In Drosophila, reciprocal signals between germline and escort (in female) or somatic cyst (in male) cells can inhibit reversion to the stem cell state (Brawley and Matunis, 2004; Kai and Spradling, 2004) and restrict germ cell proliferation and cyst growth (Matunis et al, 1997). It has been proposed that escort stem cells. INTRODUCTION. In the germarium of the Drosophila ovary, developing germline cysts are surrounded by a population of somatic escort cells that are known to function as the niche cells for germline differentiation; 1 however, the underlying molecular mechanisms of this niche function remain poorly understood. Drosophila niche is composed of somatic terminal filament cells, cap cells and escort cells. The female and male GSC s can be reliably identified in vivo by their localization and by specific cellular markers, and remain accessible to sophisticated genetic manipulations. The core of the female GSC niche is a group of five to seven. Multiple tissue types are. The GSCs and cap cells also contact the Escort stem cells (blue). Drosophila female germline stem cells (GSCs) serve as one of the best understood stem cell types. Decapentaplegic (Dpp) is secreted from the germline stem cell (GSC) niche to activate Bone Morphogenic Protein (BMP) signaling in GSCs for their self-renewal and is restricted in the differentiation niche for daughter cell differentiation. Horne-Badovinac S, Bilder D. Drosophila melanogaster female GSCs have been utilized as a powerful model system to study the role of niche signals in the self-renewal and differentiation of stem cells, as it is relatively easy to anatomically visualize and genetically manipulate GSCs and their niche (Ables and. However, it remains largely unknown what constitutes a functional niche and how niche formation is controlled. elegans, and mouse, in the framework of important concepts in the adult stem cell biology. 10. Analysis of this niche established that the attachment between niche cells and stem cells was is important for stem cell maintenance but not for niche cell number or function [1,2]. However, separate signals appear to regulate escort stem cell and GSC. In Drosophila ovary. In the Drosophila ovary, germline stem cells (GSCs) in the niche continuously self-renew and generate differentiated germ cells that interact physically with escort cells (ECs). However, the underlying mechanism for the development of stem cell niche. Stem cell self-renewal is controlled by concerted actions of niche signals and intrinsic factors in a variety of systems. The astounding fecundity of Drosophila females that can lay dozens of eggs per day over several weeks depends on approximately 100 GSCs that are sustained by 40 stem cell niches. , 2011). Stem cell niches provide localized signaling molecules to promote stem cell fate and to suppress differentiation. Open 8. Stem cell self-renewal is controlled by concerted actions of extrinsic niche signals and intrinsic factors in a variety of systems. Using this Gal4 line, we could effectively induce FLP/FRT. Both escort cells and follicle cells interact dynamically with adjacent germ cells . In Drosophila ovary, niche is composed of somatic cells, including terminal filament cells (TFCs), cap cells (CCs) and escort cells (ECs), which provide extrinsic signals to maintain stem cell renewal or initiate cell differentiation. The niche for the germline stem cells (GSCs) in Drosophila serves as an important model for the analysis of interactions between niche and stem cells [1,3–5]. Figure 2. Natl. In the germarium of the Drosophila ovary, developing germline cysts are surrounded by a population of somatic escort cells that are known to function as the niche cells for germline differentiation; 1 however, the underlying molecular mechanisms of this niche function remain poorly understood. Lsd1 binds to fewer sites in cap cells. 2003; 100. Díaz-Torres et al. 1242/dev. CrossRef PubMed Central CAS PubMed Google Scholar Decotto E, Spradling AC (2005) The Drosophila ovarian and testis stem cell niches: similar somatic stem cells and signals. In niches that harbor multiple adjacent stem cells, such as those maintaining Drosophila germ cells, lost stem cells are replaced by division of neighboring stem cells or reversion of transit cells. Drosophila oogenesis depends on the presence of self-renewing GSCs in the adult ovary 1, 2. Although GSCs and FSCs are maintained within a distinct extra-cellular. The ovary contains at least two stem cell types, germline stem cells (GSCs) and somatic follicular stem cells (FSCs). Stem cells and their progenitors are maintained within a microenvironment, termed the niche, through local cell-cell communication. The loss of the JAK–STAT pathway in the germ line leads to a failure of stem cell maintenance and over-expression of the. Using Drosophila testis as a model. In this work, we demonstrate a powerful new tool for the manipulation of the stromal component of a well-established Drosophila stem cell niche. Therefore, the non-autonomous ecdysone effect can be explained. Crossref;. The GSC is surrounded by escort stem cells (ESCs) or cyst progenitor stem cells (CPCs) whose daughters (light blue) encyst the GSC daughter cell (pink). The niche is. The emerging niche is distinct from the adult because its main role is to support the progenitors that build organ systems in development. Kirilly D, Wang S, Xie T (2011) Self-maintained escort cells form a germline stem cell differentiation niche. find that “companion” hemocytes associate with the Drosophila female gonad to secrete CollIV present in the adult stem cell niche. Ovarian germline stem cells (GSCs) of Drosophila melanogaster provide a valuable in vivo model to investigate how the adult stem cell identity is maintained and the differentiation of the daughter cells is regulated. , 2004, Xie and Spradling, 1998). Our studies reveal that a previously unknown type of stem cell, escort stem cells, closely contacts the GSCs within the niche at the tip of each Drosophila ovariole. The niche region. Since GSCs are the fundamental cell population for successful reproduction, how such special GSCs are precisely proliferated is a long-standing question in biology. Morphogen-mediated signaling is critical for proper organ development and stem cell function, and well-characterized mechanisms spatiotemporally limit the expression of ligands, receptors, and ligand-binding cell-surface glypicans. Subsequently, follicle stem cells (FSCs) produce the many specialized follicle cells that cover each. Escort cells (yellow dashed line) signal to GSCs to promote differentiation. The terminal filament (TF), cap cells (CpCs), and anterior-most escort cells (ECs) form a GSC niche [5,6]. The piRNA (Piwi-interacting RNA) pathway, which represses transposable elements (TEs), is required in ECs to prevent the accumulation of undifferentiated germ cells (germline tumor phenotype). The stem cell niches play a pivotal role in guarding stem cells. Dyn. GSCs also respond to systemic signals, such as Drosophila insulin. This study reveals that various modes of Notch signaling activation induce the formation of the germline stem cell niche in Drosophila. Intestinal lining and blood cells are examples of cell types with high turnover produced by adult stem cells in humans. elegans and Drosophila stem cell niches (a) C. Here, we use the Drosophila germline stem cell (GSC) niche as a model system and show that GSCs signal to the niche through the Notch signaling pathway. raise the example of collaboration between stem cell types in the Drosophila ovary, where germline and escort stem cells mutually establish a niche for one another (Kirilly and Xie, 2007. The germarium houses three types of stem cells: GSCs, escort stem cells (ESCs), and somatic stem cells (SSCs) that produce follicle cells (see Table 1. In Drosophila, reciprocal signals between germline and escort (in female) or somatic cyst (in male) cells can inhibit reversion to the stem cell state (Brawley and Matunis, 2004; Kai and Spradling, 2004) and restrict germ cell proliferation and cyst growth (Matunis et al, 1997). Results reveal the importance of Perlecan for proper niche morphogenesis during pre-adult development and for tissue homeostasis in the adult. Niche establishment begins in larval stages when terminal filaments (TFs) are formed, but the underlying. In the Drosophila testis, Janus kinase–signal transducer and activator of transcription (JAK-STAT)This study used single-cell RNA-sequencing (scRNA-seq) to build a comprehensive cell atlas of the adult Drosophila ovary that contains transcriptional profiles for every major cell type in the ovary, including the germline stem cells and their niche cells, follicle stem cells, and previously undescribed subpopulations of escort cells. Drosophila is a highly tractable model for the study of these and other aspects of stem cell niches in vivo (Losick et al. Here we show that ECs, FSCs, and FCs develop from common pupal precursors, with different fates. This review will focus on the roles of JAK-STAT activity. The Drosophila testis stem cell niche consists of a cluster of non-mitotic somatic cells called the hub, which produces signals that maintain surrounding GSCs as well as cyst stem cells (CySCs). In Drosophila, germline stem cells (GSCs) are situated in a niche at the anterior end of the adult gonad while mature gametes are localized to the posterior, such that an anatomical axis of germ cell proliferation and differentiation is established in both sexes. At the apical tip of the ovary lie 12-16 germaria, each carrying two or three GSCs (Lin and Spradling, 1993; Spradling, 1993). Within the stem cell niche, several short-range extrinsic signals and intrinsic stemness-promoting factors are 39 crucial to maintain the GSCs self-renewal and differentiation. J. GSCs typically divide asymmetrically, giving rise to 1 daughter cell that retains its attachment to the hub and. Although niches can contain multiple types of stem cells, the coordinate regulation of stem cell behavior is poorly understood. Stem cells have the ability to self-renew and to produce specialized cells during development, normal organ function, and in response to tissue damage. Aberrant activation in hematopoietic stem cells is the underlying cause of a majority of myeloproliferative diseases. However, it remains unclear how these extrinsic signals are regulated. Drosophila GSCs are currently among the best-understood adult stem cells (1, 2). The Drosophila germline stem cell (GSC) niche includes terminal filament cells, cap cells, and escort stem cells, and GSC fate and activity require direct contact with cap cells and exposure to niche-derived signals (). While both contain germline stem cells, the testis niche also contains “cyst progenitor” stem cells, which divide to produce somatic cells that encase developing germ cells. Xing Ma. The stem cell niches at the apex of Drosophila ovaries and testes have been viewed as distinct in two major respects. The Wnt pathway limits BMP signaling outside of the germline stem cell niche in Drosophila ovaries. elegans germline stem cell ( GSC ) niche. The Drosophila ovary is recognized as a powerful model to study stem cell self-renewal and differentiation. The FSC is surrounded by FSC daugher cells (light blue) and also contacts the. Additionally, escort cells are not replenished by the regular division of escort stem cells as previously. As the Drosophila female ages, the stem cell niche undergoes age-dependent loss of GSC presence and activity. , McLeod C. The Drosophila ovary houses well-characterized germline stem cells and their niche, serving as an excellent model with which to study stem cell niche formation and maintenance. Similar to the male gonad, the ovary has a stem cell niche consisting of terminal filament cells (TFCs), somatic cap cells and escort stem cells (ESCs), located in the germarium. 1). Germline stem cell (GSC) self-renewal and differentiation into gametes is regulated by both intrinsic factors in the germ line as well as extrinsic factors from the surrounding somatic niche. Nature 454, 1132–1136 [PMC free article] [Google Scholar] Wang L. The Drosophila follicle cell stem cell (FSC) resides in an epidermal niche. Adult stem cells are maintained in specialized microenvironments called niches, which promote self-renewal and prevent differentiation. 2), and niche aging leads to stem cell decline (3–5). Germ cells are first wrapped by escort cells and then by follicle cells, which are derived from follicle stem cells (FSCs), to form egg chambers. Because GSCs can be easily identified and gene functions can be readily manipulated in Drosophila and C. Many of the mechanistic insights into how. Our lab uses Drosophila ovarian Follicle Stem Cells (FSCs) as a model system to perform in vivo experiments, in order to better understand adult stem cell behavior. Through single-cell gene expression profiling. The Drosophila melanogaster ovarian niche is established by several types of stromal cells, including terminal filament cells, cap cells, and escort cells (ECs). Studies in different stem. Results reveal the importance of Perlecan for proper niche morphogenesis during pre-adult development and for tissue homeostasis in the adult. Decapentaplegic (Dpp) is secreted from the germline stem cell (GSC) niche to activate Bone Morphogenic Protein (BMP) signaling in GSCs for their self-renewal and is restricted in the differentiation niche for daughter cell differentiation. In the germarium of the Drosophila ovary, developing germline cysts are surrounded by a population of somatic escort cells that are known to function as the. JAK-STAT signaling is a highly conserved regulator of stem cells and their niches. The Drosophila ovary harbors three different types of stem cell populations (germline stem cell (GSC), somatic stem cell (SSC) and escort stem cell (ESC)) located in a simple anatomical structure known as germarium, rendering it one of the best model systems for studying stem cell biology due to reliable stem cell identification and available. Further study into these relatively. Each testis. elegans and Drosophila stem cell niches ( a ) C. Oh Y. While both contain germline stem cells, the. However, the specific mechanisms by which niche support (or stromal) cells govern stem cell maintenance remain largely unknown. Adult stem cells reside in local microenvironments, or niches, in which signals from surrounding stromal cells inhibit differentiation (). The Drosophila melanogaster ovarian niche is established by several types of stromal cells, including terminal filament cells, cap cells, and escort cells (ECs). GSCs are adjacent to the somatic niche cells, which comprises cap cells, escort cells, and terminal filament cells (Figure 1A). Boyle, M. Drosophila ovarian germline stem cells (GSCs) have been one of the most productive systems for identifying the factors controlling self-renewal. View PDF View article View in Scopus Google Scholar. Adult stem cells have the ability to self-renew and give rise to differentiated cells in order to maintain tissue homoeostasis in multicellular organisms []. Niche is formed and recruits stem cells during tissue development; therefore, it. The mechanisms that modulate and limit the signaling output of adult stem cell niches remain poorly understood. The Drosophila male and female germ lines have served as ideal model systems for studying the regulation of stem cell behavior and asymmetric stem cell division controlled by the microenvironment or stem cell niche. , 2013. Moreover, while both niches utilize BMP signaling, the. 1242/dev. CySCs produce cyst cells that are required for. Biol. Indeed, the male and female germline stem cell (GSC) niches are particularly informative examples of a type of static niche, in which a dedicated population of niche cells produces a stable microenvironment that is necessary and. GSCs are embedded into a specialized cellular microenvironment, the so-called stem cell niche. The somatic niche cells surrounding the GSCs include terminal filament cells, cap cells and escort stem cells. B) The Drosophila follicle cell stem cell (FSC) is an example an epidermal niche. 2020. Through single-cell geneThe Drosophila ovary is regenerated from germline and somatic stem cell populations that have provided fundamental conceptual understanding on how adult stem cells are regulated within their niches. Aberrant activation in hematopoietic stem cells is the underlying cause of a majority of myeloproliferative diseases. In the second instar. Niches, rather than fixed cell lineages, ensure tissue health by holding stem cells and repressing cell differentiation inside, but not outside. In the Drosophila ovary, germline stem cells (GSCs) in the niche continuously self-renew and generate differentiated germ cells that interact physically with escort cells (ECs). It has been slightly more than 10 years since a stem cell niche was precisely documented using the Drosophila ovary (Xie and Spradling, 2000). (A) The adult ovary of Drosophila consists of 16–20 ovarioles, and the germarium of each ovariole has different types of cells. The GSC is surrounded by escort stem cells (ESC) or cyst progenitor stem cells (CPC) whose daughters (light blue) encyst the GSC daughter cell (pink). The Drosophila testis provides an excellent in vivo system to study stem cells’ niche interactions at the cellular and molecular levels [3, 11–33]. As a model of emerging niches, this review highlights how differences in the skeletal muscle. Adult stem cells, which are usually more restricted in their potency to produce different lineages, promise great therapeutic potential after initial clinical applications. The GFP channel and phalloidin channels are shown separately in B and C, respectively. In the Drosophila female germline stem cell (GSC) niche, Decapentaplegic (DPP) is an important niche factor for GSC self-renewal. Over the years, Drosophila has served as a wonderful genetically tractable model system to unravel various facets of tissue-resident stem cells in their microenvironment. (2007). extrinsic signals from surrounding stromal cells or niche. The piRNA (Piwi-interacting RNA) pathway, which represses transposable elements (TEs), is required in ECs to prevent the accumulation of undifferentiated germ cells (germline tumor phenotype). It has been proposed that escort stem cells. We. Stem cells and their progenitors are maintained within a microenvironment, termed the niche, through local cell-cell communication. Drosophila germ cells in both sexes initially follow a similar pathway. Cap cells (green) and escort stem cells (purple) function as a niche to maintain GSCs (red, green shade representing the niche influence), allowing germ cells (pink) outside the niche to differentiate. Drosophila female (A) and male (B) germ line stem cells and their niche. The core of the female GSC niche is a group of five to seven nondividing somatic cap cells that physically anchor two or three GSCs to the anterior of each germarium ( 60 – 62 ). A Human hematopoietic SCN: This is one of the best-characterized niches, with the hematopoietic stem cells (HSCs) receiving systemic and local signals. Biol. These stem cells are the progenitors of the follicular epithelium that surrounds the germline cysts in most of the. However, the underlying mechanism for the development of stem cell niche remains largely unclear. In summary, our results uncover the molecular mechanism by which systemic and niche-local signals are integrated in the stem cell niche. Escort stem cells (ESCs, female) and cyst progenitor cells (CPCs, male) also provide environments that maintain GSC identityStem cells reside in specialized microenvironments or niches that balance stem cell proliferation and differ- entiation. 7. identify the ECM molecule Perlecan as an essential component of the ovarian niche in Drosophila. The Hub: Stem Cell Meeting Point in the Drosophila Testis. In the germarium of the Drosophila ovary, developing germline cysts are surrounded by a population of somatic escort cells that are known to function as the niche cells for germline. To gain further insights into how these microenvironments are regulated in vivo, we performed a candidate gene screen designed to identify factors that restrict BMP signal production to the cap cells that comprise the. The niche is. We have generated a bric-a-brac 1 (bab1)-Gal4 line that drives UAS expression in many somatic ovary cell types from early larval stages. Escort stem cells correspond to somatic cyst stem cells (Fuller and Spradling, 2007; Kahney et al. In the germarium of the Drosophila ovary, 2 to 3 germline stem cellsresideattheanteriortip,nexttoaclusterofcapcells. Decapentaplegic (Dpp) is required to maintain the anterior stem cells, whereas. Escort cells and follicle cells often displayed clear cytoplasms,. Germline stem cells (GSCs) can generate haploid gametes, sperms or oocyte, which are responsible for transmitting genetic information from generation to generation. The somatic terminal filament cells and cap cells at the anterior of the germarium, as well as somatic escort cells located posteriorly to cap cells, act as niche for adjacent or nearby GSCs, GSCs physically associated with cap cells anteriorly and escort cells laterally [1,7].