scholarly journals DIV-1/PolA2 Promotes GLP-1/Notch-Mediated Cellular Events in Caenorhabditis elegans

2016 ◽  
Author(s):  
Dong Suk Yoon ◽  
Dong Seok Cha ◽  
Myon-Hee Lee
Keyword(s):  
Stem Cell ◽  
Notch Signaling ◽  
Cell Fate ◽  
Critical Role ◽  
Germline Stem Cell ◽  
Notch Activity ◽  
C Elegans ◽  
Cellular Events ◽  
Somatic Tissues ◽  
Germline Proliferation

ABSTRACTNotch signaling is a highly conserved cell signaling system in most multicellular organisms and plays a critical role in animal development. In various tumor cells, Notch signaling is elevated and has been considered as an important target in cancer treatments. In C. elegans, GLP-1 (one of two C. elegans Notch receptors) activity is required for cell fate specification in germline and somatic tissues. In this study, we have identified div-1 gene as a positive regulator for GLP-1/Notch-mediated cellular events. C. elegans div-1 encodes the B subunit of the DNA polymerase alpha-primase complex and is highly expressed in proliferative germ cells. Functional analyses demonstrated that i) DIV-1 is required for the robust proliferation typical of the germline, ii) loss of DIV-1 enhances and suppresses specific phenotypes that are associated with reduced and elevated GLP-1/Notch activity in germline and somatic tissues, and iii) DIV-1 works together with FBF/PUF proteins, downstream regulators of GLP-1/Notch signaling, to promote germline stem cell (GSC) maintenance and germline proliferation. To maintain GSCs and proliferative cell fate, GLP-1/Notch activity must remain above a threshold for proliferation/differentiation decision. Our results propose that DIV-1 may control the level of threshold for GLP-1/Notch-mediated germline proliferation. PolA2, a mammalian homolog of the C. elegans DIV-1, has been emerged as a therapeutic target for non-small cell lung cancer (NSCLC). Notably, Notch signaling is altered in approximately one third of NSCLCs. Therefore, the discovery of the DIV-1 effect on GLP-1/Notch-mediated cellular events has implications for our understanding of vertebrate PolA2 protein and its influence on stem cell maintenance and tumorigenesis.

scholarly journals Biology of the Caenorhabditis elegans Germline Stem Cell System

Genetics ◽  
2019 ◽  
Vol 213 (4) ◽  
pp. 1145-1188 ◽  
Author(s):  
E. Jane Albert Hubbard ◽  
Tim Schedl
Keyword(s):  
Stem Cell ◽  
Caenorhabditis Elegans ◽  
Cell Fate ◽  
Control Cell ◽  
Cell System ◽  
Germline Stem Cell ◽  
Cell Systems ◽  
Stem Cell Fate ◽  
C Elegans ◽  
Stem Cell System

Stem cell systems regulate tissue development and maintenance. The germline stem cell system is essential for animal reproduction, controlling both the timing and number of progeny through its influence on gamete production. In this review, we first draw general comparisons to stem cell systems in other organisms, and then present our current understanding of the germline stem cell system in Caenorhabditis elegans. In contrast to stereotypic somatic development and cell number stasis of adult somatic cells in C. elegans, the germline stem cell system has a variable division pattern, and the system differs between larval development, early adult peak reproduction and age-related decline. We discuss the cell and developmental biology of the stem cell system and the Notch regulated genetic network that controls the key decision between the stem cell fate and meiotic development, as it occurs under optimal laboratory conditions in adult and larval stages. We then discuss alterations of the stem cell system in response to environmental perturbations and aging. A recurring distinction is between processes that control stem cell fate and those that control cell cycle regulation. C. elegans is a powerful model for understanding germline stem cells and stem cell biology.

scholarly journals The exocyst complex regulates C. elegans germline stem cell proliferation by controlling membrane Notch levels

Development ◽  
2021 ◽  
Vol 148 (15) ◽  
Author(s):  
Kumari Pushpa ◽  
Sunayana Dagar ◽  
Harsh Kumar ◽  
Diksha Pathak ◽  
Sivaram V. S. Mylavarapu
Keyword(s):  
Cell Proliferation ◽  
Stem Cell ◽  
Plasma Membrane ◽  
Notch Signaling ◽  
Mammalian Cells ◽  
Germline Stem Cell ◽  
Stem Cell Proliferation ◽  
C Elegans ◽  
Exocyst Complex ◽  
Membrane Density

ABSTRACT The conserved exocyst complex regulates plasma membrane-directed vesicle fusion in eukaryotes. However, its role in stem cell proliferation has not been reported. Germline stem cell (GSC) proliferation in the nematode Caenorhabditis elegans is regulated by conserved Notch signaling. Here, we reveal that the exocyst complex regulates C. elegans GSC proliferation by modulating Notch signaling cell autonomously. Notch membrane density is asymmetrically maintained on GSCs. Knockdown of exocyst complex subunits or of the exocyst-interacting GTPases Rab5 and Rab11 leads to Notch redistribution from the GSC-niche interface to the cytoplasm, suggesting defects in plasma membrane Notch deposition. The anterior polarity (aPar) protein Par6 is required for GSC proliferation, and for maintaining niche-facing membrane levels of Notch and the exocyst complex. The exocyst complex biochemically interacts with the aPar regulator Par5 (14-3-3ζ) and Notch in C. elegans and human cells. Exocyst components are required for Notch plasma membrane localization and signaling in mammalian cells. Our study uncovers a possibly conserved requirement of the exocyst complex in regulating GSC proliferation and in maintaining optimal membrane Notch levels.

scholarly journals Distant activation of Notch signaling induces stem cell niche assembly

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009489
Author(s):  
Andriy S. Yatsenko ◽  
Halyna R. Shcherbata
Keyword(s):  
Stem Cell ◽  
Notch Signaling ◽  
Cell Fate ◽  
Stem Cell Niche ◽  
Germline Stem Cell ◽  
Cellular Interactions ◽  
Niche Assembly ◽  
Cell Niche ◽  
Germline Stem Cell Niche ◽  
Signaling Activation

Here we show that multiple modes of Notch signaling activation specify the complexity of spatial cellular interactions necessary for stem cell niche assembly. In particular, we studied the formation of the germline stem cell niche in Drosophila ovaries, which is a two-step process whereby terminal filaments are formed first. Then, terminal filaments signal to the adjacent cap cell precursors, resulting in Notch signaling activation, which is necessary for the lifelong acquisition of stem cell niche cell fate. The genetic data suggest that in order to initiate the process of stem cell niche assembly, Notch signaling is activated among non-equipotent cells via distant induction, where germline Delta is delivered to somatic cells located several diameters away via cellular projections generated by primordial germ cells. At the same time, to ensure the robustness of niche formation, terminal filament cell fate can also be induced by somatic Delta via cis- or trans-inhibition. This exemplifies a double security mechanism that guarantees that the germline stem cell niche is formed, since it is indispensable for the adjacent germline precursor cells to acquire and maintain stemness necessary for successful reproduction. These findings contribute to our understanding of the formation of stem cell niches in their natural environment, which is important for stem cell biology and regenerative medicine.

scholarly journals GLP-1 Notch - LAG-1 CSL control of the germline stem cell fate is mediated by transcriptional targets lst-1 and sygl-1

2019 ◽  
Author(s):  
Jian Chen ◽  
Ariz Mohammad ◽  
Nanette Pazdernik ◽  
Huiyan Huang ◽  
Beth Bowman ◽  
...  
Keyword(s):  
Stem Cell ◽  
Signaling Pathway ◽  
Cell Fate ◽  
Primary Response ◽  
Secondary Response ◽  
Germline Stem Cell ◽  
Cell Systems ◽  
Stem Cell Fate ◽  
Transcriptional Targets ◽  
C Elegans

AbstractStem cell systems are essential for the development and maintenance of polarized tissues. Intercellular signaling pathways control stem cell systems, where niche cells signal stem cells to maintain the stem cell fate/self renewal and inhibit differentiation. In the C. elegans germline, GLP-1 Notch signaling specifies the stem cell fate. We undertook a comprehensive genome-wide approach to identify transcriptional targets of GLP-1 signaling. We expected primary response target genes to be evident at the intersection of genes identified as directly bound by LAG-1, the C. elegans Notch pathway sequence-specific DNA binding protein, from ChIP-seq experiments, with genes identified as requiring GLP-1 signaling for RNA accumulation, from RNA-seq analysis. Furthermore, we performed a time-course transcriptomics analysis following auxin inducible degradation of LAG-1 to distinguish between genes whose RNA level was a primary or secondary response of GLP-1 signaling. Surprisingly, only lst-1 and sygl-1, the two known target genes of GLP-1 in the germline, fulfilled these criteria, indicating that these two genes are the primary response targets of GLP-1 Notch and may be the sole germline GLP-1 signaling protein-coding transcriptional targets for mediating the stem cell fate. In addition, three secondary response genes were identified based on their timing following loss of LAG-1, their lack of a LAG-1 ChIP-seq peak and that their glp-1 dependent mRNA accumulation could be explained by a requirement for lst-1 and sygl-1 activity. Moreover, our analysis also suggests that the function of the primary response genes lst-1 and sygl-1 can account for the glp-1 dependent peak protein accumulation of FBF-2, which promotes the stem cell fate and, in part, for the spatial restriction of elevated LAG-1 accumulation to the stem cell region.Author SummaryStem cell systems are central to tissue development, homeostasis and regeneration, where niche to stem cell signaling pathways promote the stem cell fate/self-renewal and inhibit differentiation. The evolutionarily conserved GLP-1 Notch signaling pathway in the C. elegans germline is an experimentally tractable system, allowing dissection of control of the stem cell fate and inhibition of meiotic development. However, as in many systems, the primary molecular targets of the signaling pathway in stem cells is incompletely known, as are secondary molecular targets, and this knowledge is essential for a deep understanding of stem cell systems. Here we focus on the identification of the primary transcriptional targets of the GLP-1 signaling pathway that promotes the stem cell fate, employing unbiased multilevel genomic approaches. We identify only lst-1 and sygl-1, two of a number of previously reported targets, as likely the sole primary mRNA transcriptional targets of GLP-1 signaling that promote the germline stem cell fate. We also identify secondary GLP-1 signaling RNA and protein targets, whose expression shows dependence on lst-1 and sygl-1, where the protein targets reinforce the importance of posttranscriptional regulation in control of the stem cell fate.

scholarly journals Non-autonomous regulation of germline stem cell proliferation by somatic MPK-1/MAPK activity in C. elegans

2020 ◽  
Author(s):  
Sarah Robinson-Thiewes ◽  
Benjamin Dufour ◽  
Pier-Olivier Martel ◽  
Xavier Lechasseur ◽  
Amani Ange Danielle Brou ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Stem Cell ◽  
Mitogen Activated Protein Kinase ◽  
Germline Stem Cell ◽  
Stem Cell Proliferation ◽  
C Elegans ◽  
Erk Mapk ◽  
Mapk Activity ◽  
Germline Differentiation ◽  
Germline Proliferation

AbstractExtracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) is a major positive regulator of cell proliferation that is often upregulated in cancer. Yet few studies have addressed ERK/MAPK regulation of proliferation within a complete organism. The C. elegans ERK/MAPK ortholog MPK-1 is best known for its control of somatic organogenesis and germline differentiation, but it also stimulates germline stem cell proliferation. Here we identify tissue-specific MPK-1 isoforms and characterize their distinct roles in germline function. The germline-specific MPK-1B isoform promotes germline differentiation, but has no apparent role in germline stem cell proliferation. By contrast, the soma-specific MPK-1A isoform promotes germline proliferation non-autonomously. Indeed, MPK-1A functions in the intestine or somatic gonad to promote germline proliferation, independently of its other known roles. We propose that a non-autonomous role of ERK/MAPK in stem cell proliferation may be conserved across species and other tissue types, with major clinical implications for cancer and other diseases.

scholarly journals Characterization of histone inheritance patterns in the Drosophila female germline

2020 ◽  
Author(s):  
Elizabeth W. Kahney ◽  
Lydia Sohn ◽  
Kayla Viets-Layng ◽  
Robert Johnston ◽  
Xin Chen
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Single Gene ◽  
Asymmetric Division ◽  
Germline Stem Cell ◽  
Inheritance Patterns ◽  
Daughter Cells ◽  
Dividing Cells ◽  
Female Germline

ABSTRACTStem cells have the unique ability to undergo asymmetric division which produces two daughter cells that are genetically identical, but commit to different cell fates. The loss of this balanced asymmetric outcome can lead to many diseases, including cancer and tissue dystrophy. Understanding this tightly regulated process is crucial in developing methods to treat these abnormalities. Here, we report that produced from a Drosophila female germline stem cell asymmetric division, the two daughter cells differentially inherit histones at key genes related to either maintaining the stem cell state or promoting differentiation, but not at constitutively active or silenced genes. We combined histone labeling with DNA Oligopaints to distinguish old versus new histone distribution and visualize their inheritance patterns at single-gene resolution in asymmetrically dividing cells in vivo. This strategy can be widely applied to other biological contexts involving cell fate establishment during development or tissue homeostasis in multicellular organisms.

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.

Sign in / Sign up

Export Citation Format

Share Document