scholarly journals Wolbachia control stem cell behavior and stimulate germline proliferation in filarial nematodes

2018 ◽  
Author(s):  
Foray Vincent ◽  
Pérez-Jiménez Mercedes M. ◽  
Fattouh Nour ◽  
Landmann Frédéric
Keyword(s):  
Stem Cell ◽  
Germline Stem Cell ◽  
Cell Behavior ◽  
Germline Stem Cells ◽  
Developmental Program ◽  
Symbiotic Interactions ◽  
Filarial Nematodes ◽  
A Cell ◽  
Germline Proliferation

SUMMARYAlthough symbiotic interactions are ubiquitous in the living world, examples of developmental symbioses are still scarce. We show here the crucial role of Wolbachia in the oogenesis of filarial nematodes, a class of parasites of biomedical and veterinary relevance. While the Wolbachia-depleted nematodes produce faulty embryos, we identified thanks to newly generated techniques the earliest requirements of Wolbachia in the germline. They stimulate its proliferation in a cell-autonomous manner, in parallel of the known key controllers, and not through nucleotide supplementation as previously hypothesized. We also found Wolbachia to maintain the quiescence of a pool of germline stem cells ensuring for many years a constant delivery of about 1400 eggs per day. The loss of quiescence upon Wolbachia depletion, as well as the disorganization of the distal germline suggest that Wolbachia are required to execute the proper germline stem cell developmental program in order to produce viable eggs and embryos.

scholarly journals Wolbachia Control Stem Cell Behavior and Stimulate Germline Proliferation in Filarial Nematodes

2018 ◽  
Vol 45 (2) ◽  
pp. 198-211.e3 ◽  
Author(s):  
Vincent Foray ◽  
Mercedes M. Pérez-Jiménez ◽  
Nour Fattouh ◽  
Frédéric Landmann
Keyword(s):  
Stem Cell ◽  
Cell Behavior ◽  
Filarial Nematodes ◽  
Germline Proliferation

scholarly journals Aubergine and piRNAs repress the proto-oncogene Cbl for germline stem cell self-renewal

2017 ◽  
Author(s):  
Patricia Rojas-Ríos ◽  
Aymeric Chartier ◽  
Martine Simonelig
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Mrna Translation ◽  
Translational Repression ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Cell Lineages

AbstractPIWI proteins have essential roles in germ cells and stem cell lineages. In Drosophila, Piwi is required in somatic niche cells and germline stem cells (GSCs) for GSC self-renewal and differentiation. Whether and how other PIWI proteins are involved in GSC biology remains unknown. Here, we show that Aubergine (Aub), another PIWI protein, is intrinsically required in GSCs for their self-renewal and differentiation. Aub loading with piRNAs is essential for these functions. The major role of Aub is in self-renewal and depends on mRNA regulation. We identify the Cbl proto-oncogene, a regulator of mammalian hematopoietic stem cells, as a novel GSC differentiation factor. Aub represses Cbl mRNA translation for GSC self-renewal, and does so through recruitment of the CCR4-NOT complex. This study reveals the role of piRNAs and PIWI proteins in translational repression for stem cell homeostasis and highlights piRNAs as major post-transcriptional regulators in key developmental decisions.

piwi encodes a nucleoplasmic factor whose activity modulates the number and division rate of germline stem cells

Development ◽  
2000 ◽  
Vol 127 (3) ◽  
pp. 503-514 ◽  
Author(s):  
D.N. Cox ◽  
A. Chao ◽  
H. Lin
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Division ◽  
Germline Stem Cell ◽  
Dual Function ◽  
Germline Stem Cells ◽  
Division Rate ◽  
Germline Expression ◽  
A Cell ◽  
Stem Cell Division

piwi represents the first class of genes known to be required for stem cell self-renewal in diverse organisms. In the Drosophila ovary, piwi is required in somatic signaling cells to maintain germline stem cells. Here we show that piwi encodes a novel nucleoplasmic protein present in both somatic and germline cells, with the highly conserved C-terminal region essential for its function. Removing PIWI protein from single germline stem cells significantly decreases the rate of their division. This suggests that PIWI has a second role as a cell-autonomous promoter of germline stem cell division. Consistent with its dual function, over-expression of piwi in somatic cells causes an increase both in the number of germline stem cells and the rate of their division. Thus, PIWI is a key regulator of stem cell division - its somatic expression modulates the number of germline stem cells and the rate of their division, while its germline expression also contributes to promoting stem cell division in a cell-autonomous manner.

scholarly journals Repression of differentiation genes by Hes transcription factors fuels neural tumour growth in Drosophila

2021 ◽  
Author(s):  
Chrysanthi Voutyraki ◽  
Alexandros Choromidis ◽  
Vasiliki Theodorou ◽  
Christina Efraimoglou ◽  
Gerasimos Anagnostopoulos ◽  
...  
Keyword(s):  
Stem Cell ◽  
Transcription Factors ◽  
Notch Signaling ◽  
Tumour Growth ◽  
Metabolic Reprogramming ◽  
Cell Physiology ◽  
Malignant Tumours ◽  
Rna Profiling ◽  
A Cell

Background: Neural stem cells (NSC) in divide asymmetrically to generate a cell that retains stem cell identity and another that is routed to differentiation. Prolonged mitotic activity of the NSCs gives rise to the plethora of neurons and glial cells that wire the brain and nerve cord. Genetic insults, such as excess of Notch signaling, perturb the normal NSC proliferation programs and trigger the formation of NSC hyperplasias, that can later progress to malignancies. Hes proteins are crucial mediators of Notch signaling and in the NSC context they act by repressing a cohort of early pro-differentiation transcription factors. Downregulation of these pro-differentiation factors makes NSC progeny cells susceptible to adopting an aberrant stem cell program. We have recently shown that Hes overexpression in Drosophila leads to NSC hyperplasias that progress to malignant tumours after allografting to adult hosts. Methods: We have combined genetic analysis, tissue allografting and transcriptomic approaches to address the role of Hes genes in NSC malignant transformation. Results: We show that the E(spl) genes are important mediators in the progression of Notch hyperplasias to malignancy, since allografts lacking the E(spl) genes grow much slower. We further present RNA profiling of Hes-induced tumours at two different stages after allografting. We find that the same cohort of differentiation-promoting transcription factors that are repressed in the primary hyperplasias continue to be downregulated after transplantation. This is accompanied by an upregulation of stress-response genes and metabolic reprogramming. Conclusions: The combination of dedifferentiation and cell physiology changes most likely drive tumour growth.

scholarly journals Klp10A, a stem cell centrosome-enriched kinesin, balances asymmetries in Drosophila male germline stem cell division

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Cuie Chen ◽  
Mayu Inaba ◽  
Zsolt G Venkei ◽  
Yukiko M Yamashita
Keyword(s):  
Stem Cell ◽  
Cell Division ◽  
Cell Fate ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
Male Germline ◽  
Mother And Daughter ◽  
Stem Cell Divisions ◽  
Stem Cell Division ◽  
Male Germline Stem Cells

Asymmetric stem cell division is often accompanied by stereotypical inheritance of the mother and daughter centrosomes. However, it remains unknown whether and how stem cell centrosomes are uniquely regulated and how this regulation may contribute to stem cell fate. Here we identify Klp10A, a microtubule-depolymerizing kinesin of the kinesin-13 family, as the first protein enriched in the stem cell centrosome in Drosophila male germline stem cells (GSCs). Depletion of klp10A results in abnormal elongation of the mother centrosomes in GSCs, suggesting the existence of a stem cell-specific centrosome regulation program. Concomitant with mother centrosome elongation, GSCs form asymmetric spindle, wherein the elongated mother centrosome organizes considerably larger half spindle than the other. This leads to asymmetric cell size, yielding a smaller differentiating daughter cell. We propose that klp10A functions to counteract undesirable asymmetries that may result as a by-product of achieving asymmetries essential for successful stem cell divisions.

Nanos and Pumilio have critical roles in the development and function of Drosophila germline stem cells

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 679-690 ◽  
Author(s):  
A. Forbes ◽  
R. Lehmann
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Germ Cells ◽  
Rna Binding ◽  
Drosophila Embryo ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
Embryonic Patterning ◽  
Germline Development ◽  
Egg Chambers

The zinc-finger protein Nanos and the RNA-binding protein Pumilio act together to repress the translation of maternal hunchback RNA in the posterior of the Drosophila embryo, thereby allowing abdomen formation. nanos RNA is localized to the posterior pole during oogenesis and the posteriorly synthesized Nanos protein is sequestered into the germ cells as they form in the embryo. This maternally provided Nanos protein is present in germ cells throughout embryogenesis. Here we show that maternally deposited Nanos protein is essential for germ cell migration. Lack of zygotic activity of nanos and pumilio has a dramatic effect on germline development of homozygous females. Given the coordinate function of nanos and pumilio in embryonic patterning, we analyzed the role of these genes in oogenesis. We find that both genes act in the germline. Although the nanos and pumilio ovarian phenotypes have similarities and both genes ultimately affect germline stem cell development, the focus of these phenotypes appears to be different. While pumilio mutant ovaries fail to maintain stem cells and all germline cells differentiate into egg chambers, the focus of nanos function seems to lie in the differentiation of the stem cell progeny, the cystoblast. Consistent with the model that nanos and pumilio have different phenotypic foci during oogenesis, we detect high levels of Pumilio protein in the germline stem cells and high levels of Nanos in the dividing cystoblasts. We therefore suggest that, in contrast to embryonic patterning, Nanos and Pumilio may interact with different partners in the germline.

Sign in / Sign up

Export Citation Format

Share Document