Somatic signaling mediated by fs(1)Yb is essential for germline stem cell maintenance during Drosophila oogenesis

Drosophila oogenesis starts when a germline stem cell divides asymmetrically to generate a daughter germline stem cell and a cystoblast that will develop into a mature egg. We show that the fs(1)Yb gene is essential for the maintenance of germline stem cells during oogenesis. We delineate fs(1)Yb within a 6.4 kb genomic region by transgenic rescue experiments. fs(1)Yb encodes a 4.1 kb RNA that is present in the third instar larval, pupal and adult stages, consistent with its role in regulating germline stem cells during oogenesis. Germline clonal analysis shows that all fs(1)Yb mutations are soma-dependent. In the adult ovary, fs(1)Yb is specifically expressed in the terminal filament cells, suggesting that fs(1)Yb acts in these signaling cells to maintain germline stem cells. fs(1)Yb encodes a novel hydrophilic protein with no potential signal peptide or transmembrane domains, suggesting that this protein is not itself a signal but a key component of the signaling machinery for germline stem cell maintenance.

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Niche maintenance of germline stem cells in C. elegans males

10.1101/428235 ◽

2018 ◽

Author(s):

Sarah L. Crittenden ◽

ChangHwan Lee ◽

Ipsita Mohanty ◽

Sindhu Battula ◽

Judith Kimble

Keyword(s):

Stem Cell ◽

Cell Number ◽

Germline Stem Cell ◽

Sexually Dimorphic ◽

Common Theme ◽

Germline Stem Cells ◽

Cellular Behavior ◽

C Elegans ◽

Stem Cell Maintenance ◽

Cell Maintenance

ABSTRACTStem cell maintenance by niche signaling is a common theme across phylogeny. In the Caenorhabditis elegans gonad, the broad outlines of germline stem cell (GSC) regulation are the same for both sexes: GLP-1/Notch signaling from the mesenchymal Distal Tip Cell (DTC) niche maintains GSCs in the distal gonad of both sexes (Austin and Kimble 1987), and does so via two key stem cell regulators, SYGL-1 and LST-1 (Kershneret al. 2014). Most analyses of niche signaling and GSC regulation have focused on XX hermaphrodites, an essentially female sex making sperm in larvae and oocytes in adults. Here we focus on XO males, which are sexually dimorphic in all tissues, including the distal gonad. The architecture of the male niche and the cellular behavior of GSCs are sex-specific. Despite these differences, males maintain a GSC pool similar to the hermaphrodite with respect to size and cell number and the male GSC response to niche signaling is also remarkably similar.

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Cell-cycle quiescence maintains Caenorhabditis elegans germline stem cells independent of GLP-1/Notch

eLife ◽

10.7554/elife.10832 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 44

Author(s):

Hannah S Seidel ◽

Judith Kimble

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Stem Cell ◽

Caenorhabditis Elegans ◽

Signaling Pathway ◽

Adult Stem Cells ◽

Germline Stem Cells ◽

Stem Cell Maintenance ◽

M Phase ◽

Cell Maintenance

Many types of adult stem cells exist in a state of cell-cycle quiescence, yet it has remained unclear whether quiescence plays a role in maintaining the stem cell fate. Here we establish the adult germline of Caenorhabditis elegans as a model for facultative stem cell quiescence. We find that mitotically dividing germ cells—including germline stem cells—become quiescent in the absence of food. This quiescence is characterized by a slowing of S phase, a block to M-phase entry, and the ability to re-enter M phase rapidly in response to re-feeding. Further, we demonstrate that cell-cycle quiescence alters the genetic requirements for stem cell maintenance: The signaling pathway required for stem cell maintenance under fed conditions—GLP-1/Notch signaling—becomes dispensable under conditions of quiescence. Thus, cell-cycle quiescence can itself maintain stem cells, independent of the signaling pathway otherwise essential for such maintenance.

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The actin-binding protein profilin is required for germline stem cell maintenance and germ cell enclosure by somatic cyst cells

Development ◽

10.1242/dev.101931 ◽

2013 ◽

Vol 141 (1) ◽

pp. 73-82 ◽

Cited By ~ 24

Author(s):

A. R. Shields ◽

A. C. Spence ◽

Y. M. Yamashita ◽

E. L. Davies ◽

M. T. Fuller

Keyword(s):

Stem Cell ◽

Germ Cell ◽

Binding Protein ◽

Actin Binding ◽

Germline Stem Cell ◽

Actin Binding Protein ◽

Stem Cell Maintenance ◽

Cyst Cells ◽

Cell Maintenance

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Drosophila small ovary gene is required for transposon silencing and heterochromatin organization, and ensures germline stem cell maintenance and differentiation

Development ◽

10.1242/dev.170639 ◽

2018 ◽

Vol 145 (23) ◽

pp. dev170639 ◽

Cited By ~ 8

Author(s):

Ferenc Jankovics ◽

Melinda Bence ◽

Rita Sinka ◽

Anikó Faragó ◽

László Bodai ◽

...

Keyword(s):

Stem Cell ◽

Germline Stem Cell ◽

Stem Cell Maintenance ◽

Transposon Silencing ◽

Small Ovary ◽

Cell Maintenance

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Maintenance of high levels of pluripotent hematopoietic stem cells in vitro: effect of stromal cells and c-kit

Blood ◽

10.1182/blood.v81.2.365.bloodjournal812365 ◽

1993 ◽

Vol 81 (2) ◽

pp. 365-372 ◽

Cited By ~ 63

Author(s):

JP Wineman ◽

S Nishikawa ◽

CE Muller-Sieburg

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Line ◽

Stromal Cells ◽

Stromal Cell ◽

Hematopoietic Stem ◽

Stem Cell Maintenance ◽

Stromal Cell Line ◽

Cell Maintenance

We show here that mouse pluripotent hematopoietic stem cells can be maintained in vitro on stroma for at least 3 weeks at levels close to those found in bone marrow. The extent of stem cell maintenance is affected by the nature of the stromal cells. The stromal cell line S17 supported stem cells significantly better than heterogeneous, primary stromal layers or the stromal cell line Strofl-1. Stem cells cultured on S17 repopulated all hematopoietic lineages in marrow-ablated hosts for at least 10 months, indicating that this culture system maintained primitive stem cells with extensive proliferative capacity. Furthermore, we demonstrate that, while pluripotent stem cells express c-kit, this receptor appears to play only a minor role in stem cell maintenance in vitro. The addition of an antibody that blocks the interaction of c-kit with its ligand essentially abrogated myelopoiesis in cultures. However, the level of stem cells in antibody-treated cultures was similar to that found in untreated cultures. Thus, it seems likely that the maintenance of primitive stem cells in vitro depends on yet unidentified stromal cell-derived factor(s).

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me31B regulates stem cell homeostasis by preventing excess dedifferentiation in the Drosophila male germline

Journal of Cell Science ◽

10.1242/jcs.258757 ◽

2021 ◽

Author(s):

Lindy Jensen ◽

Zsolt G. Venkei ◽

George J. Watase ◽

Bitarka Bisai ◽

Scott Pletcher ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Critical Role ◽

Stem Cell Population ◽

Germline Stem Cells ◽

Cell Identity ◽

Stem Cell Maintenance ◽

Differentiated Cells ◽

Male Germline ◽

Elevated Frequency

Tissue-specific stem cells maintain tissue homeostasis by providing a continuous supply of differentiated cells throughout the life of organisms. Differentiated/differentiating cells can revert back to a stem cell identity via dedifferentiation to help maintain the stem cell pool beyond the lifetime of individual stem cells. Although dedifferentiation is important to maintain the stem cell population, it is speculated to underlie tumorigenesis. Therefore, this process must be tightly controlled. Here we show that a translational regulator me31B plays a critical role in preventing excess dedifferentiation in the Drosophila male germline: in the absence of me31B, spermatogonia (SGs) dedifferentiate into germline stem cells (GSCs) at a dramatically elevated frequency. Our results show that the excess dedifferentiation is likely due to misregulation of nos, a key regulator of germ cell identity and GSC maintenance. Taken together, our data reveal negative regulation of dedifferentiation to balance stem cell maintenance with differentiation.

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RNAi-based screens uncover a potential new role for the orphan neuropeptide receptor Moody in Drosophila female germline stem cell maintenance

PLoS ONE ◽

10.1371/journal.pone.0243756 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0243756

Author(s):

Tianlu Ma ◽

Shinya Matsuoka ◽

Daniela Drummond-Barbosa

Keyword(s):

Stem Cell ◽

Egg Production ◽

Large Scale ◽

Signal To Noise Ratio ◽

Egg Laying ◽

Melatonin Receptors ◽

Germline Stem Cell ◽

Stem Cell Maintenance ◽

Female Germline ◽

Cell Maintenance

Reproduction is highly sensitive to changes in physiology and the external environment. Neuropeptides are evolutionarily conserved signaling molecules that regulate multiple physiological processes. However, the potential reproductive roles of many neuropeptide signaling pathways remain underexplored. Here, we describe the results of RNAi-based screens in Drosophila melanogaster to identify neuropeptides/neuropeptide receptors with potential roles in oogenesis. The screen read-outs were either the number of eggs laid per female per day over time or fluorescence microscopy analysis of dissected ovaries. We found that the orphan neuropeptide receptor encoded by moody (homologous to mammalian melatonin receptors) is likely required in somatic cells for normal egg production and proper germline stem cell maintenance. However, the egg laying screens had low signal-to-noise ratio and did not lead to the identification of additional candidates. Thus, although egg count assays might be useful for large-scale screens to identify oogenesis regulators that result in dramatic changes in oogenesis, more labor-intensive microscopy-based screen are better applicable for identifying new physiological regulators of oogenesis with more subtle phenotypes.

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