1
|
Nikolić I, Milisavljević M, Timotijević G. Assessing Transcriptomic Responses to Oxidative Stress: Contrasting Wild-Type Arabidopsis Seedlings with dss1(I) and dss1(V) Gene Knockout Mutants. Int J Mol Sci 2024; 25:6291. [PMID: 38927997 PMCID: PMC11203560 DOI: 10.3390/ijms25126291] [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: 05/08/2024] [Revised: 05/24/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
Oxidative stress represents a critical facet of the array of abiotic stresses affecting crop growth and yield. In this paper, we investigated the potential differences in the functions of two highly homologous Arabidopsis DSS1 proteins in terms of maintaining genome integrity and response to oxidative stress. In the context of homologous recombination (HR), it was shown that overexpressing AtDSS1(I) using a functional complementation test increases the resistance of the Δdss1 mutant of Ustilago maydis to genotoxic agents. This indicates its conserved role in DNA repair via HR. To investigate the global transcriptome changes occurring in dss1 plant mutant lines, gene expression analysis was conducted using Illumina RNA sequencing technology. Individual RNA libraries were constructed from three total RNA samples isolated from dss1(I), dss1(V), and wild-type (WT) plants under hydrogen peroxide-induced stress. RNA-Seq data analysis and real-time PCR identification revealed major changes in gene expression between mutant lines and WT, while the dss1(I) and dss1(V) mutant lines exhibited analogous transcription profiles. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed significantly enriched metabolic pathways. Notably, genes associated with HR were upregulated in dss1 mutants compared to the WT. Otherwise, genes of the metabolic pathway responsible for the synthesis of secondary metabolites were downregulated in both dss1 mutant lines. These findings highlight the importance of understanding the molecular mechanisms of plant responses to oxidative stress.
Collapse
Affiliation(s)
| | | | - Gordana Timotijević
- Group for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (I.N.); (M.M.)
| |
Collapse
|
2
|
Ito M, Fujita Y, Shinohara A. Positive and negative regulators of RAD51/DMC1 in homologous recombination and DNA replication. DNA Repair (Amst) 2024; 134:103613. [PMID: 38142595 DOI: 10.1016/j.dnarep.2023.103613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/10/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023]
Abstract
RAD51 recombinase plays a central role in homologous recombination (HR) by forming a nucleoprotein filament on single-stranded DNA (ssDNA) to catalyze homology search and strand exchange between the ssDNA and a homologous double-stranded DNA (dsDNA). The catalytic activity of RAD51 assembled on ssDNA is critical for the DNA-homology-mediated repair of DNA double-strand breaks in somatic and meiotic cells and restarting stalled replication forks during DNA replication. The RAD51-ssDNA complex also plays a structural role in protecting the regressed/reversed replication fork. Two types of regulators control RAD51 filament formation, stability, and dynamics, namely positive regulators, including mediators, and negative regulators, so-called remodelers. The appropriate balance of action by the two regulators assures genome stability. This review describes the roles of positive and negative RAD51 regulators in HR and DNA replication and its meiosis-specific homolog DMC1 in meiotic recombination. We also provide future study directions for a comprehensive understanding of RAD51/DMC1-mediated regulation in maintaining and inheriting genome integrity.
Collapse
Affiliation(s)
- Masaru Ito
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Yurika Fujita
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| | - Akira Shinohara
- Institute for Protein Research, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan.
| |
Collapse
|
3
|
Ghouil R, Miron S, Sato K, Ristic D, van Rossum-Fikkert SE, Legrand P, Ouldali M, Winter JM, Ropars V, David G, Arteni AA, Wyman C, Knipscheer P, Kanaar R, Zelensky AN, Zinn-Justin S. BRCA2-HSF2BP oligomeric ring disassembly by BRME1 promotes homologous recombination. SCIENCE ADVANCES 2023; 9:eadi7352. [PMID: 37889963 PMCID: PMC10610910 DOI: 10.1126/sciadv.adi7352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023]
Abstract
In meiotic homologous recombination (HR), BRCA2 facilitates loading of the recombinases RAD51 and DMC1 at the sites of double-strand breaks (DSBs). The HSF2BP-BRME1 complex interacts with BRCA2. Its absence causes a severe reduction in recombinase loading at meiotic DSB. We previously showed that, in somatic cancer cells ectopically producing HSF2BP, DNA damage can trigger HSF2BP-dependent degradation of BRCA2, which prevents HR. Here, we report that, upon binding to BRCA2, HSF2BP forms octameric rings that are able to interlock into a large ring-shaped 24-mer. Addition of BRME1 leads to dissociation of both of these ring structures and cancels the disruptive effect of HSF2BP on cancer cell resistance to DNA damage. It also prevents BRCA2 degradation during interstrand DNA crosslink repair in Xenopus egg extracts. We propose that, during meiosis, the control of HSF2BPBRCA2 oligomerization by BRME1 ensures timely assembly of the ring complex that concentrates BRCA2 and controls its turnover, thus promoting HR.
Collapse
Affiliation(s)
- Rania Ghouil
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Simona Miron
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Koichi Sato
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Utrecht, Netherlands
| | - Dejan Ristic
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Sari E. van Rossum-Fikkert
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio group, L’Orme des Merisiers, Gif sur-Yvette, France
| | - Malika Ouldali
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | | | - Virginie Ropars
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Gabriel David
- Synchrotron SOLEIL, HelioBio group, L’Orme des Merisiers, Gif sur-Yvette, France
| | - Ana-Andreea Arteni
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Claire Wyman
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
- Department of Radiation Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Puck Knipscheer
- Oncode Institute, Hubrecht Institute–KNAW and University Medical Center Utrecht, Utrecht, Netherlands
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Alex N. Zelensky
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, Netherlands
| | - Sophie Zinn-Justin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| |
Collapse
|
4
|
Zhang T, Zhao SH, Wang Y, He Y. FIGL1 coordinates with dosage-sensitive BRCA2 in modulating meiotic recombination in maize. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2107-2121. [PMID: 37293848 DOI: 10.1111/jipb.13541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/01/2023] [Indexed: 06/10/2023]
Abstract
Meiotic crossover (CO) formation between homologous chromosomes ensures their subsequent proper segregation and generates genetic diversity among offspring. In maize, however, the mechanisms that modulate CO formation remain poorly characterized. Here, we found that both maize BREAST CANCER SUSCEPTIBILITY PROTEIN 2 (BRCA2) and AAA-ATPase FIDGETIN-LIKE-1 (FIGL1) act as positive factors of CO formation by controlling the assembly or/and stability of two conserved DNA recombinases RAD51 and DMC1 filaments. Our results revealed that ZmBRCA2 is not only involved in the repair of DNA double-stranded breaks (DSBs), but also regulates CO formation in a dosage-dependent manner. In addition, ZmFIGL1 interacts with RAD51 and DMC1, and Zmfigl1 mutants had a significantly reduced number of RAD51/DMC1 foci and COs. Further, simultaneous loss of ZmFIGL1 and ZmBRCA2 abolished RAD51/DMC1 foci and exacerbated meiotic defects compared with the single mutant Zmbrca2 or Zmfigl1. Together, our data demonstrate that ZmBRCA2 and ZmFIGL1 act coordinately to regulate the dynamics of RAD51/DMC1-dependent DSB repair to promote CO formation in maize. This conclusion is surprisingly different from the antagonistic roles of BRCA2 and FIGL1 in Arabidopsis, implying that, although key factors that control CO formation are evolutionarily conserved, specific characteristics have been adopted in diverse plant species.
Collapse
Affiliation(s)
- Ting Zhang
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Shuang-Hui Zhao
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Yan Wang
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| | - Yan He
- MOE Key Laboratory of Crop Heterosis and Utilization, National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
| |
Collapse
|
5
|
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.
Collapse
|
6
|
Emmenecker C, Mézard C, Kumar R. Repair of DNA double-strand breaks in plant meiosis: role of eukaryotic RecA recombinases and their modulators. PLANT REPRODUCTION 2023; 36:17-41. [PMID: 35641832 DOI: 10.1007/s00497-022-00443-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
Homologous recombination during meiosis is crucial for the DNA double-strand breaks (DSBs) repair that promotes the balanced segregation of homologous chromosomes and enhances genetic variation. In most eukaryotes, two recombinases RAD51 and DMC1 form nucleoprotein filaments on single-stranded DNA generated at DSB sites and play a central role in the meiotic DSB repair and genome stability. These nucleoprotein filaments perform homology search and DNA strand exchange to initiate repair using homologous template-directed sequences located elsewhere in the genome. Multiple factors can regulate the assembly, stability, and disassembly of RAD51 and DMC1 nucleoprotein filaments. In this review, we summarize the current understanding of the meiotic functions of RAD51 and DMC1 and the role of their positive and negative modulators. We discuss the current models and regulators of homology searches and strand exchange conserved during plant meiosis. Manipulation of these repair factors during plant meiosis also holds a great potential to accelerate plant breeding for crop improvements and productivity.
Collapse
Affiliation(s)
- Côme Emmenecker
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France
- University of Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Christine Mézard
- Institut Jean-Pierre Bourgin (IJPB), CNRS, Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
| | - Rajeev Kumar
- Institut Jean-Pierre Bourgin (IJPB), Université Paris-Saclay, INRAE, AgroParisTech, 78000, Versailles, France.
| |
Collapse
|
7
|
Nikolić I, Samardžić J, Stevanović S, Miljuš-Đukić J, Milisavljević M, Timotijević G. CRISPR/Cas9-Targeted Disruption of Two Highly Homologous Arabidopsis thaliana DSS1 Genes with Roles in Development and the Oxidative Stress Response. Int J Mol Sci 2023; 24:ijms24032442. [PMID: 36768765 PMCID: PMC9916663 DOI: 10.3390/ijms24032442] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/13/2023] [Accepted: 01/21/2023] [Indexed: 01/28/2023] Open
Abstract
Global climate change has a detrimental effect on plant growth and health, causing serious losses in agriculture. Investigation of the molecular mechanisms of plant responses to various environmental pressures and the generation of plants tolerant to abiotic stress are imperative to modern plant science. In this paper, we focus on the application of the well-established technology CRISPR/Cas9 genome editing to better understand the functioning of the intrinsically disordered protein DSS1 in plant response to oxidative stress. The Arabidopsis genome contains two highly homologous DSS1 genes, AtDSS1(I) and AtDSS1(V). This study was designed to identify the functional differences between AtDSS1s, focusing on their potential roles in oxidative stress. We generated single dss1(I) and dss1(V) mutant lines of both Arabidopsis DSS1 genes using CRISPR/Cas9 technology. The homozygous mutant lines with large indels (dss1(I)del25 and dss1(V)ins18) were phenotypically characterized during plant development and their sensitivity to oxidative stress was analyzed. The characterization of mutant lines revealed differences in root and stem lengths, and rosette area size. Plants with a disrupted AtDSS1(V) gene exhibited lower survival rates and increased levels of oxidized proteins in comparison to WT plants exposed to oxidative stress induced by hydrogen peroxide. In this work, the dss1 double mutant was not obtained due to embryonic lethality. These results suggest that the DSS1(V) protein could be an important molecular component in plant abiotic stress response.
Collapse
|
8
|
Quezada-Martinez D, Zou J, Zhang W, Meng J, Batley J, Mason AS. Allele segregation analysis of F 1 hybrids between independent Brassica allohexaploid lineages. Chromosoma 2022; 131:147-161. [PMID: 35511360 PMCID: PMC9470611 DOI: 10.1007/s00412-022-00774-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 11/29/2022]
Abstract
In the Brassica genus, we find both diploid species (one genome) and allotetraploid species (two different genomes) but no naturally occurring hexaploid species (three different genomes, AABBCC). Although hexaploids can be produced via human intervention, these neo-polyploids have quite unstable genomes and usually suffer from severe genome reshuffling. Whether these genome rearrangements continue in later generations and whether genomic arrangements follow similar, reproducible patterns between different lineages is still unknown. We crossed Brassica hexaploids resulting from different species combinations to produce five F1 hybrids and analyzed the karyotypes of the parents and the F1 hybrids, as well as allele segregation in a resulting test-cross population via molecular karyotyping using SNP array genotyping. Although some genomic regions were found to be more likely to be duplicated, deleted, or rearranged, a consensus pattern was not shared between genotypes. Brassica hexaploids had a high tolerance for fixed structural rearrangements, but which rearrangements occur and become fixed over many generations does not seem to show either strong reproducibility or to indicate selection for stability. On average, we observed 10 de novo chromosome rearrangements contributed almost equally from both parents to the F1 hybrids. At the same time, the F1 hybrid meiosis produced on average 8.6 new rearrangements. Hence, the increased heterozygosity in the F1 hybrid did not significantly improve genome stability in our hexaploid hybrids and might have had the opposite effect. However, hybridization between lineages was readily achieved and may be exploited for future genetics and breeding purposes.
Collapse
Affiliation(s)
- Daniela Quezada-Martinez
- Plant Breeding Department, University of Bonn, 53115, Bonn, Germany.,Plant Breeding Department, Justus Liebig University, 35392, Giessen, Germany
| | - Jun Zou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Wenshan Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jinling Meng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jacqueline Batley
- School of Biological Sciences, The University of Western Australia, Crawley 6009, Perth, Australia
| | - Annaliese S Mason
- Plant Breeding Department, University of Bonn, 53115, Bonn, Germany. .,Plant Breeding Department, Justus Liebig University, 35392, Giessen, Germany.
| |
Collapse
|
9
|
Milsted C, Dai B, Garcia N, Yin L, He Y, Kianian S, Pawlowski W, Chen C. Genome-wide investigation of maize RAD51 binding affinity through phage display. BMC Genomics 2022; 23:199. [PMID: 35279087 PMCID: PMC8917730 DOI: 10.1186/s12864-022-08419-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Accepted: 02/18/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND RAD51 proteins, which are conserved in all eukaryotes, repair DNA double-strand breaks. This is critical to homologous chromosome pairing and recombination enabling successful reproduction. Work in Arabidopsis suggests that RAD51 also plays a role in plant defense; the Arabidopsis rad51 mutant is more susceptible to Pseudomonas syringae. However, the defense functions of RAD51 and the proteins interacting with RAD51 have not been thoroughly investigated in maize. Uncovering ligands of RAD51 would help to understand meiotic recombination and possibly the role of RAD51 in defense. This study used phage display, a tool for discovery of protein-protein interactions, to search for proteins interacting with maize RAD51A1. RESULTS Maize RAD51A1 was screened against a random phage library. Eleven short peptide sequences were recovered from 15 phages which bound ZmRAD51A1 in vitro; three sequences were found in multiple successfully binding phages. Nine of these phage interactions were verified in vitro through ELISA and/or dot blotting. BLAST searches did not reveal any maize proteins which contained the exact sequence of any of the selected phage peptides, although one of the selected phages had a strong alignment (E-value = 0.079) to a binding domain of maize BRCA2. Therefore, we designed 32 additional short peptides using amino acid sequences found in the predicted maize proteome. These peptides were not contained within phages. Of these synthesized peptides, 14 bound to ZmRAD51A1 in a dot blot experiment. These 14 sequences are found in known maize proteins including transcription factors putatively involved in defense. CONCLUSIONS These results reveal several peptides which bind ZmRAD51A1 and support a potential role for ZmRAD51A1 in transcriptional regulation and plant defense. This study also demonstrates the applicability of phage display to basic science questions, such as the search for binding partners of a known protein, and raises the possibility of an iterated approach to test peptide sequences that closely but imperfectly align with the selected phages.
Collapse
Affiliation(s)
- Claire Milsted
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, 85287, USA
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA
| | - Bo Dai
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA
| | - Nelson Garcia
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA
- Calyxt Inc, 2800 Mount Ridge Rd, Roseville, MN, 55113, USA
| | - Lu Yin
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, 85287, USA
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA
| | - Yan He
- School of Integrative Plant Science, Cornell University, 401 Bradfield Hall, Ithaca, NY, 14853, USA
- National Maize Improvement Center of China, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100094, China
| | - Shahryar Kianian
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA
- Cereal Disease Lab, USDA-ARS, St. Paul, MN, 55108, USA
| | - Wojciech Pawlowski
- School of Integrative Plant Science, Cornell University, 401 Bradfield Hall, Ithaca, NY, 14853, USA
| | - Changbin Chen
- School of Life Sciences, Arizona State University, 427 E Tyler Mall, Tempe, AZ, 85287, USA.
- Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, St. Paul, MN, 55108, USA.
| |
Collapse
|
10
|
Bianco PR. OB-fold Families of Genome Guardians: A Universal Theme Constructed From the Small β-barrel Building Block. Front Mol Biosci 2022; 9:784451. [PMID: 35223988 PMCID: PMC8881015 DOI: 10.3389/fmolb.2022.784451] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
The maintenance of genome stability requires the coordinated actions of multiple proteins and protein complexes, that are collectively known as genome guardians. Within this broadly defined family is a subset of proteins that contain oligonucleotide/oligosaccharide-binding folds (OB-fold). While OB-folds are widely associated with binding to single-stranded DNA this view is no longer an accurate depiction of how these domains are utilized. Instead, the core of the OB-fold is modified and adapted to facilitate binding to a variety of DNA substrates (both single- and double-stranded), phospholipids, and proteins, as well as enabling catalytic function to a multi-subunit complex. The flexibility accompanied by distinctive oligomerization states and quaternary structures enables OB-fold genome guardians to maintain the integrity of the genome via a myriad of complex and dynamic, protein-protein; protein-DNA, and protein-lipid interactions in both prokaryotes and eukaryotes.
Collapse
Affiliation(s)
- Piero R. Bianco
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, United States
| |
Collapse
|
11
|
Vu TV, Das S, Nguyen CC, Kim J, Kim JY. Single-strand annealing: Molecular mechanisms and potential applications in CRISPR-Cas-based precision genome editing. Biotechnol J 2021; 17:e2100413. [PMID: 34846104 DOI: 10.1002/biot.202100413] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/22/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Spontaneous double-stranded DNA breaks (DSBs) frequently occur within the genome of all living organisms and must be well repaired for survival. Recently, more important roles of the DSB repair pathways that were previously thought to be minor pathways, such as single-strand annealing (SSA), have been shown. Nevertheless, the biochemical mechanisms and applications of the SSA pathway in genome editing have not been updated. PURPOSE AND SCOPE Understanding the molecular mechanism of SSA is important to design potential applications in gene editing. This review provides insights into the recent progress of SSA studies and establishes a model for their potential applications in precision genome editing. SUMMARY AND CONCLUSION The SSA mechanism involved in DNA DSB repair appears to be activated by a complex signaling cascade starting with broken end sensing and 5'-3' resection to reveal homologous repeats on the 3' ssDNA overhangs that flank the DSB. Annealing the repeats would help to amend the discontinuous ends and restore the intact genome, resulting in the missing of one repeat and the intervening sequence between the repeats. We proposed a model for CRISPR-Cas-based precision insertion or replacement of DNA fragments to take advantage of the characteristics. The proposed model can add a tool to extend the choice for precision gene editing. Nevertheless, the model needs to be experimentally validated and optimized with SSA-favorable conditions for practical applications.
Collapse
Affiliation(s)
- Tien Van Vu
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,National Key Laboratory for Plant Cell Biotechnology, Agricultural Genetics Institute, Bac Tu Liem, Hanoi, Vietnam
| | - Swati Das
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Cam Chau Nguyen
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jihae Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Four Program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Republic of Korea.,Division of Life Science, Gyeongsang National University, Jinju, Republic of Korea
| |
Collapse
|
12
|
Gutiérrez Pinzón Y, González Kise JK, Rueda P, Ronceret A. The Formation of Bivalents and the Control of Plant Meiotic Recombination. FRONTIERS IN PLANT SCIENCE 2021; 12:717423. [PMID: 34557215 PMCID: PMC8453087 DOI: 10.3389/fpls.2021.717423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/13/2021] [Indexed: 06/06/2023]
Abstract
During the first meiotic division, the segregation of homologous chromosomes depends on the physical association of the recombined homologous DNA molecules. The physical tension due to the sites of crossing-overs (COs) is essential for the meiotic spindle to segregate the connected homologous chromosomes to the opposite poles of the cell. This equilibrated partition of homologous chromosomes allows the first meiotic reductional division. Thus, the segregation of homologous chromosomes is dependent on their recombination. In this review, we will detail the recent advances in the knowledge of the mechanisms of recombination and bivalent formation in plants. In plants, the absence of meiotic checkpoints allows observation of subsequent meiotic events in absence of meiotic recombination or defective meiotic chromosomal axis formation such as univalent formation instead of bivalents. Recent discoveries, mainly made in Arabidopsis, rice, and maize, have highlighted the link between the machinery of double-strand break (DSB) formation and elements of the chromosomal axis. We will also discuss the implications of what we know about the mechanisms regulating the number and spacing of COs (obligate CO, CO homeostasis, and interference) in model and crop plants.
Collapse
|
13
|
Le HP, Heyer WD, Liu J. Guardians of the Genome: BRCA2 and Its Partners. Genes (Basel) 2021; 12:genes12081229. [PMID: 34440403 PMCID: PMC8394001 DOI: 10.3390/genes12081229] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/28/2022] Open
Abstract
The tumor suppressor BRCA2 functions as a central caretaker of genome stability, and individuals who carry BRCA2 mutations are predisposed to breast, ovarian, and other cancers. Recent research advanced our mechanistic understanding of BRCA2 and its various interaction partners in DNA repair, DNA replication support, and DNA double-strand break repair pathway choice. In this review, we discuss the biochemical and structural properties of BRCA2 and examine how these fundamental properties contribute to DNA repair and replication fork stabilization in living cells. We highlight selected BRCA2 binding partners and discuss their role in BRCA2-mediated homologous recombination and fork protection. Improved mechanistic understanding of how BRCA2 functions in genome stability maintenance can enable experimental evidence-based evaluation of pathogenic BRCA2 mutations and BRCA2 pseudo-revertants to support targeted therapy.
Collapse
Affiliation(s)
- Hang Phuong Le
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Jie Liu
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA; (H.P.L.); (W.-D.H.)
- Correspondence: ; Tel.: +1-530-752-3016
| |
Collapse
|
14
|
Ghouil R, Miron S, Koornneef L, Veerman J, Paul MW, Le Du MH, Sleddens-Linkels E, van Rossum-Fikkert SE, van Loon Y, Felipe-Medina N, Pendas AM, Maas A, Essers J, Legrand P, Baarends WM, Kanaar R, Zinn-Justin S, Zelensky AN. BRCA2 binding through a cryptic repeated motif to HSF2BP oligomers does not impact meiotic recombination. Nat Commun 2021; 12:4605. [PMID: 34326328 PMCID: PMC8322138 DOI: 10.1038/s41467-021-24871-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
BRCA2 and its interactors are required for meiotic homologous recombination (HR) and fertility. Loss of HSF2BP, a BRCA2 interactor, disrupts HR during spermatogenesis. We test the model postulating that HSF2BP localizes BRCA2 to meiotic HR sites, by solving the crystal structure of the BRCA2 fragment in complex with dimeric armadillo domain (ARM) of HSF2BP and disrupting this interaction in a mouse model. This reveals a repeated 23 amino acid motif in BRCA2, each binding the same conserved surface of one ARM domain. In the complex, two BRCA2 fragments hold together two ARM dimers, through a large interface responsible for the nanomolar affinity - the strongest interaction involving BRCA2 measured so far. Deleting exon 12, encoding the first repeat, from mBrca2 disrupts BRCA2 binding to HSF2BP, but does not phenocopy HSF2BP loss. Thus, results herein suggest that the high-affinity oligomerization-inducing BRCA2-HSF2BP interaction is not required for RAD51 and DMC1 recombinase localization in meiotic HR.
Collapse
Affiliation(s)
- Rania Ghouil
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette, France
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette, France
| | - Lieke Koornneef
- Department of Developmental Biology, Oncode Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Jasper Veerman
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Marie-Hélène Le Du
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette, France
| | - Esther Sleddens-Linkels
- Department of Developmental Biology, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Sari E van Rossum-Fikkert
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands.,Department of Radiation Oncology, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Yvette van Loon
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Natalia Felipe-Medina
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | - Alberto M Pendas
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer (CSIC-Universidad de Salamanca), Salamanca, Spain
| | - Alex Maas
- Department of Cell Biology, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Jeroen Essers
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands.,Department of Radiation Oncology, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands.,Department of Vascular Surgery, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Pierre Legrand
- Synchrotron SOLEIL, L'Orme des Merisiers, Gif-sur-Yvette, France
| | - Willy M Baarends
- Department of Developmental Biology, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands.
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette, France.
| | - Alex N Zelensky
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3000 CA, Rotterdam, The Netherlands.
| |
Collapse
|
15
|
Julien M, Ghouil R, Petitalot A, Caputo SM, Carreira A, Zinn-Justin S. Intrinsic Disorder and Phosphorylation in BRCA2 Facilitate Tight Regulation of Multiple Conserved Binding Events. Biomolecules 2021; 11:1060. [PMID: 34356684 PMCID: PMC8301801 DOI: 10.3390/biom11071060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 12/26/2022] Open
Abstract
The maintenance of genome integrity in the cell is an essential process for the accurate transmission of the genetic material. BRCA2 participates in this process at several levels, including DNA repair by homologous recombination, protection of stalled replication forks, and cell division. These activities are regulated and coordinated via cell-cycle dependent modifications. Pathogenic variants in BRCA2 cause genome instability and are associated with breast and/or ovarian cancers. BRCA2 is a very large protein of 3418 amino acids. Most well-characterized variants causing a strong predisposition to cancer are mutated in the C-terminal 700 residues DNA binding domain of BRCA2. The rest of the BRCA2 protein is predicted to be disordered. Interactions involving intrinsically disordered regions (IDRs) remain difficult to identify both using bioinformatics tools and performing experimental assays. However, the lack of well-structured binding sites provides unique functional opportunities for BRCA2 to bind to a large set of partners in a tightly regulated manner. We here summarize the predictive and experimental arguments that support the presence of disorder in BRCA2. We describe how BRCA2 IDRs mediate self-assembly and binding to partners during DNA double-strand break repair, mitosis, and meiosis. We highlight how phosphorylation by DNA repair and cell-cycle kinases regulate these interactions. We finally discuss the impact of cancer-associated variants on the function of BRCA2 IDRs and more generally on genome stability and cancer risk.
Collapse
Affiliation(s)
- Manon Julien
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91190 Gif-sur-Yvette, France; (M.J.); (R.G.)
- L’Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198, Paris-Saclay University, 91190 Gif-sur-Yvette, France;
| | - Rania Ghouil
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91190 Gif-sur-Yvette, France; (M.J.); (R.G.)
- L’Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198, Paris-Saclay University, 91190 Gif-sur-Yvette, France;
| | - Ambre Petitalot
- Service de Génétique, Unité de Génétique Constitutionnelle, Institut Curie, 75005 Paris, France; (A.P.); (S.M.C.)
- Institut Curie, Paris Sciences Lettres Research University, 75005 Paris, France
| | - Sandrine M. Caputo
- Service de Génétique, Unité de Génétique Constitutionnelle, Institut Curie, 75005 Paris, France; (A.P.); (S.M.C.)
- Institut Curie, Paris Sciences Lettres Research University, 75005 Paris, France
| | - Aura Carreira
- L’Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198, Paris-Saclay University, 91190 Gif-sur-Yvette, France;
- Institut Curie, Paris Sciences Lettres Research University, 75005 Paris, France
- Unité Intégrité du Génome, ARN et Cancer, Institut Curie, CNRS UMR3348, 91405 Orsay, France
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, 91190 Gif-sur-Yvette, France; (M.J.); (R.G.)
- L’Institut de Biologie Intégrative de la Cellule (I2BC), UMR 9198, Paris-Saclay University, 91190 Gif-sur-Yvette, France;
| |
Collapse
|
16
|
Nikolić IP, Nešić SB, Samardžić JT, Timotijević GS. Intrinsically disordered protein AtDSS1(V) participates in plant defense response to oxidative stress. PROTOPLASMA 2021; 258:779-792. [PMID: 33404921 DOI: 10.1007/s00709-020-01598-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
DSS1 is a small protein, highly conserved across different species. As a member of the intrinsically disordered protein family, DSS1 interacts with different protein partners, thus forming complexes involved in diverse biological mechanisms: DNA repair, regulation of protein homeostasis, mRNA export, etc. Additionally, DSS1 has a novel intriguing role in the post-translational protein modification named DSSylation. Oxidatively damaged proteins are targeted for removal with DSS1 and then degraded by proteasome. Yet, DSS1 involvement in the maintenance of genome integrity through homologous recombination is the only function well studied in Arabidopsis research. The fact that animal DSS1 shows wide multifunctionality imposes a need to investigate the additional roles of two Arabidopsis thaliana DSS1 homologs. Having in mind the universality of various biological processes, we considered the possibility of plant DSS1 involvement in cellular homeostasis maintenance during stress exposure. Using real-time PCR and immunoblot analysis, we investigated the profiles of DSS1 gene and protein expression under oxidative stress. We grew and selected the homozygous Arabidopsis mutant line, carrying the T-DNA intron insertion in the DSS1(V) gene. The mutant line was phenotypically described during plant development, and its sensitivity to oxidative stress was characterized. This is the first report which indicates that plant DSS1 gene expression has an altered profile under the influence of oxidative stress. dss1(V)-/- plants showed an increased sensitivity to oxidative stress, germinated faster than WT, but generally showed developmental delay in further stages. Our results indicate that the DSS1 protein could be a crucial player in the molecular mechanisms underlying plant abiotic stress responses.
Collapse
Affiliation(s)
- Ivana P Nikolić
- Institute of Molecular Genetics and Genetic Engineering, Laboratory for Plant Molecular Biology, University of Belgrade, Vojvode Stepe 444a, Belgrade 152, 11042, Serbia
| | - Sofija B Nešić
- Institute of Molecular Genetics and Genetic Engineering, Laboratory for Plant Molecular Biology, University of Belgrade, Vojvode Stepe 444a, Belgrade 152, 11042, Serbia
| | - Jelena T Samardžić
- Institute of Molecular Genetics and Genetic Engineering, Laboratory for Plant Molecular Biology, University of Belgrade, Vojvode Stepe 444a, Belgrade 152, 11042, Serbia
| | - Gordana S Timotijević
- Institute of Molecular Genetics and Genetic Engineering, Laboratory for Plant Molecular Biology, University of Belgrade, Vojvode Stepe 444a, Belgrade 152, 11042, Serbia.
| |
Collapse
|
17
|
Mhaskar AN, Koornneef L, Zelensky AN, Houtsmuller AB, Baarends WM. High Resolution View on the Regulation of Recombinase Accumulation in Mammalian Meiosis. Front Cell Dev Biol 2021; 9:672191. [PMID: 34109178 PMCID: PMC8181746 DOI: 10.3389/fcell.2021.672191] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/19/2021] [Indexed: 11/19/2022] Open
Abstract
A distinguishing feature of meiotic DNA double-strand breaks (DSBs), compared to DSBs in somatic cells, is the fact that they are induced in a programmed and specifically orchestrated manner, which includes chromatin remodeling prior to DSB induction. In addition, the meiotic homologous recombination (HR) repair process that follows, is different from HR repair of accidental DSBs in somatic cells. For instance, meiotic HR involves preferred use of the homolog instead of the sister chromatid as a repair template and subsequent formation of crossovers and non-crossovers in a tightly regulated manner. An important outcome of this distinct repair pathway is the pairing of homologous chromosomes. Central to the initial steps in homology recognition during meiotic HR is the cooperation between the strand exchange proteins (recombinases) RAD51 and its meiosis-specific paralog DMC1. Despite our understanding of their enzymatic activity, details on the regulation of their assembly and subsequent molecular organization at meiotic DSBs in mammals have remained largely enigmatic. In this review, we summarize recent mouse data on recombinase regulation via meiosis-specific factors. Also, we reflect on bulk “omics” studies of initial meiotic DSB processing, compare these with studies using super-resolution microscopy in single cells, at single DSB sites, and explore the implications of these findings for our understanding of the molecular mechanisms underlying meiotic HR regulation.
Collapse
Affiliation(s)
- Aditya N Mhaskar
- Department of Developmental Biology, Erasmus MC, Rotterdam, Netherlands
| | - Lieke Koornneef
- Department of Developmental Biology, Erasmus MC, Rotterdam, Netherlands.,Oncode Institute, Utrecht, Netherlands
| | - Alex N Zelensky
- Department of Molecular Genetics, Erasmus MC, Rotterdam, Netherlands
| | - Adriaan B Houtsmuller
- Erasmus Optical Imaging Centre, Department of Pathology, Erasmus MC, Rotterdam, Netherlands.,Department of Pathology, Erasmus MC, Rotterdam, Netherlands
| | - Willy M Baarends
- Department of Developmental Biology, Erasmus MC, Rotterdam, Netherlands
| |
Collapse
|
18
|
Takemoto K, Tani N, Takada-Horisawa Y, Fujimura S, Tanno N, Yamane M, Okamura K, Sugimoto M, Araki K, Ishiguro KI. Meiosis-Specific C19orf57/4930432K21Rik/BRME1 Modulates Localization of RAD51 and DMC1 to DSBs in Mouse Meiotic Recombination. Cell Rep 2021; 31:107686. [PMID: 32460033 DOI: 10.1016/j.celrep.2020.107686] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/16/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022] Open
Abstract
Meiotic recombination is critical for genetic exchange and generation of chiasmata that ensures faithful chromosome segregation during meiosis I. Meiotic recombination is initiated by DNA double-strand break (DSB) followed by multiple processes of DNA repair. The exact mechanisms for how recombinases localize to DSB remain elusive. Here, we show that C19orf57/4930432K21Rik/BRME1 is a player for meiotic recombination in mice. C19orf57/4930432K21Rik/BRME1 associates with single-stranded DNA (ssDNA) binding proteins, BRCA2 and MEILB2/HSF2BP, which are critical recruiters of recombinases onto DSB sites. Disruption of C19orf57/4930432K21Rik/BRME1 shows severe impact on DSB repair and male fertility. Remarkably, removal of ssDNA binding proteins from DSB sites is delayed, and reciprocally, the loading of RAD51 and DMC1 onto resected ssDNA is impaired in Brme1 knockout (KO) spermatocytes. We propose that C19orf57/4930432K21Rik/BRME1 modulates localization of recombinases to meiotic DSB sites through the interaction with the BRCA2-MEILB2/HSF2BP complex during meiotic recombination.
Collapse
Affiliation(s)
- Kazumasa Takemoto
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan; Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
| | - Naoki Tani
- Liaison Laboratory Research Promotion Center, IMEG, Kumamoto University, Kumamoto 860-0811, Japan
| | - Yuki Takada-Horisawa
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Sayoko Fujimura
- Liaison Laboratory Research Promotion Center, IMEG, Kumamoto University, Kumamoto 860-0811, Japan
| | - Nobuhiro Tanno
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Mariko Yamane
- RIKEN, Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Kaho Okamura
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Michihiko Sugimoto
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis, Kumamoto University, Kumamoto 860-0811, Japan; Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto 860-0811, Japan
| | - Kei-Ichiro Ishiguro
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan.
| |
Collapse
|
19
|
Li Q, Engebrecht J. BRCA1 and BRCA2 Tumor Suppressor Function in Meiosis. Front Cell Dev Biol 2021; 9:668309. [PMID: 33996823 PMCID: PMC8121103 DOI: 10.3389/fcell.2021.668309] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/19/2021] [Indexed: 12/12/2022] Open
Abstract
Meiosis is a specialized cell cycle that results in the production of haploid gametes for sexual reproduction. During meiosis, homologous chromosomes are connected by chiasmata, the physical manifestation of crossovers. Crossovers are formed by the repair of intentionally induced double strand breaks by homologous recombination and facilitate chromosome alignment on the meiotic spindle and proper chromosome segregation. While it is well established that the tumor suppressors BRCA1 and BRCA2 function in DNA repair and homologous recombination in somatic cells, the functions of BRCA1 and BRCA2 in meiosis have received less attention. Recent studies in both mice and the nematode Caenorhabditis elegans have provided insight into the roles of these tumor suppressors in a number of meiotic processes, revealing both conserved and organism-specific functions. BRCA1 forms an E3 ubiquitin ligase as a heterodimer with BARD1 and appears to have regulatory roles in a number of key meiotic processes. BRCA2 is a very large protein that plays an intimate role in homologous recombination. As women with no indication of cancer but carrying BRCA mutations show decreased ovarian reserve and accumulated oocyte DNA damage, studies in these systems may provide insight into why BRCA mutations impact reproductive success in addition to their established roles in cancer.
Collapse
Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA, United States
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA, United States
| |
Collapse
|
20
|
Fu R, Wang C, Shen H, Zhang J, Higgins JD, Liang W. Rice OsBRCA2 Is Required for DNA Double-Strand Break Repair in Meiotic Cells. FRONTIERS IN PLANT SCIENCE 2020; 11:600820. [PMID: 33304374 PMCID: PMC7701097 DOI: 10.3389/fpls.2020.600820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/27/2020] [Indexed: 06/06/2023]
Abstract
The mammalian BREAST CANCER 2 (BRCA2) gene is a tumor suppressor that plays a crucial role in DNA repair and homologous recombination (HR). Here, we report the identification and characterization of OsBRCA2, the rice orthologue of human BRCA2. Osbrca2 mutant plants exhibit normal vegetative growth but experience complete male and female sterility as a consequence of severe meiotic defects. Pairing, synapsis and recombination are impaired in osbrca2 male meiocytes, leading to chromosome entanglements and fragmentation. In the absence of OsBRCA2, localization to the meiotic chromosome axes of the strand-invasion proteins OsRAD51 and OsDMC1 is severely reduced and in vitro OsBRCA2 directly interacts with OsRAD51 and OsDMC1. These results indicate that OsBRCA2 is essential for facilitating the loading of OsRAD51 and OsDMC1 onto resected ends of programmed double-strand breaks (DSB) during meiosis to promote single-end invasions of homologous chromosomes and accurate recombination. In addition, treatment of osbrca2-1 seedlings with mitomycin C (MMC) led to hypersensitivity. As MMC is a genotoxic agent that creates DNA lesions in the somatic cells that can only be repaired by HR, these results suggest that OsBRCA2 has a conserved role in DSB repair and HR in rice.
Collapse
Affiliation(s)
- Ruifeng Fu
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chong Wang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongyu Shen
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Zhang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - James D. Higgins
- Department of Genetics and Genome Biology, University of Leicester,Leicester, United Kingdom
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| |
Collapse
|
21
|
Shinoyama H, Ichikawa H, Nishizawa-Yokoi A, Skaptsov M, Toki S. Simultaneous TALEN-mediated knockout of chrysanthemum DMC1 genes confers male and female sterility. Sci Rep 2020; 10:16165. [PMID: 32999297 PMCID: PMC7527520 DOI: 10.1038/s41598-020-72356-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 08/30/2020] [Indexed: 02/06/2023] Open
Abstract
Genome editing has become one of the key technologies for plant breeding. However, in polyploid species such as chrysanthemum, knockout of all loci of multiple genes is needed to eliminate functional redundancies. We identified six cDNAs for the CmDMC1 genes involved in meiotic homologous recombination in chrysanthemum. Since all six cDNAs harbored a homologous core region, simultaneous knockout via TALEN-mediated genome editing should be possible. We isolated the CmDMC1 loci corresponding to the six cDNAs and constructed a TALEN-expression vector bearing a CmDMC1 target site containing the homologous core region. After transforming two chrysanthemum cultivars with the TALEN-expression vector, seven lines exhibited disruption of all six CmDMC1 loci at the target site as well as stable male and female sterility at 10–30 °C. This strategy to produce completely sterile plants could be widely applicable to prevent the risk of transgene flow from transgenic plants to their wild relatives.
Collapse
Affiliation(s)
- Harue Shinoyama
- Fukui Agricultural Experiment Station, Fukui, 918-8215, Japan. .,Department of Bioscience, Fukui Prefectural University, Awara, 910-4103, Japan.
| | - Hiroaki Ichikawa
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8604, Japan
| | - Ayako Nishizawa-Yokoi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8604, Japan.,Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Mikhail Skaptsov
- South Siberian Botanical Garden, Altai State University, Barnaul, Russia, 656049
| | - Seiichi Toki
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8604, Japan.,Graduate School of Nanobioscience, Yokohama City University, Yokohama, 236-0027, Japan.,Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813, Japan
| |
Collapse
|
22
|
Physiological and Pathological Roles of RAD52 at DNA Replication Forks. Cancers (Basel) 2020; 12:cancers12020402. [PMID: 32050645 PMCID: PMC7072239 DOI: 10.3390/cancers12020402] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 02/07/2023] Open
Abstract
Understanding basic molecular mechanisms underlying the biology of cancer cells is of outmost importance for identification of novel therapeutic targets and biomarkers for patient stratification and better therapy selection. One of these mechanisms, the response to replication stress, fuels cancer genomic instability. It is also an Achille’s heel of cancer. Thus, identification of pathways used by the cancer cells to respond to replication-stress may assist in the identification of new biomarkers and discovery of new therapeutic targets. Alternative mechanisms that act at perturbed DNA replication forks and involve fork degradation by nucleases emerged as crucial for sensitivity of cancer cells to chemotherapeutics agents inducing replication stress. Despite its important role in homologous recombination and recombinational repair of DNA double strand breaks in lower eukaryotes, RAD52 protein has been considered dispensable in human cells and the full range of its cellular functions remained unclear. Very recently, however, human RAD52 emerged as an important player in multiple aspects of replication fork metabolism under physiological and pathological conditions. In this review, we describe recent advances on RAD52’s key functions at stalled or collapsed DNA replication forks, in particular, the unexpected role of RAD52 as a gatekeeper, which prevents unscheduled processing of DNA. Last, we will discuss how these functions can be exploited using specific inhibitors in targeted therapy or for an informed therapy selection.
Collapse
|
23
|
Van Vu T, Sung YW, Kim J, Doan DTH, Tran MT, Kim JY. Challenges and Perspectives in Homology-Directed Gene Targeting in Monocot Plants. RICE (NEW YORK, N.Y.) 2019; 12:95. [PMID: 31858277 PMCID: PMC6923311 DOI: 10.1186/s12284-019-0355-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/04/2019] [Indexed: 05/18/2023]
Abstract
Continuing crop domestication/redomestication and modification is a key determinant of the adaptation and fulfillment of the food requirements of an exploding global population under increasingly challenging conditions such as climate change and the reduction in arable lands. Monocotyledonous crops are not only responsible for approximately 70% of total global crop production, indicating their important roles in human life, but also the first crops to be challenged with the abovementioned hurdles; hence, monocot crops should be the first to be engineered and/or de novo domesticated/redomesticated. A long time has passed since the first green revolution; the world is again facing the challenge of feeding a predicted 9.7 billion people in 2050, since the decline in world hunger was reversed in 2015. One of the major lessons learned from the first green revolution is the importance of novel and advanced trait-carrying crop varieties that are ideally adapted to new agricultural practices. New plant breeding techniques (NPBTs), such as genome editing, could help us succeed in this mission to create novel and advanced crops. Considering the importance of NPBTs in crop genetic improvement, we attempt to summarize and discuss the latest progress with major approaches, such as site-directed mutagenesis using molecular scissors, base editors and especially homology-directed gene targeting (HGT), a very challenging but potentially highly precise genome modification approach in plants. We therefore suggest potential approaches for the improvement of practical HGT, focusing on monocots, and discuss a potential approach for the regulation of genome-edited products.
Collapse
Affiliation(s)
- Tien Van Vu
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
- National Key Laboratory for Plant Cell Biotechnology, Agricultural Genetics Institute, Km 02, Pham Van Dong Road, Co Nhue 1, Bac Tu Liem, Hanoi, 11917, Vietnam
| | - Yeon Woo Sung
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Jihae Kim
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Duong Thi Hai Doan
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Mil Thi Tran
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Jae-Yean Kim
- Division of Applied Life Science (BK21 Plus program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
- Division of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju, 52828, Republic of Korea.
| |
Collapse
|
24
|
Kumar R, Duhamel M, Coutant E, Ben-Nahia E, Mercier R. Antagonism between BRCA2 and FIGL1 regulates homologous recombination. Nucleic Acids Res 2019; 47:5170-5180. [PMID: 30941419 PMCID: PMC6547764 DOI: 10.1093/nar/gkz225] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 02/06/2023] Open
Abstract
Homologous recombination (HR) maintains genome stability by promoting accurate DNA repair. Two recombinases, RAD51 and DMC1, are central to HR repair and form dynamic nucleoprotein filaments in vivo under tight regulation. However, the interplay between positive and negative regulators to control the dynamic assembly/disassembly of RAD51/DMC1 filaments in multicellular eukaryotes remains poorly characterized. Here, we report an antagonism between BRCA2, a well-studied positive mediator of RAD51/DMC1, and FIDGETIN-LIKE-1 (FIGL1), which we previously proposed as a negative regulator of RAD51/DMC1. Through forward genetic screen, we identified a mutation in one of the two Arabidopsis BRCA2 paralogs that suppresses the meiotic phenotypes of figl1. Consistent with the antagonistic roles of BRCA2 and FIGL1, the figl1 mutation in the brca2 background restores RAD51/DMC1 focus formation and homologous chromosome interaction at meiosis, and RAD51 focus formation in somatic cells. This study shows that BRCA2 and FIGL1 have antagonistic effects on the dynamics of RAD51/DMC1-dependent DNA transactions to promote accurate HR repair.
Collapse
Affiliation(s)
- Rajeev Kumar
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Marine Duhamel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Eve Coutant
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Emna Ben-Nahia
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Raphael Mercier
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| |
Collapse
|
25
|
Identifying a BRCA2 c.5722_5723del mutation in a Han-Chinese family with breast cancer. Biosci Rep 2019; 39:BSR20182471. [PMID: 30940775 PMCID: PMC6488854 DOI: 10.1042/bsr20182471] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 03/19/2019] [Accepted: 04/01/2019] [Indexed: 12/17/2022] Open
Abstract
Breast cancer (BC) is the most common female cancer found worldwide. It is responsible for 25% of all cancer patients in females. Hereditary BC accounts for about 5–10% of all BC cases. The breast cancer 1 gene (BRCA1) and the breast cancer 2 gene (BRCA2) are the two most-studied BC susceptibility genes. Genetic testing for disease-causing mutations in BRCA1, BRCA2, and other BC susceptibility genes is strongly recommended for members of families having a BC family history. The present study found a heterozygous c.5722_5723del mutation in the BRCA2 exon 11 of a large Han-Chinese BC family using whole exome sequencing and Sanger sequencing. It may cause DNA double-strand breaks repair dysfunction by disturbing homologous recombination, further resulting in BC. The study findings may help supplement and further improve genetic testing strategies and BC risk estimation methodologies in China.
Collapse
|
26
|
Pfeffer CM, Ho BN, Singh ATK. The Evolution, Functions and Applications of the Breast Cancer Genes BRCA1 and BRCA2. Cancer Genomics Proteomics 2018; 14:293-298. [PMID: 28870997 DOI: 10.21873/cgp.20040] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 12/17/2022] Open
Abstract
BRCA1 and BRCA2 are both tumor suppressors whose mutations are the cause of most hereditary breast cancers. Both genes are highly involved in ensuring genome stability. BRCA1 homologs are found in the plant and animal kingdoms while BRCA2 homologs are additionally found in the fungi kingdom. The initial origin of both genes remains unknown, however it is expected that the common ancestors originated around 1.6 billion years ago prior to the kingdoms diverging. There has been a great amount of divergence between homologs that is not observed in other tumor suppressors with only functionally important domains conserved. This divergence continues today with evidence of primate BRCA1/2 evolution. Cancer-associated mutations have been found to occur at conserved sites, indicating that conserved sites are important for function. In this study, we present a review on the phylogenesis of BRCA1 and BRCA2.
Collapse
Affiliation(s)
- Claire M Pfeffer
- Department of Biology, Division of Natural and Social Sciences, Carthage College, Kenosha, WI, U.S.A
| | - Benjamin N Ho
- Department of Biology, Division of Natural and Social Sciences, Carthage College, Kenosha, WI, U.S.A
| | - Amareshwar T K Singh
- Department of Biology, Division of Natural and Social Sciences, Carthage College, Kenosha, WI, U.S.A.
| |
Collapse
|
27
|
Hou X, Li T, Ren Z, Liu Y. Novel BRCA2-Interacting Protein, LIMD1, Is Essential for the Centrosome Localization of BRCA2 in Esophageal Cancer Cell. Oncol Res 2017; 24:247-53. [PMID: 27656835 PMCID: PMC7838625 DOI: 10.3727/096504016x14652175055765] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mutation of breast cancer 2, early onset (BRCA2) has been identified as a vital risk factor for esophageal cancer (EC). To date, several proteins have been reported as BRCA2-interacting proteins and are associated with multiple biological processes. This study’s aim was to identify a novel interactive protein of BRCA2 and to explore its functional roles in EC. A yeast two-hybrid screening was performed to identify a novel BRCA2-interacting protein. Glutathione-S-transferase (GST) pull-down analysis was performed to find out how the binding domain of BRCA2 interacts with LIM domains containing 1 (LIMD1). The interaction between LIMD1 and BRCA2 at the endogenous level was confirmed by using coimmunoprecipitation and immunobloting. Furthermore, two different sequences of short hairpin RNAs (shRNAs) against LIMD1 were transfected into the human EC cell line ECA109. Afterward, the effects of LIMD1 suppression on the centrosome localization of BRCA2 and cell division were analyzed using an immunofluorescence microscope. Results showed that LIMD1 was a novel BRCA2-interacting protein, and LIMD1 interacted with the conserved region of BRCA2 (amino acids 2,750–3,094) in vitro. Importantly, after interfering with the protein expression of LIMD1 in ECA109 cells, the centrosome localization of BRCA2 was significantly abolished and abnormal cell division was significantly increased. These results suggested that LIMD1 is a novel BRCA2-interacting protein and is involved in the centrosome localization of BRCA2 and suppression of LIMD1, causing abnormal cell division in EC cells.
Collapse
Affiliation(s)
- Xiaobin Hou
- Department of Thoracic Surgery, Chinese PLA General Hospital, Beijing, China
| | | | | | | |
Collapse
|
28
|
Zhang P, Zhang Y, Sun L, Sinumporn S, Yang Z, Sun B, Xuan D, Li Z, Yu P, Wu W, Wang K, Cao L, Cheng S. The Rice AAA-ATPase OsFIGNL1 Is Essential for Male Meiosis. FRONTIERS IN PLANT SCIENCE 2017; 8:1639. [PMID: 29021797 PMCID: PMC5624289 DOI: 10.3389/fpls.2017.01639] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/06/2017] [Indexed: 05/18/2023]
Abstract
Meiosis is crucial in reproduction of plants and ensuring genetic diversity. Although several genes involved in homologous recombination and DNA repair have been reported, their functions in rice (Oryza sativa) male meiosis remain poorly understood. Here, we isolated and characterized the rice OsFIGNL1 (OsFidgetin-like 1) gene, encoding a conserved AAA-ATPase, and explored its function and importance in male meiosis and pollen formation. The rice Osfignl1 mutant exhibited normal vegetative growth, but failed to produce seeds and displayed pollen abortion phenotype. Phenotypic comparisons between the wild-type and Osfignl1 mutant demonstrated that OsFIGNL1 is required for anther development, and that the recessive mutation of this gene causes male sterility in rice. Complementation and CRISPR/Cas9 experiments demonstrated that wild-type OsFIGNL1 is responsible for the male sterility phenotype. Subcellular localization showed that OsFIGNL1-green fluorescent protein was exclusively localized in the nucleus of rice protoplasts. Male meiosis in the Osfignl1 mutant exhibited abnormal chromosome behavior, including chromosome bridges and multivalent chromosomes at diakinesis, lagging chromosomes, and chromosome fragments during meiosis. Yeast two-hybrid assays demonstrated OsFIGNL1 could interact with RAD51A1, RAD51A2, DMC1A, DMC1B, and these physical interactions were further confirmed by BiFC assay. Taken together, our results suggest that OsFIGNL1 plays an important role in regulation of male meiosis and anther development.
Collapse
Affiliation(s)
- Peipei Zhang
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yingxin Zhang
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Lianping Sun
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Sittipun Sinumporn
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Zhengfu Yang
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Bin Sun
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Dandan Xuan
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Zihe Li
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Ping Yu
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Weixun Wu
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Kejian Wang
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
| | - Liyong Cao
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- *Correspondence: Liyong Cao, Shihua Cheng,
| | - Shihua Cheng
- Key Laboratory for Zhejiang Super Rice Research and State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, China
- *Correspondence: Liyong Cao, Shihua Cheng,
| |
Collapse
|
29
|
Fradet-Turcotte A, Sitz J, Grapton D, Orthwein A. BRCA2 functions: from DNA repair to replication fork stabilization. Endocr Relat Cancer 2016; 23:T1-T17. [PMID: 27530658 DOI: 10.1530/erc-16-0297] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 08/16/2016] [Indexed: 12/12/2022]
Abstract
Maintaining genomic integrity is essential to preserve normal cellular physiology and to prevent the emergence of several human pathologies including cancer. The breast cancer susceptibility gene 2 (BRCA2, also known as the Fanconi anemia (FA) complementation group D1 (FANCD1)) is a potent tumor suppressor that has been extensively studied in DNA double-stranded break (DSB) repair by homologous recombination (HR). However, BRCA2 participates in numerous other processes central to maintaining genome stability, including DNA replication, telomere homeostasis and cell cycle progression. Consequently, inherited mutations in BRCA2 are associated with an increased risk of breast, ovarian and pancreatic cancers. Furthermore, bi-allelic mutations in BRCA2 are linked to FA, a rare chromosome instability syndrome characterized by aplastic anemia in children as well as susceptibility to leukemia and cancer. Here, we discuss the recent developments underlying the functions of BRCA2 in the maintenance of genomic integrity. The current model places BRCA2 as a central regulator of genome stability by repairing DSBs and limiting replication stress. These findings have direct implications for the development of novel anticancer therapeutic approaches.
Collapse
Affiliation(s)
- Amélie Fradet-Turcotte
- Laval University Cancer Research CenterCHU de Québec Research Center - Université Laval, Hôtel-Dieu de Québec, Oncology Axis, Quebec City, Canada
| | - Justine Sitz
- Laval University Cancer Research CenterCHU de Québec Research Center - Université Laval, Hôtel-Dieu de Québec, Oncology Axis, Quebec City, Canada
| | - Damien Grapton
- Lady Davis Institute for Medical ResearchSegal Cancer Centre, Jewish General Hospital, Montreal, Canada
| | - Alexandre Orthwein
- Lady Davis Institute for Medical ResearchSegal Cancer Centre, Jewish General Hospital, Montreal, Canada Department of OncologyMcGill University, Montreal, Canada
| |
Collapse
|
30
|
BRCA2 regulates DMC1-mediated recombination through the BRC repeats. Proc Natl Acad Sci U S A 2016; 113:3515-20. [PMID: 26976601 DOI: 10.1073/pnas.1601691113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In somatic cells, BRCA2 is needed for RAD51-mediated homologous recombination. The meiosis-specific DNA strand exchange protein, DMC1, promotes the formation of DNA strand invasion products (joint molecules) between homologous molecules in a fashion similar to RAD51. BRCA2 interacts directly with both human RAD51 and DMC1; in the case of RAD51, this interaction results in stimulation of RAD51-promoted DNA strand exchange. However, for DMC1, little is known regarding the basis and functional consequences of its interaction with BRCA2. Here we report that human DMC1 interacts directly with each of the BRC repeats of BRCA2, albeit most tightly with repeats 1-3 and 6-8. However, BRC1-3 bind with higher affinity to RAD51 than to DMC1, whereas BRC6-8 bind with higher affinity to DMC1, providing potential spatial organization to nascent filament formation. With the exception of BRC4, each BRC repeat stimulates joint molecule formation by DMC1. The basis for this stimulation is an enhancement of DMC1-ssDNA complex formation by the stimulatory BRC repeats. Lastly, we demonstrate that full-length BRCA2 protein stimulates DMC1-mediated DNA strand exchange between RPA-ssDNA complexes and duplex DNA, thus identifying BRCA2 as a mediator of DMC1 recombination function. Collectively, our results suggest unique and specialized functions for the BRC motifs of BRCA2 in promoting homologous recombination in meiotic and mitotic cells.
Collapse
|
31
|
Jagadish KSV, Kavi Kishor PB, Bahuguna RN, von Wirén N, Sreenivasulu N. Staying Alive or Going to Die During Terminal Senescence-An Enigma Surrounding Yield Stability. FRONTIERS IN PLANT SCIENCE 2015; 6:1070. [PMID: 26648957 PMCID: PMC4663250 DOI: 10.3389/fpls.2015.01070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/16/2015] [Indexed: 05/02/2023]
Abstract
Breeding programs with the aim to enhance yield productivity under abiotic stress conditions during the reproductive stage of crops is a top priority in the era of climate change. However, the choice of exploring stay-green or senescence phenotypes, which represent an opposing physiological bearing, are explored in cereal breeding programs for enhanced yield stability to a different extent. Thus, the consideration of stay-green or senescence phenotypes is still an ongoing debate and has not been comprehensively addressed. In this review, we provide arguments for designing a target phenotype to mitigate abiotic stresses during pre- and post-anthesis in cereals with a focus on hormonal balances regulating stay-green phenotype versus remobilization. The two major hypothesis for grain yield improvement are (i) the importance of the stay-green trait to elevate grain number under pre-anthesis and anthesis stress and (ii) fine tuning the regulatory and molecular physiological mechanisms to accelerate nutrient remobilization to optimize grain quality and seed weight under post-anthesis stress. We highlight why a cautious balance in the phenotype design is essential. While stay-green phenotypes promise to be ideal for developing stress-tolerant lines during pre-anthesis and fertilization to enhance grain number and yield per se, fine-tuning efficient remobilizing behavior during seed filling might optimize grain weight, grain quality and nutrient efficiency. The proposed model provides novel and focused directions for cereal stress breeding programs to ensure better seed-set and efficient grain-filling in cereals under terminal drought and heat stress exposure.
Collapse
Affiliation(s)
| | | | | | - Nicolaus von Wirén
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Nese Sreenivasulu
- International Rice Research Institute, Metro Manila, Philippines
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| |
Collapse
|
32
|
Mercier R, Mézard C, Jenczewski E, Macaisne N, Grelon M. The molecular biology of meiosis in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:297-327. [PMID: 25494464 DOI: 10.1146/annurev-arplant-050213-035923] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Meiosis is the cell division that reshuffles genetic information between generations. Recently, much progress has been made in understanding this process; in particular, the identification and functional analysis of more than 80 plant genes involved in meiosis have dramatically deepened our knowledge of this peculiar cell division. In this review, we provide an overview of advancements in the understanding of all aspects of plant meiosis, including recombination, chromosome synapsis, cell cycle control, chromosome distribution, and the challenge of polyploidy.
Collapse
Affiliation(s)
- Raphaël Mercier
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; , , , ,
| | | | | | | | | |
Collapse
|
33
|
Klaue D, Kobbe D, Kemmerich F, Kozikowska A, Puchta H, Seidel R. Fork sensing and strand switching control antagonistic activities of RecQ helicases. Nat Commun 2013; 4:2024. [PMID: 23771268 PMCID: PMC3709500 DOI: 10.1038/ncomms3024] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 05/17/2013] [Indexed: 12/16/2022] Open
Abstract
RecQ helicases have essential roles in maintaining genome stability during replication and in controlling double-strand break repair by homologous recombination. Little is known about how the different RecQ helicases found in higher eukaryotes achieve their specialized and partially opposing functions. Here, we investigate the DNA unwinding of RecQ helicases from Arabidopsis thaliana, AtRECQ2 and AtRECQ3 at the single-molecule level using magnetic tweezers. Although AtRECQ2 predominantly unwinds forked DNA substrates in a highly repetitive fashion, AtRECQ3 prefers to rewind, that is, to close preopened DNA forks. For both enzymes, this process is controlled by frequent strand switches and active sensing of the unwinding fork. The relative extent of the strand switches towards unwinding or towards rewinding determines the predominant direction of the enzyme. Our results provide a simple explanation for how different biological activities can be achieved by rather similar members of the RecQ family. RecQ helicases are enzymes that play a central role in maintaining genome stability in the DNA repair cascade. Klaue et al. show that RecQ2 and RecQ3 from Arabidopsis thaliana process DNA by, respectively, unwinding and rewinding forked DNA substrates, using a frequent strand switching mechanism.
Collapse
Affiliation(s)
- Daniel Klaue
- Biotechnology Center, Technische Universität Dresden, Dresden 01062, Germany
| | | | | | | | | | | |
Collapse
|
34
|
Russell JD, Scalf M, Book AJ, Ladror DT, Vierstra RD, Smith LM, Coon JJ. Characterization and quantification of intact 26S proteasome proteins by real-time measurement of intrinsic fluorescence prior to top-down mass spectrometry. PLoS One 2013; 8:e58157. [PMID: 23536786 PMCID: PMC3594244 DOI: 10.1371/journal.pone.0058157] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 02/03/2013] [Indexed: 11/18/2022] Open
Abstract
Quantification of gas-phase intact protein ions by mass spectrometry (MS) is impeded by highly-variable ionization, ion transmission, and ion detection efficiencies. Therefore, quantification of proteins using MS-associated techniques is almost exclusively done after proteolysis where peptides serve as proxies for estimating protein abundance. Advances in instrumentation, protein separations, and informatics have made large-scale sequencing of intact proteins using top-down proteomics accessible to the proteomics community; yet quantification of proteins using a top-down workflow has largely been unaddressed. Here we describe a label-free approach to determine the abundance of intact proteins separated by nanoflow liquid chromatography prior to MS analysis by using solution-phase measurements of ultraviolet light-induced intrinsic fluorescence (UV-IF). UV-IF is measured directly at the electrospray interface just prior to the capillary exit where proteins containing at least one tryptophan residue are readily detected. UV-IF quantification was demonstrated using commercially available protein standards and provided more accurate and precise protein quantification than MS ion current. We evaluated the parallel use of UV-IF and top-down tandem MS for quantification and identification of protein subunits and associated proteins from an affinity-purified 26S proteasome sample from Arabidopsis thaliana. We identified 26 unique proteins and quantified 13 tryptophan-containing species. Our analyses discovered previously unidentified N-terminal processing of the β6 (PBF1) and β7 (PBG1) subunit - such processing of PBG1 may generate a heretofore unknown additional protease active site upon cleavage. In addition, our approach permitted the unambiguous identification and quantification both isoforms of the proteasome-associated protein DSS1.
Collapse
Affiliation(s)
- Jason D. Russell
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Adam J. Book
- Department of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Daniel T. Ladror
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Richard D. Vierstra
- Department of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Lloyd M. Smith
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Joshua J. Coon
- Department of Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- Department of Biomolecular Chemistry, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- Department of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- Genome Center of Wisconsin, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- * E-mail:
| |
Collapse
|
35
|
Trenaman A, Hartley C, Prorocic M, Passos-Silva DG, van den Hoek M, Nechyporuk-Zloy V, Machado CR, McCulloch R. Trypanosoma brucei BRCA2 acts in a life cycle-specific genome stability process and dictates BRC repeat number-dependent RAD51 subnuclear dynamics. Nucleic Acids Res 2012; 41:943-60. [PMID: 23222131 PMCID: PMC3553974 DOI: 10.1093/nar/gks1192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma brucei survives in mammals through antigenic variation, which is driven by RAD51-directed homologous recombination of Variant Surface Glycoproteins (VSG) genes, most of which reside in a subtelomeric repository of >1000 silent genes. A key regulator of RAD51 is BRCA2, which in T. brucei contains a dramatic expansion of a motif that mediates interaction with RAD51, termed the BRC repeats. BRCA2 mutants were made in both tsetse fly-derived and mammal-derived T. brucei, and we show that BRCA2 loss has less impact on the health of the former. In addition, we find that genome instability, a hallmark of BRCA2 loss in other organisms, is only seen in mammal-derived T. brucei. By generating cells expressing BRCA2 variants with altered BRC repeat numbers, we show that the BRC repeat expansion is crucial for RAD51 subnuclear dynamics after DNA damage. Finally, we document surprisingly limited co-localization of BRCA2 and RAD51 in the T. brucei nucleus, and we show that BRCA2 mutants display aberrant cell division, revealing a function distinct from BRC-mediated RAD51 interaction. We propose that BRCA2 acts to maintain the huge VSG repository of T. brucei, and this function has necessitated the evolution of extensive RAD51 interaction via the BRC repeats, allowing re-localization of the recombinase to general genome damage when needed.
Collapse
Affiliation(s)
- Anna Trenaman
- The Wellcome Trust Centre for Molecular Parasitology, College of Medical Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Bjørnstad LG, Meza TJ, Otterlei M, Olafsrud SM, Meza-Zepeda LA, Falnes PØ. Human ALKBH4 interacts with proteins associated with transcription. PLoS One 2012; 7:e49045. [PMID: 23145062 PMCID: PMC3493508 DOI: 10.1371/journal.pone.0049045] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 10/03/2012] [Indexed: 01/24/2023] Open
Abstract
The Fe(II)- and 2-oxoglutarate (2OG)-dependent dioxygenase AlkB from E. coli is a demethylase which repairs alkyl lesions in DNA, as well as RNA, through a direct reversal mechanism. Humans possess nine AlkB homologs (ALKBH1-8 and FTO). ALKBH2 and ALKBH3 display demethylase activities corresponding to that of AlkB, and both ALKBH8 and FTO are RNA modification enzymes. The biochemical functions of the rest of the homologs are still unknown. To increase our knowledge on the functions of ALKBH4 and ALKBH7 we have here performed yeast two-hybrid screens to identify interaction partners of the two proteins. While no high-confidence hits were detected in the case of ALKBH7, several proteins associated with chromatin and/or involved in transcription were found to interact with ALKBH4. For all interaction partners, the regions mediating binding to ALKBH4 comprised domains previously reported to be involved in interaction with DNA or chromatin. Furthermore, some of these partners showed nuclear co-localization with ALKBH4. However, the global gene expression pattern was only marginally altered upon ALKBH4 over-expression, and larger effects were observed in the case of ALKBH7. Although the molecular function of both proteins remains to be revealed, our findings suggest a role for ALKBH4 in regulation of gene expression or chromatin state.
Collapse
Affiliation(s)
- Linn G. Bjørnstad
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
| | - Trine J. Meza
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
| | - Marit Otterlei
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Solveig M. Olafsrud
- Genomics Core Facility, Department of Molecular Biosciences, University of Oslo, Oslo, Norway
- Department of Tumor Biology, the Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Leonardo A. Meza-Zepeda
- Genomics Core Facility, Department of Molecular Biosciences, University of Oslo, Oslo, Norway
- Department of Tumor Biology, the Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Pål Ø. Falnes
- Department of Molecular Biosciences, University of Oslo, Oslo, Norway
- * E-mail:
| |
Collapse
|
37
|
Krejci L, Altmannova V, Spirek M, Zhao X. Homologous recombination and its regulation. Nucleic Acids Res 2012; 40:5795-818. [PMID: 22467216 PMCID: PMC3401455 DOI: 10.1093/nar/gks270] [Citation(s) in RCA: 454] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Homologous recombination (HR) is critical both for repairing DNA lesions in mitosis and for chromosomal pairing and exchange during meiosis. However, some forms of HR can also lead to undesirable DNA rearrangements. Multiple regulatory mechanisms have evolved to ensure that HR takes place at the right time, place and manner. Several of these impinge on the control of Rad51 nucleofilaments that play a central role in HR. Some factors promote the formation of these structures while others lead to their disassembly or the use of alternative repair pathways. In this article, we review these mechanisms in both mitotic and meiotic environments and in different eukaryotic taxa, with an emphasis on yeast and mammal systems. Since mutations in several proteins that regulate Rad51 nucleofilaments are associated with cancer and cancer-prone syndromes, we discuss how understanding their functions can lead to the development of better tools for cancer diagnosis and therapy.
Collapse
Affiliation(s)
- Lumir Krejci
- Department of Biology, Masaryk University, Brno, Czech Republic.
| | | | | | | |
Collapse
|
38
|
Seeliger K, Dukowic-Schulze S, Wurz-Wildersinn R, Pacher M, Puchta H. BRCA2 is a mediator of RAD51- and DMC1-facilitated homologous recombination in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2012; 193:364-75. [PMID: 22077663 DOI: 10.1111/j.1469-8137.2011.03947.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
• Mutations in the breast cancer susceptibility gene 2 (BRCA2) are correlated with hereditary breast cancer in humans. Studies have revealed that mammalian BRCA2 plays crucial roles in DNA repair. Therefore, we wished to define the role of the BRCA2 homologs in Arabidopsis in detail. • As Arabidopsis contains two functional BRCA2 homologs, an Atbrca2 double mutant was generated and analyzed with respect to hypersensitivity to genotoxic agents and recombination frequencies. Cytological studies addressing male and female meiosis were also conducted, and immunolocalization was performed in male meiotic prophase I. • The Atbrca2 double mutant showed hypersensitivity to the cross-linking agent mitomycin C and displayed a dramatic reduction in somatic homologous recombination frequency, especially after double-strand break induction. The loss of AtBRCA2 also led to severe defects in male meiosis and development of the female gametophyte and impeded proper localization of the synaptonemal complex protein AtZYP1 and the recombinases AtRAD51 and AtDMC1. • The results demonstrate that AtBRCA2 is important for both somatic and meiotic homologous recombination. We further show that AtBRCA2 is required for proper meiotic synapsis and mediates the recruitment of AtRAD51 and AtDMC1. Our results suggest that BRCA2 controls single-strand invasion steps during homologous recombination in plants.
Collapse
Affiliation(s)
- Katharina Seeliger
- Botanical Institute II, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | | | | | | | | |
Collapse
|
39
|
Waterworth WM, Drury GE, Bray CM, West CE. Repairing breaks in the plant genome: the importance of keeping it together. THE NEW PHYTOLOGIST 2011; 192:805-822. [PMID: 21988671 DOI: 10.1111/j.1469-8137.2011.03926.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
DNA damage threatens the integrity of the genome and has potentially lethal consequences for the organism. Plant DNA is under continuous assault from endogenous and environmental factors and effective detection and repair of DNA damage are essential to ensure the stability of the genome. One of the most cytotoxic forms of DNA damage are DNA double-strand breaks (DSBs) which fragment chromosomes. Failure to repair DSBs results in loss of large amounts of genetic information which, following cell division, severely compromises daughter cells that receive fragmented chromosomes. This review will survey recent advances in our understanding of plant responses to chromosomal breaks, including the sources of DNA damage, the detection and signalling of DSBs, mechanisms of DSB repair, the role of chromatin structure in repair, DNA damage signalling and the link between plant recombination pathways and transgene integration. These mechanisms are of critical importance for maintenance of plant genome stability and integrity under stress conditions and provide potential targets for the improvement of crop plants both for stress resistance and for increased precision in the generation of genetically improved varieties.
Collapse
Affiliation(s)
| | - Georgina E Drury
- Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Clifford M Bray
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | |
Collapse
|
40
|
Dumont M, Massot S, Doutriaux MP, Gratias A. Characterization of Brca2-deficient plants excludes the role of NHEJ and SSA in the meiotic chromosomal defect phenotype. PLoS One 2011; 6:e26696. [PMID: 22039535 PMCID: PMC3198793 DOI: 10.1371/journal.pone.0026696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 10/02/2011] [Indexed: 12/22/2022] Open
Abstract
In somatic cells, three major pathways are involved in the repair of DNA double-strand breaks (DBS): Non-Homologous End Joining (NHEJ), Single-Strand Annealing (SSA) and Homologous Recombination (HR). In somatic and meiotic HR, DNA DSB are 5′ to 3′ resected, producing long 3′ single-stranded DNA extensions. Brca2 is essential to load the Rad51 recombinase onto these 3′ overhangs. The resulting nucleofilament can thus invade a homologous DNA sequence to copy and restore the original genetic information. In Arabidopsis, the inactivation of Brca2 specifically during meiosis by an RNAi approach results in aberrant chromosome aggregates, chromosomal fragmentation and missegregation leading to a sterility phenotype. We had previously suggested that such chromosomal behaviour could be due to NHEJ. In this study, we show that knock-out plants affected in both BRCA2 genes show the same meiotic phenotype as the RNAi-inactivated plants. Moreover, it is demonstrated that during meiosis, neither NHEJ nor SSA compensate for HR deficiency in BRCA2-inactivated plants. The role of the plant-specific DNA Ligase6 is also excluded. The possible mechanism(s) involved in the formation of these aberrant chromosomal bridges in the absence of HR during meiosis are discussed.
Collapse
Affiliation(s)
- Marilyn Dumont
- Institut de Biologie des Plantes, CNRS UMR8618, Université Paris Sud-11, Orsay, France
| | - Sophie Massot
- Institut de Biologie des Plantes, CNRS UMR8618, Université Paris Sud-11, Orsay, France
| | | | - Ariane Gratias
- Institut de Biologie des Plantes, CNRS UMR8618, Université Paris Sud-11, Orsay, France
- * E-mail:
| |
Collapse
|
41
|
Trapp O, Seeliger K, Puchta H. Homologs of breast cancer genes in plants. FRONTIERS IN PLANT SCIENCE 2011; 2:19. [PMID: 22629260 PMCID: PMC3355568 DOI: 10.3389/fpls.2011.00019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 06/02/2011] [Indexed: 05/22/2023]
Abstract
Since the initial discovery of genes involved in hereditary breast cancer in humans, a vast wealth of information has been published. Breast cancer proteins were shown to work as tumor suppressors primarily through their involvement in DNA-damage repair. Surprisingly, homologs of these genes can be found in plant genomes, as well. Here, we want to give an overview of the identification and characterization of the biological roles of these proteins, in plants. In addition to the conservation of their function in DNA repair, new plant-specific characteristics have been revealed. BRCA1 is required for the efficient repair of double strand breaks (DSB) by homologous recombination in somatic cells of the model plant Arabidopsis thaliana. Bioinformatic analysis indicates that, whereas most homologs of key components of the different mammalian BRCA1 complexes are present in plant genomes, homologs of most factors involved in the recruitment of BRCA1 to the DSB cannot be identified. Thus, it is not clear at the moment whether differences exist between plants and animals at this important step. The most conserved region of BRCA1 and BARD1 homologs in plants is a PHD domain which is absent in mammals and which, in AtBARD1, might be involved in the transcriptional regulation of plant development. The presence of a plant-specific domain prompted us to reevaluate the current model for the evolution of BRCA1 homologs and to suggest a new hypothesis, in which we postulate that plant BRCA1 and BARD1 have one common predecessor that gained a PHD domain before duplication. Furthermore, work in Arabidopsis demonstrates that - as in animals - BRCA2 homologs are important for meiotic DNA recombination. Surprisingly, recent research has revealed that AtBRCA2 also has an important role in systemic acquired resistance. In Arabidopsis, BRCA2 is involved in the transcriptional regulation of pathogenesis-related (PR) genes via its interaction with the strand exchange protein RAD51.
Collapse
Affiliation(s)
- Oliver Trapp
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Katharina Seeliger
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| |
Collapse
|
42
|
Osman K, Higgins JD, Sanchez-Moran E, Armstrong SJ, Franklin FCH. Pathways to meiotic recombination in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2011; 190:523-44. [PMID: 21366595 DOI: 10.1111/j.1469-8137.2011.03665.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Meiosis is a central feature of sexual reproduction. Studies in plants have made and continue to make an important contribution to fundamental research aimed at the understanding of this complex process. Moreover, homologous recombination during meiosis provides the basis for plant breeders to create new varieties of crops. The increasing global demand for food, combined with the challenges from climate change, will require sustained efforts in crop improvement. An understanding of the factors that control meiotic recombination has the potential to make an important contribution to this challenge by providing the breeder with the means to make fuller use of the genetic variability that is available within crop species. Cytogenetic studies in plants have provided considerable insights into chromosome organization and behaviour during meiosis. More recently, studies, predominantly in Arabidopsis thaliana, are providing important insights into the genes and proteins that are required for crossover formation during plant meiosis. As a result, substantial progress in the understanding of the molecular mechanisms that underpin meiosis in plants has begun to emerge. This article summarizes current progress in the understanding of meiotic recombination and its control in Arabidopsis. We also assess the relationship between meiotic recombination in Arabidopsis and other eukaryotes, highlighting areas of close similarity and apparent differences.
Collapse
Affiliation(s)
- Kim Osman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | | | | | | | | |
Collapse
|
43
|
Lu Q, Tang X, Tian G, Wang F, Liu K, Nguyen V, Kohalmi SE, Keller WA, Tsang EWT, Harada JJ, Rothstein SJ, Cui Y. Arabidopsis homolog of the yeast TREX-2 mRNA export complex: components and anchoring nucleoporin. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:259-70. [PMID: 19843313 DOI: 10.1111/j.1365-313x.2009.04048.x] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nuclear pore complexes (NPCs) are vital to nuclear-cytoplasmic communication in eukaryotes. The yeast NPC-associated TREX-2 complex, also known as the Thp1-Sac3-Cdc31-Sus1 complex, is anchored on the NPC via the nucleoporin Nup1, and is essential for mRNA export. Here we report the identification and characterization of the putative Arabidopsis thaliana TREX-2 complex and its anchoring nucleoporin. Physical and functional evidence support the identification of the Arabidopsis orthologs of yeast Thp1 and Nup1. Of three Arabidopsis homologs of yeast Sac3, two are putative TREX-2 components, but, surprisingly, none are required for mRNA export as they are in yeast. Physical association of the two Cdc31 homologs, but not the Sus1 homolog, with the TREX-2 complex was observed. In addition to identification of these TREX-2 components, direct interactions of the Arabidopsis homolog of DSS1, which is an established proteasome component in yeast and animals, with both the TREX-2 complex and the proteasome were observed. This suggests the possibility of a link between the two complexes. Thus this work has identified the putative Arabidopsis TREX-2 complex and provides a foundation for future studies of nuclear export in Arabidopsis.
Collapse
Affiliation(s)
- Qing Lu
- Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, ON N5V 4T3, Canada
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Brandão MM, Dantas LL, Silva-Filho MC. AtPIN: Arabidopsis thaliana protein interaction network. BMC Bioinformatics 2009; 10:454. [PMID: 20043823 PMCID: PMC2810305 DOI: 10.1186/1471-2105-10-454] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 12/31/2009] [Indexed: 12/13/2022] Open
Abstract
Background Protein-protein interactions (PPIs) constitute one of the most crucial conditions to sustain life in living organisms. To study PPI in Arabidopsis thaliana we have developed AtPIN, a database and web interface for searching and building interaction networks based on publicly available protein-protein interaction datasets. Description All interactions were divided into experimentally demonstrated or predicted. The PPIs in the AtPIN database present a cellular compartment classification (C3) which divides the PPI into 4 classes according to its interaction evidence and subcellular localization. It has been shown in the literature that a pair of genuine interacting proteins are generally expected to have a common cellular role and proteins that have common interaction partners have a high chance of sharing a common function. In AtPIN, due to its integrative profile, the reliability index for a reported PPI can be postulated in terms of the proportion of interaction partners that two proteins have in common. For this, we implement the Functional Similarity Weight (FSW) calculation for all first level interactions present in AtPIN database. In order to identify target proteins of cytosolic glutamyl-tRNA synthetase (Cyt-gluRS) (AT5G26710) we combined two approaches, AtPIN search and yeast two-hybrid screening. Interestingly, the proteins glutamine synthetase (AT5G35630), a disease resistance protein (AT3G50950) and a zinc finger protein (AT5G24930), which has been predicted as target proteins for Cyt-gluRS by AtPIN, were also detected in the experimental screening. Conclusions AtPIN is a friendly and easy-to-use tool that aggregates information on Arabidopsis thaliana PPIs, ontology, and sub-cellular localization, and might be a useful and reliable strategy to map protein-protein interactions in Arabidopsis. AtPIN can be accessed at http://bioinfo.esalq.usp.br/atpin.
Collapse
Affiliation(s)
- Marcelo M Brandão
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-970 Piracicaba, SP, Brazil.
| | | | | |
Collapse
|
45
|
Chittela RK, Sainis JK. Plant DNA recombinases: a long way to go. J Nucleic Acids 2009; 2010. [PMID: 20798837 PMCID: PMC2925088 DOI: 10.4061/2010/646109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Accepted: 09/08/2009] [Indexed: 01/12/2023] Open
Abstract
DNA homologous recombination is fundamental process by which two homologous DNA molecules exchange the genetic information for the generation of genetic diversity and maintain the genomic integrity. DNA recombinases, a special group of proteins bind to single stranded DNA (ssDNA) nonspecifically and search the double stranded DNA (dsDNA) molecule for a stretch of DNA that is homologous with the bound ssDNA. Recombinase A (RecA) has been well characterized at genetic, biochemical, as well as structural level from prokaryotes. Two homologues of RecA called Rad51 and Dmc1 have been detected in yeast and higher eukaryotes and are known to mediate the homologous recombination in eukaryotes. The biochemistry and mechanism of action of recombinase is important in understanding the process of homologous recombination. Even though considerable progress has been made in yeast and human recombinases, understanding of the plant recombination and recombinases is at nascent stage. Since crop plants are subjected to different breeding techniques, it is important to know the homologous recombination process. This paper focuses on the properties of eukaryotes recombinases and recent developments in the field of plant recombinases Dmc1 and Rad51.
Collapse
Affiliation(s)
- Rajani Kant Chittela
- Plant Biochemistry Section, Molecular Biology Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085, India
| | | |
Collapse
|
46
|
Lin M, Hu B, Chen L, Sun P, Fan Y, Wu P, Chen X. Computational identification of potential molecular interactions in Arabidopsis. PLANT PHYSIOLOGY 2009; 151:34-46. [PMID: 19592425 PMCID: PMC2735983 DOI: 10.1104/pp.109.141317] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 07/06/2009] [Indexed: 05/21/2023]
Abstract
Knowledge of the protein interaction network is useful to assist molecular mechanism studies. Several major repositories have been established to collect and organize reported protein interactions. Many interactions have been reported in several model organisms, yet a very limited number of plant interactions can thus far be found in these major databases. Computational identification of potential plant interactions, therefore, is desired to facilitate relevant research. In this work, we constructed a support vector machine model to predict potential Arabidopsis (Arabidopsis thaliana) protein interactions based on a variety of indirect evidence. In a 100-iteration bootstrap evaluation, the confidence of our predicted interactions was estimated to be 48.67%, and these interactions were expected to cover 29.02% of the entire interactome. The sensitivity of our model was validated with an independent evaluation data set consisting of newly reported interactions that did not overlap with the examples used in model training and testing. Results showed that our model successfully recognized 28.91% of the new interactions, similar to its expected sensitivity (29.02%). Applying this model to all possible Arabidopsis protein pairs resulted in 224,206 potential interactions, which is the largest and most accurate set of predicted Arabidopsis interactions at present. In order to facilitate the use of our results, we present the Predicted Arabidopsis Interactome Resource, with detailed annotations and more specific per interaction confidence measurements. This database and related documents are freely accessible at http://www.cls.zju.edu.cn/pair/.
Collapse
Affiliation(s)
- Mingzhi Lin
- Department of Bioinformatics, Zhejiang University, Hangzhou, People's Republic of China, 310058
| | | | | | | | | | | | | |
Collapse
|
47
|
Abe K, Osakabe K, Ishikawa Y, Tagiri A, Yamanouchi H, Takyuu T, Yoshioka T, Ito T, Kobayashi M, Shinozaki K, Ichikawa H, Toki S. Inefficient double-strand DNA break repair is associated with increased fasciation in Arabidopsis BRCA2 mutants. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2751-61. [PMID: 19457980 PMCID: PMC2692019 DOI: 10.1093/jxb/erp135] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
BRCA2 is a breast tumour susceptibility factor with functions in maintaining genome stability through ensuring efficient double-strand DNA break (DSB) repair via homologous recombination. Although best known in vertebrates, fungi, and higher plants also possess BRCA2-like genes. To investigate the role of Arabidopsis BRCA2 genes in DNA repair in somatic cells, transposon insertion mutants of the AtBRCA2a and AtBRCA2b genes were identified and characterized. atbrca2a-1 and atbrca2b-1 mutant plants showed hypersensitivity to genotoxic stresses compared to wild-type plants. An atbrca2a-1/atbrca2b-1 double mutant showed an additive increase in sensitivity to genotoxic stresses compared to each single mutant. In addition, it was found that atbrca2 mutant plants displayed fasciation and abnormal phyllotaxy phenotypes with low incidence, and that the ratio of plants exhibiting these phenotypes is increased by gamma-irradiation. Interestingly, these phenotypes were also induced by gamma-irradiation in wild-type plants. Moreover, it was found that shoot apical meristems of the atbrca2a-1/atbrca2b-1 double mutant show altered cell cycle progression. These data suggest that inefficient DSB repair in the atbrca2a-1/atbrca2b-1 mutant leads to disorganization of the programmed cell cycle of apical meristems.
Collapse
Affiliation(s)
- Kiyomi Abe
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Keishi Osakabe
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Yuichi Ishikawa
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Akemi Tagiri
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Hiroaki Yamanouchi
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, 2425 Kamimurata, Hitachi-ohmiya, Ibaraki 319-2293, Japan
| | - Toshio Takyuu
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, 2425 Kamimurata, Hitachi-ohmiya, Ibaraki 319-2293, Japan
| | - Terutaka Yoshioka
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, 2425 Kamimurata, Hitachi-ohmiya, Ibaraki 319-2293, Japan
| | - Takuya Ito
- Laboratory of Plant Molecular Biology, RIKEN Tsukuba Institute, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Masatomo Kobayashi
- Experimental Plant Division, RIKEN BioResources Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Plant Science Center, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Hiroaki Ichikawa
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Seiichi Toki
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka Yokohama, Kanagawa 244-0813 Japan
- To whom correspondence should be addressed in Ibaraki. E-mail.
| |
Collapse
|
48
|
Rajanikant C, Melzer M, Rao BJ, Sainis JK. Homologous recombination properties of OsRad51, a recombinase from rice. PLANT MOLECULAR BIOLOGY 2008; 68:479-491. [PMID: 18695945 DOI: 10.1007/s11103-008-9385-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 07/29/2008] [Indexed: 05/26/2023]
Abstract
cDNA corresponding to OsRad51 protein was isolated from cDNA library of rice flowers (Oryza sativa, Indica cultivar group) and cloned in to pET28a expression vector. The protein was over expressed in E. coli BL21 (DE3) and purified. Purified OsRad51 could bind single and double stranded DNA, however it showed higher affinity for single stranded DNA. Transmission Electron Microscopy (TEM) studies of OsRad51-DNA complexes showed that this protein formed ring like structures and bound DNA forming filaments. OsRad51 protein promoted renaturation of complementary single strands in to duplex DNA molecules and also showed ATPase activity, which was stimulated by single strand DNA. Fluorescence resonance energy transfer (FRET) assays revealed that OsRad51 promoted homology dependent renaturation as well as strand exchange reactions. Renaturation activity was ATP dependent; however strand exchange activity was ATP independent. This is the first report on in vitro characterization of Rad51 protein from crop plants.
Collapse
Affiliation(s)
- Chittela Rajanikant
- Plant Biochemistry Section, Molecular Biology Division, Bhabha Atomic Research Center, Mumbai 400085, India
| | | | | | | |
Collapse
|
49
|
Abstract
Homologous recombination (HR) serves to eliminate deleterious lesions, such as double-stranded breaks and interstrand crosslinks, from chromosomes. HR is also critical for the preservation of replication forks, for telomere maintenance, and chromosome segregation in meiosis I. As such, HR is indispensable for the maintenance of genome integrity and the avoidance of cancers in humans. The HR reaction is mediated by a conserved class of enzymes termed recombinases. Two recombinases, Rad51 and Dmc1, catalyze the pairing and shuffling of homologous DNA sequences in eukaryotic cells via a filamentous intermediate on ssDNA called the presynaptic filament. The assembly of the presynaptic filament is a rate-limiting process that is enhanced by recombination mediators, such as the breast tumor suppressor BRCA2. HR accessory factors that facilitate other stages of the Rad51- and Dmc1-catalyzed homologous DNA pairing and strand exchange reaction have also been identified. Recent progress on elucidating the mechanisms of action of Rad51 and Dmc1 and their cohorts of ancillary factors is reviewed here.
Collapse
Affiliation(s)
- Joseph San Filippo
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | |
Collapse
|
50
|
Hartley CL, McCulloch R. Trypanosoma brucei BRCA2 acts in antigenic variation and has undergone a recent expansion in BRC repeat number that is important during homologous recombination. Mol Microbiol 2008; 68:1237-51. [PMID: 18430140 PMCID: PMC2408642 DOI: 10.1111/j.1365-2958.2008.06230.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Antigenic variation in Trypanosoma brucei has selected for the evolution of a massive archive of silent Variant Surface Glycoprotein (VSG) genes, which are activated by recombination into specialized expression sites. Such VSG switching can occur at rates substantially higher than background mutation and is dependent on homologous recombination, a core DNA repair reaction. A key regulator of homologous recombination is BRCA2, a protein that binds RAD51, the enzyme responsible for DNA strand exchange. Here, we show that T. brucei BRCA2 has undergone a recent, striking expansion in the number of BRC repeats, a sequence element that mediates interaction with RAD51. T. brucei BRCA2 mutants are shown to be significantly impaired in antigenic variation and display genome instability. By generating BRCA2 variants with reduced BRC repeat numbers, we show that the BRC expansion is crucial in determining the efficiency of T. brucei homologous recombination and RAD51 localization. Remarkably, however, this appears not to be a major determinant of the activation of at least some VSG genes.
Collapse
Affiliation(s)
- Claire L Hartley
- The Wellcome Centre for Molecular Parasitology and Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow Biomedical Research Centre, 120 University Place, Glasgow G12 8TA, UK
| | | |
Collapse
|