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Tiwari MD, Zeitler DM, Meister G, Wodarz A. Molecular profiling of stem cell-like female germ line cells in Drosophila delineates networks important for stemness and differentiation. Biol Open 2019; 8:bio.046789. [PMID: 31649115 PMCID: PMC6899027 DOI: 10.1242/bio.046789] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Stem cells can self-renew and produce daughter cells destined for differentiation. The precise control of the balance between these two outcomes is essential to ensure tissue homeostasis and to prevent uncontrolled proliferation resulting in tumor formation. As self-renewal and differentiation are likely to be controlled by different gene expression programs, unraveling the underlying gene regulatory networks is crucial for understanding the molecular logic of this system. In this study, we have characterized by next generation RNA sequencing (RNA-seq) the transcriptome of germline stem cell (GSC)-like cells isolated from bag of marbles (bam) mutant Drosophila ovaries and compared it to the transcriptome of germ line cells isolated from wild-type ovaries. We have complemented this dataset by utilizing an RNA-immunoprecipitation strategy to identify transcripts bound to the master differentiation factor Bam. Protein complex enrichment analysis on these combined datasets allows us to delineate known and novel networks essential for GSC maintenance and differentiation. Further comparative transcriptomics illustrates similarities between GSCs and primordial germ cells and provides a molecular footprint of the stem cell state. Our study represents a useful resource for functional studies on stem cell maintenance and differentiation. Summary: Fruit fly germline stem cell differentiation is accompanied by major changes of the transcriptome that may be regulated at the post-transcriptional level.
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Affiliation(s)
- Manu D Tiwari
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Kerpener Str. 62, 50937 Köln, Germany .,Cluster of Excellence - Cellular stress response in aging-associated diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.,Stem Cell Biology, Institute for Anatomy and Cell Biology, Georg-August University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
| | - Daniela M Zeitler
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
| | - Gunter Meister
- Regensburg Center for Biochemistry (RCB), University of Regensburg, Universitätsstr. 31, 93053 Regensburg, Germany
| | - Andreas Wodarz
- Molecular Cell Biology, Institute I for Anatomy, University of Cologne Medical School, Kerpener Str. 62, 50937 Köln, Germany .,Cluster of Excellence - Cellular stress response in aging-associated diseases (CECAD), University of Cologne, Joseph-Stelzmann-Str. 26, 50931 Cologne, Germany.,Stem Cell Biology, Institute for Anatomy and Cell Biology, Georg-August University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Robert-Koch-Str. 21, 50931 Cologne, Germany
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Abstract
Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision.
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Affiliation(s)
- Maija Slaidina
- Howard Hughes Medical Institute 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 Howard Hughes Medical Institute 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
| | - Ruth Lehmann
- Howard Hughes Medical Institute 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 Howard Hughes Medical Institute 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
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Functional analysis of the Drosophila embryonic germ cell transcriptome by RNA interference. PLoS One 2014; 9:e98579. [PMID: 24896584 PMCID: PMC4045815 DOI: 10.1371/journal.pone.0098579] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/05/2014] [Indexed: 11/19/2022] Open
Abstract
In Drosophila melanogaster, primordial germ cells are specified at the posterior pole of the very early embryo. This process is regulated by the posterior localized germ plasm that contains a large number of RNAs of maternal origin. Transcription in the primordial germ cells is actively down-regulated until germ cell fate is established. Bulk expression of the zygotic genes commences concomitantly with the degradation of the maternal transcripts. Thus, during embryogenesis, maternally provided and zygotically transcribed mRNAs determine germ cell development collectively. In an effort to identify novel genes involved in the regulation of germ cell behavior, we carried out a large-scale RNAi screen targeting both maternal and zygotic components of the embryonic germ line transcriptome. We identified 48 genes necessary for distinct stages in germ cell development. We found pebble and fascetto to be essential for germ cell migration and germ cell division, respectively. Our data uncover a previously unanticipated role of mei-P26 in maintenance of embryonic germ cell fate. We also performed systematic co-RNAi experiments, through which we found a low rate of functional redundancy among homologous gene pairs. As our data indicate a high degree of evolutionary conservation in genetic regulation of germ cell development, they are likely to provide valuable insights into the biology of the germ line in general.
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Abstract
This unit describes how to collect, culture, and establish stable cell lines of ovarian somatic and germline stem cells of Drosophila. We also describe a protocol for culturing embryonic cells that overexpress growth factors, which serve as a source for conditioned medium.
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Abstract
Germline stem cells (GSCs) in Drosophila are a valuable model to explore of how adult stem cells are regulated in vivo. Genetic dissection of this system has shown that stem cell fate is determined and maintained by the stem cell's somatic microenvironment or niche. In Drosophila gonads, the stem cell niche -- the cap cell cluster in females and the hub in males -- acts as a signaling center to recruit GSCs from among a small population of undifferentiated primordial germ cells (PGCs). Short-range signals from the niche specify and regulate stem cell fate by maintaining the undifferentiated state of the PGCs next to the niche. Germline cells that do not receive the niche signals because of their location assume the default fate and differentiate. Once GSCs are specified, adherens junctions maintain close association between the stem cells and their niche and help to orient stem cell division so that one daughter is displaced from the niche and differentiates. In females, stem cell fate depends on bone morphogenetic protein (BMP) signals from the cap cells; in males, hub cells express the cytokine-like ligand Unpaired, which activates the Janus kinase-signal transducers and activators of transcription (Jak-Stat) pathway in stem cells. Although the signaling pathways operating between the niche and stem cells are different, there are common general features in both males and females, including the arrangement of cell types, many of the genes used, and the logic of the system that maintains stem cell fate.
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Niki Y, Yamaguchi T, Mahowald AP. Establishment of stable cell lines of Drosophila germ-line stem cells. Proc Natl Acad Sci U S A 2006; 103:16325-30. [PMID: 17056713 PMCID: PMC1637581 DOI: 10.1073/pnas.0607435103] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Each Drosophila ovariole has three independent sets of stem cells: germ-line stem cells (GSCs) and escort stem cells, located at the anterior tip of the germarium, and somatic stem cells (SSCs), located adjacent to the newly formed 16-cell cysts. Decapentaplegic (Dpp) is required to maintain the anterior stem cells, whereas Hedgehog is required for maintenance and cell division of the SCCs. In an effort to establish a new in vitro system to analyze intrinsic and extrinsic factors regulating the division and differentiation of GSCs of Drosophila, we tested various culture conditions for growing GSCs, derived from bag of marbles (bam) mutant ovaries. We have shown that bam(-) GSCs can be maintained and promoted to divide in vitro in media containing Dpp. These cells retain the morphological features of GSCs, i.e., expression of Vasa and Nanos and spectrosomes, even after several months of culture. Somatic cells are induced to grow in culture by the presence of sonic Hedgehog. The somatic cells produce Dpp. GSCs associate with the somatic cells via DE-cadherin, features that are also prominent at the niche of a normal germarium. Finally, we have established stable cell cultures consisting of GSCs and sheets of somatic cells, which are dependent on the addition of fly extract. A somatic cell line, lacking GSCs, has also been established. These cells are thought to be descendants of SCCs. Our in vitro system may provide the opportunity to manipulate GSCs genetically and to analyze the interaction of germ-line stem cells and soma.
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Affiliation(s)
- Yuzo Niki
- *Department of Sciences, Faculty of Science, Ibaraki University, Mito 310-8512, Japan; and
- To whom correspondence may be addressed. E-mail:
or
| | - Takafumi Yamaguchi
- *Department of Sciences, Faculty of Science, Ibaraki University, Mito 310-8512, Japan; and
| | - Anthony P. Mahowald
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637
- To whom correspondence may be addressed. E-mail:
or
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Kai T, Williams D, Spradling AC. The expression profile of purified Drosophila germline stem cells. Dev Biol 2005; 283:486-502. [PMID: 15927177 DOI: 10.1016/j.ydbio.2005.04.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 04/12/2005] [Accepted: 04/13/2005] [Indexed: 12/12/2022]
Abstract
We developed a method to highly purify germline stem cells (GSCs) from the Drosophila ovary, one of the best understood types of adult stem cell. GSCs express variant isoforms of general transcriptional components, translation initiation factors, and several variant ribosomal proteins, including RpL22, a protein enriched in several mammalian stem cells. These novel isoforms may help regulate stem cell gene expression because a reversion assay indicated that at least four were specific for GSCs. By comparative analysis, we identify additional genes enriched in GSCs, including Psc, the Drosophila homolog of the Bmi-1 Polycomb group gene, as well as genes that may delay cytokinesis in pre-meiotic germ cells. By comparing GSCs arrested by BMP over-expression and bam mutation, we hypothesize that mRNA utilization is modulated in differentiating GSC daughters. Our findings suggest that Drosophila and mammalian stem cells utilize at least two regulatory mechanisms in common.
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Affiliation(s)
- Toshie Kai
- Howard Hughes Medical Institute Research Laboratories, Department of Embryology, Carnegie Institution, Baltimore, MD 21210, USA
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Schwartsburd PM. Age-promoted creation of a pro-cancer microenvironment by inflammation: pathogenesis of dyscoordinated feedback control. Mech Ageing Dev 2005; 125:581-90. [PMID: 15491675 DOI: 10.1016/j.mad.2004.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 07/16/2004] [Accepted: 08/10/2004] [Indexed: 11/19/2022]
Abstract
Aging and local chronic inflammation are established risk factors for epithelial tumorigenesis. These risk factors can act individually and/or synergistically to increase the incidence of age-related carcinomas. The basis for this co-stimulatory response has not yet been defined, nor have the feedback mechanisms that are responsible for this synergism. This review provides insight into the age-stimulated dysregulation of coordination of feedbacks in oxygen-, heme-, and proteolysis-dependent metabolic pathways caused by acute and chronic inflammation, and its role as a possible pathological basis for the creation of a pro-cancer microenvironment (PCM). The PCM facilitates the selective survival and growth of transformed cells (in a manner similar to a cancer-supportive microenvironment (CM)). The cancer-induced environment has certain features in common with chronic inflammatory-induced PCM. Namely, there are: enhanced oxidative cell resistance against apoptosis, increased production of matrix-degrading enzymes, switching to glycolytic metabolism, angiogenesis and vasorelaxation thus providing nutrient delivery, but restriction of the immune cell mobilization and/or its activation. The hypothetical model of PCM-genesis is presented as a result of enzymatic dysregulation of feedback control including oxygen-, heme-, prostaglandin E(2)-, metalloproteinase-9-, and NO/CO-dependent pathways. PCM-genesis takes place between the growth-inhibiting (cytotoxic) and growth promoting (regenerative) stages of inflammatory response. According to this model, age-related metabolic changes create opportunities for chronic (not acute) inflammatory response, which supports the PCM-condition with the non-healing wound state that often occurs around carcinomas.
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Affiliation(s)
- P M Schwartsburd
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region.
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Gilboa L, Lehmann R. How different is Venus from Mars? The genetics of germ-line stem cells inDrosophilafemales and males. Development 2004; 131:4895-905. [PMID: 15459096 DOI: 10.1242/dev.01373] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the fruit fly Drosophila melanogaster, both spermatogenesis and oogenesis rely on germ-line stem cells (GSCs). Intensive research has revealed many of the molecules and pathways that underlie GSC maintenance and differentiation in males and females. In this review, we discuss new studies that, some differences notwithstanding, highlight the similarities in the structural and molecular strategies used by the two sexes in GSC maintenance and differentiation. These include the tight control that somatic support cells exert on every aspect of GSC function and the similar molecular mechanisms for physical attachment, cell-cell signaling and gap-junction communication. Some common principles underlying GSC biology in the fly may be applied to stem cells in other organisms.
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Affiliation(s)
- Lilach Gilboa
- Developmental Genetics Program, Skirball Institute and Department of Cell Biology at NYU School of Medicine and Howard Hughes Medical Institute, 540 First Avenue, New York, NY 10016, USA
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Abstract
The passage of an individual's genome to future generations is essential for the maintenance of species and is mediated by highly specialized cells, the germ cells. Genetic studies in a number of model organisms have provided insight into the molecular mechanisms that control specification, migration and survival of early germ cells. Focusing on Drosophila, we will discuss the mechanisms by which germ cells initially form and remain transcriptionally silent while somatic cells are transcriptionally active. We will further discuss three separate attractive and repellent guidance pathways, mediated by a G-protein coupled receptor, two lipid phosphate phosphohydrolases, and isoprenylation. We will compare and contrast these findings with those obtained in other organisms, in particular zebrafish and mice. While aspects of germ cell specification are strikingly different between these species, germ cell specific gene functions have been conserved. In particular, mechanisms that sense directional cues during germ cell migration seem to be shared between invertebrates and vertebrates.
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Affiliation(s)
- Ana C Santos
- Howard Hughes Medical Institute, Developmental Genetics Program, Skirball Institute and Department of Cell Biology at NYU School of Medicine, 540 First Avenue, New York, New York 10016, USA
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