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Descorps-Declère S, Richard GF. Megasatellite formation and evolution in vertebrate genes. Cell Rep 2022; 40:111347. [PMID: 36103826 DOI: 10.1016/j.celrep.2022.111347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 04/28/2022] [Accepted: 08/23/2022] [Indexed: 11/03/2022] Open
Abstract
Since formation of the first proto-eukaryotes, gene repertoire and genome complexity have significantly increased. Among genetic elements responsible for this increase are tandem repeats. Here we describe a genome-wide analysis of large tandem repeats, called megasatellites, in 58 vertebrate genomes. Two bursts occurred, one after the radiation between Agnatha and Gnathostomata fishes and the second one in therian mammals. Megasatellites are enriched in subtelomeric regions and frequently encoded in genes involved in transcription regulation, intracellular trafficking, and cell membrane metabolism, reminiscent of what is observed in fungus genomes. The presence of many introns within young megasatellites suggests that an exon-intron DNA segment is first duplicated and amplified before accumulation of mutations in intronic parts partially erases the megasatellite in such a way that it becomes detectable only in exons. Our results suggest that megasatellite formation and evolution is a dynamic and still ongoing process in vertebrate genomes.
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Affiliation(s)
- Stéphane Descorps-Declère
- Institut Pasteur, Université Paris Cité, Bioinformatics and Biostatistics Hub, 25 rue du Dr Roux, 75015 Paris, France.
| | - Guy-Franck Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Natural & Synthetic Genome Instabilities, 25 rue du Dr Roux, 75015 Paris, France.
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2
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Saguez C, Viterbo D, Descorps-Declère S, Cormack BP, Dujon B, Richard GF. Functional variability in adhesion and flocculation of yeast megasatellite genes. Genetics 2022; 221:iyac042. [PMID: 35274698 PMCID: PMC9071537 DOI: 10.1093/genetics/iyac042] [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: 01/19/2022] [Accepted: 03/07/2022] [Indexed: 11/14/2022] Open
Abstract
Megasatellites are large tandem repeats found in all fungal genomes but especially abundant in the opportunistic pathogen Candida glabrata. They are encoded in genes involved in cell-cell interactions, either between yeasts or between yeast and human cells. In the present work, we have been using an iterative genetic system to delete several Candida glabrata megasatellite-containing genes and found that 2 of them were positively involved in adhesion to epithelial cells, whereas 3 genes negatively controlled adhesion. Two of the latter, CAGL0B05061g or CAGL0A04851g, were also negative regulators of yeast-to-yeast adhesion, making them central players in controlling Candida glabrata adherence properties. Using a series of synthetic Saccharomyces cerevisiae strains in which the FLO1 megasatellite was replaced by other tandem repeats of similar length but different sequences, we showed that the capacity of a strain to flocculate in liquid culture was unrelated to its capacity to adhere to epithelial cells or to invade agar. Finally, to understand how megasatellites were initially created and subsequently expanded, an experimental evolution system was set up, in which modified yeast strains containing different megasatellite seeds were grown in bioreactors for more than 200 generations and selected for their ability to sediment at the bottom of the culture tube. Several flocculation-positive mutants were isolated. Functionally relevant mutations included general transcription factors as well as a 230-kbp segmental duplication.
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Affiliation(s)
- Cyril Saguez
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
- Present address: Abolis Biotechnologies, 5 Rue Henri Desbruères, Evry 91030, France
| | - David Viterbo
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
| | - Stéphane Descorps-Declère
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
- Institut Pasteur, Bioinformatics and Biostatistics Hub, Department of Computational Biology, Paris F-75015, France
| | - Brendan P Cormack
- Department of Molecular Biology & Genetics, Johns Hopkins University, Baltimore, Maryland 21287, USA
| | - Bernard Dujon
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
| | - Guy-Franck Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
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3
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Capece A, Romaniello R, Siesto G, Romano P. Diversity of Saccharomyces cerevisiae yeasts associated to spontaneously fermenting grapes from an Italian “heroic vine-growing area”. Food Microbiol 2012; 31:159-66. [DOI: 10.1016/j.fm.2012.03.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/02/2012] [Accepted: 03/19/2012] [Indexed: 11/30/2022]
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4
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Barman HK, Patra SK, Das V, Mohapatra SD, Jayasankar P, Mohapatra C, Mohanta R, Panda RP, Rath SN. Identification and characterization of differentially expressed transcripts in the gills of freshwater prawn (Macrobrachium rosenbergii) under salt stress. ScientificWorldJournal 2012; 2012:149361. [PMID: 22619594 PMCID: PMC3349099 DOI: 10.1100/2012/149361] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 11/15/2011] [Indexed: 11/17/2022] Open
Abstract
The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important species. It is a euryhaline shrimp, surviving in wide-range salinity conditions. A change in gene expression has been suggested as an important component for stress management. To better understand the osmoregulatory mechanisms mediated by the gill, a subtractive and suppressive hybridization (SSH) tool was used to identify expressed transcripts linked to adaptations in saline water. A total of 117 transcripts represented potentially expressed under salinity conditions. BLAST analysis identified 22% as known genes, 9% as uncharacterized showing homologous to unannotated ESTs, and 69% as unknown sequences. All the identified known genes representing broad spectrum of biological pathways were particularly linked to stress tolerance including salinity tolerance. Expression analysis of 10 known genes and 7 unknown/uncharacterized genes suggested their upregulation in the gills of prawn exposed to saline water as compared to control indicating that these are likely to be associated with salinity acclimation. Rapid amplification of cDNA ends (RACE) was used for obtaining full-length cDNA of MRSW-40 clone that was highly upregulated during salt exposure. The sequenced ESTs presented here will have potential implications for future understanding about salinity acclimation and/or tolerance of the prawn.
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Affiliation(s)
- Hirak Kumar Barman
- Fish Genetics and Biotechnology Division, Central Institute of Freshwater Aquaculture, Indian Council of Agricultural Research, Kausalyaganga, Bhubaneswar, Odisha 751002, India.
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5
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Cheng J, Xue H, Zhao X. Variation of serine-aspartate repeats in membrane proteins possibly contributes to staphylococcal microevolution. PLoS One 2012; 7:e34756. [PMID: 22509353 PMCID: PMC3324548 DOI: 10.1371/journal.pone.0034756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Accepted: 03/05/2012] [Indexed: 11/18/2022] Open
Abstract
Tandem repeats (either as microsatellites or minisatellites) in eukaryotic and prokaryotic organisms are mutation-prone DNA. While minisatellites in prokaryotic genomes are underrepresented, the cell surface adhesins of bacteria often contain the minisatellite SD repeats, encoding the amino acid pair of serine-asparatate, especially in Staphylococcal strains. However, their relationship to biological functions is still elusive. In this study, effort was made to uncover the copy number variations of SD repeats by bioinformatic analysis and to detect changes in SD repeats during a plasmid-based assay, as a first step to understand its biological functions. The SD repeats were found to be mainly present in the cell surface proteins. The SD repeats were genetically unstable and polymorphic in terms of copy numbers and sequence compositions. Unlike SNPs, the change of its copy number was reversible, without frame shifting. More significantly, a rearrangement hot spot, the ATTC/AGRT site, was found to be mainly responsible for the instability and reversibility of SD repeats. These characteristics of SD repeats may facilitate bacteria to respond to environmental changes, with low cost, low risk and high efficiency.
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Affiliation(s)
- Jing Cheng
- Department of Animal Science, McGill University, Montreal, Quebec, Canada
| | - Huping Xue
- Department of Animal Science, McGill University, Montreal, Quebec, Canada
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Xin Zhao
- Department of Animal Science, McGill University, Montreal, Quebec, Canada
- * E-mail:
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6
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Tan JC, Tan A, Checkley L, Honsa CM, Ferdig MT. Variable numbers of tandem repeats in Plasmodium falciparum genes. J Mol Evol 2010; 71:268-78. [PMID: 20730584 DOI: 10.1007/s00239-010-9381-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 08/09/2010] [Indexed: 11/29/2022]
Abstract
Genome variation studies in Plasmodium falciparum have focused on SNPs and, more recently, large-scale copy number polymorphisms and ectopic rearrangements. Here, we examine another source of variation: variable number tandem repeats (VNTRs). Interspersed low complexity features, including the well-studied P. falciparum microsatellite sequences, are commonly classified as VNTRs; however, this study is focused on longer coding VNTR polymorphisms, a small class of copy number variations. Selection against frameshift mutation is a main constraint on tandem repeats (TRs) in coding regions, while limited propagation of TRs longer than 975 nt total length is a minor restriction in coding regions. Comparative analysis of three P. falciparum genomes reveals that more than 9% of all P. falciparum ORFs harbor VNTRs, much more than has been reported for any other species. Moreover, genotyping of VNTR loci in a drug-selected line, progeny of a genetic cross, and 334 field isolates demonstrates broad variability in these sequences. Functional enrichment analysis of ORFs harboring VNTRs identifies stress and DNA damage responses along with chromatin modification activities, suggesting an influence on genome mutability and functional variation. Analysis of the repeat units and their flanking regions in both P. falciparum and Plasmodium reichenowi sequences implicates a replication slippage mechanism in the generation of TRs from an initially unrepeated sequence. VNTRs can contribute to rapid adaptation by localized sequence duplication. They also can confound SNP-typing microarrays or mapping short-sequence reads and therefore must be accounted for in such analyses.
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Affiliation(s)
- John C Tan
- The Eck Institute for Global Health, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN, 46556, USA.
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7
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Abstract
Megasatellites are a new family of long tandem repeats, recently discovered in the yeast Candida glabrata. Compared to shorter tandem repeats, such as minisatellites, megasatellite motifs range in size from 135 to more than 300 bp, and allow calculation of evolutionary distances between individual motifs. Using divergence based on nucleotide substitutions among similar motifs, we determined the smallest distance between two motifs, allowing their subsequent clustering. Motifs belonging to the same cluster are recurrently found in different megasatellites located on different chromosomes, showing transfer of genetic information between megasatellites. In comparison, evolution of the few similar tandem repeats in Saccharomyces cerevisiae FLO genes mainly involves subtelomeric homologous recombination. We estimated selective constraints acting on megasatellite motifs and their host genes, and found that motifs are under strong purifying selection. Surprisingly, motifs inserted within pseudogenes are also under purifying selection, whereas the pseudogenes themselves evolve neutrally. We propose that megasatellite motifs propagate by a combination of three different molecular mechanisms: (i) gene duplication, (ii) ectopic homologous recombination and (iii) transfer of motifs from one megasatellite to another one. These mechanisms actively cooperate to create new megasatellites, that may play an important role in the adaptation of Candida glabrata to its human host.
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Affiliation(s)
- Thomas Rolland
- Institut Pasteur, Unité de Génétique Moléculaire des Levures, Department Genomes and Genetics, Paris, France
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8
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Thierry A, Dujon B, Richard GF. Megasatellites: a new class of large tandem repeats discovered in the pathogenic yeast Candida glabrata. Cell Mol Life Sci 2010; 67:671-6. [PMID: 19946728 PMCID: PMC11115930 DOI: 10.1007/s00018-009-0216-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 11/09/2009] [Accepted: 11/10/2009] [Indexed: 11/29/2022]
Abstract
Megasatellites are DNA tandem arrays made of large motifs; they were discovered in the yeast Candida glabrata. They are widespread in this species (40 copies) but are not found in any other hemiascomycete so far, raising the intriguing question of their origin. They are found mainly in genes encoding cell wall products, suggesting that megasatellites were selected for a function linked to cell-cell adhesion or to pathogenicity. Their putative role in promoting genome rearrangements by interfering with DNA replication will also be discussed.
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Affiliation(s)
- Agnès Thierry
- Unité de Génétique Moléculaire des Levures, Institut Pasteur, CNRS URA2171, Université Pierre et Marie Curie UFR 927, 25 rue du Dr Roux, 75015 Paris, France
| | - Bernard Dujon
- Unité de Génétique Moléculaire des Levures, Institut Pasteur, CNRS URA2171, Université Pierre et Marie Curie UFR 927, 25 rue du Dr Roux, 75015 Paris, France
| | - Guy-Franck Richard
- Unité de Génétique Moléculaire des Levures, Institut Pasteur, CNRS URA2171, Université Pierre et Marie Curie UFR 927, 25 rue du Dr Roux, 75015 Paris, France
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9
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Zara G, Zara S, Pinna C, Marceddu S, Budroni M. FLO11 gene length and transcriptional level affect biofilm-forming ability of wild flor strains of Saccharomyces cerevisiae. MICROBIOLOGY-SGM 2009; 155:3838-3846. [PMID: 19729408 DOI: 10.1099/mic.0.028738-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In Saccharomyces cerevisiae, FLO11 encodes an adhesin that is associated with different phenotypes, such as adherence to solid surfaces, hydrophobicity, mat and air-liquid biofilm formation. In the present study, we analysed FLO11 allelic polymorphisms and FLO11-associated phenotypes of 20 flor strains. We identified 13 alleles of different lengths, varying from 3.0 to 6.1 kb, thus demonstrating that FLO11 is highly polymorphic. Two alleles of 3.1 and 5.0 kb were cloned into strain BY4742 to compare the FLO11-associated phenotypes in the same genetic background. We show that there is a significant correlation between biofilm-forming ability and FLO11 length both in different and in the same genetic backgrounds. Moreover, we propose a multiple regression model that allows prediction of air-liquid biofilm-forming ability on the basis of transcription levels and lengths of FLO11 alleles in a population of S. cerevisiae flor strains. Considering that transcriptional differences are only partially explained by the differences in the promoter sequences, our results are consistent with the hypothesis that FLO11 transcription levels are strongly influenced by genetic background and affect biofilm-forming ability.
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Affiliation(s)
- Giacomo Zara
- Dipartimento di Scienze Ambientali Agrarie e Biotecnologie Agro-alimentari (DISAABA), University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Severino Zara
- Dipartimento di Scienze Ambientali Agrarie e Biotecnologie Agro-alimentari (DISAABA), University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Claudia Pinna
- Dipartimento di Scienze Ambientali Agrarie e Biotecnologie Agro-alimentari (DISAABA), University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Salvatore Marceddu
- Istituto di Scienze delle Produzioni Alimentari (ISPA CNR Sassari), Via dei Mille 48, 07100 Sassari, Italy
| | - Marilena Budroni
- Dipartimento di Scienze Ambientali Agrarie e Biotecnologie Agro-alimentari (DISAABA), University of Sassari, Viale Italia 39, 07100 Sassari, Italy
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10
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Gibbons JG, Rokas A. Comparative and functional characterization of intragenic tandem repeats in 10 Aspergillus genomes. Mol Biol Evol 2008; 26:591-602. [PMID: 19056904 DOI: 10.1093/molbev/msn277] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Intragenic tandem repeats (ITRs) are consecutive repeats of three or more nucleotides found in coding regions. ITRs are the underlying cause of several human genetic diseases and have been associated with phenotypic variation, including pathogenesis, in several clades of the tree of life. We have examined the evolution and functional role of ITRs in 10 genomes spanning the fungal genus Aspergillus, a clade of relevance to medicine, agriculture, and industry. We identified several hundred ITRs in each of the species examined. ITR content varied extensively between species, with an average 79% of ITRs unique to a given species. For the fraction of conserved ITR regions, sequence comparisons within species and between close relatives revealed that they were highly variable. ITR-containing proteins were evolutionarily less conserved, compositionally distinct, and overrepresented for domains associated with cell-surface localization and function relative to the rest of the proteome. Furthermore, ITRs were preferentially found in proteins involved in transcription, cellular communication, and cell-type differentiation but were underrepresented in proteins involved in metabolism and energy. Importantly, although ITRs were evolutionarily labile, their functional associations appeared. To be remarkably conserved across eukaryotes. Fungal ITRs likely participate in a variety of developmental processes and cell-surface-associated functions, suggesting that their contribution to fungal lifestyle and evolution may be more general than previously assumed.
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Affiliation(s)
- John G Gibbons
- Department of Biological Sciences, Vanderbilt University, Nashville, USA
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11
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Richard GF, Kerrest A, Dujon B. Comparative genomics and molecular dynamics of DNA repeats in eukaryotes. Microbiol Mol Biol Rev 2008; 72:686-727. [PMID: 19052325 PMCID: PMC2593564 DOI: 10.1128/mmbr.00011-08] [Citation(s) in RCA: 335] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Repeated elements can be widely abundant in eukaryotic genomes, composing more than 50% of the human genome, for example. It is possible to classify repeated sequences into two large families, "tandem repeats" and "dispersed repeats." Each of these two families can be itself divided into subfamilies. Dispersed repeats contain transposons, tRNA genes, and gene paralogues, whereas tandem repeats contain gene tandems, ribosomal DNA repeat arrays, and satellite DNA, itself subdivided into satellites, minisatellites, and microsatellites. Remarkably, the molecular mechanisms that create and propagate dispersed and tandem repeats are specific to each class and usually do not overlap. In the present review, we have chosen in the first section to describe the nature and distribution of dispersed and tandem repeats in eukaryotic genomes in the light of complete (or nearly complete) available genome sequences. In the second part, we focus on the molecular mechanisms responsible for the fast evolution of two specific classes of tandem repeats: minisatellites and microsatellites. Given that a growing number of human neurological disorders involve the expansion of a particular class of microsatellites, called trinucleotide repeats, a large part of the recent experimental work on microsatellites has focused on these particular repeats, and thus we also review the current knowledge in this area. Finally, we propose a unified definition for mini- and microsatellites that takes into account their biological properties and try to point out new directions that should be explored in a near future on our road to understanding the genetics of repeated sequences.
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Affiliation(s)
- Guy-Franck Richard
- Institut Pasteur, Unité de Génétique Moléculaire des Levures, CNRS, URA2171, Université Pierre et Marie Curie, UFR927, 25 rue du Dr. Roux, F-75015, Paris, France.
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12
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Thierry A, Bouchier C, Dujon B, Richard GF. Megasatellites: a peculiar class of giant minisatellites in genes involved in cell adhesion and pathogenicity in Candida glabrata. Nucleic Acids Res 2008; 36:5970-82. [PMID: 18812401 PMCID: PMC2566889 DOI: 10.1093/nar/gkn594] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Minisatellites are DNA tandem repeats that are found in all sequenced genomes. In the yeast Saccharomyces cerevisiae, they are frequently encountered in genes encoding cell wall proteins. Minisatellites present in the completely sequenced genome of the pathogenic yeast Candida glabrata were similarly analyzed, and two new types of minisatellites were discovered: minisatellites that are composed of two different intermingled repeats (called compound minisatellites), and minisatellites containing unusually long repeated motifs (126–429 bp). These long repeat minisatellites may reach unusual length for such elements (up to 10 kb). Due to these peculiar properties, they have been named ‘megasatellites’. They are found essentially in genes involved in cell–cell adhesion, and could therefore be involved in the ability of this opportunistic pathogen to colonize the human host. In addition to megasatellites, found in large paralogous gene families, there are 93 minisatellites with simple shorter motifs, comparable to those found in S. cerevisiae. Most of the time, these minisatellites are not conserved between C. glabrata and S. cerevisiae, although their host genes are well conserved, raising the question of an active mechanism creating minisatellites de novo in hemiascomycetes.
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Affiliation(s)
- Agnès Thierry
- Institut Pasteur, Unité de Génétique Moléculaire des Levures, CNRS, URA2171, F-75015 Paris, France
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13
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Legendre M, Pochet N, Pak T, Verstrepen KJ. Sequence-based estimation of minisatellite and microsatellite repeat variability. Genome Res 2007; 17:1787-96. [PMID: 17978285 DOI: 10.1101/gr.6554007] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Variable tandem repeats are frequently used for genetic mapping, genotyping, and forensics studies. Moreover, variation in some repeats underlies rapidly evolving traits or certain diseases. However, mutation rates vary greatly from repeat to repeat, and as a consequence, not all tandem repeats are suitable genetic markers or interesting unstable genetic modules. We developed a model, "SERV," that predicts the variability of a broad range of tandem repeats in a wide range of organisms. The nonlinear model uses three basic characteristics of the repeat (number of repeated units, unit length, and purity) to produce a numeric "VARscore" that correlates with repeat variability. SERV was experimentally validated using a large set of different artificial repeats located in the Saccharomyces cerevisiae URA3 gene. Further in silico analysis shows that SERV outperforms existing models and accurately predicts repeat variability in bacteria and eukaryotes, including plants and humans. Using SERV, we demonstrate significant enrichment of variable repeats within human genes involved in transcriptional regulation, chromatin remodeling, morphogenesis, and neurogenesis. Moreover, SERV allows identification of known and candidate genes involved in repeat-based diseases. In addition, we demonstrate the use of SERV for the selection and comparison of suitable variable repeats for genotyping and forensic purposes. Our analysis indicates that tandem repeats used for genotyping should have a VARscore between 1 and 3. SERV is publicly available from http://hulsweb1.cgr.harvard.edu/SERV/.
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Affiliation(s)
- Matthieu Legendre
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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14
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Bowen S, Wheals AE. Ser/Thr-rich domains are associated with genetic variation and morphogenesis inSaccharomyces cerevisiae. Yeast 2006; 23:633-40. [PMID: 16823884 DOI: 10.1002/yea.1381] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Proteins containing regions of amino acid bias are often found in eukaryotes and are associated with particular functional groups. We have carried out a genomic analysis of yeast proteins containing regions with a significant bias of Ser and Thr residues. Our findings reveal that a high number are cell surface proteins or regulatory proteins involved in many aspects of cell differentiation. Furthermore, in Saccharomyces-related species, a highly significant correlation exists between the frequency of Ser-rich regions and DNA repeats, indicating that their generation may rely on similar factors. Cluster analysis shows that Ser/Thr-rich regions, located within the tandem repeats of cell surface proteins, are encoded to an increased frequency by UCU (Ser) and ACU/ACC (Thr), implying that mutational events that generate iterations could involve these codons. Replication slippage is proposed to be a contributing factor, as mounting evidence suggests that repeat generation in cell surface proteins can occur independently of meiosis. To reinforce this argument, we have discovered a premeiotic association between Mre11p, a nuclease involved in DNA repair, and ORFs encoding Ser/Thr-rich regions. Several macromolecules involved in the glycosylation and phosphorylation of proteins require Ser and Thr residues as binding sites. Ser/Thr-rich regions, through polymorphisms, are associated with the evolution of functional sites, particularly in providing motifs for glycosylation and phosphorylation. These results point to a Ser/Thr-biased somatic mutation mechanism that contributes to rapid evolution in yeast.
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Affiliation(s)
- Suzanne Bowen
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
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15
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Bowen S, Wheals AE. Evidence that Protein Length Expansion and Contraction Is Partly Due to Mutational Events in Premeiotic Cells. Mol Biol Evol 2006; 23:1339-40. [PMID: 16621914 DOI: 10.1093/molbev/msk024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Studies on the rate of evolution of proteins typically concentrate on rates of change of orthologous amino acids rather than on changes in size (i.e., generation of nonorthologous domains). Recent work has focused attention on Ser/Thr-rich regions in yeast as these tend to undergo size changes rapidly, with size polymorphisms commonly being found, especially in proteins with cell-surface localization. The underlying mechanism generating the indels is presently unclear though, due to a lack of correlation with the location of meiotic double-strand breaks, it has, by exclusion, been conjectured to be replication slippage. Here we provide new evidence to support this possibility. Notably, we show that Ser/Thr-rich repeat regions are more generally associated with the location of Mre11p in premeiotic cells. This is to be expected if the repeats were produced by mutational events in mitotic cells possibly through replication slippage.
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16
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Current awareness on yeast. Yeast 2005; 22:1249-56. [PMID: 16320446 DOI: 10.1002/yea.1170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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