The germinal proliferation center in the testis of Drosophila melanogaster

Hardy, Robert W.; Tokuyasu, K. T.; Lindsley, Dan L.; Garavito, M.

doi:10.1016/s0022-5320(79)90108-4

Cited by 279 publications

(298 citation statements)

References 13 publications

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“…Normally, five to nine GSCs are attached to a cluster of somatic hub cells in the apex of the testis (Fig. 1 A) (17). Hub cells provide a microenvironment, or ''niche,'' for the GSCs (10,11), which divide radially to ensure that one daughter cell remains at the hub and retains stem cell identity, whereas the displaced daughter cell differentiates into a gonialblast ( Fig.…”

Section: Results and Discussion Loss Of Msi Function Results In The Lmentioning

confidence: 99%

The RNA-binding protein Musashi is required intrinsically to maintain stem cell identity

Siddall

McLaughlin²,

Marriner

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

109

134

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A key goal of regenerative medicine is an understanding of the genetic factors that define the properties of stem cells. However, stem cell research in mammalian tissue has been hampered by a paucity of stem cell-specific markers. Although increasing evidence suggests that members of the Musashi (Msi) family of RNA-binding proteins play important functions in progenitor cells, it remains unclear whether there is a stem cell-autonomous requirement for Msi because of an inability to distinguish stem cells from earlylineage cells in mammalian tissues. Here, using the Drosophila testis as a model system for the study of stem cell regulation, we show specific evidence for a cell-autonomous requirement for Msi family proteins in regulating stem cell differentiation, leading to the identification of an RNA-binding protein required for spermatogonial stem cell maintenance. We found that loss of Msi function disrupts the balance between germ-line stem cell renewal and differentiation, resulting in the premature differentiation of germ-line stem cells. Moreover, we found that, although Msi is expressed in both somatic and germ cells, Msi function is required intrinsically in stem cells for maintenance of stem cell identity. We also discovered a requirement for Msi function in male meiosis, revealing that Msi has distinct roles at different stages of germ cell differentiation. We describe the complementary expression patterns of the murine Msi paralogues Msi1 and Msi2 during spermatogenesis, which support the idea of distinct, evolutionarily conserved roles of Msi.spermatogenesis ͉ Drosophila ͉ testis ͉ spermatocyte ͉ translation

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Section: Results and Discussion Loss Of Msi Function Results In The Lmentioning

confidence: 99%

The RNA-binding protein Musashi is required intrinsically to maintain stem cell identity

Siddall

McLaughlin²,

Marriner

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

109

134

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“…The embryonic male stem cell niche closely resembles that of the adult male: a tight cluster of SGPs that express esg-LacZ, Fas3, and the Jak-Stat ligand Unpaired, which is associated with a group of anterior PGCs in the same rosette pattern as that observed in the adult (81,88). The restriction of hub cell fate and the rosette pattern of PGCs around the hub suggest that a functional GSC niche forms in male embryos, much earlier than niche development in the female.…”

Section: And Ref 83)mentioning

confidence: 88%

The Development of Germline Stem Cells in Drosophila

Dansereau

Lasko

2008

Methods in Molecular Biology™

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SummaryGermline 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). Shortrange 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. KeywordsDrosophila; germline stem cell; GSC; PGC; primordial germ cell; stem cell fate; stem cell niche IntroductionStem cells are defined by their capacity to self-renew and to generate daughters that differentiate into one or more terminal cell types. Proper regulation of this property is critical for animal development, growth control, and reproduction. Understanding stem cell function is potentially very important for future developments in gene therapies and regenerative medicine. Research in Drosophila on germline stem cells (GSCs) has been instrumental in defining the important function of the stem cell's somatic microenvironment or niche in the control of its division and self-renewal (1,2). The Drosophila germline is an excellent model of stem cell biology because the system is genetically tractable, the sterility and rudimentary gonads resulting from GSC loss are easily recognized, and the stem cells can be easily identified based on molecular markers and position in the gonad. Germline morphology and development, from embryogenesis to the differentiation of gametes in adult flies, has been well characterized and offers a solid basis for the study of GSC fate determination, maintenance, and differentiation.Drosophila GSCs are derived from embryonic pole cells, the first cell type defined in the embryo. They migrate from the posterior to meet the somatic gonadal precursors (SGPs) and form the embryonic gonad, a simple structure made up of about ten primordial germ cells (PGCs) intermingled with and surr...

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“…2 C and D), a GSC characteristic that programs spindle orientation and the asymmetric outcome of stem cell division (8,17). When the duplicated centrosomes separate in the G 2 phase of the cell cycle in wild-type Drosophila male GSCs, one normally remains near the GSC-hub interface, whereas the other migrates to the opposite side of the cell (8,18).…”

Section: Collar Germ Cells Maintained Next To the Hub In The Absence mentioning

confidence: 99%

Somatic cell lineage is required for differentiation and not maintenance of germline stem cells in Drosophila testes

Lim

Fuller

2012

Proc. Natl. Acad. Sci. U.S.A.

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Adult stem cells are believed to be maintained by a specialized microenvironment, the niche, which provides short-range signals that either instruct stem cells to self-renew or inhibit execution of preprogrammed differentiation pathways. In Drosophila testes, somatic cyst stem cells (CySCs) and the apical hub form the niche for neighboring germline stem cells (GSCs), with CySCs as the proposed source of instructive self-renewal signals [Leatherman JL, Dinardo S (2010) Nat Cell Biol 12(8):806-811]. In contrast to this model, we show that early germ cells with GSC characteristics can be maintained over time after ablation of CySCs and their cyst cell progeny. Without CySCs and cyst cells, early germ cells away from the hub failed to initiate differentiation. Our results suggest that CySCs do not have a necessary instructive role in specifying GSC self-renewal and that the differentiated progeny of CySCs provide an environment necessary to trigger GSC differentiation. This work highlights the complex interaction between different stem cell populations in the same niche and how the state of one stem cell population can influence the fate of the other.

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The germinal proliferation center in the testis of Drosophila melanogaster

Cited by 279 publications

References 13 publications

The RNA-binding protein Musashi is required intrinsically to maintain stem cell identity

The RNA-binding protein Musashi is required intrinsically to maintain stem cell identity

The Development of Germline Stem Cells in Drosophila

Somatic cell lineage is required for differentiation and not maintenance of germline stem cells in Drosophila testes

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