1
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Pieplow C, Wessel G. Functional annotation of a hugely expanded nanos repertoire in Lytechinus variegatus, the green sea urchin. Mol Reprod Dev 2023; 90:310-322. [PMID: 37039283 PMCID: PMC10225336 DOI: 10.1002/mrd.23684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/17/2023] [Accepted: 03/18/2023] [Indexed: 04/12/2023]
Abstract
Nanos genes encode essential RNA-binding proteins involved in germline determination and germline stem cell maintenance. When examining diverse classes of echinoderms, typically three, sometimes four, nanos genes are present. In this analysis, we identify and annotate nine nanos orthologs in the green sea urchin, Lytechinus variegatus (Lv). All nine genes are transcribed and grouped into three distinct classes. Class one includes the germline Nanos, with one member: Nanos2. Class two includes Nanos3-like genes, with significant sequence similarity to Nanos3 in the purple sea urchin, Strongylocentrotus purpuratus (Sp), but with wildly variable expression patterns. The third class includes several previously undescribed nanos zinc-finger genes that may be the result of duplications of Nanos2. All nine nanos transcripts occupy unique genomic loci and are expressed with unique temporal profiles during development. Importantly, here we describe and characterize the unique genomic location, conservation, and phylogeny of the Lv ortholog of the well-studied Sp Nanos2. However, in addition to the conserved germline functioning Nanos2, the green sea urchin appears to be an outlier in the echinoderm phyla with eight additional nanos genes. We hypothesize that this expansion of nanos gene members may be the result of a previously uncharacterized L1-class transposon encoded on the opposite strand of a nanos2 pseudogene present on chromosome 12 in this species. The expansion of nanos genes described here represents intriguing insights into germline specification and nanos evolution in this species of sea urchin.
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Affiliation(s)
- Cosmo Pieplow
- MCB Department, Division of Biomedicine, Brown University, Providence RI 02912
| | - Gary Wessel
- MCB Department, Division of Biomedicine, Brown University, Providence RI 02912
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2
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Oulhen N, Morita S, Warner JF, Wessel G. CRISPR/Cas9 knockin methodology for the sea urchin embryo. Mol Reprod Dev 2023; 90:69-72. [PMID: 36719060 PMCID: PMC9979971 DOI: 10.1002/mrd.23672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/05/2023] [Accepted: 01/16/2023] [Indexed: 02/01/2023]
Affiliation(s)
- Nathalie Oulhen
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Shumpei Morita
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
- Present Address: Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Aomori, Aomori, 039-3501, Japan
| | - Jacob F. Warner
- Department of Biology and Marine Biology. University of North Carolina Wilmington, Wilmington, NC 28403
| | - Gary Wessel
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
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3
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Post-transcriptional regulation of factors important for the germ line. Curr Top Dev Biol 2022; 146:49-78. [PMID: 35152986 DOI: 10.1016/bs.ctdb.2021.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Echinoderms are a major model system for many general aspects of biology, including mechanisms of gene regulation. Analysis of transcriptional regulation (Gene regulatory networks, direct DNA-binding of proteins to specific cis-elements, and transgenesis) has contributed to our understanding of how an embryo works. This chapter looks at post-transcriptional gene regulation in the context of how the primordial germ cells are formed, and how the factors essential for this process are regulated. Important in echinoderms, as in many embryos, is that key steps of fate determination are made post-transcriptionally. This chapter highlights these steps uncovered in sea urchins and sea stars, and links them to a general theme of how the germ line may regulate its fate differently than many of the embryo's somatic cell lineages.
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4
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Wessel GM, Morita S, Oulhen N. Somatic cell conversion to a germ cell lineage: A violation or a revelation? JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2021; 336:666-679. [PMID: 32445519 PMCID: PMC7680723 DOI: 10.1002/jez.b.22952] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/29/2022]
Abstract
The germline is unique and immortal (or at least its genome is). It is able to perform unique jobs (meiosis) and is selected for genetic changes. Part of being this special also means that entry into the germline club is restricted and cells of the soma are always left out. However, the recent evidence from multiple animals now suggests that somatic cells may join the club and become germline cells in an animal when the original germline is removed. This "violation" may have garnered acceptance by the observation that iPScells, originating experimentally from somatic cells of an adult, can form reproductively successful eggs and sperm, all in vitro. Each of the genes and their functions used to induce pluripotentiality are found normally in the cell and the in vitro conditions to direct germline commitment replicate conditions in vivo. Here, we discuss evidence from three different animals: an ascidian, a segmented worm, and a sea urchin; and that the cells of a somatic cell lineage can convert into the germline in vivo. We discuss the consequences of such transitions and provide thoughts as how this process may have equal precision to the original germline formation of an embryo.
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Affiliation(s)
- Gary M. Wessel
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
| | - Shumpei Morita
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
| | - Nathalie Oulhen
- Department of Molecular and Cellular Biology, Brown University, Providence RI 02912 USA
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5
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Pieplow A, Dastaw M, Sakuma T, Sakamoto N, Yamamoto T, Yajima M, Oulhen N, Wessel GM. CRISPR-Cas9 editing of non-coding genomic loci as a means of controlling gene expression in the sea urchin. Dev Biol 2021; 472:85-97. [PMID: 33482173 PMCID: PMC7956150 DOI: 10.1016/j.ydbio.2021.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 01/11/2021] [Accepted: 01/11/2021] [Indexed: 11/28/2022]
Abstract
We seek to manipulate gene function here through CRISPR-Cas9 editing of cis-regulatory sequences, rather than the more typical mutation of coding regions. This approach would minimize secondary effects of cellular responses to nonsense mediated decay pathways or to mutant protein products by premature stops. This strategy also allows for reducing gene activity in cases where a complete gene knockout would result in lethality, and it can be applied to the rapid identification of key regulatory sites essential for gene expression. We tested this strategy here with genes of known function as a proof of concept, and then applied it to examine the upstream genomic region of the germline gene Nanos2 in the sea urchin, Strongylocentrotus purpuratus. We first used CRISPR-Cas9 to target established genomic cis-regulatory regions of the skeletogenic cell transcription factor, Alx1, and the TGF-β signaling ligand, Nodal, which produce obvious developmental defects when altered in sea urchin embryos. Importantly, mutation of cis-activator sites (Alx1) and cis-repressor sites (Nodal) result in the predicted decreased and increased transcriptional output, respectively. Upon identification of efficient gRNAs by genomic mutations, we then used the same validated gRNAs to target a deadCas9-VP64 transcriptional activator to increase Nodal transcription directly. Finally, we paired these new methodologies with a more traditional, GFP reporter construct approach to further our understanding of the transcriptional regulation of Nanos2, a key gene required for germ cell identity in S. purpuratus. With a series of reporter assays, upstream Cas9-promoter targeted mutagenesis, coupled with qPCR and in situ RNA hybridization, we concluded that the promoter of Nanos2 drives strong mRNA expression in the sea urchin embryo, indicating that its primordial germ cell (PGC)-specific restriction may rely instead on post-transcriptional regulation. Overall, we present a proof-of-principle tool-kit of Cas9-mediated manipulations of promoter regions that should be applicable in most cells and embryos for which CRISPR-Cas9 is employed.
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Affiliation(s)
- Alice Pieplow
- Department of Molecular Biology, Cellular Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Meseret Dastaw
- Ethiopian Biotechnology Institute, Addis Ababa University, NBH1, 4killo King George VI St, Addis Ababa, Ethiopia
| | - Tetsushi Sakuma
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Naoaki Sakamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, 739-8526, Japan
| | - Mamiko Yajima
- Department of Molecular Biology, Cellular Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Nathalie Oulhen
- Department of Molecular Biology, Cellular Biology and Biochemistry, Brown University, Providence, RI, 02912, USA
| | - Gary M Wessel
- Department of Molecular Biology, Cellular Biology and Biochemistry, Brown University, Providence, RI, 02912, USA.
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6
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D'Orazio FM, Balwierz PJ, González AJ, Guo Y, Hernández-Rodríguez B, Wheatley L, Jasiulewicz A, Hadzhiev Y, Vaquerizas JM, Cairns B, Lenhard B, Müller F. Germ cell differentiation requires Tdrd7-dependent chromatin and transcriptome reprogramming marked by germ plasm relocalization. Dev Cell 2021; 56:641-656.e5. [PMID: 33651978 PMCID: PMC7957325 DOI: 10.1016/j.devcel.2021.02.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 10/25/2020] [Accepted: 02/03/2021] [Indexed: 02/09/2023]
Abstract
In many animal models, primordial germ cell (PGC) development depends on maternally deposited germ plasm, which prevents somatic cell fate. Here, we show that PGCs respond to regulatory information from the germ plasm in two distinct phases using two distinct mechanisms in zebrafish. We demonstrate that PGCs commence zygotic genome activation together with the somatic blastocysts with no demonstrable differences in transcriptional and chromatin opening. Unexpectedly, both PGC and somatic blastocysts activate germ-cell-specific genes, which are only stabilized in PGCs by cytoplasmic germ plasm determinants. Disaggregated perinuclear relocalization of germ plasm during PGC migration is regulated by the germ plasm determinant Tdrd7 and is coupled to dramatic divergence between PGC and somatic transcriptomes. This transcriptional divergence relies on PGC-specific cis-regulatory elements characterized by promoter-proximal distribution. We show that Tdrd7-dependent reconfiguration of chromatin accessibility is required for elaboration of PGC fate but not for PGC migration. No evidence for transcriptional activation delay in zebrafish PGCs Germ-plasm-associated post-transcriptional divergence during ZGA Epigenetic reprogramming marks onset of PGC migration Epigenetic reprogramming in PGCs relies on Tdrd7, coupled to germ plasm relocalization
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Affiliation(s)
- Fabio M D'Orazio
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK; MRC London Institute of Medical Sciences and Faculty of Medicine, Imperial College, London, UK; Institute of Clinical Sciences, Faculty of Medicine, Imperial College, London, UK
| | - Piotr J Balwierz
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK; MRC London Institute of Medical Sciences and Faculty of Medicine, Imperial College, London, UK; Institute of Clinical Sciences, Faculty of Medicine, Imperial College, London, UK
| | - Ada Jimenez González
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Yixuan Guo
- Department of Oncological Sciences and Huntsman Cancer Institute, Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT, USA
| | | | - Lucy Wheatley
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Aleksandra Jasiulewicz
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Yavor Hadzhiev
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Juan M Vaquerizas
- MRC London Institute of Medical Sciences and Faculty of Medicine, Imperial College, London, UK; Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, Muenster, Germany
| | - Bradley Cairns
- Department of Oncological Sciences and Huntsman Cancer Institute, Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Boris Lenhard
- MRC London Institute of Medical Sciences and Faculty of Medicine, Imperial College, London, UK; Institute of Clinical Sciences, Faculty of Medicine, Imperial College, London, UK.
| | - Ferenc Müller
- Institute of Cancer and Genomics Sciences, Birmingham Centre for Genome Biology, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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7
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Oulhen N, Swartz SZ, Wang L, Wikramanayake A, Wessel GM. Distinct transcriptional regulation of Nanos2 in the germ line and soma by the Wnt and delta/notch pathways. Dev Biol 2019; 452:34-42. [PMID: 31075220 PMCID: PMC6848975 DOI: 10.1016/j.ydbio.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/19/2019] [Accepted: 04/21/2019] [Indexed: 12/23/2022]
Abstract
Specification of the primordial germ cells (PGCs) is essential for sexually reproducing animals. Although the mechanisms of PGC specification are diverse between organisms, the RNA binding protein Nanos is consistently required in the germ line in all species tested. How Nanos is selectively expressed in the germ line, however, remains largely elusive. We report that in sea urchin embryos, the early expression of Nanos2 in the PGCs requires the maternal Wnt pathway. During gastrulation, however, Nanos2 expression expands into adjacent somatic mesodermal cells and this secondary Nanos expression instead requires Delta/Notch signaling through the forkhead family member FoxY. Each of these transcriptional regulators were tested by chromatin immunoprecipitation analysis and found to directly interact with a DNA locus upstream of Nanos2. Given the conserved importance of Nanos in germ line specification, and the derived character of the micromeres and small micromeres in the sea urchin, we propose that the ancestral mechanism of Nanos2 expression in echinoderms was by induction in mesodermal cells during gastrulation.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, RI, 02912, USA
| | - S Zachary Swartz
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA, 02142, USA
| | - Lingyu Wang
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | | | - Gary M Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, 185 Meeting Street, Providence, RI, 02912, USA.
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8
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Vastenhouw NL, Cao WX, Lipshitz HD. The maternal-to-zygotic transition revisited. Development 2019; 146:146/11/dev161471. [PMID: 31189646 DOI: 10.1242/dev.161471] [Citation(s) in RCA: 229] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The development of animal embryos is initially directed by maternal gene products. Then, during the maternal-to-zygotic transition (MZT), developmental control is handed to the zygotic genome. Extensive research in both vertebrate and invertebrate model organisms has revealed that the MZT can be subdivided into two phases, during which very different modes of gene regulation are implemented: initially, regulation is exclusively post-transcriptional and post-translational, following which gradual activation of the zygotic genome leads to predominance of transcriptional regulation. These changes in the gene expression program of embryos are precisely controlled and highly interconnected. Here, we review current understanding of the mechanisms that underlie handover of developmental control during the MZT.
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Affiliation(s)
- Nadine L Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Wen Xi Cao
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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9
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Zhang J, Han X, Wang J, Liu BZ, Wei JL, Zhang WJ, Sun ZH, Chang YQ. Molecular Cloning and Sexually Dimorphic Expression Analysis of nanos2 in the Sea Urchin, Mesocentrotus nudus. Int J Mol Sci 2019; 20:ijms20112705. [PMID: 31159444 PMCID: PMC6600436 DOI: 10.3390/ijms20112705] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 05/26/2019] [Accepted: 05/30/2019] [Indexed: 12/15/2022] Open
Abstract
Sea urchin (Mesocentrotus nudus) is an economically important mariculture species in China and the gonads are the solely edible parts to human. The molecular mechanisms of gonad development have attracted increasing attention in recent years. Although the nanos2 gene has been identified as a germ cell marker in several invertebrates, little is known about nanos2 in adult sea urchins. Hereinto, we report the characterization of Mnnano2, an M. nudus nanos2 homology gene. Mnnanos2 is a maternal factor and can be detected continuously during embryogenesis and early ontogeny. Real-time quantitative PCR (RT-qPCR) and section in situ hybridization (ISH) analysis revealed a dynamic and sexually dimorphic expression pattern of Mnnano2 in the gonads. Its expression reached the maximal level at Stage 2 along with the gonad development in both ovary and testis. In the ovary, Mnnanos2 is specifically expressed in germ cells. In contrast, Mnnanos2 is expressed in both nutritive phagocytes (NP) cells and male germ cells in testis. Moreover, knocking down of Mnnanos2 by means of RNA interference (RNAi) reduced nanos2 and boule expression but conversely increased the expression of foxl2. Therefore, our data suggest that Mnnanos2 may serve as a female germ cell marker during gametogenesis and provide chances to uncover its function in adult sea urchin.
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Affiliation(s)
- Jian Zhang
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Xiao Han
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Jin Wang
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Bing-Zheng Liu
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Jin-Liang Wei
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Wei-Jie Zhang
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Zhi-Hui Sun
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
| | - Ya-Qing Chang
- Key Laboratory of Mariculture & Stock Enhancement in North China Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian 116023, China.
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10
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Expression and intracellular localization of Nanos2-homologue protein in primordial germ cells and spermatogonial stem cells. ZYGOTE 2019; 27:82-88. [PMID: 30888312 DOI: 10.1017/s0967199419000066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
SummaryThe decision by germ cells to differentiate and undergo either oogenesis or spermatogenesis takes place during embryonic development and Nanos plays an important role in this process. The present study was designed to investigate the expression patterns in rat of Nanos2-homologue protein in primordial germ cells (PGCs) over different embryonic developmental days as well as in spermatogonial stem cells (SSCs). Embryos from three different embryonic days (E8.5, E10.5, E11.5) and SSCs were isolated and used to detect Nanos2-homologue protein using immunocytochemistry, western blotting, reverse transcription polymerase chain reaction (RT-PCR) and flow cytometry. Interestingly, Nanos2 expression was detected in PGCs at day E11.5 onwards and up to colonization of PGCs in the genital ridge of fetal gonads. No Nanos2 expression was found in PGCs during early embryonic days (E8.5 and 10.5). Furthermore, immunohistochemical and immunofluorescence data revealed that Nanos2 expression was restricted within a subpopulation of undifferentiated spermatogonia (As, single type A SSCs and Apr, paired type A SSCs). The same results were confirmed by our western blot and RT-PCR data, as Nanos2 protein and transcripts were detected only in PGCs from day E11.5 and in undifferentiated spermatogonia (As and Apr). Furthermore, Nanos2-positive cells were also immunodetected and sorted using flow cytometry from the THY1-positive SSCs population, and this strengthened the idea that these cells are stem cells. Our findings suggested that stage-specific expression of Nanos2 occurred on different embryonic developmental days, while during the postnatal period Nanos2 expression is restricted to As and Apr SSCs.
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11
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Campanale JP, Hamdoun A, Wessel GM, Su YH, Oulhen N. Methods to label, isolate, and image sea urchin small micromeres, the primordial germ cells (PGCs). Methods Cell Biol 2019; 150:269-292. [PMID: 30777180 PMCID: PMC6487853 DOI: 10.1016/bs.mcb.2018.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Small micromeres of the sea urchin are believed to be primordial germ cells (PGCs), fated to give rise to sperm or eggs in the adult. Sea urchin PGCs are formed at the fifth cleavage, undergo one additional division during blastulation, and migrate to the coelomic pouches of the pluteus larva. The goal of this chapter is to detail classical and modern techniques used to analyze primordial germ cell specification, gene expression programs, and cell behaviors in fixed and live embryos. The transparency of the sea urchin embryo enables both live imaging techniques and in situ RNA hybridization and immunolabeling for a detailed molecular characterization of these cells. Four approaches are presented to highlight small micromeres with fluorescent molecules for analysis by live and fixed cell microscopy: (1) small molecule dye accumulation during cleavage and blastula stages, (2) primordial germ cell targeted RNA expression using the Nanos untranslated regions, (3) fusing genes of interest with a Nanos2 targeting peptide, and (4) EdU and BrdU labeling. Applications of the live labeling techniques are discussed, including sorting by fluorescence-activated cell sorting for transcriptomic analysis, and, methods to image small micromere behavior in whole and dissociated embryos by live confocal microscopy. Finally, summary table of antibody and RNA probes as well as small molecule dyes to label small micromeres at a variety of developmental stages is provided.
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Affiliation(s)
- Joseph P Campanale
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
| | - Amro Hamdoun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, United States.
| | - Gary M Wessel
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, United States
| | - Yi-Hsien Su
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Nathalie Oulhen
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, RI, United States
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12
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Molina MD, Gache C, Lepage T. Expression of exogenous mRNAs to study gene function in echinoderm embryos. Methods Cell Biol 2019; 151:239-282. [PMID: 30948011 DOI: 10.1016/bs.mcb.2018.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
With the completion of the genome sequencing projects, a new challenge for developmental biologists is to assign a function to the thousands of genes identified. Expression of exogenous mRNAs is a powerful, versatile and rapid technique that can be used to study gene function during development of the sea urchin. This chapter describes how this technique can be used to analyze gene function in echinoderm embryos, how it can be combined with cell transplantation to perform mosaic analysis and how it can be applied to identify downstream targets genes of transcription factors and signaling pathways. We describe specific examples of the use of overexpression of mRNA to analyze gene function, mention the benefits and current limitations of the technique and emphasize the importance of using different controls to assess the specificity of the effects observed. Finally, this chapter details the different steps, vectors and protocols for in vitro production of mRNA and phenotypic analysis.
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Affiliation(s)
| | - Christian Gache
- Université Pierre et Marie Curie, Observatoire Océanologique de Villefranche sur Mer, UMR7009 CNRS, Paris, France
| | - Thierry Lepage
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France.
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13
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Oulhen N, Wessel G. A quiet space during rush hour: Quiescence in primordial germ cells. Stem Cell Res 2017; 25:296-299. [PMID: 29157935 DOI: 10.1016/j.scr.2017.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 10/25/2017] [Accepted: 11/03/2017] [Indexed: 10/18/2022] Open
Abstract
Quiescence is a common character in stem cells. Low cellular activity in these cells may function to minimize the potential damaging effects of oxidative stress, reduce the number of cells needed for tissue replenishment, and as a consequence, perhaps occupy unique niches. Quiescent stem cells are found in many adult human tissues, the hematopoietic stem cells are paradigmatic, and more recently it appears that stem cell of the germ line in many animals display quiescence characters. Here we explore the diversity of quiescence phenotypes in primordial germ cells, leveraging the diverse mechanisms of germ cell formation to extract evolutionary significance to common processes.
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Affiliation(s)
- Nathalie Oulhen
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, United States
| | - Gary Wessel
- Department of Molecular Biology, Cellular Biology, and Biochemistry, Brown University, Providence, RI 02912, United States.
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14
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Liu Q, Zhu L, Liu F, Hua M, Ding H, He S, Ren C, Liu M, Shen J. Function of Nanos1 gene in the development of reproductive organs of Schistosoma japonicum. Parasitol Res 2017; 116:1505-1513. [PMID: 28352943 DOI: 10.1007/s00436-017-5427-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 03/15/2017] [Indexed: 12/23/2022]
Abstract
Nanos is a necessary factor in the differentiation and migration of primordial germ cells. It is closely associated with the development of genitalia in a wide range of species. We questioned whether Nanos was involved in the reproductive organ development of Schistosoma japonicum. Firstly, by in situ hybridization, S. japonicum Nanos1 (SjNanos1) gene was expressed mainly in reproductive organs of S. japonicum. Then, the paired schistosome of 28 days post-infection (dpi) was transfected with SjNanos1 small interfering RNA three times and cultured in vitro for 10 days. SjNanos1 expression suppression in the mRNA and protein levels were confirmed compared to that of the controls. The morphological changes in reproductive organs and egg production were observed after SjNanos1 gene knockdown. The results observed by confocal laser scanning microscopy showed significant changes in the morphology of reproductive organs of parasites, especially the female ovaries, vitellarium, and the male testes, after RNAi. In addition, SjNanos1 silencing also induced the reduction of eggs, and affected the changes of reproduction-related genes, like Pumilio, CNOT6L, and Fs800. Therefore, our findings demonstrate that the SjNanos1 gene is essential in the development of reproductive organs and the egg production of S. japonicum.
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Affiliation(s)
- Quan Liu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Lulu Zhu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Fengchun Liu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Mengqing Hua
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Han Ding
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Siyu He
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Cuiping Ren
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China
| | - Miao Liu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China.
| | - Jijia Shen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, No. 81 Meishan Road, Hefei, Anhui, 230032, People's Republic of China.
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Farshchian M, Matin MM, Bahrami M, Geerts D, Dastpak M, Shahriyari M, Tajeran M, Mirahmadi M, Bahrami AR. Pluripotency induction in HEK293T cells by concurrent expression of STELLA, OCT4 and NANOS2. Biochem Biophys Res Commun 2016; 480:635-640. [DOI: 10.1016/j.bbrc.2016.10.108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 01/08/2023]
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