glp-1 can substitute for lin-12 in specifying cell fate decisions in Caenorhabditis elegans

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1019-1027 ◽  
Author(s):  
K. Fitzgerald ◽  
H.A. Wilkinson ◽  
I. Greenwald

Members of the lin-12/Notch gene family encode receptors for intercellular signals and are found throughout the animal kingdom. In many animals, the presence of at least two lin-12/Notch genes raises the issue of the significance of this duplication and divergence. In Caenorhabditis elegans, two lin-12/Notch genes, lin-12 and glp-1, encode proteins that are 50% identical, with different numbers of epidermal growth factor-like motifs in their extracellular domains. Many of the cell fate decisions mediated by lin-12 and glp-1 are distinct. Here, we express glp-1 protein under the control of lin-12 regulatory sequences in animals lacking endogenous lin-12 activity and find that glp-1 can substitute for lin-12 in mediating cell fate decisions. These results imply that the lin-12 and glp-1 proteins are biochemically interchangeable, sharing common ligand and effector proteins, and that the discrete lin-12 and glp-1 mutant phenotypes result from differential gene expression. In addition, these results suggest that the duplicate lin-12/Notch genes found in vertebrates may also be biochemically interchangeable.

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4275-4282 ◽  
Author(s):  
K. Fitzgerald ◽  
I. Greenwald

Ligands of the Delta/Serrate/lag-2 (DSL) family and their receptors, members of the lin-12/Notch family, mediate cell-cell interactions that specify cell fate in invertebrates and vertebrates. In C. elegans, two DSL genes, lag-2 and apx-1, influence different cell fate decisions during development. Here we show that APX-1 can fully substitute for LAG-2 when expressed under the control of lag-2 regulatory sequences. In addition, we demonstrate that truncated forms lacking the transmembrane and intracellular domains of both LAG-2 and APX-1 can also substitute for endogenous lag-2 activity. Moreover, we provide evidence that these truncated forms are secreted and able to activate LIN-12 and GLP-1 ectopically. Finally, we show that expression of a secreted DSL domain alone may enhance endogenous LAG-2 signalling. Our data suggest ways that activated forms of DSL ligands in other systems may be created.


Genetics ◽  
1991 ◽  
Vol 128 (2) ◽  
pp. 251-267 ◽  
Author(s):  
R V Aroian ◽  
P W Sternberg

Abstract The let-23 gene, which encodes a putative tyrosine kinase of the epidermal growth factor (EGF) receptor subfamily, has multiple functions during Caenorhabditis elegans development. We show that let-23 function is required for vulval precursor cells (VPCs) to respond to the signal that induces vulval differentiation: a complete loss of let-23 function results in no induction. However, some let-23 mutations that genetically reduce but do not eliminate let-23 function result in VPCs apparently hypersensitive to inductive signal: as many as five of six VPCs can adopt vulval fates, in contrast to the three that normally do. These results suggest that the let-23 receptor tyrosine kinase controls two opposing pathways, one that stimulates vulval differentiation and another that negatively regulates vulval differentiation. Furthermore, analysis of 16 new let-23 mutations indicates that the let-23 kinase functions in at least five tissues. Since various let-23 mutant phenotypes can be obtained independently, the let-23 gene is likely to have tissue-specific functions.


2014 ◽  
Vol 2 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Christense ME ◽  
Carolan BS

The Notch signaling pathway functions on cell fate decisions in a variety of different organizations in multicellular organisms, such as the hematopoietic system, nervous system, vascular system, skin and pancreas. In the majority of cases, Notch signaling blocks cell differentiation towards a primary process, and instead, direct them to a second differentiation. Altering the differentiation program or forcing it to remain in the undifferentiated state, there are several human diseases linked to defects in genes involved in Notch signaling, aberrant Notch signaling has been observed in a number of human cancers, suggesting a possible role of Notch signaling in tumor formation. Further, Recent study demonstrated an essential role for Notch1 in the corneal epithelial barrier recovery after wounding. We systematically searched the electronic PubMed database for research articles about Notch gene polymorphisms and diseases up to October 2013. Revman 5.0 software was adopted to conduct the meta-analysis. Crude odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated by either fixed-effects model or random-effects model. The present meta-analysis suggests that Notch gene polymorphisms are associated with the susceptibility of many diseases especially cancer.


2014 ◽  
Vol 2 (1) ◽  
pp. 1-4

The Notch signaling pathway functions on cell fate decisions in a variety of different organizations in multicellular organisms, such as the hematopoietic system, nervous system, vascular system, skin and pancreas. In the majority of cases, Notch signaling blocks cell differentiation towards a primary process, and instead, direct them to a second differentiation. Altering the differentiation program or forcing it to remain in the undifferentiated state, there are several human diseases linked to defects in genes involved in Notch signaling, aberrant Notch signaling has been observed in a number of human cancers, suggesting a possible role of Notch signaling in tumor formation. Further, Recent study demonstrated an essential role for Notch1 in the corneal epithelial barrier recovery after wounding. We systematically searched the electronic PubMed database for research articles about Notch gene polymorphisms and diseases up to October 2013. Revman 5.0 software was adopted to conduct the meta-analysis. Crude odds ratio (ORs) and 95% confidence intervals (95% CIs) were calculated by either fixed-effects model or random-effects model. The present meta-analysis suggests that Notch gene polymorphisms are associated with the susceptibility of many diseases especially cancer.


2016 ◽  
Vol 28 (11) ◽  
pp. 1663 ◽  
Author(s):  
D. Murta ◽  
M. Batista ◽  
A. Trindade ◽  
E. Silva ◽  
L. Mateus ◽  
...  

The oviduct and uterus undergo extensive cellular remodelling during the oestrous cycle, requiring finely tuned intercellular communication. Notch is an evolutionarily conserved cell signalling pathway implicated in cell fate decisions in several tissues. In the present study we evaluated the quantitative real-time polymerase chain reaction (real-time qPCR) and expression (immunohistochemistry) patterns of Notch components (Notch1–4, Delta-like 1 (Dll1), Delta-like 4 (Dll4), Jagged1–2) and effector (hairy/enhancer of split (Hes) 1–2, Hes5 and Notch-Regulated Ankyrin Repeat-Containing Protein (Nrarp)) genes in the mouse oviduct and uterus throughout the oestrous cycle. Notch genes are differentially transcribed and expressed in the mouse oviduct and uterus throughout the oestrous cycle. The correlated transcription levels of Notch components and effector genes, and the nuclear detection of Notch effector proteins, indicate that Notch signalling is active. The correlation between transcription levels of Notch genes and progesterone concentrations, and the association between expression of Notch proteins and progesterone receptor (PR) activation, indicate direct progesterone regulation of Notch signalling. The expression patterns of Notch proteins are spatially and temporally specific, resulting in unique expression combinations of Notch receptor, ligand and effector genes in the oviduct luminal epithelium, uterus luminal and glandular epithelia and uterine stroma throughout the oestrous cycle. Together, the results of the present study imply a regulatory role for Notch signalling in oviduct and uterine cellular remodelling occurring throughout the oestrous cycle.


2015 ◽  
Vol 5 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Yunting Chen ◽  
Iva Greenwald

Abstract Notch is a receptor that mediates cell–cell interactions that specify binary cell fate decisions in development and tissue homeostasis. Inappropriate Notch signaling is associated with cancer, and mutations in Notch pathway components have been associated with developmental diseases and syndromes. In Caenorhabditis elegans, suppressors of phenotypes associated with constitutively active LIN-12/Notch have identified many conserved core components and direct or indirect modulators. Here, we molecularly identify sel(ar584), originally isolated as a suppressor of a constitutively active allele of lin-12. We show that sel(ar584) is an allele of hecd-1, the ortholog of human HECDT1, a ubiquitin ligase that has been implicated in several different mammalian developmental events. We studied interactions of hecd-1 with lin-12 in the somatic gonad and with the other C. elegans Notch gene, glp-1, in the germ line. We found that hecd-1 acts as a positive modulator of lin-12/Notch activity in a somatic gonad context—the original basis for its isolation—but acts autonomously as a negative modulator of glp-1/Notch activity in the germ line. As the yeast ortholog of HECD-1, Ufd4p, has been shown to function in quality control, and C. elegans  HECD-1 has been shown to affect mitochondrial maintenance, we propose that the different genetic interactions between hecd-1 and Notch genes we observed in different cell contexts may reflect differences in quality control regulatory mechanisms or in cellular metabolism.


Development ◽  
2020 ◽  
Vol 147 (11) ◽  
pp. dev175760
Author(s):  
Louisa Mereu ◽  
Matthias K. Morf ◽  
Silvan Spiri ◽  
Peter Gutierrez ◽  
Juan M. Escobar-Restrepo ◽  
...  

2018 ◽  
Author(s):  
Jason R. Kroll ◽  
Jasonas Tsiaxiras ◽  
Jeroen S. van Zon

AbstractDuring development, cell fate decisions are often highly stochastic, but with the frequency of the different possible fates tightly controlled. To understand how signaling networks control the cell fate frequency of such random decisions, we studied the stochastic decision of the Caenorhabditis elegans P3.p cell to either fuse to the hypodermis or assume vulva precursor cell fate. Using time-lapse microscopy to measure the single-cell dynamics of two key inhibitors of cell fusion, the Hox gene LIN-39 and Wnt signaling through the β-catenin BAR-1, we uncovered significant variability in the dynamics of LIN-39 and BAR-1 levels. Most strikingly, we observed that BAR-1 accumulated in a single, 1-4 hour pulse at the time of the P3.p cell fate decision, with strong variability both in pulse slope and time of pulse onset. We found that the time of BAR-1 pulse onset was delayed relative to the time of cell fusion in mutants with low cell fusion frequency, linking BAR-1 pulse timing to cell fate outcome. Overall, a model emerged where animal-to-animal variability in LIN-39 levels and BAR-1 pulse dynamics biases cell fate by modulating their absolute level at the time cell fusion is induced. Our results highlight that timing of cell signaling dynamics, rather than its average level or amplitude, could play an instructive role in determining cell fate.Article summaryWe studied the stochastic decision of the Caenorhabditis elegans P3.p cell to either fuse to the hypodermis or assume vulva precursor cell fate. We uncovered significant variability in the dynamics of LIN-39/Hox and BAR-1/β-catenin levels, two key inhibitors of cell fusion. Surprisingly, we observed that BAR-1 accumulated in a 1-4 hour pulse at the time of the P3.p cell fate decision, with variable pulse slope and time of pulse onset. Our work suggests a model where animal-to-animal variability in LIN-39 levels and BAR-1 pulse dynamics biases cell fate by modulating their absolute level at the time cell fusion is induced.


Development ◽  
1990 ◽  
Vol 109 (4) ◽  
pp. 875-885 ◽  
Author(s):  
P.E. Hoppe ◽  
R.J. Greenspan

The Notch locus of Drosophila plays an important role in cell fate decisions within the neurogenic ectoderm, a role thought to involve interactions at the cell surface. We have assayed the requirement for Notch gene expression in epidermal cells by two kinds of genetic mosaics. First, with gynandromorphs, we removed the wild-type gene long before the critical developmental events to produce large mutant clones. The genotype of cells in large clones was scored by means of an antibody to the Notch protein. Second, using mitotic recombination, we removed the gene at successively later times after completion of the mitotically active early cleavage stages, to produce small clones. These clones were detected by means of a linked mutation of cuticle pattern, armadillo. The results of both experiments demonstrate a requirement for Notch expression by epidermal cells, and thus argue against the model that the Notch product acts as a signal required only in the neuroblast to influence neighboring epidermal cells. The mitotic recombination experiment revealed that Notch product is required by epidermal cells subsequent to neuroblast delamination. This result implies that the Notch gene functions to maintain the determined state of epidermal cells, possibly by mediating cell surface interactions within the epidermis.


2018 ◽  
Vol 115 (17) ◽  
pp. E3996-E4005 ◽  
Author(s):  
Jan P. Gerlach ◽  
Ingrid Jordens ◽  
Daniele V. F. Tauriello ◽  
Ineke van ‘t Land-Kuper ◽  
Jeroen M. Bugter ◽  
...  

Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt–FZD assemblies via intramembrane interactions. Subsequently, these Wnt–FZD–TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions.


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