Faculty Opinions recommendation of Wnt signals and frizzled activity orient anterior-posterior axon outgrowth in C. elegans.

2006 ◽  
Author(s):  
Catherine Krull
Keyword(s):  
Axon Outgrowth ◽  
C Elegans ◽  
Anterior Posterior

scholarly journals Syndecan functions to regulate Wnt-dependent axon guidance in C. elegans

2016 ◽  
Author(s):  
Samantha N. Hartin ◽  
Meagan Kurland ◽  
Brian D. Ackley
Keyword(s):  
Axon Guidance ◽  
Specific Area ◽  
Axon Outgrowth ◽  
Surface Receptors ◽  
Over Expression ◽  
C Elegans ◽  
Continue Growth ◽  
Developmental Contexts ◽  
Termination Point ◽  
Anterior Posterior

AbstractCell adhesion molecules are key to axon guidance during development, for example specific cues can instruct axons to terminate in a specific area, or to continue growth. Syndecans are conserved cell-surface receptors that function in multiple developmental contexts. Caenorhabditis elegans with mutations in the single syndecan gene, sdn-1, exhibited errors in anterior-posterior guidance, with axons that stopped short of, or grew past their stereotypical termination point. Syndecan function was cell non-autonomous for GABAergic axon outgrowth during early development, but was likely cell autonomous to inhibit growth later in development. sdn-1 appeared to regulate the inhibitory activity of the egl-20/Wnt ligand. Removing egl-20 from sdn-1 mutants resulted in fewer animals with prematurely terminating axons. The proteoglycan modifying enzymes hse-5 and hst-2, but not hst-6, had similar effects, suggesting specific heparan sulfate modifications regulated EGL-20 axon-terminating activity. sdn-1 functioned with lin-17/Frizzled, bar-1/β-catenin and the egl-5 Hox-like transcription factor in EGL-20-depedent axon outgrowth. bar-1 was required for egl-5 expression in the most posterior GABAergic neurons. sdn-1 mutations did not eliminate egl-5 expression, but over-expression of egl-5 rescued sdn-1 phenotypes. Our results suggest syndecan is a component of Wnt-signaling events that are necessary for axons to recognize appropriate termination points.

scholarly journals Wnt Signals and Frizzled Activity Orient Anterior-Posterior Axon Outgrowth in C. elegans

2006 ◽  
Vol 10 (3) ◽  
pp. 379-390 ◽  
Author(s):  
Massimo A. Hilliard ◽  
Cornelia I. Bargmann
Keyword(s):  
Axon Outgrowth ◽  
C Elegans ◽  
Anterior Posterior

scholarly journals Interactions between the WEE-1.3 kinase and the PAM-1 aminopeptidase in oocyte maturation and the early C. elegans embryo

2021 ◽  
Author(s):  
Dorothy Benton ◽  
Eva C Jaeger ◽  
Arielle Kilner ◽  
Ashley Kimble ◽  
Josh Lowry ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Oocyte Maturation ◽  
Protective Role ◽  
C Elegans ◽  
Direct Target ◽  
The One ◽  
Actomyosin Cytoskeleton ◽  
Embryonic Viability ◽  
Anterior Posterior

Abstract Puromycin-sensitive aminopeptidases are found across phyla and are known to regulate the cell-cycle and play a protective role in neurodegenerative disease. PAM-1 is a puromycin-sensitive aminopeptidase important for meiotic exit and polarity establishment in the one-cell Caenorhabditis elegans embryo. Despite conservation of this aminopeptidase, little is known about its targets during development. In order to identify novel interactors, we conducted a suppressor screen and isolated four suppressing mutations in three genes that partially rescued the maternal-effect lethality of pam-1 mutants. Suppressed strains show improved embryonic viability and polarization of the anterior-posterior axis. We identified a missense mutation in wee-1.3 in one of these suppressed strains. WEE-1.3 is an inhibitory kinase that regulates maturation promoting factor. While the missense mutation suppressed polarity phenotypes in pam-1, it does so without restoring centrosome-cortical contact or altering the cortical actomyosin cytoskeleton. To see if PAM-1 and WEE-1.3 interact in other processes, we examined oocyte maturation. While depletion of wee-1.3 causes sterility due to precocious oocyte maturation, this effect was lessened in pam-1 worms, suggesting that PAM-1 and WEE-1.3 interact in this process. Levels of WEE-1.3 were comparable between wild-type and pam-1 strains, suggesting that WEE-1.3 is not a direct target of the aminopeptidase. Thus, we have established an interaction between PAM-1 and WEE-1.3 in multiple developmental processes and have identified suppressors that are likely to further our understanding of the role of puromycin-sensitive aminopeptidases during development.

scholarly journals pop-1/TCF, ref-2/ZIC and T-box factors regulate the development of anterior cells in the C. elegans embryo

2021 ◽  
Author(s):  
Jonathan D Rumley ◽  
Elicia A Preston ◽  
Dylan Cook ◽  
Felicia L Peng ◽  
Amanda L Zacharias ◽  
...  
Keyword(s):  
Wnt Pathway ◽  
Expression Patterns ◽  
Specific Expression ◽  
T Box ◽  
Animal Development ◽  
C Elegans ◽  
The Many ◽  
Necessary And Sufficient ◽  
Cell Division Timing ◽  
Anterior Posterior

Patterning of the anterior-posterior axis is fundamental to animal development. The Wnt pathway plays a major role in this process by activating the expression of posterior genes in animals from worms to humans. This observation raises the question of whether the Wnt pathway or other regulators control the expression of the many anterior-expressed genes. We found that the expression of five anterior-specific genes in Caenorhabditis elegans embryos depends on the Wnt pathway effectors pop-1/TCF and sys-1/β-catenin. We focused further on one of these anterior genes, ref-2/ZIC, a conserved transcription factor expressed in multiple anterior lineages. Live imaging of ref-2 mutant embryos identified defects in cell division timing and position in anterior lineages. Cis-regulatory dissection identified three ref-2 transcriptional enhancers, one of which is necessary and sufficient for anterior-specific expression. This enhancer is activated by the T-box transcription factors TBX-37 and TBX-38, and surprisingly, concatemerized TBX-37/38 binding sites are sufficient to drive anterior-biased expression alone, despite the broad expression of TBX-37 and TBX-38. Taken together, our results highlight the diverse mechanisms used to regulate anterior expression patterns in the embryo.

Specification of anterior-posterior differences within the AB lineage in the C. elegans embryo: a polarising induction

Development ◽  
1995 ◽  
Vol 121 (5) ◽  
pp. 1559-1568 ◽  
Author(s):  
H. Hutter ◽  
R. Schnabel
Keyword(s):  
Cell Fate ◽  
Tissue Type ◽  
Cell Stage ◽  
Anterior Portion ◽  
Developmental Potential ◽  
C Elegans ◽  
The Third ◽  
Inductive Signal ◽  
Anterior Posterior ◽  
Lineage Analysis

In a C. elegans embryo the third cleavages of descendants of the anterior blastomere AB of the 2-cell stage create pairs of blastomeres that develop differently. By laser ablation experiments we show that the fates of all the posterior daughters of this division depend on an induction occurring three cleavages before these blastomeres are born. The time of induction precludes a direct effect on cell fate. Alternatively, we suggest that the induction creates a heritable cell polarity which is propagated through several divisions. We suggest a model to demonstrate how a signal could be propagated through several rounds of cell division. An important implication of our observations is that this early induction acts to specify blastomere identity, not tissue type. A detailed lineage analysis revealed that altering the inductive signal alters complex lineage patterns as a whole. The induction described here, together with two inductions described previously can be used to illustrate how the anterior portion of the C. elegans embryo can be successively subdivided into blastomeres with unique developmental potential.

Mutant expression of male copulatory bursa surface markers in Caenorhabditis elegans

Development ◽  
1988 ◽  
Vol 103 (3) ◽  
pp. 485-495 ◽  
Author(s):  
C.D. Link ◽  
C.W. Ehrenfels ◽  
W.B. Wood
Keyword(s):  
Positional Information ◽  
Surface Expression ◽  
Surface Markers ◽  
Adult Males ◽  
Vulval Development ◽  
Altered Expression ◽  
C Elegans ◽  
Isolation And Characterization ◽  
Cuticle Development ◽  
Anterior Posterior

In a search for molecular markers of male tail morphogenesis in C. elegans, we have detected two surface markers that are specifically observed in the copulatory bursa of adult males and the vulva of adult hermaphrodites. These markers are defined by binding of a monoclonal antibody (Ab117) and the lectin wheat germ agglutinin (WGA) to live intact animals. Expression of these markers is dependent on sex, stage and anterior-posterior position in the animal. Four of ten mutants with specific defects in bursal development show altered expression of one or both markers. Because the WGA marker can be expressed in intersexual animals with very little bursal development, posterior surface expression of this marker can serve as an indication of subtle masculinization of hermaphrodites. The timing of expression of these markers is not affected by heterochronic mutations that cause larval animals to express adult cuticles or adult animals to express larval cuticles, indicating that marker expression can be uncoupled from general cuticle development. Mutant lin-22 males, which have an anterior-to-posterior transformation of cell fates in the lateral hypodermis, ectopically express both markers in a manner consistent with a ‘posteriorization’ of positional information in these animals. These markers should be useful for the isolation and characterization of mutants defective in bursal and vulval development, sex determination and expression of anterior-posterior positional information.

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