1
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López Ruiz LM, Johnson D, Gittens WH, Brown GGB, Allison RM, Neale MJ. Meiotic prophase length modulates Tel1-dependent DNA double-strand break interference. PLoS Genet 2024; 20:e1011140. [PMID: 38427688 PMCID: PMC10936813 DOI: 10.1371/journal.pgen.1011140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 03/13/2024] [Accepted: 01/17/2024] [Indexed: 03/03/2024] Open
Abstract
During meiosis, genetic recombination is initiated by the formation of many DNA double-strand breaks (DSBs) catalysed by the evolutionarily conserved topoisomerase-like enzyme, Spo11, in preferred genomic sites known as hotspots. DSB formation activates the Tel1/ATM DNA damage responsive (DDR) kinase, locally inhibiting Spo11 activity in adjacent hotspots via a process known as DSB interference. Intriguingly, in S. cerevisiae, over short genomic distances (<15 kb), Spo11 activity displays characteristics of concerted activity or clustering, wherein the frequency of DSB formation in adjacent hotspots is greater than expected by chance. We have proposed that clustering is caused by a limited number of sub-chromosomal domains becoming primed for DSB formation. Here, we provide evidence that DSB clustering is abolished when meiotic prophase timing is extended via deletion of the NDT80 transcription factor. We propose that extension of meiotic prophase enables most cells, and therefore most chromosomal domains within them, to reach an equilibrium state of similar Spo11-DSB potential, reducing the impact that priming has on estimates of coincident DSB formation. Consistent with this view, when Tel1 is absent but Ndt80 is present and thus cells are able to rapidly exit meiotic prophase, genome-wide maps of Spo11-DSB formation are skewed towards pericentromeric regions and regions that load pro-DSB factors early-revealing regions of preferential priming-but this effect is abolished when NDT80 is deleted. Our work highlights how the stochastic nature of Spo11-DSB formation in individual cells within the limited temporal window of meiotic prophase can cause localised DSB clustering-a phenomenon that is exacerbated in tel1Δ cells due to the dual roles that Tel1 has in DSB interference and meiotic prophase checkpoint control.
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Affiliation(s)
- Luz María López Ruiz
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Dominic Johnson
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - William H. Gittens
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - George G. B. Brown
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Rachal M. Allison
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Matthew J. Neale
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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2
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Tan J, Sun X, Zhao H, Guan H, Gao S, Zhou P. Double-strand DNA break repair: molecular mechanisms and therapeutic targets. MedComm (Beijing) 2023; 4:e388. [PMID: 37808268 PMCID: PMC10556206 DOI: 10.1002/mco2.388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/29/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Double-strand break (DSB), a significant DNA damage brought on by ionizing radiation, acts as an initiating signal in tumor radiotherapy, causing cancer cells death. The two primary pathways for DNA DSB repair in mammalian cells are nonhomologous end joining (NHEJ) and homologous recombination (HR), which cooperate and compete with one another to achieve effective repair. The DSB repair mechanism depends on numerous regulatory variables. DSB recognition and the recruitment of DNA repair components, for instance, depend on the MRE11-RAD50-NBS1 (MRN) complex and the Ku70/80 heterodimer/DNA-PKcs (DNA-PK) complex, whose control is crucial in determining the DSB repair pathway choice and efficiency of HR and NHEJ. In-depth elucidation on the DSB repair pathway's molecular mechanisms has greatly facilitated for creation of repair proteins or pathways-specific inhibitors to advance precise cancer therapy and boost the effectiveness of cancer radiotherapy. The architectures, roles, molecular processes, and inhibitors of significant target proteins in the DSB repair pathways are reviewed in this article. The strategy and application in cancer therapy are also discussed based on the advancement of inhibitors targeted DSB damage response and repair proteins.
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Affiliation(s)
- Jinpeng Tan
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Xingyao Sun
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Hongling Zhao
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Hua Guan
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Shanshan Gao
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
| | - Ping‐Kun Zhou
- Hengyang Medical CollegeUniversity of South ChinaHengyangHunan ProvinceChina
- Department of Radiation BiologyBeijing Key Laboratory for RadiobiologyBeijing Institute of Radiation MedicineBeijingChina
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3
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Wang L, Xue Y, Yang S, Bo T, Xu J, Wang W. Mismatch Repair Protein Msh2 Is Necessary for Macronuclear Stability and Micronuclear Division in Tetrahymena thermophila. Int J Mol Sci 2023; 24:10559. [PMID: 37445734 DOI: 10.3390/ijms241310559] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Mismatch repair (MMR) is a conserved mechanism that is primarily responsible for the repair of DNA mismatches during DNA replication. Msh2 forms MutS heterodimer complexes that initiate the MMR in eukaryotes. The function of Msh2 is less clear under different chromatin structures. Tetrahymena thermophila contains a transcriptionally active macronucleus (MAC) and a transcriptionally silent micronucleus (MIC) in the same cytoplasm. Msh2 is localized in the MAC and MIC during vegetative growth. Msh2 is localized in the perinuclear region around the MIC and forms a spindle-like structure as the MIC divides. During the early conjugation stage, Msh2 is localized in the MIC and disappears from the parental MAC. Msh2 is localized in the new MAC and new MIC during the late conjugation stage. Msh2 also forms a spindle-like structure with a meiotic MIC and mitotic gametic nucleus. MSH2 knockdown inhibits the division of MAC and MIC during vegetative growth and affects cellular proliferation. MSH2 knockdown mutants are sensitive to cisplatin treatment. MSH2 knockdown also affects micronuclear meiosis and gametogenesis during sexual development. Furthermore, Msh2 interacts with MMR-dependent and MMR-independent factors. Therefore, Msh2 is necessary for macronuclear stability, as well as micronuclear mitosis and meiosis in Tetrahymena.
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Affiliation(s)
- Lin Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Yuhuan Xue
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Sitong Yang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
| | - Tao Bo
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
- Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China
| | - Jing Xu
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Wei Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
- Shanxi Key Laboratory of Biotechnology, Taiyuan 030006, China
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4
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Tian M, Cai X, Liu Y, Liucong M, Howard-Till R. A practical reference for studying meiosis in the model ciliate Tetrahymena thermophila. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:595-608. [PMID: 37078080 PMCID: PMC10077211 DOI: 10.1007/s42995-022-00149-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 09/28/2022] [Indexed: 05/03/2023]
Abstract
Meiosis is a critical cell division program that produces haploid gametes for sexual reproduction. Abnormalities in meiosis are often causes of infertility and birth defects (e.g., Down syndrome). Most organisms use a highly specialized zipper-like protein complex, the synaptonemal complex (SC), to guide and stabilize pairing of homologous chromosomes in meiosis. Although the SC is critical for meiosis in many eukaryotes, there are organisms that perform meiosis without a functional SC. However, such SC-less meiosis is poorly characterized. To understand the features of SC-less meiosis and its adaptive significance, the ciliated protozoan Tetrahymena was selected as a model. Meiosis research in Tetrahymena has revealed intriguing aspects of the regulatory programs utilized in its SC-less meiosis, yet additional efforts are needed for obtaining an in-depth comprehension of mechanisms that are associated with the absence of SC. Here, aiming at promoting a wider application of Tetrahymena for meiosis research, we introduce basic concepts and core techniques for studying meiosis in Tetrahymena and then suggest future directions for expanding the current Tetrahymena meiosis research toolbox. These methodologies could be adopted for dissecting meiosis in poorly characterized ciliates that might reveal novel features. Such data will hopefully provide insights into the function of the SC and the evolution of meiosis from a unique perspective. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00149-8.
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Affiliation(s)
- Miao Tian
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
- Institute of Human Genetics, CNRS, University of Montpellier, 34090 Montpellier, France
| | - Xia Cai
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Yujie Liu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Mingmei Liucong
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
| | - Rachel Howard-Till
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA USA
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5
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Zhang J, Tian M, Chen K, Yan G, Xiong J, Miao W. Zfp1, a Cys2His2 zinc finger protein is required for meiosis initiation in Tetrahymena thermophila. Cell Cycle 2022; 21:1422-1433. [PMID: 35293272 PMCID: PMC9345619 DOI: 10.1080/15384101.2022.2053449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Meiosis is an important and highly conserved process that occurs during eukaryotic sexual reproduction. Diverse mechanisms are responsible for meiosis initiation among eukaryotes, and transcription factors have been established to have an important role in many species. However, the specific function of transcription factors in initiating meiosis in ciliates is unknown. Here we show that a putative Cys2His2 zinc finger-containing transcription factor encoded by the ZFP1 gene is specifically expressed during sexual reproduction in Tetrahymena thermophila. Meiosis is not initiated in the cells lacking ZFP1. Transcriptome sequencing analyses reveal that Zfp1 is required for the expression of many meiosis-specific genes. Our results indicate that Zfp1 could be a transcriptional activator required for meiosis initiation in T. thermophila.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Miao Tian
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Kai Chen
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Guanxiong Yan
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, Shanghai, China
| | - Jie Xiong
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Wei Miao
- Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China.,CAS Center for Excellence in Animal Evolution and Genetics, Kunming, Yunnan, China
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6
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Tian M, Mochizuki K, Loidl J. Arrested crossover precursor structures form stable homologous bonds in a Tetrahymena meiotic mutant. PLoS One 2022; 17:e0263691. [PMID: 35171923 PMCID: PMC8849441 DOI: 10.1371/journal.pone.0263691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 11/18/2022] Open
Abstract
Meiotic DNA double-strand breaks produce reciprocally exchanged DNA strands, which mature into chiasmata that hold homologous chromosomes together as bivalents. These bivalents are subsequently separated in the first meiotic division. In a mutant lacking the newly identified Tetrahymena gene APRO1 (Anaphase promoting 1), meiosis is arrested by the end of prophase. Mature chiasmata are not formed but bivalents are connected via a molecular precursor structure. In-depth analysis of this arrested intermediate structure may help to elucidate the noncanonical molecular recombination pathway in Tetrahymena.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | - Josef Loidl
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- * E-mail:
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7
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Abstract
The presence of meiosis, which is a conserved component of sexual reproduction, across organisms from all eukaryotic kingdoms, strongly argues that sex is a primordial feature of eukaryotes. However, extant meiotic structures and processes can vary considerably between organisms. The ciliated protist Tetrahymena thermophila, which diverged from animals, plants, and fungi early in evolution, provides one example of a rather unconventional meiosis. Tetrahymena has a simpler meiosis compared with most other organisms: It lacks both a synaptonemal complex (SC) and specialized meiotic machinery for chromosome cohesion and has a reduced capacity to regulate meiotic recombination. Despite this, it also features several unique mechanisms, including elongation of the nucleus to twice the cell length to promote homologous pairing and prevent recombination between sister chromatids. Comparison of the meiotic programs of Tetrahymena and higher multicellular organisms may reveal how extant meiosis evolved from proto-meiosis.
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Affiliation(s)
- Josef Loidl
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- * E-mail:
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8
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Xu Z, Zhang J, Cheng X, Tang Y, Gong Z, Gu M, Yu H. COM1, a factor of alternative non-homologous end joining, lagging behind the classic non-homologous end joining pathway in rice somatic cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:140-153. [PMID: 32022972 DOI: 10.1111/tpj.14715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 01/15/2020] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
The role of rice (Oryza sativa) COM1 in meiotic homologous recombination (HR) is well understood, but its part in somatic double-stranded break (DSB) repair remains unclear. Here, we show that for rice plants COM1 conferred tolerance against DNA damage caused by the chemicals bleomycin and mitomycin C, while the COM1 mutation did not compromise HR efficiencies and HR factor (RAD51 and RAD51 paralogues) localization to irradiation-induced DSBs. Similar retarded growth at the post-germination stage was observed in the com1-2 mre11 double mutant and the mre11 single mutant, while combined mutations in COM1 with the HR pathway gene (RAD51C) or classic non-homologous end joining (NHEJ) pathway genes (KU70, KU80, and LIG4) caused more phenotypic defects. In response to γ-irradiation, COM1 was loaded normally onto DSBs in the ku70 mutant, but could not be properly loaded in the MRE11RNAi plant and in the wortmannin-treated wild-type plant. Under non-irradiated conditions, more DSB sites were occupied by factors (MRE11, COM1, and LIG4) than RAD51 paralogues (RAD51B, RAD51C, and XRCC3) in the nucleus of wild-type; protein loading of COM1 and XRCC3 was increased in the ku70 mutant. Therefore, quite differently to its role for HR in meiocytes, rice COM1 specifically acts in an alternative NHEJ pathway in somatic cells, based on the Mre11-Rad50-Nbs1 (MRN) complex and facilitated by PI3K-like kinases. NHEJ factors, not HR factors, preferentially load onto endogenous DSBs, with KU70 restricting DSB localization of COM1 and XRCC3 in plant somatic cells.
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Affiliation(s)
- Zhan Xu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032, China
| | - Jianxiang Zhang
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Xinjie Cheng
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Yujie Tang
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zhiyun Gong
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Minghong Gu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Hengxiu Yu
- Key Laboratory of Plant Functional Genomics of Ministry of Education/Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
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9
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Xu WH, Wang J, Sheng HY, Qu YY, Wang HK, Zhu Y, Shi GH, Zhang HL, Ye DW. Prognostic implication and functional annotations of Rad50 expression in patients with prostate cancer. J Cell Biochem 2020; 121:3124-3134. [PMID: 31886567 DOI: 10.1002/jcb.29580] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 12/09/2019] [Indexed: 12/24/2022]
Abstract
Increasing evidence has shown that Rad50, a protein involved in the DNA damage repair process, significantly correlated with tumor prognosis. This study focused on Rad50 expression in tumor samples and its prognostic value for patients with prostate cancer (PCa). In this study, significantly elevated Rad50 expression in PCa tissues compared to normal tissues (P < .01). Five independent Oncomine databases validated significant differential expression of Rad50 (P < .001). Hence, 80 patients with PCa from Fudan University Shanghai Cancer Center (FUSCC) and 351 patients with PCa with available protein expression data from The Cancer Genome Atlas (TCGA) were included to investigate the survival benefit. Univariate and multivariate Cox regression analyses were performed to investigate the significance of clinicopathological factors on disease-free survival (DFS) and overall survival (OS). Kaplan-Meier analysis indicated that elevated Rad50 protein expression levels significantly correlated with unfavorable DFS (P = .005) in the FUSCC cohort and poorer OS (P = .04) in TCGA cohort. Furthermore, coregulation analysis of proteins indicated that 76 coregulated proteins were associated with Rad50, while 11 most highly involved hub proteins, including Rad50, MRE11A, DUT, POLR3A, MCM3AP, RECQL, PNPT1, RANBP3, DDX1, SNRPB, and UGN, were significantly coregulated in the protein-protein interaction network. Functional enrichment analysis consecutively indicated significant functions and signaling pathways including DNA replication, spliceosome, DNA geometric change, homologous recombination, and G2M checkpoint. This study first reveals that elevated Rad50 expression is significantly associated with aggressive progression and poor survival for patients with PCa. Together, these data suggest that Rad50 may act as an oncoprotein, guide the molecular diagnosis, and may shed light on novel individual therapeutic strategies for progressive PCa patients.
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Affiliation(s)
- Wen-Hao Xu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jun Wang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hao-Yue Sheng
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yuan-Yuan Qu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hong-Kai Wang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yu Zhu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Guo-Hai Shi
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hai-Liang Zhang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Ding-Wei Ye
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
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10
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Tian M, Loidl J. An MCM family protein promotes interhomolog recombination by preventing precocious intersister repair of meiotic DSBs. PLoS Genet 2019; 15:e1008514. [PMID: 31815942 PMCID: PMC6922451 DOI: 10.1371/journal.pgen.1008514] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/19/2019] [Accepted: 11/11/2019] [Indexed: 12/02/2022] Open
Abstract
Recombinational repair of meiotic DNA double-strand breaks (DSBs) uses the homologous chromosome as a template, although the sister chromatid offers itself as a spatially more convenient substrate. In many organisms, this choice is reinforced by the recombination protein Dmc1. In Tetrahymena, the repair of DSBs, which are formed early in prophase, is postponed to late prophase when homologous chromosomes and sister chromatids become juxtaposed owing to tight parallel packing in the thread-shaped nucleus, and thus become equally suitable for use as repair templates. The delay in DSB repair is achieved by rejection of the invading strand by the Sgs1 helicase in early meiotic prophase. In the absence of Mcmd1, a meiosis-specific minichromosome maintenance (MCM)-like protein (and its partner Pamd1), Dmc1 is prematurely lost from chromatin and DNA synthesis (as monitored by BrdU incorporation) takes place in early prophase. In mcmd1Δ and pamd1Δ mutants, only a few crossovers are formed. In a mcmd1Δ hop2Δ double mutant, normal timing of Dmc1 loss and DNA synthesis is restored. Because Tetrahymena Hop2 is believed to enable homologous strand invasion, we conclude that Dmc1 loss in the absence of Mcmd1 affects only post-invasion recombination intermediates. Therefore, we propose that the Dmc1 nucleofilament becomes dismantled immediately after forming a heteroduplex with a template strand. As a consequence, repair synthesis and D-loop extension starts in early prophase intermediates and prevents strand rejection before the completion of homologous pairing. In this case, DSB repair may primarily use the sister chromatid. We conclude that Mcmd1‒Pamd1 protects the Dmc1 nucleofilament from premature dismantling, thereby suppressing precocious repair synthesis and excessive intersister strand exchange at the cost of homologous recombination. Minichromosome maintenance (MCM) proteins are mainly known for their involvement in DNA replication. However, distant members of this protein family have recently been shown to promote interhomolog over intersister recombination in meiosis. They achieve this by enforcing or stabilizing the invasion of a double-stranded DNA by a filament consisting of a homologous single-stranded DNA molecule coated with a strand exchange protein. This interaction then would lead to the exchange of DNA strands and, ultimately, crossing over. Here, we study a member of the MCM protein family in the protist Tetrahymena thermophila. Meiosis in this organism has several unusual features: A synaptonemal complex is not formed, and homologous prealignment occurs during the close parallel arrangement of chromosomes in the extremely elongated, threadlike meiotic prophase nucleus. This noncanonical pairing has come along with altered mechanisms for recombination partner choice. Thus, we find that the Tetrahymena meiotic MCM protein promotes crossovers in an unprecedented way: It suppresses the formation of recombination intermediates between sister DNA molecules early in meiosis, thereby increasing the chance of competing interhomolog recombination events. Thus, members of the same protein family have been harnessed by different organisms to achieve the same result via completely different mechanisms.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- * E-mail:
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11
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Tian M, Mochizuki K, Loidl J. Non-coding RNA Transcription in Tetrahymena Meiotic Nuclei Requires Dedicated Mediator Complex-Associated Proteins. Curr Biol 2019; 29:2359-2370.e5. [PMID: 31280995 DOI: 10.1016/j.cub.2019.05.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/24/2019] [Accepted: 05/15/2019] [Indexed: 12/22/2022]
Abstract
To preserve genome integrity, eukaryotic cells use small RNA-directed mechanisms to repress transposable elements (TEs). Paradoxically, in order to silence TEs, precursors of the small RNAs must be transcribed from TEs. However, it is still poorly understood how these precursors are transcribed from TEs under silenced conditions. In the otherwise transcriptionally silent germline micronucleus (MIC) of Tetrahymena, a burst of non-coding RNA (ncRNA) transcription occurs during meiosis. The transcripts are processed into small RNAs that serve to identify TE-related sequences for elimination. The Mediator complex (Med) has an evolutionarily conserved role for transcription by bridging gene-specific transcription factors and RNA polymerase II. Here, we report that three Med-associated factors, Emit1, Emit2, and Rib1, are required for the biogenesis of small ncRNAs. Med localizes to the MIC only during meiosis, and both Med localization and MIC ncRNA transcription require Emit1 and Emit2. In the MIC, Med occupies TE-rich pericentromeric and telomeric regions in a Rib1-dependent manner. Rib1 is dispensable for ncRNA transcription but is required for the accumulation of double-stranded ncRNAs. Nuclear and sub-nuclear localization of the three Med-associated proteins is interdependent. Hence, Emit1 and Emit2 act coordinately to import Med into the MIC, and Rib1 recruits Med to specific chromosomal locations to quantitatively or qualitatively promote the biogenesis of functional ncRNA. Our results underscore that the transcription machinery can be regulated by a set of specialized Med-associated proteins to temporally transcribe TE-related sequences from a silent genome for small RNA biogenesis and genome defense.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria.
| | - Kazufumi Mochizuki
- Institute of Human Genetics (IGH), CNRS, University of Montpellier, 34090 Montpellier, France
| | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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12
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Tian M, Loidl J. A chromatin-associated protein required for inducing and limiting meiotic DNA double-strand break formation. Nucleic Acids Res 2019; 46:11822-11834. [PMID: 30357385 PMCID: PMC6294514 DOI: 10.1093/nar/gky968] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/05/2018] [Indexed: 11/13/2022] Open
Abstract
Programmed DNA double-strand breaks (DSBs) are required for meiotic recombination, but the number is strictly controlled because they are potentially harmful. Here we report a novel protein, Pars11, which is required for Spo11-dependent DSB formation in the protist Tetrahymena. Pars11 localizes to chromatin early in meiotic prophase in a Spo11-independent manner and is removed before the end of prophase. Pars11 removal depends on DSB formation and ATR-dependent phosphorylation. In the absence of the DNA damage sensor kinase ATR, Pars11 is retained on chromatin and excess DSBs are generated. Similar levels of Pars11 persistence and DSB overproduction occur in a non-phosphorylatable pars11 mutant. We conclude that Pars11 supports DSB formation by Spo11 until enough DSBs are formed; thereafter, DSB production stops in response to ATR-dependent degradation of Pars11 or its removal from chromatin. A similar DSB control mechanism involving a Rec114-Tel1/ATM-dependent negative feedback loop regulates DSB formation in budding yeast. However, there is no detectable sequence homology between Pars11 and Rec114, and DSB numbers are more tightly controlled by Pars11 than by Rec114. The discovery of this mechanism for DSB regulation in the evolutionarily distant protist and fungal lineages suggests that it is conserved across eukaryotes.
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Affiliation(s)
- Miao Tian
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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13
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Wang J, Xu WH, Wei Y, Zhu Y, Qin XJ, Zhang HL, Ye DW. Elevated MRE11 expression associated with progression and poor outcome in prostate cancer. J Cancer 2019; 10:4333-4340. [PMID: 31413753 PMCID: PMC6691708 DOI: 10.7150/jca.31454] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/06/2019] [Indexed: 01/14/2023] Open
Abstract
Objective: Growing evidence has proved that MRE11, a protein underpinned to be involved in DNA double-strand break (DSB) repair process, is correlated with cancer outcomes. However, its role in prostate cancer (PCa) remains unclear. This study aimed to investigate the expression of MRE11 in tumor tissue and defining its value in predicting prognosis of PCa patients. Methods: A total of 578 patients from two cohorts were enrolled in this study. Distribution of categorical clinical-pathological data together with levels of MRE11 expression was compared with χ2-test in a contingency table. Immunohistochemical (IHC) staining and evaluation was detected from 78 paired PCa and adjacent normal tissues. Partial likelihood test from univariate and multivariate Cox regression analysis was developed to address the influence of independent factors on disease-free survival (DFS) and overall survival (OS) in two cohorts. The Kaplan-Meier method and log-rank test were performed to assess the survival benefits between discrete levels. Set Enrichment Analysis (GSEA) was performed to select related genes and pathways from The Cancer Genome Atlas (TCGA) database. Results: In the current study, we demonstrated that MRE11 was highly expressed in PCa compared with normal tissues (P=0.011). In addition, in the TCGA cohort, the median DFS in patients with IHC positive and negative MRE11 expression levels was 24.5 and 30.6 months, and median OS was 28.7 and 33.0 months, respectively. In FUSCC cohort, median DFS in patients with IHC positive and negative MRE11 expression was 28.0 and 35.6 months. Furthermore, survival curves suggested that PCa patients with elevated MRE11 expression levels showed poorer OS (P=0.019) in TCGA cohort and poor DFS (P=0.047) in FUSCC cohort. Conclusion: In conclusion, our study reveals that elevated MRE11 expression is significantly correlated with cancer progression and poor survival in PCa patients. These data suggest that MRE11 may act as an oncoprotein and a promising prognostic marker for PCa patients.
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Affiliation(s)
- Jun Wang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Wen-Hao Xu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Yu Wei
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Yao Zhu
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Xiao-Jian Qin
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Hai-Liang Zhang
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
| | - Ding-Wei Ye
- Department of Urology, Fudan University Shanghai Cancer Center, Shanghai 200032.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 20032, P.R. China
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14
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Aksoz M, Albayrak E, Aslan GS, Turan RD, Alyazici LY, Siyah P, Tuysuz EC, Canikyan S, Yucel D, Meric N, Gulbas Z, Sahin F, Kocabas F. c-Myc Inhibitor 10074-G5 Induces Murine and Human Hematopoietic Stem and Progenitor Cell Expansion and HDR Modulator Rad51 Expression. Curr Cancer Drug Targets 2019; 19:479-494. [DOI: 10.2174/1568009618666180905100608] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 04/24/2018] [Accepted: 08/25/2018] [Indexed: 12/29/2022]
Abstract
Background:c-Myc plays a major role in the maintenance of glycolytic metabolism and hematopoietic stem cell (HSC) quiescence.Objective:Targeting modulators of HSC quiescence and metabolism could lead to HSC cell cycle entry with concomitant expansion.Methods and Results:Here we show that c-Myc inhibitor 10074-G5 treatment leads to 2-fold increase in murine LSKCD34low HSC compartment post 7 days. In addition, c-Myc inhibition increases CD34+ and CD133+ human HSC number. c-Myc inhibition leads to downregulation of glycolytic and cyclindependent kinase inhibitor (CDKI) gene expression ex vivo and in vivo. In addition, c-Myc inhibition upregulates major HDR modulator Rad51 expression in hematopoietic cells. Besides, c-Myc inhibition does not alter proliferation kinetics of endothelial cells, fibroblasts or adipose-derived mesenchymal stem cells, however, it limits bone marrow derived mesenchymal stem cell proliferation. We further demonstrate that a cocktail of c-Myc inhibitor 10074-G5 along with tauroursodeoxycholic acid (TUDCA) and i-NOS inhibitor L-NIL provides a robust HSC maintenance and expansion ex vivo as evident by induction of all stem cell antigens analyzed. Intriguingly, the cocktail of c-Myc inhibitor 10074-G5, TUDCA and L-NIL improves HDR related gene expression.Conclusion:These findings provide tools to improve ex vivo HSC maintenance and expansion, autologous HSC transplantation and gene editing through modulation of HSC glycolytic and HDR pathways.
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Affiliation(s)
- Merve Aksoz
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Esra Albayrak
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Galip Servet Aslan
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Raife Dilek Turan
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Lamia Yazgi Alyazici
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Pınar Siyah
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Emre Can Tuysuz
- Biotechnology Program, Graduate School of Natural and Applied Sciences, Yeditepe University, 34755, Istanbul, Turkey
| | - Serli Canikyan
- Onkim Stem Cell Technologies, Istanbul Technical University - KOSGEB, Istanbul, Turkey
| | - Dogacan Yucel
- Faculty of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Neslihan Meric
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Zafer Gulbas
- Bone Marrow Transplantation Center, Anadolu Medical Center, Kocaeli, Turkey
| | - Fikrettin Sahin
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
| | - Fatih Kocabas
- Regenerative Biology Research Laboratory, Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Istanbul, Turkey
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15
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Godau J, Ferretti LP, Trenner A, Dubois E, von Aesch C, Marmignon A, Simon L, Kapusta A, Guérois R, Bétermier M, Sartori AA. Identification of a miniature Sae2/Ctp1/CtIP ortholog from Paramecium tetraurelia required for sexual reproduction and DNA double-strand break repair. DNA Repair (Amst) 2019; 77:96-108. [DOI: 10.1016/j.dnarep.2019.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/28/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022]
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16
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Zhang J, Yan G, Tian M, Ma Y, Xiong J, Miao W. A DP-like transcription factor protein interacts with E2fl1 to regulate meiosis in Tetrahymena thermophila. Cell Cycle 2018; 17:634-642. [PMID: 29417875 DOI: 10.1080/15384101.2018.1431595] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Evolutionarily conserved E2F family transcription factors regulate the cell cycle via controlling gene expression in a wide range of eukaryotes. We previously demonstrated that the meiosis-specific transcription factor E2fl1 had an important role in meiosis in the model ciliate Tetrahymena thermophila. Here, we report that expression of another E2F family transcription factor gene DPL2 correlates highly with that of E2FL1. Similar to e2fl1Δ cells, dpl2Δ cells undergo meiotic arrest prior to anaphase I, with the five chromosomes adopting an abnormal tandem arrangement. Immunofluorescence staining and immunoprecipitation experiments demonstrate that Dpl2 and E2fl1 form a complex during meiosis. We previously identified several meiotic regulatory proteins in T. thermophila. Cyc2 and Tcdk3 may cooperate to initiate meiosis and Cyc17 is essential for initiating meiotic anaphase. We investigate the relationship of these regulators with Dpl2 and E2fl1, and then construct a meiotic regulatory network by measuring changes in meiotic genes expression in knockout cells. We conclude that the E2fl1/Dpl2 complex plays a central role in meiosis in T. thermophila.
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Affiliation(s)
- Jing Zhang
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Guanxiong Yan
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Miao Tian
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China
| | - Yang Ma
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Jie Xiong
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China
| | - Wei Miao
- a Key Laboratory of Aquatic Biodiversity and Conservation , Institute of Hydrobiology , Chinese Academy of Sciences , Wuhan , People's Republic of China
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17
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Howard-Till R, Loidl J. Condensins promote chromosome individualization and segregation during mitosis, meiosis, and amitosis in Tetrahymena thermophila. Mol Biol Cell 2017; 29:466-478. [PMID: 29237819 PMCID: PMC6014175 DOI: 10.1091/mbc.e17-07-0451] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/27/2017] [Accepted: 12/07/2017] [Indexed: 11/11/2022] Open
Abstract
Condensin is a protein complex with diverse functions in chromatin packaging and chromosome condensation and segregation. We studied condensin in the evolutionarily distant protist model Tetrahymena, which features noncanonical nuclear organization and divisions. In Tetrahymena, the germline and soma are partitioned into two different nuclei within a single cell. Consistent with their functional specializations in sexual reproduction and gene expression, condensins of the germline nucleus and the polyploid somatic nucleus are composed of different subunits. Mitosis and meiosis of the germline nucleus and amitotic division of the somatic nucleus are all dependent on condensins. In condensin-depleted cells, a chromosome condensation defect was most striking at meiotic metaphase, when Tetrahymena chromosomes are normally most densely packaged. Live imaging of meiotic divisions in condensin-depleted cells showed repeated nuclear stretching and contraction as the chromosomes failed to separate. Condensin depletion also fundamentally altered chromosome arrangement in the polyploid somatic nucleus: multiple copies of homologous chromosomes tended to cluster, consistent with a previous model of condensin suppressing default somatic pairing. We propose that failure to form discrete chromosome territories is the common cause of the defects observed in the absence of condensins.
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Affiliation(s)
- Rachel Howard-Till
- Department of Chromosome Biology, University of Vienna, 1190 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, 1190 Vienna, Austria
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18
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BIME2, a novel gene required for interhomolog meiotic recombination in the protist model organism Tetrahymena. Chromosome Res 2017; 25:291-298. [PMID: 28803330 PMCID: PMC5662671 DOI: 10.1007/s10577-017-9563-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/23/2022]
Abstract
Meiotic recombination is initiated by DNA double-strand breaks (DSBs). Most DSBs are converted into nonreciprocal exchanges (gene conversions) or crossovers (COs) between sister chromatids. Only a minority of DSBs are processed toward interhomolog COs, the precursors of the chiasmata that connect homologous chromosomes. Dmc1, the meiosis-specific paralog of the universal recombination protein Rad51, is required for interhomolog COs; in its absence, univalents are primarily formed. Here, we report a ciliate-specific novel meiotic gene, BIME2, which also promotes interhomolog crossing over. In the bime2Δ mutant, DSBs are formed and repaired normally, but bivalent formation is strongly reduced. Bime2 protein forms foci on chromatin during meiotic prophase, and chromatin localization of Bime2 and Dmc1 is largely interdependent. Bime2 distantly resembles budding yeast Rdh54/Tid1 and the vertebrate Rad54B helicases and may have similar functions in promoting or stabilizing Dmc1 nucleoprotein filaments.
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19
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Shodhan A, Kataoka K, Mochizuki K, Novatchkova M, Loidl J. A Zip3-like protein plays a role in crossover formation in the SC-less meiosis of the protist Tetrahymena. Mol Biol Cell 2017; 28:825-833. [PMID: 28100637 PMCID: PMC5349789 DOI: 10.1091/mbc.e16-09-0678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/21/2016] [Accepted: 01/09/2017] [Indexed: 11/11/2022] Open
Abstract
When programmed meiotic DNA double-strand breaks (DSBs) undergo recombinational repair, genetic crossovers (COs) may be formed. A certain level of this is required for the faithful segregation of chromosomes, but the majority of DSBs are processed toward a safer alternative, namely noncrossovers (NCOs), via nonreciprocal DNA exchange. At the crossroads between these two DSB fates is the Msh4-Msh5 (MutSγ) complex, which stabilizes CO-destined recombination intermediates and members of the Zip3/RNF212 family of RING finger proteins, which in turn stabilize MutSγ. These proteins function in the context of the synaptonemal complex (SC) and mainly act on SC-dependent COs. Here we show that in the SC-less ciliate Tetrahymena, Zhp3 (a protein distantly related to Zip3/RNF212), together with MutSγ, is responsible for the majority of COs. This activity of Zhp3 suggests an evolutionarily conserved SC-independent strategy for balancing CO:NCO ratios. Moreover, we report a novel meiosis-specific protein, Sa15, as an interacting partner of Zhp3. Sa15 forms linear structures in meiotic prophase nuclei to which Zhp3 localizes. Sa15 is required for a wild-type level of CO formation. Its linear organization suggests the existence of an underlying chromosomal axis that serves as a scaffold for Zhp3 and other recombination proteins.
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Affiliation(s)
- Anura Shodhan
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Kensuke Kataoka
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Kazufumi Mochizuki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Maria Novatchkova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
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20
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Zhang J, Tian M, Yan GX, Shodhan A, Miao W. E2fl1 is a meiosis-specific transcription factor in the protist Tetrahymena thermophila. Cell Cycle 2016; 16:123-135. [PMID: 27892792 DOI: 10.1080/15384101.2016.1259779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Members of the E2F family of transcription factors have been reported to regulate the expression of genes involved in cell cycle control, DNA replication, and DNA repair in multicellular eukaryotes. Here, E2FL1, a meiosis-specific E2F transcription factor gene, was identified in the model ciliate Tetrahymena thermophila. Loss of this gene resulted in meiotic arrest prior to anaphase I. The cytological experiments revealed that the meiotic homologous pairing was not affected in the absence of E2FL1, but the paired homologous chromosomes did not separate and assumed a peculiar tandem arrangement. This is the first time that an E2F family member has been shown to regulate meiotic events. Moreover, BrdU incorporation showed that DSB processing during meiosis was abnormal upon the deletion of E2FL1. Transcriptome sequencing analysis revealed that E2FL1 knockout decreased the expression of genes involved in DNA replication and DNA repair in T. thermophila, suggesting that the function of E2F is highly conserved in eukaryotes. In addition, E2FL1 deletion inhibited the expression of related homologous chromosome segregation genes in T. thermophila. The result may explain the meiotic arrest phenotype at anaphase I. Finally, by searching for E2F DNA-binding motifs in the entire T. thermophila genome, we identified 714 genes containing at least one E2F DNA-binding motif; of these, 235 downregulated represent putative E2FL1 target genes.
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Affiliation(s)
- Jing Zhang
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Miao Tian
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,c Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Guan-Xiong Yan
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Anura Shodhan
- c Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Wei Miao
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China
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21
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Yan GX, Zhang J, Shodhan A, Tian M, Miao W. Cdk3, a conjugation-specific cyclin-dependent kinase, is essential for the initiation of meiosis in Tetrahymena thermophila. Cell Cycle 2016; 15:2506-14. [PMID: 27420775 DOI: 10.1080/15384101.2016.1207838] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Meiosis is an important process in sexual reproduction. Meiosis initiation has been found to be highly diverse among species. In yeast, it has been established that cyclin-dependent kinases (Cdks) and cyclins are essential components in the meiosis initiation pathway. In this study, we identified 4 Cdks in the model ciliate, Tetrahymena thermophila, and we found one of them, Cdk3, which is specifically expressed during early conjugation, to be essential for meiosis initiation. Cdk3 deletion led to arrest at the pair formation stage of conjugation. We then confirmed that Cdk3 acts upstream of double-strand break (DSB) formation. Moreover, we detected that Cdk3 is necessary for the expression of many genes involved in early meiotic events. Through proteomic quantification of phosphorylation, co-expression analysis and RNA-Seq analyses, we identified a conjugation-specific cyclin, Cyc2, which most likely partners with Cdk3 to initiate meiosis.
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Affiliation(s)
- Guan-Xiong Yan
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Jing Zhang
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Anura Shodhan
- c Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Miao Tian
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,c Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Wei Miao
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China
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22
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Yan GX, Dang H, Tian M, Zhang J, Shodhan A, Ning YZ, Xiong J, Miao W. Cyc17, a meiosis-specific cyclin, is essential for anaphase initiation and chromosome segregation in Tetrahymena thermophila. Cell Cycle 2016; 15:1855-64. [PMID: 27192402 DOI: 10.1080/15384101.2016.1188238] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although the role of cyclins in controlling nuclear division is well established, their function in ciliate meiosis remains unknown. In ciliates, the cyclin family has undergone massive expansion which suggests that diverse cell cycle systems exist, and this warrants further investigation. A screen for cyclins in the model ciliate Tetrahymena thermophila showed that there are 34 cyclins in this organism. Only 1 cyclin, Cyc17, contains the complete cyclin core and is specifically expressed during meiosis. Deletion of CYC17 led to meiotic arrest at the diakinesis-like metaphase I stage. Expression of genes involved in DNA metabolism and chromosome organization (chromatin remodeling and basic chromosomal structure) was repressed in cyc17 knockout matings. Further investigation suggested that Cyc17 is involved in regulating spindle pole attachment, and is thus essential for chromosome segregation at meiosis. These findings suggest a simple model in which chromosome segregation is influenced by Cyc17.
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Affiliation(s)
- Guan-Xiong Yan
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Huai Dang
- c College of Life Sciences, Northwest Normal University , Lanzhou , People's Republic of China
| | - Miao Tian
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,d Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Jing Zhang
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China.,b University of Chinese Academy of Sciences , Beijing , People's Republic of China
| | - Anura Shodhan
- d Department of Chromosome Biology and Max F. Perutz Laboratories , Center for Molecular Biology, University of Vienna , Vienna , Austria
| | - Ying-Zhi Ning
- c College of Life Sciences, Northwest Normal University , Lanzhou , People's Republic of China
| | - Jie Xiong
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China
| | - Wei Miao
- a Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences , Wuhan , People's Republic of China
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Loidl J, Lorenz A. DNA double-strand break formation and repair in Tetrahymena meiosis. Semin Cell Dev Biol 2016; 54:126-34. [PMID: 26899715 DOI: 10.1016/j.semcdb.2016.02.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/12/2016] [Indexed: 11/18/2022]
Abstract
The molecular details of meiotic recombination have been determined for a small number of model organisms. From these studies, a general picture has emerged that shows that most, if not all, recombination is initiated by a DNA double-strand break (DSB) that is repaired in a recombinogenic process using a homologous DNA strand as a template. However, the details of recombination vary between organisms, and it is unknown which variant is representative of evolutionarily primordial meiosis or most prevalent among eukaryotes. To answer these questions and to obtain a better understanding of the range of recombination processes among eukaryotes, it is important to study a variety of different organisms. Here, the ciliate Tetrahymena thermophila is introduced as a versatile meiotic model system, which has the additional bonus of having the largest phylogenetic distance to all of the eukaryotes studied to date. Studying this organism can contribute to our understanding of the conservation and diversification of meiotic recombination processes.
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Affiliation(s)
- Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
| | - Alexander Lorenz
- Institute of Medical Sciences (IMS), University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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Lukaszewicz A, Shodhan A, Loidl J. Exo1 and Mre11 execute meiotic DSB end resection in the protist Tetrahymena. DNA Repair (Amst) 2015; 35:137-43. [PMID: 26519827 DOI: 10.1016/j.dnarep.2015.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/26/2015] [Accepted: 08/26/2015] [Indexed: 01/09/2023]
Abstract
The resection of 5'-DNA ends at a double-strand break (DSB) is an essential step in recombinational repair, as it exposes 3' single-stranded DNA (ssDNA) tails for interaction with a repair template. In mitosis, Exo1 and Sgs1 have a conserved function in the formation of long ssDNA tails, whereas this step in the processing of programmed meiotic DSBs is less well-characterized across model organisms. In budding yeast, which has been most intensely studied in this respect, Exo1 is a major meiotic nuclease. In addition, it exerts a nuclease-independent function later in meiosis in the conversion of DNA joint molecules into ZMM-dependent crossovers. In order to gain insight into the diverse meiotic roles of Exo1, we investigated the effect of Exo1 deletion in the ciliated protist Tetrahymena. We found that Exo1 together with Mre11, but without the help of Sgs1, promotes meiotic DSB end resection. Resection is completely eliminated only if both Mre11 and Exo1 are missing. This is consistent with the yeast model where Mre11 promotes resection in the 3'-5' direction and Exo1 in the opposite 5'-3' direction. However, while the endonuclease activity of Mre11 is essential to create an entry site for exonucleases and hence to start resection in budding yeast, Tetrahymena Exo1 is able to create single-stranded DNA in the absence of Mre11. Excluding a possible contribution of the Mre11 cofactor Sae2 (Com1) as an autonomous endonuclease, we conclude that there exists another unknown nuclease that initiates DSB processing in Tetrahymena. Consistent with the absence of the ZMM crossover pathway in Tetrahymena, crossover formation is independent of Exo1.
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Affiliation(s)
- Agnieszka Lukaszewicz
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
| | - Anura Shodhan
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, A-1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
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A computational study of dsDNA pairs and vibrational resonance in separating water. SYSTEMS AND SYNTHETIC BIOLOGY 2015; 8:329-35. [PMID: 26396657 DOI: 10.1007/s11693-014-9157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 10/19/2014] [Accepted: 10/27/2014] [Indexed: 10/24/2022]
Abstract
This article investigates the relationship between molecular sequence and dependent interacting behavior of molecular segment pairs and secondly, sequence dependent, vibrational resonance in surrounding normal saline, protein-free water. The development of a molecular model to explore these systems phenomena, the results of several nanoscale molecular dynamics simulations, and analysis of behavior of interacting ΦX174 double-stranded DNA segment pair models in various configurations are presented. Fourier analysis revealed intriguing vibration frequencies within the solvent plane between the segments, while subsequent frequency domain transformation of the time domain waveforms revealed statistically significant resonating harmonic signals in the THz range.
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MR (Mre11-Rad50) complex in Giardia duodenalis: In vitro characterization and its response upon DNA damage. Biochimie 2015; 111:45-57. [DOI: 10.1016/j.biochi.2015.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 01/17/2015] [Indexed: 11/24/2022]
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Shodhan A, Lukaszewicz A, Novatchkova M, Loidl J. Msh4 and Msh5 function in SC-independent chiasma formation during the streamlined meiosis of Tetrahymena. Genetics 2014; 198:983-93. [PMID: 25217051 PMCID: PMC4224184 DOI: 10.1534/genetics.114.169698] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 09/06/2014] [Indexed: 11/25/2022] Open
Abstract
ZMM proteins have been defined in budding yeast as factors that are collectively involved in the formation of interfering crossovers (COs) and synaptonemal complexes (SCs), and they are a hallmark of the predominant meiotic recombination pathway of most organisms. In addition to this so-called class I CO pathway, a minority of crossovers are formed by a class II pathway, which involves the Mus81-Mms4 endonuclease complex. This is the only CO pathway in the SC-less meiosis of the fission yeast. ZMM proteins (including SC components) were always found to be co-occurring and hence have been regarded as functionally linked. Like the fission yeast, the protist Tetrahymena thermophila does not possess a SC, and its COs are dependent on Mus81-Mms4. Here we show that the ZMM proteins Msh4 and Msh5 are required for normal chiasma formation, and we propose that they have a pro-CO function outside a canonical class I pathway in Tetrahymena. Thus, the two-pathway model is not tenable as a general rule.
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Affiliation(s)
- Anura Shodhan
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
| | - Agnieszka Lukaszewicz
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
| | - Maria Novatchkova
- Research Institute of Molecular Pathology, A-130 Vienna, Austria IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, A-1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
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de Massy B. Initiation of meiotic recombination: how and where? Conservation and specificities among eukaryotes. Annu Rev Genet 2014; 47:563-99. [PMID: 24050176 DOI: 10.1146/annurev-genet-110711-155423] [Citation(s) in RCA: 243] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Meiotic recombination is essential for fertility in most sexually reproducing species. This process also creates new combinations of alleles and has important consequences for genome evolution. Meiotic recombination is initiated by the formation of DNA double-strand breaks (DSBs), which are repaired by homologous recombination. DSBs are catalyzed by the evolutionarily conserved SPO11 protein, assisted by several other factors. Some of them are absolutely required, whereas others are needed only for full levels of DSB formation and may participate in the regulation of DSB timing and frequency as well as the coordination between DSB formation and repair. The sites where DSBs occur are not randomly distributed in the genome, and remarkably distinct strategies have emerged to control their localization in different species. Here, I review the recent advances in the components required for DSB formation and localization in the various model organisms in which these studies have been performed.
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Affiliation(s)
- Bernard de Massy
- Institute of Human Genetics, Centre National de la Recherché Scientifique, UPR1142, 34396 Montpellier, France;
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Chi J, Mahé F, Loidl J, Logsdon J, Dunthorn M. Meiosis gene inventory of four ciliates reveals the prevalence of a synaptonemal complex-independent crossover pathway. Mol Biol Evol 2013; 31:660-72. [PMID: 24336924 DOI: 10.1093/molbev/mst258] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To establish which meiosis genes are present in ciliates, and to look for clues as to which recombination pathways may be treaded by them, four genomes were inventoried for 11 meiosis-specific and 40 meiosis-related genes. We found that the set of meiosis genes shared by Tetrahymena thermophila, Paramecium tetraurelia, Ichthyophthirius multifiliis, and Oxytricha trifallax is consistent with the prevalence of a Mus81-dependent class II crossover pathway that is considered secondary in most model eukaryotes. There is little evidence for a canonical class I crossover pathway that requires the formation of a synaptonemal complex (SC). This gene inventory suggests that meiotic processes in ciliates largely depend on mitotic repair proteins for executing meiotic recombination. We propose that class I crossovers and SCs were reduced sometime during the evolution of ciliates. Consistent with this reduction, we provide microscopic evidence for the presence only of degenerate SCs in Stylonychia mytilus. In addition, lower nonsynonymous to synonymous mutation rates of some of the meiosis genes suggest that, in contrast to most other nuclear genes analyzed so far, meiosis genes in ciliates are largely evolving at a slower rate than those genes in fungi and animals.
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Affiliation(s)
- Jingyun Chi
- Department of Ecology, University of Kaiserslautern, Kaiserslautern, Germany
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30
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Lukaszewicz A, Howard-Till RA, Loidl J. Mus81 nuclease and Sgs1 helicase are essential for meiotic recombination in a protist lacking a synaptonemal complex. Nucleic Acids Res 2013; 41:9296-309. [PMID: 23935123 PMCID: PMC3814389 DOI: 10.1093/nar/gkt703] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 11/18/2022] Open
Abstract
Mus81 resolvase and Sgs1 helicase have well-established roles in mitotic DNA repair. Moreover, Mus81 is part of a minor crossover (CO) pathway in the meiosis of budding yeast, plants and vertebrates. The major pathway depends on meiosis-specific synaptonemal complex (SC) formation, ZMM proteins and the MutLγ complex for CO-directed resolution of joint molecule (JM)-recombination intermediates. Sgs1 has also been implicated in this pathway, although it may mainly promote the non-CO outcome of meiotic repair. We show in Tetrahymena, that homologous chromosomes fail to separate and JMs accumulate in the absence of Mus81 or Sgs1, whereas deletion of the MutLγ-component Mlh1 does not affect meiotic divisions. Thus, our results are consistent with Mus81 being part of an essential, if not the predominant, CO pathway in Tetrahymena. Sgs1 may exert functions similar to those in other eukaryotes. However, we propose an additional role in supporting homologous CO formation by promoting homologous over intersister interactions. Tetrahymena shares the predominance of the Mus81 CO pathway with the fission yeast. We propose that in these two organisms, which independently lost the SC during evolution, the basal set of mitotic repair proteins is sufficient for executing meiotic recombination.
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Affiliation(s)
| | | | - Josef Loidl
- Department of Chromosome Biology, Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
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31
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Titus S, Li F, Stobezki R, Akula K, Unsal E, Jeong K, Dickler M, Robson M, Moy F, Goswami S, Oktay K. Impairment of BRCA1-related DNA double-strand break repair leads to ovarian aging in mice and humans. Sci Transl Med 2013; 5:172ra21. [PMID: 23408054 DOI: 10.1126/scitranslmed.3004925] [Citation(s) in RCA: 327] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The underlying mechanism behind age-induced wastage of the human ovarian follicle reserve is unknown. We identify impaired ATM (ataxia-telangiectasia mutated)-mediated DNA double-strand break (DSB) repair as a cause of aging in mouse and human oocytes. We show that DSBs accumulate in primordial follicles with age. In parallel, expression of key DNA DSB repair genes BRCA1, MRE11, Rad51, and ATM, but not BRCA2, declines in single mouse and human oocytes. In Brca1-deficient mice, reproductive capacity was impaired, primordial follicle counts were lower, and DSBs were increased in remaining follicles with age relative to wild-type mice. Furthermore, oocyte-specific knockdown of Brca1, MRE11, Rad51, and ATM expression increased DSBs and reduced survival, whereas Brca1 overexpression enhanced both parameters. Likewise, ovarian reserve was impaired in young women with germline BRCA1 mutations compared to controls as determined by serum concentrations of anti-Müllerian hormone. These data implicate DNA DSB repair efficiency as an important determinant of oocyte aging in women.
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Affiliation(s)
- Shiny Titus
- Institute for Reproductive Medicine and Fertility Preservation, and Laboratory of Molecular Reproduction, Department of Obstetrics and Gynecology, New York Medical College, Rye, NY 10580, USA
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Howard-Till RA, Lukaszewicz A, Novatchkova M, Loidl J. A single cohesin complex performs mitotic and meiotic functions in the protist tetrahymena. PLoS Genet 2013; 9:e1003418. [PMID: 23555314 PMCID: PMC3610610 DOI: 10.1371/journal.pgen.1003418] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 02/12/2013] [Indexed: 01/08/2023] Open
Abstract
The cohesion of sister chromatids in the interval between chromosome replication and anaphase is important for preventing the precocious separation, and hence nondisjunction, of chromatids. Cohesion is accomplished by a ring-shaped protein complex, cohesin; and its release at anaphase occurs when separase cleaves the complex's α-kleisin subunit. Cohesin has additional roles in facilitating DNA damage repair from the sister chromatid and in regulating gene expression. We tested the universality of the present model of cohesion by studying cohesin in the evolutionarily distant protist Tetrahymena thermophila. Localization of tagged cohesin components Smc1p and Rec8p (the α-kleisin) showed that cohesin is abundant in mitotic and meiotic nuclei. RNAi knockdown experiments demonstrated that cohesin is crucial for normal chromosome segregation and meiotic DSB repair. Unexpectedly, cohesin does not detach from chromosome arms in anaphase, yet chromosome segregation depends on the activity of separase (Esp1p). When Esp1p is depleted by RNAi, chromosomes become polytenic as they undergo multiple rounds of replication, but fail to separate. The cohesion of such bundles of numerous chromatids suggests that chromatids may be connected by factors in addition to topological linkage by cohesin rings. Although cohesin is not detected in transcriptionally active somatic nuclei, its loss causes a slight defect in their amitotic division. Notably, Tetrahymena uses a single version of α-kleisin for both mitosis and meiosis. Therefore, we propose that the differentiation of mitotic and meiotic cohesins found in most other model systems is not due to the need of a specialized meiotic cohesin, but due to additional roles of mitotic cohesin.
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Affiliation(s)
- Rachel A. Howard-Till
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Agnieszka Lukaszewicz
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Maria Novatchkova
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
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Ji J, Tang D, Wang K, Wang M, Che L, Li M, Cheng Z. The role of OsCOM1 in homologous chromosome synapsis and recombination in rice meiosis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:18-30. [PMID: 22507309 DOI: 10.1111/j.1365-313x.2012.05025.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
COM1/SAE2 is a highly conserved gene from yeast to higher eukaryotes. Its orthologs, known to cooperate with the MRX complex (Mre11/Rad50/Xrs2), are required for meiotic DNA double-strand break (DSB) ends resection and specific mitotic DSB repair events. Here, the rice (Oryza sativa, 2n = 2x = 24) COM1/SAE2 homolog was identified through positional cloning, termed OsCOM1. Four independent mutants of OsCOM1 were isolated and characterized. In Oscom1 mutants, synaptonemal complex (SC) formation, homologous pairing and recombination were severely inhibited, whereas aberrant non-homologous chromosome entanglements occurred constantly. Several key meiotic proteins, including ZEP1 and OsMER3, were not loaded normally onto chromosomes in Oscom1 mutants, whereas the localization of OsREC8, PAIR2 and PAIR3 seemed to be normal. Moreover, OsCOM1 was loaded normally onto meiotic chromosomes in Osrec8, zep1 and Osmer3 mutants, but could not be properly loaded in Osam1, pair2 and OsSPO11-1(RNAi) plants. These results provide direct evidence for the functions of OsCOM1 in promoting homologous synapsis and recombination in rice meiosis.
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Affiliation(s)
- Jianhui Ji
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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34
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Loidl J, Lukaszewicz A, Howard-Till RA, Koestler T. The Tetrahymena meiotic chromosome bouquet is organized by centromeres and promotes interhomolog recombination. J Cell Sci 2012; 125:5873-80. [PMID: 22976299 DOI: 10.1242/jcs.112664] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to form crossovers and to undergo reductional segregation during meiosis, homologous chromosomes must pair. In Tetrahymena, meiotic prophase nuclei elongate immensely, and, within the elongated nucleus, chromosomes are arranged with telomeres assembled at one pole and centromeres at the opposite pole. This organisation is an exaggerated form of the bouquet, a meiotic chromosome arrangement that is widely conserved among eukaryotes. We show that centromere function is crucial for the formation of Tetrahymena's stretched bouquet and, thereby, for homologue pairing. This finding adds to previous reports of the importance of centromeres in chromosome pairing in budding yeast and in Drosophila. Tetrahymena's bouquet is an ataxia telangiectasia- and RAD3-related (ATR)-dependent meiotic DNA damage response that is triggered by meiotic DNA double-strand breaks (DSBs), suggesting that the bouquet is needed for DSB repair. However, in the present study we show that although homologous pairing is impeded in the absence of the bouquet, DSB repair takes place nevertheless. Moreover, recombinational DSB repair, as monitored by bromodeoxyuridine incorporation, takes place only after exit from the bouquet stage. Therefore, we conclude that the bouquet is not required for DSB repair per se, but may be necessary for the alignment of homologous loci in order to promote homologous crossovers over alternative repair pathways.
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Affiliation(s)
- Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
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35
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Bonfils S, Rozalén AE, Smith GR, Moreno S, Martín-Castellanos C. Functional interactions of Rec24, the fission yeast ortholog of mouse Mei4, with the meiotic recombination-initiation complex. J Cell Sci 2011; 124:1328-38. [PMID: 21429938 PMCID: PMC3065387 DOI: 10.1242/jcs.079194] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2010] [Indexed: 11/20/2022] Open
Abstract
A physical connection between each pair of homologous chromosomes is crucial for reductional chromosome segregation during the first meiotic division and therefore for successful meiosis. Connection is provided by recombination (crossing over) initiated by programmed DNA double-strand breaks (DSBs). Although the topoisomerase-like protein Spo11 makes DSBs and is evolutionarily conserved, how Spo11 (Rec12 in fission yeast) is regulated to form DSBs at the proper time and place is poorly understood. Several additional (accessory) proteins for DSB formation have been inferred in different species from yeast to mice. Here, we show that Rec24 is a bona fide accessory protein in Schizosaccharomyces pombe. Rec24 is required genome-wide for crossing-over and is recruited to meiotic chromosomes during prophase in a Rec12-independent manner forming foci on linear elements (LinEs), structurally related to the synaptonemal complex of other eukaryotes. Stabilization of Rec24 on LinEs depends on another accessory protein, Rec7, with which Rec24 forms complexes in vivo. We propose that Rec24 marks LinE-associated recombination sites, that stabilization of its binding by Rec7 facilitates the loading or activation of Rec12, and that only stabilized complexes containing Rec24 and Rec7 promote DSB formation. Based on the recent report of Rec24 and Rec7 conservation, interaction between Rec24 and Rec7 might be widely conserved in DSB formation.
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Affiliation(s)
- Sandrine Bonfils
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Ana E. Rozalén
- Instituto de Biología Molecular y Celular del Cáncer, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Gerald R. Smith
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Sergio Moreno
- Instituto de Biología Molecular y Celular del Cáncer, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - Cristina Martín-Castellanos
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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Howard-Till RA, Lukaszewicz A, Loidl J. The recombinases Rad51 and Dmc1 play distinct roles in DNA break repair and recombination partner choice in the meiosis of Tetrahymena. PLoS Genet 2011; 7:e1001359. [PMID: 21483758 PMCID: PMC3069121 DOI: 10.1371/journal.pgen.1001359] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 03/01/2011] [Indexed: 11/18/2022] Open
Abstract
Repair of programmed DNA double-strand breaks (DSBs) by meiotic recombination relies on the generation of flanking 3' single-stranded DNA overhangs and their interaction with a homologous double-stranded DNA template. In various common model organisms, the ubiquitous strand exchange protein Rad51 and its meiosis-specific homologue Dmc1 have been implicated in the joint promotion of DNA-strand exchange at meiotic recombination sites. However, the division of labor between these two recombinases is still a puzzle. Using RNAi and gene-disruption experiments, we have studied their roles in meiotic recombination and chromosome pairing in the ciliated protist Tetrahymena as an evolutionarily distant meiotic model. Cytological and electrophoresis-based assays for DSBs revealed that, without Rad51p, DSBs were not repaired. However, in the absence of Dmc1p, efficient Rad51p-dependent repair took place, but crossing over was suppressed. Immunostaining and protein tagging demonstrated that only Dmc1p formed strong DSB-dependent foci on meiotic chromatin, whereas the distribution of Rad51p was diffuse within nuclei. This suggests that meiotic nucleoprotein filaments consist primarily of Dmc1p. Moreover, a proximity ligation assay confirmed that little if any Rad51p forms mixed nucleoprotein filaments with Dmc1p. Dmc1p focus formation was independent of the presence of Rad51p. The absence of Dmc1p did not result in compensatory assembly of Rad51p repair foci, and even artificial DNA damage by UV failed to induce Rad51p foci in meiotic nuclei, while it did so in somatic nuclei within one and the same cell. The observed interhomologue repair deficit in dmc1Δ meiosis is consistent with a requirement for Dmc1p in promoting the homologue as the preferred recombination partner. We propose that relatively short and/or transient Rad51p nucleoprotein filaments are sufficient for intrachromosomal recombination, whereas long nucleoprotein filaments consisting primarily of Dmc1p are required for interhomolog recombination.
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Affiliation(s)
- Rachel A. Howard-Till
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Agnieszka Lukaszewicz
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, Vienna, Austria
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37
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Edlinger B, Schlögelhofer P. Have a break: determinants of meiotic DNA double strand break (DSB) formation and processing in plants. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:1545-63. [PMID: 21220780 DOI: 10.1093/jxb/erq421] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Meiosis is an essential process for sexually reproducing organisms, leading to the formation of specialized generative cells. This review intends to highlight current knowledge of early events during meiosis derived from various model organisms, including plants. It will particularly focus on cis- and trans-requirements of meiotic DNA double strand break (DSB) formation, a hallmark event during meiosis and a prerequisite for recombination of genetic traits. Proteins involved in DSB formation in different organisms, emphasizing the known factors from plants, will be introduced and their functions outlined. Recent technical advances in DSB detection and meiotic recombination analysis will be reviewed, as these new tools now allow analysis of early meiotic recombination in plants with incredible accuracy. To anticipate future directions in plant meiosis research, unpublished results will be included wherever possible.
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Affiliation(s)
- Bernd Edlinger
- University of Vienna, Max F. Perutz Laboratories, Department of Chromosome Biology, Dr. Bohr-Gasse 1, Vienna, Austria
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38
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Kan F, Davidson MK, Wahls WP. Meiotic recombination protein Rec12: functional conservation, crossover homeostasis and early crossover/non-crossover decision. Nucleic Acids Res 2010; 39:1460-72. [PMID: 21030440 PMCID: PMC3045620 DOI: 10.1093/nar/gkq993] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In fission yeast and other eukaryotes, Rec12 (Spo11) is thought to catalyze the formation of dsDNA breaks (DSBs) that initiate homologous recombination in meiosis. Rec12 is orthologous to the catalytic subunit of topoisomerase VI (Top6A). Guided by the crystal structure of Top6A, we engineered the rec12 locus to encode Rec12 proteins each with a single amino acid substitution in a conserved residue. Of 21 substitutions, 10 significantly reduced or abolished meiotic DSBs, gene conversion, crossover recombination and the faithful segregation of chromosomes. Critical residues map within the metal ion-binding pocket toprim (E179A, D229A, D231A), catalytic region 5Y-CAP (R94A, D95A, Y98F) and the DNA-binding interface (K201A, G202E, R209A, K242A). A subset of substitutions reduced DSBs but maintained crossovers, demonstrating crossover homeostasis. Furthermore, a strong separation of function mutation (R304A) suggests that the crossover/non-crossover decision is established early by a protein–protein interaction surface of Rec12. Fission yeast has multiple crossovers per bivalent, and chromosome segregation was robust above a threshold of about one crossover per bivalent, below which non-disjunction occurred. These results support structural and functional conservation among Rec12/Spo11/Top6A family members for the catalysis of DSBs, and they reveal how Rec12 regulates other features of meiotic chromosome dynamics.
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Affiliation(s)
- Fengling Kan
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, 4301 West Markham Street (slot 516), Little Rock, AR 72205-7199, USA
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