A splice acceptor mutation in C. elegans daf-19/Rfx disrupts functional specialization of male-specific ciliated neurons but does not affect ciliogenesis

Gene ◽  
2015 ◽  
Vol 559 (2) ◽  
pp. 196-202 ◽  
Author(s):  
Kristen L. Wells ◽  
Mazhgan Rowneki ◽  
Darrell J. Killian
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Douglas K. Reilly ◽  
Emily J. McGlame ◽  
Elke Vandewyer ◽  
Annalise N. Robidoux ◽  
Caroline S. Muirhead ◽  
...  

AbstractDioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.


Nematology ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 201-209 ◽  
Author(s):  
Eduardo Moreno ◽  
Ralf J. Sommer

Nematodes respond to a multitude of environmental cues. For example, the social behaviours clumping and bordering were described as a mechanism of hyperoxia avoidance in Caenorhabditis elegans and Pristionchus pacificus. A recent study in P. pacificus revealed a novel regulatory pathway that inhibits social behaviour in a response to an as yet unknown environmental cue. This environmental signal is recognised by ciliated neurons, as mutants defective in intraflagellar transport (IFT) proteins display social behaviours. The IFT machinery represents a large protein complex and many mutants in genes encoding IFT proteins are available in C. elegans. However, social phenotypes in C. elegans IFT mutants have never been reported. Here, we examined 15 previously isolated C. elegans IFT mutants and found that most of them showed strong social behaviour. These findings indicate conservation in the inhibitory mechanism of social behaviour between P. pacificus and C. elegans.


2017 ◽  
Author(s):  
Shu-Dan Yeh ◽  
Ayush Saxena ◽  
Timothy Crombie ◽  
Dorian Feistel ◽  
Lindsay M. Johnson ◽  
...  

AbstractAndrodioecious Caenorhabditis have a high frequency of self-compatible hermaphrodites and a low frequency of males. The effects of mutations on male fitness are of interest for two reasons. First, when males are rare, selection on male-specific mutations is less efficient than in hermaphrodites. Second, males may present a larger mutational target than hermaphrodites because of the different ways in which fitness accrues in the two sexes.We report the first estimates of male-specific mutational effects in an androdioecious organism. The rate of male-specific inviable or sterile mutations is ≤ 5 x 10−4/generation, below the rate at which males would be lost solely due to those kinds of mutations. The rate of mutational decay of male competitive fitness is ~0.17%/generation; that of hermaphrodite competitive fitness is ~0.11%/generation. The point estimate of ~1.5X faster rate of mutational decay of male fitness is nearly identical to the same ratio in Drosophila. Estimates of mutational variance (VM) for male mating success and competitive fitness are not significantly different from zero, whereas VM for hermaphrodite competitive fitness is similar to that of non-competitive fitness. The discrepancy between the two sexes is probably due to the greater inherent variability of mating relative to internal self-fertilization.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Zoë A Hilbert ◽  
Dennis H Kim

Animal behavior is directed by the integration of sensory information from internal states and the environment. Neuroendocrine regulation of diverse behaviors of Caenorhabditis elegans is under the control of the DAF-7/TGF-β ligand that is secreted from sensory neurons. Here, we show that C. elegans males exhibit an altered, male-specific expression pattern of daf-7 in the ASJ sensory neuron pair with the onset of reproductive maturity, which functions to promote male-specific mate-searching behavior. Molecular genetic analysis of the switch-like regulation of daf-7 expression in the ASJ neuron pair reveals a hierarchy of regulation among multiple inputs—sex, age, nutritional status, and microbial environment—which function in the modulation of behavior. Our results suggest that regulation of gene expression in sensory neurons can function in the integration of a wide array of sensory information and facilitate decision-making behaviors in C. elegans.


2021 ◽  
Author(s):  
Douglas K Reilly ◽  
Erich M Schwarz ◽  
Caroline S Muirhead ◽  
Annalise N Robidoux ◽  
Igor Antoscheckin ◽  
...  

The nematode Caenorhabditis elegans utilizes chemosensation to navigate an ever-changing environment for its survival. A class of secreted small-molecule pheromones, termed ascarosides, play an important role in olfactory perception by affecting a host of biological function ranging from development to behavior. The ascaroside ascr#8 mediates sex-specific behaviors, driving avoidance in hermaphrodites and attraction in males. Males sense ascr#8 via the ciliated male-specific cephalic sensory (CEM) neurons, which exhibit radial symmetry along dorsal-ventral and left-right axes. Calcium imaging studies suggest a complex neural coding mechanism that translates stochastic physiological responses in these neurons to reliable behavioral outputs. To test the hypothesis that the neurophysiological complexity arises from differential expression of genes within subsets of these neurons, we performed cell-specific transcriptomic profiling of these sensory neurons. Expression profiling revealed between 20 and 639 genes enriched at least two-fold per CEM neuron and identified multiple G protein coupled receptor (GPCR) candidates enriched in non-overlapping subsets of CEM neurons. GFP reporter analysis confirmed that RNA expression of two of the GPCR genes, srw-97 and dmsr-12, is enriched in specific subsets of the CEM neurons. Single CRISPR-Cas9 knockouts of either srw-97 or dmsr-12 resulted in partial defects, while a double knockout of both srw-97 and dmsr-12 completely abolished the attractive response to ascr#8, suggesting that each receptor acts in a non-redundant manner in discrete olfactory neurons. Together, our results suggest that the evolutionarily distinct GPCRs SRW-97 and DMSR-12 act to facilitate male-specific sensation of ascr#8 through discrete subsets of CEM neurons.


2021 ◽  
Author(s):  
Tessa Tekieli ◽  
Eviatar Yemini ◽  
Amin Nejatbakhsh ◽  
Erdem Varol ◽  
Robert W Fernandez ◽  
...  

Sex differences in the brain are prevalent throughout the animal kingdom and particularly well appreciated in the nematode C. elegans. While 294 neurons are shared between the two sexes, the nervous system of the male contains an additional 93 male-specific neurons, most of which have received very little attention so far. To make these neurons amenable for future study, we describe here how a multicolor, multipromoter reporter transgene, NeuroPAL, is capable of visualizing the distinct identities of all male specific neurons. We used this tool to visualize and characterize a number of features of the male-specific nervous system. We provide several proofs of concept for using NeuroPAL to identify the sites of expression of gfp-tagged reporter genes. We demonstrate the usage of NeuroPAL for cellular fate analysis by analyzing the effect of removal of developmental patterning genes, including a HOX cluster gene (egl-5), a miRNA (lin-4) and a proneural gene (lin-32/Ato), on neuronal identity acquisition within the male-specific nervous system. We use NeuroPAL and its intrinsic cohort of more than 40 distinct differentiation markers to show that, even though male-specific neurons are generated throughout all four larval stages, they execute their terminal differentiation program in a coordinated manner in the fourth larval stage that is concomitant with male tale retraction. This wave of differentiation couples neuronal maturation programs with the appearance of sexual organs. We call this wave 'just-in-time' differentiation by its analogy to the mechanism of 'just-in-time' transcription of metabolic pathway genes.


2020 ◽  
Author(s):  
Douglas K. Reilly ◽  
Emily J. McGlame ◽  
Elke Vandewyer ◽  
Annalise M. Robidoux ◽  
Haylea T. Northcott ◽  
...  

AbstractDioecious species are a hallmark of the animal kingdom, with opposing sexes responding differently to identical sensory cues. Here, we study the response of C. elegans’ to the small-molecule pheromone, ascr#8, which elicits opposing behavioral valences in each sex. We identify a novel neuropeptide-neuropeptide receptor (NP/NPR) module that is active in males, but not in hermaphrodites. Using a novel paradigm of neuropeptide rescue that we established, we leverage bacterial expression of individual peptides to rescue the sex-specific response to ascr#8. Concurrent biochemical studies confirmed individual FLP-3 peptides differentially activate two divergent receptors, NPR-10 and FRPR-16. Interestingly, the two of the peptides that rescued behavior in our feeding paradigm are related through a conserved threonine, suggesting that a specific NP/NPR combination sets a male state, driving the correct behavioral valence of the ascr#8 response. Receptor expression within pre-motor neurons reveals novel coordination of male-specific and core locomotory circuitries.


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