scholarly journals Identification of Nonviable Genes Affecting Touch Sensitivity in Caenorhabditis elegans Using Neuronally Enhanced Feeding RNA Interference

2015 ◽  
Vol 5 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Xiaoyin Chen ◽  
Margarete Diaz Cuadros ◽  
Martin Chalfie
Keyword(s):  
Rna Interference ◽  
Caenorhabditis Elegans ◽  
The Body ◽  
Genetic Screens ◽  
Tubulin Acetylation ◽  
Touch Receptor Neurons ◽  
Touch Sensitivity ◽  
Touch Response ◽  
Receptor Neurons ◽  
Neuronal Functions

Abstract Caenorhabditis elegans senses gentle touch along the body via six touch receptor neurons. Although genetic screens and microarray analyses have identified several genes needed for touch sensitivity, these methods miss pleiotropic genes that are essential for the viability, movement, or fertility of the animals. We used neuronally enhanced feeding RNA interference to screen genes that cause lethality or paralysis when mutated, and we identified 61 such genes affecting touch sensitivity, including five positive controls. We confirmed 18 genes by using available alleles, and further studied one of them, tag-170, now renamed txdc-9. txdc-9 preferentially affects anterior touch response but is needed for tubulin acetylation and microtubule formation in both the anterior and posterior touch receptor neurons. Our results indicate that neuronally enhanced feeding RNA interference screens complement traditional mutageneses by identifying additional nonviable genes needed for specific neuronal functions.

scholarly journals Comparing Caenorhabditis elegans gentle and harsh touch response behavior using a multiplexed hydraulic microfluidic device

2017 ◽  
Author(s):  
Patrick D. McClanahan ◽  
Joyce H. Xu ◽  
Christopher Fang-Yen
Keyword(s):  
Caenorhabditis Elegans ◽  
Microfluidic Device ◽  
Receptive Fields ◽  
The Body ◽  
Mechanical Stimuli ◽  
C Elegans ◽  
Response Characteristics ◽  
Touch Receptor Neurons ◽  
Touch Response ◽  
Receptor Neurons

AbstractThe roundworm Caenorhabditis elegans is an important model system for understanding the genetics and physiology of touch. Classical assays for C. elegans touch, which involve manually touching the animal with a probe and observing its response, are limited by their low throughput and qualitative nature. We developed a microfluidic device in which several dozen animals are subject to spatially localized mechanical stimuli with variable amplitude. The device contains 64 sinusoidal channels through which worms crawl, and hydraulic valves that deliver touch stimuli to the worms. We used this assay to characterize the behavioral responses to gentle touch stimuli and the less well studied harsh (nociceptive) touch stimuli. First, we measured the relative response thresholds of gentle and harsh touch. Next, we quantified differences in the receptive fields between wild type worms and a mutant with non-functioning posterior touch receptor neurons. We showed that under gentle touch the receptive field of the anterior touch receptor neurons extends into the posterior half of the body. Finally, we found that the behavioral response to gentle touch does not depend on the locomotion of the animal immediately prior to the stimulus, but does depend on the location of the previous touch. Responses to harsh touch, on the other hand, did not depend on either previous velocity or stimulus location. Differences in gentle and harsh touch response characteristics may reflect the different innervation of the respective mechanosensory cells. Our assay will facilitate studies of mechanosensation, sensory adaptation, and nociception.

scholarly journals Structural and functional diversity in the neuronal microtubules of Caenorhabditis elegans.

1982 ◽  
Vol 93 (1) ◽  
pp. 15-23 ◽  
Author(s):  
M Chalfie ◽  
J N Thomson
Keyword(s):  
Caenorhabditis Elegans ◽  
Colchicine Treatment ◽  
Variable Number ◽  
Sensory Transduction ◽  
Partial Replacement ◽  
C Elegans ◽  
Touch Receptor Neurons ◽  
Touch Sensitivity ◽  
Receptor Neurons

Tannic acid fixation reveals differences in the number of protofilaments between microtubules (MTs) in the nematode Caenorhabditis elegans. Most cells have MTs with 11 protofilaments but the six touch receptor neurons (the microtubule cells) have MTs with 15 protofilaments. No 13-protofilament (13-p) MT has been seen. The modified cilia of sensory neurons also possess unusual structures. The cilia contain nine outer doublets with A subfibers of 13 protofilaments and B subfibers of 11 protofilaments and a variable number of inner singlet MTs containing 11 protofilaments. The 15-p MTs but not the 11-p MTs are eliminated by colchicine-treatment or by mutation of the gene mec-7. Concomitantly, touch sensitivity is also lost. However, whereas colchicine treatment leads to the loss of all MTs from the microtubule cells, mutations in mec-7 result in the partial replacement of the 15-p MTs with 11-p MTs. Benzimidazoles (benomyl and nocodazole) have more general effects on C. elegans (slow growth, severe uncoordination, and loss of processes from the ventral cord) but do not affect the 15-p MTs. Benomyl will, however, disrupt the replacement 11-p MTs found in the microtubule cells of mec-7 mutants. The 11-p and 15-p MTs also respond differently to temperature and fixation conditions. It is likely that either type of MT will suffice for the proper outgrowth of the microtubule cell process, but only the 15-p MT can function in the specialized role of sensory transduction of the microtubule cells.

scholarly journals Multiple Subunits of the Caenorhabditis elegans Anaphase-Promoting Complex Are Required for Chromosome Segregation During Meiosis I

Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 805-813 ◽  
Author(s):  
Edward S Davis ◽  
Lucia Wille ◽  
Barry A Chestnut ◽  
Penny L Sadler ◽  
Diane C Shakes ◽  
...  
Keyword(s):  
Rna Interference ◽  
Caenorhabditis Elegans ◽  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Sister Chromatid Cohesion ◽  
Anaphase Promoting Complex ◽  
Genetic Screens ◽  
Chromatid Cohesion ◽  
Interference Studies ◽  
Meiosis I

Abstract Two genes, originally identified in genetic screens for Caenorhabditis elegans mutants that arrest in metaphase of meiosis I, prove to encode subunits of the anaphase-promoting complex or cyclosome (APC/C). RNA interference studies reveal that these and other APC/C subunits are essential for the segregation of chromosomal homologs during meiosis I. Further, chromosome segregation during meiosis I requires APC/C functions in addition to the release of sister chromatid cohesion.

scholarly journals Distinct roles for innexin gap junctions and hemichannels in mechanosensation

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Denise S Walker ◽  
William R Schafer
Keyword(s):  
Blood Pressure ◽  
Heterologous Expression ◽  
Pain Perception ◽  
Mechanosensory Transduction ◽  
Wide Range ◽  
Touch Receptor Neurons ◽  
Touch Sensitivity ◽  
Range Of Functions ◽  
Receptor Neurons ◽  
And Control

Mechanosensation is central to a wide range of functions, including tactile and pain perception, hearing, proprioception, and control of blood pressure, but identifying the molecules underlying mechanotransduction has proved challenging. In Caenorhabditis elegans, the avoidance response to gentle body touch is mediated by six touch receptor neurons (TRNs), and is dependent on MEC-4, a DEG/ENaC channel. We show that hemichannels containing the innexin protein UNC-7 are also essential for gentle touch in the TRNs, as well as harsh touch in both the TRNs and the PVD nociceptors. UNC-7 and MEC-4 do not colocalize, suggesting that their roles in mechanosensory transduction are independent. Heterologous expression of unc-7 in touch-insensitive chemosensory neurons confers ectopic touch sensitivity, indicating a specific role for UNC-7 hemichannels in mechanosensation. The unc-7 touch defect can be rescued by the homologous mouse gene Panx1 gene, thus, innexin/pannexin proteins may play broadly conserved roles in neuronal mechanotransduction.

scholarly journals Distinct roles for innexin gap junctions and hemichannels in mechanosensation

2019 ◽  
Author(s):  
Denise S. Walker ◽  
William R. Schafer
Keyword(s):  
Blood Pressure ◽  
Pain Perception ◽  
Direct Role ◽  
Mechanosensory Transduction ◽  
Wide Range ◽  
Touch Receptor Neurons ◽  
Touch Sensitivity ◽  
Range Of Functions ◽  
Receptor Neurons ◽  
And Control

AbstractMechanosensation is central to a wide range of functions, including tactile and pain perception, hearing, proprioception, and control of blood pressure, but identifying the molecules underlying mechanotransduction has proved challenging. In Caenorhabditis elegans, the avoidance response to gentle body touch is mediated by 6 touch receptor neurons (TRNs), and is dependent on MEC-4, a DEG/ENaC channel. We show that hemichannels containing the innexin protein UNC-7 are also essential for gentle touch in the TRNs, as well as harsh touch in both the TRNs and the PVD nociceptors. UNC-7 and MEC-4 do not colocalize, suggesting that their roles in mechanosensory transduction are independent. Heterologous expression of unc-7 in touch-insensitive chemosensory neurons confers ectopic touch sensitivity, indicating a direct role for UNC-7 hemichannels in mechanosensation. The unc-7 touch defect can be rescued by the homologous mouse gene Panx1 gene, thus, innexin/pannexin proteins may play broadly conserved roles in neuronal mechanotransduction.

scholarly journals Subunit composition of a DEG/ENaC mechanosensory channel of Caenorhabditis elegans

2015 ◽  
Vol 112 (37) ◽  
pp. 11690-11695 ◽  
Author(s):  
Yushu Chen ◽  
Shashank Bharill ◽  
Ehud Y. Isacoff ◽  
Martin Chalfie
Keyword(s):  
Caenorhabditis Elegans ◽  
Sodium Channel ◽  
Optical Imaging ◽  
Single Molecule ◽  
The Core ◽  
Touch Receptor Neurons ◽  
Receptor Neurons ◽  
Vitro Data ◽  
In Vitro Data

Caenorhabditis elegans senses gentle touch in the six touch receptor neurons (TRNs) using a mechanotransduction complex that contains the pore-forming degenerin/epithelial sodium channel (DEG/ENaC) proteins MEC-4 and MEC-10. Past work has suggested these proteins interact with the paraoxonase-like MEC-6 and the cholesterol-binding stomatin-like MEC-2 proteins. Using single molecule optical imaging in Xenopus oocytes, we found that MEC-4 forms homotrimers and MEC-4 and MEC-10 form 4:4:10 heterotrimers. MEC-6 and MEC-2 do not associate tightly with these trimers and do not influence trimer stoichiometry, indicating that they are not part of the core channel transduction complex. Consistent with the in vitro data, MEC-10, but not MEC-6, formed puncta in TRN neurites that colocalize with MEC-4 when MEC-4 is overexpressed in the TRNs.

scholarly journals The DEG/ENaC Protein MEC-10 Regulates the Transduction Channel Complex in Caenorhabditis elegans Touch Receptor Neurons

2011 ◽  
Vol 31 (35) ◽  
pp. 12695-12704 ◽  
Author(s):  
J. Arnadottir ◽  
R. O'Hagan ◽  
Y. Chen ◽  
M. B. Goodman ◽  
M. Chalfie
Keyword(s):  
Caenorhabditis Elegans ◽  
Touch Receptor Neurons ◽  
Receptor Neurons
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