scholarly journals A Putative Cation Channel, NCA-1, and a Novel Protein, UNC-80, Transmit Neuronal Activity in C. elegans

PLoS Biology ◽  
2008 ◽  
Vol 6 (3) ◽  
pp. e55 ◽  
Author(s):  
Edward Yeh ◽  
Sharon Ng ◽  
Mi Zhang ◽  
Magali Bouhours ◽  
Ying Wang ◽  
...  
Author(s):  
David (Wen Xiao) Wei

The insulin/insulin growth factor-1 (IGF-1) signalling (IIS) pathway plays a key role in metabolism, growth and development. Though research has elucidated aspects of this pathway, it is not fully characterized or understood. A better understanding of the pathway will give insight into related diseases such as cancer. To discover novel proteins involved in the IIS pathway, the C. elegans worm was used due to the homology its insulin/IGF-1 receptor shares with that of humans.  To identify novel protein interactions with the insulin/IGF-1 receptor, we performed a yeast two-hybrid screen using a library of worm proteins. We found several separate interactions with the worm homolog of the HSP90 protein. To support the involvement of HSP90 in the IIS pathway, we studied the phenotypes of worm strains with a mutant form of HSP90. They showed a similar phenotype to those that have a mutant form of the insulin/IGF-1 receptor, inappropriately entering a developmental stage known as dauer. This strongly suggests the involvement of HSP90 in the IIS pathway. Based on previous research, we hypothesized the interaction between HSP90 and the insulin/IGF-1 receptor may allow it to bind other proteins. Thus, we performed a modified yeast two-hybrid screen to identify proteins which interact with the receptor in the presence of HSP90. The screen identified 15 interactions, many more than with the insulin/IGF-1 receptor alone, supporting this hypothesis. Overall, we provide evidence of a novel interaction with insulin/IGF-1 receptor, suggesting HSP90 may be a potential target for developing therapies for IIS pathway related diseases.


Development ◽  
2000 ◽  
Vol 127 (4) ◽  
pp. 821-830 ◽  
Author(s):  
J. Larrain ◽  
D. Bachiller ◽  
B. Lu ◽  
E. Agius ◽  
S. Piccolo ◽  
...  

A number of genetic and molecular studies have implicated Chordin in the regulation of dorsoventral patterning during gastrulation. Chordin, a BMP antagonist of 120 kDa, contains four small (about 70 amino acids each) cysteine-rich domains (CRs) of unknown function. In this study, we show that the Chordin CRs define a novel protein module for the binding and regulation of BMPs. The biological activity of Chordin resides in the CRs, especially in CR1 and CR3, which have dorsalizing activity in Xenopus embryo assays and bind BMP4 with dissociation constants in the nanomolar range. The activity of individual CRs, however, is 5- to 10-fold lower than that of full-length Chordin. These results shed light on the molecular mechanism by which Chordin/BMP complexes are regulated by the metalloprotease Xolloid, which cleaves in the vicinity of CR1 and CR3 and would release CR/BMP complexes with lower anti-BMP activity than intact Chordin. CR domains are found in other extracellular proteins such as procollagens. Full-length Xenopus procollagen IIA mRNA has dorsalizing activity in embryo microinjection assays and the CR domain is required for this activity. Similarly, a C. elegans cDNA containing five CR domains induces secondary axes in injected Xenopus embryos. These results suggest that CR modules may function in a number of extracellular proteins to regulate growth factor signalling.


Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3615-3626 ◽  
Author(s):  
K.L. Chow ◽  
D.H. Hall ◽  
S.W. Emmons

The gene mab-21, which encodes a novel protein of 386 amino acids, is required for the choice of alternate cell fates by several cells in the C. elegans male tail. Three cells descended from the ray 6 precursor cell adopt fates of anterior homologs, and a fourth, lineally unrelated hypodermal cell is transformed into a neuroblast. The affected cells lie together in the lateral tail epidermis, suggesting that mab-21 acts as part of a short-range pattern-formation mechanism. Each of the changes in cell fate brought about by mab-21 mutants can be interpreted as a posterior-to-anterior homeotic transformation. mab-21 mutant males and hermaphrodites have additional pleiotropic phenotypes affecting movement, body shape and fecundity, indicating that mab-21 has functions outside the tail region of males. We show that the three known alleles of mab-21 are hypomorphs of a new gene. Mosaic analysis revealed that mab-21 acts cell autonomously to specify the properties of the sensory ray, but non-autonomously in the hypodermal versus neuroblast cell fate choice. Presence of cell signalling in the choice of the neuroblast fate was confirmed by cell ablation experiments. Mutations in mab-21 were shown previously to be genetic modifiers of the effects of HOM-C/Hox gene mutations on ray identity specification. The results presented here support the conclusion that mab-21 acts as part of a mechanism required for correct cell fate choice, possibly involving the function of HOM-C/Hox genes in several body regions.


Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 391-404 ◽  
Author(s):  
H. Browning ◽  
S. Strome

The paternal-effect embryonic-lethal gene, spe-11, is required for normal development of early C. elegans embryos. Spe-11 embryos fail to complete meiosis, form a weak eggshell, fail to orient properly the first mitotic spindle, and fail to undergo cytokinesis. Here we report cloning and sequencing of the spe-11 gene, which encodes a novel protein. As predicted by the paternal-effect mutant phenotype, the gene is expressed during spermatogenesis but is not detectable in females undergoing oogenesis, and the protein is present in mature sperm. To investigate whether SPE-11's essential function is during spermatogenesis or whether sperm-delivered SPE-11 functions in the newly fertilized embryo, we engineered animals to supply SPE-11 to the embryo through the oocyte rather than through the sperm. We found that maternal expression is sufficient for embryonic viability. This result demonstrates that SPE-11 is not required during spermatogenesis, and suggests that SPE-11 is a sperm-supplied factor that participates directly in development of the early embryo. In contrast to the many known maternal factors required for embryogenesis, SPE-11 is the first paternally contributed factor to be genetically identified and molecularly characterized.


2015 ◽  
Vol 113 (4) ◽  
pp. 1041-1050 ◽  
Author(s):  
Jeffrey A. Zahratka ◽  
Paul D. E. Williams ◽  
Philip J. Summers ◽  
Richard W. Komuniecki ◽  
Bruce A. Bamber

Monoamines and neuropeptides modulate neuronal excitability and synaptic strengths, shaping circuit activity to optimize behavioral output. In C. elegans, a pair of bipolar polymodal nociceptors, the ASHs, sense 1-octanol to initiate escape responses. In the present study, 1-octanol stimulated large increases in ASH Ca2+, mediated by L-type voltage-gated Ca2+ channels (VGCCs) in the cell soma and L-plus P/Q-type VGCCs in the axon, which were further amplified by Ca2+ released from intracellular stores. Importantly, 1-octanol-dependent aversive responses were not inhibited by reducing ASH L-VGCC activity genetically or pharmacologically. Serotonin, an enhancer of 1-octanol avoidance, potentiated 1-octanol-dependent ASH depolarization measured electrophysiologically, but surprisingly, decreased the ASH somal Ca2+ transients. These results suggest that ASH somal Ca2+ transient amplitudes may not always be predictive of neuronal depolarization and synaptic output. Therefore, although increases in steady-state Ca2+ can reliably indicate when neurons become active, quantitative relationships between Ca2+ transient amplitudes and neuronal activity may not be as straightforward as previously anticipated.


Cell ◽  
1995 ◽  
Vol 83 (6) ◽  
pp. 903-913 ◽  
Author(s):  
Kerry Kornfeld ◽  
Dennis B. Hom ◽  
H.Robert Horvitz

2019 ◽  
Author(s):  
Jesse A Cohn ◽  
Elizabeth R Cebul ◽  
Giulio Valperga ◽  
Mario de Bono ◽  
Maxwell G Heiman ◽  
...  

ABSTRACTNeuronal activity often leads to alterations in gene expression and cellular architecture. The nematode Caenorhabditis elegans, owing to its compact translucent nervous system, is a powerful system in which to study conserved aspects of the development and plasticity of neuronal morphology. Here we focus on one sensory neuron in the worm, termed URX, which senses oxygen and signals tonically proportional to environmental oxygen. Previous studies have reported that URX has variable branched endings at its dendritic sensory tip. By controlling oxygen levels and analyzing mutants, we found that these branched endings grow over time as a consequence of neuronal activity. Furthermore, we observed that the branches contain microtubules, but do not appear to harbor the guanylyl cyclase GCY-35, a central component of the oxygen sensory transduction pathway. Interestingly, we found that although URX dendritic tips grow branches in response to long-term activity, the degree of branch elaboration does not correlate with oxygen sensitivity at the cellular or the behavioral level. Given the strengths of C. elegans as a model organism, URX may serve as a potent system for uncovering genes and mechanisms involved in activity-dependent morphological changes in neurons.


2018 ◽  
Author(s):  
Ricardo J. Cordeiro Rodrigues ◽  
António Miguel de Jesus Domingues ◽  
Svenja Hellmann ◽  
Sabrina Dietz ◽  
Bruno F. M. de Albuquerque ◽  
...  

AbstractPiwi proteins are important for germ cell development in almost all animals studied thus far. These proteins are guided to specific targets, such as transposable elements, by small guide RNAs, often referred to as piRNAs, or 21U RNAs in C. elegans. In this organism, even though genetic screens have uncovered a number of potential 21U RNA biogenesis factors, little is known about how these factors interact or what they do. Based on the previously identified 21U biogenesis factor PID-1, we here define a novel protein complex, PETISCO, that is required for 21U RNA biogenesis. PETISCO contains both potential 5’-cap and 5’-phosphate RNA binding domains, suggesting involvement in 5’ end processing. We define the interaction architecture of PETISCO and reveal a second function for PETISCO in embryonic development. This essential function of PETISCO is not mediated by PID-1, but by TOST-1. Vice versa, TOST-1 is not involved in 21U RNA biogenesis. Both PID-1 and TOST-1 are small, intrinsically disordered proteins that interact directly with the PETISCO protein ERH-2 (enhancer of rudimentary homolog 2) using a conserved sequence motif. Finally, our data suggest an important role for TOST-1:PETISCO in SL1 homeostasis in the early embryo. Our work describes the first molecular platform for 21U RNA production in C. elegans, and strengthens the view that 21U RNA biogenesis is built upon a much more widely used, snRNA-related pathway.


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