1
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Luo C, Xu H, Yu Z, Liu D, Zhong D, Zhou S, Zhang B, Zhan J, Sun F. Meiotic chromatin-associated HSF5 is indispensable for pachynema progression and male fertility. Nucleic Acids Res 2024; 52:10255-10275. [PMID: 39162221 PMCID: PMC11417359 DOI: 10.1093/nar/gkae701] [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: 05/02/2024] [Revised: 07/04/2024] [Accepted: 08/07/2024] [Indexed: 08/21/2024] Open
Abstract
Pachynema progression contributes to the completion of prophase I. Nevertheless, the regulation of this significant meiotic process remains poorly understood. In this study, we identified a novel testis-specific protein HSF5, which regulates pachynema progression during male meiosis in a manner dependent on chromatin-binding. Deficiency of HSF5 results in meiotic arrest and male infertility, characterized as unconventional pachynema arrested at the mid-to-late stage, with extensive spermatocyte apoptosis. Our scRNA-seq data confirmed consistent expressional alterations of certain driver genes (Sycp1, Msh4, Meiob, etc.) crucial for pachynema progression in Hsf5-/- individuals. HSF5 was revealed to primarily bind to promoter regions of such key divers by CUT&Tag analysis. Also, our results demonstrated that HSF5 biologically interacted with SMARCA5, SMARCA4 and SMARCE1, and it could function as a transcription factor for pachynema progression during meiosis. Therefore, our study underscores the importance of the chromatin-associated HSF5 for the differentiation of spermatocytes, improving the protein regulatory network of the pachynema progression.
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Affiliation(s)
- Chunhai Luo
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Haoran Xu
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Ziqi Yu
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Dalin Liu
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Danyang Zhong
- Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Shumin Zhou
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Beibei Zhang
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Junfeng Zhan
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
| | - Fei Sun
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310016, China
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2
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Alavattam KG, Esparza JM, Hu M, Shimada R, Kohrs AR, Abe H, Munakata Y, Otsuka K, Yoshimura S, Kitamura Y, Yeh YH, Hu YC, Kim J, Andreassen PR, Ishiguro KI, Namekawa SH. ATF7IP2/MCAF2 directs H3K9 methylation and meiotic gene regulation in the male germline. Genes Dev 2024; 38:115-130. [PMID: 38383062 PMCID: PMC10982687 DOI: 10.1101/gad.351569.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 01/31/2024] [Indexed: 02/23/2024]
Abstract
H3K9 trimethylation (H3K9me3) plays emerging roles in gene regulation, beyond its accumulation on pericentric constitutive heterochromatin. It remains a mystery why and how H3K9me3 undergoes dynamic regulation in male meiosis. Here, we identify a novel, critical regulator of H3K9 methylation and spermatogenic heterochromatin organization: the germline-specific protein ATF7IP2 (MCAF2). We show that in male meiosis, ATF7IP2 amasses on autosomal and X-pericentric heterochromatin, spreads through the entirety of the sex chromosomes, and accumulates on thousands of autosomal promoters and retrotransposon loci. On the sex chromosomes, which undergo meiotic sex chromosome inactivation (MSCI), the DNA damage response pathway recruits ATF7IP2 to X-pericentric heterochromatin, where it facilitates the recruitment of SETDB1, a histone methyltransferase that catalyzes H3K9me3. In the absence of ATF7IP2, male germ cells are arrested in meiotic prophase I. Analyses of ATF7IP2-deficient meiosis reveal the protein's essential roles in the maintenance of MSCI, suppression of retrotransposons, and global up-regulation of autosomal genes. We propose that ATF7IP2 is a downstream effector of the DDR pathway in meiosis that coordinates the organization of heterochromatin and gene regulation through the spatial regulation of SETDB1-mediated H3K9me3 deposition.
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Affiliation(s)
- Kris G Alavattam
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
| | - Jasmine M Esparza
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Mengwen Hu
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Ryuki Shimada
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Anna R Kohrs
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Hironori Abe
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Yasuhisa Munakata
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Kai Otsuka
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Saori Yoshimura
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan
| | - Yuka Kitamura
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Yu-Han Yeh
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
| | - Yueh-Chiang Hu
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
| | - Jihye Kim
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
| | - Paul R Andreassen
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Kei-Ichiro Ishiguro
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto 860-0811, Japan;
| | - Satoshi H Namekawa
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA;
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California 95616, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
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3
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Ascencao CFR, Sims JR, Dziubek A, Comstock W, Fogarty EA, Badar J, Freire R, Grimson A, Weiss RS, Cohen PE, Smolka M. A TOPBP1 Allele Causing Male Infertility Uncouples XY Silencing Dynamics From Sex Body Formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543071. [PMID: 37398453 PMCID: PMC10312512 DOI: 10.1101/2023.05.31.543071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Meiotic sex chromosome inactivation (MSCI) is a critical feature of meiotic prophase I progression in males. While the ATR kinase and its activator TOPBP1 are key drivers of MSCI within the specialized sex body (SB) domain of the nucleus, how they promote silencing remains unclear given their multifaceted meiotic functions that also include DNA repair, chromosome synapsis and SB formation. Here we report a novel mutant mouse harboring mutations in the TOPBP1-BRCT5 domain. Topbp1 B5/B5 males are infertile, with impaired MSCI despite displaying grossly normal events of early prophase I, including synapsis and SB formation. Specific ATR-dependent events are disrupted including phosphorylation and localization of the RNA:DNA helicase Senataxin. Topbp1 B5/B5 spermatocytes initiate, but cannot maintain ongoing, MSCI. These findings reveal a non-canonical role for the ATR-TOPBP1 signaling axis in MSCI dynamics at advanced stages in pachynema and establish the first mouse mutant that separates ATR signaling and MSCI from SB formation.
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4
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Alavattam KG, Esparza JM, Hu M, Shimada R, Kohrs AR, Abe H, Munakata Y, Otsuka K, Yoshimura S, Kitamura Y, Yeh YH, Hu YC, Kim J, Andreassen PR, Ishiguro KI, Namekawa SH. ATF7IP2/MCAF2 directs H3K9 methylation and meiotic gene regulation in the male germline. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.30.560314. [PMID: 37873266 PMCID: PMC10592865 DOI: 10.1101/2023.09.30.560314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
H3K9 tri-methylation (H3K9me3) plays emerging roles in gene regulation, beyond its accumulation on pericentric constitutive heterochromatin. It remains a mystery why and how H3K9me3 undergoes dynamic regulation in male meiosis. Here, we identify a novel, critical regulator of H3K9 methylation and spermatogenic heterochromatin organization: the germline-specific protein ATF7IP2 (MCAF2). We show that, in male meiosis, ATF7IP2 amasses on autosomal and X pericentric heterochromatin, spreads through the entirety of the sex chromosomes, and accumulates on thousands of autosomal promoters and retrotransposon loci. On the sex chromosomes, which undergo meiotic sex chromosome inactivation (MSCI), the DNA damage response pathway recruits ATF7IP2 to X pericentric heterochromatin, where it facilitates the recruitment of SETDB1, a histone methyltransferase that catalyzes H3K9me3. In the absence of ATF7IP2, male germ cells are arrested in meiotic prophase I. Analyses of ATF7IP2-deficient meiosis reveal the protein's essential roles in the maintenance of MSCI, suppression of retrotransposons, and global upregulation of autosomal genes. We propose that ATF7IP2 is a downstream effector of the DDR pathway in meiosis that coordinates the organization of heterochromatin and gene regulation through the spatial regulation of SETDB1-mediated H3K9me3 deposition.
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Affiliation(s)
- Kris G. Alavattam
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington 98109, USA
- These authors contributed equally to this work
| | - Jasmine M. Esparza
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
- These authors contributed equally to this work
| | - Mengwen Hu
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
- These authors contributed equally to this work
| | - Ryuki Shimada
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811, Japan
- These authors contributed equally to this work
| | - Anna R. Kohrs
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
| | - Hironori Abe
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811, Japan
| | - Yasuhisa Munakata
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
| | - Kai Otsuka
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
| | - Saori Yoshimura
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811, Japan
| | - Yuka Kitamura
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
| | - Yu-Han Yeh
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
| | - Yueh-Chiang Hu
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
| | - Jihye Kim
- Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1, Yayoi, Tokyo, 113-0032, Japan
| | - Paul R. Andreassen
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
| | - Kei-ichiro Ishiguro
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811, Japan
| | - Satoshi H. Namekawa
- Reproductive Sciences Center, Division of Developmental Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio 45229, USA
- Department of Microbiology and Molecular Genetics, University of California, Davis, California 95616, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 49229, USA
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5
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Feng S, Wen H, Liu K, Xiong M, Li J, Gui Y, Lv C, Zhang J, Ma X, Wang X, Yuan S. hnRNPH1 establishes Sertoli-germ cell crosstalk through cooperation with PTBP1 and AR, and is essential for male fertility in mice. Development 2023; 150:dev201040. [PMID: 36718792 DOI: 10.1242/dev.201040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/03/2023] [Indexed: 02/01/2023]
Abstract
Spermatogenesis depends on the crosstalk of Sertoli cells (SCs) and germ cells. However, the gene regulatory network establishing the communications between SCs and germ cells remains unclear. Here, we report that heterogeneous nuclear ribonucleoprotein H1 (hnRNPH1) in SCs is essential for the establishment of crosstalk between SCs and germ cells. Conditional knockout of hnRNPH1 in mouse SCs leads to compromised blood-testis barrier function, delayed meiotic progression, increased germ cell apoptosis, sloughing of germ cells and, eventually, infertility of mice. Mechanistically, we discovered that hnRNPH1 could interact with the splicing regulator PTBP1 in SCs to regulate the pre-mRNA alternative splicing of the target genes functionally related to cell adhesion. Interestingly, we also found hnRNPH1 could cooperate with the androgen receptor, one of the SC-specific transcription factors, to modulate the transcription level of a group of genes associated with the cell-cell junction and EGFR pathway by directly binding to the gene promoters. Collectively, our findings reveal a crucial role for hnRNPH1 in SCs during spermatogenesis and uncover a potential molecular regulatory network involving hnRNPH1 in establishing Sertoli-germ cell crosstalk.
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Affiliation(s)
- Shenglei Feng
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Hui Wen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Kuan Liu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mengneng Xiong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jinmei Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yiqian Gui
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chunyu Lv
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jin Zhang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xixiang Ma
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Laboratory of Animal Center, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaoli Wang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
- Laboratory of Animal Center, Huazhong University of Science and Technology, Wuhan 430030, China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, Guangdong 518057, China
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6
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Abe H, Yeh YH, Munakata Y, Ishiguro KI, Andreassen PR, Namekawa SH. Active DNA damage response signaling initiates and maintains meiotic sex chromosome inactivation. Nat Commun 2022; 13:7212. [PMID: 36443288 PMCID: PMC9705562 DOI: 10.1038/s41467-022-34295-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 10/13/2022] [Indexed: 11/29/2022] Open
Abstract
Meiotic sex chromosome inactivation (MSCI) is an essential process in the male germline. While genetic experiments have established that the DNA damage response (DDR) pathway directs MSCI, due to limitations to the experimental systems available, mechanisms underlying MSCI remain largely unknown. Here we establish a system to study MSCI ex vivo, based on a short-term culture method, and demonstrate that active DDR signaling is required both to initiate and maintain MSCI via a dynamic and reversible process. DDR-directed MSCI follows two layers of modifications: active DDR-dependent reversible processes and irreversible histone post-translational modifications. Further, the DDR initiates MSCI independent of the downstream repressive histone mark H3K9 trimethylation (H3K9me3), thereby demonstrating that active DDR signaling is the primary mechanism of silencing in MSCI. By unveiling the dynamic nature of MSCI, and its governance by active DDR signals, our study highlights the sex chromosomes as an active signaling hub in meiosis.
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Affiliation(s)
- Hironori Abe
- grid.27860.3b0000 0004 1936 9684Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616 USA ,grid.274841.c0000 0001 0660 6749Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811 Japan
| | - Yu-Han Yeh
- grid.27860.3b0000 0004 1936 9684Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616 USA
| | - Yasuhisa Munakata
- grid.27860.3b0000 0004 1936 9684Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616 USA
| | - Kei-Ichiro Ishiguro
- grid.274841.c0000 0001 0660 6749Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, 860-0811 Japan
| | - Paul R. Andreassen
- grid.24827.3b0000 0001 2179 9593Division of Experimental Hematology & Cancer Biology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229 USA
| | - Satoshi H. Namekawa
- grid.27860.3b0000 0004 1936 9684Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616 USA
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7
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Marín-Gual L, González-Rodelas L, M. Garcias M, Kratochvíl L, Valenzuela N, Georges A, Waters PD, Ruiz-Herrera A. Meiotic chromosome dynamics and double strand break formation in reptiles. Front Cell Dev Biol 2022; 10:1009776. [PMID: 36313577 PMCID: PMC9597255 DOI: 10.3389/fcell.2022.1009776] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/23/2022] [Indexed: 11/13/2022] Open
Abstract
During meiotic prophase I, tightly regulated processes take place, from pairing and synapsis of homologous chromosomes to recombination, which are essential for the generation of genetically variable haploid gametes. These processes have canonical meiotic features conserved across different phylogenetic groups. However, the dynamics of meiotic prophase I in non-mammalian vertebrates are poorly known. Here, we compare four species from Sauropsida to understand the regulation of meiotic prophase I in reptiles: the Australian central bearded dragon (Pogona vitticeps), two geckos (Paroedura picta and Coleonyx variegatus) and the painted turtle (Chrysemys picta). We first performed a histological characterization of the spermatogenesis process in both the bearded dragon and the painted turtle. We then analyzed prophase I dynamics, including chromosome pairing, synapsis and the formation of double strand breaks (DSBs). We show that meiosis progression is highly conserved in reptiles with telomeres clustering forming the bouquet, which we propose promotes homologous pairing and synapsis, along with facilitating the early pairing of micro-chromosomes during prophase I (i.e., early zygotene). Moreover, we detected low levels of meiotic DSB formation in all taxa. Our results provide new insights into reptile meiosis.
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Affiliation(s)
- Laia Marín-Gual
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Laura González-Rodelas
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Maria M. Garcias
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Nicole Valenzuela
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, Australia
| | - Paul D. Waters
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, UNSW, Sydney, NSW, Australia
| | - Aurora Ruiz-Herrera
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- *Correspondence: Aurora Ruiz-Herrera,
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8
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PRC1-mediated epigenetic programming is required to generate the ovarian reserve. Nat Commun 2022; 13:4510. [PMID: 35948547 PMCID: PMC9365831 DOI: 10.1038/s41467-022-31759-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/30/2022] [Indexed: 11/16/2022] Open
Abstract
The ovarian reserve defines the female reproductive lifespan, which in humans spans decades due to robust maintenance of meiotic arrest in oocytes residing in primordial follicles. Epigenetic reprogramming, including DNA demethylation, accompanies meiotic entry, but the chromatin changes that underpin the generation and preservation of ovarian reserves are poorly defined. We report that the Polycomb Repressive Complex 1 (PRC1) establishes repressive chromatin states in perinatal mouse oocytes that directly suppress the gene expression program of meiotic prophase-I and thereby enable the transition to dictyate arrest. PRC1 dysfuction causes depletion of the ovarian reserve and leads to premature ovarian failure. Our study demonstrates a fundamental role for PRC1-mediated gene silencing in female reproductive lifespan, and reveals a critical window of epigenetic programming required to establish ovarian reserve. In humans, the ovarian reserve is maintained over decades by meiotic arrest of oocytes. Here the authors show that Polycomb Repressive Complex 1 (PRC1)-mediated epigenetic programming is essential for formation of ovarian reserve and thus female reproductive lifespan.
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9
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Xiong M, Zhou S, Feng S, Gui Y, Li J, Wu Y, Dong J, Yuan S. UHRF1 is indispensable for meiotic sex chromosome inactivation and interacts with the DNA damage response pathway in mice. Biol Reprod 2022; 107:168-182. [PMID: 35284939 DOI: 10.1093/biolre/ioac054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/04/2022] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
During male meiosis, the constitutively unsynapsed XY chromosomes undergo meiotic sex chromosome inactivation (MSCI), and the DNA damage response (DDR) pathway is critical for MSCI establishment. Our previous study showed that UHRF1(ubiquitin-like, with PHD and ring finger domains 1) deletion led to meiotic arrest and male infertility; however, the underlying mechanisms of UHRF1 in the regulation of meiosis remain unclear. Here, we report that UHRF1 is required for MSCI and cooperates with the DDR pathway in male meiosis. UHRF1-deficient spermatocytes display aberrant pairing and synapsis of homologous chromosomes during the pachytene stage. In addition, UHRF1 deficiency leads to aberrant recruitment of ATR and FANCD2 on the sex chromosomes and disrupts the diffusion of ATR to the XY chromatin. Furthermore, we show that UHRF1 acts as a cofactor of BRCA1 to facilitate the recruitment of DDR factors onto sex chromosomes for MSCI establishment. Accordingly, deletion of UHRF1 leads to the failure of meiotic silencing on sex chromosomes, resulting in meiotic arrest. In addition to our previous findings, the present study reveals that UHRF1 participates in MSCI, ensuring the progression of male meiosis. This suggests a multifunctional role of UHRF1 in the male germline.
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Affiliation(s)
- Mengneng Xiong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shumin Zhou
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shenglei Feng
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yiqian Gui
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jinmei Li
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yanqing Wu
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Juan Dong
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Shuiqiao Yuan
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.,Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, Guangdong 518057, China.,Laboratory of Animal Center, Huazhong University of Science and Technology, Wuhan 430030, China
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10
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The piRNA pathway is essential for generating functional oocytes in golden hamsters. Nat Cell Biol 2021; 23:1013-1022. [PMID: 34489574 DOI: 10.1038/s41556-021-00750-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/02/2021] [Indexed: 12/11/2022]
Abstract
Piwi-interacting RNAs (piRNAs) are predominantly expressed in germ cells and function in gametogenesis in various species. However, Piwi-deficient female mice are fertile and mouse oocytes express a panel of small RNAs that do not appear to be widely representative of mammals. Thus, the function of piRNAs in mammalian oogenesis remains largely unclear. Here, we generated Piwil1- and Mov10l1-deficient golden hamsters and found that all female and male mutants were sterile, with severe defects in embryogenesis and spermatogenesis, respectively. In Piwil1-deficient female hamsters, the oocytes and embryos displayed aberrant transposon accumulation and extensive transcriptomic dysregulation, and the embryos were arrested at the two-cell stage with impaired zygotic genome activation. Moreover, PIWIL1-piRNAs exert a non-redundant function in silencing endogenous retroviruses in the oocytes and embryos. Together, our findings demonstrate that piRNAs are indispensable for generating functional germ cells in golden hamsters and show the value of this model species for piRNA studies in gametogenesis, especially those related to female infertility.
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11
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Yeh YH, Hu M, Nakagawa T, Sakashita A, Yoshida S, Maezawa S, Namekawa SH. Isolation of Murine Spermatogenic Cells using a Violet-Excited Cell-Permeable DNA Binding Dye. J Vis Exp 2021:10.3791/61666. [PMID: 33522502 PMCID: PMC8260464 DOI: 10.3791/61666] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Isolation of meiotic spermatocytes is essential to investigate molecular mechanisms underlying meiosis and spermatogenesis. Although there are established cell isolation protocols using Hoechst 33342 staining in combination with fluorescence-activated cell sorting, it requires cell sorters equipped with an ultraviolet laser. Here we describe a cell isolation protocol using the DyeCycle Violet (DCV) stain, a low cytotoxicity DNA binding dye structurally similar to Hoechst 33342. DCV can be excited by both ultraviolet and violet lasers, which improves the flexibility of equipment choice, including a cell sorter not equipped with an ultraviolet laser. Using this protocol, one can isolate three live-cell subpopulations in meiotic prophase I, including leptotene/zygotene, pachytene, and diplotene spermatocytes, as well as post-meiotic round spermatids. We also describe a protocol to prepare single-cell suspension from mouse testes. Overall, the procedure requires a short time to complete (4-5 hours depending on the number of needed cells), which facilitates many downstream applications.
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Affiliation(s)
- Yu-Han Yeh
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine
| | - Mengwen Hu
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine
| | - Toshinori Nakagawa
- Division of Germ Cell Biology, National Institute for Basic Biology, National Institutes of Natural Sciences; Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (Sokendai)
| | - Akihiko Sakashita
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine
| | - Shosei Yoshida
- Division of Germ Cell Biology, National Institute for Basic Biology, National Institutes of Natural Sciences; Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (Sokendai)
| | - So Maezawa
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University; Faculty of Science and Technology, Department of Applied Biological Science, Tokyo University of Science
| | - Satoshi H Namekawa
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center; Department of Pediatrics, University of Cincinnati College of Medicine;
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12
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Maezawa S, Sakashita A, Yukawa M, Chen X, Takahashi K, Alavattam KG, Nakata I, Weirauch MT, Barski A, Namekawa SH. Super-enhancer switching drives a burst in gene expression at the mitosis-to-meiosis transition. Nat Struct Mol Biol 2020; 27:978-988. [PMID: 32895557 PMCID: PMC8690596 DOI: 10.1038/s41594-020-0488-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/10/2020] [Indexed: 01/12/2023]
Abstract
Due to bursts in the expression of thousands of germline-specific genes, the testis has the most diverse and complex transcriptome of all organs. By analyzing the male germline of mice, we demonstrate that the genome-wide reorganization of super-enhancers (SEs) drives bursts in germline gene expression after the mitosis-to-meiosis transition. SE reorganization is regulated by two molecular events: the establishment of meiosis-specific SEs via A-MYB (MYBL1), a key transcription factor for germline genes, and the resolution of SEs in mitotically proliferating cells via SCML2, a germline-specific Polycomb protein required for spermatogenesis-specific gene expression. Prior to entry into meiosis, meiotic SEs are preprogrammed in mitotic spermatogonia to ensure the unidirectional differentiation of spermatogenesis. We identify key regulatory factors for both mitotic and meiotic enhancers, revealing a molecular logic for the concurrent activation of mitotic enhancers and suppression of meiotic enhancers in the somatic and/or mitotic proliferation phases.
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Affiliation(s)
- So Maezawa
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA. .,Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan. .,Faculty of Science and Technology, Department of Applied Biological Science, Tokyo University of Science, Noda, Chiba, Japan.
| | - Akihiko Sakashita
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
| | - Masashi Yukawa
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Division of Allergy and Immunology, Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Xiaoting Chen
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Kazuki Takahashi
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kris G Alavattam
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Ippo Nakata
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa, Japan
| | - Matthew T Weirauch
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Divisions of Biomedical Informatics and Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Artem Barski
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Division of Allergy and Immunology, Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Satoshi H Namekawa
- Division of Reproductive Sciences, Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA. .,Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, USA.
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13
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Mirihagalle S, You T, Suh L, Patel C, Gao L, Rattan S, Qiao H. Prenatal exposure to di-(2-ethylhexyl) phthalate and high-fat diet synergistically disrupts mouse fetal oogenesis and affects folliculogenesis†. Biol Reprod 2020; 100:1561-1570. [PMID: 30939196 DOI: 10.1093/biolre/ioz051] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/21/2019] [Accepted: 03/29/2019] [Indexed: 12/12/2022] Open
Abstract
Di-(2-ethylhexyl) phthalate (DEHP) is a chemical that is widely used as a plasticizer. Exposure to DEHP has been shown to alter ovarian function in humans. Additionally, foods high in fat content, regularly found in the western diet, have been shown to be another potential disruptor of fetal ovarian function. Due to DEHP's lipophilicity, high-fat foods can be easily contaminated. Therefore, exposure to DEHP and a high-fat diet are both health concerns, especially in pregnant women, and the effects of these exposures on fetal oocyte quality and quantity should be elucidated. In this study, our goal was to determine if there are synergistic effects of DEHP exposure at an environmentally relevant level (20 μg/kg body weight/day) and high-fat diet on oogenesis and folliculogenesis. Dams were fed with a high-fat diet (45 kcal% fat) or a control diet (10 kcal% fat) 1 week before mating and during pregnancy and lactation. The pregnant mice were dosed with DEHP (20 μg/kg body weight/day) or vehicle control from E10.5 to litter birth. We found that treatment with an environmentally relevant dosage of DEHP and consumption of high-fat diet significantly increases synapsis defects in meiosis and affects folliculogenesis in the F1 generation.
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Affiliation(s)
- Supipi Mirihagalle
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Tianming You
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Lois Suh
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Chintan Patel
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Liying Gao
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Saniya Rattan
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Huanyu Qiao
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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14
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Alavattam KG, Namekawa SH. Licensing meiotic progression†. Biol Reprod 2020; 103:10-12. [PMID: 32338765 DOI: 10.1093/biolre/ioaa063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kris G Alavattam
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Satoshi H Namekawa
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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15
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Che L, Alavattam KG, Stambrook PJ, Namekawa SH, Du C. BRUCE preserves genomic stability in the male germline of mice. Cell Death Differ 2020; 27:2402-2416. [PMID: 32139899 DOI: 10.1038/s41418-020-0513-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 01/30/2020] [Accepted: 01/31/2020] [Indexed: 01/01/2023] Open
Abstract
BRUCE is a DNA damage response protein that promotes the activation of ATM and ATR for homologous recombination (HR) repair in somatic cells, making BRUCE a key protector of genomic stability. Preservation of genomic stability in the germline is essential for the maintenance of species. Here, we show that BRUCE is required for the preservation of genomic stability in the male germline of mice, specifically in spermatogonia and spermatocytes. Conditional knockout of Bruce in the male germline leads to profound defects in spermatogenesis, including impaired maintenance of spermatogonia and increased chromosomal anomalies during meiosis. Bruce-deficient pachytene spermatocytes frequently displayed persistent DNA breaks. Homologous synapsis was impaired, and nonhomologous associations and rearrangements were apparent in up to 10% of Bruce-deficient spermatocytes. Genomic instability was apparent in the form of chromosomal fragmentation, translocations, and synapsed quadrivalents and hexavalents. In addition, unsynapsed regions of rearranged autosomes were devoid of ATM and ATR signaling, suggesting an impairment in the ATM- and ATR-dependent DNA damage response of meiotic HR. Taken together, our study unveils crucial functions for BRUCE in the maintenance of spermatogonia and in the regulation of meiotic HR-functions that preserve the genomic stability of the male germline.
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Affiliation(s)
- Lixiao Che
- Department of Cell and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Kris G Alavattam
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Peter J Stambrook
- Department of Molecular Genetics, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Satoshi H Namekawa
- Division of Reproductive Sciences, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Chunying Du
- Department of Cell and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA.
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16
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The Initiation of Meiotic Sex Chromosome Inactivation Sequesters DNA Damage Signaling from Autosomes in Mouse Spermatogenesis. Curr Biol 2020; 30:408-420.e5. [PMID: 31902729 PMCID: PMC7076562 DOI: 10.1016/j.cub.2019.11.064] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/04/2019] [Accepted: 11/21/2019] [Indexed: 11/20/2022]
Abstract
Meiotic sex chromosome inactivation (MSCI) is an essential event in the mammalian male germline. MSCI is directed by a DNA damage response (DDR) pathway centered on the phosphorylation of histone variant H2AX at serine 139 (termed γH2AX). The failure to initiate MSCI is linked to complete meiotic arrest and elimination of germ cells; however, the mechanisms underlying this arrest and elimination remain unknown. To address this question, we established a new separation-of-function mouse model for H2ax that shows specific and complete defects in MSCI. The genetic change is a point mutation in which another H2AX amino acid residue important in the DDR, tyrosine 142 (Y142), is converted to alanine (H2ax-Y142A). In H2ax-Y142A meiosis, the establishment of DDR signals on the chromosome-wide domain of the sex chromosomes is impaired. The initiation of MSCI is required for stage progression, which enables crossover formation, suggesting that the establishment of MSCI permits the timely progression of male meiosis. Our results suggest that normal meiotic progression requires the removal of ATR-mediated DDR signaling from autosomes. We propose a novel biological function for MSCI: the initiation of MSCI sequesters DDR factors from autosomes to the sex chromosomes at the onset of the pachytene stage, and the subsequent formation of an isolated XY nuclear compartment-the XY body-sequesters DDR factors to permit meiotic progression from the mid-pachytene stage onward. VIDEO ABSTRACT.
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