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Abramczyk D, Del Carmen Sanchez Olmos M, Rojas AAR, Schindler D, Robertson D, McColm S, Marston AL, Barlow PN. A supernumerary synthetic chromosome in Komagataella phaffii as a repository for extraneous genetic material. Microb Cell Fact 2023; 22:259. [PMID: 38104077 PMCID: PMC10724962 DOI: 10.1186/s12934-023-02262-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/29/2023] [Indexed: 12/19/2023] Open
Abstract
BACKGROUND Komagataella phaffii (Pichia pastoris) is a methylotrophic commercially important non-conventional species of yeast that grows in a fermentor to exceptionally high densities on simple media and secretes recombinant proteins efficiently. Genetic engineering strategies are being explored in this organism to facilitate cost-effective biomanufacturing. Small, stable artificial chromosomes in K. phaffii could offer unique advantages by accommodating multiple integrations of extraneous genes and their promoters without accumulating perturbations of native chromosomes or exhausting the availability of selection markers. RESULTS Here, we describe a linear "nano"chromosome (of 15-25 kb) that, according to whole-genome sequencing, persists in K. phaffii over many generations with a copy number per cell of one, provided non-homologous end joining is compromised (by KU70-knockout). The nanochromosome includes a copy of the centromere from K. phaffii chromosome 3, a K. phaffii-derived autonomously replicating sequence on either side of the centromere, and a pair of K. phaffii-like telomeres. It contains, within its q arm, a landing zone in which genes of interest alternate with long (approx. 1-kb) non-coding DNA chosen to facilitate homologous recombination and serve as spacers. The landing zone can be extended along the nanochromosome, in an inch-worming mode of sequential gene integrations, accompanied by recycling of just two antibiotic-resistance markers. The nanochromosome was used to express PDI, a gene encoding protein disulfide isomerase. Co-expression with PDI allowed the production, from a genomically integrated gene, of secreted murine complement factor H, a plasma protein containing 40 disulfide bonds. As further proof-of-principle, we co-expressed, from a nanochromosome, both PDI and a gene for GFP-tagged human complement factor H under the control of PAOX1 and demonstrated that the secreted protein was active as a regulator of the complement system. CONCLUSIONS We have added K. phaffii to the list of organisms that can produce human proteins from genes carried on a stable, linear, artificial chromosome. We envisage using nanochromosomes as repositories for numerous extraneous genes, allowing intensive engineering of K. phaffii without compromising its genome or weakening the resulting strain.
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Affiliation(s)
| | | | | | - Daniel Schindler
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
| | - Daniel Robertson
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Adele L Marston
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh, UK.
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
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2
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Kramer HM, Cook DE, Seidl MF, Thomma BP. Epigenetic regulation of nuclear processes in fungal plant pathogens. PLoS Pathog 2023; 19:e1011525. [PMID: 37535497 PMCID: PMC10399791 DOI: 10.1371/journal.ppat.1011525] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023] Open
Abstract
Through the association of protein complexes to DNA, the eukaryotic nuclear genome is broadly organized into open euchromatin that is accessible for enzymes acting on DNA and condensed heterochromatin that is inaccessible. Chemical and physical alterations to chromatin may impact its organization and functionality and are therefore important regulators of nuclear processes. Studies in various fungal plant pathogens have uncovered an association between chromatin organization and expression of in planta-induced genes that are important for pathogenicity. This review discusses chromatin-based regulation mechanisms as determined in the fungal plant pathogen Verticillium dahliae and relates the importance of epigenetic transcriptional regulation and other nuclear processes more broadly in fungal plant pathogens.
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Affiliation(s)
- H. Martin Kramer
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
| | - David E. Cook
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Department of Plant Pathology, Kansas State University, Manhattan, Kansas, United States of America
| | - Michael F. Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- Theoretical Biology & Bioinformatics, Department of Biology, Utrecht University, Utrecht, the Netherlands
| | - Bart P.H.J. Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Wageningen, the Netherlands
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
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3
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Vijay N. Loss of inner kinetochore genes is associated with the transition to an unconventional point centromere in budding yeast. PeerJ 2020; 8:e10085. [PMID: 33062452 PMCID: PMC7531349 DOI: 10.7717/peerj.10085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/11/2020] [Indexed: 01/28/2023] Open
Abstract
Background The genomic sequences of centromeres, as well as the set of proteins that recognize and interact with centromeres, are known to quickly diverge between lineages potentially contributing to post-zygotic reproductive isolation. However, the actual sequence of events and processes involved in the divergence of the kinetochore machinery is not known. The patterns of gene loss that occur during evolution concomitant with phenotypic changes have been used to understand the timing and order of molecular changes. Methods I screened the high-quality genomes of twenty budding yeast species for the presence of well-studied kinetochore genes. Based on the conserved gene order and complete genome assemblies, I identified gene loss events. Subsequently, I searched the intergenic regions to identify any un-annotated genes or gene remnants to obtain additional evidence of gene loss. Results My analysis identified the loss of four genes (NKP1, NKP2, CENPL/IML3 and CENPN/CHL4) of the inner kinetochore constitutive centromere-associated network (CCAN/also known as CTF19 complex in yeast) in both the Naumovozyma species for which genome assemblies are available. Surprisingly, this collective loss of four genes of the CCAN/CTF19 complex coincides with the emergence of unconventional centromeres in N. castellii and N. dairenensis. My study suggests a tentative link between the emergence of unconventional point centromeres and the turnover of kinetochore genes in budding yeast.
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Affiliation(s)
- Nagarjun Vijay
- Computational Evolutionary Genomics Lab, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
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4
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Seidl MF, Kramer HM, Cook DE, Fiorin GL, van den Berg GCM, Faino L, Thomma BPHJ. Repetitive Elements Contribute to the Diversity and Evolution of Centromeres in the Fungal Genus Verticillium. mBio 2020; 11:e01714-20. [PMID: 32900804 PMCID: PMC7482064 DOI: 10.1128/mbio.01714-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/05/2020] [Indexed: 02/07/2023] Open
Abstract
Centromeres are chromosomal regions that are crucial for chromosome segregation during mitosis and meiosis, and failed centromere formation can contribute to chromosomal anomalies. Despite this conserved function, centromeres differ significantly between and even within species. Thus far, systematic studies into the organization and evolution of fungal centromeres remain scarce. In this study, we identified the centromeres in each of the 10 species of the fungal genus Verticillium and characterized their organization and evolution. Chromatin immunoprecipitation of the centromere-specific histone CenH3 (ChIP-seq) and chromatin conformation capture (Hi-C) followed by high-throughput sequencing identified eight conserved, large (∼150-kb), AT-, and repeat-rich regional centromeres that are embedded in heterochromatin in the plant pathogen Verticillium dahliae Using Hi-C, we similarly identified repeat-rich centromeres in the other Verticillium species. Strikingly, a single degenerated long terminal repeat (LTR) retrotransposon is strongly associated with centromeric regions in some but not all Verticillium species. Extensive chromosomal rearrangements occurred during Verticillium evolution, of which some could be linked to centromeres, suggesting that centromeres contributed to chromosomal evolution. The size and organization of centromeres differ considerably between species, and centromere size was found to correlate with the genome-wide repeat content. Overall, our study highlights the contribution of repetitive elements to the diversity and rapid evolution of centromeres within the fungal genus VerticilliumIMPORTANCE The genus Verticillium contains 10 species of plant-associated fungi, some of which are notorious pathogens. Verticillium species evolved by frequent chromosomal rearrangements that contribute to genome plasticity. Centromeres are instrumental for separation of chromosomes during mitosis and meiosis, and failed centromere functionality can lead to chromosomal anomalies. Here, we used a combination of experimental techniques to identify and characterize centromeres in each of the Verticillium species. Intriguingly, we could strongly associate a single repetitive element to the centromeres of some of the Verticillium species. The presence of this element in the centromeres coincides with increased centromere sizes and genome-wide repeat expansions. Collectively, our findings signify a role of repetitive elements in the function, organization, and rapid evolution of centromeres in a set of closely related fungal species.
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Affiliation(s)
- Michael F Seidl
- Theoretical Biology & Bioinformatics, Utrecht University, Utrecht, the Netherlands
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
| | - H Martin Kramer
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
| | - David E Cook
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
- Plant Pathology, Kansas State University, Manhattan, Kansas, USA
| | - Gabriel L Fiorin
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
| | | | - Luigi Faino
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
- Environmental Biology Department, Sapienza Università di Roma, Rome, Italy
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University, Wageningen, the Netherlands
- University of Cologne, Institute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
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5
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Abstract
Diversity within the fungal kingdom is evident from the wide range of morphologies fungi display as well as the various ecological roles and industrial purposes they serve. Technological advances, particularly in long-read sequencing, coupled with the increasing efficiency and decreasing costs across sequencing platforms have enabled robust characterization of fungal genomes. These sequencing efforts continue to reveal the rampant diversity in fungi at the genome level. Here, we discuss studies that have furthered our understanding of fungal genetic diversity and genomic evolution. These studies revealed the presence of both small-scale and large-scale genomic changes. In fungi, research has recently focused on many small-scale changes, such as how hypermutation and allelic transmission impact genome evolution as well as how and why a few specific genomic regions are more susceptible to rapid evolution than others. High-throughput sequencing of a diverse set of fungal genomes has also illuminated the frequency, mechanisms, and impacts of large-scale changes, which include chromosome structural variation and changes in chromosome number, such as aneuploidy, polyploidy, and the presence of supernumerary chromosomes. The studies discussed herein have provided great insight into how the architecture of the fungal genome varies within species and across the kingdom and how modern fungi may have evolved from the last common fungal ancestor and might also pave the way for understanding how genomic diversity has evolved in all domains of life.
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Affiliation(s)
- Shelby J. Priest
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Vikas Yadav
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Centre, Durham, NC, USA
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6
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Ola M, O'Brien CE, Coughlan AY, Ma Q, Donovan PD, Wolfe KH, Butler G. Polymorphic centromere locations in the pathogenic yeast Candida parapsilosis. Genome Res 2020; 30:684-696. [PMID: 32424070 PMCID: PMC7263194 DOI: 10.1101/gr.257816.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/24/2020] [Indexed: 11/24/2022]
Abstract
Centromeres pose an evolutionary paradox: strongly conserved in function but rapidly changing in sequence and structure. However, in the absence of damage, centromere locations are usually conserved within a species. We report here that isolates of the pathogenic yeast species Candida parapsilosis show within-species polymorphism for the location of centromeres on two of its eight chromosomes. Its old centromeres have an inverted-repeat (IR) structure, whereas its new centromeres have no obvious structural features but are located within 30 kb of the old site. Centromeres can therefore move naturally from one chromosomal site to another, apparently spontaneously and in the absence of any significant changes in DNA sequence. Our observations are consistent with a model in which all centromeres are genetically determined, such as by the presence of short or long IRs or by the ability to form cruciforms. We also find that centromeres have been hotspots for genomic rearrangements in the C. parapsilosis clade.
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Affiliation(s)
- Mihaela Ola
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Caoimhe E O'Brien
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Y Coughlan
- School of Medicine, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Qinxi Ma
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Paul D Donovan
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kenneth H Wolfe
- School of Medicine, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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7
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Wong CYY, Ling YH, Mak JKH, Zhu J, Yuen KWY. "Lessons from the extremes: Epigenetic and genetic regulation in point monocentromere and holocentromere establishment on artificial chromosomes". Exp Cell Res 2020; 390:111974. [PMID: 32222413 DOI: 10.1016/j.yexcr.2020.111974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 03/16/2020] [Accepted: 03/18/2020] [Indexed: 02/08/2023]
Abstract
The formation of de novo centromeres on artificial chromosomes in humans (HACs) and fission yeast (SpYACs) has provided much insights to the epigenetic and genetic control on regional centromere establishment and maintenance. Similarly, the use of artificial chromosomes in point centromeric budding yeast Saccharomyces cerevisiae (ScYACs) and holocentric Caenorhabditis elegans (WACs) has revealed epigenetic regulation in the originally thought purely genetically-determined point centromeres and some centromeric DNA sequence features in holocentromeres, respectively. These relatively extreme and less characterized centromere organizations, on the endogenous chromosomes and artificial chromosomes, will be discussed and compared to the more well-studied regional centromere systems. This review will highlight some of the common epigenetic and genetic features in different centromere architectures, including the presence of the centromeric histone H3 variant, CENP-A or CenH3, centromeric and pericentric transcription, AT-richness and repetitiveness of centromeric DNA sequences.
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Affiliation(s)
- Charmaine Yan Yu Wong
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Yick Hin Ling
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jason Ka Ho Mak
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Jing Zhu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Karen Wing Yee Yuen
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong.
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8
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Maxwell PH. Diverse transposable element landscapes in pathogenic and nonpathogenic yeast models: the value of a comparative perspective. Mob DNA 2020; 11:16. [PMID: 32336995 PMCID: PMC7175516 DOI: 10.1186/s13100-020-00215-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Genomics and other large-scale analyses have drawn increasing attention to the potential impacts of transposable elements (TEs) on their host genomes. However, it remains challenging to transition from identifying potential roles to clearly demonstrating the level of impact TEs have on genome evolution and possible functions that they contribute to their host organisms. I summarize TE content and distribution in four well-characterized yeast model systems in this review: the pathogens Candida albicans and Cryptococcus neoformans, and the nonpathogenic species Saccharomyces cerevisiae and Schizosaccharomyces pombe. I compare and contrast their TE landscapes to their lifecycles, genomic features, as well as the presence and nature of RNA interference pathways in each species to highlight the valuable diversity represented by these models for functional studies of TEs. I then review the regulation and impacts of the Ty1 and Ty3 retrotransposons from Saccharomyces cerevisiae and Tf1 and Tf2 retrotransposons from Schizosaccharomyces pombe to emphasize parallels and distinctions between these well-studied elements. I propose that further characterization of TEs in the pathogenic yeasts would enable this set of four yeast species to become an excellent set of models for comparative functional studies to address outstanding questions about TE-host relationships.
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9
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Sankaranarayanan SR, Ianiri G, Coelho MA, Reza MH, Thimmappa BC, Ganguly P, Vadnala RN, Sun S, Siddharthan R, Tellgren-Roth C, Dawson TL, Heitman J, Sanyal K. Loss of centromere function drives karyotype evolution in closely related Malassezia species. eLife 2020; 9:e53944. [PMID: 31958060 PMCID: PMC7025860 DOI: 10.7554/elife.53944] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome-chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.
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Affiliation(s)
- Sundar Ram Sankaranarayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Marco A Coelho
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Md Hashim Reza
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Bhagya C Thimmappa
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Promit Ganguly
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | | | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | | | - Christian Tellgren-Roth
- National Genomics Infrastructure, Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala UniversityUppsalaSweden
| | - Thomas L Dawson
- Skin Research Institute Singapore, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- Department of Drug Discovery, Medical University of South Carolina, School of PharmacyCharlestonUnited States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
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10
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Abstract
Magnaporthe oryzae is an important fungal pathogen that causes a loss of 10% to 30% of the annual rice crop due to the devastating blast disease. In most organisms, kinetochores are clustered together or arranged at the metaphase plate to facilitate synchronized anaphase separation of sister chromatids in mitosis. In this study, we showed that the initially clustered kinetochores separate and position randomly prior to anaphase in M. oryzae. Centromeres in M. oryzae occupy large genomic regions and form on AT-rich DNA without any common sequence motifs. Overall, this study identified atypical kinetochore dynamics and mapped functional centromeres in M. oryzae to define the roles of centromeric and pericentric boundaries in kinetochore assembly on epigenetically specified centromere loci. This study should pave the way for further understanding of the contribution of heterochromatin in genome stability and virulence of the blast fungus and its related species of high economic importance. Precise kinetochore-microtubule interactions ensure faithful chromosome segregation in eukaryotes. Centromeres, identified as scaffolding sites for kinetochore assembly, are among the most rapidly evolving chromosomal loci in terms of the DNA sequence and length and organization of intrinsic elements. Neither the centromere structure nor the kinetochore dynamics is well studied in plant-pathogenic fungi. Here, we sought to understand the process of chromosome segregation in the rice blast fungus Magnaporthe oryzae. High-resolution imaging of green fluorescent protein (GFP)-tagged inner kinetochore proteins CenpA and CenpC revealed unusual albeit transient declustering of centromeres just before anaphase separation of chromosomes in M. oryzae. Strikingly, the declustered centromeres positioned randomly at the spindle midzone without an apparent metaphase plate per se. Using CenpA chromatin immunoprecipitation followed by deep sequencing, all seven centromeres in M. oryzae were found to be regional, spanning 57-kb to 109-kb transcriptionally poor regions. Highly AT-rich and heavily methylated DNA sequences were the only common defining features of all the centromeres in rice blast. Lack of centromere-specific DNA sequence motifs or repetitive elements suggests an epigenetic specification of centromere function in M. oryzae. PacBio genome assemblies and synteny analyses facilitated comparison of the centromeric/pericentromeric regions in distinct isolates of rice blast and wheat blast and in Magnaporthiopsis poae. Overall, this study revealed unusual centromere dynamics and precisely identified the centromere loci in the top model fungal pathogens that belong to Magnaporthales and cause severe losses in the global production of food crops and turf grasses.
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11
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Prasad P, Sanyal K, Ghosh SK. Sth1, the Key Subunit of the RSC Chromatin Remodeling Complex, Is Essential in Maintaining Chromosomal Integrity and Mediating High Fidelity Chromosome Segregation in the Human Fungal Pathogen Candida albicans. Front Microbiol 2019; 10:1303. [PMID: 31249561 PMCID: PMC6582774 DOI: 10.3389/fmicb.2019.01303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022] Open
Abstract
Chromatin architecture influences gene expression and makes specialized chromatin domains. Factors including histone variants, histone modifiers and chromatin remodelers that define chromatin architecture impact chromosome related processes in Candida albicans. In this context, we sought to investigate the roles of the ATP-dependent chromatin remodeler, Remodel the Structure of Chromatin (RSC) in chromosome segregation of C. albicans. Sth1 is the key ATPase component of RSC and has profound roles in different cellular processes in Saccharomyces cerevisiae. We demonstrate that STH1 is an essential gene in C. albicans. The depletion of Sth1 induces pseudohyphal cells, abnormal spindle morphology, sensitivity toward anti-mitotic drugs and global cohesion defect suggesting an important role of Sth1 in kinetochore-microtubule related processes in C. albicans. Strikingly, Sth1 is required to maintain clustered kinetochores revealing the fact that RSC is required in kinetochore integrity. Taken together, we show that RSC plays an important role in various chromatin-templated processes including chromosome segregation in C. albicans.
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Affiliation(s)
- Priya Prasad
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Santanu K Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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12
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Coughlan AY, Wolfe KH. The reported point centromeres of
Scheffersomyces stipitis
are retrotransposon long terminal repeats. Yeast 2019; 36:275-283. [DOI: 10.1002/yea.3375] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/20/2018] [Accepted: 12/10/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Aisling Y. Coughlan
- UCD Conway Institute, School of MedicineUniversity College Dublin Dublin 4 Ireland
| | - Kenneth H. Wolfe
- UCD Conway Institute, School of MedicineUniversity College Dublin Dublin 4 Ireland
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14
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A Stable, Autonomously Replicating Plasmid Vector Containing Pichia pastoris Centromeric DNA. Appl Environ Microbiol 2018; 84:AEM.02882-17. [PMID: 29802190 DOI: 10.1128/aem.02882-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 05/20/2018] [Indexed: 01/07/2023] Open
Abstract
The methylotrophic yeast Pichia pastoris is widely used to produce recombinant proteins, taking advantage of this species' high-density cell growth and strong ability to secrete proteins. Circular plasmids containing the P. pastoris-specific autonomously replicating sequence (PARS1) permit transformation of P. pastoris with higher efficiency than obtained following chromosomal integration by linearized DNA. Unfortunately, however, existing autonomously replicating plasmids are known to be inherently unstable. In this study, we used transcriptome sequencing (RNA-seq) data and genome sequence information to independently identify, on each of the four chromosomes, centromeric DNA sequences consisting of long inverted repeat sequences. By examining the chromosome 2 centromeric DNA sequence (Cen2) in detail, we demonstrate that an ∼111-bp region located at one end of the putative centromeric sequence had autonomous replication activity. In addition, the full-length Cen2 sequence, which contains two long inverted repeat sequences and a nonrepetitive central core region, is needed for the accurate replication and distribution of plasmids in P. pastoris Thus, we constructed a new, stable, autonomously replicating plasmid vector that harbors the entire Cen2 sequence; this episome facilitates genetic manipulation in P. pastoris, providing high transformation efficiency and plasmid stability.IMPORTANCE Secretory production of recombinant proteins is the most important application of the methylotrophic yeast Pichia pastoris, a species that permits mass production of heterologous proteins. To date, the genetic engineering of P. pastoris has relied largely on integrative vectors due to the lack of user-friendly tools. Autonomously replicating Pichia plasmids are expected to facilitate genetic manipulation; however, the existing systems, which use autonomously replicating sequences (ARSs) such as the P. pastoris-specific ARS (PARS1), are known to be inherently unstable for plasmid replication and distribution. Recently, the centromeric DNA sequences of P. pastoris were identified in back-to-back studies published by several groups; therefore, a new episomal plasmid vector with centromere DNA as a tool for genetic manipulation of P. pastoris is ready to be developed.
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Abstract
The “centromere paradox” refers to rapidly evolving and highly diverse centromere DNA sequences even in closely related eukaryotes. However, factors contributing to this rapid divergence are largely unknown. Here, we identified large regional, LTR retrotransposon-rich centromeres in a group of human fungal pathogens belonging to the Cryptococcus species complex. We provide evidence that loss-of-functional RNAi machinery and possibly cytosine DNA methylation trigger instability of the genome by activation of centromeric retrotransposons presumably suppressed by RNAi. We propose that RNAi, together with cytosine DNA methylation, serves as a critical determinant that maintains repetitive transposon-rich centromere structures. This study explores the direct link between RNAi and centromere structure evolution. The centromere DNA locus on a eukaryotic chromosome facilitates faithful chromosome segregation. Despite performing such a conserved function, centromere DNA sequence as well as the organization of sequence elements is rapidly evolving in all forms of eukaryotes. The driving force that facilitates centromere evolution remains an enigma. Here, we studied the evolution of centromeres in closely related species in the fungal phylum of Basidiomycota. Using ChIP-seq analysis of conserved inner kinetochore proteins, we identified centromeres in three closely related Cryptococcus species: two of which are RNAi-proficient, while the other lost functional RNAi. We find that the centromeres in the RNAi-deficient species are significantly shorter than those of the two RNAi-proficient species. While centromeres are LTR retrotransposon-rich in all cases, the RNAi-deficient species lost all full-length retroelements from its centromeres. In addition, centromeres in RNAi-proficient species are associated with a significantly higher level of cytosine DNA modifications compared with those of RNAi-deficient species. Furthermore, when an RNAi-proficient Cryptococcus species and its RNAi-deficient mutants were passaged under similar conditions, the centromere length was found to be occasionally shortened in RNAi mutants. In silico analysis of predicted centromeres in a group of closely related Ustilago species, also belonging to the Basidiomycota, were found to have undergone a similar transition in the centromere length in an RNAi-dependent fashion. Based on the correlation found in two independent basidiomycetous species complexes, we present evidence suggesting that the loss of RNAi and cytosine DNA methylation triggered transposon attrition, which resulted in shortening of centromere length during evolution.
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Zhu Y, Engström PG, Tellgren-Roth C, Baudo CD, Kennell JC, Sun S, Billmyre RB, Schröder MS, Andersson A, Holm T, Sigurgeirsson B, Wu G, Sankaranarayanan SR, Siddharthan R, Sanyal K, Lundeberg J, Nystedt B, Boekhout T, Dawson TL, Heitman J, Scheynius A, Lehtiö J. Proteogenomics produces comprehensive and highly accurate protein-coding gene annotation in a complete genome assembly of Malassezia sympodialis. Nucleic Acids Res 2017; 45:2629-2643. [PMID: 28100699 PMCID: PMC5389616 DOI: 10.1093/nar/gkx006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 01/16/2017] [Indexed: 11/23/2022] Open
Abstract
Complete and accurate genome assembly and annotation is a crucial foundation for comparative and functional genomics. Despite this, few complete eukaryotic genomes are available, and genome annotation remains a major challenge. Here, we present a complete genome assembly of the skin commensal yeast Malassezia sympodialis and demonstrate how proteogenomics can substantially improve gene annotation. Through long-read DNA sequencing, we obtained a gap-free genome assembly for M. sympodialis (ATCC 42132), comprising eight nuclear and one mitochondrial chromosome. We also sequenced and assembled four M. sympodialis clinical isolates, and showed their value for understanding Malassezia reproduction by confirming four alternative allele combinations at the two mating-type loci. Importantly, we demonstrated how proteomics data could be readily integrated with transcriptomics data in standard annotation tools. This increased the number of annotated protein-coding genes by 14% (from 3612 to 4113), compared to using transcriptomics evidence alone. Manual curation further increased the number of protein-coding genes by 9% (to 4493). All of these genes have RNA-seq evidence and 87% were confirmed by proteomics. The M. sympodialis genome assembly and annotation presented here is at a quality yet achieved only for a few eukaryotic organisms, and constitutes an important reference for future host-microbe interaction studies.
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Affiliation(s)
- Yafeng Zhu
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, 17121 Solna, Sweden
| | - Pär G Engström
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17121 Solna, Sweden
| | - Christian Tellgren-Roth
- National Genomics Infrastructure, Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, 75108 Uppsala, Sweden
| | - Charles D Baudo
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - John C Kennell
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - R Blake Billmyre
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Markus S Schröder
- School of Biomedical and Biomolecular Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Anna Andersson
- Department of Medicine Solna, Translational Immunology Unit, Karolinska Institutet and University Hospital, 17177 Stockholm, Sweden
| | - Tina Holm
- Department of Medicine Solna, Translational Immunology Unit, Karolinska Institutet and University Hospital, 17177 Stockholm, Sweden
| | - Benjamin Sigurgeirsson
- Science for Life Laboratory, School of Biotechnology, Royal Institute of Technology, 17121 Solna, Sweden
| | - Guangxi Wu
- Computational and Systems Biology, Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), 138672, Singapore
| | - Sundar Ram Sankaranarayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Rahul Siddharthan
- The Institute of Mathematical Sciences/HBNI, Taramani, Chennai 600 113, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
| | - Joakim Lundeberg
- Science for Life Laboratory, School of Biotechnology, Royal Institute of Technology, 17121 Solna, Sweden
| | - Björn Nystedt
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, 75123 Uppsala, Sweden
| | - Teun Boekhout
- CBS-Fungal Biodiversity Centre, Utrecht, 3508, The Netherlands and Institute for Biodiversity and ecosystem Dynamics (IBED), University of Amsterdam, 1012 WX Amsterdam, The Netherlands
| | - Thomas L Dawson
- Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), 138648, Singapore
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Annika Scheynius
- Science for Life Laboratory, Department of Clinical Science and Education, Karolinska Institutet, and Sachs' Children and Youth Hospital, Södersjukhuset, SE-118 83 Stockholm, Sweden
| | - Janne Lehtiö
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, 17121 Solna, Sweden
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17
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Abstract
Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but structurally distinct processes in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation, MAT locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as Kluyveromyces lactis and the methylotrophic yeasts Ogataea polymorpha and Komagataella phaffii. We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching?
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18
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Using human artificial chromosomes to study centromere assembly and function. Chromosoma 2017; 126:559-575. [DOI: 10.1007/s00412-017-0633-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/12/2017] [Accepted: 06/13/2017] [Indexed: 12/13/2022]
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19
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Sturmberger L, Chappell T, Geier M, Krainer F, Day KJ, Vide U, Trstenjak S, Schiefer A, Richardson T, Soriaga L, Darnhofer B, Birner-Gruenberger R, Glick BS, Tolstorukov I, Cregg J, Madden K, Glieder A. Refined Pichia pastoris reference genome sequence. J Biotechnol 2016; 235:121-31. [PMID: 27084056 PMCID: PMC5089815 DOI: 10.1016/j.jbiotec.2016.04.023] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/08/2016] [Accepted: 04/11/2016] [Indexed: 11/16/2022]
Abstract
Strains of the species Komagataella phaffii are the most frequently used "Pichia pastoris" strains employed for recombinant protein production as well as studies on peroxisome biogenesis, autophagy and secretory pathway analyses. Genome sequencing of several different P. pastoris strains has provided the foundation for understanding these cellular functions in recent genomics, transcriptomics and proteomics experiments. This experimentation has identified mistakes, gaps and incorrectly annotated open reading frames in the previously published draft genome sequences. Here, a refined reference genome is presented, generated with genome and transcriptome sequencing data from multiple P. pastoris strains. Twelve major sequence gaps from 20 to 6000 base pairs were closed and 5111 out of 5256 putative open reading frames were manually curated and confirmed by RNA-seq and published LC-MS/MS data, including the addition of new open reading frames (ORFs) and a reduction in the number of spliced genes from 797 to 571. One chromosomal fragment of 76kbp between two previous gaps on chromosome 1 and another 134kbp fragment at the end of chromosome 4, as well as several shorter fragments needed re-orientation. In total more than 500 positions in the genome have been corrected. This reference genome is presented with new chromosomal numbering, positioning ribosomal repeats at the distal ends of the four chromosomes, and includes predicted chromosomal centromeres as well as the sequence of two linear cytoplasmic plasmids of 13.1 and 9.5kbp found in some strains of P. pastoris.
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Affiliation(s)
- Lukas Sturmberger
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria
| | - Thomas Chappell
- BioGrammatics Inc., 2120 Las Palmas Drive, Carlsbad, CA 92011, United States
| | - Martina Geier
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria
| | - Florian Krainer
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Kasey J Day
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th St., Chicago, IL 60637, United States
| | - Ursa Vide
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Sara Trstenjak
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Anja Schiefer
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria
| | - Toby Richardson
- Synthetic Genomics, Inc., 11149 North Torrey Pines Rd., La Jolla, CA 92037, United States
| | - Leah Soriaga
- Synthetic Genomics, Inc., 11149 North Torrey Pines Rd., La Jolla, CA 92037, United States
| | - Barbara Darnhofer
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria; Institute of Pathology, Research Unit Functional Proteomics and Metabolic Pathways, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Ruth Birner-Gruenberger
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria; Institute of Pathology, Research Unit Functional Proteomics and Metabolic Pathways, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Benjamin S Glick
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th St., Chicago, IL 60637, United States
| | - Ilya Tolstorukov
- BioGrammatics Inc., 2120 Las Palmas Drive, Carlsbad, CA 92011, United States; Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, United States
| | - James Cregg
- BioGrammatics Inc., 2120 Las Palmas Drive, Carlsbad, CA 92011, United States; Keck Graduate Institute, 535 Watson Drive, Claremont, CA 91711, United States
| | - Knut Madden
- BioGrammatics Inc., 2120 Las Palmas Drive, Carlsbad, CA 92011, United States
| | - Anton Glieder
- Austrian Center of Industrial Biotechnology (ACIB), Petersgasse 14, 8010 Graz, Austria; Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria; bisy e.U., Wetzawinkel 20, 8200 Hofstaetten/Raab, Austria.
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20
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Coughlan AY, Hanson SJ, Byrne KP, Wolfe KH. Centromeres of the Yeast Komagataella phaffii (Pichia pastoris) Have a Simple Inverted-Repeat Structure. Genome Biol Evol 2016; 8:2482-92. [PMID: 27497317 PMCID: PMC5010909 DOI: 10.1093/gbe/evw178] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Centromere organization has evolved dramatically in one clade of fungi, the Saccharomycotina. These yeasts have lost the ability to make normal eukaryotic heterochromatin with histone H3K9 methylation, which is a major component of pericentromeric regions in other eukaryotes. Following this loss, several different types of centromere emerged, including two types of sequence-defined (“point”) centromeres, and the epigenetically defined “small regional” centromeres of Candida albicans. Here we report that centromeres of the methylotrophic yeast Komagataella phaffii (formerly called Pichia pastoris) are structurally defined. Each of its four centromeres consists of a 2-kb inverted repeat (IR) flanking a 1-kb central core (mid) region. The four centromeres are unrelated in sequence. CenH3 (Cse4) binds strongly to the cores, with a decreasing gradient along the IRs. This mode of organization resembles Schizosaccharomyces pombe centromeres but is much more compact and lacks the extensive flanking heterochromatic otr repeats. Different isolates of K. phaffii show polymorphism for the orientation of the mid regions, due to recombination in the IRs. CEN4 is located within a 138-kb region that changes orientation during mating-type switching, but switching does not induce recombination of centromeric IRs. Our results demonstrate that evolutionary transitions in centromere organization have occurred in multiple yeast clades.
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Affiliation(s)
- Aisling Y Coughlan
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Sara J Hanson
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Kevin P Byrne
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
| | - Kenneth H Wolfe
- UCD Conway Institute, School of Medicine, University College Dublin, Dublin, Ireland
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21
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Chatterjee G, Sankaranarayanan SR, Guin K, Thattikota Y, Padmanabhan S, Siddharthan R, Sanyal K. Repeat-Associated Fission Yeast-Like Regional Centromeres in the Ascomycetous Budding Yeast Candida tropicalis. PLoS Genet 2016; 12:e1005839. [PMID: 26845548 PMCID: PMC4741521 DOI: 10.1371/journal.pgen.1005839] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 01/11/2016] [Indexed: 11/19/2022] Open
Abstract
The centromere, on which kinetochore proteins assemble, ensures precise chromosome segregation. Centromeres are largely specified by the histone H3 variant CENP-A (also known as Cse4 in yeasts). Structurally, centromere DNA sequences are highly diverse in nature. However, the evolutionary consequence of these structural diversities on de novo CENP-A chromatin formation remains elusive. Here, we report the identification of centromeres, as the binding sites of four evolutionarily conserved kinetochore proteins, in the human pathogenic budding yeast Candida tropicalis. Each of the seven centromeres comprises a 2 to 5 kb non-repetitive mid core flanked by 2 to 5 kb inverted repeats. The repeat-associated centromeres of C. tropicalis all share a high degree of sequence conservation with each other and are strikingly diverged from the unique and mostly non-repetitive centromeres of related Candida species--Candida albicans, Candida dubliniensis, and Candida lusitaniae. Using a plasmid-based assay, we further demonstrate that pericentric inverted repeats and the underlying DNA sequence provide a structural determinant in CENP-A recruitment in C. tropicalis, as opposed to epigenetically regulated CENP-A loading at centromeres in C. albicans. Thus, the centromere structure and its influence on de novo CENP-A recruitment has been significantly rewired in closely related Candida species. Strikingly, the centromere structural properties along with role of pericentric repeats in de novo CENP-A loading in C. tropicalis are more reminiscent to those of the distantly related fission yeast Schizosaccharomyces pombe. Taken together, we demonstrate, for the first time, fission yeast-like repeat-associated centromeres in an ascomycetous budding yeast.
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Affiliation(s)
- Gautam Chatterjee
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Sundar Ram Sankaranarayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Krishnendu Guin
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Yogitha Thattikota
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Sreedevi Padmanabhan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Rahul Siddharthan
- The Institute of Mathematical Sciences, C.I.T. Campus, Taramani, Chennai, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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22
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Schotanus K, Soyer JL, Connolly LR, Grandaubert J, Happel P, Smith KM, Freitag M, Stukenbrock EH. Histone modifications rather than the novel regional centromeres of Zymoseptoria tritici distinguish core and accessory chromosomes. Epigenetics Chromatin 2015; 8:41. [PMID: 26430472 PMCID: PMC4589918 DOI: 10.1186/s13072-015-0033-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/21/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Supernumerary chromosomes have been found in many organisms. In fungi, these "accessory" or "dispensable" chromosomes are present at different frequencies in populations and are usually characterized by higher repetitive DNA content and lower gene density when compared to the core chromosomes. In the reference strain of the wheat pathogen, Zymoseptoria tritici, eight discrete accessory chromosomes have been found. So far, no functional role has been assigned to these chromosomes; however, they have existed as separate entities in the karyotypes of Zymoseptoria species over evolutionary time. In this study, we addressed what-if anything-distinguishes the chromatin of accessory chromosomes from core chromosomes. We used chromatin immunoprecipitation combined with high-throughput sequencing ("ChIP-seq") of DNA associated with the centromere-specific histone H3, CENP-A (CenH3), to identify centromeric DNA, and ChIP-seq with antibodies against dimethylated H3K4, trimethylated H3K9 and trimethylated H3K27 to determine the relative distribution and proportion of euchromatin, obligate and facultative heterochromatin, respectively. RESULTS Centromeres of the eight accessory chromosomes have the same sequence composition and structure as centromeres of the 13 core chromosomes and they are of similar length. Unlike those of most other fungi, Z. tritici centromeres are not composed entirely of repetitive DNA; some centromeres contain only unique DNA sequences, and bona fide expressed genes are located in regions enriched with CenH3. By fluorescence microscopy, we showed that centromeres of Z. tritici do not cluster into a single chromocenter during interphase. We found dramatically higher enrichment of H3K9me3 and H3K27me3 on the accessory chromosomes, consistent with the twofold higher proportion of repetitive DNA and poorly transcribed genes. In contrast, no single histone modification tested here correlated with the distribution of centromeric nucleosomes. CONCLUSIONS All centromeres are similar in length and composed of a mixture of unique and repeat DNA, and most contain actively transcribed genes. Centromeres, subtelomeric regions or telomere repeat length cannot account for the differences in transfer fidelity between core and accessory chromosomes, but accessory chromosomes are greatly enriched in nucleosomes with H3K27 trimethylation. Genes on accessory chromosomes appear to be silenced by trimethylation of H3K9 and H3K27.
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Affiliation(s)
- Klaas Schotanus
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Jessica L Soyer
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; INRA, UMR 1290 INRA-AgroParisTech BIOGER, Avenue Lucien Brétignières, Thiverval-Grignon, 78850 France ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Lanelle R Connolly
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Jonathan Grandaubert
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Petra Happel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany
| | - Kristina M Smith
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7303 USA
| | - Eva H Stukenbrock
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Strasse 10, 35043 Marburg, Germany ; Christian-Albrechts University of Kiel, Environmental Genomics, Am Botanischen Garten 9-11, 24118 Kiel, Germany ; Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
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23
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Mitra S, Gómez-Raja J, Larriba G, Dubey DD, Sanyal K. Rad51-Rad52 mediated maintenance of centromeric chromatin in Candida albicans. PLoS Genet 2014; 10:e1004344. [PMID: 24762765 PMCID: PMC3998917 DOI: 10.1371/journal.pgen.1004344] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 03/19/2014] [Indexed: 11/29/2022] Open
Abstract
Specification of the centromere location in most eukaryotes is not solely dependent on the DNA sequence. However, the non-genetic determinants of centromere identity are not clearly defined. While multiple mechanisms, individually or in concert, may specify centromeres epigenetically, most studies in this area are focused on a universal factor, a centromere-specific histone H3 variant CENP-A, often considered as the epigenetic determinant of centromere identity. In spite of variable timing of its loading at centromeres across species, a replication coupled early S phase deposition of CENP-A is found in most yeast centromeres. Centromeres are the earliest replicating chromosomal regions in a pathogenic budding yeast Candida albicans. Using a 2-dimensional agarose gel electrophoresis assay, we identify replication origins (ORI7-LI and ORI7-RI) proximal to an early replicating centromere (CEN7) in C. albicans. We show that the replication forks stall at CEN7 in a kinetochore dependent manner and fork stalling is reduced in the absence of the homologous recombination (HR) proteins Rad51 and Rad52. Deletion of ORI7-RI causes a significant reduction in the stalled fork signal and an increased loss rate of the altered chromosome 7. The HR proteins, Rad51 and Rad52, have been shown to play a role in fork restart. Confocal microscopy shows declustered kinetochores in rad51 and rad52 mutants, which are evidence of kinetochore disintegrity. CENP-ACaCse4 levels at centromeres, as determined by chromatin immunoprecipitation (ChIP) experiments, are reduced in absence of Rad51/Rad52 resulting in disruption of the kinetochore structure. Moreover, western blot analysis reveals that delocalized CENP-A molecules in HR mutants degrade in a similar fashion as in other kinetochore mutants described before. Finally, co-immunoprecipitation assays indicate that Rad51 and Rad52 physically interact with CENP-ACaCse4in vivo. Thus, the HR proteins Rad51 and Rad52 epigenetically maintain centromere functioning by regulating CENP-ACaCse4 levels at the programmed stall sites of early replicating centromeres. The epigenetic mark of centromeres, CENP-A, is deposited in S phase in most yeasts by a mechanism that is not completely understood. Here, we identify two CEN7 flanking replication origins, ORI7-L1 and ORI7-RI, proximal to an early replicating centromere (CEN7) in a budding yeast Candida albicans. Replication forks starting from these origins stall randomly at CEN7 by the kinetochore that serves as a barrier to fork progression. We observe that centromeric fork stalling is reduced in absence of the HR proteins, Rad51 and Rad52, known to play a role in restarting stalled forks. Further, we demonstrate that Rad51 and Rad52 physically interact with CENP-ACaCse4in vivo. CENP-ACaCse4 levels are reduced in absence of Rad51 or Rad52, which results in disruption of the kinetochore structure. Here we propose a novel DNA replication-coupled mechanism mediated by HR proteins which epigenetically maintains centromere identity by regulating CENP-A deposition. A direct role of DNA repair proteins in centromere function offers insights into the mechanisms of centromere mis-regulation that leads to widespread aneuploidy in cancer cells.
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Affiliation(s)
- Sreyoshi Mitra
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Jonathan Gómez-Raja
- Departamento Ciencias Biomédicas Área de Microbiología, Universidad de Extremadura, Badajoz, Spain
| | - Germán Larriba
- Departamento Ciencias Biomédicas Área de Microbiología, Universidad de Extremadura, Badajoz, Spain
| | | | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
- * E-mail:
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Janbon G, Ormerod KL, Paulet D, Byrnes EJ, Yadav V, Chatterjee G, Mullapudi N, Hon CC, Billmyre RB, Brunel F, Bahn YS, Chen W, Chen Y, Chow EWL, Coppée JY, Floyd-Averette A, Gaillardin C, Gerik KJ, Goldberg J, Gonzalez-Hilarion S, Gujja S, Hamlin JL, Hsueh YP, Ianiri G, Jones S, Kodira CD, Kozubowski L, Lam W, Marra M, Mesner LD, Mieczkowski PA, Moyrand F, Nielsen K, Proux C, Rossignol T, Schein JE, Sun S, Wollschlaeger C, Wood IA, Zeng Q, Neuvéglise C, Newlon CS, Perfect JR, Lodge JK, Idnurm A, Stajich JE, Kronstad JW, Sanyal K, Heitman J, Fraser JA, Cuomo CA, Dietrich FS. Analysis of the genome and transcriptome of Cryptococcus neoformans var. grubii reveals complex RNA expression and microevolution leading to virulence attenuation. PLoS Genet 2014; 10:e1004261. [PMID: 24743168 PMCID: PMC3990503 DOI: 10.1371/journal.pgen.1004261] [Citation(s) in RCA: 276] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 02/07/2014] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans is a pathogenic basidiomycetous yeast responsible for more than 600,000 deaths each year. It occurs as two serotypes (A and D) representing two varieties (i.e. grubii and neoformans, respectively). Here, we sequenced the genome and performed an RNA-Seq-based analysis of the C. neoformans var. grubii transcriptome structure. We determined the chromosomal locations, analyzed the sequence/structural features of the centromeres, and identified origins of replication. The genome was annotated based on automated and manual curation. More than 40,000 introns populating more than 99% of the expressed genes were identified. Although most of these introns are located in the coding DNA sequences (CDS), over 2,000 introns in the untranslated regions (UTRs) were also identified. Poly(A)-containing reads were employed to locate the polyadenylation sites of more than 80% of the genes. Examination of the sequences around these sites revealed a new poly(A)-site-associated motif (AUGHAH). In addition, 1,197 miscRNAs were identified. These miscRNAs can be spliced and/or polyadenylated, but do not appear to have obvious coding capacities. Finally, this genome sequence enabled a comparative analysis of strain H99 variants obtained after laboratory passage. The spectrum of mutations identified provides insights into the genetics underlying the micro-evolution of a laboratory strain, and identifies mutations involved in stress responses, mating efficiency, and virulence. Cryptococcus neoformans var. grubii is a major human pathogen responsible for deadly meningoencephalitis in immunocompromised patients. Here, we report the sequencing and annotation of its genome. Evidence for extensive intron splicing, antisense transcription, non-coding RNAs, and alternative polyadenylation indicates the potential for highly intricate regulation of gene expression in this opportunistic pathogen. In addition, detailed molecular, genetic, and genomic studies were performed to characterize structural features of the genome, including centromeres and origins of replication. Finally, the phenotypic and genome re-sequencing analysis of a collection of isolates of the reference H99 strain resulting from laboratory passage revealed that microevolutionary processes during in vitro culturing of pathogenic fungi can impact virulence.
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Affiliation(s)
- Guilhem Janbon
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
- * E-mail: (GJ); (JH); (CAC); (FSD)
| | - Kate L. Ormerod
- University of Queensland, School of Chemistry and Molecular Biosciences, Brisbane, Queensland, Australia
| | - Damien Paulet
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et Génétique, Paris, France
| | - Edmond J. Byrnes
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | - Vikas Yadav
- Jawaharlal Nehru Centre for Advanced Scientific Research, Molecular Biology and Genetics Unit, Bangalore, India
| | - Gautam Chatterjee
- Jawaharlal Nehru Centre for Advanced Scientific Research, Molecular Biology and Genetics Unit, Bangalore, India
| | | | - Chung-Chau Hon
- Institut Pasteur, Unité Biologie Cellulaire du Parasitisme, Département Biologie Cellulaire et Infection, Paris, France
| | - R. Blake Billmyre
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | | | - Yong-Sun Bahn
- Yonsei University, Center for Fungal Pathogenesis, Department of Biotechnology, Seoul, Republic of Korea
| | - Weidong Chen
- Rutgers New Jersey Medical School, Department of Microbiology and Molecular Genetics, Newark, New Jersey, United States of America
| | - Yuan Chen
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | - Eve W. L. Chow
- University of Queensland, School of Chemistry and Molecular Biosciences, Brisbane, Queensland, Australia
| | - Jean-Yves Coppée
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et Génétique, Paris, France
| | - Anna Floyd-Averette
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | | | - Kimberly J. Gerik
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri, United States of America
| | - Jonathan Goldberg
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Sara Gonzalez-Hilarion
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Sharvari Gujja
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Joyce L. Hamlin
- University of Virginia, Department of Biochemistry and Molecular Genetics, Charlottesville, Virginia, United States of America
| | - Yen-Ping Hsueh
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
- California Institute of Technology, Division of Biology, Pasadena, California, United States of America
| | - Giuseppe Ianiri
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology and Biophysics, Kansas City, Missouri, United States of America
| | - Steven Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Chinnappa D. Kodira
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Lukasz Kozubowski
- Clemson University, Department of Genetics and Biochemistry, Clemson, South Carolina, United States of America
| | - Woei Lam
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri, United States of America
| | - Marco Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Larry D. Mesner
- University of Virginia, Department of Biochemistry and Molecular Genetics, Charlottesville, Virginia, United States of America
| | - Piotr A. Mieczkowski
- University of North Carolina, Department of Genetics, Chapel Hill, North Carolina, United States of America
| | - Frédérique Moyrand
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Kirsten Nielsen
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
- University of Minnesota, Microbiology Department, Minneapolis, Minnesota, United States of America
| | - Caroline Proux
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et Génétique, Paris, France
| | | | - Jacqueline E. Schein
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Sheng Sun
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | - Carolin Wollschlaeger
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Ian A. Wood
- University of Queensland, School of Mathematics and Physics, Brisbane, Queensland, Australia
| | - Qiandong Zeng
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | | | - Carol S. Newlon
- Rutgers New Jersey Medical School, Department of Microbiology and Molecular Genetics, Newark, New Jersey, United States of America
| | - John R. Perfect
- Duke University Medical Center, Duke Department of Medicine and Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
| | - Jennifer K. Lodge
- Washington University School of Medicine, Department of Molecular Microbiology, St. Louis, Missouri, United States of America
| | - Alexander Idnurm
- University of Missouri-Kansas City, School of Biological Sciences, Division of Cell Biology and Biophysics, Kansas City, Missouri, United States of America
| | - Jason E. Stajich
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
- University of California, Department of Plant Pathology & Microbiology, Riverside, California, United States of America
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, Vancouver, British Columbia, Canada
| | - Kaustuv Sanyal
- Jawaharlal Nehru Centre for Advanced Scientific Research, Molecular Biology and Genetics Unit, Bangalore, India
| | - Joseph Heitman
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
- * E-mail: (GJ); (JH); (CAC); (FSD)
| | - James A. Fraser
- University of Queensland, School of Chemistry and Molecular Biosciences, Brisbane, Queensland, Australia
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- * E-mail: (GJ); (JH); (CAC); (FSD)
| | - Fred S. Dietrich
- Duke University Medical Center, Department of Molecular Genetics and Microbiology, Durham, North Carolina, United States of America
- * E-mail: (GJ); (JH); (CAC); (FSD)
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Thakur J, Sanyal K. Efficient neocentromere formation is suppressed by gene conversion to maintain centromere function at native physical chromosomal loci in Candida albicans. Genome Res 2013; 23:638-52. [PMID: 23439889 PMCID: PMC3613581 DOI: 10.1101/gr.141614.112] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
CENPA/Cse4 assembles centromeric chromatin on diverse DNA. CENPA chromatin is epigenetically propagated on unique and different centromere DNA sequences in a pathogenic yeast Candida albicans. Formation of neocentromeres on DNA, nonhomologous to native centromeres, indicates a role of non-DNA sequence determinants in CENPA deposition. Neocentromeres have been shown to form at multiple loci in C. albicans when a native centromere was deleted. However, the process of site selection for CENPA deposition on native or neocentromeres in the absence of defined DNA sequences remains elusive. By systematic deletion of CENPA chromatin-containing regions of variable length of different chromosomes, followed by mapping of neocentromere loci in C. albicans and its related species Candida dubliniensis, which share similar centromere properties, we demonstrate that the chromosomal location is an evolutionarily conserved primary determinant of CENPA deposition. Neocentromeres on the altered chromosome are always formed close to the site which was once occupied by the native centromere. Interestingly, repositioning of CENPA chromatin from the neocentromere to the native centromere occurs by gene conversion in C. albicans.
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Affiliation(s)
- Jitendra Thakur
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India
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The genomes of the fungal plant pathogens Cladosporium fulvum and Dothistroma septosporum reveal adaptation to different hosts and lifestyles but also signatures of common ancestry. PLoS Genet 2012; 8:e1003088. [PMID: 23209441 PMCID: PMC3510045 DOI: 10.1371/journal.pgen.1003088] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 09/19/2012] [Indexed: 01/07/2023] Open
Abstract
We sequenced and compared the genomes of the Dothideomycete fungal plant pathogens Cladosporium fulvum (Cfu) (syn. Passalora fulva) and Dothistroma septosporum (Dse) that are closely related phylogenetically, but have different lifestyles and hosts. Although both fungi grow extracellularly in close contact with host mesophyll cells, Cfu is a biotroph infecting tomato, while Dse is a hemibiotroph infecting pine. The genomes of these fungi have a similar set of genes (70% of gene content in both genomes are homologs), but differ significantly in size (Cfu >61.1-Mb; Dse 31.2-Mb), which is mainly due to the difference in repeat content (47.2% in Cfu versus 3.2% in Dse). Recent adaptation to different lifestyles and hosts is suggested by diverged sets of genes. Cfu contains an α-tomatinase gene that we predict might be required for detoxification of tomatine, while this gene is absent in Dse. Many genes encoding secreted proteins are unique to each species and the repeat-rich areas in Cfu are enriched for these species-specific genes. In contrast, conserved genes suggest common host ancestry. Homologs of Cfu effector genes, including Ecp2 and Avr4, are present in Dse and induce a Cf-Ecp2- and Cf-4-mediated hypersensitive response, respectively. Strikingly, genes involved in production of the toxin dothistromin, a likely virulence factor for Dse, are conserved in Cfu, but their expression differs markedly with essentially no expression by Cfu in planta. Likewise, Cfu has a carbohydrate-degrading enzyme catalog that is more similar to that of necrotrophs or hemibiotrophs and a larger pectinolytic gene arsenal than Dse, but many of these genes are not expressed in planta or are pseudogenized. Overall, comparison of their genomes suggests that these closely related plant pathogens had a common ancestral host but since adapted to different hosts and lifestyles by a combination of differentiated gene content, pseudogenization, and gene regulation.
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Roy B, Varshney N, Yadav V, Sanyal K. The process of kinetochore assembly in yeasts. FEMS Microbiol Lett 2012; 338:107-17. [PMID: 23039831 DOI: 10.1111/1574-6968.12019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Revised: 09/29/2012] [Accepted: 10/01/2012] [Indexed: 12/14/2022] Open
Abstract
High fidelity chromosome segregation is essential for efficient transfer of the genetic material from the mother to daughter cells. The kinetochore (KT), which connects the centromere DNA to the spindle apparatus, plays a pivotal role in this process. In spite of considerable divergence in the centromere DNA sequence, basic architecture of a KT is evolutionarily conserved from yeast to humans. However, the identification of a large number of KT proteins paved the way of understanding conserved and diverged regulatory steps that lead to the formation of a multiprotein KT super-complex on the centromere DNA in different organisms. Because it is a daunting task to summarize the entire spectrum of information in a minireview, we focus here on the recent understanding in the process of KT assembly in three yeasts: Saccharomyces cerevisiae, Schizosaccharomyces pombe and Candida albicans. Studies in these unicellular organisms suggest that although the basic process of KT assembly remains the same, the dependence of a conserved protein for its KT localization may vary in these organisms.
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Affiliation(s)
- Babhrubahan Roy
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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28
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Affiliation(s)
- Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology & Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India.
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