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Carrère S, Routaboul JM, Savourat P, Bellenot C, López H, Sahoo A, Quiroz Monnens T, Ricou A, Camilleri C, Declerck N, Laufs P, Mercier R, Noël LD. A fully sequenced collection of homozygous EMS mutants for forward and reverse genetic screens in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 39073886 DOI: 10.1111/tpj.16954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 07/13/2024] [Indexed: 07/31/2024]
Abstract
Genetic screens are powerful tools for biological research and are one of the reasons for the success of the thale cress Arabidopsis thaliana as a research model. Here, we describe the whole-genome sequencing of 871 Arabidopsis lines from the Homozygous EMS Mutant (HEM) collection as a novel resource for forward and reverse genetics. With an average 576 high-confidence mutations per HEM line, over three independent mutations altering protein sequences are found on average per gene in the collection. Pilot reverse genetics experiments on reproductive, developmental, immune and physiological traits confirmed the efficacy of the tool for identifying both null, knockdown and gain-of-function alleles. The possibility of conducting subtle repeated phenotyping and the immediate availability of the mutations will empower forward genetic approaches. The sequence resource is searchable with the ATHEM web interface (https://lipm-browsers.toulouse.inra.fr/pub/ATHEM/), and the biological material is distributed by the Versailles Arabidopsis Stock Center.
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Affiliation(s)
- Sébastien Carrère
- LIPME, Université de Toulouse, INRAE/CNRS UMR 0441/2598, Castanet-Tolosan, France
| | - Jean-Marc Routaboul
- LIPME, Université de Toulouse, INRAE/CNRS UMR 0441/2598, Castanet-Tolosan, France
| | - Pauline Savourat
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000, Versailles, France
| | - Caroline Bellenot
- LIPME, Université de Toulouse, INRAE/CNRS UMR 0441/2598, Castanet-Tolosan, France
| | - Hernán López
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany
| | - Amruta Sahoo
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany
| | | | - Anthony Ricou
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000, Versailles, France
| | - Christine Camilleri
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000, Versailles, France
| | - Nathalie Declerck
- CBS, Université Montpellier, CNRS/INSERM, UMR5048/1054, Montpellier, France
| | - Patrick Laufs
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000, Versailles, France
| | - Raphaël Mercier
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany
| | - Laurent D Noël
- LIPME, Université de Toulouse, INRAE/CNRS UMR 0441/2598, Castanet-Tolosan, France
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2
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Capilla-Pérez L, Solier V, Gilbault E, Lian Q, Goel M, Huettel B, Keurentjes JJB, Loudet O, Mercier R. Enhanced recombination empowers the detection and mapping of Quantitative Trait Loci. Commun Biol 2024; 7:829. [PMID: 38977904 PMCID: PMC11231358 DOI: 10.1038/s42003-024-06530-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 07/02/2024] [Indexed: 07/10/2024] Open
Abstract
Modern plant breeding, such as genomic selection and gene editing, is based on the knowledge of the genetic architecture of desired traits. Quantitative trait loci (QTL) analysis, which combines high throughput phenotyping and genotyping of segregating populations, is a powerful tool to identify these genetic determinants and to decipher the underlying mechanisms. However, meiotic recombination, which shuffles genetic information between generations, is limited: Typically only one to two exchange points, called crossovers, occur between a pair of homologous chromosomes. Here we test the effect on QTL analysis of boosting recombination, by mutating the anti-crossover factors RECQ4 and FIGL1 in Arabidopsis thaliana full hybrids and lines in which a single chromosome is hybrid. We show that increasing recombination ~6-fold empowers the detection and resolution of QTLs, reaching the gene scale with only a few hundred plants. Further, enhanced recombination unmasks some secondary QTLs undetected under normal recombination. These results show the benefits of enhanced recombination to decipher the genetic bases of traits.
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Affiliation(s)
- Laia Capilla-Pérez
- Max Planck Institute for Plant Breeding Research, MPIPZ, Department of Chromosome Biology, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Victor Solier
- Max Planck Institute for Plant Breeding Research, MPIPZ, Department of Chromosome Biology, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Elodie Gilbault
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Qichao Lian
- Max Planck Institute for Plant Breeding Research, MPIPZ, Department of Chromosome Biology, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Manish Goel
- Max Planck Institute for Plant Breeding Research, MPIPZ, Department of Chromosome Biology, Carl-von-Linné Weg 10, 50829, Cologne, Germany
- Ludwig-Maximilians-Universität München, Fakultät für Biologie, Biozentrum Martinsried, 82152, Planegg-Martinsried, Germany
| | - Bruno Huettel
- Max Planck Institute for Plant Breeding Research, MPIPZ, Genome Center, Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Joost J B Keurentjes
- Laboratory of Genetics, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Olivier Loudet
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France.
| | - Raphael Mercier
- Max Planck Institute for Plant Breeding Research, MPIPZ, Department of Chromosome Biology, Carl-von-Linné Weg 10, 50829, Cologne, Germany.
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3
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Xu H, Zhang Y, Wang C, Fu Z, Lv J, Yang Y, Zhang Z, Qi Y, Meng K, Yuan J, Wang X. Research progress on the fanconi anemia signaling pathway in non-obstructive azoospermia. Front Endocrinol (Lausanne) 2024; 15:1393111. [PMID: 38846492 PMCID: PMC11153779 DOI: 10.3389/fendo.2024.1393111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/13/2024] [Indexed: 06/09/2024] Open
Abstract
Non-obstructive azoospermia (NOA) is a disease characterized by spermatogenesis failure and comprises phenotypes such as hypospermatogenesis, mature arrest, and Sertoli cell-only syndrome. Studies have shown that FA cross-linked anemia (FA) pathway is closely related to the occurrence of NOA. There are FA gene mutations in male NOA patients, which cause significant damage to male germ cells. The FA pathway is activated in the presence of DNA interstrand cross-links; the key step in activating this pathway is the mono-ubiquitination of the FANCD2-FANCI complex, and the activation of the FA pathway can repair DNA damage such as DNA double-strand breaks. Therefore, we believe that the FA pathway affects germ cells during DNA damage repair, resulting in minimal or even disappearance of mature sperm in males. This review summarizes the regulatory mechanisms of FA-related genes in male azoospermia, with the aim of providing a theoretical reference for clinical research and exploration of related genes.
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Affiliation(s)
- Haohui Xu
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Yixin Zhang
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Caiqin Wang
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Zhuoyan Fu
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Clinical Medicine, Jining Medical University, Jining, China
| | - Jing Lv
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Clinical Medicine, Jining Medical University, Jining, China
| | - Yufang Yang
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Mental Health, Jining Medical University, Jining, China
| | - Zihan Zhang
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Yuanmin Qi
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
- College of Clinical Medicine, Jining Medical University, Jining, China
| | - Kai Meng
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
| | - Jinxiang Yuan
- Lin He’s Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
| | - Xiaomei Wang
- College of Basic Medicine, Jining Medical University, Jining, China
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4
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Barua D, Płecha M, Muszewska A. A minimal Fanconi Anemia complex in early diverging fungi. Sci Rep 2024; 14:9922. [PMID: 38688950 PMCID: PMC11061109 DOI: 10.1038/s41598-024-60318-w] [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: 01/02/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024] Open
Abstract
Fanconi Anemia (FA) pathway resolves DNA interstrand cross links (ICL). The FA pathway was initially recognized in vertebrates, but was later confirmed in other animals and speculated in fungi. FA proteins FANCM, FANCL and FANCJ are present in Saccharomyces cerevisiae but, their mechanism of interaction to resolve ICL is still unclear. Unlike Dikarya, early diverging fungi (EDF) possess more traits shared with animals. We traced the evolutionary history of the FA pathway across Opisthokonta. We scanned complete proteomes for FA-related homologs to establish their taxonomic distribution and analyzed their phylogenetic trees. We checked transcription profiles of FA genes to test if they respond to environmental conditions and their genomic localizations for potential co-localization. We identified fungal homologs of the activation and ID complexes, 5 out of 8 core proteins, all of the endonucleases, and deubiquitination proteins. All fungi lack FANCC, FANCF and FANCG proteins responsible for post-replication repair and chromosome stability in animals. The observed taxonomic distribution can be attributed to a gradual degradation of the FA pathway from EDF to Dikarya. One of the key differences is that EDF have the ID complex recruiting endonucleases to the site of ICL. Moreover, 21 out of 32 identified FA genes are upregulated in response to different growth conditions. Several FA genes are co-localized in fungal genomes which also could facilitate co-expression. Our results indicate that a minimal FA pathway might still be functional in Mucoromycota with a gradual loss of components in Dikarya ancestors.
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Affiliation(s)
- Drishtee Barua
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106, Warsaw, Poland
| | - Magdalena Płecha
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106, Warsaw, Poland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106, Warsaw, Poland.
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Abstract
The raison d'être of meiosis is shuffling of genetic information via Mendelian segregation and, within individual chromosomes, by DNA crossing-over. These outcomes are enabled by a complex cellular program in which interactions between homologous chromosomes play a central role. We first provide a background regarding the basic principles of this program. We then summarize the current understanding of the DNA events of recombination and of three processes that involve whole chromosomes: homolog pairing, crossover interference, and chiasma maturation. All of these processes are implemented by direct physical interaction of recombination complexes with underlying chromosome structures. Finally, we present convergent lines of evidence that the meiotic program may have evolved by coupling of this interaction to late-stage mitotic chromosome morphogenesis.
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Affiliation(s)
- Denise Zickler
- Institute for Integrative Biology of the Cell (I2BC), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA;
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6
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Zhao J, Zhang Y, Li W, Yao M, Liu C, Zhang Z, Wang C, Wang X, Meng K. Research progress of the Fanconi anemia pathway and premature ovarian insufficiency†. Biol Reprod 2023; 109:570-585. [PMID: 37669135 DOI: 10.1093/biolre/ioad110] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 08/25/2023] [Accepted: 09/02/2023] [Indexed: 09/07/2023] Open
Abstract
The Fanconi anemia pathway is a key pathway involved in the repair of deoxyribonucleic acidinterstrand crosslinking damage, which chiefly includes the following four modules: lesion recognition, Fanconi anemia core complex recruitment, FANCD2-FANCI complex monoubiquitination, and downstream events (nucleolytic incision, translesion synthesis, and homologous recombination). Mutations or deletions of multiple Fanconi anemia genes in this pathway can damage the interstrand crosslinking repair pathway and disrupt primordial germ cell development and oocyte meiosis, thereby leading to abnormal follicular development. Premature ovarian insufficiency is a gynecological clinical syndrome characterized by amenorrhea and decreased fertility due to decreased oocyte pool, accelerated follicle atresia, and loss of ovarian function in women <40 years old. Furthermore, in recent years, several studies have detected mutations in the Fanconi anemia gene in patients with premature ovarian insufficiency. In addition, some patients with Fanconi anemia exhibit symptoms of premature ovarian insufficiency and infertility. The Fanconi anemia pathway and premature ovarian insufficiency are closely associated.
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Affiliation(s)
- Jingyu Zhao
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Yixin Zhang
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Wenbo Li
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Mengmeng Yao
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Chuqi Liu
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Zihan Zhang
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Caiqin Wang
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- College of Second Clinical Medical, Jining Medical University, Jining, China
| | - Xiaomei Wang
- College of Basic Medicine, Jining Medical University, Jining, China
| | - Kai Meng
- Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining Medical University, Jining, China
- Lin He's Academician Workstation of New Medicine and Clinical Translation, Jining Medical University, Jining, China
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7
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Tsui V, Lyu R, Novakovic S, Stringer JM, Dunleavy JE, Granger E, Semple T, Leichter A, Martelotto LG, Merriner DJ, Liu R, McNeill L, Zerafa N, Hoffmann ER, O’Bryan MK, Hutt K, Deans AJ, Heierhorst J, McCarthy DJ, Crismani W. Fancm has dual roles in the limiting of meiotic crossovers and germ cell maintenance in mammals. CELL GENOMICS 2023; 3:100349. [PMID: 37601968 PMCID: PMC10435384 DOI: 10.1016/j.xgen.2023.100349] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 03/30/2023] [Accepted: 06/02/2023] [Indexed: 08/22/2023]
Abstract
Meiotic crossovers are required for accurate chromosome segregation and producing new allelic combinations. Meiotic crossover numbers are tightly regulated within a narrow range, despite an excess of initiating DNA double-strand breaks. Here, we reveal the tumor suppressor FANCM as a meiotic anti-crossover factor in mammals. We use unique large-scale crossover analyses with both single-gamete sequencing and pedigree-based bulk-sequencing datasets to identify a genome-wide increase in crossover frequencies in Fancm-deficient mice. Gametogenesis is heavily perturbed in Fancm loss-of-function mice, which is consistent with the reproductive defects reported in humans with biallelic FANCM mutations. A portion of the gametogenesis defects can be attributed to the cGAS-STING pathway after birth. Despite the gametogenesis phenotypes in Fancm mutants, both sexes are capable of producing offspring. We propose that the anti-crossover function and role in gametogenesis of Fancm are separable and will inform diagnostic pathways for human genomic instability disorders.
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Affiliation(s)
- Vanessa Tsui
- DNA Repair and Recombination Laboratory, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
- The Faculty of Medicine, Dentistry and Health Science, The University of Melbourne, Parkville, VIC, Australia
| | - Ruqian Lyu
- Bioinformatics and Cellular Genomics, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
- Melbourne Integrative Genomics, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Stevan Novakovic
- DNA Repair and Recombination Laboratory, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
| | - Jessica M. Stringer
- Ovarian Biology Laboratory, Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Jessica E.M. Dunleavy
- Male Infertility and Germ Cell Biology Group, School of BioSciences and the Bio21 Institute, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Elissah Granger
- DNA Repair and Recombination Laboratory, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
| | - Tim Semple
- Single Cell Innovation Laboratory, Centre for Cancer Research, University of Melbourne, Parkville, VIC, Australia
| | - Anna Leichter
- Single Cell Innovation Laboratory, Centre for Cancer Research, University of Melbourne, Parkville, VIC, Australia
| | - Luciano G. Martelotto
- Single Cell Innovation Laboratory, Centre for Cancer Research, University of Melbourne, Parkville, VIC, Australia
| | - D. Jo Merriner
- Male Infertility and Germ Cell Biology Group, School of BioSciences and the Bio21 Institute, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Ruijie Liu
- Bioinformatics and Cellular Genomics, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
- Melbourne Integrative Genomics, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Lucy McNeill
- DNA Repair and Recombination Laboratory, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
| | - Nadeen Zerafa
- Ovarian Biology Laboratory, Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Eva R. Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Moira K. O’Bryan
- Male Infertility and Germ Cell Biology Group, School of BioSciences and the Bio21 Institute, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Karla Hutt
- Ovarian Biology Laboratory, Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Andrew J. Deans
- The Faculty of Medicine, Dentistry and Health Science, The University of Melbourne, Parkville, VIC, Australia
- Genome Stability Unit, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
| | - Jörg Heierhorst
- The Faculty of Medicine, Dentistry and Health Science, The University of Melbourne, Parkville, VIC, Australia
- Molecular Genetics Unit, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
| | - Davis J. McCarthy
- Bioinformatics and Cellular Genomics, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
- Melbourne Integrative Genomics, Faculty of Science, The University of Melbourne, Parkville, VIC, Australia
| | - Wayne Crismani
- DNA Repair and Recombination Laboratory, St Vincent’s Institute of Medical Research, Fitzroy, VIC, Australia
- The Faculty of Medicine, Dentistry and Health Science, The University of Melbourne, Parkville, VIC, Australia
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Rafiei N, Ronceret A. Crossover interference mechanism: New lessons from plants. Front Cell Dev Biol 2023; 11:1156766. [PMID: 37274744 PMCID: PMC10236007 DOI: 10.3389/fcell.2023.1156766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/17/2023] [Indexed: 06/06/2023] Open
Abstract
Plants are the source of our understanding of several fundamental biological principles. It is well known that Gregor Mendel discovered the laws of Genetics in peas and that maize was used for the discovery of transposons by Barbara McClintock. Plant models are still useful for the understanding of general key biological concepts. In this article, we will focus on discussing the recent plant studies that have shed new light on the mysterious mechanisms of meiotic crossover (CO) interference, heterochiasmy, obligatory CO, and CO homeostasis. Obligatory CO is necessary for the equilibrated segregation of homologous chromosomes during meiosis. The tight control of the different male and female CO rates (heterochiasmy) enables both the maximization and minimization of genome shuffling. An integrative model can now predict these observed aspects of CO patterning in plants. The mechanism proposed considers the Synaptonemal Complex as a canalizing structure that allows the diffusion of a class I CO limiting factor linearly on synapsed bivalents. The coarsening of this limiting factor along the SC explains the interfering spacing between COs. The model explains the observed coordinated processes between synapsis, CO interference, CO insurance, and CO homeostasis. It also easily explains heterochiasmy just considering the different male and female SC lengths. This mechanism is expected to be conserved in other species.
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