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Owens DA, Butler AM, Aguero TH, Newman KM, Van Booven D, King ML. High-throughput analysis reveals novel maternal germline RNAs crucial for primordial germ cell preservation and proper migration. Development 2017; 144:292-304. [PMID: 28096217 DOI: 10.1242/dev.139220] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 11/25/2016] [Indexed: 01/10/2023]
Abstract
During oogenesis, hundreds of maternal RNAs are selectively localized to the animal or vegetal pole, including determinants of somatic and germline fates. Although microarray analysis has identified localized determinants, it is not comprehensive and is limited to known transcripts. Here, we utilized high-throughput RNA-sequencing analysis to comprehensively interrogate animal and vegetal pole RNAs in the fully grown Xenopus laevis oocyte. We identified 411 (198 annotated) and 27 (15 annotated) enriched mRNAs at the vegetal and animal pole, respectively. Ninety were novel mRNAs over 4-fold enriched at the vegetal pole and six were over 10-fold enriched at the animal pole. Unlike mRNAs, microRNAs were not asymmetrically distributed. Whole-mount in situ hybridization confirmed that all 17 selected mRNAs were localized. Biological function and network analysis of vegetally enriched transcripts identified protein-modifying enzymes, receptors, ligands, RNA-binding proteins, transcription factors and co-factors with five defining hubs linking 47 genes in a network. Initial functional studies of maternal vegetally localized mRNAs show that sox7 plays a novel and important role in primordial germ cell (PGC) development and that ephrinB1 (efnb1) is required for proper PGC migration. We propose potential pathways operating at the vegetal pole that highlight where future investigations might be most fruitful.
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Affiliation(s)
- Dawn A Owens
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Amanda M Butler
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Tristan H Aguero
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Karen M Newman
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Derek Van Booven
- The Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
| | - Mary Lou King
- Department of Cell Biology, University of Miami Miller School of Medicine, 1011 NW 15th St, Miami, FL 33136, USA
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Shimaoka K, Mukumoto Y, Tanigawa Y, Komiya T. Xenopus Vasa Homolog XVLG1 is Essential for Migration and Survival of Primordial Germ Cells. Zoolog Sci 2017; 34:93-104. [PMID: 28397605 DOI: 10.2108/zs160198] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Xenopus vasa-like gene 1 (XVLG1), a DEAD-Box Helicase 4 (DDX4) gene identified as a vertebrate vasa homologue, is required for the formation of primordial germ cells (PGCs). However, it remains to be clarified when and how XVLG1 functions in the formation of the germ cells. To gain a better understanding of the molecular mechanisms underlying XVLG1 during PGC development, we injected XVLG1 morpholino oligos into germ-plasm containing blastomeres of 32-cell stage of Xenopus embryos, and traced cell fates of the injected blastomere-derived PGCs. As a result of this procedure, migration of the PGCs was impaired and the number of PGCs derived from the blastomeres was significantly decreased. In addition, TUNEL staining in combination with in situ hybridization revealed that the loss of PGCs peaked at stage 27 was caused by apoptosis. This data strongly suggests an essential role for XVLG1 in migration and survival of the germ cells.
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Affiliation(s)
- Kazumi Shimaoka
- 1 Department of Biological Function, Faculty of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-0022, Japan
| | - Yoshiko Mukumoto
- 1 Department of Biological Function, Faculty of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-0022, Japan.,2 Genetic Engineering Team, RIKEN Center for Life Science Technologies, Minatojimaminamimachi, Chuou-ku, Kobe 650-0047, Japan
| | - Yoko Tanigawa
- 1 Department of Biological Function, Faculty of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-0022, Japan
| | - Tohru Komiya
- 1 Department of Biological Function, Faculty of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-0022, Japan
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Butler AM, Aguero T, Newman KM, King ML. Primordial Germ Cell Isolation from Xenopus laevis Embryos. Methods Mol Biol 2017; 1463:115-124. [PMID: 27734352 DOI: 10.1007/978-1-4939-4017-2_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Primordial germ cells (PGCs) are the precursors to the gametes and have the unique ability to retain full developmental potential. However, the mechanism(s) and gene-network(s) necessary for their proper specification and development are poorly understood. This is due, in part, to the challenges that must be overcome in order to identify and isolate PGCs during critical stages of development. Two distinct mechanisms have been characterized to specify the germ cell lineage in vertebrates: induction and inheritance. Regardless of mechanism, there are common developmental features shared among all vertebrates in forming the germ cell lineage. Xenopus offers several advantages for understanding the molecular mechanisms necessary to establish the germ line. Here, we provide detailed methods for isolating live PGCs at different time points: 1) just after they have segregated from the endodermal lineage, and 2) while they are migrating towards the presumptive gonad. Isolation of PGCs at these critical developmental stages will allow for the investigation of the mechanism(s) and gene-network(s) necessary for their proper specification and development.
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Affiliation(s)
- Amanda M Butler
- Department of Cell Biology, University of Miami Miller School of Medicine, 1600 NW 10 Ave, Miami, FL, 33136, USA
| | - Tristan Aguero
- Department of Cell Biology, University of Miami Miller School of Medicine, 1600 NW 10 Ave, Miami, FL, 33136, USA
| | - Karen M Newman
- Department of Cell Biology, University of Miami Miller School of Medicine, 1600 NW 10 Ave, Miami, FL, 33136, USA
| | - Mary Lou King
- Department of Cell Biology, University of Miami Miller School of Medicine, 1600 NW 10 Ave, Miami, FL, 33136, USA.
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Rosa A, Brivanlou AH. Role of MicroRNAs in Zygotic Genome Activation: Modulation of mRNA During Embryogenesis. Methods Mol Biol 2017; 1605:31-43. [PMID: 28456956 DOI: 10.1007/978-1-4939-6988-3_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A fundamental process occurring during early development is the zygotic genome activation, i.e., the initiation of transcription from the embryonic genome. Before that step, cellular processes in the developing embryo are dictated by transcripts produced by the maternal genome and accumulated in the egg during oogenesis. The maternal-to-zygotic transition (MZT) involves both the clearance of maternal RNAs and the initiation of transcription of the embryonic genome and is a tightly regulated process. In some species, decay of maternal transcripts may be facilitated by the activity of microRNAs. These small RNAs can act pleiotropically, blocking translation and inducing destabilization of hundreds of different maternal targets. In this review, we will discuss the role of microRNAs during MZT, focusing on Drosophila melanogaster and vertebrate models, Xenopus laevis, Zebrafish and mouse, in which such a mechanism has been more extensively studied.
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Affiliation(s)
- Alessandro Rosa
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, Rome, 00185, Italy
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, 1230 York Ave., New York, NY, 10065, USA
| | - Ali H Brivanlou
- Laboratory of Molecular Vertebrate Embryology, The Rockefeller University, 1230 York Ave., New York, NY, 10065, USA.
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Dallaire A, Simard MJ. The implication of microRNAs and endo-siRNAs in animal germline and early development. Dev Biol 2016; 416:18-25. [PMID: 27287880 DOI: 10.1016/j.ydbio.2016.06.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/31/2016] [Accepted: 06/06/2016] [Indexed: 01/13/2023]
Abstract
Germ cells provide maternal mRNAs that are stored in the oocyte, and later translated at a specific time of development. In this context, gene regulation depends mainly on post-transcriptional mechanisms that contribute to keep maternal transcripts in a stable and translationally silent state. In recent years, small non-coding RNAs, such as microRNAs have emerged as key post-transcriptional regulators of gene expression. microRNAs control the translation efficiency and/or stability of targeted mRNAs. microRNAs are present in animal germ cells and maternally inherited microRNAs are abundant in early embryos. However, it is not known how microRNAs control the stability and translation of maternal transcripts. In this review, we will discuss the implication of germline microRNAs in regulating animal oogenesis and early embryogenesis as well as compare their roles with endo-siRNAs, small RNA species that share key molecular components with the microRNA pathway.
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Affiliation(s)
- Alexandra Dallaire
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6
| | - Martin J Simard
- St-Patrick Research Group in Basic Oncology, Centre Hospitalier Universitaire de Québec-Université Laval Research Centre (Hôtel-Dieu de Québec), Quebec City, Québec, Canada G1R 2J6; Laval University Cancer Research Centre, Quebec City, Québec, Canada G1R 2J6.
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MicroRNAs: From Female Fertility, Germ Cells, and Stem Cells to Cancer in Humans. Stem Cells Int 2015; 2016:3984937. [PMID: 26664407 PMCID: PMC4655303 DOI: 10.1155/2016/3984937] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/19/2015] [Indexed: 12/14/2022] Open
Abstract
MicroRNAs are a family of naturally occurring small noncoding RNA molecules that play an important regulatory role in gene expression. They are suggested to regulate a large proportion of protein encoding genes by mediating the translational suppression and posttranscriptional control of gene expression. Recent findings show that microRNAs are emerging as important regulators of cellular differentiation and dedifferentiation, and are deeply involved in developmental processes including human preimplantation development. They keep a balance between pluripotency and differentiation in the embryo and embryonic stem cells. Moreover, it became evident that dysregulation of microRNA expression may play a fundamental role in progression and dissemination of different cancers including ovarian cancer. The interest is still increased by the discovery of exosomes, that is, cell-derived vesicles, which can carry different proteins but also microRNAs between different cells and are involved in cell-to-cell communication. MicroRNAs, together with exosomes, have a great potential to be used for prognosis, therapy, and biomarkers of different diseases including infertility. The aim of this review paper is to summarize the existent knowledge on microRNAs related to female fertility and cancer: from primordial germ cells and ovarian function, germinal stem cells, oocytes, and embryos to embryonic stem cells.
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Claußen M, Lingner T, Pommerenke C, Opitz L, Salinas G, Pieler T. Global analysis of asymmetric RNA enrichment in oocytes reveals low conservation between closely related Xenopus species. Mol Biol Cell 2015; 26:3777-87. [PMID: 26337391 PMCID: PMC4626063 DOI: 10.1091/mbc.e15-02-0115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 08/28/2015] [Indexed: 12/27/2022] Open
Abstract
Subcellular localization of mRNAs contributes to the generation of cellular asymmetries and cell fate determination. A comparative global analysis is given of animally and vegetally enriched RNAs in oocytes from two closely related Xenopus species. RNAs that localize to the vegetal cortex during Xenopus laevis oogenesis have been reported to function in germ layer patterning, axis determination, and development of the primordial germ cells. Here we report on the genome-wide, comparative analysis of differentially localizing RNAs in Xenopus laevis and Xenopus tropicalis oocytes, revealing a surprisingly weak degree of conservation in respect to the identity of animally as well as vegetally enriched transcripts in these closely related species. Heterologous RNA injections and protein binding studies indicate that the different RNA localization patterns in these two species are due to gain/loss of cis-acting localization signals rather than to differences in the RNA-localizing machinery.
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Affiliation(s)
- Maike Claußen
- Institute of Developmental Biochemistry, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Thomas Lingner
- Microarray and Deep-Sequencing Core Facility, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Claudia Pommerenke
- Microarray and Deep-Sequencing Core Facility, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Lennart Opitz
- Microarray and Deep-Sequencing Core Facility, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Gabriela Salinas
- Microarray and Deep-Sequencing Core Facility, University Medical Center Göttingen, 37077 Göttingen, Germany
| | - Tomas Pieler
- Institute of Developmental Biochemistry, University Medical Center Göttingen, 37077 Göttingen, Germany
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Yang J, Aguero T, King ML. The Xenopus Maternal-to-Zygotic Transition from the Perspective of the Germline. Curr Top Dev Biol 2015; 113:271-303. [PMID: 26358876 DOI: 10.1016/bs.ctdb.2015.07.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In Xenopus, the germline is specified by the inheritance of germ-plasm components synthesized at the beginning of oogenesis. Only the cells in the early embryo that receive germ plasm, the primordial germ cells (PGCs), are competent to give rise to the gametes. Thus, germ-plasm components continue the totipotent potential exhibited by the oocyte into the developing embryo at a time when most cells are preprogrammed for somatic differentiation as dictated by localized maternal determinants. When zygotic transcription begins at the mid-blastula transition, the maternally set program for somatic differentiation is realized. At this time, genetic control is ceded to the zygotic genome, and developmental potential gradually becomes more restricted within the primary germ layers. PGCs are a notable exception to this paradigm and remain transcriptionally silent until the late gastrula. How the germ-cell lineage retains full potential while somatic cells become fate restricted is a tale of translational repression, selective degradation of somatic maternal determinants, and delayed activation of zygotic transcription.
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Affiliation(s)
- Jing Yang
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Tristan Aguero
- Department of Cell Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA
| | - Mary Lou King
- Department of Cell Biology, University of Miami, Miller School of Medicine, Miami, Florida, USA.
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Nakajima K, Yaoita Y. Development of a new approach for targeted gene editing in primordial germ cells using TALENs in Xenopus. Biol Open 2015; 4:259-66. [PMID: 25661867 PMCID: PMC4359732 DOI: 10.1242/bio.201410926] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 12/09/2014] [Indexed: 11/20/2022] Open
Abstract
A gene of interest can be efficiently modified using transcription activator-like effector nucleases (TALENs) (Christian et al., 2010;Li et al., 2011). However, if a target gene is essential for development, growth and fertility, use of TALENs with high mutagenic activity in F0 frogs could result in developmental disorders or sterility, which would reduce the number of F1 progeny and make F1 phenotypical analysis difficult. We used the 3' untranslated region of DEADSouth gene (DS-3') of Xenopus tropicalis to solve this problem, because the addition of the DS-3' to mRNA is known to induce primordial germ cell (PGC)-specific expression and reduce the stability in somatic cells of mRNA in Xenopus laevis. At first, we inserted the X. tropicalis DS-3' downstream of the EGFP termination codon and confirmed that the EGFP expression was specifically detected in PGCs for three weeks. Therefore, we inserted the DS-3' downstream of the termination codon of the TALEN coding sequence. The tyrosinase gene was selected as the target gene for TALEN because the bi-allelic mutation of this gene is easily discernible by the albino phenotype. When fertilized eggs were microinjected with TALEN mRNAs fused to the DS-3', their sperm and oocytes had a high rate (84-100%) of target-gene modification in contrast to the lower rate (0-45%) of nucleotide alteration observed in somatic cells.
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Affiliation(s)
- Keisuke Nakajima
- Division of Embryology and Genetics, Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashihiroshima 739-8526, Japan
| | - Yoshio Yaoita
- Division of Embryology and Genetics, Institute for Amphibian Biology, Graduate School of Science, Hiroshima University, Higashihiroshima 739-8526, Japan
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