scholarly journals The Immunoglobulin Superfamily Members syg-2 and syg-1 Regulate Neurite Development in C. elegans

2022 ◽  
Vol 10 (1) ◽  
pp. 3
Author(s):  
Dana K. Tucker ◽  
Chloe S. Adams ◽  
Gauri Prasad ◽  
Brian D. Ackley
Keyword(s):  
Axon Guidance ◽  
Immunoglobulin Superfamily ◽  
Genetic Pathway ◽  
C Elegans ◽  
Multiple Processes ◽  
Ig Superfamily ◽  
Essential Function ◽  
Neurite Development ◽  
To Receive ◽  
Anterior Posterior

Neurons form elaborate networks by guiding axons and dendrites to appropriate destinations. Neurites require information about the relative body axes during the initial projection from the cell body, and failure to receive or interpret those cues correctly can result in outgrowth errors. We identified a mutation in the Ig superfamily member syg-2 in a screen for animals with anterior/posterior (A/P) axon guidance defects. We found that syg-2 and its cognate Ig family member syg-1 appear to function in a linear genetic pathway to control the outgrowth of GABAergic axons. We determined that this pathway works in parallel to Wnt signaling. Specifically, mutations in syg-2 or syg-1 selectively affected the embryonically derived Dorsal D-type (DD) GABAergic neurons. We found no evidence that these mutations affected the Ventral D-type neurons (VD) that form later, during the first larval stage. In addition, mutations in syg-1 or syg-2 could result in the DD neurons forming multiple processes, becoming bipolar, rather than the expected pseudounipolar morphology. Given SYG-2′s essential function in synaptogenesis of the hermaphrodite-specific neurons (HSNs), we also examined DD neuron synapses in syg-2 mutants. We found syg-2 mutants had a decreased number of synapses formed, but synaptic morphology was largely normal. These results provide further evidence that the GABAergic motorneurons use multiple guidance pathways during development.

Semaphorin 1a and semaphorin 1b are required for correct epidermal cell positioning and adhesion during morphogenesis in C. elegans

Development ◽  
2002 ◽  
Vol 129 (9) ◽  
pp. 2065-2078
Author(s):  
Val E. Ginzburg ◽  
Peter J. Roy ◽  
Joseph G. Culotti
Keyword(s):  
Axon Guidance ◽  
Transmembrane Proteins ◽  
Precursor Cell ◽  
Deletion Mutants ◽  
Normal Position ◽  
C Elegans ◽  
Seam Cell ◽  
Ray Cells ◽  
Cell Positioning ◽  
Anterior Posterior

The semaphorin family comprises secreted and transmembrane proteins involved in axon guidance and cell migration. We have isolated and characterized deletion mutants of C. elegans semaphorin 1a (Ce-sema-1a or smp-1) and semaphorin 1b (Ce-sema-1b or smp-2) genes. Both mutants exhibit defects in epidermal functions. For example, the R1.a-derived ray precursor cells frequently fail to change anterior/posterior positions completely relative to their sister tail lateral epidermal precursor cell R1.p, causing ray 1 to be formed anterior to its normal position next to ray 2. The ray cells, which normally separate from the lateral tail seam cell (SET) at the end of L4 stage, remains connected to the SET cell even in adult mutant males. The ray 1 defects are partially penetrant in each single Ce-sema-1 mutant at 20°C, but are greatly enhanced in Ce-sema-1 double mutants, suggesting that Ce-Sema-1a and Ce-Sema-1b function in parallel to regulate ray 1 position. Both mutants also have defects in other aspects of epidermal functions, including head and tail epidermal morphogenesis and touch cell axon migration, whereas, smp-1 mutants alone have defects in defecation and brood size. A feature of smp-1 mutants that is shared with mutants of mab-20 (which encodes Sema-2a) is the abnormal perdurance of contacts between epidermal cells.

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 The Conserved Immunoglobulin Superfamily Member SAX-3/Robo Directs Multiple Aspects of Axon Guidance in C. elegans

Cell ◽  
1998 ◽  
Vol 92 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Jennifer A Zallen ◽  
B.Alexander Yi ◽  
Cornelia I Bargmann
Keyword(s):  
Axon Guidance ◽  
Immunoglobulin Superfamily ◽  
C Elegans

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.

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