1
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Pamula MC, Lehmann R. How germ granules promote germ cell fate. Nat Rev Genet 2024:10.1038/s41576-024-00744-8. [PMID: 38890558 DOI: 10.1038/s41576-024-00744-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2024] [Indexed: 06/20/2024]
Abstract
Germ cells are the only cells in the body capable of giving rise to a new organism, and this totipotency hinges on their ability to assemble membraneless germ granules. These specialized RNA and protein complexes are hallmarks of germ cells throughout their life cycle: as embryonic germ granules in late oocytes and zygotes, Balbiani bodies in immature oocytes, and nuage in maturing gametes. Decades of developmental, genetic and biochemical studies have identified protein and RNA constituents unique to germ granules and have implicated these in germ cell identity, genome integrity and gamete differentiation. Now, emerging research is defining germ granules as biomolecular condensates that achieve high molecular concentrations by phase separation, and it is assigning distinct roles to germ granules during different stages of germline development. This organization of the germ cell cytoplasm into cellular subcompartments seems to be critical not only for the flawless continuity through the germline life cycle within the developing organism but also for the success of the next generation.
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Affiliation(s)
| | - Ruth Lehmann
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
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2
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Katagade V, Kandroo M, Ratnaparkhi A. Embryonic spatiotemporal expression pattern of Folded gastrulation suggests roles in multiple morphogenetic events and regulation by AbdA. G3 (BETHESDA, MD.) 2024; 14:jkae032. [PMID: 38366558 DOI: 10.1093/g3journal/jkae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/03/2023] [Accepted: 01/31/2024] [Indexed: 02/18/2024]
Abstract
In Drosophila, the signaling pathway activated by the ligand Folded gastrulation (Fog) is among the few known G protein-coupled receptor (GPCR) pathways to regulate cell shape change with a well-characterized role in gastrulation. However, an understanding of the spectrum of morphogenetic events regulated by Fog signaling is still lacking. Here, we present an analysis of the expression pattern and regulation of fog using a genome-engineered Fog::sfGFP line. We show that Fog expression is widespread and in tissues previously not associated with the signaling pathway including germ cells, trachea, and amnioserosa. In the central nervous system (CNS), we find that the ligand is expressed in multiple types of glia indicating a prominent role in the development of these cells. Consistent with this, we have identified 3 intronic enhancers whose expression in the CNS overlaps with Fog::sfGFP. Further, we show that enhancer-1, (fogintenh-1) located proximal to the coding exon is responsive to AbdA. Supporting this, we find that fog expression is downregulated in abdA mutants. Together, our study highlights the broad scope of Fog-GPCR signaling during embryogenesis and identifies Hox gene AbdA as a novel regulator of fog expression.
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Affiliation(s)
- Vrushali Katagade
- MACS-Agharkar Research Institute (Affiliated to Savitribai Phule Pune University), Developmental Biology Group, G.G. Agarkar Road, Pune 411 004, Maharashtra, India
| | - Manisha Kandroo
- MACS-Agharkar Research Institute (Affiliated to Savitribai Phule Pune University), Developmental Biology Group, G.G. Agarkar Road, Pune 411 004, Maharashtra, India
| | - Anuradha Ratnaparkhi
- MACS-Agharkar Research Institute (Affiliated to Savitribai Phule Pune University), Developmental Biology Group, G.G. Agarkar Road, Pune 411 004, Maharashtra, India
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3
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Pang LY, DeLuca S, Zhu H, Urban JM, Spradling AC. Chromatin and gene expression changes during female Drosophila germline stem cell development illuminate the biology of highly potent stem cells. eLife 2023; 12:RP90509. [PMID: 37831064 PMCID: PMC10575629 DOI: 10.7554/elife.90509] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023] Open
Abstract
Highly potent animal stem cells either self renew or launch complex differentiation programs, using mechanisms that are only partly understood. Drosophila female germline stem cells (GSCs) perpetuate without change over evolutionary time and generate cystoblast daughters that develop into nurse cells and oocytes. Cystoblasts initiate differentiation by generating a transient syncytial state, the germline cyst, and by increasing pericentromeric H3K9me3 modification, actions likely to suppress transposable element activity. Relatively open GSC chromatin is further restricted by Polycomb repression of testis or somatic cell-expressed genes briefly active in early female germ cells. Subsequently, Neijre/CBP and Myc help upregulate growth and reprogram GSC metabolism by altering mitochondrial transmembrane transport, gluconeogenesis, and other processes. In all these respects GSC differentiation resembles development of the totipotent zygote. We propose that the totipotent stem cell state was shaped by the need to resist transposon activity over evolutionary timescales.
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Affiliation(s)
- Liang-Yu Pang
- Howard Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - Steven DeLuca
- Howard Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - Haolong Zhu
- Howard Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - John M Urban
- Howard Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
| | - Allan C Spradling
- Howard Hughes Medical Institute, Carnegie Institution for ScienceBaltimoreUnited States
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4
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Doyle DA, Burian FN, Aharoni B, Klinder AJ, Menzel MM, Nifras GCC, Shabazz-Henry AL, Palma BU, Hidalgo GA, Sottolano CJ, Ortega BM, Niepielko MG. Germ Granule Evolution Provides Mechanistic Insight into Drosophila Germline Development. Mol Biol Evol 2023; 40:msad174. [PMID: 37527522 PMCID: PMC10414811 DOI: 10.1093/molbev/msad174] [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: 03/10/2023] [Revised: 07/22/2023] [Accepted: 07/26/2023] [Indexed: 08/03/2023] Open
Abstract
The copackaging of mRNAs into biomolecular condensates called germ granules is a conserved strategy to posttranscriptionally regulate germline mRNAs. In Drosophila melanogaster, mRNAs accumulate in germ granules by forming homotypic clusters, aggregates containing multiple transcripts from the same gene. Nucleated by Oskar (Osk), homotypic clusters are generated through a stochastic seeding and self-recruitment process that requires the 3' untranslated region (UTR) of germ granule mRNAs. Interestingly, the 3' UTR belonging to germ granule mRNAs, such as nanos (nos), have considerable sequence variations among Drosophila species and we hypothesized that this diversity influences homotypic clustering. To test our hypothesis, we investigated the homotypic clustering of nos and polar granule component (pgc) in four Drosophila species and concluded that clustering is a conserved process used to enrich germ granule mRNAs. However, we discovered germ granule phenotypes that included significant changes in the abundance of transcripts present in species' homotypic clusters, which also reflected diversity in the number of coalesced primordial germ cells within their embryonic gonads. By integrating biological data with computational modeling, we found that multiple mechanisms underlie naturally occurring germ granule diversity, including changes in nos, pgc, osk levels and/or homotypic clustering efficacy. Furthermore, we demonstrated how the nos 3' UTR from different species influences nos clustering, causing granules to have ∼70% less nos and increasing the presence of defective primordial germ cells. Our results highlight the impact that evolution has on germ granules, which should provide broader insight into processes that modify compositions and activities of other classes of biomolecular condensate.
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Affiliation(s)
- Dominique A Doyle
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Florencia N Burian
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Benjamin Aharoni
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Annabelle J Klinder
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Melissa M Menzel
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | | | | | - Bianca Ulrich Palma
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Gisselle A Hidalgo
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Christopher J Sottolano
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ, USA
| | - Bianca M Ortega
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
| | - Matthew G Niepielko
- School of Integrative Science and Technology, Kean University, Union, NJ, USA
- Department of Biological Sciences, Kean University, Union, NJ, USA
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5
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Doyle DA, Burian FN, Aharoni B, Klinder AJ, Menzel MM, Nifras GCC, Shabazz-Henry AL, Palma BU, Hidalgo GA, Sottolano CJ, Ortega BM, Niepielko MG. Evolutionary changes in germ granule mRNA content are driven by multiple mechanisms in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.529147. [PMID: 36865184 PMCID: PMC9980053 DOI: 10.1101/2023.02.21.529147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The co-packaging of mRNAs into biomolecular condensates called germ granules is a conserved strategy to post-transcriptionally regulate mRNAs that function in germline development and maintenance. In D. melanogaster, mRNAs accumulate in germ granules by forming homotypic clusters, aggregates that contain multiple transcripts from a specific gene. Nucleated by Oskar (Osk), homotypic clusters in D. melanogaster are generated through a stochastic seeding and self-recruitment process that requires the 3' UTR of germ granule mRNAs. Interestingly, the 3' UTR belonging to germ granule mRNAs, such as nanos (nos), have considerable sequence variations among Drosophila species. Thus, we hypothesized that evolutionary changes in the 3' UTR influences germ granule development. To test our hypothesis, we investigated the homotypic clustering of nos and polar granule component (pgc) in four Drosophila species and concluded that homotypic clustering is a conserved developmental process used to enrich germ granule mRNAs. Additionally, we discovered that the number of transcripts found in nos and/or pgc clusters could vary significantly among species. By integrating biological data with computational modeling, we determined that multiple mechanisms underlie naturally occurring germ granule diversity, including changes in nos, pgc, osk levels, and/or homotypic clustering efficacy. Finally, we found that the nos 3' UTR from different species can alter the efficacy of nos homotypic clustering, resulting in germ granules with reduced nos accumulation. Our findings highlight the impact that evolution has on the development of germ granules and may provide insight into processes that modify the content of other classes of biomolecular condensates.
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Affiliation(s)
- Dominique A. Doyle
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Florencia N. Burian
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Benjamin Aharoni
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Annabelle J. Klinder
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Melissa M. Menzel
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Gerard Carlo C. Nifras
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Ahad L. Shabazz-Henry
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Bianca Ulrich Palma
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Gisselle A. Hidalgo
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Christopher J. Sottolano
- Center for Computational and Integrative Biology, Rutgers, The State University of New Jersey, Camden, NJ 08103, USA
| | - Bianca M. Ortega
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
| | - Matthew G. Niepielko
- School of Integrative Science and Technology, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
- Department of Biological Sciences, Kean University, 1000 Morris Ave., Union, NJ 07083, USA
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6
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Li W, Liu W, Mo C, Yi M, Gui J. Two Novel lncRNAs Regulate Primordial Germ Cell Development in Zebrafish. Cells 2023; 12:cells12040672. [PMID: 36831339 PMCID: PMC9954370 DOI: 10.3390/cells12040672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/22/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) are regulatory transcripts in various biological processes. However, the role of lncRNAs in germline development remains poorly understood, especially for fish primordial germ cell (PGC) development. In this study, the lncRNA profile of zebrafish PGC was revealed by single cell RNA-sequencing and bioinformatic prediction. We established the regulation network of lncRNA-mRNA associated with PGC development, from which we identified three novel lncRNAs-lnc172, lnc196, and lnc304-highly expressing in PGCs and gonads. Fluorescent in situ hybridization indicated germline-specific localization of lnc196 and lnc304 in the cytoplasm and nucleus of spermatogonia, spermatocyte, and occyte, and they were co-localized with vasa in the cytoplasm of the spermatogonia. By contrast, lnc172 was localized in the cytoplasm of male germline, myoid cells and ovarian somatic cells. Loss- and gain-of-function experiments demonstrated that knockdown and PGC-specific overexpression of lnc304 as well as universal overexpression of lnc172 significantly disrupted PGC development. In summary, the present study revealed the lncRNA profile of zebrafish PGC and identified two novel lncRNAs associated with PGC development, providing new insights for understanding the regulatory mechanism of PGC development.
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Affiliation(s)
- Wenjing Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Wei Liu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Chengyu Mo
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Meisheng Yi
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
- Correspondence: (M.Y.); (J.G.)
| | - Jianfang Gui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Innovation Academy of Seed Design, Chinese Academy of Sciences, Wuhan 420072, China
- Correspondence: (M.Y.); (J.G.)
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7
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Colonnetta MM, Schedl P, Deshpande G. Germline/soma distinction in Drosophila embryos requires regulators of zygotic genome activation. eLife 2023; 12:78188. [PMID: 36598809 PMCID: PMC9812407 DOI: 10.7554/elife.78188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 12/23/2022] [Indexed: 01/05/2023] Open
Abstract
In Drosophila melanogaster embryos, somatic versus germline identity is the first cell fate decision. Zygotic genome activation (ZGA) orchestrates regionalized gene expression, imparting specific identity on somatic cells. ZGA begins with a minor wave that commences at nuclear cycle (NC)8 under the guidance of chromatin accessibility factors (Zelda, CLAMP, GAF), followed by the major wave during NC14. By contrast, primordial germ cell (PGC) specification requires maternally deposited and posteriorly anchored germline determinants. This is accomplished by a centrosome coordinated release and sequestration of germ plasm during the precocious cellularization of PGCs in NC10. Here, we report a novel requirement for Zelda and CLAMP during the establishment of the germline/soma distinction. When their activity is compromised, PGC determinants are not properly sequestered, and specification is disrupted. Conversely, the spreading of PGC determinants from the posterior pole adversely influences transcription in the neighboring somatic nuclei. These reciprocal aberrations can be correlated with defects in centrosome duplication/separation that are known to induce inappropriate transmission of the germ plasm. Interestingly, consistent with the ability of bone morphogenetic protein (BMP) signaling to influence specification of embryonic PGCs, reduction in the transcript levels of a BMP family ligand, decapentaplegic (dpp), is exacerbated at the posterior pole.
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Affiliation(s)
- Megan M Colonnetta
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Paul Schedl
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Girish Deshpande
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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8
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Colonnetta MM, Goyal Y, Johnson HE, Syal S, Schedl P, Deshpande G. Preformation and epigenesis converge to specify primordial germ cell fate in the early Drosophila embryo. PLoS Genet 2022; 18:e1010002. [PMID: 34986144 PMCID: PMC8765614 DOI: 10.1371/journal.pgen.1010002] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 01/18/2022] [Accepted: 12/17/2021] [Indexed: 11/24/2022] Open
Abstract
A critical step in animal development is the specification of primordial germ cells (PGCs), the precursors of the germline. Two seemingly mutually exclusive mechanisms are implemented across the animal kingdom: epigenesis and preformation. In epigenesis, PGC specification is non-autonomous and depends on extrinsic signaling pathways. The BMP pathway provides the key PGC specification signals in mammals. Preformation is autonomous and mediated by determinants localized within PGCs. In Drosophila, a classic example of preformation, constituents of the germ plasm localized at the embryonic posterior are thought to be both necessary and sufficient for proper determination of PGCs. Contrary to this longstanding model, here we show that these localized determinants are insufficient by themselves to direct PGC specification in blastoderm stage embryos. Instead, we find that the BMP signaling pathway is required at multiple steps during the specification process and functions in conjunction with components of the germ plasm to orchestrate PGC fate. Proper specification of primordial germ cells (PGCs) is crucial as PGCs serve as the precursors of germline stem cells. To specify PGC fate, invertebrates rely upon cell autonomous preformation involving maternally deposited germ plasm. In Drosophila melanogaster, to insulate newly formed PGCs from the adverse effects of the cell-cell signaling pathways, germ plasm determinants silence transcription and attenuate the cell cycle. However, our data on the BMP signaling pathway challenge this long-held view of PGC specification and suggest that appropriate specification of embryonic PGCs is sensitive to the BMP ligand, decapentaplegic (dpp), and its cognate receptor, thickveins. We find that PGCs are not only capable of responding to BMP signals from the soma, but also that these signals impact the proper determination of the germ cells. Based on these unanticipated similarities between mammals and flies, we propose a model integrating contribution of both the cell-autonomous (preformation) and non-autonomous (epigenesis) pathways during PGC determination. Consistent with the model, we have observed dominant genetic interactions between, oskar, the maternal determinant of PGC fate, and the BMP pathway ligand dpp.
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Affiliation(s)
- Megan M. Colonnetta
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Yogesh Goyal
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Heath E. Johnson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Sapna Syal
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
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9
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Mo C, Li W, Jia K, Liu W, Yi M. Proper Balance of Small GTPase rab10 Is Critical for PGC Migration in Zebrafish. Int J Mol Sci 2021; 22:11962. [PMID: 34769390 PMCID: PMC8584686 DOI: 10.3390/ijms222111962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022] Open
Abstract
MicroRNAs (miRNAs) play important roles in post-transcriptional repression in nearly every biological process including germ cell development. Previously, we have identified a zebrafish germ plasm-specific miRNA miR-202-5p, which regulates PGC migration through targeting cdc42se1 to protect cdc42 expression. However, knockdown of cdc42se1 could not significantly rescue PGC migration in maternal miR-202 mutant (MmiR-202) embryos, indicating that there are other target genes of miR-202-5p required for the regulation of PGC migration. Herein, we revealed the transcriptional profiles of wild type and MmiR-202 PGCs and obtained 129 differentially expressed genes (DEGs), of which 42 DEGs were enriched cell migration-related signaling pathways. From these DEGs, we identified two novel miR-202-5p target genes prdm12b and rab10. Furthermore, we found that disruption of rab10 expression led to significantly migratory defects of PGC by overexpression of rab10 siRNA, or WT, inactive as well as active forms of rab10 mRNA, and WT rab10 overexpression mediated migratory defects could be partially but significantly rescued by overexpression of miR-202-5p, demonstrating that rab10 is an important factor involved miR-202-5p mediated regulation of PGC migration. Taken together, the present results provide significant information for understanding the molecular mechanism by which miR-202-5p regulates PGC migration in zebrafish.
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Affiliation(s)
- Chengyu Mo
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (C.M.); (W.L.); (K.J.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Wenjing Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (C.M.); (W.L.); (K.J.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Kuntong Jia
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (C.M.); (W.L.); (K.J.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Wei Liu
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (C.M.); (W.L.); (K.J.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
| | - Meisheng Yi
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; (C.M.); (W.L.); (K.J.)
- Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510275, China
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10
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Colonnetta MM, Lym LR, Wilkins L, Kappes G, Castro EA, Ryder PV, Schedl P, Lerit DA, Deshpande G. Antagonism between germ cell-less and Torso receptor regulates transcriptional quiescence underlying germline/soma distinction. eLife 2021; 10:54346. [PMID: 33459591 PMCID: PMC7843132 DOI: 10.7554/elife.54346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/15/2021] [Indexed: 11/13/2022] Open
Abstract
Transcriptional quiescence, an evolutionarily conserved trait, distinguishes the embryonic primordial germ cells (PGCs) from their somatic neighbors. In Drosophila melanogaster, PGCs from embryos maternally compromised for germ cell-less (gcl) misexpress somatic genes, possibly resulting in PGC loss. Recent studies documented a requirement for Gcl during proteolytic degradation of the terminal patterning determinant, Torso receptor. Here we demonstrate that the somatic determinant of female fate, Sex-lethal (Sxl), is a biologically relevant transcriptional target of Gcl. Underscoring the significance of transcriptional silencing mediated by Gcl, ectopic expression of a degradation-resistant form of Torso (torsoDeg) can activate Sxl transcription in PGCs, whereas simultaneous loss of torso-like (tsl) reinstates the quiescent status of gcl PGCs. Intriguingly, like gcl mutants, embryos derived from mothers expressing torsoDeg in the germline display aberrant spreading of pole plasm RNAs, suggesting that mutual antagonism between Gcl and Torso ensures the controlled release of germ-plasm underlying the germline/soma distinction.
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Affiliation(s)
- Megan M Colonnetta
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Lauren R Lym
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Lillian Wilkins
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Gretchen Kappes
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Elias A Castro
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Pearl V Ryder
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Paul Schedl
- Department of Molecular Biology, Princeton University, Princeton, United States
| | - Dorothy A Lerit
- Department of Cell Biology, Emory University School of Medicine, Atlanta, United States
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, United States
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11
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Chen Y, Ho L, Tergaonkar V. sORF-Encoded MicroPeptides: New players in inflammation, metabolism, and precision medicine. Cancer Lett 2020; 500:263-270. [PMID: 33157158 DOI: 10.1016/j.canlet.2020.10.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 12/30/2022]
Abstract
Significant technological advances have enabled the discovery and identification of a new class of molecules, micropeptides or small ORF encoded peptides (SEPs) within non-coding RNAs (ncRNAs). As ncRNAs are well known to be transcriptionally silent, the discovery of SEPs implies that many ncRNAs are misannotated or play both coding and non-coding functions. SEPs have reportedly diverse regulatory roles in embryogenesis, myogenesis, inflammation, diseases, and cancer. SEPs appearing in different subcellular compartments show distinct functions. In this review, we summarized the functions of SEPs that have been characterized thus far. As SEPs are amenable to therapeutic development as biologics, understanding their underlying functions will provide novel targets for the treatment of inflammatory or metabolic disorders.
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Affiliation(s)
- Ying Chen
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, 138673, Singapore.
| | - Lena Ho
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, 138673, Singapore; Cardiovascular Metabolic Disorders Program, Duke-NUS Graduate School, Singapore; Institute of Medical Biology, A*STAR, Singapore
| | - Vinay Tergaonkar
- Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Singapore, 138673, Singapore; Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, 117597, Singapore.
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12
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Piprek RP, Kloc M, Mizia P, Kubiak JZ. The Central Role of Cadherins in Gonad Development, Reproduction, and Fertility. Int J Mol Sci 2020; 21:E8264. [PMID: 33158211 PMCID: PMC7663743 DOI: 10.3390/ijms21218264] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 12/15/2022] Open
Abstract
Cadherins are a group of membrane proteins responsible for cell adhesion. They are crucial for cell sorting and recognition during the morphogenesis, but they also play many other roles such as assuring tissue integrity and resistance to stretching, mechanotransduction, cell signaling, regulation of cell proliferation, apoptosis, survival, carcinogenesis, etc. Within the cadherin superfamily, E- and N-cadherin have been especially well studied. They are involved in many aspects of sexual development and reproduction, such as germline development and gametogenesis, gonad development and functioning, and fertilization. E-cadherin is expressed in the primordial germ cells (PGCs) and also participates in PGC migration to the developing gonads where they become enclosed by the N-cadherin-expressing somatic cells. The differential expression of cadherins is also responsible for the establishment of the testis or ovary structure. In the adult testes, N-cadherin is responsible for the integrity of the seminiferous epithelium, regulation of sperm production, and the establishment of the blood-testis barrier. Sex hormones regulate the expression and turnover of N-cadherin influencing the course of spermatogenesis. In the adult ovaries, E- and N-cadherin assure the integrity of ovarian follicles and the formation of corpora lutea. Cadherins are expressed in the mature gametes and facilitate the capacitation of sperm in the female reproductive tract and gamete contact during fertilization. The germ cells and accompanying somatic cells express a series of different cadherins; however, their role in gonads and reproduction is still unknown. In this review, we show what is known and unknown about the role of cadherins in the germline and gonad development, and we suggest topics for future research.
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Affiliation(s)
- Rafał P. Piprek
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Krakow, Poland;
| | - Malgorzata Kloc
- The Houston Methodist Research Institute, Houston, TX 77030, USA;
- Department of Surgery, The Houston Methodist Hospital, Houston, TX 77030, USA
- MD Anderson Cancer Center, University of Texas, Houston, TX 77030, USA
| | - Paulina Mizia
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387 Krakow, Poland;
| | - Jacek Z. Kubiak
- Cycle Group, Institute of Genetics and Development of Rennes, Faculty of Medicine, UnivRennes, UMR 6290 CNRS/UR1, F-35000 Rennes, France
- Department of Regenerative Medicine and Cell Biology, Military Institute of Hygiene and Epidemiology (WIHE), 01-163 Warsaw, Poland
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13
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Jin Y, Liu W, Xiang Y, Zhang W, Zhang H, Jia K, Yi M. Maternal miR-202-5p is required for zebrafish primordial germ cell migration by protecting small GTPase Cdc42. J Mol Cell Biol 2020; 12:530-542. [PMID: 31742346 PMCID: PMC7493028 DOI: 10.1093/jmcb/mjz103] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 06/10/2019] [Accepted: 07/29/2019] [Indexed: 01/17/2023] Open
Abstract
In many lower animals, germ cell formation, migration, and maintenance depend on maternally provided determinants in germ plasm. In zebrafish, these processes have been extensively studied in terms of RNA-binding proteins and other coding genes. The role of small non-coding RNAs in the regulation of primordial germ cell (PGC) development remains largely unknown and poorly investigated, even though growing interests for the importance of miRNAs involved in a wide variety of biological processes. Here, we reported the role and mechanism of the germ plasm-specific miRNA miR-202-5p in PGC migration: (i) both maternal loss and knockdown of miR-202-5p impaired PGC migration indicated by the mislocalization and reduced number of PGCs; (ii) cdc42se1 was a direct target gene of miR-202-5p, and overexpression of Cdc42se1 in PGCs caused PGC migration defects similar to those observed in loss of miR-202-5p mutants; (iii) Cdc42se1 not only interacted with Cdc42 but also inhibited cdc42 transcription, and overexpression of Cdc42 could rescue PGC migration defects in Cdc42se1 overexpressed embryos. Thus, miR-202-5p regulates PGC migration by directly targeting and repressing Cdc42se1 to protect the expression of Cdc42, which interacts with actin to direct PGC migration.
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Affiliation(s)
- Yilin Jin
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
| | - Wei Liu
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
| | - Yangxi Xiang
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
| | - Wanwan Zhang
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
| | - Hong Zhang
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
| | - Kuntong Jia
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
- Correspondence to: Meisheng Yi, E-mail: ; Kuntong Jia, E-mail:
| | - Meisheng Yi
- School of Marine Sciences Sun Yat-sen University, Guangzhou 519082, China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Sun Yat-sen University, Guangzhou 519082, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou 519082, China
- Correspondence to: Meisheng Yi, E-mail: ; Kuntong Jia, E-mail:
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14
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Syal S, Ng C, Kim Y, Janbieh J, Govind S, Deshpande G. Reactive oxygen species signaling in primordial germ cell development in Drosophila embryos. Genesis 2020; 58:e23362. [PMID: 32302036 DOI: 10.1002/dvg.23362] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/04/2020] [Accepted: 03/23/2020] [Indexed: 12/30/2022]
Abstract
REDOX mechanisms that induce biosynthesis of the reactive oxygen species (ROS) have attracted considerable attention due to both the deleterious and beneficial responses elicited by the reactive radical. In several organisms including Drosophila melanogaster, modulation of ROS activity is thought to be crucial for the maintenance of cell fates in developmental contexts. Interestingly, REDOX mechanisms have been shown to be involved in maintaining progenitor fate of stem cells as well as their proliferation and differentiation. Here, we have explored the possible functions of ROS during proper specification and developmental progression of embryonic primordial germ cells (PGCs). Indicating its potential involvement in these processes, ROS can be detected in the embryonic PGCs and the surrounding somatic cells from very early stages of embryogenesis. Using both "loss" and "gain" of function mutations in two different components of the REDOX pathway, we show that ROS levels are likely to be critical in maintaining germ cell behavior, including their directed migration. Altering the activity of a putative regulator of ROS also adversely influences the ability of PGCs to adhere to one another in cellular blastoderm embryos, suggesting potential involvement of this pathway in orchestrating different phases of germ cell migration.
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Affiliation(s)
- Sapna Syal
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Chris Ng
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Yunah Kim
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Javier Janbieh
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Shubha Govind
- The Graduate Center of the City University of New York, New York, New York, USA
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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15
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Zheng T, Nakamoto A, Kumano G. H3K27me3 suppresses sister-lineage somatic gene expression in late embryonic germline cells of the ascidian, Halocynthia roretzi. Dev Biol 2020; 460:200-214. [PMID: 31904374 DOI: 10.1016/j.ydbio.2019.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/21/2019] [Accepted: 12/29/2019] [Indexed: 10/25/2022]
Abstract
Protection of the germline from somatic differentiation programs is crucial for germ cell development. In many animals, whose germline development relies on the maternally inherited germ plasm, such protection in particular at early stages of embryogenesis is achieved by maternally localized global transcriptional repressors, such as PIE-1 of Caenorhabditis elegans, Pgc of Drosophila melanogaster and Pem of ascidians. However, zygotic gene expression starts in later germline cells eventually and mechanisms by which somatic gene expression is selectively kept under repression in the transcriptionally active cells are poorly understood. By using the ascidian species Halocynthia roretzi, we found that H3K27me3, a repressive transcription-related chromatin mark, became enriched in germline cells starting at the 64-cell stage when Pem protein level and its contribution to transcriptional repression decrease. Interestingly, inhibition of H3K27me3 together with Pem knockdown resulted in ectopic expression in germline cells of muscle developmental genes Muscle actin (MA4) and Snail, and of Clone 22 (which is expressed in all somatic but not germline cells), but not of other tissue-specific genes such as the notochord gene Brachyury, the nerve cord marker ETR-1 and a heart precursor gene Mesp, at the 110-cell stage. Importantly, these ectopically expressed genes are normally expressed in the germline sister cells (B7.5), the last somatic lineage separated from the germline. Also, the ectopic expression of MA4 was dependent on a maternally localized muscle determinant Macho-1. Taken together, we propose that H3K27me3 may be responsible for selective transcriptional repression for somatic genes in later germline cells in Halocynthia embryos and that the preferential repression of germline sister-lineage genes may be related to the mechanism of germline segregation in ascidian embryos, where the germline is segregated progressively by successive asymmetric cell divisions during cell cleavage stages. Together with findings from C. elegans and D. melanogaster, our data for this urochordate animal support the proposal for a mechanism, conserved widely throughout the animal kingdom, where germline transcriptional repression is mediated initially by maternally localized factors and subsequently by a chromatin-based mechanism.
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Affiliation(s)
- Tao Zheng
- Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Japan.
| | - Ayaki Nakamoto
- Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Japan
| | - Gaku Kumano
- Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Japan
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16
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Morita S, Ota R, Hayashi M, Kobayashi S. Repression of G1/S Transition by Transient Inhibition of miR-10404 Expression in Drosophila Primordial Germ Cells. iScience 2020; 23:100950. [PMID: 32179474 PMCID: PMC7075979 DOI: 10.1016/j.isci.2020.100950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/20/2020] [Accepted: 02/24/2020] [Indexed: 01/30/2023] Open
Abstract
Cell-cycle quiescence is a common feature of early germline development in many animal species. In Drosophila germline progenitors (pole cells), both G2/M and G1/S transitions are blocked. G2/M transition is repressed by maternal Nanos through suppression of Cyclin B production. However, the molecular mechanism underlying blockage of G1/S transition remains elusive. We found that repression of miR-10404 expression is required to block G1/S transition in pole cells. Expression of miR-10404, a microRNA encoded within the internal transcribed spacer 1 of rDNA, is repressed in early pole cells by maternal polar granule component. This repression delays the degradation of maternal dacapo mRNA, which encodes an inhibitor of G1/S transition. Moreover, derepression of G1/S transition in pole cells causes defects in their maintenance and their migration into the gonads. Our observations reveal the mechanism inhibiting G1/S transition in pole cells and its requirement for proper germline development.
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Affiliation(s)
- Shumpei Morita
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan; Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Ryoma Ota
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Makoto Hayashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan; Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Satoru Kobayashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan; Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
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17
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Flora P, Wong-Deyrup SW, Martin ET, Palumbo RJ, Nasrallah M, Oligney A, Blatt P, Patel D, Fuchs G, Rangan P. Sequential Regulation of Maternal mRNAs through a Conserved cis-Acting Element in Their 3' UTRs. Cell Rep 2019; 25:3828-3843.e9. [PMID: 30590052 PMCID: PMC6328254 DOI: 10.1016/j.celrep.2018.12.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/28/2018] [Accepted: 11/30/2018] [Indexed: 12/31/2022] Open
Abstract
Maternal mRNAs synthesized during oogenesis initiate the development of future generations. Some maternal mRNAs are either somatic or germline determinants and must be translationally repressed until embryogenesis. However, the translational repressors themselves are temporally regulated. We used polar granule component (pgc), a Drosophila maternal mRNA, to ask how maternal transcripts are repressed while the regulatory landscape is shifting. pgc, a germline determinant, is translationally regulated throughout oogenesis. We find that different conserved RNA-binding proteins bind a 10-nt sequence in the 3′ UTR of pgc mRNA to continuously repress translation at different stages of oogenesis. Pumilio binds to this sequence in undifferentiated and early-differentiating oocytes to block Pgc translation. After differentiation, Bruno levels increase, allowing Bruno to bind the same sequence and take over translational repression of pgc mRNA. We have identified a class of maternal mRNAs that are regulated similarly, including zelda, the activator of the zygotic genome. Flora et al. show that pgc, a germline determinant, is translationally regulated throughout oogenesis. Different conserved RBPs bind a 10-nt sequence in the 3′ UTR to continuously repress translation throughout oogenesis. This mode of regulation applies to a class of maternal mRNAs, including zelda, the activator of the zygotic genome.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Siu Wah Wong-Deyrup
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Elliot Todd Martin
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Ryan J Palumbo
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Mohamad Nasrallah
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Andrew Oligney
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Patrick Blatt
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Dhruv Patel
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Gabriele Fuchs
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY 12222, USA.
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18
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Quan H, Arsala D, Lynch JA. Transcriptomic and functional analysis of the oosome, a unique form of germ plasm in the wasp Nasonia vitripennis. BMC Biol 2019; 17:78. [PMID: 31601213 PMCID: PMC6785909 DOI: 10.1186/s12915-019-0696-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 08/30/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND The oosome is the germline determinant in the wasp Nasonia vitripennis and is homologous to the polar granules of Drosophila. Despite a common evolutionary origin and developmental role, the oosome is morphologically quite distinct from polar granules. It is a solid sphere that migrates within the cytoplasm before budding out and forming pole cells. RESULTS To gain an understanding of both the molecular basis of oosome development and the conserved essential features of germ plasm, we quantified and compared transcript levels between embryo fragments that contained the oosome and those that did not. The identity of the differentially localized transcripts indicated that Nasonia uses a distinct set of molecules to carry out conserved germ plasm functions. In addition, functional testing of a sample of localized transcripts revealed potentially novel mechanisms of ribonucleoprotein assembly and pole cell cellularization in the wasp. CONCLUSIONS Our results demonstrate that the composition of germ plasm varies significantly within Holometabola, as very few mRNAs share localization to the oosome and polar granules. Some of this variability appears to be related to the unique properties of the oosome relative to the polar granules in Drosophila, and some may be related to differences in pole formation between species. This work will serve as the basis for further investigation into the patterns of germline determinant evolution among insects, the molecular basis of the unique properties of the oosome, and the incorporation of novel components into developmental networks.
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Affiliation(s)
- Honghu Quan
- Department of Pathology and Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105 USA
| | - Deanna Arsala
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607 USA
| | - Jeremy A. Lynch
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607 USA
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19
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Trcek T, Lehmann R. Germ granules in Drosophila. Traffic 2019; 20:650-660. [PMID: 31218815 PMCID: PMC6771631 DOI: 10.1111/tra.12674] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/26/2019] [Accepted: 06/14/2019] [Indexed: 12/22/2022]
Abstract
Germ granules are hallmarks of all germ cells. Early ultrastructural studies in Drosophila first described these membraneless granules in the oocyte and early embryo as filled with amorphous to fibrillar material mixed with RNA. Genetic studies identified key protein components and specific mRNAs that regulate germ cell‐specific functions. More recently these ultrastructural studies have been complemented by biophysical analysis describing germ granules as phase‐transitioned condensates. In this review, we provide an overview that connects the composition of germ granules with their function in controlling germ cell specification, formation and migration, and illuminate these mysterious condensates as the gatekeepers of the next generation.
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Affiliation(s)
- Tatjana Trcek
- HHMI, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, New York
| | - Ruth Lehmann
- HHMI, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU School of Medicine, New York, New York
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20
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Asaoka M, Hanyu-Nakamura K, Nakamura A, Kobayashi S. Maternal Nanos inhibits Importin-α2/Pendulin-dependent nuclear import to prevent somatic gene expression in the Drosophila germline. PLoS Genet 2019; 15:e1008090. [PMID: 31091233 PMCID: PMC6519790 DOI: 10.1371/journal.pgen.1008090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/13/2019] [Indexed: 01/15/2023] Open
Abstract
Repression of somatic gene expression in germline progenitors is one of the critical mechanisms involved in establishing the germ/soma dichotomy. In Drosophila, the maternal Nanos (Nos) and Polar granule component (Pgc) proteins are required for repression of somatic gene expression in the primordial germ cells, or pole cells. Pgc suppresses RNA polymerase II-dependent global transcription in pole cells, but it remains unclear how Nos represses somatic gene expression. Here, we show that Nos represses somatic gene expression by inhibiting translation of maternal importin-α2 (impα2) mRNA. Mis-expression of Impα2 caused aberrant nuclear import of a transcriptional activator, Ftz-F1, which in turn activated a somatic gene, fushi tarazu (ftz), in pole cells when Pgc-dependent transcriptional repression was impaired. Because ftz expression was not fully activated in pole cells in the absence of either Nos or Pgc, we propose that Nos-dependent repression of nuclear import of transcriptional activator(s) and Pgc-dependent suppression of global transcription act as a 'double-lock' mechanism to inhibit somatic gene expression in germline progenitors.
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Affiliation(s)
- Miho Asaoka
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kazuko Hanyu-Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Satoru Kobayashi
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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21
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Hanyu-Nakamura K, Matsuda K, Cohen SM, Nakamura A. Pgc suppresses the zygotically acting RNA decay pathway to protect germ plasm RNAs in the Drosophila embryo. Development 2019; 146:dev.167056. [PMID: 30890569 DOI: 10.1242/dev.167056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 03/11/2019] [Indexed: 11/20/2022]
Abstract
Specification of germ cells is pivotal to ensure continuation of animal species. In many animal embryos, germ cell specification depends on maternally supplied determinants in the germ plasm. Drosophila polar granule component (pgc) mRNA is a component of the germ plasm. pgc encodes a small protein that is transiently expressed in newly formed pole cells, the germline progenitors, where it globally represses mRNA transcription. pgc is also required for pole cell survival, but the mechanism linking transcriptional repression to pole cell survival remains elusive. We report that pole cells lacking pgc show premature loss of germ plasm mRNAs, including the germ cell survival factor nanos, and undergo apoptosis. We found that pgc- pole cells misexpress multiple miRNA genes. Reduction of miRNA pathway activity in pgc- embryos partially suppressed germ plasm mRNA degradation and pole cell death, suggesting that Pgc represses zygotic miRNA transcription in pole cells to protect germ plasm mRNAs. Interestingly, germ plasm mRNAs are protected from miRNA-mediated degradation in vertebrates, albeit by a different mechanism. Thus, independently evolved mechanisms are used to silence miRNAs during germ cell specification.
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Affiliation(s)
- Kazuko Hanyu-Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan.,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Kazuki Matsuda
- Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan
| | - Stephen M Cohen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N Copenhagen, Denmark
| | - Akira Nakamura
- Department of Germline Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, Japan .,Laboratory for Germline Development, RIKEN Center for Developmental Biology, Kobe, Hyogo 650-0047, Japan.,Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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22
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Liu W, Zhang H, Xiang Y, Jia K, Luo M, Yi M. Molecular characterization of vasa homologue in marbled goby, Oxyeleotris marmorata: Transcription and localization analysis during gametogenesis and embryogenesis. Comp Biochem Physiol B Biochem Mol Biol 2018; 229:42-50. [PMID: 30590176 DOI: 10.1016/j.cbpb.2018.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 02/06/2023]
Abstract
Identification of germ cell markers is important for investigating reproduction biology in fish. Vasa is one of the most studied germ cell markers in mammals and lower vertebrates including fish. Here, we characterized a vasa homologue from the fish marbled goby (Oxyeleotris marmorata), termed omvasa. The full length of omvasa cDNA is 2344 bp and encodes 658 amino acids, sharing high identities with Vasa homologues of other vertebrates. OmVasa protein contains 15 RG/RGG repeats at N-terminus, 2 ATPase motifs, as well as RNA unwinding and RNA binding domains at C-terminus. Phylogenetic tree showed that omVasa had the closest relationship with the Vasa homologue from the fish Boleophthalmus pectinirostris, the great blue-spotted mudskipper. qRT-PCR analysis indicated that omvasa was specifically transcribed in gonads, and the transcription level was gradually increased during oocyte development. The germ cell-specific distribution of omvasa mRNA was revealed by fluorescent in situ hybridization. In ovary, the signal of omvasa RNA displayed strong-weak-strong dynamics from oogonia over pre-vitellogenic oocytes to vitellogenic oocytes. In testis, omvasa signal was strong in spermatogonia, modest in spermatocytes but undetectable in spermatids and somatic cells. During embryogenesis, the transcription of omvasa mRNA was high at blastula stage, gradually decreased from gastrula stage and maintained at a low level in later developmental stages. Whole mount in situ hybridization indicated that omvasa mRNA was specific to primordial germ cells (PGCs). In summary, marbled goby vasa is a germ cell-specific transcript during gametogenesis, and can be used as an ideal marker for tracing PGC formation and migration, which is pivotal to germ cell manipulation in this species.
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Affiliation(s)
- Wei Liu
- Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Hong Zhang
- Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Yangxi Xiang
- Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Kuntong Jia
- Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Mingfei Luo
- Zhuhai Modern Agriculture Development Center, Guangdong, China.
| | - Meisheng Yi
- Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China.
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23
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PIE-1 Translation in the Germline Lineage Contributes to PIE-1 Asymmetry in the Early Caenorhabditis elegans Embryo. G3-GENES GENOMES GENETICS 2018; 8:3791-3801. [PMID: 30279189 PMCID: PMC6288838 DOI: 10.1534/g3.118.200744] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the C. elegans embryo, the germline lineage is established through successive asymmetric cell divisions that each generate a somatic and a germline daughter cell. PIE-1 is an essential maternal factor that is enriched in embryonic germline cells and is required for germline specification. We estimated the absolute concentration of PIE-1::GFP in germline cells and find that PIE-1::GFP concentration increases by roughly 4.5 fold, from 92 nM to 424 nM, between the 1 and 4-cell stages. Previous studies have shown that the preferential inheritance of PIE-1 by germline daughter cells and the degradation of PIE-1 in somatic cells are important for PIE-1 enrichment in germline cells. In this study, we provide evidence that the preferential translation of maternal PIE-1::GFP transcripts in the germline also contributes to PIE-1::GFP enrichment. Through an RNAi screen, we identified Y14 and MAG-1 (Drosophila tsunagi and mago nashi) as regulators of embryonic PIE-1::GFP levels. We show that Y14 and MAG-1 do not regulate PIE-1 degradation, segregation or synthesis in the early embryo, but do regulate the concentration of maternally-deposited PIE-1::GFP. Taken together, or findings point to an important role for translational control in the regulation of PIE-1 levels in the germline lineage.
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24
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Lebedeva LA, Yakovlev KV, Kozlov EN, Schedl P, Deshpande G, Shidlovskii YV. Transcriptional quiescence in primordial germ cells. Crit Rev Biochem Mol Biol 2018; 53:579-595. [PMID: 30280955 PMCID: PMC8729227 DOI: 10.1080/10409238.2018.1506733] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/09/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022]
Abstract
In most animal species, newly formed primordial germ cells (PGCs) acquire the special characteristics that distinguish them from the surrounding somatic cells. Proper fate specification of the PGCs is coupled with transcriptional quiescence, whether they are segregated by determinative or inductive mechanisms. Inappropriate differentiation of PGCs into somatic cells is thought to be prevented due to repression of RNA polymerase (Pol) II-dependent transcription. In the case of a determinative mode of PGC formation (Drosophila, Caenorhabditis elegans, etc.), there is a broad downregulation of Pol II activity. By contrast, PGCs display only gene-specific repression in organisms that rely on inductive signaling-based mechanism (e.g., mice). In addition to the global block of Pol II activity in PGCs, gene expression can be suppressed in other ways, such as chromatin remodeling and Piwi-mediated RNAi. Here, we discuss the mechanisms responsible for the transcriptionally silent state of PGCs in common experimental animals, such as Drosophila, C. elegans, Danio rerio, Xenopus, and mouse. While a PGC-specific downregulation of transcription is a common feature among these organisms, the diverse nature of underlying mechanisms suggests that this functional trait likely evolved independently on several instances. We discuss the possible biological relevance of these silencing mechanisms vis-a-vis fate determination of PGCs.
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Affiliation(s)
| | - Konstantin V. Yakovlev
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Laboratory of Cytotechnology, National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia
| | - Eugene N. Kozlov
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
| | - Paul Schedl
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- Department of Molecular Biology, Princeton University, Princeton, USA
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, USA
| | - Yulii V. Shidlovskii
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russia
- I.M. Sechenov First Moscow State Medical University, Moscow, Russia
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25
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Kistler KE, Trcek T, Hurd TR, Chen R, Liang FX, Sall J, Kato M, Lehmann R. Phase transitioned nuclear Oskar promotes cell division of Drosophila primordial germ cells. eLife 2018; 7:37949. [PMID: 30260314 PMCID: PMC6191285 DOI: 10.7554/elife.37949] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 09/09/2018] [Indexed: 12/25/2022] Open
Abstract
Germ granules are non-membranous ribonucleoprotein granules deemed the hubs for post-transcriptional gene regulation and functionally linked to germ cell fate across species. Little is known about the physical properties of germ granules and how these relate to germ cell function. Here we study two types of germ granules in the Drosophila embryo: cytoplasmic germ granules that instruct primordial germ cells (PGCs) formation and nuclear germ granules within early PGCs with unknown function. We show that cytoplasmic and nuclear germ granules are phase transitioned condensates nucleated by Oskar protein that display liquid as well as hydrogel-like properties. Focusing on nuclear granules, we find that Oskar drives their formation in heterologous cell systems. Multiple, independent Oskar protein domains synergize to promote granule phase separation. Deletion of Oskar’s nuclear localization sequence specifically ablates nuclear granules in cell systems. In the embryo, nuclear germ granules promote germ cell divisions thereby increasing PGC number for the next generation.
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Affiliation(s)
- Kathryn E Kistler
- Skirball Institute of Biomolecular Medicine, Howard Hughes Medical Institute, NYU School of Medicine, New York, United States.,Department of Molecular and Cellular Biology, University of Washington, Washington, United States
| | - Tatjana Trcek
- Skirball Institute of Biomolecular Medicine, Howard Hughes Medical Institute, NYU School of Medicine, New York, United States
| | - Thomas R Hurd
- Skirball Institute of Biomolecular Medicine, Howard Hughes Medical Institute, NYU School of Medicine, New York, United States.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Ruoyu Chen
- Skirball Institute of Biomolecular Medicine, Howard Hughes Medical Institute, NYU School of Medicine, New York, United States
| | - Feng-Xia Liang
- Department of Cell Biology, NYU School of Medicine, New York, United States.,DART Microscopy Laboratory, NYU Langone Health, New York, United States
| | - Joseph Sall
- DART Microscopy Laboratory, NYU Langone Health, New York, United States
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Texas, United States
| | - Ruth Lehmann
- Skirball Institute of Biomolecular Medicine, Howard Hughes Medical Institute, NYU School of Medicine, New York, United States.,Department of Cell Biology, NYU School of Medicine, New York, United States
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26
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Carrami EM, Eckermann KN, Ahmed HMM, Sánchez C HM, Dippel S, Marshall JM, Wimmer EA. Consequences of resistance evolution in a Cas9-based sex conversion-suppression gene drive for insect pest management. Proc Natl Acad Sci U S A 2018; 115:6189-6194. [PMID: 29844184 PMCID: PMC6004448 DOI: 10.1073/pnas.1713825115] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 08/07/2017] [Indexed: 11/18/2022] Open
Abstract
The use of a site-specific homing-based gene drive for insect pest control has long been discussed, but the easy design of such systems has become possible only with the recent establishment of CRISPR/Cas9 technology. In this respect, novel targets for insect pest management are provided by new discoveries regarding sex determination. Here, we present a model for a suppression gene drive designed to cause an all-male population collapse in an agricultural pest insect. To evaluate the molecular details of such a sex conversion-based suppression gene drive experimentally, we implemented this strategy in Drosophila melanogaster to serve as a safe model organism. We generated a Cas9-based homing gene-drive element targeting the transformer gene and showed its high efficiency for sex conversion from females to males. However, nonhomologous end joining increased the rate of mutagenesis at the target site, which resulted in the emergence of drive-resistant alleles and therefore curbed the gene drive. This confirms previous studies that simple homing CRISPR/Cas9 gene-drive designs will be ineffective. Nevertheless, by performing population dynamics simulations using the parameters we obtained in D. melanogaster and by adjusting the model for the agricultural pest Ceratitis capitata, we were able to identify adequate modifications that could be successfully applied for the management of wild Mediterranean fruit fly populations using our proposed sex conversion-based suppression gene-drive strategy.
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Affiliation(s)
- Eli M Carrami
- Department of Developmental Biology, Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Kolja N Eckermann
- Department of Developmental Biology, Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
- Molecular Cell Dynamics, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Hassan M M Ahmed
- Department of Developmental Biology, Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Héctor M Sánchez C
- Divisions of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
| | - Stefan Dippel
- Department of Developmental Biology, Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - John M Marshall
- Divisions of Epidemiology and Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
| | - Ernst A Wimmer
- Department of Developmental Biology, Johann Friedrich Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany;
- Göttingen Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
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27
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Control of Pem protein level by localized maternal factors for transcriptional regulation in the germline of the ascidian, Halocynthia roretzi. PLoS One 2018; 13:e0196500. [PMID: 29709000 PMCID: PMC5927453 DOI: 10.1371/journal.pone.0196500] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 04/13/2018] [Indexed: 12/04/2022] Open
Abstract
Localized maternal mRNAs play important roles in embryogenesis, e.g. the establishment of embryonic axes and the developmental cell fate specification, in various animal species. In ascidians, a group of maternal mRNAs, called postplasmic/PEM RNAs, is localized to a subcellular structure, called the Centrosome-Attracting Body (CAB), which contains the ascidian germ plasm, and is inherited by the germline cells during embryogenesis. Posterior end mark (Pem), a postplasmic/PEM RNAs member, represses somatic gene expression in the germline during cleavage stages by inhibition of RNA polymerase II activity. However, the functions of other postplasmic/ PEM RNAs members in germline formation are largely unknown. In this study, we analyzed the functions of two postplasmic/PEM RNAs, Popk-1 and Zf-1, in transcriptional regulation in the germline cells. We show that Popk-1 contributes to transcriptional quiescence by controlling the size of the CAB and amount of Pem protein translated at the CAB. Our studies also indicated that zygotic expression of a germline gene starts around the onset of gastrulation and that the decrease of Pem protein is necessary and sufficient for the zygotic germline gene expression. Finally, further studies showed that the decrease of the Pem protein level is facilitated by Zf-1. Taken together, we propose that postplasmic/PEM RNAs such as Popk-1 and Zf-1 control the protein level of the transcriptional repressor Pem and regulate its transcriptional state in the ascidian germline.
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28
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Sugimori S, Kumata Y, Kobayashi S. Maternal Nanos-Dependent RNA Stabilization in the Primordial Germ Cells of Drosophila Embryos. Dev Growth Differ 2017; 60:63-75. [PMID: 29278271 DOI: 10.1111/dgd.12414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/28/2017] [Accepted: 10/29/2017] [Indexed: 11/29/2022]
Abstract
Nanos (Nos) is an evolutionary conserved protein expressed in the germline of various animal species. In Drosophila, maternal Nos protein is essential for germline development. In the germline progenitors, or the primordial germ cells (PGCs), Nos binds to the 3' UTR of target mRNAs to repress their translation. In contrast to this prevailing role of Nos, here we report that the 3' UTR of CG32425 mRNA mediates Nos-dependent RNA stabilization in PGCs. We found that the level of mRNA expressed from a reporter gene fused to the CG32425 3' UTR was significantly reduced in PGCs lacking maternal Nos (nos PGCs) as compared with normal PGCs. By deleting the CG32425 3' UTR, we identified the region required for mRNA stabilization, which includes Nos-binding sites. In normal embryos, CG32425 mRNA was maternally supplied into PGCs and remained in this cell type during embryogenesis. However, as expected from our reporter assay, the levels of CG32425 mRNA and its protein product expressed in nos PGCs were lower than in normal PGCs. Thus, we propose that Nos protein has dual functions in translational repression and stabilization of specific RNAs to ensure proper germline development.
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Affiliation(s)
- Seiko Sugimori
- Life Science Center of Tsukuba Advanced Research Alliance (TARA Center), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan
| | - Yuji Kumata
- Developmental Genetics, National Institute for Basic Biology, Higashiyama, Okazaki, 444-8787, Japan
| | - Satoru Kobayashi
- Life Science Center of Tsukuba Advanced Research Alliance (TARA Center), University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
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29
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Flora P, Schowalter S, Wong-Deyrup S, DeGennaro M, Nasrallah MA, Rangan P. Transient transcriptional silencing alters the cell cycle to promote germline stem cell differentiation in Drosophila. Dev Biol 2017; 434:84-95. [PMID: 29198563 PMCID: PMC5830152 DOI: 10.1016/j.ydbio.2017.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 12/31/2022]
Abstract
Transcriptional silencing is a conserved process used by embryonic germ cells to repress somatic fate and maintain totipotency and immortality. In Drosophila, this transcriptional silencing is mediated by polar granule component (pgc). Here, we show that in the adult ovary, pgc is required for timely germline stem cell (GSC) differentiation. Pgc is expressed transiently in the immediate GSC daughter (pre-cystoblast), where it mediates a pulse of transcriptional silencing. This transcriptional silencing mediated by pgc indirectly promotes the accumulation of Cyclin B (CycB) and cell cycle progression into late-G2 phase, when the differentiation factor bag of marbles (bam) is expressed. Pgc mediated accumulation of CycB is also required for heterochromatin deposition, which protects the germ line genome against selfish DNA elements. Our results suggest that transient transcriptional silencing in the pre-cystoblast “re-programs” it away from self-renewal and toward the gamete differentiation program.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/The RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Sean Schowalter
- Department of Biological Sciences/The RNA Institute, University at Albany SUNY, Albany, NY 12222, USA; Boston University School of Medicine, 815 Albany Street, MA 02119, USA
| | - SiuWah Wong-Deyrup
- Department of Biological Sciences/The RNA Institute, University at Albany SUNY, Albany, NY 12222, USA
| | - Matthew DeGennaro
- Biomolecular Sciences Institute, Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Mohamad Ali Nasrallah
- Department of Biological Sciences/The RNA Institute, University at Albany SUNY, Albany, NY 12222, USA; University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Prashanth Rangan
- Department of Biological Sciences/The RNA Institute, University at Albany SUNY, Albany, NY 12222, USA.
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30
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The New RNA World: Growing Evidence for Long Noncoding RNA Functionality. Trends Genet 2017; 33:665-676. [DOI: 10.1016/j.tig.2017.08.002] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/01/2017] [Accepted: 08/02/2017] [Indexed: 12/18/2022]
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31
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Pae J, Cinalli RM, Marzio A, Pagano M, Lehmann R. GCL and CUL3 Control the Switch between Cell Lineages by Mediating Localized Degradation of an RTK. Dev Cell 2017; 42:130-142.e7. [PMID: 28743001 DOI: 10.1016/j.devcel.2017.06.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 05/15/2017] [Accepted: 06/27/2017] [Indexed: 11/29/2022]
Abstract
The separation of germline from somatic lineages is fundamental to reproduction and species preservation. Here, we show that Drosophila Germ cell-less (GCL) is a critical component in this process by acting as a switch that turns off a somatic lineage pathway. GCL, a conserved BTB (Broad-complex, Tramtrack, and Bric-a-brac) protein, is a substrate-specific adaptor for Cullin3-RING ubiquitin ligase complex (CRL3GCL). We show that CRL3GCL promotes PGC fate by mediating degradation of Torso, a receptor tyrosine kinase (RTK) and major determinant of somatic cell fate. This mode of RTK degradation does not depend upon receptor activation but is prompted by release of GCL from the nuclear envelope during mitosis. The cell-cycle-dependent change in GCL localization provides spatiotemporal specificity for RTK degradation and sequesters CRL3GCL to prevent it from participating in excessive activities. This precisely orchestrated mechanism of CRL3GCL function and regulation defines cell fate at the single-cell level.
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Affiliation(s)
- Juhee Pae
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Ryan M Cinalli
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Antonio Marzio
- HHMI, Department of Biochemistry and Molecular Pharmacology and Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Michele Pagano
- HHMI, Department of Biochemistry and Molecular Pharmacology and Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Ruth Lehmann
- HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA.
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32
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Zhang J, Liu W, Jin Y, Jia P, Jia K, Yi M. MiR-202-5p is a novel germ plasm-specific microRNA in zebrafish. Sci Rep 2017; 7:7055. [PMID: 28765643 PMCID: PMC5539161 DOI: 10.1038/s41598-017-07675-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 06/30/2017] [Indexed: 12/19/2022] Open
Abstract
Gametogenesis is a complicated biological process by which sperm and egg are produced for genetic transmission between generations. In many animals, the germline is segregated from the somatic lineage in early embryonic development through the specification of primordial germ cells (PGCs), the precursors of gametes for reproduction and fertility. In some species, such as fruit fly and zebrafish, PGCs are determined by the maternally provided germ plasm which contains various RNAs and proteins. Here, we identified a germ plasm/PGC-specific microRNA miR-202-5p for the first time in zebrafish. MiR-202-5p was specifically expressed in gonad. In female, it was expressed and accumulated in oocytes during oogenesis. Quantitative reverse transcription PCR and whole mount in situ hybridization results indicated that miR-202-5p exhibited a typical germ plasm /PGC-specific expression pattern throughout embryogenesis, which was consistent with that of the PGC marker vasa, indicating that miR-202-5p was a component of germ plasm and a potential PGC marker in zebrafish. Our present study might be served as a foundation for further investigating the regulative roles of miRNAs in germ plasm formation and PGC development in zebrafish and other teleost.
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Affiliation(s)
- Jing Zhang
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Wei Liu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Yilin Jin
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Peng Jia
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China
| | - Kuntong Jia
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China.
| | - Meisheng Yi
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangdong, China.
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33
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Abstract
A large body of evidence indicates that genome annotation pipelines have biased our view of coding sequences because they generally undersample small proteins and peptides. The recent development of genome-wide translation profiling reveals the prevalence of small/short open reading frames (smORFs or sORFs), which are scattered over all classes of transcripts, including both mRNAs and presumptive long noncoding RNAs. Proteomic approaches further confirm an unexpected variety of smORF-encoded peptides (SEPs), representing an overlooked reservoir of bioactive molecules. Indeed, functional studies in a broad range of species from yeast to humans demonstrate that SEPs can harbor key activities for the control of development, differentiation, and physiology. Here we summarize recent advances in the discovery and functional characterization of smORF/SEPs and discuss why these small players can no longer be ignored with regard to genome function.
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Affiliation(s)
- Serge Plaza
- Laboratoire de Recherches en Sciences Végétales, Université de Toulouse, Université Paul Sabatier, 31326 Castanet Tolosan, France; .,CNRS, UMR5546, Laboratoire de Recherches en Sciences Végétales, 31326 Castanet Tolosan, France
| | - Gerben Menschaert
- Department of Mathematical Modeling, Statistics and Bioinformatics, University of Ghent, 9000 Gent, Belgium
| | - François Payre
- Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, CNRS, Université Paul Sabatier, 31062 Toulouse, France;
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34
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Feng L, Shi Z, Chen X. Enhancer of polycomb coordinates multiple signaling pathways to promote both cyst and germline stem cell differentiation in the Drosophila adult testis. PLoS Genet 2017; 13:e1006571. [PMID: 28196077 PMCID: PMC5308785 DOI: 10.1371/journal.pgen.1006571] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022] Open
Abstract
Stem cells reside in a particular microenvironment known as a niche. The interaction between extrinsic cues originating from the niche and intrinsic factors in stem cells determines their identity and activity. Maintenance of stem cell identity and stem cell self-renewal are known to be controlled by chromatin factors. Herein, we use the Drosophila adult testis which has two adult stem cell lineages, the germline stem cell (GSC) lineage and the cyst stem cell (CySC) lineage, to study how chromatin factors regulate stem cell differentiation. We find that the chromatin factor Enhancer of Polycomb [E(Pc)] acts in the CySC lineage to negatively control transcription of genes associated with multiple signaling pathways, including JAK-STAT and EGF, to promote cellular differentiation in the CySC lineage. E(Pc) also has a non-cell-autonomous role in regulating GSC lineage differentiation. When E(Pc) is specifically inactivated in the CySC lineage, defects occur in both germ cell differentiation and maintenance of germline identity. Furthermore, compromising Tip60 histone acetyltransferase activity in the CySC lineage recapitulates loss-of-function phenotypes of E(Pc), suggesting that Tip60 and E(Pc) act together, consistent with published biochemical data. In summary, our results demonstrate that E(Pc) plays a central role in coordinating differentiation between the two adult stem cell lineages in Drosophila testes. Tissue maintenance and repair rely on adult stem cells, which can divide to generate new stem cells as well as cells committed for becoming specific cell types. Stem cell activity needs to be tightly controlled because insufficient or unlimited stem cell division may lead to tissue degeneration or tumorigenesis. This control depends not only on stem cells themselves, but also on the microenvironment where stem cells reside. The chromatin structure of stem cells is crucial to determine their activities. The signaling pathways connecting stem cells with their microenvironment is also important. Here we ask how chromatin factors interact with signaling pathways in determining stem cell activity. We use Drosophila adult testis as a model system, in which two types of stem cells co-exist and interact: germline stem cells and somatic stem cells. We find that a chromatin regulator called Enhancer of Polycomb [E(Pc)] acts in somatic cells to promote germ cell differentiation and maintain germ cell fate. This regulation is mediated by several signaling pathways, such as EGF and JAK-STAT pathways. E(Pc) also works with another chromatin regulator, the histone acetyltransferase Tip60, in somatic cells. Insufficient activity of the E(Pc) homolog in human leads to cancers. Our studies of E(Pc) may help understanding its roles as a tumor suppressor.
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Affiliation(s)
- Lijuan Feng
- Department of Biology, The Johns Hopkins University, Baltimore, MD, United States of America
| | - Zhen Shi
- Department of Biology, The Johns Hopkins University, Baltimore, MD, United States of America
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD, United States of America
- * E-mail:
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35
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Slaidina M, Lehmann R. Quantitative Differences in a Single Maternal Factor Determine Survival Probabilities among Drosophila Germ Cells. Curr Biol 2017; 27:291-297. [PMID: 28065608 DOI: 10.1016/j.cub.2016.11.048] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/24/2016] [Accepted: 11/23/2016] [Indexed: 11/26/2022]
Abstract
Germ cell death occurs in many species [1-3] and has been proposed as a mechanism by which the fittest, strongest, or least damaged germ cells are selected for transmission to the next generation. However, little is known about how the choice is made between germ cell survival and death. Here, we focus on the mechanisms that regulate germ cell survival during embryonic development in Drosophila. We find that the decision to die is a germ cell-intrinsic process linked to quantitative differences in germ plasm inheritance, such that higher germ plasm inheritance correlates with higher primordial germ cell (PGC) survival probability. We demonstrate that the maternal factor lipid phosphate phosphatase Wunen-2 (Wun2) regulates PGC survival in a dose-dependent manner. Since wun2 mRNA levels correlate with the levels of other maternal determinants at the single-cell level, we propose that Wun2 is used as a readout of the overall germ plasm quantity, such that only PGCs with the highest germ plasm quantity survive. Furthermore, we demonstrate that Wun2 and p53, another regulator of PGC survival, have opposite yet independent effects on PGC survival. Since p53 regulates cell death upon DNA damage and various cellular stresses, we hypothesize that together they ensure selection of the PGCs with highest germ plasm quantity and least cellular damage.
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Affiliation(s)
- Maija Slaidina
- Department of Cell Biology, Howard Hughes Medical Institute, and Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Ruth Lehmann
- Department of Cell Biology, Howard Hughes Medical Institute, and Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA.
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36
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Developmentally regulated long non-coding RNAs in Xenopus tropicalis. Dev Biol 2016; 426:401-408. [PMID: 27418388 PMCID: PMC5233649 DOI: 10.1016/j.ydbio.2016.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 06/10/2016] [Accepted: 06/11/2016] [Indexed: 01/24/2023]
Abstract
Advances in RNA sequencing technologies have led to the surprising discovery that a vast number of transcripts emanate from regions of the genome that are not part of coding genes. Although some of the smaller ncRNAs such as microRNAs have well-characterized functions, the majority of long ncRNA (lncRNA) functions remain poorly understood. Understanding the significance of lncRNAs is an important challenge facing biology today. A powerful approach to uncovering the function of lncRNAs is to explore temporal and spatial expression profiling. This may be particularly useful for classes of lncRNAs that have developmentally important roles as the expression of such lncRNAs will be expected to be both spatially and temporally regulated during development. Here, we take advantage of our ultra-high frequency (temporal) sampling of Xenopus embryos to analyze gene expression trajectories of lncRNA transcripts over the first 3 days of development. We computationally identify 5689 potential single- and multi-exon lncRNAs. These lncRNAs demonstrate clear dynamic expression patterns. A subset of them displays highly correlative temporal expression profiles with respect to those of the neighboring genes. We also identified spatially localized lncRNAs in the gastrula stage embryo. These results suggest that lncRNAs have regulatory roles during early embryonic development.
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Mainpal R, Yanowitz JL. A twist of fate: How a meiotic protein is providing new perspectives on germ cell development. WORM 2016; 5:e1175259. [PMID: 27383565 PMCID: PMC4911978 DOI: 10.1080/21624054.2016.1175259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 03/18/2016] [Accepted: 03/30/2016] [Indexed: 10/22/2022]
Abstract
The molecular pathways that govern how germ line fate is acquired is an area of intense investigation that has major implications for the development of assisted reproductive technologies, infertility interventions, and treatment of germ cell cancers. Transcriptional repression has emerged as a primary mechanism to ensure suppression of somatic growth programs in primordial germ cells. In this commentary, we address how xnd-1 illuminates our understanding of transcriptional repression and how it is coordinated with the germ cell differentiation program. We recently identified xnd-1 as a novel, early determinant of germ cell fates in Caenorhabditis elegans. Our study revealed that XND-1 is maternally deposited into early embryos where it is selectively enriched in the germ lineage and then exclusively found on chromatin in the germ lineage throughout development and into adulthood when it dissociates from chromosomes in late pachytene. This localization is consistent with a range of interesting germ cell defects that suggest xnd-1 is a pivotal determinant of germ cell characteristics. Loss of xnd-1 results in a unique "one PGC (primordial germ cell)" phenotype due to G2 cell cycle arrest of the germline precursor blastomere, P4, which predisposes the animal and its progeny for reduced fecundity. The sterility in xnd-1 mutants is correlated with an increase in the transcriptional activation-associated histone modification, dimethylation of histone H3 lysine 4 (H3K4me2), and aberrant expression of somatic transgenes but overlapping roles with nos-2 and nos-1 suggest that transcriptional repression is achieved by multiple redundant mechanisms.
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Affiliation(s)
- Rana Mainpal
- Department of Obstetrics, Magee-Womens Research Institute, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Judith L. Yanowitz
- Department of Obstetrics, Magee-Womens Research Institute, Gynecology and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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38
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Abstract
Germ granules are the hallmark of all germ cells. These membrane-less, electron-dense structures were first observed over 100 years ago. Today, their role in regulating and processing transcripts critical for the establishment, maintenance, and protection of germ cells is well established, and pathways outlining the biochemical mechanisms and physical properties associated with their biogenesis are emerging.
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Affiliation(s)
- Ruth Lehmann
- Howard Hughes Medical Institute (HHMI), Department of Cell Biology, Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, USA.
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Zanet J, Chanut-Delalande H, Plaza S, Payre F. Small Peptides as Newcomers in the Control of Drosophila Development. Curr Top Dev Biol 2016; 117:199-219. [PMID: 26969979 DOI: 10.1016/bs.ctdb.2015.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Throughout the last century, studies using the fruit fly have contributed to the discovery of many key genetic elements that control animal development. Recent work has shed light on an unexpectedly large number of RNAs that lack the classical hallmarks of protein-coding genes and are thus referred to as noncoding RNAs. However, there is mounting evidence that both mRNA and noncoding RNAs often contain small open reading frames (sORFs/smORFs), which can be translated into peptides. While genome-wide profiling supports a pervasive translation of these noncanonical sORF/smORF/SEP peptides, their functions remain poorly understood. Here, we review recent data obtained in Drosophila demonstrating the overlooked role of smORF peptides in the control of development and adult life. Focusing on a few smORF peptides whose functions have been elucidated recently, we discuss the importance of these newly identified regulatory molecules and how they act to regulate the building and function of the whole organism.
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Affiliation(s)
- J Zanet
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France
| | - H Chanut-Delalande
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France
| | - Serge Plaza
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France.
| | - Francios Payre
- Centre de Biologie du Développement, Université de Toulouse, UPS, Toulouse, France; Centre de Biologie du Développement, CNRS, UMR5547, Toulouse, France.
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40
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Abstract
Epigenetic mechanisms play an essential role in the germline and imprinting cycle. Germ cells show extensive epigenetic programming in preparation for the generation of the totipotent state, which in turn leads to the establishment of pluripotent cells in blastocysts. The latter are the cells from which pluripotent embryonic stem cells are derived and maintained in culture. Following blastocyst implantation, postimplantation epiblast cells develop, which give rise to all somatic cells as well as primordial germ cells, the precursors of sperm and eggs. Pluripotent stem cells in culture can be induced to undergo differentiation into somatic cells and germ cells in culture. Understanding the natural cycles of epigenetic reprogramming that occur in the germline will allow the generation of better and more versatile stem cells for both therapeutic and research purposes.
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Affiliation(s)
- Wolf Reik
- The Babraham Institute, Babraham Research Campus, Cambridge CB2 3EG, United Kingdom Wellcome Trust Cancer Research UK Gurdon Institute & Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - M Azim Surani
- Wellcome Trust Cancer Research UK Gurdon Institute & Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
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41
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Robert VJ, Garvis S, Palladino F. Repression of somatic cell fate in the germline. Cell Mol Life Sci 2015; 72:3599-620. [PMID: 26043973 PMCID: PMC11113910 DOI: 10.1007/s00018-015-1942-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/26/2015] [Accepted: 05/27/2015] [Indexed: 01/13/2023]
Abstract
Germ cells must transmit genetic information across generations, and produce gametes while also maintaining the potential to form all cell types after fertilization. Preventing the activation of somatic programs is, therefore, crucial to the maintenance of germ cell identity. Studies in Caenorhabditis elegans, Drosophila melanogaster, and mouse have revealed both similarities and differences in how somatic gene expression is repressed in germ cells, thereby preventing their conversion into somatic tissues. This review will focus on recent developments in our understanding of how global or gene-specific transcriptional repression, chromatin regulation, and translational repression operate in the germline to maintain germ cell identity and repress somatic differentiation programs.
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Affiliation(s)
- Valérie J Robert
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France
| | - Steve Garvis
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France
| | - Francesca Palladino
- Ecole Normale Supérieure de Lyon, Université de Lyon, 46 allée d'Italie, 69007, Lyon, France.
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42
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Abstract
Oskar (Osk) protein plays critical roles during Drosophila germ cell development, yet its functions in germ-line formation and body patterning remain poorly understood. This situation contrasts sharply with the vast knowledge about the function and mechanism of osk mRNA localization. Osk is predicted to have an N-terminal LOTUS domain (Osk-N), which has been suggested to bind RNA, and a C-terminal hydrolase-like domain (Osk-C) of unknown function. Here, we report the crystal structures of Osk-N and Osk-C. Osk-N shows a homodimer of winged-helix-fold modules, but without detectable RNA-binding activity. Osk-C has a lipase-fold structure but lacks critical catalytic residues at the putative active site. Surprisingly, we found that Osk-C binds the 3'UTRs of osk and nanos mRNA in vitro. Mutational studies identified a region of Osk-C important for mRNA binding. These results suggest possible functions of Osk in the regulation of stability, regulation of translation, and localization of relevant mRNAs through direct interaction with their 3'UTRs, and provide structural insights into a novel protein-RNA interaction motif involving a hydrolase-related domain.
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43
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Abstract
Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied 'germ plasm', inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells.
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Affiliation(s)
- Susan Strome
- Molecular, Cell &Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Dustin Updike
- Kathryn W. Davis Center for Regenerative Biology &Medicine, Mount Desert Island Biological Laboratory, Bar Harbor, Maine 04672, USA
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Laver JD, Marsolais AJ, Smibert CA, Lipshitz HD. Regulation and Function of Maternal Gene Products During the Maternal-to-Zygotic Transition in Drosophila. Curr Top Dev Biol 2015; 113:43-84. [PMID: 26358870 DOI: 10.1016/bs.ctdb.2015.06.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Drosophila late-stage oocytes and early embryos are transcriptionally silent. Thus, control of gene expression during these developmental periods is posttranscriptional and posttranslational. Global changes in the transcriptome and proteome occur during oocyte maturation, after egg activation and fertilization, and upon zygotic genome activation. We review the scale, content, and dynamics of these global changes; the factors that regulate these changes; and the mechanisms by which they are accomplished. We highlight the intimate relationship between the clearance of maternal gene products and the activation of the embryo's own genome, and discuss the fact that each of these complementary components of the maternal-to-zygotic transition can be subdivided into several phases that serve different biological roles and are regulated by distinct factors.
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Affiliation(s)
- John D Laver
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | | | - Craig A Smibert
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Howard D Lipshitz
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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Lee DM, Wilk R, Hu J, Krause HM, Harris TJC. Germ Cell Segregation from the Drosophila Soma Is Controlled by an Inhibitory Threshold Set by the Arf-GEF Steppke. Genetics 2015; 200:863-72. [PMID: 25971667 PMCID: PMC4512548 DOI: 10.1534/genetics.115.176867] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/10/2015] [Indexed: 12/11/2022] Open
Abstract
Germline cells segregate from the soma to maintain their totipotency, but the cellular mechanisms of this segregation are unclear. The Drosophila melanogaster embryo forms a posterior group of primordial germline cells (PGCs) by their division from the syncytial soma. Extended plasma membrane furrows enclose the PGCs in response to the germ plasm protein Germ cell-less (Gcl) and Rho1-actomyosin activity. Recently, we found that loss of the Arf-GEF Steppke (Step) leads to similar Rho1-dependent plasma membrane extensions but from pseudocleavage furrows of the soma. Here, we report that the loss of step also leads to premature formation of a large cell group at the anterior pole of the embryo . These anterior cells lacked germ plasm, but budded and formed at the same time as posterior PGCs, and then divided asynchronously as PGCs also do. With genetic analyses we found that Step normally activates Arf small G proteins and antagonizes Rho1-actomyosin pathways to inhibit anterior cell formation. A uniform distribution of step mRNA around the one-cell embryo cortex suggested that Step restricts cell formation through a global control mechanism. Thus, we examined the effect of Step on PGC formation at the posterior pole. Reducing Gcl or Rho1 levels decreased PGC numbers, but additional step RNAi restored their numbers. Reciprocally, GFP-Step overexpression induced dosage- and Arf-GEF-dependent loss of PGCs, an effect worsened by reducing Gcl or actomyosin pathway activity. We propose that a global distribution of Step normally sets an inhibitory threshold for Rho1 activity to restrict early cell formation to the posterior.
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Affiliation(s)
- Donghoon M Lee
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Ronit Wilk
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Jack Hu
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Henry M Krause
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
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Analysis of RNA Interference Lines Identifies New Functions of Maternally-Expressed Genes Involved in Embryonic Patterning in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2015; 5:1025-34. [PMID: 25834215 PMCID: PMC4478533 DOI: 10.1534/g3.115.017517] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Embryonic patterning in Drosophila melanogaster is initially established through the activity of a number of maternally expressed genes that are expressed during oogenesis. mRNAs from some of these genes accumulate in the posterior pole plasm of the oocyte and early embryo and localize further into RNA islands, which are transient ring-like structures that form around the nuclei of future primordial germ cells (pole cells) at stage 3 of embryogenesis. As mRNAs from several genes with known functions in anterior–posterior patterning and/or germ cell specification accumulate in RNA islands, we hypothesized that some other mRNAs that localize in this manner might also function in these developmental processes. To test this, we investigated the developmental functions of 51 genes whose mRNAs accumulate in RNA islands by abrogating their activity in the female germline using RNA interference. This analysis revealed requirements for ttk, pbl, Hip14, eIF5, eIF4G, and CG9977 for progression through early oogenesis. We observed dorsal appendage defects in a proportion of eggs produced by females expressing double-stranded RNA targeting Mkrn1 or jvl, implicating these two genes in dorsal–ventral patterning. In addition, posterior patterning defects and a reduction in pole cell number were seen in the progeny of Mkrn1 females. Because the mammalian ortholog of Mkrn1 acts as an E3 ubiquitin ligase, these results suggest an additional link between protein ubiquitination and pole plasm activity.
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47
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Martinho RG, Guilgur LG, Prudêncio P. How gene expression in fast-proliferating cells keeps pace. Bioessays 2015; 37:514-24. [PMID: 25823409 DOI: 10.1002/bies.201400195] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The development of living organisms requires a precise coordination of all basic cellular processes, in space and time. Early embryogenesis of most species with externally deposited eggs starts with a series of extremely fast cleavage cycles. These divisions have a strong influence on gene expression as mitosis represses transcription and pre-mRNA processing. In this review, we will describe the distinct adaptations for efficient gene expression and discuss the emerging role of the multifunctional NineTeen Complex (NTC) in gene expression and genomic stability during fast proliferation.
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Affiliation(s)
- Rui G Martinho
- Departamento de Ciências Biomédicas e Medicina, Regenerative Medicine Program, Universidade do Algarve, Campus de Gambelas, Faro, Portugal; Center for Biomedical Research, Universidade do Algarve, Campus de Gambelas, Faro, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal
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48
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Dahlberg O, Shilkova O, Tang M, Holmqvist PH, Mannervik M. P-TEFb, the super elongation complex and mediator regulate a subset of non-paused genes during early Drosophila embryo development. PLoS Genet 2015; 11:e1004971. [PMID: 25679530 PMCID: PMC4334199 DOI: 10.1371/journal.pgen.1004971] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 12/22/2014] [Indexed: 02/07/2023] Open
Abstract
Positive Transcription Elongation Factor b (P-TEFb) is a kinase consisting of Cdk9 and Cyclin T that releases RNA Polymerase II (Pol II) into active elongation. It can assemble into a larger Super Elongation Complex (SEC) consisting of additional elongation factors. Here, we use a miRNA-based approach to knock down the maternal contribution of P-TEFb and SEC components in early Drosophila embryos. P-TEFb or SEC depletion results in loss of cells from the embryo posterior and in cellularization defects. Interestingly, the expression of many patterning genes containing promoter-proximal paused Pol II is relatively normal in P-TEFb embryos. Instead, P-TEFb and SEC are required for expression of some non-paused, rapidly transcribed genes in pre-cellular embryos, including the cellularization gene Serendipity-α. We also demonstrate that another P-TEFb regulated gene, terminus, has an essential function in embryo development. Similar morphological and gene expression phenotypes were observed upon knock down of Mediator subunits, providing in vivo evidence that P-TEFb, the SEC and Mediator collaborate in transcription control. Surprisingly, P-TEFb depletion does not affect the ratio of Pol II at the promoter versus the 3’ end, despite affecting global Pol II Ser2 phosphorylation levels. Instead, Pol II occupancy is reduced at P-TEFb down-regulated genes. We conclude that a subset of non-paused, pre-cellular genes are among the most susceptible to reduced P-TEFb, SEC and Mediator levels in Drosophila embryos. Embryo development involves formation of various cell types through the regulation of gene transcription, resulting in expression of cell type specific RNAs and proteins. A key regulatory step in transcription of animal genes involves the transition of RNA polymerase II (Pol II) into active elongation. At many genes, Pol II is transiently paused approximately 50 basepairs downstream of the transcription start site. Release from this promoter-proximal pausing involves the kinase P-TEFb, which phosphorylates negative elongation factors, allowing Pol II to enter into productive elongation. In this work, we have depleted a considerable amount of P-TEFb from early Drosophila embryos. We find that several genes with paused Pol II can be expressed relatively normally in P-TEFb depleted embryos, whereas expression of some non-paused genes is substantially reduced. This result suggests that also non-paused genes transit through a P-TEFb-dependent checkpoint before entering active elongation. Unexpectedly, we find less Pol II associated with these non-paused genes in P-TEFb embryos. We demonstrate that a protein complex involved in recruitment of Pol II to promoters, the Mediator complex, show the same morphological and gene expression phenotypes as P-TEFb. We propose that Mediator and P-TEFb function together in recruiting Pol II to a subset of developmental genes.
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Affiliation(s)
- Olle Dahlberg
- Dept. Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Olga Shilkova
- Dept. Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Min Tang
- Dept. Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- Dept. Biochemistry & Biology, South China University, Hengyang, Hunan Province, China
| | - Per-Henrik Holmqvist
- Dept. Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Mattias Mannervik
- Dept. Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- * E-mail:
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49
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Santulli G. A Fleeting Glimpse Inside microRNA, Epigenetics, and Micropeptidomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 887:1-14. [PMID: 26662983 PMCID: PMC4871246 DOI: 10.1007/978-3-319-22380-3_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
MicroRNAs (miRs) are important regulators of gene expression in numerous biological processes. Their maturation process is herein described, including the most updated insights from the current literature. Circa 2000 miR sequences have been identified in the human genome, with over 50,000 miR-target interactions, including enzymes involved in epigenetic modulation of gene expression. Moreover, some "pieces of RNA" previously annotated as noncoding have been recently found to encode micropeptides that carry out critical mechanistic functions in the cell. Advanced techniques now available will certainly allow a precise scanning of the genome looking for micropeptides hidden within the "noncoding" RNA.
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50
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Abstract
Over the past decade there has been a greater understanding of genomic complexity in eukaryotes ushered in by the immense technological advances in high-throughput sequencing of DNA and its corresponding RNA transcripts. This has resulted in the realization that beyond protein-coding genes, there are a large number of transcripts that do not encode for proteins and, therefore, may perform their function through RNA sequences and/or through secondary and tertiary structural determinants. This review is focused on the latest findings on a class of noncoding RNAs that are relatively large (>200 nucleotides), display nuclear localization, and use different strategies to regulate transcription. These are exciting times for discovering the biological scope and the mechanism of action for these RNA molecules, which have roles in dosage compensation, imprinting, enhancer function, and transcriptional regulation, with a great impact on development and disease.
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Affiliation(s)
- Roberto Bonasio
- Department of Cell and Developmental Biology and Epigenetics Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104;
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