1
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Wilson CA, Batzel P, Postlethwait JH. Direct male development in chromosomally ZZ zebrafish. Front Cell Dev Biol 2024; 12:1362228. [PMID: 38529407 PMCID: PMC10961373 DOI: 10.3389/fcell.2024.1362228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 02/20/2024] [Indexed: 03/27/2024] Open
Abstract
The genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish (Danio rerio), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males. To understand mechanisms of gonad development in NA zebrafish, we studied histology and single cell transcriptomics in developing ZZ and ZW fish. ZW fish developed oocytes by 22 days post-fertilization (dpf) but ZZ fish directly formed testes, avoiding a juvenile ovary phase. Gonads of some ZW and WW fish, however, developed oocytes that died as the gonad became a testis, mimicking AB fish, suggesting that the gynogenetically derived AB strain is chromosomally WW. Single-cell RNA-seq of 19dpf gonads showed similar cell types in ZZ and ZW fish, including germ cells, precursors of gonadal support cells, steroidogenic cells, interstitial/stromal cells, and immune cells, consistent with a bipotential juvenile gonad. In contrast, scRNA-seq of 30dpf gonads revealed that cells in ZZ gonads had transcriptomes characteristic of testicular Sertoli, Leydig, and germ cells while ZW gonads had granulosa cells, theca cells, and developing oocytes. Hematopoietic and vascular cells were similar in both sex genotypes. These results show that juvenile NA zebrafish initially develop a bipotential gonad; that a factor on the NA W chromosome, or fewer than two Z chromosomes, is essential to initiate oocyte development; and without the W factor, or with two Z doses, NA gonads develop directly into testes without passing through the juvenile ovary stage. Sex determination in AB and TU strains mimics NA ZW and WW zebrafish, suggesting loss of the Z chromosome during domestication. Genetic analysis of the NA strain will facilitate our understanding of the evolution of sex determination mechanisms.
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2
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Wilson CA, Batzel P, Postlethwait JH. Direct Male Development in Chromosomally ZZ Zebrafish. bioRxiv 2023:2023.12.27.573483. [PMID: 38234788 PMCID: PMC10793451 DOI: 10.1101/2023.12.27.573483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
The genetics of sex determination varies across taxa, sometimes even within a species. Major domesticated strains of zebrafish ( Danio rerio ), including AB and TU, lack a strong genetic sex determining locus, but strains more recently derived from nature, like Nadia (NA), possess a ZZ male/ZW female chromosomal sex-determination system. AB strain fish pass through a juvenile ovary stage, forming oocytes that survive in fish that become females but die in fish that become males. To understand mechanisms of gonad development in NA zebrafish, we studied histology and single cell transcriptomics in developing ZZ and ZW fish. ZW fish developed oocytes by 22 days post-fertilization (dpf) but ZZ fish directly formed testes, avoiding a juvenile ovary phase. Gonads of some ZW and WW fish, however, developed oocytes that died as the gonad became a testis, mimicking AB fish, suggesting that the gynogenetically derived AB strain is chromosomally WW. Single-cell RNA-seq of 19dpf gonads showed similar cell types in ZZ and ZW fish, including germ cells, precursors of gonadal support cells, steroidogenic cells, interstitial/stromal cells, and immune cells, consistent with a bipotential juvenile gonad. In contrast, scRNA-seq of 30dpf gonads revealed that cells in ZZ gonads had transcriptomes characteristic of testicular Sertoli, Leydig, and germ cells while ZW gonads had granulosa cells, theca cells, and developing oocytes. Hematopoietic and vascular cells were similar in both sex genotypes. These results show that juvenile NA zebrafish initially develop a bipotential gonad; that a factor on the NA W chromosome or fewer than two Z chromosomes is essential to initiate oocyte development; and without the W factor or with two Z doses, NA gonads develop directly into testes without passing through the juvenile ovary stage. Sex determination in AB and TU strains mimics NA ZW and WW zebrafish, suggesting loss of the Z chromosome during domestication. Genetic analysis of the NA strain will facilitate our understanding of the evolution of sex determination mechanisms.
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3
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Divyanshi, Yang J. Germ plasm dynamics during oogenesis and early embryonic development in Xenopus and zebrafish. Mol Reprod Dev 2023. [PMID: 38126950 DOI: 10.1002/mrd.23718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 11/09/2023] [Accepted: 11/12/2023] [Indexed: 12/23/2023]
Abstract
Specification of the germline and its segregation from the soma mark one of the most crucial events in the lifetime of an organism. In different organisms, this specification can occur through either inheritance or inductive mechanisms. In species such as Xenopus and zebrafish, the specification of primordial germ cells relies on the inheritance of maternal germline determinants that are synthesized and sequestered in the germ plasm during oogenesis. In this review, we discuss the formation of the germ plasm, how germline determinants are recruited into the germ plasm during oogenesis, and the dynamics of the germ plasm during oogenesis and early embryonic development.
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Affiliation(s)
- Divyanshi
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
| | - Jing Yang
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
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4
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Ichikawa K, Horiuchi H. Fate Decisions of Chicken Primordial Germ Cells (PGCs): Development, Integrity, Sex Determination, and Self-Renewal Mechanisms. Genes (Basel) 2023; 14:genes14030612. [PMID: 36980885 PMCID: PMC10048776 DOI: 10.3390/genes14030612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023] Open
Abstract
Primordial germ cells (PGCs) are precursor cells of sperm and eggs. The fate decisions of chicken PGCs in terms of their development, integrity, and sex determination have unique features, thereby providing insights into evolutionary developmental biology. Additionally, fate decisions in the context of a self-renewal mechanism have been applied to establish culture protocols for chicken PGCs, enabling the production of genome-edited chickens and the conservation of genetic resources. Thus, studies on the fate decisions of chicken PGCs have significantly contributed to both academic and industrial development. Furthermore, studies on fate decisions have rapidly advanced owing to the recent development of essential research technologies, such as genome editing and RNA sequencing. Here, we reviewed the status of fate decisions of chicken PGCs and provided insight into other important research issues that require attention.
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Affiliation(s)
- Kennosuke Ichikawa
- Genome Editing Innovation Center, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima 739-0046, Hiroshima, Japan
- Correspondence:
| | - Hiroyuki Horiuchi
- Genome Editing Innovation Center, Hiroshima University, 3-10-23 Kagamiyama, Higashi-Hiroshima 739-0046, Hiroshima, Japan
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Hiroshima, Japan
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5
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Naraine R, Iegorova V, Abaffy P, Franek R, Soukup V, Psenicka M, Sindelka R. Evolutionary conservation of maternal RNA localization in fishes and amphibians revealed by TOMO-Seq. Dev Biol 2022:S0012-1606(22)00130-0. [PMID: 35752299 DOI: 10.1016/j.ydbio.2022.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Yamanaka S, Okada Y, Furuta T, Kinoshita M. Establishment of culture and microinjection methods for false clownfish embryos without parental care. Dev Growth Differ 2021; 63:459-466. [PMID: 34786704 DOI: 10.1111/dgd.12759] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 11/27/2022]
Abstract
Anemonefish, including the false clownfish Amphiprion ocellaris, are attractive model organisms because of their unique features, such as sex change and brilliant color patterns in mutants. However, anemonefish are not widely used to study gene function using reverse genetic approaches owing to microinjection difficulties and subsequent rearing and hatching of embryos without parental care. A. ocellaris embryos are spawned on a hard substrate and cared for by their parents until hatching. However, the eggs need to be detached from the substrate and raised without their parents to perform successful microinjection. We established a method to culture and hatch A. ocellaris embryos without spawning substrates or parental care. We found that changing water and generating water flow are critical for culturing the embryos, and that water flow (as physical stimulation) and complete darkness in the dark period are necessary for successful hatching. We further investigated the effectiveness of microinjection into the yolk sac of fertilized eggs rather than into the cytoplasm, which makes microinjection easier. A reporter RNA injected into the yolk sac was transferred to the cytoplasm and translated, indicating that yolk sac microinjection is an efficient alternative as has been used for zebrafish. These findings highlight the potential of A. ocellaris as an experimental model organism for reverse genetics, and our methods could be applied to other anemonefish species.
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Affiliation(s)
- Sakuto Yamanaka
- Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yosuke Okada
- Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takeshi Furuta
- Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry, Chiba, Japan
| | - Masato Kinoshita
- Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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7
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Hansen CL, Chamberlain TJ, Trevena RL, Kurek JE, Pelegri F. Conserved germ plasm characteristics across the Danio and Devario lineages. Genesis 2021; 59:e23452. [PMID: 34617657 DOI: 10.1002/dvg.23452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/26/2021] [Accepted: 08/29/2021] [Indexed: 11/06/2022]
Abstract
In many animal species, germ cell specification requires the inheritance of germ plasm, a biomolecular condensate containing maternally derived RNAs and proteins. Most studies of germ plasm composition and function have been performed in widely evolutionarily divergent model organisms, such as Caenorhabditis elegans, Drosophila, Xenopus laevis, and Danio rerio (zebrafish). In zebrafish, 12 RNAs localize to germ plasm at the furrows of the early embryo. Here, we tested for the presence of these RNAs in three additional species within the Danionin clade: Danio kyathit, Danio albolineatus, and Devario aequipinnatus. By visualizing nanos RNA, we find that germ plasm segregation patterns during early embryogenesis are conserved across these species. Ten additional germ plasm RNAs exhibit localization at the furrows of early embryos in all three non-zebrafish Danionin species, consistent with germ plasm localization. One component of zebrafish germ plasm, ca15b, lacked specific localization in embryos of the more distantly related D. aequipinnatus. Our findings show that within a subset of closely related Danionin species, the vast majority of germ plasm RNA components are conserved. At the same time, the lack of ca15b localization in D. aequipinnatus germ plasm highlights the potential for the divergence of germ plasm composition across a restricted phylogenetic space.
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Affiliation(s)
- Christina L Hansen
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Trevor J Chamberlain
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Ryan L Trevena
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Jacob E Kurek
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin, USA
| | - Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin, USA
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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Zhao Y, Du Y, Ge Q, Yan F, Wei S. Identification and expression analysis of Dazl homologue in Cynops cyanurus. ZYGOTE 2021;:1-6. [PMID: 34315561 DOI: 10.1017/S0967199421000538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The Dazl (deleted in azoospermia-like) gene encodes an RNA-binding protein containing an RNA recognition motif (RRM) and a DAZ motif. Dazl is essential for gametogenesis in vertebrates. In this study, we report the cloning of Dazl cDNA from Cynops cyanurus. Ccdazl mRNA showed a germline-specific expression pattern as expected. Ccdazl expression gradually decreased during oogenesis, suggesting that it may be involved in oocyte development. Phylogenetic analysis revealed that the Ccdazl protein shares conserved motifs/domains with Dazl proteins from other species. Cloning of Ccdazl provides a new tool to carry out comparative studies of germ cell development in amphibians.
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10
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Ren F, Miao R, Xiao R, Mei J. m 6A reader Igf2bp3 enables germ plasm assembly by m 6A-dependent regulation of gene expression in zebrafish. Sci Bull (Beijing) 2021; 66:1119-1128. [PMID: 36654345 DOI: 10.1016/j.scib.2021.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 09/13/2020] [Accepted: 10/27/2020] [Indexed: 01/20/2023]
Abstract
Bucky ball (Buc) is involved in germ plasm (GP) assembly during early zebrafish development by regulating GP mRNA expression via an unknown mechanism. The present study demonstrates that an m6A reader Igf2bp3 interacts and colocalizes with Buc in the GP. Similar to the loss of Buc, the genetic deletion of maternal igf2bp3 in zebrafish leads to abnormal GP assembly and insufficient germ cell specification, which can be partially restored by the injection of igf2bp3 mRNA. Igf2bp3 binds to m6A-modified GP-organizer and GP mRNAs in an m6A-dependent manner and prevents their degradation. These findings indicate that the functions of Igf2bp3, a direct effector protein of Buc, in GP mRNA expression and GP assembly involve m6A-dependent regulation; these results emphasize a critical role of m6A modification in the process of GP assembly.
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Affiliation(s)
- Fan Ren
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Ran Miao
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China
| | - Rui Xiao
- Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan 430071, China; Department of Hematology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China.
| | - Jie Mei
- College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
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11
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Bertho S, Clapp M, Banisch TU, Bandemer J, Raz E, Marlow FL. Zebrafish dazl regulates cystogenesis and germline stem cell specification during the primordial germ cell to germline stem cell transition. Development 2021; 148:dev187773. [PMID: 33722898 PMCID: PMC8077517 DOI: 10.1242/dev.187773] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/04/2021] [Indexed: 01/14/2023]
Abstract
Fertility and gamete reserves are maintained by asymmetric divisions of the germline stem cells to produce new stem cells or daughters that differentiate as gametes. Before entering meiosis, differentiating germ cells (GCs) of sexual animals typically undergo cystogenesis. This evolutionarily conserved process involves synchronous and incomplete mitotic divisions of a GC daughter (cystoblast) to generate sister cells connected by intercellular bridges that facilitate the exchange of materials to support rapid expansion of the gamete progenitor population. Here, we investigated cystogenesis in zebrafish and found that early GCs are connected by ring canals, and show that Deleted in azoospermia-like (Dazl), a conserved vertebrate RNA-binding protein (Rbp), is a regulator of this process. Analysis of dazl mutants revealed the essential role of Dazl in regulating incomplete cytokinesis, germline cyst formation and germline stem cell specification before the meiotic transition. Accordingly, dazl mutant GCs form defective ring canals, and ultimately remain as individual cells that fail to differentiate as meiocytes. In addition to promoting cystoblast divisions and meiotic entry, dazl is required for germline stem cell establishment and fertility.
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Affiliation(s)
- Sylvain Bertho
- Department of Cell, Developmental and Regenerative Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place Box 1020 New York, NY 10029-6574, USA
| | - Mara Clapp
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Torsten U. Banisch
- Institute of Cell Biology Center for Molecular Biology of Inflammation, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
- New York University School of Medicine, Department of Cell Biology, New York, NY 10012, USA
| | - Jan Bandemer
- Institute of Cell Biology Center for Molecular Biology of Inflammation, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Erez Raz
- Institute of Cell Biology Center for Molecular Biology of Inflammation, Von-Esmarch-Str. 56, D-48149 Muenster, Germany
| | - Florence L. Marlow
- Department of Cell, Developmental and Regenerative Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place Box 1020 New York, NY 10029-6574, USA
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Abstract
The transmission of genetic information from one generation to another is crucial for survival of animal species. This is accomplished by the induction of primordial germ cells (PGCs) that will eventually establish the germline. In some animals the germline is induced by signals in gastrula, whereas in others it is specified by inheritance of maternal determinants, known as germ plasm. In zebrafish, aggregation and compaction of maternally derived germ plasm during the first several embryonic cell cycles is essential for generation of PGCs. These processes are controlled by cellular functions associated with the cellular division apparatus. Ribonucleoparticles containing germ plasm components are bound to both the ends of astral microtubules and a dynamic F-actin network through a mechanism integrated with that which drives the cell division program. In this chapter we discuss the role that modifications of the cell division apparatus, including the cytoskeleton and cytoskeleton-associated proteins, play in the regulation of zebrafish germ plasm assembly.
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Affiliation(s)
- Cara E Moravec
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States
| | - Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, United States.
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Skvortsova K, Tarbashevich K, Stehling M, Lister R, Irimia M, Raz E, Bogdanovic O. Retention of paternal DNA methylome in the developing zebrafish germline. Nat Commun 2019; 10:3054. [PMID: 31296860 PMCID: PMC6624265 DOI: 10.1038/s41467-019-10895-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/31/2019] [Indexed: 01/08/2023] Open
Abstract
Two waves of DNA methylation reprogramming occur during mammalian embryogenesis; during preimplantation development and during primordial germ cell (PGC) formation. However, it is currently unclear how evolutionarily conserved these processes are. Here we characterise the DNA methylomes of zebrafish PGCs at four developmental stages and identify retention of paternal epigenetic memory, in stark contrast to the findings in mammals. Gene expression profiling of zebrafish PGCs at the same developmental stages revealed that the embryonic germline is defined by a small number of markers that display strong developmental stage-specificity and that are independent of DNA methylation-mediated regulation. We identified promoters that are specifically targeted by DNA methylation in somatic and germline tissues during vertebrate embryogenesis and that are frequently misregulated in human cancers. Together, these detailed methylome and transcriptome maps of the zebrafish germline provide insight into vertebrate DNA methylation reprogramming and enhance our understanding of the relationships between germline fate acquisition and oncogenesis.
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Affiliation(s)
- Ksenia Skvortsova
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia
| | - Katsiaryna Tarbashevich
- Institute of Cell Biology, Center for Molecular Biology of Inflammation, University of Münster, Münster, 48149, Germany
| | - Martin Stehling
- Flow Cytometry Unit, Max-Planck-Institute for Molecular Biomedicine, Roentgenstraße 20, 48149, Münster, Germany
| | - Ryan Lister
- ARC CoE Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Perth, WA, 6009, Australia
- Molecular Medicine Division, Harry Perkins Institute of Medical Research, Perth, WA, 6009, Australia
| | - Manuel Irimia
- Centre for Genomic Regulation, The Barcelona Institute for Science and Technology, Barcelona, 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, 08002, Spain
- ICREA, Barcelona, 08010, Spain
| | - Erez Raz
- Institute of Cell Biology, Center for Molecular Biology of Inflammation, University of Münster, Münster, 48149, Germany
| | - Ozren Bogdanovic
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, 2010, Australia.
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2010, Australia.
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Abstract
From the beginning of oogenesis, oocytes accumulate tens of thousands of mRNAs for promoting oocyte growth and development. A large number of these mRNAs are translationally repressed and localized within the oocyte cytoplasm. Translational activation of these dormant mRNAs at specific sites and timings plays central roles in driving progression of the meiotic cell cycle, axis formation, mitotic cleavages, transcriptional initiation, and morphogenesis. Regulation of the localization and temporal translation of these mRNAs has been shown to rely on cis-acting elements in the mRNAs and trans-acting factors recognizing and binding to the elements. Recently, using model vertebrate zebrafish, localization itself and formation of physiological structures such as RNA granules have been shown to coordinate the accurate timings of translational activation of dormant mRNAs. This subcellular regulation of mRNAs is also utilized in other animals including mouse. In this chapter, we review fundamental roles of temporal regulation of mRNA translation in oogenesis and early development and then focus on the mechanisms of mRNA regulation in the oocyte cytoplasm by which the activation of dormant mRNAs at specific timings is achieved.
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15
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Eno C, Hansen CL, Pelegri F. Aggregation, segregation, and dispersal of homotypic germ plasm RNPs in the early zebrafish embryo. Dev Dyn 2019; 248:306-318. [PMID: 30741457 DOI: 10.1002/dvdy.18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/07/2019] [Accepted: 01/30/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In zebrafish and many other organisms, specification of primordial germ cells (PGCs) requires the transmission of maternally-derived germ plasm. Zebrafish germ plasm ribonucleoparticles (RNPs) aggregate along the cleavage furrows during the first several cell cycles, segregate asymmetrically during the cleavage stages, and undergo cytoplasmic dispersal in the late blastula. RESULTS For all tested germ plasm RNAs [carbonic anhydrase 15b (ca15b), deleted in azoospermia-like (dazl), dead end (dnd), nanos 3 (nos3), regulator of G-protein signaling14a (rgs14a), and vasa/DEAD box polypeptide 4 (vasa/ddx4)], RNPs are homotypic (containing a single RNA type), with RNPs packing tightly yet remaining distinct within germ plasm aggregates. Homotypic clustering of RNAs within RNPs is observed before aggregation in the cortex and is maintained through germ plasm recruitment, asymmetric segregation and RNP dispersal. We also identify a step of germ plasm fragmentation during the cleavage stages that precedes RNP dispersal. CONCLUSIONS Our findings suggest that germ plasm aggregates act as subcellular compartments that temporarily collect and carry single RNA-type RNPs from fertilization until their cytoplasmic dispersal in PGCs at the end of the blastula period, and describe a previously unknown fragmentation step that allows for an increase in the pool of germ plasm-carrying cells, presumably PGCs. Developmental Dynamics 248:306-318, 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Celeste Eno
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin
| | - Christina L Hansen
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin
| | - Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin - Madison, Madison, Wisconsin
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16
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Yi X, Yu J, Ma C, Dong G, Shi W, Li H, Li L, Luo L, Sampath K, Ruan H, Huang H. The effector of Hippo signaling, Taz, is required for formation of the micropyle and fertilization in zebrafish. PLoS Genet 2019; 15:e1007408. [PMID: 30608921 PMCID: PMC6334976 DOI: 10.1371/journal.pgen.1007408] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 01/16/2019] [Accepted: 12/10/2018] [Indexed: 11/18/2022] Open
Abstract
The mechanisms that ensure fertilization of egg by a sperm are not fully understood. In all teleosts, a channel called the 'micropyle' is the only route of entry for sperm to enter and fertilize the egg. The micropyle forms by penetration of the vitelline envelope by a single specialized follicle cell, the micropylar cell. The mechanisms underlying micropylar cell specification and micropyle formation are poorly understood. Here, we show that an effector of the Hippo signaling pathway, the Transcriptional co-activator with a PDZ-binding domain (Taz), plays crucial roles in micropyle formation and fertilization in zebrafish (Danio rerio). Genome editing mutants affecting taz can grow to adults. However, eggs from homozygous taz females are not fertilized even though oocytes in mutant females are histologically normal with intact animal-vegetal polarity, complete meiosis and proper ovulation. We find that taz mutant eggs have no micropyle. Taz protein is specifically enriched in mid-oogenesis in the micropylar cell located at the animal pole of wild type oocyte, where it might regulate the cytoskeleton. Taz protein and micropylar cells are not detected in taz mutant ovaries. Our work identifies a novel role for the Hippo/Taz pathway in micropylar cell specification in zebrafish, and uncovers the molecular basis of micropyle formation in teleosts.
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Affiliation(s)
- Xiaogui Yi
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Jia Yu
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Chao Ma
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Guoping Dong
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Wenpeng Shi
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Hongtao Li
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Li Li
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Lingfei Luo
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Karuna Sampath
- Cell & Developmental Biology Unit, Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Hua Ruan
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
| | - Honghui Huang
- Key Laboratory of Freshwater Fish Reproduction and Development, Ministry of Education, State Key Laboratory Breeding Base of Eco-Environments and Bio-Resources of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Beibei, Chongqing, China
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17
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Fuentes R, Letelier J, Tajer B, Valdivia LE, Mullins MC. Fishing forward and reverse: Advances in zebrafish phenomics. Mech Dev 2018; 154:296-308. [PMID: 30130581 PMCID: PMC6289646 DOI: 10.1016/j.mod.2018.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 08/06/2018] [Accepted: 08/17/2018] [Indexed: 12/15/2022]
Abstract
Understanding how the genome instructs the phenotypic characteristics of an organism is one of the major scientific endeavors of our time. Advances in genetics have progressively deciphered the inheritance, identity and biological relevance of genetically encoded information, contributing to the rise of several, complementary omic disciplines. One of them is phenomics, an emergent area of biology dedicated to the systematic multi-scale analysis of phenotypic traits. This discipline provides valuable gene function information to the rapidly evolving field of genetics. Current molecular tools enable genome-wide analyses that link gene sequence to function in multi-cellular organisms, illuminating the genome-phenome relationship. Among vertebrates, zebrafish has emerged as an outstanding model organism for high-throughput phenotyping and modeling of human disorders. Advances in both systematic mutagenesis and phenotypic analyses of embryonic and post-embryonic stages in zebrafish have revealed the function of a valuable collection of genes and the general structure of several complex traits. In this review, we summarize multiple large-scale genetic efforts addressing parental, embryonic, and adult phenotyping in the zebrafish. The genetic and quantitative tools available in the zebrafish model, coupled with the broad spectrum of phenotypes that can be assayed, make it a powerful model for phenomics, well suited for the dissection of genotype-phenotype associations in development, physiology, health and disease.
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Affiliation(s)
- Ricardo Fuentes
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joaquín Letelier
- Centro Andaluz de Biología del Desarrollo (CSIC/UPO/JA), Seville, Spain; Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Benjamin Tajer
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Leonardo E Valdivia
- Center for Integrative Biology, Facultad de Ciencias, Universidad Mayor, Santiago, Chile.
| | - Mary C Mullins
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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18
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Dingare C, Niedzwetzki A, Klemmt PA, Godbersen S, Fuentes R, Mullins MC, Lecaudey V. The Hippo pathway effector Taz is required for cell morphogenesis and fertilization in zebrafish. Development 2018; 145:dev.167023. [PMID: 30327325 DOI: 10.1242/dev.167023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/09/2018] [Indexed: 12/12/2022]
Abstract
Hippo signaling is a critical pathway that integrates extrinsic and intrinsic mechanical cues to regulate organ size. Despite its essential role in organogenesis, little is known about its role in cell fate specification and differentiation. Here, we unravel a novel and unexpected role of the Hippo pathway effector Taz (wwtr1) in controlling the size, shape and fate of a unique cell in the zebrafish ovary. We show that wwtr1 mutant females are infertile. In teleosts, fertilization occurs through the micropyle, a funnel-like opening in the chorion, formed by a unique enlarged follicle cell, the micropylar cell (MC). We describe here, for the first time, the mechanism that underlies the differentiation of the MC. Our genetic analyses show that Taz is essential for MC fate acquisition and subsequent micropyle formation in zebrafish. We identify Taz as the first bona fide MC marker and show that Taz is specifically and strongly enriched in the MC precursor. Altogether, we performed the first genetic and molecular characterization of the MC and propose that Taz is a key regulator of MC fate.This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Chaitanya Dingare
- Institute of Cell Biology and Neuroscience, Department of Developmental Biology of Vertebrates, Goethe Universität Frankfurt am Main, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany.,Developmental Biology, Institute for Biology I, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Alina Niedzwetzki
- Institute of Cell Biology and Neuroscience, Department of Developmental Biology of Vertebrates, Goethe Universität Frankfurt am Main, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Petra A Klemmt
- Institute of Cell Biology and Neuroscience, Department of Developmental Biology of Vertebrates, Goethe Universität Frankfurt am Main, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Svenja Godbersen
- Developmental Biology, Institute for Biology I, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
| | - Ricardo Fuentes
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Mary C Mullins
- University of Pennsylvania Perelman School of Medicine, Department of Cell and Developmental Biology, 421 Curie Blvd., Philadelphia, PA 19104, USA
| | - Virginie Lecaudey
- Institute of Cell Biology and Neuroscience, Department of Developmental Biology of Vertebrates, Goethe Universität Frankfurt am Main, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany .,Developmental Biology, Institute for Biology I, Faculty of Biology, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany
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19
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Ma L, Strickler AG, Parkhurst A, Yoshizawa M, Shi J, Jeffery WR. Maternal genetic effects in Astyanax cavefish development. Dev Biol 2018; 441:209-220. [PMID: 30031754 DOI: 10.1016/j.ydbio.2018.07.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/28/2018] [Accepted: 07/16/2018] [Indexed: 12/19/2022]
Abstract
The role of maternal factors in the evolution of development is poorly understood. Here we describe the use of reciprocal hybridization between the surface dwelling (surface fish, SF) and cave dwelling (cavefish, CF) morphs of the teleost Astyanax mexicanus to investigate the roles of maternal genetic effects in cavefish development. Reciprocal hybridization, a procedure in which F1 hybrids are generated by fertilizing SF eggs with CF sperm (SF × CF hybrids) and CF eggs with SF sperm (CF × SF hybrids), revealed that the CF degenerative eye phenotype showed maternal genetic effects. The eyes of CF × SF hybrids resembled the degenerate eyes of CF in showing ventral reduction of the retina and corresponding displacement of the lens within the optic cup, a smaller lens and eyeball, more lens apoptosis, a smaller cartilaginous sclera, and lens-specific gene expression characteristics compared to SF × CF hybrids, which showed eye and lens gene expression phenotypes resembling SF. In contrast, reciprocal hybridization failed to support roles for maternal genetic effects in the CF regressive pigmentation phenotype or in CF constructive changes related to enhanced jaw development. Maternal transcripts encoded by the pou2f1b, runx2b, and axin1 genes, which are involved in determining ventral embryonic fates, were increased in unfertilized CF eggs. In contrast, maternal mRNAs encoded by the ß-catenin and syntabulin genes, which control dorsal embryonic fates, showed similar expression levels in unfertilized SF and CF eggs. Furthermore, maternal transcripts of a sonic hedgehog gene were detected in SF and CF eggs and early cleaving embryos. This study reveals that CF eye degeneration is controlled by changes in maternal factors produced during oogenesis and introduces A. mexicanus as a model system for studying the role of maternal changes in the evolution of development.
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Affiliation(s)
- Li Ma
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Allen G Strickler
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Amy Parkhurst
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Masato Yoshizawa
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Janet Shi
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - William R Jeffery
- Department of Biology, University of Maryland, College Park, MD 20742, USA.
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20
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Takei N, Nakamura T, Kawamura S, Takada Y, Satoh Y, Kimura AP, Kotani T. High-Sensitivity and High-Resolution In Situ Hybridization of Coding and Long Non-coding RNAs in Vertebrate Ovaries and Testes. Biol Proced Online 2018; 20:6. [PMID: 29507535 PMCID: PMC5831722 DOI: 10.1186/s12575-018-0071-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/29/2018] [Indexed: 12/22/2022] Open
Abstract
Background Subcellular localization of coding and non-coding RNAs has emerged as major regulatory mechanisms of gene expression in various cell types and many organisms. However, techniques that enable detection of the subcellular distribution of these RNAs with high sensitivity and high resolution remain limited, particularly in vertebrate adult tissues and organs. In this study, we examined the expression and localization of mRNAs encoding Pou5f1/Oct4, Mos, Cyclin B1 and Deleted in Azoospermia-like (Dazl) in zebrafish and mouse ovaries by combining tyramide signal amplification (TSA)-based in situ hybridization with paraffin sections which can preserve cell morphology of tissues and organs at subcellular levels. In addition, the distribution of a long non-coding RNA (lncRNA), lncRNA-HSVIII, in mouse testes was examined by the same method. Results The mRNAs encoding Mos, Cyclin B1 and Dazl were found to assemble into distinct granules that were distributed in different subcellular regions of zebrafish and mouse oocytes, suggesting conserved and specific regulations of these mRNAs. The lncRNA-HSVIII was first detected in the nucleus of spermatocytes at prophase I of the meiotic cell cycle and was then found in the cytoplasm of round spermatids, revealing expression patterns of lncRNA during germ cell development. Collectively, the in situ hybridization method demonstrated in this study achieved the detection and comparison of precise distribution patterns of coding and non-coding RNAs at subcellular levels in single cells of adult tissues and organs. Conclusions This high-sensitivity and high-resolution in situ hybridization is applicable to many vertebrate species and to various tissues and organs and will be useful for studies on the subcellular regulation of gene expression at the level of RNA localization. Electronic supplementary material The online version of this article (10.1186/s12575-018-0071-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Natsumi Takei
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Takuma Nakamura
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Shohei Kawamura
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Yuki Takada
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Yui Satoh
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan
| | - Atsushi P Kimura
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan.,2Department of Biological Sciences, Faculty of Science, Hokkaido University, North 10 West 8, Sapporo, Hokkaido 060-0810 Japan
| | - Tomoya Kotani
- 1Biosystems Science Course, Graduate School of Life Science, Hokkaido University, Sapporo, 060-0810 Japan.,2Department of Biological Sciences, Faculty of Science, Hokkaido University, North 10 West 8, Sapporo, Hokkaido 060-0810 Japan
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21
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Shao M, Wang M, Liu YY, Ge YW, Zhang YJ, Shi DL. Vegetally localised Vrtn functions as a novel repressor to modulate bmp2b transcription during dorsoventral patterning in zebrafish. Development 2017; 144:3361-3374. [PMID: 28928283 DOI: 10.1242/dev.152553] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 08/15/2017] [Indexed: 02/03/2023]
Abstract
The vegetal pole cytoplasm represents a crucial source of maternal dorsal determinants for patterning the dorsoventral axis of the early embryo. Removal of the vegetal yolk in the zebrafish fertilised egg before the completion of the first cleavage results in embryonic ventralisation, but removal of this part at the two-cell stage leads to embryonic dorsalisation. How this is achieved remains unknown. Here, we report a novel mode of maternal regulation of BMP signalling during dorsoventral patterning in zebrafish. We identify Vrtn as a novel vegetally localised maternal factor with dorsalising activity and rapid transport towards the animal pole region after fertilisation. Co-injection of vrtn mRNA with vegetal RNAs from different cleavage stages suggests the presence of putative vegetally localised Vrtn antagonists with slower animal pole transport. Thus, vegetal ablation at the two-cell stage could remove most of the Vrtn antagonists, and allows Vrtn to produce the dorsalising effect. Mechanistically, Vrtn binds a bmp2b regulatory sequence and acts as a repressor to inhibit its zygotic transcription. Analysis of maternal-zygotic vrtn mutants further shows that Vrtn is required to constrain excessive bmp2b expression in the margin. Our work unveils a novel maternal mechanism regulating zygotic BMP gradient in dorsoventral patterning.
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Affiliation(s)
- Ming Shao
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China
| | - Min Wang
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China
| | - Yuan-Yuan Liu
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China
| | - Yi-Wen Ge
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China
| | - Yan-Jun Zhang
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China
| | - De-Li Shi
- School of Life Science, Shandong University, 27 Shanda Nan road, Jinan 250100, China .,Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR7622, IBPS-Developmental Biology Laboratory, 75005 Paris, France
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22
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Abstract
Fully grown oocytes arrest meiosis at prophase I and deposit maternal RNAs. A subset of maternal transcripts is stored in a dormant state in the oocyte, and the timely driven translation of specific mRNAs guides meiotic progression, the oocyte-embryo transition, and early embryo development. In the absence of transcription, the regulation of gene expression in oocytes is controlled almost exclusively at the level of transcriptome and proteome stabilization and at the level of protein synthesis.This chapter focuses on the recent findings on RNA distribution related to the temporal and spatial translational control of the meiotic cycle progression in mammalian oocytes. We discuss the most relevant mechanisms involved in the organization of the oocyte's maternal transcriptome storage and localization, and the regulation of translation, in correlation with the regulation of oocyte meiotic progression.
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23
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Machaty Z, Miller AR, Zhang L. Egg Activation at Fertilization. In: Pelegri F, Danilchik M, Sutherland A, editors. Vertebrate Development. Cham: Springer International Publishing; 2017. pp. 1-47. [DOI: 10.1007/978-3-319-46095-6_1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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24
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Miranda-Rodríguez JR, Salas-Vidal E, Lomelí H, Zurita M, Schnabel D. RhoA/ROCK pathway activity is essential for the correct localization of the germ plasm mRNAs in zebrafish embryos. Dev Biol 2016; 421:27-42. [PMID: 27836552 DOI: 10.1016/j.ydbio.2016.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 10/01/2016] [Accepted: 11/01/2016] [Indexed: 01/01/2023]
Abstract
Zebrafish germ plasm is composed of mRNAs such as vasa and nanos and of proteins such as Bucky ball, all of which localize symmetrically in four aggregates at the distal region of the first two cleavage furrows. The coordination of actin microfilaments, microtubules and kinesin is essential for the correct localization of the germ plasm. Rho-GTPases, through their effectors, coordinate cytoskeletal dynamics. We address the participation of RhoA and its effector ROCK in germ plasm localization during the transition from two- to eight-cell embryos. We found that active RhoA is enriched along the cleavage furrow during the first two division cycles, whereas ROCK localizes at the distal region of the cleavage furrows in a similar pattern as the germ plasm mRNAs. Specific inhibition of RhoA and ROCK affected microtubules organization at the cleavage furrow; these caused the incorrect localization of the germ plasm mRNAs. The incorrect localization of the germ plasm led to a dramatic change in the number of germ cells during the blastula and 24hpf embryo stages without affecting any other developmental processes. We demonstrate that the Rho/ROCK pathway is intimately related to the determination of germ cells in zebrafish embryos.
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Affiliation(s)
- Jerónimo Roberto Miranda-Rodríguez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, Mexico
| | - Enrique Salas-Vidal
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, Mexico
| | - Hilda Lomelí
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, Mexico
| | - Mario Zurita
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, Mexico
| | - Denhi Schnabel
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, AP 510-3, Cuernavaca, Mor. 62250, Mexico.
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25
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Abstract
In zebrafish embryos, factors involved in both axis induction and primordial germ cell (PGC) development are localized to the vegetal pole of the egg. However, upon egg activation axis induction factors experience an asymmetric off-center shift whereas PGC factors undergo symmetric animally-directed movement. We examined the spatial relationship between the proposed dorsal genes wnt8a and grip2a and the PGC factor dazl at the vegetal cortex. We find that RNAs for these genes localize to different cortical depths, with the RNA for the PGC factor dazl at a deeper cortical level than those for axis-inducing factors. In addition, and in contrast to the role of microtubules in the long-range transport of dorsal determinants, we find that germ line determinant transport depends on the actin cytoskeleton. Our results support a model in which vegetal cortex differential RNA transport behavior is facilitated by RNA localization along cortical depth and differential coupling to cortical transport.
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Affiliation(s)
- Elaine Welch
- a Laboratory of Genetics; University of Wisconsin - Madison ; Madison , WI USA
| | - Francisco Pelegri
- a Laboratory of Genetics; University of Wisconsin - Madison ; Madison , WI USA
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26
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Li M, Zhu F, Li Z, Hong N, Hong Y. Dazl is a critical player for primordial germ cell formation in medaka. Sci Rep 2016; 6:28317. [PMID: 27328644 DOI: 10.1038/srep28317] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/01/2016] [Indexed: 11/27/2022] Open
Abstract
The DAZ family genes boule, daz and dazl have conserved functions in primordial germ cell (PGC) migration, germ stem cell proliferation, differentiation and meiosis progression. It has remained unknown whether this family is required for PGC formation in developing embryos. Our recent study in the fish medaka (Oryzias latipes) has defined dnd as the critical PGC specifier and predicted the presence of additional factors essential for PGC formation. Here we report that dazl is a second key player for medaka PGC formation. Dazl knockdown did not prevent PGC formation even in the absence of normal somatic structures. It turned out that a high level of Dazl protein was maternally supplied and persisted until gastrulation, and hardly affected by two antisense morpholino oligos targeting the dazl RNA translation. Importantly, microinjection of a Dazl antibody remarkably reduced the number of PGCs and even completely abolished PGC formation without causing detectable somatic abnormality. Therefore, medaka PGC formation requires the Dazl protein as maternal germ plasm component, offering first evidence that dazl is a critical player in PGC formation in vivo. Our results demonstrate that antibody neutralization is a powerful tool to study the roles of maternal protein factors in PGC development in vivo.
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27
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Lee HC, Choi HJ, Lee HG, Lim JM, Ono T, Han JY. DAZL Expression Explains Origin and Central Formation of Primordial Germ Cells in Chickens. Stem Cells Dev 2015; 25:68-79. [PMID: 26414995 DOI: 10.1089/scd.2015.0208] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The timing and biological events associated with germ cell specification in chickens have not been determined yet. In this study, we report the origin of primordial germ cells (PGCs) and germ plasm dynamics through investigation of the expression of the chicken homolog of deleted in azoospermia-like (cDAZL) gene during germ cell specification. Asymmetric localization of germ plasm in the center of oocytes from preovulatory follicle stages leads to PGCs being formed in the center. During cleavage stages, DAZL expression pattern changes from a subcellular localization to a diffuse form before and after zygotic genome activation. Meanwhile, PGCs exhibit transcriptional active status during their specification. In addition, knockdown studies of cDAZL, which result in reduced proliferation, aberrant gene expression profiles, and PGC apoptosis in vitro, suggest its possible roles for PGC formation in chicken. In conclusion, DAZL expression reveals formation and initial positioning of PGCs in chickens.
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Affiliation(s)
- Hyung Chul Lee
- 1 Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University , Seoul, Korea.,2 Department of Cell and Developmental Biology, University College London , London, United Kingdom
| | - Hee Jung Choi
- 1 Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University , Seoul, Korea
| | - Hyo Gun Lee
- 1 Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University , Seoul, Korea
| | - Jeong Mook Lim
- 1 Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University , Seoul, Korea
| | - Tamao Ono
- 3 Division of Animal Science, Faculty of Agriculture, Shinshu University , Nagano, Japan
| | - Jae Yong Han
- 1 Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University , Seoul, Korea.,4 Institute for Biomedical Sciences, Shinshu University , Nagano, Japan
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28
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Campbell PD, Heim AE, Smith MZ, Marlow FL. Kinesin-1 interacts with Bucky ball to form germ cells and is required to pattern the zebrafish body axis. Development 2015; 142:2996-3008. [PMID: 26253407 PMCID: PMC4582183 DOI: 10.1242/dev.124586] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/16/2015] [Indexed: 12/31/2022]
Abstract
In animals, specification of the primordial germ cells (PGCs), the stem cells of the germ line, is required to transmit genetic information from one generation to the next. Bucky ball (Buc) is essential for germ plasm (GP) assembly in oocytes, and its overexpression results in excess PGCs in zebrafish embryos. However, the mechanistic basis for the excess PGCs in response to Buc overexpression, and whether endogenous Buc functions during embryogenesis, are unknown. Here, we show that endogenous Buc, like GP and overexpressed Buc-GFP, accumulates at embryonic cleavage furrows. Furthermore, we show that the maternally expressed zebrafish Kinesin-1 Kif5Ba is a binding partner of Buc and that maternal kif5Ba (Mkif5Ba) plays an essential role in germline specification in vivo. Specifically, Mkif5Ba is required to recruit GP to cleavage furrows and thereby specifies PGCs. Moreover, Mkif5Ba is required to enrich Buc at cleavage furrows and for the ability of Buc to promote excess PGCs, providing mechanistic insight into how Buc functions to assemble embryonic GP. In addition, we show that Mkif5Ba is also essential for dorsoventral (DV) patterning. Specifically, Mkif5Ba promotes formation of the parallel vegetal microtubule array required to asymmetrically position dorsal determinants (DDs) towards the prospective dorsal side. Interestingly, whereas Syntabulin and wnt8a translocation depend on kif5Ba, grip2a translocation does not, providing evidence for two distinct mechanisms by which DDs might be asymmetrically distributed. These studies identify essential roles for maternal Kif5Ba in PGC specification and DV patterning, and provide mechanistic insight into Buc functions during early embryogenesis.
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Affiliation(s)
- Philip D Campbell
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Amanda E Heim
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Mordechai Z Smith
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
| | - Florence L Marlow
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461, USA
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Ramos-Ibeas P, Pericuesta E, Fernández-González R, Gutiérrez-Adán A, Ramírez MÁ. Characterisation of the deleted in azoospermia like (Dazl)-green fluorescent protein mouse model generated by a two-step embryonic stem cell-based strategy to identify pluripotent and germ cells. Reprod Fertil Dev 2015; 28:RD14253. [PMID: 25942058 DOI: 10.1071/rd14253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 04/04/2015] [Indexed: 02/28/2024] Open
Abstract
The deleted in azoospermia like (Dazl) gene is preferentially expressed in germ cells; however, recent studies indicate that it may have pluripotency-related functions. We generated Dazl-green fluorescent protein (GFP) transgenic mice and assayed the ability of Dazl-driven GFP to mark preimplantation embryo development, fetal, neonatal and adult tissues, and in vitro differentiation from embryonic stem cells (ESCs) to embryoid bodies (EBs) and to primordial germ cell (PGC)-like cells. The Dazl-GFP mice were generated by a two-step ESC-based strategy, which enabled primary and secondary screening of stably transfected clones before embryo injection. During preimplantation embryo stages, GFP was detected from the zygote to blastocyst stage. At Embryonic Day (E) 12.5, GFP was expressed in gonadal ridges and in neonatal gonads of both sexes. In adult mice, GFP expression was found during spermatogenesis from spermatogonia to elongating spermatids and in the cytoplasm of oocytes. However, GFP mRNA was also detected in other tissues harbouring multipotent cells, such as the intestine and bone marrow. Fluorescence was maintained along in vitro Dazl-GFP ESC differentiation to EBs, and in PGC-like cells. In addition to its largely known function in germ cell development, Dazl could have an additional role in pluripotency, supporting these transgenic mice as a valuable tool for the prospective identification of stem cells from several tissues.
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Ye H, Li CJ, Yue HM, Yang XG, Wei QW. Differential expression of fertility genes boule and dazl in Chinese sturgeon (Acipenser sinensis), a basal fish. Cell Tissue Res 2015; 360:413-25. [PMID: 25592848 DOI: 10.1007/s00441-014-2095-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/08/2014] [Indexed: 10/24/2022]
Abstract
The gene family DAZ (deleted in Azoospermia), including boule, dazl and DAZ, performs highly conserved functions in germ cell development and fertility across animal phyla. Differential expression patterns have been demonstrated for the family members in invertebrates and vertebrates including fish. Here, we report the identification of boule and dazl and their expression at both RNA and protein levels in developing and mature gonads of Chinese sturgeon (Acipenser sinensis). Firstly, the isolation of the boule and dazl genes in Chinese sturgeon and the observation of the two genes in coelacanth suggest that dazl originated after the divergence of bony fish from cartilaginous fish but before the emergence of the Actinistia. Quantitative real-time PCR and western blot analyses reveal that boule and dazl RNA and proteins are restricted to the testis and ovary. In situ hybridization and fluorescent immunohistochemistry show that the bisexual mitotic and meiotic germ cell expression of dazl RNA and protein is conserved in vertebrates, while Chinese sturgeon boule RNA and protein exhibit mitotic and meiotic expression in the testis, and also likely display mitotic and meiotic expression in female. Moreover, we directly demonstrate for the first time that sturgeon Balbiani body/mitochondrial cloud disperses in the cytoplasm of early developing oocytes and co-localizes with Dazl to some extent. Finally, urbilaterian boule may also have an ancestral function in oogenesis. Taken together, these results provide useful information on the evolution of DAZ family genes, expression patterns and functions in animal reproduction.
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Abstract
Determination of primordial germ cells (PGCs) is one of the earliest decisions in animal embryogenesis. In many species, PGCs are determined through maternally-inherited germ plasm ribonucleoparticles (RNPs). In zebrafish, these are transmitted during oogenesis as dispersed RNPs, which after fertilization multimerize and become recruited as large aggregates at furrows for the first and second cell cycles. Here, we show that the number of recruited germ plasm RNPs is halved every cell cycle. We also show that germ plasm RNPs are recruited during the third cell cycle, but only transiently. Our data support a mechanism in which systematic local gathering of germ plasm RNPs during cytokinesis and threshold-dependent clearing contribute to forming germ plasm aggregates with the highest RNP number and germ cell-inducing potential.
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Affiliation(s)
- Celeste Eno
- Laboratory of Genetics; University of Wisconsin-Madison; Madison, WI USA
| | - Francisco Pelegri
- Laboratory of Genetics; University of Wisconsin-Madison; Madison, WI USA
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Sekiné K, Furusawa T, Hatakeyama M. The boule gene is essential for spermatogenesis of haploid insect male. Dev Biol 2015; 399:154-163. [PMID: 25592223 DOI: 10.1016/j.ydbio.2014.12.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/18/2014] [Accepted: 12/22/2014] [Indexed: 11/15/2022]
Abstract
boule (bol), a member of the Deleted in Azoospermia (DAZ) gene family plays an important role in meiosis (reductional maturation divisions) in a spermatogenesis-specific manner in animals by regulating translation of the downstream cell division cycle 25 (cdc25) phosphatase mRNA. Orthologues of bol are conserved among animals and found in the genomes of hymenopteran insects, in which the general mode of reproduction is haplodiploidy: female is diploid and male is haploid. In this mode of reproduction, haploid males produce haploid sperm through non-reductional maturation divisions. The question thus arises of whether the bol gene actually functions during spermatogenesis in these haploid males. In this study, we identified two transcriptional isoforms of bol orthologue (Ar bol and Ar bol-2), and one cdc25 orthologue (Ar cdc25) in the hymenopteran sawfly, Athalia rosae. Ar bol was expressed exclusively in the testis when maturation divisions occurred, while Ar bol-2 was expressed ubiquitously. Knockdown of all bol transcripts (both Ar bol and Ar bol-2) resulted in a lack of mature sperm, whereas males with sole knockdown of Ar bol-2 were able to produce a small number of mature sperm. The cell cycle was arrested before maturation divisions in the testis in which all bol transcripts were knocked down, as revealed by flow cytometry. Although no mature sperm was produced, sperm elongation was partially observed when Ar cdc25 alone was knocked down. These results indicate that Ar bol is essential for the entry and progression of maturation divisions and sperm differentiation in haploid males.
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Affiliation(s)
- Kazuki Sekiné
- Division of Insect Sciences, National Institute of Agrobiological Sciences, 1-2, Owashi, Tsukuba, Ibaraki 305-8634, Japan
| | - Tadashi Furusawa
- Division of Animal Sciences, National Institute of Agrobiological Sciences, 2, Ikenodai, Tsukuba, Ibaraki 305-8602, Japan
| | - Masatsugu Hatakeyama
- Division of Insect Sciences, National Institute of Agrobiological Sciences, 1-2, Owashi, Tsukuba, Ibaraki 305-8634, Japan.
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Dwarakanath M, Lim M, Xu H, Hong Y. Differential expression of boule and dazl in adult germ cells of the Asian seabass. Gene 2014; 549:237-42. [PMID: 25084124 DOI: 10.1016/j.gene.2014.07.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 07/06/2014] [Accepted: 07/24/2014] [Indexed: 12/22/2022]
Abstract
Fertility genes boule and dazl constitute the evolutionarily conserved DAZ (Deleted in AZoospermia) family of RNA binding proteins essential for germline development across animal phyla. Here we report the cloning and expression analysis of boule and dazl from the Asian seabass (Lates calcarifer), a marine fish that undergoes sequential male-to-female sex reversal. Molecular cloning and sequence comparison led to the identification of boule and dazl cDNAs. RT-PCR analysis showed that both boule and dazl RNAs were restricted to the gonads among adult organs examined. Chromogenic in situ hybridization revealed germ cell-specific expression for both boule and dazl in female and male adults. Importantly, distinct differences were found between boule and dazl in terms of temporospatial expression and subcellular distribution. The boule RNA was abundant in late gametogenic cells except sperm. Interestingly, dazl expression increases in early oocytes and concentrates in a perinuclear speckle that appears to develop ultimately into the Balbiani body in advanced oocytes. The dazl RNA was found to be abundant in spermatocytes but hardly detectable in sperm. These data demonstrate that boule and dazl are germ cell markers in the adult Asian seabass, and that bisexual germline-specific expression has been conserved for boule and dazl in fish.
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Affiliation(s)
- Manali Dwarakanath
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore
| | - Menghuat Lim
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore
| | - Hongyan Xu
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore.
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Wang K, Zhang H, Hu Q, Shao C, Chen S. Expression and purification of half-smooth tongue sole (Cynoglossus semilaevis) CSDAZL protein. Protein Expr Purif 2014; 102:8-12. [PMID: 25064428 DOI: 10.1016/j.pep.2014.07.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 07/14/2014] [Accepted: 07/15/2014] [Indexed: 11/28/2022]
Abstract
The csdazl gene is a sex related gene of half-smooth tongue sole (Cynoglossus semilaevis). Our research group have cloned full length cDNA of csdazl, and studied its expression pattern. To get the further information of csdazl, we constructed a prokaryotic expression plasmid, pET-32a-CSDAZL, expressed in Escherichia coli BL21 and purified the fusion protein by His Trap. In order to detect the biological activity of the fusion protein, we injected the protein with liposome into fish, and detected other sex-related genes' mRNA expression. The results showed that the expression levels of half-smooth tongue sole female-related genes Cyp19a and Foxl2 significantly decreased between 6 and 24 h; however, both genes' expressions returned to their normal levels 72 h after injection, indicating that recombinant CSDAZL protein could down-regulated the expression of female-related genes, Foxl2 and Cyp19a genes, implying that the fusion protein has biological activity and csdazl plays a role in sex differentiation by regulating sex related genes' expression.
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Affiliation(s)
- Kailin Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China
| | - Hong Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Qiaomu Hu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Changwei Shao
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China
| | - Songlin Chen
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China.
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37
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Ge X, Grotjahn D, Welch E, Lyman-Gingerich J, Holguin C, Dimitrova E, Abrams EW, Gupta T, Marlow FL, Yabe T, Adler A, Mullins MC, Pelegri F. Hecate/Grip2a acts to reorganize the cytoskeleton in the symmetry-breaking event of embryonic axis induction. PLoS Genet 2014; 10:e1004422. [PMID: 24967891 PMCID: PMC4072529 DOI: 10.1371/journal.pgen.1004422] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 04/20/2014] [Indexed: 11/18/2022] Open
Abstract
Maternal homozygosity for three independent mutant hecate alleles results in embryos with reduced expression of dorsal organizer genes and defects in the formation of dorsoanterior structures. A positional cloning approach identified all hecate mutations as stop codons affecting the same gene, revealing that hecate encodes the Glutamate receptor interacting protein 2a (Grip2a), a protein containing multiple PDZ domains known to interact with membrane-associated factors including components of the Wnt signaling pathway. We find that grip2a mRNA is localized to the vegetal pole of the oocyte and early embryo, and that during egg activation this mRNA shifts to an off-center vegetal position corresponding to the previously proposed teleost cortical rotation. hecate mutants show defects in the alignment and bundling of microtubules at the vegetal cortex, which result in defects in the asymmetric movement of wnt8a mRNA as well as anchoring of the kinesin-associated cargo adaptor Syntabulin. We also find that, although short-range shifts in vegetal signals are affected in hecate mutant embryos, these mutants exhibit normal long-range, animally directed translocation of cortically injected dorsal beads that occurs in lateral regions of the yolk cortex. Furthermore, we show that such animally-directed movement along the lateral cortex is not restricted to a single arc corresponding to the prospective dorsal region, but occur in multiple meridional arcs even in opposite regions of the embryo. Together, our results reveal a role for Grip2a function in the reorganization and bundling of microtubules at the vegetal cortex to mediate a symmetry-breaking short-range shift corresponding to the teleost cortical rotation. The slight asymmetry achieved by this directed process is subsequently amplified by a general cortical animally-directed transport mechanism that is neither dependent on hecate function nor restricted to the prospective dorsal axis. One of the earliest and most crucial events in animal development is the establishment of the embryonic dorsal axis. In amphibians and fish, this event depends on the transport of so-called “dorsal determinants” from one region of the egg, at the pole opposite from the site where the oocyte nucleus lies, towards the site of axis induction. There, the dorsal determinant activates the Wnt signaling pathway, which in turn triggers dorsal gene expression. Dorsal determinant transport is mediated by the reorganization of a cellular network composed of microtubules. We determine that hecate, a zebrafish gene active during egg formation that is essential for embryonic axis induction, is required for an early step in this microtubule reorganization. We find that hecate corresponds to glutamate receptor interacting protein 2a, which participates in other animal systems in Wnt-based pathways. We also show that the microtubule reorganization dependent on hecate results in a subtle symmetry-breaking event that subsequently becomes amplified by a more general transport process independent of hecate function. Our data reveal new links between glutamate receptor interacting protein 2a, Wnt signaling and axis induction, and highlights basic mechanisms by which small changes early in development translate into global changes in the embryo.
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Affiliation(s)
- Xiaoyan Ge
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Danielle Grotjahn
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Elaine Welch
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Jamie Lyman-Gingerich
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Christiana Holguin
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Eva Dimitrova
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Elliot W. Abrams
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tripti Gupta
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Florence L. Marlow
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Taijiro Yabe
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Anna Adler
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
| | - Mary C. Mullins
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Francisco Pelegri
- Laboratory of Genetics, University of Wisconsin – Madison, Madison, Wisconsin, United States of America
- * E-mail:
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Abstract
It is becoming recognized that the extraembryonic domains of developing vertebrates, that is, those that make no cellular contribution to the embryo proper, act as important signaling centers that induce and pattern the germ layers and help establish the key embryonic axes. In the embryos of teleost fish, in particular, significant progress has been made in understanding how signaling activity in extraembryonic domains, such as the enveloping layer, the yolk syncytial layer, and the yolk cell, might help regulate development via a combination of inductive interactions, cellular dynamics, and localized gene expression. Ca(2+) signaling in a variety of forms that include propagating waves and standing gradients is a feature found in all three teleostean extraembryonic domains. This leads us to propose that in addition to their other well-characterized signaling activities, extraembryonic domains are well suited (due to their relative stability and continuity) to act as Ca(2+) signaling centers and conduits.
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Affiliation(s)
- Sarah E Webb
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
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Heim AE, Hartung O, Rothhämel S, Ferreira E, Jenny A, Marlow FL. Oocyte polarity requires a Bucky ball-dependent feedback amplification loop. Development 2014; 141:842-54. [PMID: 24496621 DOI: 10.1242/dev.090449] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In vertebrates, the first asymmetries are established along the animal-vegetal axis during oogenesis, but the underlying molecular mechanisms are poorly understood. Bucky ball (Buc) was identified in zebrafish as a novel vertebrate-specific regulator of oocyte polarity, acting through unknown molecular interactions. Here we show that endogenous Buc protein localizes to the Balbiani body, a conserved, asymmetric structure in oocytes that requires Buc for its formation. Asymmetric distribution of Buc in oocytes precedes Balbiani body formation, defining Buc as the earliest marker of oocyte polarity in zebrafish. Through a transgenic strategy, we determined that excess Buc disrupts polarity and results in supernumerary Balbiani bodies in a 3'UTR-dependent manner, and we identified roles for the buc introns in regulating Buc activity. Analyses of mosaic ovaries indicate that oocyte pattern determines the number of animal pole-specific micropylar cells that are associated with an egg via a close-range signal or direct cell contact. We demonstrate interactions between Buc protein and buc mRNA with two conserved RNA-binding proteins (RNAbps) that are localized to the Balbiani body: RNA binding protein with multiple splice isoforms 2 (Rbpms2) and Deleted in azoospermia-like (Dazl). Buc protein and buc mRNA interact with Rbpms2; buc and dazl mRNAs interact with Dazl protein. Cumulatively, these studies indicate that oocyte polarization depends on tight regulation of buc: Buc establishes oocyte polarity through interactions with RNAbps, initiating a feedback amplification mechanism in which Buc protein recruits RNAbps that in turn recruit buc and other RNAs to the Balbiani body.
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Affiliation(s)
- Amanda E Heim
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Smorag L, Xu X, Engel W, Pantakani DVK. The roles of DAZL in RNA biology and development. Wiley Interdiscip Rev RNA 2014; 5:527-35. [PMID: 24715697 DOI: 10.1002/wrna.1228] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/17/2014] [Accepted: 02/18/2014] [Indexed: 01/20/2023]
Abstract
RNA-binding proteins play an important role in the regulation of gene expression by modulating translation and localization of specific messenger RNAs (mRNAs) during early development and gametogenesis. The DAZ (Deleted in Azoospermia) family of proteins, which includes DAZ, DAZL, and BOULE, are germ cell-specific RNA-binding proteins that are implicated in translational regulation of several transcripts. Of particular importance is DAZL, which is present in vertebrates and arose from the duplication of the ancestral BOULE during evolution. Identification of DAZL target mRNAs and characterization of the RNA-binding sequence through in vitro binding assays and crystallographic studies revealed that DAZL binds to GUU triplets in the 3' untranslated region of target mRNAs. Although there is compelling evidence for the role of DAZL in translation stimulation of target mRNAs, recent studies indicate that DAZL can also function in translational repression and transport of specific mRNAs. Furthermore, apart from the well-characterized function of DAZL in gametogenesis, recent data suggest its role in early embryonic development and differentiation of pluripotent stem cells toward functional gametes. In light of the mounting evidence for the role of DAZL in various cellular and developmental processes, we summarize the currently characterized biological functions of DAZL in RNA biology and development.
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Affiliation(s)
- Lukasz Smorag
- Institute of Human Genetics, University of Goettingen, Goettingen, Germany
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41
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Bhat N, Hong Y. Cloning and expression of boule and dazl in the Nile tilapia (Oreochromis niloticus). Gene 2014; 540:140-5. [PMID: 24607036 DOI: 10.1016/j.gene.2014.02.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/10/2014] [Accepted: 02/28/2014] [Indexed: 11/26/2022]
Abstract
The Deleted in Azoospermia (DAZ) family of RNA binding proteins consists of highly conserved genes boule, daz and daz-like (dazl) essential for germ cell development. boule is known for its unisexual meiotic expression in invertebrates and mammals, but meiotic-specific female expression plus meiosis-preferential male expression in trout, and meiosis-preferential bisexual expression in medaka. dazl shows highly conserved bisexual expression throughout gametogenesis in diverse species. Here we report the cloning and expression of boule and dazl in the Nile tilapia (Oreochromis niloticus), an important aquaculture fish. Molecular cloning and sequence analysis led to the identification of tilapia boule and dazl cDNAs. The predicted partial Boule contains a conserved RRM motif and Dazl has the C-terminal sequence. On a phylogenetic tree, tilapia Boule and Dazl are in separate clades of Boule and Dazl homologs from other species, indicating their divergence during early vertebrate evolution. By RT-PCR analysis, boule and dazl showed bisexual gonad-specific expression. By in situ hybridization analysis, both boule and dazl RNAs were restricted to female and male germ cells of adult gonads but absent in gonadal soma. In the ovary, boule and dazl RNAs were abundant in oocytes. In the testis, boule and dazl RNAs were prominent in meiotic spermatocytes but barely detectable in meiotic products. These data show that boule and dazl are expressed bisexually in germ cells and provide useful markers to study gametogenesis in the adult tilapia.
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Affiliation(s)
- Narayani Bhat
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore.
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Saito T, Pšenička M, Goto R, Adachi S, Inoue K, Arai K, Yamaha E. The origin and migration of primordial germ cells in sturgeons. PLoS One 2014; 9:e86861. [PMID: 24505272 PMCID: PMC3914811 DOI: 10.1371/journal.pone.0086861] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/11/2013] [Indexed: 11/19/2022] Open
Abstract
Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts.
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Affiliation(s)
- Taiju Saito
- Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Japan ; Laboratory of Aquaculture Genetics & Genomics, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan ; Laboratory of Reproductive Physiology, Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodňany, Czech Republic
| | - Martin Pšenička
- Laboratory of Reproductive Physiology, Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Vodňany, Czech Republic
| | - Rie Goto
- Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Japan
| | - Shinji Adachi
- Laboratory of Aquaculture Biology, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Kunio Inoue
- Department of Biology, Faculty of Science, Kobe University, Kobe, Japan
| | - Katsutoshi Arai
- Laboratory of Aquaculture Genetics & Genomics, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Japan
| | - Etsuro Yamaha
- Nanae Fresh Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Nanae, Japan
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Li M, Liu C, Zhu H, Sun J, Yu M, Niu Z, Liu W, Peng S, Hua J. Expression pattern of Boule in dairy goat testis and its function in promoting the meiosis in male germline stem cells (mGSCs). J Cell Biochem 2013; 114:294-302. [PMID: 22930651 DOI: 10.1002/jcb.24368] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2012] [Accepted: 08/13/2012] [Indexed: 11/06/2022]
Abstract
Boule is a conserved gene in meiosis, which encodes RNA binding protein required for spermatocyte meiosis. Deletion of Boule was found to block meiosis in spermatogenesis, which contributes to infertility. Up to date, the expression and function of Boule in the goat testis are not known. The objectives of this study were to investigate the expression pattern of Boule in dairy goat testis and their function in male germline stem cells (mGSCs). The results first revealed that the expression level of Boule in adult testes was significantly higher than younger and immature goats, and azoospermia and male intersex testis. Over-expression of Boule promoted the expression of meiosis-related genes in dairy goat mGSCs. The expression of Stra8 was up-regulated by over-expression of Boule analyzed by Western blotting and Luciferase reporter assay. While, Cdc25a, the downstream regulator of Boule, was found not to affect the expression of Stra8, and our data illustrated that Cdc25a did not regulate meiosis via Stra8. The expression of Stra8 and Boule was up-regulated by RA induction. Taken together, results suggest the Boule plays an important role in dairy goat spermatogenesis and that over-expression of Boule may promote spermatogenesis and meiosis in dairy goat.
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Affiliation(s)
- Mingzhao Li
- College of Veterinary Medicine, Shaanxi Center of Stem Cells Engineering & Technology, Key Lab for Animal Biotechnology of Agriculture Ministry of China, Northwest A&F University, Yangling, Shaanxi 712100, China
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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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Gao M, Arkov AL. Next generation organelles: structure and role of germ granules in the germline. Mol Reprod Dev 2012; 80:610-23. [PMID: 23011946 DOI: 10.1002/mrd.22115] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/14/2012] [Indexed: 12/20/2022]
Abstract
Germ cells belong to a unique class of stem cells that gives rise to eggs and sperm, and ultimately to an entire organism after gamete fusion. In many organisms, germ cells contain electron-dense structures that are also known as nuage or germ granules. Although germ granules were discovered more than 100 years ago, their composition, structure, assembly, and function are not fully understood. Germ granules contain non-coding RNAs, mRNAs, and proteins required for germline development. Here we review recent studies that highlight the importance of several protein families in germ granule assembly and function, including germ granule inducers, which initiate the granule formation, and downstream components, such as RNA helicases and Tudor domain-Piwi protein-piRNA complexes. Assembly of these components into one granule is likely to result in a highly efficient molecular machine that ensures translational control and protects germline DNA from mutations caused by mobile genetic elements. Furthermore, recent studies have shown that different somatic cells, including stem cells and neurons, produce germ granule components that play a crucial role in stem cell maintenance and memory formation, indicating a much more diverse functional repertoire for these organelles than previously thought.
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Affiliation(s)
- Ming Gao
- Department of Biological Sciences, Murray State University, Murray, Kentucky 42071, USA
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Kuales G, De Mulder K, Glashauser J, Salvenmoser W, Takashima S, Hartenstein V, Berezikov E, Salzburger W, Ladurner P. Boule-like genes regulate male and female gametogenesis in the flatworm Macrostomum lignano. Dev Biol 2011; 357:117-32. [PMID: 21740899 PMCID: PMC3158854 DOI: 10.1016/j.ydbio.2011.06.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 06/17/2011] [Accepted: 06/20/2011] [Indexed: 11/22/2022]
Abstract
Members of the DAZ (Deleted in AZoospermia) gene family are important players in the process of gametogenesis and their dysregulation accounts for 10% of human male infertility. Boule, the ancestor of the family, is mainly involved in male meiosis in most organisms. With the exception of Drosophila and C. elegans, nothing is known on the function of boule in non-vertebrate animals. In the present study, we report on three boule orthologues in the flatworm Macrostomum lignano. We demonstrate that macbol1 and macbol2 are expressed in testes whilst macbol3 is expressed in ovaries and developing eggs. Macbol1 RNAi blocked spermatocyte differentiation whereas macbol2 showed no effect upon RNAi treatment. Macbol3 RNAi resulted in aberrant egg maturation and led to female sterility. We further demonstrated the evolutionary functional conservation of macbol1 by introducing this gene into Drosophila bol(1) mutants. Macbol1 was able to rescue the progression of fly meiotic divisions. In summary, our findings provide evidence for an involvement of boule genes in male and female gamete development in one organism. Furthermore, boule gene function is shown here for the first time in a lophotrochozoan. Our results point to a more diverse functional assignment of boule genes. Therefore, a better understanding of boule function in flatworms can help to elucidate the molecular mechanisms of and concomitant infertility in higher organisms including humans.
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Affiliation(s)
- Georg Kuales
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25 A-6020 Innsbruck, Austria
| | - Katrien De Mulder
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25 A-6020 Innsbruck, Austria
- Hubrecht Institute and University medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Jade Glashauser
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25 A-6020 Innsbruck, Austria
| | - Willi Salvenmoser
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25 A-6020 Innsbruck, Austria
| | - Shigeo Takashima
- University of California Los Angeles, Department of Molecular, Cell and Developmental Biology, 621 Charles E. Young Drive, East Boyer Hall 559, CA 90095-1606 California, USA
| | - Volker Hartenstein
- University of California Los Angeles, Department of Molecular, Cell and Developmental Biology, 621 Charles E. Young Drive, East Boyer Hall 559, CA 90095-1606 California, USA
| | - Eugene Berezikov
- Hubrecht Institute and University medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | - Walter Salzburger
- University of Basel, Zoological Institute, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Peter Ladurner
- University of Innsbruck, Institute of Zoology and CMBI, Technikerstrasse 25 A-6020 Innsbruck, Austria
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Abstract
Human infertility is common and frequently linked to poor germ cell development. Yet, human germ cell development is poorly understood, at least in part due to the inaccessibility of germ cells to study especially during fetal development. Here, we explored the function of a highly conserved family of genes, the NANOS genes, in the differentiation of human germ cells from human embryonic stem cells. We observed that NANOS-1, -2 and -3 mRNAs and proteins were expressed in human gonads. We also noted that NANOS3 was expressed in germ cells throughout spermatogenesis and oogenesis and thus, focused further efforts on this family member. NANOS3 expression was highest in human germ cell nuclei where the protein co-localized with chromosomal DNA during mitosis/meiosis. Reduced expression of NANOS3 (via morpholinos or short hairpin RNA) resulted in a reduction in germ cell numbers and decreased expression of germ cell-intrinsic genes required for the maintenance of pluripotency and meiotic initiation and progression. These data provide the first direct experimental evidence that NANOS3 functions in human germ cell development; indeed, NANOS3 is now one of just two genes that has been directly shown to function in germ cell development across diverse species from flies, worms, frogs and mice to humans [the other is BOULE, a member of the Deleted in Azoospermia (DAZ) gene family]. Findings may contribute to our understanding of the basic biology of human germ cell development and may provide clinical insights regarding infertility.
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Affiliation(s)
| | - Renee A. Reijo Pera
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford University, Palo Alto, CA 94305, USA
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Li M, Shen Q, Xu H, Wong FM, Cui J, Li Z, Hong N, Wang L, Zhao H, Ma B, Hong Y. Differential conservation and divergence of fertility genes boule and dazl in the rainbow trout. PLoS One 2011; 6:e15910. [PMID: 21253610 PMCID: PMC3017096 DOI: 10.1371/journal.pone.0015910] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 11/29/2010] [Indexed: 12/01/2022] Open
Abstract
Background The genes boule and dazl are members of the DAZ (Deleted in Azoospermia) family encoding RNA binding proteins essential for germ cell development. Although dazl exhibits bisexual expression in mitotic and meiotic germ cells in diverse animals, boule shows unisexual meiotic expression in invertebrates and mammals but a bisexual mitotic and meiotic expression in medaka. How boule and dazl have evolved different expression patterns in diverse organisms has remained unknown. Methodology and Principal Findings Here we chose the fish rainbow trout (Oncorhynchus mykiss) as a second lower vertebrate model to investigate the expression of boule and dazl. By molecular cloning and sequence comparison, we identified cDNAs encoding the trout Boule and Dazl proteins, which have a conserved RNA-recognition motif and a maximal similarity to their homologs. By RT-PCR analysis, adult RNA expression of trout boule and dazl is restricted to the gonads of both sexes. By chromogenic and two-color fluorescence in situ hybridization, we revealed bisexual and germline-specific expression of boule and dazl. We found that dazl displays conserved expression throughout gametogenesis and concentrates in the Balbinani's body of early oocytes and the chromatoid body of sperm. Surprisingly, boule exhibits mitotic and meiotic expression in the male but meiosis-specific expression in the female. Conclusions Our data underscores differential conservation and divergence of DAZ family genes during vertebrate evolution. We propose a model in which the diversity of boule expression in sex and stage specificity might have resulted from selective loss or gain of its expression in one sex and mitotic germ cells.
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Affiliation(s)
- Mingyou Li
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Qian Shen
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Hongyan Xu
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Foong Mei Wong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jianzhou Cui
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Zhendong Li
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Ni Hong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Li Wang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Haobin Zhao
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Bo Ma
- Heilongjiang Fisheries Research Institute, Ha'erbin City, China
| | - Yunhan Hong
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Jingzhou, China
- * E-mail:
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Abstract
The DAZ family of genes are important fertility factors in animals, including humans. The family consists of Y-linked DAZ, and autosomal homologs Boule and Dazl. All three genes encode RNA-binding proteins that are nearly exclusively expressed in germ cells. The DAZ family is highly conserved, with ancestral Boule present in sea anemones through humans, Dazl conserved among vertebrates, and DAZ present only in higher primates. Here we review studies on DAZ family genes from multiple organisms, and summarize the common features of each DAZ gene and their roles during spermatogenesis in animals. DAZ family proteins are thought to activate the translation of RNA targets, but recent work has uncovered additional functions. Boule, Dazl, and DAZ likely function through similar mechanisms, and we present known functions of the DAZ family in spermatogenesis, and discuss possible mechanisms in addition to translation activation.
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Affiliation(s)
- Michael J W Vangompel
- Department of Obstetrics and Gynecology; Division of Reproductive Biology Research and Center for Genetic Medicine; Northwestern University; Chicago, IL USA
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