dmtA) gene from Aspergillus nidulans. We found that the dmtA locus encodes both a sense (dmtA) and an anti-sense transcript (tmdA). Both transcripts are expressed in vegetative, conidial and sexual tissues. We determined that dmtA, but not tmdA, is required for early sexual development and formation of viable ascospores. We also tested if DNA methylation accumulated in any of the dmtA/tmdA mutants we constructed, and found that in both asexual and sexual tissues, these mutants, just like wild-type strains, appear devoid of DNA methylation. CONCLUSIONS/SIGNIFICANCE Our results demonstrate that a DMT homologue closely related to proteins implicated in RIP and MIP has an essential developmental function in a fungus that appears to lack both DNA methylation and RIP or MIP. It remains formally possible that DmtA is a bona fide DMT, responsible for trace, undetected DNA methylation that is restricted to a few cells or transient but our work supports the idea that the DMT domain present in the RID/Masc1/DmtA family has a previously undescribed function.
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Affiliation(s)
- Dong W. Lee
- Department of Biology, College of Science, Texas A&M University, College Station, Texas, United States of America
| | - Michael Freitag
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Eric U. Selker
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Rodolfo Aramayo
- Department of Biology, College of Science, Texas A&M University, College Station, Texas, United States of America
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Repeat induced point mutation in two asexual fungi, Aspergillus niger and Penicillium chrysogenum. Curr Genet 2008; 53:287-97. [PMID: 18347798 DOI: 10.1007/s00294-008-0185-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/25/2008] [Accepted: 03/02/2008] [Indexed: 01/28/2023]
Abstract
Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi.
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Hey P, Robson G, Birch M, Bromley M. Characterisation of Aft1 a Fot1/Pogo type transposon of Aspergillus fumigatus. Fungal Genet Biol 2008; 45:117-26. [DOI: 10.1016/j.fgb.2007.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 09/13/2007] [Accepted: 10/16/2007] [Indexed: 01/05/2023]
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37
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Novikova OS, Fet V, Blinov AG. Homology-dependent inactivation of LTR retrotransposons in Aspergillus fumigatus and A. nidulans genomes. Mol Biol 2007. [DOI: 10.1134/s0026893307060039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Riccioni C, Rubini A, Belfiori B, Passeri V, Paolocci F, Arcioni S. Tmt1: the first LTR-retrotransposon from a Tuber spp. Curr Genet 2007; 53:23-34. [PMID: 17972080 DOI: 10.1007/s00294-007-0155-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 09/03/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Retrotransposons are suitable targets for developing molecular markers for population genetics studies. Transposable elements have not yet been isolated from ectomycorrhizal fungi of the genus Tuber. In this paper, we report on the isolation and characterization of Tmt1, an LTR-retrotransposon from Tuber melanosporum. The Tmt1 sequence shows relatedness to Ty3/gypsy retrotransposons from which it differentiates for the presence of a dUTPase extra-domain between protease and reverse transcriptase. Phylogenetic analyses suggest a horizontal transfer of the dUTPase gene (dut) from a fungal host genome. The presence of non-identical LTRs and degenerate ORFs substantiate an ancient integration of Tmt1 in T. melanosporum genome. Furthermore, transcripts analyses proved an inactive status of Tmt1, whereas Southern analysis showed that Tmt1 is a repetitive T. melanosporum species-specific element. Tmt1-based markers will help us to gain more insights into population biology in this fungal species.
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Affiliation(s)
- Claudia Riccioni
- National Research Council, Plant Genetics Institute-Perugia, Perugia Division, Via Madonna Alta 130, 06128 Perugia, Italy
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39
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Novikova OS, Fet V, Blinov AG. LTR retrotransposons in the Aspergillus fumigatus and A. nidulans genomes. Mol Biol 2007. [DOI: 10.1134/s0026893307050081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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40
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Crouch JA, Glasheen BM, Giunta MA, Clarke BB, Hillman BI. The evolution of transposon repeat-induced point mutation in the genome of Colletotrichum cereale: reconciling sex, recombination and homoplasy in an ''asexual" pathogen. Fungal Genet Biol 2007; 45:190-206. [PMID: 17962053 DOI: 10.1016/j.fgb.2007.08.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2007] [Revised: 06/29/2007] [Accepted: 08/03/2007] [Indexed: 12/21/2022]
Abstract
Mobile transposable elements are among the primary drivers of the evolution of eukaryotic genomes. For fungi, repeat-induced point mutation (RIP) silencing minimizes deleterious effects of transposons by mutating multicopy DNA during meiosis. In this study we identify five transposon species from the mitosporic fungus Colletotrichum cereale and report the signature pattern of RIP acting in a lineage-specific manner on 21 of 35 unique transposon copies, providing the first evidence for sexual recombination for this species. Sequence analysis of genomic populations of the retrotransposon Ccret2 showed repeated rounds of RIP mutation acting on different copies of the element. In the RIPped Ccret2 population, there were multiple inferences of incongruence primarily attributed to RIP-induced homoplasy. This study supports the view that the sequence variability of transposon populations in filamentous fungi reflects the activities of evolutionary processes that fall outside of typical phylogenetic or population genetic reconstructions.
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Affiliation(s)
- Jo Anne Crouch
- Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA
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41
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de Ruiter MT, de Valk HA, Meis JFGM, Klaassen CHW. Retrotransposon insertion-site context (RISC) typing: a novel typing method for Aspergillus fumigatus and a convenient PCR alternative to restriction fragment length polymorphism analysis. J Microbiol Methods 2007; 70:528-34. [PMID: 17692974 DOI: 10.1016/j.mimet.2007.06.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Accepted: 06/15/2007] [Indexed: 11/28/2022]
Abstract
Retrotransposon(-like) sequences in Aspergillus fumigatus have been used as typing targets through restriction fragment length polymorphism (RFLP)/Southern blotting approaches. Differences in fingerprints between unrelated isolates are the result of variations in copy-number and differences in the regions flanking the retrotransposon elements. Here, we present retrotransposon insertion-site context (RISC) typing as a novel and convenient PCR-based typing alternative to the RFLP approach. RISC typing aims at amplifying the sequences flanking the retrotransposon-like sequences in A. fumigatus and allows large numbers of isolates to be analyzed in a timely fashion with excellent discriminatory power.
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Affiliation(s)
- Maaike T de Ruiter
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Weg door Jonkerbos 100, 6532 SZ Nijmegen, The Netherlands
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42
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Balajee SA, Tay ST, Lasker BA, Hurst SF, Rooney AP. Characterization of a novel gene for strain typing reveals substructuring of Aspergillus fumigatus across North America. EUKARYOTIC CELL 2007; 6:1392-9. [PMID: 17557880 PMCID: PMC1951133 DOI: 10.1128/ec.00164-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fifty-five epidemiologically linked Aspergillus fumigatus isolates obtained from six nosocomial outbreaks of invasive aspergillosis were subtyped by sequencing the polymorphic region of the gene encoding a putative cell surface protein, Afu3g08990 (denoted as CSP). Comparative sequence analysis showed that genetic diversity was generated in the coding region of this gene by both tandem repeats and point mutations. Each unique sequence in an outbreak cluster was assigned an arbitrary number or CSP sequence type. The CSP typing method was able to identify "clonal" and genotypically distinct A. fumigatus isolates, and the results of this method were concordant with those of another discriminatory genotyping technique, the Afut1 restriction fragment length polymorphism typing method. The novel single-locus sequence typing (CSP typing) strategy appears to be a simple, rapid, discriminatory tool that can be readily shared across laboratories. In addition, we found that A. fumigatus isolates substructured into multiple clades; interestingly, one clade consisted of isolates predominantly representing invasive clinical isolates recovered from cardiac transplant patients from two different outbreak situations. We also found that the A. fumigatus isolate Af293, whose genome has been sequenced, possesses a CSP gene structure that is substantially different from those of the other A. fumigatus strains studied here, highlighting the need for further taxonomic study.
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Affiliation(s)
- S Arunmozhi Balajee
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Mail stop G 11, 1600 Clifton Road, Atlanta, GA 30333, USA.
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43
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Hua SST, Tarun AS, Pandey SN, Chang L, Chang PK. Characterization of AFLAV, a Tf1/Sushi retrotransposon from Aspergillus flavus. Mycopathologia 2007; 163:97-104. [PMID: 17286166 DOI: 10.1007/s11046-006-0088-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Accepted: 12/28/2006] [Indexed: 10/23/2022]
Abstract
The plasmid, pAF28, a genomic clone from Aspergillus flavus NRRL 6541, has been used as a hybridization probe to fingerprint A. flavus strains isolated in corn and peanut fields. The insert of pAF28 contains a 4.5 kb region which encodes a truncated retrotransposon (AfRTL-1). In search for a full-length and intact copy of retrotransposon, we exploited a novel PCR cloning strategy by amplifying a 3.4 kb region from the genomic DNA of A. flavus NRRL 6541. The fragment was cloned into pCR 4-TOPO. Sequence analysis confirmed that this region encoded putative domains of partial reverse transcriptase, RNase H, and integrase of the predicted retrotransposon. The two flanking long terminal repeats (LTRs) and the sequence between them comprise a putative full-length LTR retrotransposon of 7799 bp in length. This intact retrotransposon sequence is named AFLAV (A. flavus Retrotransposon). The order of the predicted catalytic domains in the polyprotein (Pol) placed AFLAV in the Tf1/sushi subgroup of the Ty3/gypsy retrotransposon family. Primers derived from AFLAV sequence were used to screen this retrotransposon in other strains of A. flavus. More than fifty strains of A. flavus isolated from different geological origins were surveyed and the results show that many strains have extensive deletions in the regions encoding the capsid (Gag) and Pol.
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Affiliation(s)
- Sui-Sheng T Hua
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
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44
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Montiel MD, Lee HA, Archer DB. Evidence of RIP (repeat-induced point mutation) in transposase sequences of Aspergillus oryzae. Fungal Genet Biol 2006; 43:439-45. [PMID: 16531081 DOI: 10.1016/j.fgb.2006.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 01/06/2006] [Accepted: 01/26/2006] [Indexed: 11/20/2022]
Abstract
A DNA methyl-binding column was used to isolate genomic fragments enriched for DNA-methylation from Aspergillus parasiticus. One of the isolated sequences presented 67% identity at the protein level with the transposase from the transposable element Tan1 of Aspergillus niger var. awamori, and was found to be present in at least 20 copies in the Aspergillus oryzae database. Analysis of four copies showed evidence of C:G to T:A transitions in at least 98.2% of the mutations found over a 1,032-1,180 bp region spanning a large part of the transposase sequence. Using copy specific primers three sequences were amplified from a different strain of A. oryzae and a similar pattern of C:G to T:A transitions was found. These transitions are similar to those observed in RIP, in Neurospora crassa, where cytosine-methylation is believed to be involved. Using methylation-sensitive Southern blotting, no evidence of methylation was found in the transposase sequences in these two A. oryzae strains as well as one A. parasiticus and one Aspergillus flavus strain.
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Affiliation(s)
- Maria D Montiel
- Institute of Genetics, School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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45
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Abstract
Aspergillus spp. have been the subject of numerous epidemiological studies. The most useful typing techniques are DNA based methods including the random amplified polymorphic DNA technique, microsatellite length polymorphisms, restriction fragment length polymorphism (RFLP) analysis using retrotransposon-like sequences as probes, and multilocus sequence typing. The results of typing clinical isolates indicate that most of the invasive aspergillosis (IA) patients were infected by a single strain. Genetic analysis could not discriminate between clinical and environmental isolates of Aspergillus. fumigatus, indicating that every strain present in the environment is a potential pathogen if it encounters the appropriate host. The source of infection can also be monitored by typing. Typing studies led to the discovery of a new pathogenic species, A. lentulus, and to the identification of several species not known previously to be pathogenic. Typing studies revealed the existence of two genetically isolated groups within a global A. fumigatus population. Aspergillus fumigatus was found to be the first example of a true cosmopolitan fungus. Additionally, the results obtained in several studies support the premise that recombination played an important role in A. fumigatus populations. The discovery of functional mating type genes in A. fumigatus indicates that past or recent sexual processes could be responsible for the observed recombining population structure.
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Affiliation(s)
- János Varga
- Department of Microbiology, Faculty of Sciences, University of Szeged, Szeged, Hungary
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46
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Fávaro LCDL, Araújo WLD, Azevedo JLD, Paccola-Meirelles LD. The biology and potential for genetic research of transposable elements in filamentous fungi. Genet Mol Biol 2005. [DOI: 10.1590/s1415-47572005000500024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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47
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Monroy F, Sheppard DC. Taf1: a class II transposon of Aspergillus fumigatus. Fungal Genet Biol 2005; 42:638-45. [PMID: 15896988 DOI: 10.1016/j.fgb.2005.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2005] [Revised: 03/29/2005] [Accepted: 04/02/2005] [Indexed: 12/01/2022]
Abstract
Aspergillus fumigatus is an important medical pathogen that lacks a known sexual cycle. Transposons may provide an important mechanism for the generation of genetic diversity in this organism. Here, we describe Taf1, the first class II transposon to be identified in A. fumigatus. Taf1, a member of the mariner superfamily and pogo family of transposons, is distinguished by the presence of extremely long (89 bp) inverted repeats that flank the transposase coding sequence. Taf1 is present in different locations and copy number among clinical strains of A. fumigatus and is transcribed. Analysis of multiple insertion sequences within a single strain suggests that Taf1 elements undergo inactivation by a repeat induced polymorphism-like mechanism. Taf1 insertion patterns were extremely stable despite multiple stressors including heat shock, serial passage, and infection in mice. Thus Taf1 may be useful for strain identification and molecular typing.
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Affiliation(s)
- Franz Monroy
- Division of Infectious Diseases, Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
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48
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de Valk HA, Meis JFGM, Curfs IM, Muehlethaler K, Mouton JW, Klaassen CHW. Use of a novel panel of nine short tandem repeats for exact and high-resolution fingerprinting of Aspergillus fumigatus isolates. J Clin Microbiol 2005; 43:4112-20. [PMID: 16081958 PMCID: PMC1233892 DOI: 10.1128/jcm.43.8.4112-4120.2005] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here we describe a new panel of short tandem repeats (STRs) for a novel exact typing assay that can be used to discriminate between Aspergillus fumigatus isolates. A total of nine STR markers were selected from available genomic A. fumigatus sequences and were divided into three multicolor multiplex PCRs. Each multiplex reaction amplified three di-, tri-, or tetranucleotide repeats, respectively. All nine STR markers were used to analyze 100 presumably unrelated A. fumigatus isolates. For each marker, between 11 and 37 alleles were found in this population. One isolate proved to be a mixture of at least two different isolates. With the remaining 99 isolates, 96 different fingerprinting profiles were obtained. The Simpson's diversity index for the individual markers ranged from 0.77 to 0.97. The diversity index for the multiplex combination of di-, tri-, and tetranucleotide repeats ranged from 0.9784 to 0.9968. The combination of all nine markers yielded a Simpson's diversity index of 0.9994, indicative of the high discriminatory power of these new loci. In theory, this panel of markers is able to discriminate between no less than 27 x 10(9) different genotypes. The multicolor multiplex approach allows large numbers of markers to be tested in a short period of time. The exact nature of the assay combines high reproducibility with the easy exchange of results and makes it a very suitable tool for large-scale epidemiological studies.
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Affiliation(s)
- Hanneke A. de Valk
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Jacques F. G. M. Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Ilse M. Curfs
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Konrad Muehlethaler
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Johan W. Mouton
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Corné H. W. Klaassen
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
- Corresponding author. Mailing address: Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands. Phone: 31-24-3657514. Fax: 31-24-3657516. E-mail:
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49
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Hood ME, Katawczik M, Giraud T. Repeat-induced point mutation and the population structure of transposable elements in Microbotryum violaceum. Genetics 2005; 170:1081-9. [PMID: 15911572 PMCID: PMC1451165 DOI: 10.1534/genetics.105.042564] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Repeat-induced point mutation (RIP) is a genome defense in fungi that hypermutates repetitive DNA and is suggested to limit the accumulation of transposable elements. The genome of Microbotryum violaceum has a high density of transposable elements compared to other fungi, but there is also evidence of RIP activity. This is the first report of RIP in a basidiomycete and was obtained by sequencing multiple copies of the integrase gene of a copia-type transposable element and the helicase gene of a Helitron-type element. In M. violaceum, the targets for RIP mutations are the cytosine residues of TCG trinucleotide combinations. Although RIP is a linkage-dependent process that tends to increase the variation among repetitive sequences, a chromosome-specific substructuring was observed in the transposable element population. The observed chromosome-specific patterns are not consistent with RIP, but rather suggest an effect of gene conversion, which is also a linkage-dependent process but results in a homogenization of repeated sequences. Particular sequences were found more widely distributed within the genome than expected by chance and may reflect the recently active variants. Therefore, sequence variation of transposable elements in M. violaceum appears to be driven by selection for transposition ability in combination with the context-specific forces of the RIP and gene conversion.
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Affiliation(s)
- Michael E Hood
- Department of Biology, University of Virginia, Charlottesville, Virginia 22903, USA.
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50
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Jin J, Lee YK, Wickes BL. Simple chemical extraction method for DNA isolation from Aspergillus fumigatus and other Aspergillus species. J Clin Microbiol 2004; 42:4293-6. [PMID: 15365025 PMCID: PMC516345 DOI: 10.1128/jcm.42.9.4293-4296.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA was successfully isolated from numerous Aspergillus spp. by use of a commercial kit. DNA that was easily digested and yielded PCR products up to 8.5 kb in size was recovered from broth or agar cultures. The ease and speed of this protocol provide an alternative to physical methods of DNA isolation.
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Affiliation(s)
- J Jin
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
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