scholarly journals ENU-3 is a novel outgrowth and guidance protein in c. elegans

2021 ◽  
Author(s):  
Callista Stephanie Yee
Keyword(s):  
Amino Acids ◽  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Membrane Protein ◽  
Motor Neuron ◽  
Gene Product ◽  
Motor Neurons ◽  
Growth Cones ◽  
C Elegans ◽  
Extracellular Molecules

During the development of the nervous system, the migration of many cells and axons is guided by extracellular molecules. These molecules bind to receptors at the tips of the growth cones of migrating axons and trigger intracellular signalling to steer the axons along the correct trajectories. Previous work has identified a novel mutant, enu-3 (enhancer of Unc), that enhances the motor neuron axon outgrowth defects observed in strains of Caenorhabditis elegans that lack either the UNC-5 receptor or its ligand UNC-6/Netrin, enu-3 single mutants have weak motor neuron axon migration defects. Both outgrowth defects of double mutants and axon migration defects of enu-3 mutants were rescued by expression of the H04D03.1 gene product. Enu-3/H04D03.1 encodes a novel predicted putative trans-membrane protein of 204 amino acids. ENU-3 is expressed weakly expressed in many cell bodies along the ventral cord, including those of the DA and DB motor neurons.

scholarly journals ENU-3 is a novel outgrowth and guidance protein in c. elegans

2021 ◽  
Author(s):  
Callista Stephanie Yee
Keyword(s):  
Amino Acids ◽  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Membrane Protein ◽  
Motor Neuron ◽  
Gene Product ◽  
Motor Neurons ◽  
Growth Cones ◽  
C Elegans ◽  
Extracellular Molecules

During the development of the nervous system, the migration of many cells and axons is guided by extracellular molecules. These molecules bind to receptors at the tips of the growth cones of migrating axons and trigger intracellular signalling to steer the axons along the correct trajectories. Previous work has identified a novel mutant, enu-3 (enhancer of Unc), that enhances the motor neuron axon outgrowth defects observed in strains of Caenorhabditis elegans that lack either the UNC-5 receptor or its ligand UNC-6/Netrin, enu-3 single mutants have weak motor neuron axon migration defects. Both outgrowth defects of double mutants and axon migration defects of enu-3 mutants were rescued by expression of the H04D03.1 gene product. Enu-3/H04D03.1 encodes a novel predicted putative trans-membrane protein of 204 amino acids. ENU-3 is expressed weakly expressed in many cell bodies along the ventral cord, including those of the DA and DB motor neurons.

scholarly journals Integrins Have Cell-Type-Specific Roles in the Development of Motor Neuron Connectivity

2019 ◽  
Vol 7 (3) ◽  
pp. 17 ◽  
Author(s):  
Devyn Oliver ◽  
Emily Norman ◽  
Heather Bates ◽  
Rachel Avard ◽  
Monika Rettler ◽  
...  
Keyword(s):  
Nervous System ◽  
Cell Adhesion ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Neuron Development ◽  
Wild Type ◽  
Cell Type ◽  
C Elegans ◽  
Cell Type Specific ◽  
Two Phases

Formation of the nervous system requires a complex series of events including proper extension and guidance of neuronal axons and dendrites. Here we investigate the requirement for integrins, a class of transmembrane cell adhesion receptors, in regulating these processes across classes of C. elegans motor neurons. We show α integrin/ina-1 is expressed by both GABAergic and cholinergic motor neurons. Despite this, our analysis of hypomorphic ina-1(gm144) mutants indicates preferential involvement of α integrin/ina-1 in GABAergic commissural development, without obvious involvement in cholinergic commissural development. The defects in GABAergic commissures of ina-1(gm144) mutants included both premature termination and guidance errors and were reversed by expression of wild type ina-1 under control of the native ina-1 promoter. Our results also show that α integrin/ina-1 is important for proper outgrowth and guidance of commissures from both embryonic and post-embryonic born GABAergic motor neurons, indicating an ongoing requirement for integrin through two phases of GABAergic neuron development. Our findings provide insights into neuron-specific roles for integrin that would not be predicted based solely upon expression analysis.

scholarly journals A descending pathway facilitates undulatory wave propagation in Caenorhabditis elegans through gap junctions

2017 ◽  
Author(s):  
Tianqi Xu ◽  
Jing Huo ◽  
Shuai Shao ◽  
Michelle Po ◽  
Taizo Kawano ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Gap Junctions ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Central Pattern Generators ◽  
The Body ◽  
C Elegans ◽  
Bending Waves ◽  
Forward Locomotion ◽  
Type Motor

Descending signals from the brain play critical roles in controlling and modulating locomotion kinematics. In the Caenorhabditis elegans nervous system, descending AVB premotor interneurons exclusively form gap junctions with B-type motor neurons that drive forward locomotion. We combined genetic analysis, optogenetic manipulation, and computational modeling to elucidate the function of AVB-B gap junctions during forward locomotion. First, we found that some B-type motor neurons generated intrinsic rhythmic activity, constituting distributed central pattern generators. Second, AVB premotor interneurons drove bifurcation of B-type motor neuron dynamics, triggering their transition from stationary to oscillatory activity. Third, proprioceptive couplings between neighboring B-type motor neurons entrained the frequency of body oscillators, forcing coherent propagation of bending waves. Despite substantial anatomical differences between the worm motor circuit and those in higher model organisms, we uncovered converging principles that govern coordinated locomotion.Significance StatementA deep understanding of the neural basis of motor behavior must integrate neuromuscular dynamics, mechanosensory feedback, as well as global command signals, to predict behavioral dynamics. Here, we report on an integrative approach to defining the circuit logic underlying coordinated locomotion in C. elegans. Our combined experimental and computational analysis revealed that (1) motor neurons in C. elegans could function as intrinsic oscillators; (2) Descending inputs and proprioceptive couplings work synergistically to facilitate the sequential activation of motor neuron activities, allowing bending waves to propagate efficiently along the body. Our work thus represents a key step towards an integrative view of animal locomotion.

scholarly journals Analysis of the NK2 homeobox gene ceh-24 reveals sublateral motor neuron control of left-right turning during sleep

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Juliane Schwarz ◽  
Henrik Bringmann
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Three Dimensional ◽  
Homeobox Gene ◽  
Longitudinal Axis ◽  
Neural Substrates ◽  
Turning Behavior ◽  
Cholinergic Function

Sleep is a behavior that is found in all animals that have a nervous system and that have been studied carefully. In Caenorhabditis elegans larvae, sleep is associated with a turning behavior, called flipping, in which animals rotate 180° about their longitudinal axis. However, the molecular and neural substrates of this enigmatic behavior are not known. Here, we identified the conserved NK-2 homeobox gene ceh-24 to be crucially required for flipping. ceh-24 is required for the formation of processes and for cholinergic function of sublateral motor neurons, which separately innervate the four body muscle quadrants. Knockdown of cholinergic function in a subset of these sublateral neurons, the SIAs, abolishes flipping. The SIAs depolarize during flipping and their optogenetic activation induces flipping in a fraction of events. Thus, we identified the sublateral SIA neurons to control the three-dimensional movements of flipping. These neurons may also control other types of motion.

The Circuit for Chemotaxis and Exploratory Behavior in Caenorhabditis Elegans

2017 ◽  
pp. 369-376
Author(s):  
Cornelia I. Bargmann
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Neuromuscular Junctions ◽  
Wiring Diagram ◽  
C Elegans ◽  
Section Electron ◽  
Adult Hermaphrodite ◽  
Electrophysiological Characterization

A wiring diagram of the Caenorhabditis elegans nervous system was constructed from serial-section electron micrographs 30 years ago. This wiring diagram divides the 302 neurons in the nervous system of the adult hermaphrodite into three overall classes: sensory neurons, motor neurons that form neuromuscular junctions, and interneurons that connect sensory neurons with motor neurons. Most sensory neurons and interneurons belong to bilaterally symmetric pairs with similar connections and morphologies, while motor neurons belong to larger classes. The C. elegans nervous system presents an exceptional situation in which neuroanatomical connections are extremely well defined and reproducible among animals. These detailed anatomical studies and a parallel genetic attack have increasingly been joined by functional and electrophysiological characterization.

The Caenorhabditis elegans odr-2 Gene Encodes a Novel Ly-6-Related Protein Required for Olfaction

Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 211-224 ◽  
Author(s):  
Joseph H Chou ◽  
Cornelia I Bargmann ◽  
Piali Sengupta
Keyword(s):  
Caenorhabditis Elegans ◽  
Motor Neurons ◽  
Amino Terminus ◽  
Signaling Proteins ◽  
Related Protein ◽  
Olfactory Neurons ◽  
Unique Role ◽  
C Elegans ◽  
Founding Member ◽  
High Concentrations

Abstract Caenorhabditis elegans odr-2 mutants are defective in the ability to chemotax to odorants that are recognized by the two AWC olfactory neurons. Like many other olfactory mutants, they retain responses to high concentrations of AWC-sensed odors; we show here that these residual responses are caused by the ability of other olfactory neurons (the AWA neurons) to be recruited at high odor concentrations. odr-2 encodes a membrane-associated protein related to the Ly-6 superfamily of GPI-linked signaling proteins and is the founding member of a C. elegans gene family with at least seven other members. Alternative splicing of odr-2 yields three predicted proteins that differ only at the extreme amino terminus. The three isoforms have different promoters, and one isoform may have a unique role in olfaction. An epitope-tagged ODR-2 protein is expressed at high levels in sensory neurons, motor neurons, and interneurons and is enriched in axons. The AWC neurons are superficially normal in their development and structure in odr-2 mutants, but their function is impaired. Our results suggest that ODR-2 may regulate AWC signaling within the neuronal network required for chemotaxis.

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

Identification Of A Novel Gene Altered In The RQ1 Mutant Strain Affecting Motor Axon Migration In Caenorhabditis Elegans

2021 ◽  
Author(s):  
Haider Z. Naqvi
Keyword(s):  
Caenorhabditis Elegans ◽  
Axon Guidance ◽  
Motor Neurons ◽  
Genetic Background ◽  
Germ Line ◽  
Strong Indication ◽  
Wild Type ◽  
C Elegans ◽  
Novel Gene ◽  
Mutation Region

Novel genetic enhancer screens were conducted targeting mutants involved in the guidance of axons of the DA and DB classes of motor neurons in C. elegans. These mutations are expected in genes that function in parallel to the unc-g/Netrin pathway. The screen was conducted in an unc-5(e53) genetic background and enhancers of the axon guidance defects caused by the absence of UNC-5 were identified. Three mutants were previously identified in the screen called rq1, rq2 and rq3 and two additional mutants called H2-4 and M1-3, were isolated in this study. In order to identify the gene affected by the rq1 mutation, wild-type copies of genes in the mapped rq1 mutation region were injected into the mutants to rescue the phenotypic defects. This is a strong indication that the gene of interest is a novel gene called H04D03.1. Promising results indicate that the H04D03.1 protein also works in germ-line apoptosis.

scholarly journals Multifaceted roles of microRNAs: From motor neuron generation in embryos to degeneration in spinal muscular atrophy

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Tai-Heng Chen ◽  
Jun-An Chen
Keyword(s):  
Nervous System ◽  
Neurodegenerative Diseases ◽  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Cell Types ◽  
Spinal Motor Neurons ◽  
Potential Applications ◽  
The Central Nervous System

Two crucial questions in neuroscience are how neurons establish individual identity in the developing nervous system and why only specific neuron subtypes are vulnerable to neurodegenerative diseases. In the central nervous system, spinal motor neurons serve as one of the best-characterized cell types for addressing these two questions. In this review, we dissect these questions by evaluating the emerging role of regulatory microRNAs in motor neuron generation in developing embryos and their potential contributions to neurodegenerative diseases such as spinal muscular atrophy (SMA). Given recent promising results from novel microRNA-based medicines, we discuss the potential applications of microRNAs for clinical assessments of SMA disease progression and treatment.

scholarly journals Functional connectomics from neural dynamics: probabilistic graphical models for neuronal network of Caenorhabditis elegans

2018 ◽  
Vol 373 (1758) ◽  
pp. 20170377 ◽  
Author(s):  
Hexuan Liu ◽  
Jimin Kim ◽  
Eli Shlizerman
Keyword(s):  
Time Series ◽  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Graphical Models ◽  
Neuronal Network ◽  
Graphical Model ◽  
Time Series Data ◽  
Series Data ◽  
Neuronal Responses ◽  
C Elegans

We propose an approach to represent neuronal network dynamics as a probabilistic graphical model (PGM). To construct the PGM, we collect time series of neuronal responses produced by the neuronal network and use singular value decomposition to obtain a low-dimensional projection of the time-series data. We then extract dominant patterns from the projections to get pairwise dependency information and create a graphical model for the full network. The outcome model is a functional connectome that captures how stimuli propagate through the network and thus represents causal dependencies between neurons and stimuli. We apply our methodology to a model of the Caenorhabditis elegans somatic nervous system to validate and show an example of our approach. The structure and dynamics of the C. elegans nervous system are well studied and a model that generates neuronal responses is available. The resulting PGM enables us to obtain and verify underlying neuronal pathways for known behavioural scenarios and detect possible pathways for novel scenarios. This article is part of a discussion meeting issue ‘Connectome to behaviour: modelling C. elegans at cellular resolution’.

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