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Li Q, Hariri S, Calidas A, Kaur A, Huey E, Engebrecht J. The chromatin-associated 53BP1 ortholog, HSR-9, regulates recombinational repair and X chromosome segregation in the Caenorhabditis elegans germ line. bioRxiv 2024:2024.04.12.589267. [PMID: 38659880 PMCID: PMC11042201 DOI: 10.1101/2024.04.12.589267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
53BP1 plays a crucial role in regulating DNA damage repair pathway choice and checkpoint signaling in somatic cells; however, its role in meiosis has remained enigmatic. In this study, we demonstrate that the Caenorhabditis elegans ortholog of 53BP1, HSR-9, associates with chromatin in both proliferating and meiotic germ cells. Notably, HSR-9 is enriched on the X chromosome pair in pachytene oogenic germ cells. HSR-9 is also present at kinetochores during both mitotic and meiotic divisions but does not appear to be essential for monitoring microtubule-kinetochore attachments or tension. Using cytological markers of different steps in recombinational repair, we found that HSR-9 influences the processing of a subset of meiotic double strand breaks into COSA-1-marked crossovers. Additionally, HSR-9 plays a role in meiotic X chromosome segregation under conditions where X chromosomes fail to pair, synapse, and recombine. Together, these results highlight that chromatin-associated HSR-9 has both conserved and unique functions in the regulation of meiotic chromosome behavior.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
| | - Sara Hariri
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
| | - Aashna Calidas
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Erica Huey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
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2
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Wang R, Li J, Tian Y, Sun Y, Zhang Y, Liu M, Zhang R, Zhao L, Li Q, Meng X, Zhou J, Gao J. The dynamic recruitment of LAB proteins senses meiotic chromosome axis differentiation in C. elegans. J Cell Biol 2024; 223:e202212035. [PMID: 38010234 PMCID: PMC10666650 DOI: 10.1083/jcb.202212035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 09/19/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
During meiosis, cohesin and meiosis-specific proteins organize chromatin into an axis-loop architecture, coordinating homologous synapsis, recombination, and ordered chromosome segregation. However, how the meiotic chromosome axis is assembled and differentiated with meiotic progression remains elusive. Here, we explore the dynamic recruitment of two long arms of the bivalent proteins, LAB-1 and LAB-2, in Caenorhabditis elegans. LAB proteins directly interact with the axis core HORMA complexes and weak interactions contribute to their recruitment. LAB proteins phase separate in vitro, and this capacity is promoted by HORMA complexes. During early prophase, synapsis oppositely regulates the axis enrichment of LAB proteins. After the pachytene exit, LAB proteins switch from a reciprocal localization pattern to a colocalization pattern, and the normal dynamic pattern of LAB proteins is altered in meiotic mutants. We propose that LAB recruitment senses axis differentiation, and phase separation of meiotic structures helps subdomain establishment and accurate segregation of the chromosomes.
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Affiliation(s)
- Ruoxi Wang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Jiaxiang Li
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Yuqi Tian
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Yating Sun
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Yu Zhang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Mengfei Liu
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Ruirui Zhang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Li Zhao
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Qian Li
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaoqian Meng
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, China
| | - Jinmin Gao
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, China
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3
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Kounosu A, Sun S, Maeda Y, Dayi M, Yoshida A, Maruyama H, Hunt V, Sugimoto A, Kikuchi T. Syntenic relationship of chromosomes in Strongyloides species and Rhabditophanes diutinus based on the chromosome-level genome assemblies. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220446. [PMID: 38008120 PMCID: PMC10676810 DOI: 10.1098/rstb.2022.0446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/25/2023] [Indexed: 11/28/2023] Open
Abstract
The Strongyloides clade, to which the parasitic nematode genus Strongyloides belongs, contains taxa with diverse lifestyles, ranging from free-living to obligate vertebrate parasites. Reproductive strategies are also diverse in this group of nematodes, employing not only sexual reproduction but also parthenogenesis, making it an attractive group to study genome adaptation to specific conditions. An in-depth understanding of genome evolution, however, has been hampered by fragmented genome assemblies. In this study, we generated chromosome-level genome assemblies for two Strongyloides species and the outgroup species Rhabditophanes diutinus using long-read sequencing and high-throughput chromosome conformation capture (Hi-C). Our synteny analyses revealed a clearer picture of chromosome evolution in this group, suggesting that a functional sex chromosome has been maintained throughout the group. We further investigated sex chromosome dynamics in the lifecycle of Strongyloides ratti and found that bivalent formation in oocytes appears to be important for male production in the mitotic parthenogenesis. This article is part of the Theo Murphy meeting issue 'Strongyloides: omics to worm-free populations'.
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Affiliation(s)
- Asuka Kounosu
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
- Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan
| | - Simo Sun
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
| | - Yasunobu Maeda
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
- Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan
| | - Mehmet Dayi
- Forestry Vocational School, Duzce University, 81620 Duzce, Türkiye
| | - Akemi Yoshida
- Frontier Science Research Center, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Haruhiko Maruyama
- Department of Infectious Diseases, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan
| | - Vicky Hunt
- Department of Biology and Biochemistry, University of Bath, Bath BA27AY, UK
| | - Asako Sugimoto
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Taisei Kikuchi
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8562, Japan
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4
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Tian Y, Liu L, Gao J, Wang R. Homologous chromosome pairing: The linchpin of accurate segregation in meiosis. J Cell Physiol 2024; 239:3-19. [PMID: 38032002 DOI: 10.1002/jcp.31166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 11/13/2023] [Accepted: 11/20/2023] [Indexed: 12/01/2023]
Abstract
Meiosis is a specialized cell division that occurs in sexually reproducing organisms, generating haploid gametes containing half the chromosome number through two rounds of cell division. Homologous chromosomes pair and prepare for their proper segregation in subsequent divisions. How homologous chromosomes recognize each other and achieve pairing is an important question. Early studies showed that in most organisms, homologous pairing relies on homologous recombination. However, pairing mechanisms differ across species. Evidence indicates that chromosomes are dynamic and move during early meiotic stages, facilitating pairing. Recent studies in various model organisms suggest conserved mechanisms and key regulators of homologous chromosome pairing. This review summarizes these findings and compare similarities and differences in homologous chromosome pairing mechanisms across species.
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Affiliation(s)
- Yuqi Tian
- Center for Cell Structure and Function, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, China
| | - Libo Liu
- Center for Cell Structure and Function, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, China
| | - Jinmin Gao
- Center for Cell Structure and Function, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, China
| | - Ruoxi Wang
- Center for Cell Structure and Function, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, China
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5
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Fernández-Álvarez A. Beyond tradition: exploring the non-canonical functions of telomeres in meiosis. Front Cell Dev Biol 2023; 11:1278571. [PMID: 38020928 PMCID: PMC10679444 DOI: 10.3389/fcell.2023.1278571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023] Open
Abstract
The telomere bouquet is a specific chromosomal configuration that forms during meiosis at the zygotene stage, when telomeres cluster together at the nuclear envelope. This clustering allows cytoskeleton-induced movements to be transmitted to the chromosomes, thereby facilitating homologous chromosome search and pairing. However, loss of the bouquet results in more severe meiotic defects than can be attributed solely to recombination problems, suggesting that the bouquet's full function remains elusive. Despite its transient nature and the challenges in performing in vivo analyses, information is emerging that points to a remarkable suite of non-canonical functions carried out by the bouquet. Here, we describe how new approaches in quantitative cell biology can contribute to establishing the molecular basis of the full function and plasticity of the bouquet, and thus generate a comprehensive picture of the telomeric control of meiosis.
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Affiliation(s)
- Alfonso Fernández-Álvarez
- Institute of Functional Biology and Genomics (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, Salamanca, Spain
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6
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Robert VJ, Caron M, Gely L, Adrait A, Pakulska V, Couté Y, Chevalier M, Riedel CG, Bedet C, Palladino F. SIN-3 acts in distinct complexes to regulate the germline transcriptional program in Caenorhabditis elegans. Development 2023; 150:dev201755. [PMID: 38771303 PMCID: PMC10617626 DOI: 10.1242/dev.201755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 09/18/2023] [Indexed: 10/12/2023]
Abstract
The transcriptional co-regulator SIN3 influences gene expression through multiple interactions that include histone deacetylases. Haploinsufficiency and mutations in SIN3 are the underlying cause of Witteveen-Kolk syndrome and related intellectual disability and autism syndromes, emphasizing its key role in development. However, little is known about the diversity of its interactions and functions in developmental processes. Here, we show that loss of SIN-3, the single SIN3 homolog in Caenorhabditis elegans, results in maternal-effect sterility associated with de-regulation of the germline transcriptome, including de-silencing of X-linked genes. We identify at least two distinct SIN3 complexes containing specific histone deacetylases and show that they differentially contribute to fertility. Single-cell, single-molecule fluorescence in situ hybridization reveals that in sin-3 mutants the X chromosome becomes re-expressed prematurely and in a stochastic manner in individual germ cells, suggesting a role for SIN-3 in its silencing. Furthermore, we identify histone residues whose acetylation increases in the absence of SIN-3. Together, this work provides a powerful framework for the in vivo study of SIN3 and associated proteins.
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Affiliation(s)
- Valerie J. Robert
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, 69007 Lyon, France
| | - Matthieu Caron
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, 69007 Lyon, France
| | - Loic Gely
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, 69007 Lyon, France
| | - Annie Adrait
- Grenoble Alpes, CEA, Inserm, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Victoria Pakulska
- Grenoble Alpes, CEA, Inserm, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Yohann Couté
- Grenoble Alpes, CEA, Inserm, UA13 BGE, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Manon Chevalier
- Department of Biosciences and Nutrition, Karolinska Institutet, Blickagången 16, 14157 Huddinge, Sweden
| | - Christian G. Riedel
- Department of Biosciences and Nutrition, Karolinska Institutet, Blickagången 16, 14157 Huddinge, Sweden
| | - Cecile Bedet
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, 69007 Lyon, France
| | - Francesca Palladino
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, 69007 Lyon, France
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7
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Xie D, Gu B, Liu Y, Ye P, Ma Y, Wen T, Song X, Zhao Z. Efficient targeted recombination with CRISPR/Cas9 in hybrids of Caenorhabditis nematodes with suppressed recombination. BMC Biol 2023; 21:203. [PMID: 37775783 PMCID: PMC10542263 DOI: 10.1186/s12915-023-01704-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 09/18/2023] [Indexed: 10/01/2023] Open
Abstract
BACKGROUND Homology-based recombination (HR) is the cornerstone of genetic mapping. However, a lack of sufficient sequence homology or the presence of a genomic rearrangement prevents HR through crossing, which inhibits genetic mapping in relevant genomic regions. This is particularly true in species hybrids whose genomic sequences are highly divergent along with various genome arrangements, making the mapping of genetic loci, such as hybrid incompatibility (HI) loci, through crossing impractical. We previously mapped tens of HI loci between two nematodes, Caenorhabditis briggsae and C. nigoni, through the repeated backcrossing of GFP-linked C. briggsae fragments into C. nigoni. However, the median introgression size was over 7 Mb, indicating apparent HR suppression and preventing the subsequent cloning of the causative gene underlying a given HI phenotype. Therefore, a robust method that permits recombination independent of sequence homology is desperately desired. RESULTS Here, we report a method of highly efficient targeted recombination (TR) induced by CRISPR/Cas9 with dual guide RNAs (gRNAs), which circumvents the HR suppression in hybrids between the two species. We demonstrated that a single gRNA was able to induce efficient TR between highly homologous sequences only in the F1 hybrids but not in the hybrids that carry a GFP-linked C. briggsae fragment in an otherwise C. nigoni background. We achieved highly efficient TR, regardless of sequence homology or genetic background, when dual gRNAs were used that each specifically targeted one parental chromosome. We further showed that dual gRNAs were able to induce efficient TR within genomic regions that had undergone inversion, in which HR-based recombination was expected to be suppressed, supporting the idea that dual-gRNA-induced TR can be achieved through nonhomology-based end joining between two parental chromosomes. CONCLUSIONS Recombination suppression can be circumvented through CRISPR/Cas9 with dual gRNAs, regardless of sequence homology or the genetic background of the species hybrid. This method is expected to be applicable to other situations in which recombination is suppressed in interspecies or intrapopulation hybrids.
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Affiliation(s)
- Dongying Xie
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Bida Gu
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, USA
| | - Yiqing Liu
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Pohao Ye
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Yiming Ma
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Tongshu Wen
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Xiaoyuan Song
- MOE Key Laboratory of Cellular Dynamics, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Zhongying Zhao
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.
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8
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Castellano-Pozo M, Sioutas G, Barroso C, Prince JP, Lopez-Jimenez P, Davy J, Jaso-Tamame AL, Crawley O, Shao N, Page J, Martinez-Perez E. The kleisin subunit controls the function of C. elegans meiotic cohesins by determining the mode of DNA binding and differential regulation by SCC-2 and WAPL-1. eLife 2023; 12:e84138. [PMID: 37650378 PMCID: PMC10497282 DOI: 10.7554/elife.84138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 07/29/2023] [Indexed: 09/01/2023] Open
Abstract
The cohesin complex plays essential roles in chromosome segregation, 3D genome organisation, and DNA damage repair through its ability to modify DNA topology. In higher eukaryotes, meiotic chromosome function, and therefore fertility, requires cohesin complexes containing meiosis-specific kleisin subunits: REC8 and RAD21L in mammals and REC-8 and COH-3/4 in Caenorhabditis elegans. How these complexes perform the multiple functions of cohesin during meiosis and whether this involves different modes of DNA binding or dynamic association with chromosomes is poorly understood. Combining time-resolved methods of protein removal with live imaging and exploiting the temporospatial organisation of the C. elegans germline, we show that REC-8 complexes provide sister chromatid cohesion (SCC) and DNA repair, while COH-3/4 complexes control higher-order chromosome structure. High-abundance COH-3/4 complexes associate dynamically with individual chromatids in a manner dependent on cohesin loading (SCC-2) and removal (WAPL-1) factors. In contrast, low-abundance REC-8 complexes associate stably with chromosomes, tethering sister chromatids from S-phase until the meiotic divisions. Our results reveal that kleisin identity determines the function of meiotic cohesin by controlling the mode and regulation of cohesin-DNA association, and are consistent with a model in which SCC and DNA looping are performed by variant cohesin complexes that coexist on chromosomes.
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Affiliation(s)
| | | | | | - Josh P Prince
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | | | - Joseph Davy
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | | | - Oliver Crawley
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Nan Shao
- MRC London Institute of Medical SciencesLondonUnited Kingdom
| | - Jesus Page
- Universidad Autónoma de MadridMadridSpain
| | - Enrique Martinez-Perez
- MRC London Institute of Medical SciencesLondonUnited Kingdom
- Imperial College Faculty of MedicineLondonUnited Kingdom
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9
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Liu C, Rex R, Lung Z, Wang JS, Wu F, Kim HJ, Zhang L, Sohn LL, Dernburg AF. A cooperative network at the nuclear envelope counteracts LINC-mediated forces during oogenesis in C. elegans. Sci Adv 2023; 9:eabn5709. [PMID: 37436986 PMCID: PMC10337908 DOI: 10.1126/sciadv.abn5709] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023]
Abstract
Oogenesis involves transduction of mechanical forces from the cytoskeleton to the nuclear envelope (NE). In Caenorhabditis elegans, oocyte nuclei lacking the single lamin protein LMN-1 are vulnerable to collapse under forces mediated through LINC (linker of nucleoskeleton and cytoskeleton) complexes. Here, we use cytological analysis and in vivo imaging to investigate the balance of forces that drive this collapse and protect oocyte nuclei. We also use a mechano-node-pore sensing device to directly measure the effect of genetic mutations on oocyte nuclear stiffness. We find that nuclear collapse is not a consequence of apoptosis. It is promoted by dynein, which induces polarization of a LINC complex composed of Sad1 and UNC-84 homology 1 (SUN-1) and ZYGote defective 12 (ZYG-12). Lamins contribute to oocyte nuclear stiffness and cooperate with other inner nuclear membrane proteins to distribute LINC complexes and protect nuclei from collapse. We speculate that a similar network may protect oocyte integrity during extended oocyte arrest in mammals.
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Affiliation(s)
- Chenshu Liu
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Rachel Rex
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Zoe Lung
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - John S. Wang
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Fan Wu
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Hyung Jun Kim
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Liangyu Zhang
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Lydia L. Sohn
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Abby F. Dernburg
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
- Department of Biological Sciences and Engineering, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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10
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Abstract
The successful delivery of genetic material to gametes requires tightly regulated interactions between the parental chromosomes. Central to this regulation is a conserved chromosomal interface called the synaptonemal complex (SC), which brings the parental chromosomes in close proximity along their length. While many of its components are known, the interfaces that mediate the assembly of the SC remain a mystery. Here, we survey findings from different model systems while focusing on insight gained in the nematode C. elegans. We synthesize our current understanding of the structure, dynamics, and biophysical properties of the SC and propose mechanisms for SC assembly.
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Affiliation(s)
- Spencer G. Gordon
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, Salt Lake City, Utah, United States of America
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11
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Tabara H, Mitani S, Mochizuki M, Kohara Y, Nagata K. A small RNA system ensures accurate homologous pairing and unpaired silencing of meiotic chromosomes. EMBO J 2023; 42:e105002. [PMID: 37078421 PMCID: PMC10233376 DOI: 10.15252/embj.2020105002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/21/2023] Open
Abstract
During meiosis, chromosomes with homologous partners undergo synaptonemal complex (SC)-mediated pairing, while the remaining unpaired chromosomes are heterochromatinized through unpaired silencing. Mechanisms underlying homolog recognition during SC formation are still unclear. Here, we show that the Caenorhabditis elegans Argonaute proteins, CSR-1 and its paralog CSR-2, interacting with 22G-RNAs, are required for synaptonemal complex formation with accurate homology. CSR-1 in nuclei and meiotic cohesin, constituting the SC lateral elements, were associated with nonsimple DNA repeats, including minisatellites and transposons, and weakly associated with coding genes. CSR-1-associated CeRep55 minisatellites were expressing 22G-RNAs and long noncoding (lnc) RNAs that colocalized with synaptonemal complexes on paired chromosomes and with cohesin regions of unpaired chromosomes. CeRep55 multilocus deletions reduced the efficiencies of homologous pairing and unpaired silencing, which were supported by the csr-1 activity. Moreover, CSR-1 and CSR-2 were required for proper heterochromatinization of unpaired chromosomes. These findings suggest that CSR-1 and CSR-2 play crucial roles in homology recognition, achieving accurate SC formation between chromosome pairs and condensing unpaired chromosomes by targeting repeat-derived lncRNAs.
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Affiliation(s)
- Hiroaki Tabara
- Advanced Genomics CenterNational Institute of GeneticsShizuokaJapan
- Tokyo Women's Medical UniversityTokyoJapan
- Faculty of MedicineUniversity of TsukubaIbarakiJapan
| | | | | | - Yuji Kohara
- Advanced Genomics CenterNational Institute of GeneticsShizuokaJapan
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12
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Gong T, McNally FJ. Caenorhabditis elegans spermatocytes can segregate achiasmate homologous chromosomes apart at higher than random frequency during meiosis I. Genetics 2023; 223:iyad021. [PMID: 36792551 PMCID: PMC10319977 DOI: 10.1093/genetics/iyad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/05/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023] Open
Abstract
Chromosome segregation errors during meiosis are the leading cause of aneuploidy. Faithful chromosome segregation during meiosis in most eukaryotes requires a crossover which provides a physical attachment holding homologs together in a "bivalent." Crossovers are critical for homologs to be properly aligned and partitioned in the first meiotic division. Without a crossover, individual homologs (univalents) might segregate randomly, resulting in aneuploid progeny. However, Caenorhabditis elegans zim-2 mutants, which have crossover defects on chromosome V, have fewer dead embryos than that expected from random segregation. This deviation from random segregation is more pronounced in zim-2 males than that in females. We found three phenomena that can explain this apparent discrepancy. First, we detected crossovers on chromosome V in both zim-2(tm574) oocytes and spermatocytes, suggesting a redundant mechanism to make up for the ZIM-2 loss. Second, after accounting for the background crossover frequency, spermatocytes produced significantly more euploid gametes than what would be expected from random segregation. Lastly, trisomy of chromosome V is viable and fertile. Together, these three phenomena allow zim-2(tm574) mutants with reduced crossovers on chromosome V to have more viable progeny. Furthermore, live imaging of meiosis in spo-11(me44) oocytes and spermatocytes, which exhibit crossover failure on all 6 chromosomes, showed 12 univalents segregating apart in roughly equal masses in a homology-independent manner, supporting the existence of a mechanism that segregates any 2 chromosomes apart.
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Affiliation(s)
- Ting Gong
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Francis J McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
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13
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Russo AE, Giacopazzi S, Deshong A, Menon M, Ortiz V, Ego KM, Corbett KD, Bhalla N. The conserved AAA ATPase PCH-2 distributes its regulation of meiotic prophase events through multiple meiotic HORMADs in C. elegans. PLoS Genet 2023; 19:e1010708. [PMID: 37058535 PMCID: PMC10132761 DOI: 10.1371/journal.pgen.1010708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 04/26/2023] [Accepted: 03/21/2023] [Indexed: 04/15/2023] Open
Abstract
During meiotic prophase, the essential events of homolog pairing, synapsis, and recombination are coordinated with meiotic progression to promote fidelity and prevent aneuploidy. The conserved AAA+ ATPase PCH-2 coordinates these events to guarantee crossover assurance and accurate chromosome segregation. How PCH-2 accomplishes this coordination is poorly understood. Here, we provide evidence that PCH-2 decelerates pairing, synapsis and recombination in C. elegans by remodeling meiotic HORMADs. We propose that PCH-2 converts the closed versions of these proteins, which drive these meiotic prophase events, to unbuckled conformations, destabilizing interhomolog interactions and delaying meiotic progression. Further, we find that PCH-2 distributes this regulation among three essential meiotic HORMADs in C. elegans: PCH-2 acts through HTP-3 to regulate pairing and synapsis, HIM-3 to promote crossover assurance, and HTP-1 to control meiotic progression. In addition to identifying a molecular mechanism for how PCH-2 regulates interhomolog interactions, our results provide a possible explanation for the expansion of the meiotic HORMAD family as a conserved evolutionary feature of meiosis. Taken together, our work demonstrates that PCH-2's remodeling of meiotic HORMADs has functional consequences for the rate and fidelity of homolog pairing, synapsis, recombination and meiotic progression, ensuring accurate meiotic chromosome segregation.
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Affiliation(s)
- Anna E. Russo
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Stefani Giacopazzi
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Alison Deshong
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Malaika Menon
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Valery Ortiz
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Kaori M. Ego
- Department of Cellular and Molecular Medicine, University of California, San Diego, California, United States of America
| | - Kevin D. Corbett
- Department of Cellular and Molecular Medicine, University of California, San Diego, California, United States of America
| | - Needhi Bhalla
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
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14
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Kim HJ, Liu C, Zhang L, Dernburg AF. MJL-1 is a nuclear envelope protein required for homologous chromosome pairing and regulation of synapsis during meiosis in C. elegans. Sci Adv 2023; 9:eadd1453. [PMID: 36753547 PMCID: PMC9908027 DOI: 10.1126/sciadv.add1453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Interactions between chromosomes and LINC (linker of nucleoskeleton and cytoskeleton) complexes in the nuclear envelope (NE) promote homolog pairing and synapsis during meiosis. By tethering chromosomes to cytoskeletal motors, these connections lead to processive chromosome movements along the NE. This activity is usually mediated by telomeres, but in the nematode Caenorhabditis elegans, special chromosome regions called "pairing centers" (PCs) have acquired this meiotic function. Here, we identify a previously uncharacterized meiosis-specific NE protein, MJL-1 (MAJIN-Like-1), that is essential for interactions between PCs and LINC complexes in C. elegans. Mutations in MJL-1 eliminate active chromosome movements during meiosis, resulting in nonhomologous synapsis and impaired homolog pairing. Fission yeast and mice also require NE proteins to connect chromosomes to LINC complexes. Extensive similarities in the molecular architecture of meiotic chromosome-NE attachments across eukaryotes suggest a common origin and/or functions of this architecture during meiosis.
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Affiliation(s)
- Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Chenshu Liu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Liangyu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Abby F. Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
- Biological Sciences and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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15
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Martinez-Garcia M, Naharro PR, Skinner MW, Baran KA, Lascarez-Lagunas LI, Nadarajan S, Shin N, Silva-García CG, Saito TT, Beese-Sims S, Diaz-Pacheco BN, Berson E, Castañer AB, Pacheco S, Martinez-Perez E, Jordan PW, Colaiácovo MP. GRAS-1 is a novel regulator of early meiotic chromosome dynamics in C. elegans. PLoS Genet 2023; 19:e1010666. [PMID: 36809245 PMCID: PMC9983901 DOI: 10.1371/journal.pgen.1010666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 03/03/2023] [Accepted: 02/13/2023] [Indexed: 02/23/2023] Open
Abstract
Chromosome movements and licensing of synapsis must be tightly regulated during early meiosis to ensure accurate chromosome segregation and avoid aneuploidy, although how these steps are coordinated is not fully understood. Here we show that GRAS-1, the worm homolog of mammalian GRASP/Tamalin and CYTIP, coordinates early meiotic events with cytoskeletal forces outside the nucleus. GRAS-1 localizes close to the nuclear envelope (NE) in early prophase I and interacts with NE and cytoskeleton proteins. Delayed homologous chromosome pairing, synaptonemal complex (SC) assembly, and DNA double-strand break repair progression are partially rescued by the expression of human CYTIP in gras-1 mutants, supporting functional conservation. However, Tamalin, Cytip double knockout mice do not exhibit obvious fertility or meiotic defects, suggesting evolutionary differences between mammals. gras-1 mutants show accelerated chromosome movement during early prophase I, implicating GRAS-1 in regulating chromosome dynamics. GRAS-1-mediated regulation of chromosome movement is DHC-1-dependent, placing it acting within the LINC-controlled pathway, and depends on GRAS-1 phosphorylation at a C-terminal S/T cluster. We propose that GRAS-1 coordinates the early steps of homology search and licensing of SC assembly by regulating the pace of chromosome movement in early prophase I.
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Affiliation(s)
- Marina Martinez-Garcia
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pedro Robles Naharro
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marnie W Skinner
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Kerstin A Baran
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Laura I Lascarez-Lagunas
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Saravanapriah Nadarajan
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nara Shin
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carlos G Silva-García
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Takamune T Saito
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sara Beese-Sims
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brianna N Diaz-Pacheco
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Elizaveta Berson
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ana B Castañer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarai Pacheco
- MRC London Institute of Medical Sciences, London, United Kingdom
| | | | - Philip W Jordan
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Monica P Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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16
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Zhang L, Stauffer WT, Wang JS, Wu F, Yu Z, Liu C, Kim HJ, Dernburg AF. Recruitment of Polo-like kinase couples synapsis to meiotic progression via inactivation of CHK-2. eLife 2023; 12:84492. [PMID: 36700544 PMCID: PMC9998088 DOI: 10.7554/elife.84492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/25/2023] [Indexed: 01/27/2023] Open
Abstract
Meiotic chromosome segregation relies on synapsis and crossover (CO) recombination between homologous chromosomes. These processes require multiple steps that are coordinated by the meiotic cell cycle and monitored by surveillance mechanisms. In diverse species, failures in chromosome synapsis can trigger a cell cycle delay and/or lead to apoptosis. How this key step in 'homolog engagement' is sensed and transduced by meiotic cells is unknown. Here we report that in C. elegans, recruitment of the Polo-like kinase PLK-2 to the synaptonemal complex triggers phosphorylation and inactivation of CHK-2, an early meiotic kinase required for pairing, synapsis, and double-strand break (DSB) induction. Inactivation of CHK-2 terminates DSB formation and enables CO designation and cell cycle progression. These findings illuminate how meiotic cells ensure CO formation and accurate chromosome segregation.
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Affiliation(s)
- Liangyu Zhang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Weston T Stauffer
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Department of Integrative Biology, University of California, BerkeleyBerkeleyUnited States
| | - John S Wang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Fan Wu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Zhouliang Yu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Chenshu Liu
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
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17
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Trivedi S, Blazícková J, Silva N. PARG and BRCA1-BARD1 cooperative function regulates DNA repair pathway choice during gametogenesis. Nucleic Acids Res 2022; 50:12291-12308. [PMID: 36478097 PMCID: PMC9757042 DOI: 10.1093/nar/gkac1153] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/09/2022] [Accepted: 11/18/2022] [Indexed: 12/14/2022] Open
Abstract
Meiotic chromosome segregation relies on programmed DNA double-strand break induction. These are in turn repaired by homologous recombination, generating physical attachments between the parental chromosomes called crossovers. A subset of breaks yields recombinant outcomes, while crossover-independent mechanisms repair the majority of lesions. The balance between different repair pathways is crucial to ensure genome integrity. We show that Caenorhabditis elegans BRC-1/BRCA1-BRD-1/BARD1 and PARG-1/PARG form a complex in vivo, essential for accurate DNA repair in the germline. Simultaneous depletion of BRC-1 and PARG-1 causes synthetic lethality due to reduced crossover formation and impaired break repair, evidenced by hindered RPA-1 removal and presence of aberrant chromatin bodies in diakinesis nuclei, whose formation depends on spo-11 function. These factors undergo a similar yet independent loading in developing oocytes, consistent with operating in different pathways. Abrogation of KU- or Theta-mediated end joining elicits opposite effects in brc-1; parg-1 doubles, suggesting a profound impact in influencing DNA repair pathway choice by BRC-1-PARG-1. Importantly, lack of PARG-1 catalytic activity suppresses untimely accumulation of RAD-51 foci in brc-1 mutants but is only partially required for fertility. Our data show that BRC-1/BRD-1-PARG-1 joint function is essential for genome integrity in meiotic cells by regulating multiple DNA repair pathways.
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Affiliation(s)
- Shalini Trivedi
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Jitka Blazícková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Nicola Silva
- To whom correspondence should be addressed. Tel: +420 549 49 8033;
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18
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Rourke C, Jaramillo-Lambert A. TOP-2 is differentially required for the proper maintenance of the cohesin subunit REC-8 on meiotic chromosomes in Caenorhabditis elegans spermatogenesis and oogenesis. Genetics 2022; 222:iyac120. [PMID: 35951744 PMCID: PMC9526062 DOI: 10.1093/genetics/iyac120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/01/2022] [Indexed: 11/14/2022] Open
Abstract
During meiotic prophase I, accurate segregation of homologous chromosomes requires the establishment of chromosomes with a meiosis-specific architecture. The sister chromatid cohesin complex and the enzyme Topoisomerase II (TOP-2) are important components of meiotic chromosome architecture, but the relationship of these proteins in the context of meiotic chromosome segregation is poorly defined. Here, we analyzed the role of TOP-2 in the timely release of the sister chromatid cohesin subunit REC-8 during spermatogenesis and oogenesis of Caenorhabditis elegans. We show that there is a different requirement for TOP-2 in meiosis of spermatogenesis and oogenesis. The loss-of-function mutation top-2(it7) results in premature REC-8 removal in spermatogenesis, but not oogenesis. This correlates with a failure to maintain the HORMA-domain proteins HTP-1 and HTP-2 (HTP-1/2) on chromosome axes at diakinesis and mislocalization of the downstream components that control REC-8 release including Aurora B kinase. In oogenesis, top-2(it7) causes a delay in the localization of Aurora B to oocyte chromosomes but can be rescued through premature activation of the maturation promoting factor via knockdown of the inhibitor kinase WEE-1.3. The delay in Aurora B localization is associated with an increase in the length of diakinesis bivalents and wee-1.3 RNAi mediated rescue of Aurora B localization in top-2(it7) is associated with a decrease in diakinesis bivalent length. Our results imply that the sex-specific effects of TOP-2 on REC-8 release are due to differences in the temporal regulation of meiosis and chromosome structure in late prophase I in spermatogenesis and oogenesis.
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Affiliation(s)
- Christine Rourke
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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19
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Priyadarshini M, AlHarbi S, Frøkjær-Jensen C. Acute and inherited piRNA-mediated silencing in a rde-3 ribonucleotidyltransferase mutant. MicroPubl Biol 2022; 2022:10.17912/micropub.biology.000638. [PMID: 36188099 PMCID: PMC9520340 DOI: 10.17912/micropub.biology.000638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/04/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022]
Abstract
We recently developed a piRNA-based silencing assay (piRNAi) to study small-RNA mediated epigenetic silencing: acute gene silencing is induced by synthetic piRNAs expressed from extra-chromosomal array and transgenerational inheritance can be quantified after array loss. The assay allows inheritance assays by injecting piRNAs directly into mutant animals and targeting endogenous genes ( e.g. , him-5 and him-8 ) with obvious phenotypes (increased male frequency). Here we demonstrate the piRNAi assay by quantifying acute and inherited silencing in the ribonucleotidyltransferase rde-3 (ne3370) mutant. In the absence of rde-3, acute silencing was reduced but still detectable, whereas inherited silencing was abolished.
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Affiliation(s)
- Monika Priyadarshini
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
,
Current address: Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sarah AlHarbi
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
,
Correspondence to: Christian Frøkjær-Jensen (
)
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20
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Billmyre KK. Chromosome-specific behaviors during early meiosis. Curr Top Dev Biol 2022; 151:127-154. [PMID: 36681468 DOI: 10.1016/bs.ctdb.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Inheriting the wrong number of chromosomes is one of the leading causes of infertility and birth defects in humans. However, in many organisms, individual chromosomes vary dramatically in both organization, sequence, and size. Chromosome segregation systems must be capable of accounting for these differences to reliably segregate chromosomes. During gametogenesis, meiosis ensures that all chromosomes segregate properly into gametes (i.e., egg or sperm). Interestingly, not all chromosomes exhibit the same dynamics during meiosis, which can lead to chromosome-specific behaviors and defects. This review will summarize some of the chromosome-specific meiotic events that are currently known and discuss their impact on meiotic outcomes.
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21
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Adilardi RS, Dernburg AF. Robust, versatile DNA FISH probes for chromosome-specific repeats in Caenorhabditis elegans and Pristionchus pacificus. G3 Genes|Genomes|Genetics 2022; 12:6585872. [PMID: 35567480 PMCID: PMC9258534 DOI: 10.1093/g3journal/jkac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/22/2022] [Indexed: 11/14/2022]
Abstract
Repetitive DNA sequences are useful targets for chromosomal fluorescence in situ hybridization. We analyzed recent genome assemblies of Caenorhabditis elegans and Pristionchus pacificus to identify tandem repeats with a unique genomic localization. Based on these findings, we designed and validated sets of oligonucleotide probes for each species targeting at least 1 locus per chromosome. These probes yielded reliable fluorescent signals in different tissues and can easily be combined with the immunolocalization of cellular proteins. Synthesis and labeling of these probes are highly cost-effective and require no hands-on labor. The methods presented here can be easily applied in other model and nonmodel organisms with a sequenced genome.
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Affiliation(s)
- Renzo S Adilardi
- Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, CA 94720-3220, USA
- Howard Hughes Medical Institute , Chevy Chase, MD 20815, USA
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley , Berkeley, CA 94720-3220, USA
- Howard Hughes Medical Institute , Chevy Chase, MD 20815, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory , Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences , Berkeley, CA 94720, USA
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22
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Haversat J, Woglar A, Klatt K, Akerib CC, Roberts V, Chen SY, Arur S, Villeneuve AM, Kim Y. Robust designation of meiotic crossover sites by CDK-2 through phosphorylation of the MutSγ complex. Proc Natl Acad Sci U S A 2022; 119:e2117865119. [PMID: 35576467 PMCID: PMC9173770 DOI: 10.1073/pnas.2117865119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/05/2022] [Indexed: 02/07/2023] Open
Abstract
Crossover formation is essential for proper segregation of homologous chromosomes during meiosis. Here, we show that Caenorhabditis elegans cyclin-dependent kinase 2 (CDK-2) partners with cyclin-like protein COSA-1 to promote crossover formation by promoting conversion of meiotic double-strand breaks into crossover–specific recombination intermediates. Further, we identify MutSγ component MSH-5 as a CDK-2 phosphorylation target. MSH-5 has a disordered C-terminal tail that contains 13 potential CDK phosphosites and is required to concentrate crossover–promoting proteins at recombination sites. Phosphorylation of the MSH-5 tail appears dispensable in a wild-type background, but when MutSγ activity is partially compromised, crossover formation and retention of COSA-1 at recombination sites are exquisitely sensitive to phosphosite loss. Our data support a model in which robustness of crossover designation reflects a positive feedback mechanism involving CDK-2–mediated phosphorylation and scaffold-like properties of the MSH5 C-terminal tail, features that combine to promote full recruitment and activity of crossover–promoting complexes.
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Affiliation(s)
- Jocelyn Haversat
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Alexander Woglar
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Kayla Klatt
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Chantal C. Akerib
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Victoria Roberts
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Shin-Yu Chen
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Swathi Arur
- Department of Genetics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
| | - Anne M. Villeneuve
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
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23
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Kim HJ, Liu C, Dernburg AF. How and Why Chromosomes Interact with the Cytoskeleton during Meiosis. Genes (Basel) 2022; 13:genes13050901. [PMID: 35627285 PMCID: PMC9140367 DOI: 10.3390/genes13050901] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/28/2022] Open
Abstract
During the early meiotic prophase, connections are established between chromosomes and cytoplasmic motors via a nuclear envelope bridge, known as a LINC (linker of nucleoskeleton and cytoskeleton) complex. These widely conserved links can promote both chromosome and nuclear motions. Studies in diverse organisms have illuminated the molecular architecture of these connections, but important questions remain regarding how they contribute to meiotic processes. Here, we summarize the current knowledge in the field, outline the challenges in studying these chromosome dynamics, and highlight distinctive features that have been characterized in major model systems.
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Affiliation(s)
- Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA;
| | - Chenshu Liu
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA;
| | - Abby F. Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA;
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA;
- Correspondence:
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24
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Banerjee RP, Srayko M. Sperm-specific glycogen synthase kinase 3 is required for sperm motility and the post-fertilization signal for female meiosis II in Caenorhabditis elegans. Development 2022; 149:275553. [DOI: 10.1242/dev.200229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/12/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
In most sexually reproducing animals, sperm entry provides the signal to initiate the final stages of female meiosis. In Caenorhabditis elegans, this signal is required for completion of female anaphase I and entry into meiosis II (MII). memi-1/2/3 (meiosis-to-mitosis) encode maternal components that facilitate this process; memi-1/2/3(RNAi) results in a skipped-MII phenotype. Previously, we used a gain-of-function mutation, memi-1(sb41), to identify genetic suppressors that represent candidates for the sperm-delivered signal. Herein, we characterize two suppressors of memi-1(sb41): gskl-1 and gskl-2. Both genes encode functionally redundant sperm glycogen synthase kinase, type 3 (GSK3) protein kinases. Loss of both genes causes defects in male spermatogenesis, sperm pseudopod treadmilling and paternal-effect embryonic lethality. The two kinases locate within the pseudopod of activated sperm, suggesting that they directly or indirectly regulate the sperm cytoskeletal polymer major sperm protein (MSP). The GSK3 genes genetically interact with another memi-1(sb41) suppressor, gsp-4, which encodes a sperm-specific PP1 phosphatase, previously proposed to regulate MSP dynamics. Moreover, gskl-2 gsp-4; gskl-1 triple mutants often skip female MII, similar to memi-1/2/3(RNAi). The GSK3 kinases and PP1 phosphatases perform similar sperm-related functions and work together for post-fertilization functions in the oocyte that involve MEMI.
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Affiliation(s)
| | - Martin Srayko
- University of Alberta Department of Biological Sciences , , Edmonton, AB T6G 2E9 , Canada
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25
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Abstract
The nematode Caenorhabditis elegans has shed light on many aspects of eukaryotic biology, including genetics, development, cell biology, and genomics. A major factor in the success of C. elegans as a model organism has been the availability, since the late 1990s, of an essentially gap-free and well-annotated nuclear genome sequence, divided among 6 chromosomes. In this review, we discuss the structure, function, and biology of C. elegans chromosomes and then provide a general perspective on chromosome biology in other diverse nematode species. We highlight malleable chromosome features including centromeres, telomeres, and repetitive elements, as well as the remarkable process of programmed DNA elimination (historically described as chromatin diminution) that induces loss of portions of the genome in somatic cells of a handful of nematode species. An exciting future prospect is that nematode species may enable experimental approaches to study chromosome features and to test models of chromosome evolution. In the long term, fundamental insights regarding how speciation is integrated with chromosome biology may be revealed.
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Affiliation(s)
- Peter M Carlton
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Denver, CO 80045, USA.,RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Shawn Ahmed
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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26
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Davis MB, Jash E, Chawla B, Haines RA, Tushman LE, Troll R, Csankovszki G. Dual roles for nuclear RNAi Argonautes in Caenorhabditis elegans dosage compensation. Genetics 2022; 221:6540857. [PMID: 35234908 PMCID: PMC9071528 DOI: 10.1093/genetics/iyac033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/21/2022] [Indexed: 11/14/2022] Open
Abstract
Dosage compensation involves chromosome-wide gene regulatory mechanisms which impact higher order chromatin structure and are crucial for organismal health. Using a genetic approach, we identified Argonaute genes which promote dosage compensation in Caenorhabditis elegans. Dosage compensation in C. elegans hermaphrodites is initiated by the silencing of xol-1 and subsequent activation of the dosage compensation complex which binds to both hermaphrodite X chromosomes and reduces transcriptional output by half. A hallmark phenotype of dosage compensation mutants is decondensation of the X chromosomes. We characterized this phenotype in Argonaute mutants using X chromosome paint probes and fluorescence microscopy. We found that while nuclear Argonaute mutants hrde-1 and nrde-3, as well as mutants for the piRNA Argonaute prg-1, exhibit derepression of xol-1 transcripts, they also affect X chromosome condensation in a xol-1-independent manner. We also characterized the physiological contribution of Argonaute genes to dosage compensation using genetic assays and found that hrde-1 and nrde-3 contribute to healthy dosage compensation both upstream and downstream of xol-1.
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Affiliation(s)
- Michael B Davis
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Eshna Jash
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bahaar Chawla
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rebecca A Haines
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lillian E Tushman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ryan Troll
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Györgyi Csankovszki
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA,Corresponding author: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 1105 N. University Ave, Ann Arbor, MI 48109-1085, USA.
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27
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Priyadarshini M, Ni JZ, Vargas-Velazquez AM, Gu SG, Frøkjær-Jensen C. Reprogramming the piRNA pathway for multiplexed and transgenerational gene silencing in C. elegans. Nat Methods 2022; 19:187-94. [PMID: 35115715 DOI: 10.1038/s41592-021-01369-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 12/07/2021] [Indexed: 01/01/2023]
Abstract
Single-guide RNAs can target exogenous CRISPR-Cas proteins to unique DNA locations, enabling genetic tools that are efficient, specific and scalable. Here we show that short synthetic guide Piwi-interacting RNAs (piRNAs) (21-nucleotide sg-piRNAs) expressed from extrachromosomal transgenes can, analogously, reprogram the endogenous piRNA pathway for gene-specific silencing in the hermaphrodite germline, sperm and embryos of Caenorhabditis elegans. piRNA-mediated interference ('piRNAi') is more efficient than RNAi and can be multiplexed, and auxin-mediated degradation of the piRNA-specific Argonaute PRG-1 allows conditional gene silencing. Target-specific silencing results in decreased messenger RNA levels, amplification of secondary small interfering RNAs and repressive chromatin modifications. Short (300 base pairs) piRNAi transgenes amplified from arrayed oligonucleotide pools also induce silencing, potentially making piRNAi highly scalable. We show that piRNAi can induce transgenerational epigenetic silencing of two endogenous genes (him-5 and him-8). Silencing is inherited for four to six generations after target-specific sg-piRNAs are lost, whereas depleting PRG-1 leads to essentially permanent epigenetic silencing.
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28
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Liu Y, Zhao Q, Nie H, Zhang F, Fu T, Zhang Z, Qi F, Wang R, Zhou J, Gao J. SYP-5 regulates meiotic thermotolerance in Caenorhabditis elegans. J Mol Cell Biol 2021; 13:662-675. [PMID: 34081106 PMCID: PMC8648394 DOI: 10.1093/jmcb/mjab035] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/27/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
Meiosis produces the haploid gametes required by all sexually reproducing organisms, occurring in specific temperature ranges in different organisms. However, how meiotic thermotolerance is regulated remains largely unknown. Using the model organism Caenorhabditis elegans, here, we identified the synaptonemal complex (SC) protein SYP-5 as a critical regulator of meiotic thermotolerance. syp-5-null mutants maintained a high percentage of viable progeny at 20°C but produced significantly fewer viable progeny at 25°C, a permissive temperature in wild-type worms. Cytological analysis of meiotic events in the mutants revealed that while SC assembly and disassembly, as well as DNA double-strand break repair kinetics, were not affected by the elevated temperature, crossover designation, and bivalent formation were significantly affected. More severe homolog segregation errors were also observed at elevated temperature. A temperature switching assay revealed that late meiotic prophase events were not temperature-sensitive and that meiotic defects during pachytene stage were responsible for the reduced viability of syp-5 mutants at the elevated temperature. Moreover, SC polycomplex formation and hexanediol sensitivity analysis suggested that SYP-5 was required for the normal properties of the SC, and charge-interacting elements in SC components were involved in regulating meiotic thermotolerance. Together, these findings provide a novel molecular mechanism for meiotic thermotolerance regulation.
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Affiliation(s)
- Yuanyuan Liu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Qiuchen Zhao
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Hui Nie
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Fengguo Zhang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Tingting Fu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Zhenguo Zhang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Feifei Qi
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Ruoxi Wang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Jun Zhou
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
| | - Jinmin Gao
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan 250014, China
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29
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Liu H, Gordon SG, Rog O. Heterologous synapsis in C. elegans is regulated by meiotic double-strand breaks and crossovers. Chromosoma 2021; 130:237-250. [PMID: 34608541 PMCID: PMC8671313 DOI: 10.1007/s00412-021-00763-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
Alignment of the parental chromosomes during meiotic prophase is key to the formation of genetic exchanges, or crossovers, and consequently to the successful production of gametes. In almost all studied organisms, alignment involves synapsis: the assembly of a conserved inter-chromosomal interface called the synaptonemal complex (SC). While the SC usually synapses homologous sequences, it can assemble between heterologous sequences. However, little is known about the regulation of heterologous synapsis. Here, we study the dynamics of heterologous synapsis in the nematode C. elegans. We characterize two experimental scenarios: SC assembly onto a folded-back chromosome that cannot pair with its homologous partner; and synapsis of pseudo-homologs, a fusion chromosome partnering with an unfused chromosome half its size. We observed elevated levels of heterologous synapsis when the number of meiotic double-strand breaks or crossovers were reduced, indicating that the promiscuity of synapsis is regulated by break formation or repair. In addition, our data suggests the existence of both chromosome-specific and nucleus-wide regulation on heterologous synapsis.
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Affiliation(s)
- Hanwenheng Liu
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112-0840, USA
- The Division of Biology & Biomedical Sciences, Washington University in St. Louis, 660 South Euclid Avenue, Missouri, 63110, USA
| | - Spencer G Gordon
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112-0840, USA
| | - Ofer Rog
- School of Biological Sciences and Center for Cell and Genome Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112-0840, USA.
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30
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Fielder SM, Kent T, Ling H, Gleason EJ, Kelly WG. A motor independent requirement for Dynein light chain in C. elegans meiotic synapsis. Genetics 2021; 220:6426083. [PMID: 34788833 DOI: 10.1093/genetics/iyab203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/29/2021] [Indexed: 11/15/2022] Open
Abstract
The dynein motor complex is thought to aid in homolog pairing in many organisms by moving chromosomes within the nuclear periphery to promote and test homologous interactions. This precedes synaptonemal complex (SC) formation during homolog synapsis, which stabilizes homolog proximity during recombination. We observed that depletion of the dynein light chain (DLC-1) in Caenorhabditis elegans irreversibly prevents synapsis, causing an increase in off-chromatin formation of SC protein foci with increasing temperature. This requirement for DLC-1 is independent of its function in dynein motors, as SYP protein foci do not form with depletion of other dynein motor components. In contrast to normal SC-related structures, foci formed with DLC-1 depletion are resistant to dissolution with 1,6-hexanediol, similar to aggregates of SC proteins formed in high growth temperatures. Dynein light chains have been shown to act as hub proteins that interact with other proteins through a conserved binding motif. We identified a similar DLC-1 binding motif in the C. elegans SC protein SYP-2, and mutation of the putative motif causes meiosis defects that are exacerbated by elevated temperatures. We propose that DLC-1 acts as a pre-synapsis chaperone-like factor for SYP proteins to help regulate their self-association prior to the signals for SC assembly, a role that is revealed by its increased essentiality at elevated temperatures.
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Affiliation(s)
- Sara M Fielder
- Biology Department, Emory University, Atlanta, Georgia 30322, USA.,Program in Genetics and Molecular Biology, Emory University, Atlanta, Georgia 30322, USA
| | - Tori Kent
- Biology Department, Emory University, Atlanta, Georgia 30322, USA
| | - Huiping Ling
- Biology Department, Emory University, Atlanta, Georgia 30322, USA
| | | | - William G Kelly
- Biology Department, Emory University, Atlanta, Georgia 30322, USA
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31
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Devigne A, Bhalla N. Mad1's ability to interact with Mad2 is essential to regulate and monitor meiotic synapsis in C. elegans. PLoS Genet 2021; 17:e1009598. [PMID: 34762652 DOI: 10.1371/journal.pgen.1009598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 11/23/2021] [Accepted: 10/11/2021] [Indexed: 11/19/2022] Open
Abstract
Meiotic homolog synapsis is essential to ensure accurate segregation of chromosomes during meiosis. In C. elegans, proper regulation of synapsis and a checkpoint that monitors synapsis relies on the spindle checkpoint components, Mad1 and Mad2, and Pairing Centers (PCs), cis-acting loci that interact with the nuclear envelope to mobilize chromosomes within the nucleus. Here, we test what specific functions of Mad1 and Mad2 are required to regulate and monitor synapsis. We find that a mutation that prevents Mad1's localization to the nuclear periphery abolishes the synapsis checkpoint but has no effect on Mad2's localization to the nuclear periphery or synapsis. By contrast, a mutation that prevents Mad1's interaction with Mad2 abolishes the synapsis checkpoint, delays synapsis and fails to localize Mad2 to the nuclear periphery. These data indicate that Mad1's primary role in regulating synapsis is through control of Mad2 and that Mad2 can bind other factors at the nuclear periphery. We also tested whether Mad2's ability to adopt a specific conformation associated with its activity during spindle checkpoint function is required for its role in meiosis. A mutation that prevents Mad2 from adopting its active conformer fails to localize to the nuclear periphery, abolishes the synapsis checkpoint and exhibits substantial defects in meiotic synapsis. Thus, Mad2, and its regulation by Mad1, is an important regulator of meiotic synapsis in C. elegans.
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32
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Abstract
The specialized two-stage meiotic cell division program halves a cell's chromosome complement in preparation for sexual reproduction. This reduction in ploidy requires that in meiotic prophase, each pair of homologous chromosomes (homologs) identify one another and form physical links through DNA recombination. Here, we review recent advances in understanding the complex morphological changes that chromosomes undergo during meiotic prophase to promote homolog identification and crossing over. We focus on the structural maintenance of chromosomes (SMC) family cohesin complexes and the meiotic chromosome axis, which together organize chromosomes and promote recombination. We then discuss the architecture and dynamics of the conserved synaptonemal complex (SC), which assembles between homologs and mediates local and global feedback to ensure high fidelity in meiotic recombination. Finally, we discuss exciting new advances, including mechanisms for boosting recombination on particular chromosomes or chromosomal domains and the implications of a new liquid crystal model for SC assembly and structure. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Sarah N Ur
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA; ,
| | - Kevin D Corbett
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA; , .,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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33
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Rillo-Bohn R, Adilardi R, Mitros T, Avşaroğlu B, Stevens L, Köhler S, Bayes J, Wang C, Lin S, Baskevitch KA, Rokhsar DS, Dernburg AF. Analysis of meiosis in Pristionchus pacificus reveals plasticity in homolog pairing and synapsis in the nematode lineage. eLife 2021; 10:70990. [PMID: 34427184 PMCID: PMC8455136 DOI: 10.7554/elife.70990] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
Meiosis is conserved across eukaryotes yet varies in the details of its execution. Here we describe a new comparative model system for molecular analysis of meiosis, the nematode Pristionchus pacificus, a distant relative of the widely studied model organism Caenorhabditis elegans. P. pacificus shares many anatomical and other features that facilitate analysis of meiosis in C. elegans. However, while C. elegans has lost the meiosis-specific recombinase Dmc1 and evolved a recombination-independent mechanism to synapse its chromosomes, P. pacificus expresses both DMC-1 and RAD-51. We find that SPO-11 and DMC-1 are required for stable homolog pairing, synapsis, and crossover formation, while RAD-51 is dispensable for these key meiotic processes. RAD-51 and DMC-1 localize sequentially to chromosomes during meiotic prophase and show nonoverlapping functions. We also present a new genetic map for P. pacificus that reveals a crossover landscape very similar to that of C. elegans, despite marked divergence in the regulation of synapsis and crossing-over between these lineages.
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Affiliation(s)
- Regina Rillo-Bohn
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Renzo Adilardi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Therese Mitros
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Barış Avşaroğlu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Lewis Stevens
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Darwin Tree of Life Project, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Simone Köhler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Joshua Bayes
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Clara Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Sabrina Lin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - K Alienor Baskevitch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Daniel S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Energy Joint Genome Institute, Berkeley, United States.,Okinawa Institute of Science and Technology Graduate University, Onna, Japan.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, Berkeley, United States
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34
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Hinman AW, Yeh HY, Roelens B, Yamaya K, Woglar A, Bourbon HMG, Chi P, Villeneuve AM. Caenorhabditis elegans DSB-3 reveals conservation and divergence among protein complexes promoting meiotic double-strand breaks. Proc Natl Acad Sci U S A 2021; 118:e2109306118. [PMID: 34389685 PMCID: PMC8379965 DOI: 10.1073/pnas.2109306118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Meiotic recombination plays dual roles in the evolution and stable inheritance of genomes: Recombination promotes genetic diversity by reassorting variants, and it establishes temporary connections between pairs of homologous chromosomes that ensure their future segregation. Meiotic recombination is initiated by generation of double-strand DNA breaks (DSBs) by the conserved topoisomerase-like protein Spo11. Despite strong conservation of Spo11 across eukaryotic kingdoms, auxiliary complexes that interact with Spo11 complexes to promote DSB formation are poorly conserved. Here, we identify DSB-3 as a DSB-promoting protein in the nematode Caenorhabditis elegans Mutants lacking DSB-3 are proficient for homolog pairing and synapsis but fail to form crossovers. Lack of crossovers in dsb-3 mutants reflects a requirement for DSB-3 in meiotic DSB formation. DSB-3 concentrates in meiotic nuclei with timing similar to DSB-1 and DSB-2 (predicted homologs of yeast/mammalian Rec114/REC114), and DSB-1, DSB-2, and DSB-3 are interdependent for this localization. Bioinformatics analysis and interactions among the DSB proteins support the identity of DSB-3 as a homolog of MEI4 in conserved DSB-promoting complexes. This identification is reinforced by colocalization of pairwise combinations of DSB-1, DSB-2, and DSB-3 foci in structured illumination microscopy images of spread nuclei. However, unlike yeast Rec114, DSB-1 can interact directly with SPO-11, and in contrast to mouse REC114 and MEI4, DSB-1, DSB-2, and DSB-3 are not concentrated predominantly at meiotic chromosome axes. We speculate that variations in the meiotic program that have coevolved with distinct reproductive strategies in diverse organisms may contribute to and/or enable diversification of essential components of the meiotic machinery.
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Affiliation(s)
- Albert W Hinman
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
| | - Hsin-Yi Yeh
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Baptiste Roelens
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Kei Yamaya
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Alexander Woglar
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Henri-Marc G Bourbon
- Centre de Biologie Intégrative, Molecular, Cellular & Developmental Biology Unit, Université Fédérale de Toulouse, 31000 Toulouse, France
| | - Peter Chi
- Institute of Biochemical Sciences, National Taiwan University, Taipei 10617, Taiwan
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
| | - Anne M Villeneuve
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305
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35
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Rappaport Y, Achache H, Falk R, Murik O, Ram O, Tzur YB. Bisection of the X chromosome disrupts the initiation of chromosome silencing during meiosis in Caenorhabditis elegans. Nat Commun 2021; 12:4802. [PMID: 34376665 PMCID: PMC8355143 DOI: 10.1038/s41467-021-24815-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/01/2021] [Indexed: 01/04/2023] Open
Abstract
During meiosis, gene expression is silenced in aberrantly unsynapsed chromatin and in heterogametic sex chromosomes. Initiation of sex chromosome silencing is disrupted in meiocytes with sex chromosome-autosome translocations. To determine whether this is due to aberrant synapsis or loss of continuity of sex chromosomes, we engineered Caenorhabditis elegans nematodes with non-translocated, bisected X chromosomes. In early meiocytes of mutant males and hermaphrodites, X segments are enriched with euchromatin assembly markers and active RNA polymerase II staining, indicating active transcription. Analysis of RNA-seq data showed that genes from the X chromosome are upregulated in gonads of mutant worms. Contrary to previous models, which predicted that any unsynapsed chromatin is silenced during meiosis, our data indicate that unsynapsed X segments are transcribed. Therefore, our results suggest that sex chromosome chromatin has a unique character that facilitates its meiotic expression when its continuity is lost, regardless of whether or not it is synapsed.
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Affiliation(s)
- Yisrael Rappaport
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hanna Achache
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Roni Falk
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Omer Murik
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Oren Ram
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yonatan B Tzur
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
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León-Periñán D, Fernández-Álvarez A. ChroMo, an Application for Unsupervised Analysis of Chromosome Movements in Meiosis. Cells 2021; 10:2013. [PMID: 34440781 DOI: 10.3390/cells10082013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/03/2022] Open
Abstract
Nuclear movements during meiotic prophase, driven by cytoskeleton forces, are a broadly conserved mechanism in opisthokonts and plants to promote pairing between homologous chromosomes. These forces are transmitted to the chromosomes by specific associations between telomeres and the nuclear envelope during meiotic prophase. Defective chromosome movements (CMs) harm pairing and recombination dynamics between homologues, thereby affecting faithful gametogenesis. For this reason, modelling the behaviour of CMs and their possible microvariations as a result of mutations or physico-chemical stress is important to understand this crucial stage of meiosis. Current developments in high-throughput imaging and image processing are yielding large CM datasets that are suitable for data mining approaches. To facilitate adoption of data mining pipelines, we present ChroMo, an interactive, unsupervised cloud application specifically designed for exploring CM datasets from live imaging. ChroMo contains a wide selection of algorithms and visualizations for time-series segmentation, motif discovery, and assessment of causality networks. Using ChroMo to analyse meiotic CMs in fission yeast, we found previously undiscovered features of CMs and causality relationships between chromosome morphology and trajectory. ChroMo will be a useful tool for understanding the behaviour of meiotic CMs in yeast and other model organisms.
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Abstract
A central player in meiotic chromosome dynamics is the conserved Polo-like kinase (PLK) family. PLKs are dynamically localized to distinct structures during meiotic prophase and phosphorylate a diverse group of substrates to control homolog pairing, synapsis, and meiotic recombination. In a recent study, we uncovered the mechanisms that control the targeting of a meiosis-specific PLK-2 in C. elegans. In early meiotic prophase, PLK-2 localizes to special chromosome regions known as pairing centers and drives homolog pairing and synapsis. PLK-2 then relocates to the synaptonemal complex (SC) after crossover designation and mediates chromosome remodeling required for homolog separation. What controls this intricate targeting of PLK-2 in space and time? We discuss recent findings and remaining questions for the future.
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Affiliation(s)
| | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD
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38
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Van Goor J, Shakes DC, Haag ES. Fisher vs. the Worms: Extraordinary Sex Ratios in Nematodes and the Mechanisms that Produce Them. Cells 2021; 10:1793. [PMID: 34359962 PMCID: PMC8303164 DOI: 10.3390/cells10071793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 01/20/2023] Open
Abstract
Parker, Baker, and Smith provided the first robust theory explaining why anisogamy evolves in parallel in multicellular organisms. Anisogamy sets the stage for the emergence of separate sexes, and for another phenomenon with which Parker is associated: sperm competition. In outcrossing taxa with separate sexes, Fisher proposed that the sex ratio will tend towards unity in large, randomly mating populations due to a fitness advantage that accrues in individuals of the rarer sex. This creates a vast excess of sperm over that required to fertilize all available eggs, and intense competition as a result. However, small, inbred populations can experience selection for skewed sex ratios. This is widely appreciated in haplodiploid organisms, in which females can control the sex ratio behaviorally. In this review, we discuss recent research in nematodes that has characterized the mechanisms underlying highly skewed sex ratios in fully diploid systems. These include self-fertile hermaphroditism and the adaptive elimination of sperm competition factors, facultative parthenogenesis, non-Mendelian meiotic oddities involving the sex chromosomes, and environmental sex determination. By connecting sex ratio evolution and sperm biology in surprising ways, these phenomena link two "seminal" contributions of G. A. Parker.
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Affiliation(s)
- Justin Van Goor
- Department of Biology, University of Maryland, College Park, MD 20742, USA;
| | - Diane C. Shakes
- Department of Biology, William and Mary, Williamsburg, VA 23187, USA;
| | - Eric S. Haag
- Department of Biology, University of Maryland, College Park, MD 20742, USA;
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39
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Velkova M, Silva N, Dello Stritto MR, Schleiffer A, Barraud P, Hartl M, Jantsch V. Caenorhabditis elegans RMI2 functional homolog-2 (RMIF-2) and RMI1 (RMH-1) have both overlapping and distinct meiotic functions within the BTR complex. PLoS Genet 2021; 17:e1009663. [PMID: 34252074 PMCID: PMC8318279 DOI: 10.1371/journal.pgen.1009663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 07/28/2021] [Accepted: 06/11/2021] [Indexed: 12/23/2022] Open
Abstract
Homologous recombination is a high-fidelity repair pathway for DNA double-strand breaks employed during both mitotic and meiotic cell divisions. Such repair can lead to genetic exchange, originating from crossover (CO) generation. In mitosis, COs are suppressed to prevent sister chromatid exchange. Here, the BTR complex, consisting of the Bloom helicase (HIM-6 in worms), topoisomerase 3 (TOP-3), and the RMI1 (RMH-1 and RMH-2) and RMI2 scaffolding proteins, is essential for dismantling joint DNA molecules to form non-crossovers (NCOs) via decatenation. In contrast, in meiosis COs are essential for accurate chromosome segregation and the BTR complex plays distinct roles in CO and NCO generation at different steps in meiotic recombination. RMI2 stabilizes the RMI1 scaffolding protein, and lack of RMI2 in mitosis leads to elevated sister chromatid exchange, as observed upon RMI1 knockdown. However, much less is known about the involvement of RMI2 in meiotic recombination. So far, RMI2 homologs have been found in vertebrates and plants, but not in lower organisms such as Drosophila, yeast, or worms. We report the identification of the Caenorhabditis elegans functional homolog of RMI2, which we named RMIF-2. The protein shows a dynamic localization pattern to recombination foci during meiotic prophase I and concentration into recombination foci is mutually dependent on other BTR complex proteins. Comparative analysis of the rmif-2 and rmh-1 phenotypes revealed numerous commonalities, including in regulating CO formation and directing COs toward chromosome arms. Surprisingly, the prevalence of heterologous recombination was several fold lower in the rmif-2 mutant, suggesting that RMIF-2 may be dispensable or less strictly required for some BTR complex-mediated activities during meiosis. Bloom syndrome is caused by mutations in proteins of the BTR complex (consisting of the Bloom helicase, topoisomerase 3, and the RMI1 and RMI2 scaffolding proteins) and the clinical characteristics are growth deficiency, short stature, skin photosensitivity, and increased cancer predisposition. At the cellular level, characteristic features are the presence of increased sister chromatid exchange on chromosomes; unresolved DNA recombination intermediates that eventually cause genome instability; and erroneous DNA repair by heterologous recombination (recombination between non-identical sequences, extremely rare in wild type animals), which can trigger translocations and chromosomal rearrangements. Identification of the Caenorhabditis elegans ortholog of RMI2 (called RMIF-2) allowed us to compare heterologous recombination in the germline of mutants of various BTR complex proteins. The heterologous recombination rate was several fold lower in rmif-2 mutants than in mutants of rmh-1 and him-6 (worm homologs of RMI1 and the Bloom helicase, respectively). Nevertheless, many phenotypic features point at RMIF-2 working together with RMH-1. If these germline functions of RMI2/RMIF-2 are conserved in humans, this might mean that individuals with RMI2 mutations have a lower risk of translocations and genome rearrangements than those with mutations in the other BTR complex genes.
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Affiliation(s)
- Maria Velkova
- Department of Chromosome Biology, Max Perutz Labs, Vienna BioCenter, Vienna, Austria
| | - Nicola Silva
- Department of Chromosome Biology, Max Perutz Labs, Vienna BioCenter, Vienna, Austria
| | | | - Alexander Schleiffer
- Research Institute of Molecular Pathology, Campus Vienna BioCenter, Vienna 1, Vienna, Austria
- Institute of Molecular Biotechnology, Campus Vienna BioCenter, Vienna, Austria
| | - Pierre Barraud
- Expression Génétique Microbienne, UMR 8261, Centre national de la recherche scientifique, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Markus Hartl
- Mass Spectrometry Facility, Max Perutz Labs, Vienna BioCenter, Vienna, Austria
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Labs, Vienna BioCenter, Vienna, Austria
- * E-mail:
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40
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Child MB, Bateman JR, Jahangiri A, Reimer A, Lammers NC, Sabouni N, Villamarin D, McKenzie-Smith GC, Johnson JE, Jost D, Garcia HG. Live imaging and biophysical modeling support a button-based mechanism of somatic homolog pairing in Drosophila. eLife 2021; 10:64412. [PMID: 34100718 PMCID: PMC8294847 DOI: 10.7554/elife.64412] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
Three-dimensional eukaryotic genome organization provides the structural basis for gene regulation. In Drosophila melanogaster, genome folding is characterized by somatic homolog pairing, where homologous chromosomes are intimately paired from end to end; however, how homologs identify one another and pair has remained mysterious. Recently, this process has been proposed to be driven by specifically interacting 'buttons' encoded along chromosomes. Here, we turned this hypothesis into a quantitative biophysical model to demonstrate that a button-based mechanism can lead to chromosome-wide pairing. We tested our model using live-imaging measurements of chromosomal loci tagged with the MS2 and PP7 nascent RNA labeling systems. We show solid agreement between model predictions and experiments in the pairing dynamics of individual homologous loci. Our results strongly support a button-based mechanism of somatic homolog pairing in Drosophila and provide a theoretical framework for revealing the molecular identity and regulation of buttons.
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Affiliation(s)
- Myron Barber Child
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States
| | - Jack R Bateman
- Biology Department, Bowdoin College, Brunswick, United States
| | - Amir Jahangiri
- Univ Grenoble Alpes CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Armando Reimer
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Nicholas C Lammers
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Nica Sabouni
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | | | | | | | - Daniel Jost
- Univ Grenoble Alpes CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France.,Université de Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratory of Biology and Modeling of the Cell, Lyon, France
| | - Hernan G Garcia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States.,Institute for Quantitative Biosciences-QB3, University of California, Berkeley, Berkeley, United States
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41
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De-Castro ARG, Quintas-Gonçalves J, Silva-Ribeiro T, Rodrigues DRM, De-Castro MJG, Abreu CM, Dantas TJ. The IFT20 homolog in Caenorhabditis elegans is required for ciliogenesis and cilia-mediated behavior. MicroPubl Biol 2021; 2021. [PMID: 33997658 PMCID: PMC8114103 DOI: 10.17912/micropub.biology.000396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cilia are microtubule-based organelles that carry out a wide range of critical functions throughout the development of higher animals. Regardless of their type, all cilia rely on a motor-driven, bidirectional transport system known as intraflagellar transport (IFT). Of the many components of the IFT machinery, IFT20 is one of the smallest subunits. Nevertheless, IFT20 has been shown to play critical roles in the assembly of several types of mammalian cilia. Here we show that the IFT20 homolog in Caenorhabditis elegans, IFT-20, is also important for correct cilium assembly in sensory neurons. Strikingly, however, we find that IFT-20-deficient animals are able to assemble short, vestigial cilia. In spite of this, we show that practically all IFT-20-deficient animals fail to respond to environmental cues that are normally detected by cilia to modulate their behavior. Altogether, our results indicate that IFT-20 is critical for both the correct assembly and function of cilia in C. elegans.
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Affiliation(s)
- Ana R G De-Castro
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Joana Quintas-Gonçalves
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tiago Silva-Ribeiro
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Diogo R M Rodrigues
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Maria J G De-Castro
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Carla M Abreu
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tiago J Dantas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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42
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Brandt JN, Hussey KA, Kim Y. Spatial and temporal control of targeting Polo-like kinase during meiotic prophase. J Cell Biol 2021; 219:152136. [PMID: 32997737 PMCID: PMC7594494 DOI: 10.1083/jcb.202006094] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/19/2020] [Accepted: 08/28/2020] [Indexed: 12/17/2022] Open
Abstract
Polo-like kinases (PLKs) play widely conserved roles in orchestrating meiotic chromosome dynamics. However, how PLKs are targeted to distinct subcellular localizations during meiotic progression remains poorly understood. Here, we demonstrate that the cyclin-dependent kinase CDK-1 primes the recruitment of PLK-2 to the synaptonemal complex (SC) through phosphorylation of SYP-1 in C. elegans. SYP-1 phosphorylation by CDK-1 occurs just before meiotic onset. However, PLK-2 docking to the SC is prevented by the nucleoplasmic HAL-2/3 complex until crossover designation, which constrains PLK-2 to special chromosomal regions known as pairing centers to ensure proper homologue pairing and synapsis. PLK-2 is targeted to crossover sites primed by CDK-1 and spreads along the SC by reinforcing SYP-1 phosphorylation on one side of each crossover only when threshold levels of crossovers are generated. Thus, the integration of chromosome-autonomous signaling and a nucleus-wide crossover-counting mechanism partitions holocentric chromosomes relative to the crossover site, which ultimately defines the pattern of chromosome segregation during meiosis I.
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Affiliation(s)
- James N Brandt
- Department of Biology, Johns Hopkins University, Baltimore, MD
| | | | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD
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43
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Gordon SG, Kursel LE, Xu K, Rog O. Synaptonemal Complex dimerization regulates chromosome alignment and crossover patterning in meiosis. PLoS Genet 2021; 17:e1009205. [PMID: 33730019 PMCID: PMC7968687 DOI: 10.1371/journal.pgen.1009205] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 02/15/2021] [Indexed: 12/30/2022] Open
Abstract
During sexual reproduction the parental homologous chromosomes find each other (pair) and align along their lengths by integrating local sequence homology with large-scale contiguity, thereby allowing for precise exchange of genetic information. The Synaptonemal Complex (SC) is a conserved zipper-like structure that assembles between the homologous chromosomes, bringing them together and regulating exchanges between them. However, the molecular mechanisms by which the SC carries out these functions remain poorly understood. Here we isolated and characterized two mutations in the dimerization interface in the middle of the SC zipper in C. elegans. The mutations perturb both chromosome alignment and the regulation of genetic exchanges. Underlying the chromosome-scale phenotypes are distinct alterations to the way SC subunits interact with one another. We propose a model whereby the SC brings homologous chromosomes together through two activities: obligate zipping that prevents assembly on unpaired chromosomes; and a tendency to extend pairing interactions along the entire length of the chromosomes.
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Affiliation(s)
- Spencer G. Gordon
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Lisa E. Kursel
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Kewei Xu
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Ofer Rog
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
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44
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Zhang Z, Xie S, Wang R, Guo S, Zhao Q, Nie H, Liu Y, Zhang F, Chen M, Liu L, Meng X, Liu M, Zhao L, Colaiácovo MP, Zhou J, Gao J. Multivalent weak interactions between assembly units drive synaptonemal complex formation. J Cell Biol 2021; 219:151585. [PMID: 32211900 PMCID: PMC7199860 DOI: 10.1083/jcb.201910086] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/22/2020] [Accepted: 02/26/2020] [Indexed: 12/28/2022] Open
Abstract
The synaptonemal complex (SC) is an ordered but highly dynamic structure assembled between homologous chromosomes to control interhomologous crossover formation, ensuring accurate meiotic chromosome segregation. However, the mechanisms regulating SC assembly and dynamics remain unclear. Here, we identified two new SC components, SYP-5 and SYP-6, in Caenorhabditis elegans that have distinct expression patterns and form distinct SC assembly units with other SYPs through stable interactions. SYP-5 and SYP-6 exhibit diverse in vivo SC regulatory functions and distinct phase separation properties in cells. Charge-interacting elements (CIEs) are enriched in SC intrinsically disordered regions (IDRs), and IDR deletion or CIE removal confirmed a requirement for these elements in SC regulation. Our data support the theory that multivalent weak interactions between the SC units drive SC formation and that CIEs confer multivalency to the assembly units.
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Affiliation(s)
- Zhenguo Zhang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Songbo Xie
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Ruoxi Wang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Shuqun Guo
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Qiuchen Zhao
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Hui Nie
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Yuanyuan Liu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Fengguo Zhang
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Miao Chen
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Libo Liu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Xiaoqian Meng
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Min Liu
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
| | - Li Zhao
- Department of Pathology, Harvard Medical School, Dana-Farber/Harvard Cancer Center, Boston, MA.,Department of Laboratory Medicine, Children's Hospital Boston, Boston, MA
| | | | - Jun Zhou
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China.,State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Jinmin Gao
- Institute of Biomedical Sciences, College of Life Sciences, Key Laboratory of Animal Resistance Biology of Shandong Province, Shandong Normal University, Jinan, Shandong, China
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45
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Wong X, Loo TH, Stewart CL. LINC complex regulation of genome organization and function. Curr Opin Genet Dev 2021; 67:130-41. [PMID: 33524904 DOI: 10.1016/j.gde.2020.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/25/2020] [Accepted: 12/11/2020] [Indexed: 12/28/2022]
Abstract
The regulation of genomic function is in part mediated through the physical organization and architecture of the nucleus. Disruption to nuclear organization and architecture is increasingly being recognized by its contribution to many diseases. The LINC complexes - protein structures traversing the nuclear envelope, that physically connect the nuclear interior, and hence the genome, to cytoplasmic cytoskeletal networks are an important component in the physical organization of the genome and its function. This connection, potentially allows for the constant detection of environmental mechanical stimuli, resulting in altered regulation of nuclear architecture and genome function, either directly or via the process of mechanotransduction. Here, we review the influences LINC complexes exert on genome functions and their impact on cellular/organismal health.
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46
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Clark JN, Prajapati G, Aldaco FK, Sokolich TJ, Keung SS, Austin SP, Valdés ÁA, LaMunyon CW. Functionally non-redundant paralogs spe-47 and spe-50 encode FB-MO associated proteins and interact with him-8. PLoS One 2020; 15:e0230939. [PMID: 33382704 PMCID: PMC7774929 DOI: 10.1371/journal.pone.0230939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 12/10/2020] [Indexed: 11/25/2022] Open
Abstract
The activation of C. elegans spermatids to crawling spermatozoa is affected by a number of genes including spe-47. Here, we investigate a paralog to spe-47: spe-50, which has a highly conserved sequence and expression, but which is not functionally redundant to spe-47. Phylogenetic analysis indicates that the duplication event that produced the paralogs occurred prior to the radiation of the Caenorhabditis species included in the analysis, allowing a long period for the paralogs to diverge in function. Furthermore, we observed that knockout mutations in both genes, either alone or together, have little effect on sperm function. However, hermaphrodites harboring both knockout mutations combined with a third mutation in the him-8 gene are nearly self-sterile due to a sperm defect, even though they have numerous apparently normal sperm within their spermathecae. We suggest that the sperm in these triple mutants are defective in fusing with oocytes, and that the effect of the him-8 mutation is unclear but likely due to its direct or indirect effect on local chromatin structure and function.
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Affiliation(s)
- Jessica N. Clark
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Gaurav Prajapati
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Fermina K. Aldaco
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Thomas J. Sokolich
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Steven S. Keung
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Sarojani P. Austin
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Ángel A. Valdés
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
| | - Craig W. LaMunyon
- Department of Biological Sciences, Cal Poly Pomona, Pomona, California, United States of America
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47
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Uebel CJ, Agbede D, Wallis DC, Phillips CM. Mutator Foci Are Regulated by Developmental Stage, RNA, and the Germline Cell Cycle in Caenorhabditis elegans. G3 (Bethesda) 2020; 10:3719-3728. [PMID: 32763952 PMCID: PMC7534428 DOI: 10.1534/g3.120.401514] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/03/2020] [Indexed: 02/02/2023]
Abstract
RNA interference is a crucial gene regulatory mechanism in Caenorhabditis elegans Phase-separated perinuclear germline compartments called Mutator foci are a key element of RNAi, ensuring robust gene silencing and transgenerational epigenetic inheritance. Despite their importance, Mutator foci regulation is not well understood, and observations of Mutator foci have been largely limited to adult hermaphrodite germlines. Here we reveal that punctate Mutator foci arise in the progenitor germ cells of early embryos and persist throughout all larval stages. They are additionally present throughout the male germline and in the cytoplasm of post-meiotic spermatids, suggestive of a role in paternal epigenetic inheritance. In the adult germline, transcriptional inhibition results in a pachytene-specific loss of Mutator foci, indicating that Mutator foci are partially reliant on RNA for their stability. Finally, we demonstrate that Mutator foci intensity is modulated by the stage of the germline cell cycle and specifically, that Mutator foci are brightest and most robust in the mitotic cells, transition zone, and late pachytene of adult germlines. Thus, our data defines several new factors that modulate Mutator foci morphology which may ultimately have implications for efficacy of RNAi in certain cell stages or environments.
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Affiliation(s)
- Celja J Uebel
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Dana Agbede
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Dylan C Wallis
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
| | - Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089
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Lascarez-Lagunas LI, Herruzo E, Grishok A, San-Segundo PA, Colaiácovo MP. DOT-1.1-dependent H3K79 methylation promotes normal meiotic progression and meiotic checkpoint function in C. elegans. PLoS Genet 2020; 16:e1009171. [PMID: 33104701 PMCID: PMC7644094 DOI: 10.1371/journal.pgen.1009171] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 11/05/2020] [Accepted: 10/06/2020] [Indexed: 01/02/2023] Open
Abstract
Epigenetic modifiers are emerging as important regulators of the genome. However, how they regulate specific processes during meiosis is not well understood. Methylation of H3K79 by the histone methyltransferase Dot1 has been shown to be involved in the maintenance of genomic stability in various organisms. In S. cerevisiae, Dot1 modulates the meiotic checkpoint response triggered by synapsis and/or recombination defects by promoting Hop1-dependent Mek1 activation and Hop1 distribution along unsynapsed meiotic chromosomes, at least in part, by regulating Pch2 localization. However, how this protein regulates meiosis in metazoans is unknown. Here, we describe the effects of H3K79me depletion via analysis of dot-1.1 or zfp-1 mutants during meiosis in Caenorhabditis elegans. We observed decreased fertility and increased embryonic lethality in dot-1.1 mutants suggesting meiotic dysfunction. We show that DOT-1.1 plays a role in the regulation of pairing, synapsis and recombination in the worm. Furthermore, we demonstrate that DOT-1.1 is an important regulator of mechanisms surveilling chromosome synapsis during meiosis. In sum, our results reveal that regulation of H3K79me plays an important role in coordinating events during meiosis in C. elegans.
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Affiliation(s)
- Laura I. Lascarez-Lagunas
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, United States of America
| | - Esther Herruzo
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and University of Salamanca, Salamanca, Spain
| | - Alla Grishok
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, United States of America
- Genome Science Institute, Boston University School of Medicine, Boston, MA, United States of America
| | - Pedro A. San-Segundo
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas and University of Salamanca, Salamanca, Spain
| | - Mónica P. Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, United States of America
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Li Q, Hariri S, Engebrecht J. Meiotic Double-Strand Break Processing and Crossover Patterning Are Regulated in a Sex-Specific Manner by BRCA1-BARD1 in Caenorhabditis elegans. Genetics 2020; 216:359-379. [PMID: 32796008 PMCID: PMC7536853 DOI: 10.1534/genetics.120.303292] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/08/2020] [Indexed: 12/29/2022] Open
Abstract
Meiosis is regulated in a sex-specific manner to produce two distinct gametes, sperm and oocytes, for sexual reproduction. To determine how meiotic recombination is regulated in spermatogenesis, we analyzed the meiotic phenotypes of mutants in the tumor suppressor E3 ubiquitin ligase BRC-1-BRD-1 complex in Caenorhabditis elegans male meiosis. Unlike in mammals, this complex is not required for meiotic sex chromosome inactivation, the process whereby hemizygous sex chromosomes are transcriptionally silenced. Interestingly, brc-1 and brd-1 mutants show meiotic recombination phenotypes that are largely opposing to those previously reported for female meiosis. Fewer meiotic recombination intermediates marked by the recombinase RAD-51 were observed in brc-1 and brd-1 mutants, and the reduction in RAD-51 foci could be suppressed by mutation of nonhomologous-end-joining proteins. Analysis of GFP::RPA-1 revealed fewer foci in the brc-1brd-1 mutant and concentration of BRC-1-BRD-1 to sites of meiotic recombination was dependent on DNA end resection, suggesting that the complex regulates the processing of meiotic double-strand breaks to promote repair by homologous recombination. Further, BRC-1-BRD-1 is important to promote progeny viability when male meiosis is perturbed by mutations that block the pairing and synapsis of different chromosome pairs, although the complex is not required to stabilize the RAD-51 filament as in female meiosis under the same conditions. Analyses of crossover designation and formation revealed that BRC-1-BRD-1 inhibits supernumerary COs when meiosis is perturbed. Together, our findings suggest that BRC-1-BRD-1 regulates different aspects of meiotic recombination in male and female meiosis.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
| | - Sara Hariri
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
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Giacopazzi S, Vong D, Devigne A, Bhalla N. PCH-2 collaborates with CMT-1 to proofread meiotic homolog interactions. PLoS Genet 2020; 16:e1008904. [PMID: 32730253 DOI: 10.1371/journal.pgen.1008904] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 08/18/2020] [Accepted: 06/01/2020] [Indexed: 11/19/2022] Open
Abstract
The conserved ATPase, PCH-2/TRIP13, is required during both the spindle checkpoint and meiotic prophase. However, its specific role in regulating meiotic homolog pairing, synapsis and recombination has been enigmatic. Here, we report that this enzyme is required to proofread meiotic homolog interactions. We generated a mutant version of PCH-2 in C. elegans that binds ATP but cannot hydrolyze it: pch-2E253Q. In vitro, this mutant can bind a known substrate but is unable to remodel it. This mutation results in some non-homologous synapsis and impaired crossover assurance. Surprisingly, worms with a null mutation in PCH-2's adapter protein, CMT-1, the ortholog of p31comet, localize PCH-2 to meiotic chromosomes, exhibit non-homologous synapsis and lose crossover assurance. The similarity in phenotypes between cmt-1 and pch-2E253Q mutants suggest that PCH-2 can bind its meiotic substrates in the absence of CMT-1, in contrast to its role during the spindle checkpoint, but requires its adapter to hydrolyze ATP and remodel them.
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