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Konduktorova VV, Luchinskaya NN, Belyavsky AV. Expression of the Germes Germ Plasm Gene in Follicular Cells of X. laevis Oocytes. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422050034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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2
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Evolutionary conservation of maternal RNA localization in fishes and amphibians revealed by TOMO-Seq. Dev Biol 2022; 489:146-160. [PMID: 35752299 DOI: 10.1016/j.ydbio.2022.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 05/18/2022] [Accepted: 06/19/2022] [Indexed: 11/24/2022]
Abstract
Asymmetrical localization of biomolecules inside the egg, results in uneven cell division and establishment of many biological processes, cell types and the body plan. However, our knowledge about evolutionary conservation of localized transcripts is still limited to a few models. Our goal was to compare localization profiles along the animal-vegetal axis of mature eggs from four vertebrate models, two amphibians (Xenopus laevis, Ambystoma mexicanum) and two fishes (Acipenser ruthenus, Danio rerio) using the spatial expression method called TOMO-Seq. We revealed that RNAs of many known important transcripts such as germ layer determinants, germ plasm factors and members of key signalling pathways, are localized in completely different profiles among the models. It was also observed that there was a poor correlation between the vegetally localized transcripts but a relatively good correlation between the animally localized transcripts. These findings indicate that the regulation of embryonic development within the animal kingdom is highly diverse and cannot be deduced based on a single model.
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3
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Hansen CL, Pelegri F. Primordial Germ Cell Specification in Vertebrate Embryos: Phylogenetic Distribution and Conserved Molecular Features of Preformation and Induction. Front Cell Dev Biol 2021; 9:730332. [PMID: 34604230 PMCID: PMC8481613 DOI: 10.3389/fcell.2021.730332] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/25/2021] [Indexed: 11/24/2022] Open
Abstract
The differentiation of primordial germ cells (PGCs) occurs during early embryonic development and is critical for the survival and fitness of sexually reproducing species. Here, we review the two main mechanisms of PGC specification, induction, and preformation, in the context of four model vertebrate species: mouse, axolotl, Xenopus frogs, and zebrafish. We additionally discuss some notable molecular characteristics shared across PGC specification pathways, including the shared expression of products from three conserved germline gene families, DAZ (Deleted in Azoospermia) genes, nanos-related genes, and DEAD-box RNA helicases. Then, we summarize the current state of knowledge of the distribution of germ cell determination systems across kingdom Animalia, with particular attention to vertebrate species, but include several categories of invertebrates - ranging from the "proto-vertebrate" cephalochordates to arthropods, cnidarians, and ctenophores. We also briefly highlight ongoing investigations and potential lines of inquiry that aim to understand the evolutionary relationships between these modes of specification.
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Affiliation(s)
| | - Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States
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4
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Paraiso KD, Cho JS, Yong J, Cho KWY. Early Xenopus gene regulatory programs, chromatin states, and the role of maternal transcription factors. Curr Top Dev Biol 2020; 139:35-60. [PMID: 32450966 DOI: 10.1016/bs.ctdb.2020.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
For decades, the early development of the Xenopus embryo has been an essential model system to study the gene regulatory mechanisms that govern cellular specification. At the top of the hierarchy of gene regulatory networks, maternally deposited transcription factors initiate this process and regulate the expression of zygotic genes that give rise to three distinctive germ layer cell types (ectoderm, mesoderm, and endoderm), and subsequent generation of organ precursors. The onset of germ layer specification is also closely coupled with changes associated with chromatin modifications. This review will examine the timing of maternal transcription factors initiating the zygotic genome activation, the epigenetic landscape of embryonic chromatin, and the network structure that governs the process.
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Affiliation(s)
- Kitt D Paraiso
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States; Center for Complex Biological Systems, University of California, Irvine, CA, United States
| | - Jin S Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States
| | - Junseok Yong
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, United States; Center for Complex Biological Systems, University of California, Irvine, CA, United States.
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5
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Oh D, Houston DW. RNA Localization in the Vertebrate Oocyte: Establishment of Oocyte Polarity and Localized mRNA Assemblages. Results Probl Cell Differ 2019; 63:189-208. [PMID: 28779319 PMCID: PMC6538070 DOI: 10.1007/978-3-319-60855-6_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RNA localization is a fundamental mechanism for controlling cell structure and function. Early development in fish and amphibians requires the localization of specific mRNAs to establish the initial differences in cell fates prior to the onset of zygotic genome activation. RNA localization in these oocytes (e.g., Xenopus and zebrafish) requires that animal-vegetal polarity be established early in oogenesis, mediated by formation of the Balbiani body/mitochondrial cloud. This structure serves as a platform for assembly and transport of germline determinants to the future vegetal pole and also sets up the machinery for the localization of non-germline transcripts later in oogenesis. Understanding these polarization and localization mechanisms is critical for understanding the basis for early embryonic development in these organisms and also for understanding the role of RNA compartmentalization in animal gametogenesis. Here we outline recent advances in elucidating the molecular basis for the establishment of oocyte polarity at the level of Balbiani body assembly as well as the formation of RNP assemblies for early and late pathway mRNA localization in the oocyte.
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Affiliation(s)
- Denise Oh
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA, 52242, USA
| | - Douglas W Houston
- Department of Biology, The University of Iowa, 257 BB, Iowa City, IA, 52242, USA.
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6
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Germ plasm provides clues on meiosis: the concerted action of germ plasm granules and mitochondria in gametogenesis of the clam Ruditapes philippinarum. ZYGOTE 2018; 27:25-35. [PMID: 30523771 DOI: 10.1017/s0967199418000588] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryGerm plasm-related structures (GPRS) are known to accompany meiotic cell differentiation but their dynamics are still poorly understood. In this study, we analyzed the ultrastructural mechanisms of GPRS transformation during oogenesis and spermatogenesis of the bivalve mollusc Ruditapes philippinarum (Manila clam), exploring patterns of GPRS activity occurring at meiosis onset, sex-specific difference/similarity of such patterns, and the involvement of mitochondria during GPRS-assigned events. In the two sexes, the zygotene-pachytene stage of meiosis is anticipated by three shared steps. First, the dispersion of germ plasm granules containing the germ line determinant VASA occurs. Second, the VASA protein deriving from germ plasm granules enters neighbouring mitochondria and appears to induce mitochondrial matter release, as supported by cytochrome B localization outside the mitochondria. Third, intranuclear VASA entrance occurs and the protein appears involved in chromatin reorganization, as supported by VASA localization in synaptonemal complexes. In spermatogenesis, these three steps are sufficient for the normal course of meiosis. In oogenesis, these are followed by the action of 'germ plasm granule formation complex', a novel type of structure that appears alternative to the Balbiani body. The possibility of germ plasm involvement in reproductive technologies is also suggested.
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7
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Sindelka R, Abaffy P, Qu Y, Tomankova S, Sidova M, Naraine R, Kolar M, Peuchen E, Sun L, Dovichi N, Kubista M. Asymmetric distribution of biomolecules of maternal origin in the Xenopus laevis egg and their impact on the developmental plan. Sci Rep 2018; 8:8315. [PMID: 29844480 PMCID: PMC5974320 DOI: 10.1038/s41598-018-26592-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/08/2018] [Indexed: 12/24/2022] Open
Abstract
Asymmetric cell division is a ubiquitous feature during the development of higher organisms. Asymmetry is achieved by differential localization or activities of biological molecules such as proteins, and coding and non-coding RNAs. Here, we present subcellular transcriptomic and proteomic analyses along the animal-vegetal axis of Xenopus laevis eggs. More than 98% of the maternal mRNAs could be categorized into four localization profile groups: animal, vegetal, extremely vegetal, and a newly described group of mRNAs that we call extremely animal, which are mRNAs enriched in the animal cortex region. 3′UTRs of localized mRNAs were analyzed for localization motifs. Several putative motifs were discovered for vegetal and extremely vegetal mRNAs, while no distinct conserved motifs for the extremely animal mRNAs were identified, suggesting different localization mechanisms. Asymmetric profiles were also found for proteins, with correlation to those of corresponding mRNAs. Based on unexpected observation of the profiles of the homoeologous genes exd2 we propose a possible mechanism of genetic evolution.
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Affiliation(s)
- Radek Sindelka
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic.
| | - Pavel Abaffy
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic
| | - Yanyan Qu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Silvie Tomankova
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic
| | - Monika Sidova
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic
| | - Ravindra Naraine
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic
| | - Michal Kolar
- Institute of Molecular Genetics, Videnska 1083, 142 20, Prague 4, Czech Republic
| | - Elizabeth Peuchen
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Liangliang Sun
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA.,Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Norman Dovichi
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Mikael Kubista
- Institute of Biotechnology of the Czech Academy of Sciences - BIOCEV, Prumyslova 595, Vestec, 252 50, Czech Republic.,TATAA Biocenter, Odinsgatan 28, Göteborg, 411 03, Sweden
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8
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Pocherniaieva K, Sidova M, Havelka M, Saito T, Psenicka M, Sindelka R, Kaspar V. Comparison of oocyte mRNA localization patterns in sterlet Acipenser ruthenus and African clawed frog Xenopus laevis. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2018; 330:181-187. [PMID: 29682883 DOI: 10.1002/jez.b.22802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 01/13/2018] [Accepted: 03/13/2018] [Indexed: 11/09/2022]
Abstract
In oocytes, RNA localization has critical implications, as assembly of proteins in particular subcellular domains is crucial to embryo development. The distribution of mRNA molecules can identify and characterize localized transcripts. The goal of this study was to clarify the origin of primordial germ cells in the oocyte body plan and to reveal the generation of cell lineages by localized RNAs. The distribution of 12 selected mRNAs in sterlet Acipenser ruthenus oocytes was investigated by qPCR tomography and compared with known patterns of mRNA localization in Xenopus laevis. We investigated the distribution of two gene clusters in the ooplasm along the animal-vegetal axis of the sturgeon oocyte, both of which showed clearly defined intracellular gradient pattern remarkably similar to their distribution in the frog oocyte. We elucidated the localization of sturgeon egg germplasm markers belonging to the vegetal group of mRNAs. The mRNAs coding otx1, wnt11, and veg1 found to be localized in the sturgeon animal hemisphere are, in contrast, distributed in the vegetal hemisphere in amphibian. Actinopterygii and Sarcopterygii, two major lineages of osteichthyan vertebrates, split about 476 Ma (Blair & Hedges, ), albeit basal lineages share conserved biological features. Acipenseriformes is one the most basal living lineages of Actinopterygii, having evolved about 200 Ma (Bemis, Birstein, & Waldman, ), contemporaneous with modern amphibians (Roelants et al., ).
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Affiliation(s)
- Kseniia Pocherniaieva
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic
| | - Monika Sidova
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Milos Havelka
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic.,Faculty and Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Taiju Saito
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic
| | - Martin Psenicka
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic
| | - Radek Sindelka
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Vojtech Kaspar
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Vodňany, Czech Republic
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9
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Silva J, Aivio S, Knobel PA, Bailey LJ, Casali A, Vinaixa M, Garcia-Cao I, Coyaud É, Jourdain AA, Pérez-Ferreros P, Rojas AM, Antolin-Fontes A, Samino-Gené S, Raught B, González-Reyes A, Ribas de Pouplana L, Doherty AJ, Yanes O, Stracker TH. EXD2 governs germ stem cell homeostasis and lifespan by promoting mitoribosome integrity and translation. Nat Cell Biol 2018; 20:162-174. [PMID: 29335528 DOI: 10.1038/s41556-017-0016-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 11/27/2017] [Indexed: 02/08/2023]
Abstract
Mitochondria are subcellular organelles that are critical for meeting the bioenergetic and biosynthetic needs of the cell. Mitochondrial function relies on genes and RNA species encoded both in the nucleus and mitochondria, and on their coordinated translation, import and respiratory complex assembly. Here, we characterize EXD2 (exonuclease 3'-5' domain-containing 2), a nuclear-encoded gene, and show that it is targeted to the mitochondria and prevents the aberrant association of messenger RNAs with the mitochondrial ribosome. Loss of EXD2 results in defective mitochondrial translation, impaired respiration, reduced ATP production, increased reactive oxygen species and widespread metabolic abnormalities. Depletion of the Drosophila melanogaster EXD2 orthologue (CG6744) causes developmental delays and premature female germline stem cell attrition, reduced fecundity and a dramatic extension of lifespan that is reversed with an antioxidant diet. Our results define a conserved role for EXD2 in mitochondrial translation that influences development and ageing.
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Affiliation(s)
- Joana Silva
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Suvi Aivio
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA
| | - Philip A Knobel
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Department for Radiation Oncology, University Hospital Zurich, Zurich, Switzerland
| | - Laura J Bailey
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Andreu Casali
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Maria Vinaixa
- Metabolomics Platform, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Spain.,Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
| | - Isabel Garcia-Cao
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Étienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Alexis A Jourdain
- Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Pablo Pérez-Ferreros
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,EMBL Australia, University of New South Wales, Lowy Cancer Research Center, Single Molecule Science Node, Sydney and Arc Center of Excellence in Advance Molecular Imaging, Sydney, New South Wales, Australia
| | - Ana M Rojas
- Computational Biology and Bioinformatics Group, Institute of Biomedicine of Seville (IBIS/CSIC/US/JA), Campus Hospital Universitario Virgen del Rocio, Seville, Spain
| | - Albert Antolin-Fontes
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Sara Samino-Gené
- Metabolomics Platform, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Spain.,Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Acaimo González-Reyes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC/JA, Seville, Spain
| | - Lluís Ribas de Pouplana
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Oscar Yanes
- Metabolomics Platform, Department of Electronic Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Spain.,Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
| | - Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
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10
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Bilinski SM, Kloc M, Tworzydlo W. Selection of mitochondria in female germline cells: is Balbiani body implicated in this process? J Assist Reprod Genet 2017; 34:1405-1412. [PMID: 28755153 PMCID: PMC5699987 DOI: 10.1007/s10815-017-1006-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/21/2017] [Indexed: 11/13/2022] Open
Abstract
Early oocytes of nearly all animal species contain a transient organelle assemblage termed the Balbiani body. Structure and composition of this assemblage may vary even between closely related species. Despite this variability, the Balbiani body always comprises of numerous tightly clustered mitochondria and accumulations of nuage material. It has been suggested that the Balbiani body is an evolutionarily ancestral structure, which plays a role in various processes such as the localization of organelles and macromolecules to the germ plasm, lipidogenesis, as well as the selection/elimination of dysfunctional mitochondria from female germline cells. We suggest that the selection/elimination of mitochondria is a primary and evolutionarily ancestral function of Balbiani body, and that the other functions are secondary, evolutionarily derived additions. We propose a simple model explaining the role of the Balbiani body in the selection of mitochondria, i.e., in the mitochondrial DNA (mtDNA) bottleneck phenomenon.
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Affiliation(s)
- Szczepan M Bilinski
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland.
| | - Malgorzata Kloc
- The Houston Methodist Research Institute and The Houston Methodist Hospital, 6670 Bertner Ave, Houston, TX, 77030, USA
| | - Waclaw Tworzydlo
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Krakow, Poland
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11
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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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12
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Toombs JA, Sytnikova YA, Chirn GW, Ang I, Lau NC, Blower MD. Xenopus Piwi proteins interact with a broad proportion of the oocyte transcriptome. RNA (NEW YORK, N.Y.) 2017; 23:504-520. [PMID: 28031481 PMCID: PMC5340914 DOI: 10.1261/rna.058859.116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/21/2016] [Indexed: 06/06/2023]
Abstract
Piwi proteins utilize small RNAs (piRNAs) to recognize target transcripts such as transposable elements (TE). However, extensive piRNA sequence diversity also suggests that Piwi/piRNA complexes interact with many transcripts beyond TEs. To determine Piwi target RNAs, we used ribonucleoprotein-immunoprecipitation (RIP) and cross-linking and immunoprecipitation (CLIP) to identify thousands of transcripts associated with the Piwi proteins XIWI and XILI (Piwi-protein-associated transcripts, PATs) from early stage oocytes of X. laevis and X. tropicalis Most PATs associate with both XIWI and XILI and include transcripts of developmentally important proteins in oogenesis and embryogenesis. Only a minor fraction of PATs in both frog species displayed near perfect matches to piRNAs. Since predicting imperfect pairing between all piRNAs and target RNAs remains intractable, we instead determined that PAT read counts correlate well with the lengths and expression levels of transcripts, features that have also been observed for oocyte mRNAs associated with Drosophila Piwi proteins. We used an in vitro assay with exogenous RNA to confirm that XIWI associates with RNAs in a length- and concentration-dependent manner. In this assay, noncoding transcripts with many perfectly matched antisense piRNAs were unstable, whereas coding transcripts with matching piRNAs were stable, consistent with emerging evidence that Piwi proteins both promote the turnover of TEs and other RNAs, and may also regulate mRNA localization and translation. Our study suggests that Piwi proteins play multiple roles in germ cells and establishes a tractable vertebrate system to study the role of Piwi proteins in transcript regulation.
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Affiliation(s)
- James A Toombs
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Yuliya A Sytnikova
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Gung-Wei Chirn
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Ignatius Ang
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Nelson C Lau
- Department of Biology and Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts 02454, USA
| | - Michael D Blower
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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13
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Sindelka R, Sidova M, Abaffy P, Kubista M. Asymmetric Localization and Distribution of Factors Determining Cell Fate During Early Development of Xenopus laevis. Results Probl Cell Differ 2017; 61:229-241. [PMID: 28409307 DOI: 10.1007/978-3-319-53150-2_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Asymmetric division is a property of eukaryotic cells that is fundamental to the formation of higher life forms. Despite its importance, the mechanism behind it remains elusive. Asymmetry in the cell is induced by polarization of cell fate determinants that become unevenly distributed among progeny cells. So far dozens of determinants have been identified. Xenopus laevis is an ideal system to study asymmetric cell division during early development, because of the huge size of its oocytes and early-stage blastomeres. Here, we present the current knowledge about localization and distribution of cell fate determinants along the three body axes: animal-vegetal, dorsal-ventral, and left-right. Uneven distribution of cell fate determinants during early development specifies the formation of the embryonic body plan.
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Affiliation(s)
- Radek Sindelka
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic-Biocev, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Monika Sidova
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic-Biocev, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Pavel Abaffy
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic-Biocev, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Mikael Kubista
- Laboratory of Gene Expression, Institute of Biotechnology, Academy of Sciences of the Czech Republic-Biocev, Prumyslova 595, 252 50, Vestec, Czech Republic.
- TATAA Biocenter AB, Odinsgatan 28, 411 03, Göteborg, Sweden.
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14
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Mechanisms of Vertebrate Germ Cell Determination. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 953:383-440. [PMID: 27975276 DOI: 10.1007/978-3-319-46095-6_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Two unique characteristics of the germ line are the ability to persist from generation to generation and to retain full developmental potential while differentiating into gametes. How the germ line is specified that allows it to retain these characteristics within the context of a developing embryo remains unknown and is one focus of current research. Germ cell specification proceeds through one of two basic mechanisms: cell autonomous or inductive. Here, we discuss how germ plasm driven germ cell specification (cell autonomous) occurs in both zebrafish and the frog Xenopus. We describe the segregation of germ cells during embryonic development of solitary and colonial ascidians to provide an evolutionary context to both mechanisms. We conclude with a discussion of the inductive mechanism as exemplified by both the mouse and axolotl model systems. Regardless of mechanism, several general themes can be recognized including the essential role of repression and posttranscriptional regulation of gene expression.
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15
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King ML. Maternal messages to live by: a personal historical perspective. Genesis 2017; 55:10.1002/dvg.23007. [PMID: 28095642 PMCID: PMC5276792 DOI: 10.1002/dvg.23007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 11/22/2016] [Accepted: 11/24/2016] [Indexed: 12/17/2022]
Abstract
In the 1980s, the study of localized maternal mRNAs was just emerging as a new research area. Classic embryological studies had linked the inheritance of cytoplasmic domains with specific cell lineages, but the underlying molecular nature of these putative determinants remained a mystery. The model system Xenopus would play a pivotal role in the progress of this new field. In fact, the first localized maternal mRNA to be identified and cloned from any organism was Xenopus vg1, a TGF-beta family member. This seminal finding opened the door to many subsequent studies focused on how RNAs are localized and what functions they had in development. As the field moves into the future, Xenopus remains the system of choice for studies identifying RNA/protein transport particles and maternal RNAs through RNA-sequencing.
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Affiliation(s)
- 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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16
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Localization in Oogenesis of Maternal Regulators of Embryonic Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 953:173-207. [DOI: 10.1007/978-3-319-46095-6_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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17
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Lombard-Banek C, Moody SA, Nemes P. High-Sensitivity Mass Spectrometry for Probing Gene Translation in Single Embryonic Cells in the Early Frog ( Xenopus) Embryo. Front Cell Dev Biol 2016; 4:100. [PMID: 27761436 PMCID: PMC5050209 DOI: 10.3389/fcell.2016.00100] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/29/2016] [Indexed: 01/01/2023] Open
Abstract
Direct measurement of protein expression with single-cell resolution promises to deepen the understanding of the basic molecular processes during normal and impaired development. High-resolution mass spectrometry provides detailed coverage of the proteomic composition of large numbers of cells. Here we discuss recent mass spectrometry developments based on single-cell capillary electrophoresis that extend discovery proteomics to sufficient sensitivity to enable the measurement of proteins in single cells. The single-cell mass spectrometry system is used to detect a large number of proteins in single embryonic cells in the 16-cell embryo of the South African clawed frog (Xenopus laevis) that give rise to distinct tissue types. Single-cell measurements of protein expression provide complementary information on gene transcription during early development of the vertebrate embryo, raising a potential to understand how differential gene expression coordinates normal cell heterogeneity during development.
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Affiliation(s)
| | - Sally A Moody
- Department of Anatomy and Regenerative Biology, The George Washington University Washington, DC, USA
| | - Peter Nemes
- Department of Chemistry, The George Washington University Washington, DC, USA
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18
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Onjiko RM, Morris SE, Moody SA, Nemes P. Single-cell mass spectrometry with multi-solvent extraction identifies metabolic differences between left and right blastomeres in the 8-cell frog (Xenopus) embryo. Analyst 2016; 141:3648-56. [PMID: 27004603 PMCID: PMC4899105 DOI: 10.1039/c6an00200e] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Single-cell metabolic mass spectrometry enables the discovery (untargeted) analysis of small molecules in individual cells. Using single-cell capillary electrophoresis high-resolution mass spectrometry (CE-HRMS), we recently uncovered small-molecule differences between embryonic cells located along the animal-vegetal and dorsal-ventral axes of the 16-cell frog (Xenopus laevis) embryo, raising the question whether metabolic cell heterogeneity also exists along the left-right body axis. To address this question, we here advance single-cell CE-HRMS for identifying and quantifying metabolites in higher analytical sensitivity, and then use the methodology to compare metabolite production between left and right cells. Our strategy utilizes multiple solvents with complementary physicochemical properties to extract small molecules from single cells and improve electrophoretic separation, increasing metabolite ion signals for quantification and tandem HRMS. As a result, we were able to identify 55 different small molecules in D1 cells that were isolated from 8-cell embryos. To quantify metabolite production between left and right cells, we analyzed n = 24 different D1 cells in technical duplicate-triplicate measurements. Statistical and multivariate analysis based on 80 of the most repeatedly quantified compounds revealed 10 distinct metabolites that were significantly differentially accumulated in the left or right cells (p < 0.05 and fold change ≥1.5). These metabolites were enriched in the arginine-proline metabolic pathway in the right, but not the left D1 cells. Besides providing analytical benefits for single-cell HRMS, this work provides new metabolic data on the establishment of normal body asymmetry in the early developing embryo.
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Affiliation(s)
- Rosemary M Onjiko
- Department of Chemistry, The George Washington University, Washington, DC 20052, USA.
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19
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Gaur S, Mandelbaum M, Herold M, Majumdar HD, Neilson KM, Maynard TM, Mood K, Daar IO, Moody SA. Neural transcription factors bias cleavage stage blastomeres to give rise to neural ectoderm. Genesis 2016; 54:334-49. [PMID: 27092474 PMCID: PMC4912902 DOI: 10.1002/dvg.22943] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 01/23/2023]
Abstract
The decision by embryonic ectoderm to give rise to epidermal versus neural derivatives is the result of signaling events during blastula and gastrula stages. However, there also is evidence in Xenopus that cleavage stage blastomeres contain maternally derived molecules that bias them toward a neural fate. We used a blastomere explant culture assay to test whether maternally deposited transcription factors bias 16-cell blastomere precursors of epidermal or neural ectoderm to express early zygotic neural genes in the absence of gastrulation interactions or exogenously supplied signaling factors. We found that Foxd4l1, Zic2, Gmnn, and Sox11 each induced explants made from ventral, epidermis-producing blastomeres to express early neural genes, and that at least some of the Foxd4l1 and Zic2 activities are required at cleavage stages. Similarly, providing extra Foxd4l1 or Zic2 to explants made from dorsal, neural plate-producing blastomeres significantly increased the expression of early neural genes, whereas knocking down either significantly reduced them. These results show that maternally delivered transcription factors bias cleavage stage blastomeres to a neural fate. We demonstrate that mouse and human homologs of Foxd4l1 have similar functional domains compared to the frog protein, as well as conserved transcriptional activities when expressed in Xenopus embryos and blastomere explants. genesis 54:334-349, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Shailly Gaur
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Max Mandelbaum
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Mona Herold
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Himani Datta Majumdar
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Karen M. Neilson
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | | | - Kathy Mood
- Laboratory of Cell and Developmental Signaling, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Ira O. Daar
- Laboratory of Cell and Developmental Signaling, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
- George Washington University Institute for Neuroscience
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20
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Reid CD, Karra K, Chang J, Piskol R, Li Q, Li JB, Cherry JM, Baker JC. XenMine: A genomic interaction tool for the Xenopus community. Dev Biol 2016; 426:155-164. [PMID: 27157655 DOI: 10.1016/j.ydbio.2016.02.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/06/2016] [Accepted: 02/26/2016] [Indexed: 11/17/2022]
Abstract
The Xenopus community has embraced recent advances in sequencing technology, resulting in the accumulation of numerous RNA-Seq and ChIP-Seq datasets. However, easily accessing and comparing datasets generated by multiple laboratories is challenging. Thus, we have created a central space to view, search and analyze data, providing essential information on gene expression changes and regulatory elements present in the genome. XenMine (www.xenmine.org) is a user-friendly website containing published genomic datasets from both Xenopus tropicalis and Xenopus laevis. We have established an analysis pipeline where all published datasets are uniformly processed with the latest genome releases. Information from these datasets can be extracted and compared using an array of pre-built or custom templates. With these search tools, users can easily extract sequences for all putative regulatory domains surrounding a gene of interest, identify the expression values of a gene of interest over developmental time, and analyze lists of genes for gene ontology terms and publications. Additionally, XenMine hosts an in-house genome browser that allows users to visualize all available ChIP-Seq data, extract specifically marked sequences, and aid in identifying important regulatory elements within the genome. Altogether, XenMine is an excellent tool for visualizing, accessing and querying analyzed datasets rapidly and efficiently.
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Affiliation(s)
- Christine D Reid
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Kalpana Karra
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Jessica Chang
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Robert Piskol
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Qin Li
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Jin Billy Li
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - J Michael Cherry
- Department of Genetics, Stanford University, Stanford CA 94305, USA
| | - Julie C Baker
- Department of Genetics, Stanford University, Stanford CA 94305, USA.
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21
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De Domenico E, Owens NDL, Grant IM, Gomes-Faria R, Gilchrist MJ. Molecular asymmetry in the 8-cell stage Xenopus tropicalis embryo described by single blastomere transcript sequencing. Dev Biol 2015; 408:252-68. [PMID: 26100918 PMCID: PMC4684228 DOI: 10.1016/j.ydbio.2015.06.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 12/17/2022]
Abstract
Correct development of the vertebrate body plan requires the early definition of two asymmetric, perpendicular axes. The first axis is established during oocyte maturation, and the second is established by symmetry breaking shortly after fertilization. The physical processes generating the second asymmetric, or dorsal-ventral, axis are well understood, but the specific molecular determinants, presumed to be maternal gene products, are poorly characterized. Whilst enrichment of maternal mRNAs at the animal and vegetal poles in both the oocyte and the early embryo has been studied, little is known about the distribution of maternal mRNAs along either the dorsal-ventral or left-right axes during the early cleavage stages. Here we report an unbiased analysis of the distribution of maternal mRNA on all axes of the Xenopus tropicalis 8-cell stage embryo, based on sequencing of single blastomeres whose positions within the embryo are known. Analysis of pooled data from complete sets of blastomeres from four embryos has identified 908 mRNAs enriched in either the animal or vegetal blastomeres, of which 793 are not previously reported as enriched. In contrast, we find no evidence for asymmetric distribution along either the dorsal-ventral or left-right axes. We confirm that animal pole enrichment is on average distinctly lower than vegetal pole enrichment, and that considerable variation is found between reported enrichment levels in different studies. We use publicly available data to show that there is a significant association between genes with human disease annotation and enrichment at the animal pole. Mutations in the human ortholog of the most animally enriched novel gene, Slc35d1, are causative for Schneckenbecken dysplasia, and we show that a similar phenotype is produced by depletion of the orthologous protein in Xenopus embryos.
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Affiliation(s)
- Elena De Domenico
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Nick D L Owens
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Ian M Grant
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Rosa Gomes-Faria
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Michael J Gilchrist
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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22
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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: 12] [Impact Index Per Article: 1.3] [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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23
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Intracellular microRNA profiles form in the Xenopus laevis oocyte that may contribute to asymmetric cell division. Sci Rep 2015; 5:11157. [PMID: 26059897 PMCID: PMC4461913 DOI: 10.1038/srep11157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 05/18/2015] [Indexed: 12/17/2022] Open
Abstract
Asymmetric distribution of fate determinants within cells is an essential biological strategy to prepare them for asymmetric division. In this work we measure the intracellular distribution of 12 maternal microRNAs (miRNA) along the animal-vegetal axis of the Xenopus laevis oocyte using qPCR tomography. We find the miRNAs have distinct intracellular profiles that resemble two out of the three profiles we previously observed for mRNAs. Our results suggest that miRNAs in addition to proteins and mRNAs may have asymmetric distribution within the oocyte and may contribute to asymmetric cell division as cell fate determinants.
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24
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Kloc M, Jedrzejowska I, Tworzydlo W, Bilinski SM. Balbiani body, nuage and sponge bodies--term plasm pathway players. ARTHROPOD STRUCTURE & DEVELOPMENT 2014; 43:341-8. [PMID: 24398038 DOI: 10.1016/j.asd.2013.12.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/28/2013] [Accepted: 12/18/2013] [Indexed: 05/14/2023]
Abstract
In many animal species, germ cells are specified by maternally provided, often asymmetrically localized germ cell determinant, termed the germ plasm. It has been shown that in model organisms such as Xenopus laevis, Danio rerio and Drosophila melanogaster germ plasm components (various proteins, mRNAs and mitochondria) are delivered to the proper position within the egg cell by germline specific organelles, i.e. Balbiani bodies, nuage accumulations and/or sponge bodies. In the present article, we review the current knowledge on morphology, molecular composition and functioning of these organelles in main lineages of arthropods and different ovary types on the backdrop of data derived from the studies of the model vertebrate species.
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Affiliation(s)
- Malgorzata Kloc
- The Houston Methodist Hospital, The Houston Methodist Hospital Research Institute, Houston, TX, USA
| | - Izabela Jedrzejowska
- Department of Animal Developmental Biology, Institute of Experimental Biology, University of Wroclaw, Wroclaw, Poland
| | - Waclaw Tworzydlo
- Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology, Jagiellonian University, Krakow, Poland
| | - Szczepan M Bilinski
- Department of Developmental Biology and Morphology of Invertebrates, Institute of Zoology, Jagiellonian University, Krakow, Poland.
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25
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In mouse oocytes the mitochondrion-originated germinal body-like structures accumulate mouse Vasa homologue (MVH) protein. ZYGOTE 2014; 23:501-6. [DOI: 10.1017/s0967199414000124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SummaryMouse Vasa homologue (MVH) antibodies were applied to mouse Graafian oocytes to clarify if mitochondrion-originated germinal body-like structures, described previously by conventional electron microscopy, were associated with the germ plasm. It was found that both the mitochondrion-like structures with cristae and the germinal body-like structures that lacked any signs of cristae were labelled specifically by the anti-MVH antibody. Moreover, some granules were MVH-positive ultrastructural hybrids of the mitochondria and germinal body-like structures, the presence of which clearly supported the idea of a mitochondrial origin for the germinal body-like structures. This finding is the first evidence that mitochondrion-originated germinal body-like granules represent mouse germ plasm.
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26
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Single blastomere expression profiling of Xenopus laevis embryos of 8 to 32-cells reveals developmental asymmetry. Sci Rep 2014; 3:2278. [PMID: 23880666 PMCID: PMC3721081 DOI: 10.1038/srep02278] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/05/2013] [Indexed: 12/24/2022] Open
Abstract
We have measured the expression of 41 maternal mRNAs in individual blastomeres collected from the 8 to 32-cell Xenopus laevis embryos to determine when and how asymmetry in the body plan is introduced. We demonstrate that the asymmetry along the animal-vegetal axis in the oocyte is transferred to the daughter cells during early cell divisions. All studied mRNAs are distributed evenly among the set of animal as well as vegetal blastomeres. We find no asymmetry in mRNA levels that might be ascribed to the dorso-ventral specification or the left-right axis formation. We hypothesize that while the animal-vegetal asymmetry is a consequence of mRNA gradients, the dorso-ventral and left-right axes specifications are induced by asymmetric distribution of other biomolecules, probably proteins.
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27
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Grant PA, Yan B, Johnson MA, Johnson DLE, Moody SA. Novel animal pole-enriched maternal mRNAs are preferentially expressed in neural ectoderm. Dev Dyn 2013; 243:478-96. [PMID: 24155242 DOI: 10.1002/dvdy.24082] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 08/27/2013] [Accepted: 09/04/2013] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Many animals utilize maternal mRNAs to pre-pattern the embryo before the onset of zygotic transcription. In Xenopus laevis, vegetal factors specify the germ line, endoderm, and dorsal axis, but there are few studies demonstrating roles for animal-enriched maternal mRNAs. Therefore, we carried out a microarray analysis to identify novel maternal transcripts enriched in 8-cell-stage animal blastomeres. RESULTS We identified 39 mRNAs isolated from 8-cell animal blastomeres that are >4-fold enriched compared to vegetal pole mRNAs. We characterized 14 of these that are of unknown function. We validated the microarray results for 8/14 genes by qRT-PCR and for 14/14 genes by in situ hybridization assays. Because no developmental functions are reported yet, we provide the expression patterns for each of the 14 genes. Each is expressed in the animal hemisphere of unfertilized eggs, 8-cell animal blastomeres, and diffusely in blastula animal cap ectoderm, gastrula ectoderm and neural ectoderm, neural crest (and derivatives) and cranial placodes (and derivatives). They have varying later expression in some mesodermal and endodermal tissues in tail bud through larval stages. CONCLUSIONS Novel animal-enriched maternal mRNAs are preferentially expressed in ectodermal derivatives, particularly neural ectoderm. However, they are later expressed in derivatives of other germ layers.
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Affiliation(s)
- Paaqua A Grant
- Department of Biological Sciences, The George Washington University, Columbian College of Arts and Sciences, Washington, DC
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28
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Yamaguchi T, Kataoka K, Watanabe K, Orii H. Restriction of the Xenopus DEADSouth mRNA to the primordial germ cells is ensured by multiple mechanisms. Mech Dev 2013; 131:15-23. [PMID: 24291337 DOI: 10.1016/j.mod.2013.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 10/26/2013] [Accepted: 11/17/2013] [Indexed: 02/04/2023]
Abstract
DEADSouth mRNA encoding the RNA helicase DDX25 is a component of the germ plasm in Xenopus laevis. We investigated the mechanisms underlying its specific mRNA expression in primordial germ cells (PGCs). Based on our previous findings of several microRNA miR-427 recognition elements (MREs) in the 3' untranslated region of the mRNA, we first examined whether DEADSouth mRNA was degraded by miR-427 targeting in somatic cells. Injection of antisense miR-427 oligomer and reporter mRNA for mutated MREs revealed that DEADSouth mRNA was potentially degraded in somatic cells via miR-427 targeting, but not in PGCs after the mid-blastula transition (MBT). The expression level of miR-427 was very low in PGCs, which probably resulted in the lack of miR-427-mediated degradation. In addition, the DEADSouth gene was expressed zygotically after MBT. Thus, the predominant expression of DEADSouth mRNA in the PGCs is ensured by multiple mechanisms including zygotic expression and prohibition from miR-427-mediated degradation.
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Affiliation(s)
- Takeshi Yamaguchi
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan
| | - Kensuke Kataoka
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan
| | - Kenji Watanabe
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan
| | - Hidefumi Orii
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun, Hyogo 678-1297, Japan.
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29
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Hulstrand AM, Houston DW. Regulation of neurogenesis by Fgf8a requires Cdc42 signaling and a novel Cdc42 effector protein. Dev Biol 2013; 382:385-99. [PMID: 23994638 DOI: 10.1016/j.ydbio.2013.08.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 08/11/2013] [Accepted: 08/21/2013] [Indexed: 11/16/2022]
Abstract
Fibroblast growth factor (FGF) signaling is required for numerous aspects of neural development, including neural induction, CNS patterning and neurogenesis. The ability of FGFs to activate Ras/MAPK signaling is thought to be critical for these functions. However, it is unlikely that MAPK signaling can fully explain the diversity of responses to FGFs. We have characterized a Cdc42-dependent signaling pathway operating downstream of the Fgf8a splice isoform. We show that a Cdc42 effector 4-like protein (Cdc42ep4-l or Cep4l) has robust neuronal-inducing activity in Xenopus embryos. Furthermore, we find that Cep4l and Cdc42 itself are necessary and sufficient for sensory neurogenesis in vivo. Furthermore, both proteins are involved in Fgf8a-induced neuronal induction, and Cdc42/Cep4l association is promoted specifically by the Fgf8a isoform of Fgf8, but not by Fgf8b, which lacks neuronal inducing activity. Overall, these data suggest a novel role for Cdc42 in an Fgf8a-specific signaling pathway essential for vertebrate neuronal development.
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Affiliation(s)
- Alissa M Hulstrand
- Department of Biology and Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
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30
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Cattell MV, Garnett AT, Klymkowsky MW, Medeiros DM. A maternally established SoxB1/SoxF axis is a conserved feature of chordate germ layer patterning. Evol Dev 2013; 14:104-15. [PMID: 23016978 DOI: 10.1111/j.1525-142x.2011.00525.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Despite deep evolutionary roots in the metazoa, the gene regulatory network driving germ layer specification is surprisingly labile both between and within phyla. In Xenopus laevis, SoxB1- and SoxF-type transcription factors are intimately involved in germ-layer specification, in part through their regulation of Nodal signaling. However, it is unclear if X. laevis is representative of the ancestral vertebrate condition, as the precise roles of SoxF and SoxB1 in germ-layer specification vary among vertebrates, and there is no evidence that SoxF mediates germ-layer specification in any invertebrate. To better understand the evolution of germ-layer specification in the vertebrate lineage, we analyzed the expression of soxB1 and soxF genes in embryos and larvae of the basal vertebrate lamprey, and the basal chordate amphioxus. We find that both species maternally deposit soxB1 mRNA in the animal pole, soxF mRNA in the vegetal hemisphere, and zygotically express soxB1 and soxF throughout nascent ectoderm and mesendoderm, respectively. We also find that soxF is excluded from the vegetalmost blastomeres in lamprey and that, in contrast to vertebrates, amphioxus does not express soxF in the oral epithelium. In the context of recent work, our results suggest that a maternally established animal/vegetal Sox axis is a deeply conserved feature of chordate development that predates the role of Nodal in vertebrate germ-layer specification. Furthermore, exclusion of this axis from the vegetal pole in lamprey is consistent with the presence of an extraembryonic yolk mass, as has been previously proposed. Finally, conserved expression of SoxF in the forming mouth across the vertebrates, but not in amphioxus, lends support to the idea that the larval amphioxus mouth is nonhomologous to the vertebrate mouth.
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Affiliation(s)
- Maria V Cattell
- Ecology and Evolutionary Biology, University of Colorado-Boulder, CO 80309-0334, USA
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Lai F, King ML. Repressive translational control in germ cells. Mol Reprod Dev 2013; 80:665-76. [DOI: 10.1002/mrd.22161] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 02/02/2013] [Indexed: 02/04/2023]
Affiliation(s)
- Fangfang Lai
- Department of Cell Biology; University of Miami Miller School of Medicine; Miami; Florida
| | - Mary Lou King
- Department of Cell Biology; University of Miami Miller School of Medicine; Miami; Florida
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Regulation of cell polarity and RNA localization in vertebrate oocytes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:127-85. [PMID: 24016525 DOI: 10.1016/b978-0-12-407694-5.00004-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
It has long been appreciated that the inheritance of maternal cytoplasmic determinants from different regions of the egg can lead to differential specification of blastomeres during cleavage. Localized RNAs are important determinants of cell fate in eggs and embryos but are also recognized as fundamental regulators of cell structure and function. This chapter summarizes recent molecular and genetic experiments regarding: (1) mechanisms that regulate polarity during different stages of vertebrate oogenesis, (2) pathways that localize presumptive protein and RNA determinants within the polarized oocyte and egg, and (3) how these determinants act in the embryo to determine the ultimate cell fates. Emphasis is placed on studies done in Xenopus, where extensive work has been done in these areas, and comparisons are drawn with fish and mammals. The prospects for future work using in vivo genome manipulation and other postgenomic approaches are also discussed.
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Mason PA, Cox LS. The role of DNA exonucleases in protecting genome stability and their impact on ageing. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1317-1340. [PMID: 21948156 PMCID: PMC3528374 DOI: 10.1007/s11357-011-9306-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/19/2011] [Indexed: 05/30/2023]
Abstract
Exonucleases are key enzymes involved in many aspects of cellular metabolism and maintenance and are essential to genome stability, acting to cleave DNA from free ends. Exonucleases can act as proof-readers during DNA polymerisation in DNA replication, to remove unusual DNA structures that arise from problems with DNA replication fork progression, and they can be directly involved in repairing damaged DNA. Several exonucleases have been recently discovered, with potentially critical roles in genome stability and ageing. Here we discuss how both intrinsic and extrinsic exonuclease activities contribute to the fidelity of DNA polymerases in DNA replication. The action of exonucleases in processing DNA intermediates during normal and aberrant DNA replication is then assessed, as is the importance of exonucleases in repair of double-strand breaks and interstrand crosslinks. Finally we examine how exonucleases are involved in maintenance of mitochondrial genome stability. Throughout the review, we assess how nuclease mutation or loss predisposes to a range of clinical diseases and particularly ageing.
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Affiliation(s)
- Penelope A. Mason
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Lynne S. Cox
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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Yamaguchi T, Taguchi A, Watanabe K, Orii H. DEADSouth protein localizes to germ plasm and is required for the development of primordial germ cells in Xenopus laevis. Biol Open 2012; 2:191-9. [PMID: 23429978 PMCID: PMC3575653 DOI: 10.1242/bio.20123111] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/11/2012] [Indexed: 12/26/2022] Open
Abstract
DEADSouth mRNA is a component of germ plasm in Xenopus laevis and encodes a DDX25 DEAD-box RNA helicase. To determine the intracellular localization of DEADSouth protein, we injected mRNA encoding DEADSouth tagged with mCherry fluorescent protein into fertilized eggs from transgenic Xenopus expressing EGFP fused with a mitochondrial targeting signal. The DEADSouth-mCherry fusion protein was localized to the germ plasm, a mitochondria-rich region in primordial germ cells (PGCs). DEADSouth overexpression resulted in a reduction of PGC numbers after stage 20. Conversely, DEADSouth knockdown using an antisense locked nucleic acid gapmer inhibited movement of the germ plasm from the cortex to the perinuclear region, resulting in inhibition of PGC division at stage 12 and a decrease in PGC numbers at later stages. The knockdown phenotype was rescued by intact DEADSouth mRNA, but not mutant mRNA encoding inactive DEADSouth helicase. Surprisingly, it was also rescued by mouse vasa homolog and Xenopus vasa-like gene 1 mRNAs that encode DDX4 RNA helicases. The rescue was dependent on the 3' untranslated region (3'UTR) of DEADSouth mRNA, which was used for PGC-specific expression. The 3'UTR contributed to localization of the injected mRNA to the germ plasm, resulting in effective localization of DEADSouth protein. These results demonstrate that localization of DEADSouth helicase to the germ plasm is required for proper PGC development in Xenopus laevis.
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Affiliation(s)
- Takeshi Yamaguchi
- Department of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori, Akou-gun , Hyogo 678-1297 , Japan
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Medioni C, Mowry K, Besse F. Principles and roles of mRNA localization in animal development. Development 2012; 139:3263-76. [PMID: 22912410 DOI: 10.1242/dev.078626] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Intracellular targeting of mRNAs has long been recognized as a means to produce proteins locally, but has only recently emerged as a prevalent mechanism used by a wide variety of polarized cell types. Localization of mRNA molecules within the cytoplasm provides a basis for cell polarization, thus underlying developmental processes such as asymmetric cell division, cell migration, neuronal maturation and embryonic patterning. In this review, we describe and discuss recent advances in our understanding of both the regulation and functions of RNA localization during animal development.
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Affiliation(s)
- Caroline Medioni
- Institute of Biology Valrose, University of Nice-Sophia Antipolis/UMR7277 CNRS/UMR1091 INSERM, Parc Valrose, 06108 Nice Cedex 2, France
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Houston DW. Cortical rotation and messenger RNA localization in Xenopus axis formation. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 1:371-88. [PMID: 23801488 DOI: 10.1002/wdev.29] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In Xenopus eggs, fertilization initiates a rotational movement of the cortex relative to the cytoplasm, resulting in the transport of critical determinants to the future dorsal side of the embryo. Cortical rotation is mediated by microtubules, resulting in activation of the Wnt/β-catenin signaling pathway and expression of organizer genes on the dorsal side of the blastula. Similar cytoplasmic localizations resulting in β-catenin activation occur in many chordate embryos, suggesting a deeply conserved mechanism for patterning early embryos. This review summarizes the experimental evidence for the molecular basis of this model, focusing on recent maternal loss-of-function studies that shed light on two main unanswered questions: (1) what regulates microtubule assembly during cortical rotation and (2) how is Wnt/β-catenin signaling activated dorsally? In addition, as these processes depend on vegetally localized molecules in the oocyte, the mechanisms of RNA localization and novel roles for localized RNAs in axis formation are discussed. The work reviewed here provides a beginning framework for understanding the coupling of asymmetry in oogenesis with the establishment of asymmetry in the embryo.
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