scholarly journals Neuronal regulated Ire1-dependent mRNA decay controls germline differentiation in C. elegans

2020 ◽  
Author(s):  
Mor Levi-Ferber ◽  
Rewayd Shalash ◽  
Adrien Le-Thomas ◽  
Yehuda Salzberg ◽  
Maor Shurgi ◽  
...  
Keyword(s):  
Er Stress ◽  
Tumor Cells ◽  
Cell Fate ◽  
Germ Cells ◽  
Mrna Decay ◽  
Neuronal Circuit ◽  
C Elegans ◽  
Animal Physiology ◽  
Molecular Events ◽  
Germline Differentiation

Understanding the molecular events that regulate cell pluripotency versus acquisition of differentiated somatic cell fate is fundamentally important. Studies in C. elegans demonstrate that knockout of the germline-specific translation repressor gld-1, causes germ cells within tumorous gonads to form germline-derived teratoma. Previously we demonstrated that ER stress enhances this phenotype to suppress germline tumor progression (Levi-Ferber M, 2015). Here, we identify a neuronal circuit that non-autonomously suppresses germline differentiation, and show that it communicates with the gonad via the neurotransmitter serotonin to limit somatic differentiation of the tumorous germline. ER stress controls this circuit through regulated IRE-1-dependent mRNA decay of transcripts encoding the neuropeptide FLP-6. Depletion of FLP-6 disrupts the circuit's integrity and hence its ability to prevent somatic-fate acquisition by germline tumor cells. Our findings reveal mechanistically how ER stress enhances ectopic germline differentiation, and demonstrate that RIDD can affect animal physiology by controlling a specific neuronal circuit.

scholarly journals Neuronal regulated ire-1-dependent mRNA decay controls germline differentiation in Caenorhabditis elegans

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Mor Levi-Ferber ◽  
Rewayd Shalash ◽  
Adrien Le-Thomas ◽  
Yehuda Salzberg ◽  
Maor Shurgi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Caenorhabditis Elegans ◽  
Er Stress ◽  
Cell Fate ◽  
Germ Cells ◽  
Mrna Decay ◽  
Neuronal Circuit ◽  
Animal Physiology ◽  
Molecular Events ◽  
Germline Differentiation

Understanding the molecular events that regulate cell pluripotency versus acquisition of differentiated somatic cell fate is fundamentally important. Studies in Caenorhabditis elegans demonstrate that knockout of the germline-specific translation repressor gld-1 causes germ cells within tumorous gonads to form germline-derived teratoma. Previously we demonstrated that endoplasmic reticulum (ER) stress enhances this phenotype to suppress germline tumor progression(Levi-Ferber et al., 2015). Here, we identify a neuronal circuit that non-autonomously suppresses germline differentiation and show that it communicates with the gonad via the neurotransmitter serotonin to limit somatic differentiation of the tumorous germline. ER stress controls this circuit through regulated inositol requiring enzyme-1 (IRE-1)-dependent mRNA decay of transcripts encoding the neuropeptide FLP-6. Depletion of FLP-6 disrupts the circuit’s integrity and hence its ability to prevent somatic-fate acquisition by germline tumor cells. Our findings reveal mechanistically how ER stress enhances ectopic germline differentiation and demonstrate that regulated Ire1-dependent decay can affect animal physiology by controlling a specific neuronal circuit.

scholarly journals Genetic control of programmed cell death in the Caenorhabditis elegans hermaphrodite germline

Development ◽  
1999 ◽  
Vol 126 (5) ◽  
pp. 1011-1022 ◽  
Author(s):  
T.L. Gumienny ◽  
E. Lambie ◽  
E. Hartwieg ◽  
H.R. Horvitz ◽  
M.O. Hengartner
Keyword(s):  
Cell Death ◽  
Caenorhabditis Elegans ◽  
Germ Cell ◽  
Somatic Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Mapk Pathway ◽  
Apoptotic Cell ◽  
C Elegans ◽  
Pathway Activation

Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. Germ cell death requires ras/MAPK pathway activation and is used to maintain germline homeostasis. We suggest that apoptosis eliminates excess germ cells that acted as nurse cells to provide cytoplasmic components to maturing oocytes.

scholarly journals Transdifferentiation mediated tumor suppression by the endoplasmic reticulum stress sensor IRE-1 in C. elegans

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Mor Levi-Ferber ◽  
Hai Gian ◽  
Reut Dudkevich ◽  
Sivan Henis-Korenblit
Keyword(s):  
Tumor Cell ◽  
Er Stress ◽  
Tumor Progression ◽  
Tumor Cells ◽  
Tumor Therapy ◽  
Tumor Model ◽  
Apoptosis Resistance ◽  
Stress Sensor ◽  
C Elegans ◽  
Cell Transdifferentiation

Deciphering effective ways to suppress tumor progression and to overcome acquired apoptosis resistance of tumor cells are major challenges in the tumor therapy field. We propose a new concept by which tumor progression can be suppressed by manipulating tumor cell identity. In this study, we examined the effect of ER stress on apoptosis resistant tumorous cells in a Caenorhabditis elegans germline tumor model. We discovered that ER stress suppressed the progression of the lethal germline tumor by activating the ER stress sensor IRE-1. This suppression was associated with the induction of germ cell transdifferentiation into ectopic somatic cells. Strikingly, transdifferentiation of the tumorous germ cells restored their ability to execute apoptosis and enabled their subsequent removal from the gonad. Our results indicate that tumor cell transdifferentiation has the potential to combat cancer and overcome the escape of tumor cells from the cell death machinery.

scholarly journals A hydraulic instability drives the cell death decision in the nematode germline

2020 ◽  
Author(s):  
N. T. Chartier ◽  
A. Mukherjee ◽  
J. Pfanzelter ◽  
S. Fürthauer ◽  
B. T. Larson ◽  
...  
Keyword(s):  
Decision Making ◽  
Cell Death ◽  
Cell Fate ◽  
Germ Cells ◽  
Cell Fate Decision ◽  
Homogeneous Population ◽  
C Elegans ◽  
The Common ◽  
Fate Decision ◽  
Cell Volumes

AbstractOocytes are large and resourceful. During oogenesis some germ cells grow, typically at the expense of others that undergo apoptosis. How germ cells are selected to live or die out of a homogeneous population remains unclear. Here we show that this cell fate decision in C. elegans is mechanical and related to tissue hydraulics. Germ cells become inflated when the pressure inside them is lower than in the common cytoplasmic pool. This condition triggers a hydraulic instability which amplifies volume differences and causes some germ cells to grow and others to shrink. Shrinking germ cells are extruded and die, as we demonstrate by reducing germ cell volumes via thermoviscous pumping. Together, this reveals a robust mechanism of mechanochemical cell fate decision making in the germline.

TRA-1A regulates transcription of fog-3, which controls germ cell fate in C. elegans

Development ◽  
2000 ◽  
Vol 127 (14) ◽  
pp. 3119-3129 ◽  
Author(s):  
P. Chen ◽  
R.E. Ellis
Keyword(s):  
Transcriptional Regulation ◽  
Sexual Identity ◽  
Cell Fate ◽  
Zinc Finger ◽  
Germ Cells ◽  
Zinc Finger Protein ◽  
Rt Pcr ◽  
C Elegans ◽  
Finger Protein

In C. elegans, the zinc-finger protein TRA-1A is thought to be the final arbiter of somatic sexual identity. We show that fog-3, which is required for germ cells to become sperm rather than oocytes, is a target of TRA-1A. First, northern analyses and RT-PCR experiments indicate that expression of fog-3 is controlled by tra-1. Second, studies of double mutants show that this control could be direct. Third, the fog-3 promoter contains multiple sites that bind TRA-1A in gel shift assays, and mutations in these sites alter activity of fog-3 in vivo. These results establish fog-3 as one of the first known targets of transcriptional regulation by TRA-1A. Furthermore, they show that tra-1 controls a terminal regulator of sexual fate in germ cells, just as it is thought to do in the soma.

Transformation of the germ line into muscle in mes-1 mutant embryos of C. elegans

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 2961-2972 ◽  
Author(s):  
S. Strome ◽  
P. Martin ◽  
E. Schierenberg ◽  
J. Paulsen
Keyword(s):  
Cell Fate ◽  
Germ Cells ◽  
Germ Line ◽  
Primordial Germ Cells ◽  
Primordial Germ Cell ◽  
Wild Type ◽  
C Elegans ◽  
Stem Cell Divisions ◽  
Asymmetric Partitioning

Mutations in the maternal-effect sterile gene mes-1 cause the offspring of homozygous mutant mothers to develop into sterile adults. Lineage analysis revealed that mutant offspring are sterile because they fail to form primordial germ cells during embryogenesis. In wild-type embryos, the primordial germ cell P4 is generated via a series of four unequal stem-cell divisions of the zygote. mes-1 embryos display a premature and progressive loss of polarity in these divisions: P0 and P1 undergo apparently normal unequal divisions and cytoplasmic partitioning, but P2 (in some embryos) and P3 (in most embryos) display defects in cleavage asymmetry and fail to partition lineage-specific components to only one daughter cell. As an apparent consequence of these defects, P4 is transformed into a muscle precursor, like its somatic sister cell D, and generates up to 20 body muscle cells instead of germ cells. Our results show that the wild-type mes-1 gene participates in promoting unequal germ-line divisions and asymmetric partitioning events and thus the determination of cell fate in early C. elegans embryos.

scholarly journals The C. elegans SET-2 histone methyltransferase maintains germline fate by preventing progressive transcriptomic deregulation across generations

2019 ◽  
Author(s):  
Valérie J. Robert ◽  
Andrew K. Knutson ◽  
Andreas Rechtsteiner ◽  
Gaël Yvert ◽  
Susan Strome ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Cell Fate ◽  
Germ Cells ◽  
Expression Profiling ◽  
Histone H3 ◽  
Principal Component ◽  
Transcriptional Program ◽  
C Elegans ◽  
Chromatin Regulator ◽  
Germline Genes

AbstractChromatin factors contribute to germline maintenance by preserving a germline-appropriate transcriptional program. In the absence of the conserved histone H3 Lys4 (H3K4) methyltransferase SET-2, C. elegans germ cells progressively lose their identity over generations, leading to sterility. How this transgenerational loss of fertility results from the absence of SET-2 is unknown. Here we performed expression profiling across generations on germlines from mutant animals lacking SET-2 activity. We found that gene deregulation occurred in 2 steps: a priming step in early generations progressing to loss of fertility in later generations. By performing Within-Class Analysis (WCA), a derivative of Principal Component Analysis, we identified transcriptional signatures associated with SET-2 inactivation, both at the priming step and later on during loss of fertility. Further analysis showed that repression of germline genes, derepression of somatic programs, and X-chromosome desilencing through interference with PRC2-dependent repression, are priming events driving loss of germline identity in the absence of SET-2. Decreasing expression of identified priming genes, including the C/EBP homologue cebp-1 and TGF-β pathway components, was sufficient to delay the onset of sterility, suggesting that they individually contribute to the loss of germ cell fate. Altogether, our findings illustrate how the loss of a chromatin regulator at one generation can progressively deregulate multiple transcriptional and signaling programs, ultimately leading to loss of appropriate cell fate.

scholarly journals Conversion of Germ Cells to Somatic Cell Types in C. elegans

2020 ◽  
Vol 8 (4) ◽  
pp. 24 ◽  
Author(s):  
Nida ul Fatima ◽  
Baris Tursun
Keyword(s):  
Transcription Factor ◽  
Germ Cell ◽  
Somatic Cell ◽  
Cell Fate ◽  
Germ Cells ◽  
Molecular Mechanisms ◽  
Essential Property ◽  
C Elegans ◽  
Differentiated Cells ◽  
A Cell

The potential of a cell to produce all types of differentiated cells in an organism is termed totipotency. Totipotency is an essential property of germ cells, which constitute the germline and pass on the parental genetic material to the progeny. The potential of germ cells to give rise to a whole organism has been the subject of intense research for decades and remains important in order to better understand the molecular mechanisms underlying totipotency. A better understanding of the principles of totipotency in germ cells could also help to generate this potential in somatic cell lineages. Strategies such as transcription factor-mediated reprogramming of differentiated cells to stem cell-like states could benefit from this knowledge. Ensuring pluripotency or even totipotency of reprogrammed stem cells are critical improvements for future regenerative medicine applications. The C. elegans germline provides a unique possibility to study molecular mechanisms that maintain totipotency and the germ cell fate with its unique property of giving rise to meiotic cells Studies that focused on these aspects led to the identification of prominent chromatin-repressing factors such as the C. elegans members of the Polycomb Repressive Complex 2 (PRC2). In this review, we summarize different factors that were recently identified, which use molecular mechanisms such as control of protein translation or chromatin repression to ensure maintenance of totipotency and the germline fate. Additionally, we focus on recently identified factors involved in preventing transcription-factor-mediated conversion of germ cells to somatic lineages. These so-called reprogramming barriers have been shown in some instances to be conserved with regard to their function as a cell fate safeguarding factor in mammals. Overall, continued studies assessing the different aspects of molecular pathways involved in maintaining the germ cell fate in C. elegans may provide more insight into cell fate safeguarding mechanisms also in other species.

Specification of Germ Cell Fates by FOG-3 Has Been Conserved During Nematode Evolution

Genetics ◽  
2001 ◽  
Vol 158 (4) ◽  
pp. 1513-1525 ◽  
Author(s):  
Pei-Jiun Chen ◽  
Soochin Cho ◽  
Suk-Won Jin ◽  
Ronald E Ellis
Keyword(s):  
Cell Fate ◽  
Germ Cells ◽  
Mating Systems ◽  
Germ Line ◽  
Model Organism ◽  
Cell Fates ◽  
C Elegans ◽  
Rapid Changes ◽  
Self Fertilization ◽  
Sexual Traits

Abstract Rapid changes in sexual traits are ubiquitous in evolution. To analyze this phenomenon, we are studying species of the genus Caenorhabditis. These animals use one of two different mating systems—male/hermaphroditic, like the model organism Caenorhabditis elegans, or male/female, like C. remanei. Since hermaphrodites are essentially females that produce sperm for self-fertilization, elucidating the control of cell fate in the germ line in each species could provide the key to understanding how these mating systems evolved. In C. elegans, FOG-3 is required to specify that germ cells become sperm. Thus, we cloned its homologs from both C. remanei and C. briggsae. Each species produces a single homolog of FOG-3, and RNA-mediated interference indicates that FOG-3 functions in each species to specify that germ cells develop as sperm rather than as oocytes. What factors account for the different mating systems? Northern analyses and RT-PCR data reveal that the expression of fog-3 is always correlated with spermatogenesis. Since the promoters for all three fog-3 genes contain binding sites for the transcription factor TRA-1A and are capable of driving expression of fog-3 in C. elegans hermaphrodites, we propose that alterations in the upstream sex-determination pathway, perhaps acting through TRA-1A, allow spermatogenesis in C. elegans and C. briggsae XX larvae but not in C. remanei.

scholarly journals Induced Neurons From Germ Cells in Caenorhabditis elegans

2021 ◽  
Vol 15 ◽  
Author(s):  
Iris Marchal ◽  
Baris Tursun
Keyword(s):  
Caenorhabditis Elegans ◽  
Regenerative Medicine ◽  
Cell Fate ◽  
Germ Cells ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Therapeutic Approaches ◽  
C Elegans ◽  
Cell Fate Conversion ◽  
Induced Neurons

Cell fate conversion by the forced overexpression of transcription factors (TFs) is a process known as reprogramming. It leads to de-differentiation or trans-differentiation of mature cells, which could then be used for regenerative medicine applications to replenish patients suffering from, e.g., neurodegenerative diseases, with healthy neurons. However, TF-induced reprogramming is often restricted due to cell fate safeguarding mechanisms, which require a better understanding to increase reprogramming efficiency and achieve higher fidelity. The germline of the nematode Caenorhabditis elegans has been a powerful model to investigate the impediments of generating neurons from germ cells by reprogramming. A number of conserved factors have been identified that act as a barrier for TF-induced direct reprogramming of germ cells to neurons. In this review, we will first summarize our current knowledge regarding cell fate safeguarding mechanisms in the germline. Then, we will focus on the molecular mechanisms underlying neuronal induction from germ cells upon TF-mediated reprogramming. We will shortly discuss the specific characteristics that might make germ cells especially fit to change cellular fate and become neurons. For future perspectives, we will look at the potential of C. elegans research in advancing our knowledge of the mechanisms that regulate cellular identity, and what implications this has for therapeutic approaches such as regenerative medicine.

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