scholarly journals RNA degradation sculpts the maternal transcriptome during Drosophila oogenesis

2020 ◽  
Author(s):  
Patrick Blatt ◽  
Siu Wah Wong-Deyrup ◽  
Alicia McCarthy ◽  
Shane Breznak ◽  
Matthew D. Hurton ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Rna Degradation ◽  
Germline Stem Cells ◽  
Drosophila Oogenesis ◽  
Maternal Rna ◽  
Early Stages ◽  
Decay Factor

AbstractIn sexually reproducing animals, the oocyte contributes a large supply of RNAs that are essential to launch development upon fertilization. The mechanisms that regulate the composition of the maternal RNA contribution during oogenesis are unclear. Here, we show that a subset of RNAs expressed during the early stages of oogenesis is subjected to regulated degradation during oocyte specification. Failure to remove these RNAs results in oocyte dysfunction and death. We identify the RNA-degrading Super Killer complex and No-Go Decay factor Pelota as key regulators of oogenesis via targeted clearance of RNAs expressed in germline stem cells. These regulators target RNAs enriched for cytidine sequences bound by the protein Half pint. Thus, RNA degradation helps orchestrate a germ cell-to-maternal transition by sculpting the maternal RNA contribution to the zygote.

scholarly journals Early Drosophila Oogenesis: A Tale of Centriolar Asymmetry

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1997
Author(s):  
Maria Giovanna Riparbelli ◽  
Veronica Persico ◽  
Giuliano Callaini
Keyword(s):  
Stem Cells ◽  
Dna Replication ◽  
Germ Cell ◽  
Developmental Stages ◽  
Germline Stem Cells ◽  
Drosophila Oogenesis ◽  
Early Stages ◽  
Duplication Events ◽  
Morphological Processes ◽  
Oocyte Selection

Among the morphological processes that characterize the early stages of Drosophila oogenesis, the dynamic of the centrioles deserves particular attention. We re-examined the architecture and the distribution of the centrioles within the germarium and early stages of the vitellarium. We found that most of the germ cell centrioles diverge from the canonical model and display notable variations in size. Moreover, duplication events were frequently observed within the germarium in the absence of DNA replication. Finally, we report the presence of an unusually long centriole that is first detected in the cystoblast and is always associated with the developing oocyte. This centriole is directly inherited after the asymmetric division of the germline stem cells and persists during the process of oocyte selection, thus already representing a marker for oocyte identification at the beginning of its formation and during the ensuing developmental stages.

scholarly journals The Controversy, Challenges, and Potential Benefits of Putative Female Germline Stem Cells Research in Mammals

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Zezheng Pan ◽  
Mengli Sun ◽  
Xia Liang ◽  
Jia Li ◽  
Fangyue Zhou ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Germ Cells ◽  
Mammalian Species ◽  
Research Progress ◽  
Germline Stem Cells ◽  
Conventional View ◽  
Proliferation And Differentiation ◽  
Potential Benefits ◽  
Female Germline

The conventional view is that female mammals lose their ability to generate new germ cells after birth. However, in recent years, researchers have successfully isolated and cultured a type of germ cell from postnatal ovaries in a variety of mammalian species that have the abilities of self-proliferation and differentiation into oocytes, and this finding indicates that putative germline stem cells maybe exist in the postnatal mammalian ovaries. Herein, we review the research history and discovery of putative female germline stem cells, the concept that putative germline stem cells exist in the postnatal mammalian ovary, and the research progress, challenge, and application of putative germline stem cells in recent years.

A role for the Drosophila bag-of-marbles protein in the differentiation of cystoblasts from germline stem cells

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2937-2947 ◽  
Author(s):  
D. McKearin ◽  
B. Ohlstein
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Germ Cell ◽  
Germ Cells ◽  
Germline Stem Cell ◽  
Cytoplasmic Protein ◽  
Germline Stem Cells ◽  
Bag Of Marbles

Cell differentiation commonly dictates a change in the cell cycle of mitotic daughters. Previous investigations have suggested that the Drosophila bag of marbles (bam) gene is required for the differentiation of germline stem cell daughters (cystoblasts) from the mother stem cells, perhaps by altering the cell cycle. In this paper, we report the preparation of antibodies to the Bam protein and the use of those reagents to investigate how Bam is required for germ cell development. We find that Bam exists as both a fusome component and as cytoplasmic protein and that cytoplasmic and fusome Bam might have separable activities. We also show that bam mutant germ cells are blocked in differentiation and are trapped as mitotically active cells like stem cells. A model for how Bam might regulate cystocyte differentiation is presented.

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

Development ◽  
1999 ◽  
Vol 126 (9) ◽  
pp. 1833-1844 ◽  
Author(s):  
F.J. King ◽  
H. Lin
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Genomic Region ◽  
Germline Stem Cell ◽  
Germline Stem Cells ◽  
Drosophila Oogenesis ◽  
Stem Cell Maintenance ◽  
Terminal Filament ◽  
Potential Signal ◽  
Cell Maintenance

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.

scholarly journals Spatio-temporal requirements for transposable element piRNA-mediated silencing during Drosophila oogenesis

2013 ◽  
Vol 42 (4) ◽  
pp. 2512-2524 ◽  
Author(s):  
Jérémy Dufourt ◽  
Cynthia Dennis ◽  
Antoine Boivin ◽  
Nathalie Gueguen ◽  
Emmanuelle Théron ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transposable Element ◽  
P Element ◽  
Genome Integrity ◽  
Germline Stem Cells ◽  
Next Generation ◽  
Drosophila Oogenesis ◽  
Genome Dynamics ◽  
Spatio Temporal ◽  
Pirna Pathway

Abstract During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotransposon in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P-element-based transgenes is also strongly weakened in these cysts. This region, termed the ‘Piwiless pocket’ or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts.

scholarly journals Male germline stem cells in non-human primates

2017 ◽  
Vol 4 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Swati Sharma ◽  
Joana M. D. Portela ◽  
Daniel Langenstroth-Röwer ◽  
Joachim Wistuba ◽  
Nina Neuhaus ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Germ Cells ◽  
Developmental Stages ◽  
Expression Patterns ◽  
Regulatory Mechanisms ◽  
Primate Species ◽  
Germline Stem Cells ◽  
Germline Development ◽  
Human Primate

Abstract. Over the past few decades, several studies have attempted to decipher the biology of mammalian germline stem cells (GSCs). These studies provide evidence that regulatory mechanisms for germ cell specification and migration are evolutionarily conserved across species. The characteristics and functions of primate GSCs are highly distinct from rodent species; therefore the findings from rodent models cannot be extrapolated to primates. Due to limited availability of human embryonic and testicular samples for research purposes, two non-human primate models (marmoset and macaque monkeys) are extensively employed to understand human germline development and differentiation. This review provides a broader introduction to the in vivo and in vitro germline stem cell terminology from primordial to differentiating germ cells. Primordial germ cells (PGCs) are the most immature germ cells colonizing the gonad prior to sex differentiation into testes or ovaries. PGC specification and migratory patterns among different primate species are compared in the review. It also reports the distinctions and similarities in expression patterns of pluripotency markers (OCT4A, NANOG, SALL4 and LIN28) during embryonic developmental stages, among marmosets, macaques and humans. This review presents a comparative summary with immunohistochemical and molecular evidence of germ cell marker expression patterns during postnatal developmental stages, among humans and non-human primates. Furthermore, it reports findings from the recent literature investigating the plasticity behavior of germ cells and stem cells in other organs of humans and monkeys. The use of non-human primate models would enable bridging the knowledge gap in primate GSC research and understanding the mechanisms involved in germline development. Reported similarities in regulatory mechanisms and germ cell expression profile in primates demonstrate the preclinical significance of monkey models for development of human fertility preservation strategies.

scholarly journals Krüppel-like factor 4 is required for development and regeneration of germline and yolk cells from somatic stem cells in planarians

2021 ◽  
Author(s):  
Melanie Issigonis ◽  
Akshada Redkar ◽  
Tania Rozario ◽  
Umair Khan ◽  
Rosa Mejia-Sanchez ◽  
...  
Keyword(s):  
Stem Cells ◽  
Germ Cell ◽  
Germ Cells ◽  
System Development ◽  
Primordial Germ Cells ◽  
Reproductive Organs ◽  
Germline Stem Cells ◽  
Yolk Cell ◽  
Evolutionary Innovation ◽  
Parasitic Flatworm

Sexually reproducing animals segregate their germline from their soma. In addition to gamete-producing gonads, planarian and parasitic flatworm reproduction relies on yolk-cell-generating accessory reproductive organs (vitellaria) supporting development of yolkless oocytes. Despite the importance of vitellaria for flatworm reproduction (and parasite transmission), little is known about this unique evolutionary innovation. Here we examine reproductive system development in the planarian Schmidtea mediterranea, in which pluripotent stem cells generate both somatic and germ cell lineages. We show that a homolog of the pluripotency factor Klf4 is expressed in primordial germ cells, presumptive germline stem cells, and yolk-cell progenitors. klf4 knockdown animals fail to specify or maintain germ cells; surprisingly, they also fail to maintain yolk cells. We find that yolk cells display germ-cell-like attributes and that vitellaria are structurally analogous to gonads. In addition to identifying a new proliferative cell population in planarians (yolk cell progenitors) and defining its niche, our work provides evidence supporting the hypothesis that flatworm germ cells and yolk cells share a common evolutionary origin.

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