Sensory activity affects sensory axon development in C. elegans

Development ◽  
1999 ◽  
Vol 126 (9) ◽  
pp. 1891-1902 ◽  
Author(s):  
E.L. Peckol ◽  
J.A. Zallen ◽  
J.C. Yarrow ◽  
C.I. Bargmann
Keyword(s):  
Nervous System ◽  
Molecular Mechanisms ◽  
Sensory Deprivation ◽  
Axon Growth ◽  
System Structure ◽  
Sensory Axon ◽  
C Elegans ◽  
Sensory Axons ◽  
Axon Development ◽  
Sensory Activity

The simple nervous system of the nematode C. elegans consists of 302 neurons with highly reproducible morphologies, suggesting a hard-wired program of axon guidance. Surprisingly, we show here that sensory activity shapes sensory axon morphology in C. elegans. A class of mutants with deformed sensory cilia at their dendrite endings have extra axon branches, suggesting that sensory deprivation disrupts axon outgrowth. Mutations that alter calcium channels or membrane potential cause similar defects. Cell-specific perturbations of sensory activity can cause cell-autonomous changes in axon morphology. Although the sensory axons initially reach their targets in the embryo, the mutations that alter sensory activity cause extra axon growth late in development. Thus, perturbations of activity affect the maintenance of sensory axon morphology after an initial pattern of innervation is established. This system provides a genetically tractable model for identifying molecular mechanisms linking neuronal activity to nervous system structure.

scholarly journals Inhibition of PTEN activity promotes IB4-positive sensory neuronal axon growth

2020 ◽  
Author(s):  
Li-Yu Zhou ◽  
Feng Han ◽  
Shi-Bin Qi ◽  
Jin-Jin Ma ◽  
Yan-Xia Ma ◽  
...  
Keyword(s):  
Nervous System ◽  
Sensory Neurons ◽  
Strong Evidence ◽  
Axon Regeneration ◽  
Axon Growth ◽  
Clinical Problem ◽  
Sensory Axon ◽  
Nerve Injuries ◽  
Critical Process ◽  
Common Clinical Problem

AbstractTraumatic nerve injuries have become a common clinical problem, and axon regeneration is a critical process in the successful functional recovery of the injured nervous system. In this study, we found that peripheral axotomy reduce total PTEN expression in adult sensory neurons, however, it did not alter the expression level of PTEN in IB4-positive sensory neurons. Additionally, our results indicate that the artificial inhibition of PTEN markedly promotes adult sensory axon regeneration, including IB4-positive neuronal axon growth. Thus, our results provide strong evidence that PTEN is a prominent repressor of adult sensory axon regeneration, especially in IB4-positive neurons.

scholarly journals Transmembrane Collagens in Neuromuscular Development and Disorders

2021 ◽  
Vol 13 ◽  
Author(s):  
Tomoko Wakabayashi
Keyword(s):  
Molecular Mechanisms ◽  
Neuromuscular Junctions ◽  
Transmembrane Protein ◽  
Axon Growth ◽  
Congenital Myasthenic Syndrome ◽  
Loss Of Function ◽  
C Elegans ◽  
Ocular Motor Disorders ◽  
Multistep Process ◽  
Neuromuscular Development

Neuromuscular development is a multistep process and involves interactions among various extracellular and transmembrane molecules that facilitate the precise targeting of motor axons to synaptogenic regions of the target muscle. Collagenous proteins with transmembrane domains have recently emerged as molecules that play essential roles in multiple aspects of neuromuscular formation. Membrane-associated collagens with interrupted triple helices (MACITs) are classified as an unconventional subtype of the collagen superfamily and have been implicated in cell adhesion in a variety of tissues, including the neuromuscular system. Collagen XXV, the latest member of the MACITs, plays an essential role in motor axon growth within the developing muscle. In humans, loss-of-function mutations of collagen XXV result in developmental ocular motor disorders. In contrast, collagen XIII contributes to the formation and maintenance of neuromuscular junctions (NMJs), and disruption of its function leads to the congenital myasthenic syndrome. Transmembrane collagens are conserved not only in mammals but also in organisms such as C. elegans, where a single MACIT, COL-99, has been documented to function in motor innervation. Furthermore, in C. elegans, a collagen-like transmembrane protein, UNC-122, is implicated in the structural and functional integrity of the NMJ. This review article summarizes recent advances in understanding the roles of transmembrane collagens and underlying molecular mechanisms in multiple aspects of neuromuscular development and disorders.

Multiple Roles of RNA Regulatory Factors in Neuronal Development and Function in C. elegans

2020 ◽  
Author(s):  
Matthew G. Andrusiak ◽  
Yishi Jin
Keyword(s):  
Nervous System ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Model Organism ◽  
Nervous System Development ◽  
Forward Genetics ◽  
C Elegans

Recent evidence has highlighted the dynamic nature of mRNA regulation, particularly in the nervous system, from complex pre-mRNA processing to long-range transport and long-term storage of mature mRNAs. In accordance with the importance for mRNA-mediated regulation of nervous system development and maintenance, various mutations in RNA-binding proteins are associated with a range of human disorders. C. elegans express many RNA-binding factors that have human orthologs and perform similar biochemical functions. This chapter focuses on the research using C. elegans to dissect molecular mechanisms involving mRNA-mediated pathways. It highlights the key approaches and findings that integrate genetic and genomic studies in the nervous system. The analyses of genetic mutants, primarily using forward genetics, offer functional insights for genes important for neuronal development, synaptic transmission, and neuronal repair. In combination with single-neuron cell biology and cell-type genomics, the knowledge learned from this model organism has continued to lead to ground-breaking discoveries.

scholarly journals Distinct cellular and molecular mechanisms mediate initial axon development and adult-stage axon regeneration in C. elegans

Development ◽  
2008 ◽  
Vol 135 (21) ◽  
pp. 3623-3623 ◽  
Author(s):  
C. V. Gabel ◽  
F. Antoine ◽  
C.-F. Chuang ◽  
A. D. T. Samuel ◽  
C. Chang
Keyword(s):  
Molecular Mechanisms ◽  
Axon Regeneration ◽  
Adult Stage ◽  
C Elegans ◽  
Axon Development

scholarly journals Distinct cellular and molecular mechanisms mediate initial axon development and adult-stage axon regeneration in C. elegans

Development ◽  
2008 ◽  
Vol 135 (6) ◽  
pp. 1129-1136 ◽  
Author(s):  
C. V. Gabel ◽  
F. Antoine ◽  
C.-F. Chuang ◽  
A. D. T. Samuel ◽  
C. Chang
Keyword(s):  
Molecular Mechanisms ◽  
Axon Regeneration ◽  
Adult Stage ◽  
C Elegans ◽  
Axon Development

scholarly journals An autism-associated calcium channel variant causes defects in neuronal polarity and axon termination in the ALM neuron of C. elegans

2020 ◽  
Author(s):  
Tyler Buddell ◽  
Christopher C. Quinn
Keyword(s):  
Calcium Channel ◽  
Neurodevelopmental Disorders ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Neuronal Polarity ◽  
Timothy Syndrome ◽  
C Elegans ◽  
Axon Development ◽  
Axon Termination ◽  
Axonal Defects

AbstractVariants of the CACNA1C voltage-gated calcium channel gene have been associated with autism and other neurodevelopmental disorders including bipolar disorder, schizophrenia, and ADHD. The Timothy syndrome mutation is a rare de novo gain-of-function variant in CACNA1C that causes autism with high penetrance, providing a powerful avenue into investigating the role of CACNA1C variants in neurodevelopmental disorders. In our previous work, we demonstrated that an egl-19(gof) mutation, that is equivalent to the Timothy syndrome mutation in the human homolog CACNA1C, can disrupt termination of the PLM axon in C. elegans. Here, we find that the egl-19(gof) mutation disrupts the polarity of process outgrowth in the ALM neuron of C. elegans. We also find that the egl-19(gof) mutation can disrupt termination of the ALM axon. These results suggest that the Timothy syndrome mutation can disrupt multiple steps of axon development. Further work exploring the molecular mechanisms that underlie these perturbations in neuronal polarity and axon termination will give us better understanding to how variants in CACNA1C contribute to the axonal defects that underlie autism.

scholarly journals Regulation of Gliogenesis by lin-32/Atoh1 in Caenorhabditis elegans

2020 ◽  
Vol 10 (9) ◽  
pp. 3271-3278 ◽  
Author(s):  
Albert Zhang ◽  
Kentaro Noma ◽  
Dong Yan
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Embryonic Development ◽  
Molecular Mechanisms ◽  
System Development ◽  
Nervous System Development ◽  
Proneural Gene ◽  
C Elegans ◽  
Fundamental Process ◽  
Mutant Phenotypes

Abstract The regulation of gliogenesis is a fundamental process for nervous system development, as the appropriate glial number and identity is required for a functional nervous system. To investigate the molecular mechanisms involved in gliogenesis, we used C. elegans as a model and identified the function of the proneural gene lin-32/Atoh1 in gliogenesis. We found that lin-32 functions during embryonic development to negatively regulate the number of AMsh glia. The ectopic AMsh cells at least partially arise from cells originally fated to become CEPsh glia, suggesting that lin-32 is involved in the specification of specific glial subtypes. Moreover, we show that lin-32 acts in parallel with cnd-1/ NeuroD1 and ngn-1/ Neurog1 in negatively regulating an AMsh glia fate. Furthermore, expression of murine Atoh1 fully rescues lin-32 mutant phenotypes, suggesting lin-32/Atoh1 may have a conserved role in glial specification.

scholarly journals Neuronally Produced Betaine Acts via a Novel Ligand Gated Ion Channel to Control Behavioural States

2021 ◽  
Author(s):  
Iris Hardege ◽  
Julia Morud ◽  
Jingfang Yu ◽  
Tatiana S Wilson ◽  
Frank Schroeder ◽  
...  
Keyword(s):  
Nervous System ◽  
Ion Channel ◽  
Molecular Mechanisms ◽  
Amino Acid Derivative ◽  
Single Pair ◽  
Complex Behaviour ◽  
Functional Roles ◽  
C Elegans ◽  
Nematode Worm ◽  
Control Complex

Trimethyl glycine, or betaine, is an amino acid derivative found in diverse organisms, from bacteria to plants and animals. It can function as an osmolyte to protect cells against osmotic stress, and building evidence suggests betaine may also play important functional roles in the nervous system. However, despite growing interest in betaine's roles in the nervous system, few molecular mechanisms have been elucidated. Here we identify the expression of betaine synthesis pathway genes in the nervous system of the nematode worm, C. elegans. We show that betaine, produced in a single pair of interneurons, the RIMs, can control complex behavioural states. Moreover, we also identify and characterise a new betaine-gated inhibitory ligand gated ion channel, LGC-41, which is required for betaine related behavioural changes. Intriguingly we observed expression of LGC-41 in punctate structures across several sensory and interneurons, including those synaptically connected to the RIMs. Our data presents a neuronal molecular mechanism for the action of betaine, via a specific receptor, in the control of complex behaviour within the nervous system of C. elegans. This may suggest a much broader role for betaine in the regulation of animal nervous systems than previously recognised.

scholarly journals Conserved gene regulatory module specifies lateral neural borders across bilaterians

2017 ◽  
Vol 114 (31) ◽  
pp. E6352-E6360 ◽  
Author(s):  
Yongbin Li ◽  
Di Zhao ◽  
Takeo Horie ◽  
Geng Chen ◽  
Hongcun Bao ◽  
...  
Keyword(s):  
Nervous System ◽  
Molecular Mechanisms ◽  
Neural Progenitors ◽  
Expression Domain ◽  
Lateral Border ◽  
C Elegans ◽  
Regulatory Module ◽  
Neural Plate Border ◽  
Gene Regulatory ◽  
Conserved Gene

The lateral neural plate border (NPB), the neural part of the vertebrate neural border, is composed of central nervous system (CNS) progenitors and peripheral nervous system (PNS) progenitors. In invertebrates, PNS progenitors are also juxtaposed to the lateral boundary of the CNS. Whether there are conserved molecular mechanisms determining vertebrate and invertebrate lateral neural borders remains unclear. Using single-cell-resolution gene-expression profiling and genetic analysis, we present evidence that orthologs of the NPB specification module specify the invertebrate lateral neural border, which is composed of CNS and PNS progenitors. First, like in vertebrates, the conserved neuroectoderm lateral border specifier Msx/vab-15 specifies lateral neuroblasts in Caenorhabditis elegans. Second, orthologs of the vertebrate NPB specification module (Msx/vab-15, Pax3/7/pax-3, and Zic/ref-2) are significantly enriched in worm lateral neuroblasts. In addition, like in other bilaterians, the expression domain of Msx/vab-15 is more lateral than those of Pax3/7/pax-3 and Zic/ref-2 in C. elegans. Third, we show that Msx/vab-15 regulates the development of mechanosensory neurons derived from lateral neural progenitors in multiple invertebrate species, including C. elegans, Drosophila melanogaster, and Ciona intestinalis. We also identify a novel lateral neural border specifier, ZNF703/tlp-1, which functions synergistically with Msx/vab-15 in both C. elegans and Xenopus laevis. These data suggest a common origin of the molecular mechanism specifying lateral neural borders across bilaterians.

scholarly journals Autophagy is required for midbrain dopaminergic axon development and their responsiveness to guidance cues

2020 ◽  
Author(s):  
M.S. Profes ◽  
A. Saghatelyan ◽  
M. Lévesque
Keyword(s):  
Molecular Mechanisms ◽  
Axon Growth ◽  
Brain Functions ◽  
Guidance Cues ◽  
Axon Development ◽  
Wide Range ◽  
Growth Guidance ◽  
Circuit Formation

AbstractMesodiencephalic dopamine (mDA) neurons play a wide range of brain functions. Distinct subtypes of mDA neurons regulate these functions but the molecular mechanisms that drive the mDA circuit formation are largely unknown. Here we show that autophagy, the main recycling cellular pathway, is present in the growth cones of developing mDA neurons and its level changes dynamically in response to guidance cues. To characterize the role of autophagy in mDA axon growth/guidance, we knocked-out (KO) essential autophagy genes (Atg12, Atg5) in mice mDA neurons. Autophagy deficient mDA axons exhibit axonal swellings and decreased branching both in vitro and in vivo, likely due to aberrant microtubule looping. Strikingly, deletion of autophagy-related genes, blunted completely the response of mDA neurons to chemo-repulsive and chemo-attractive guidance cues. Our data demonstrate that autophagy plays a central role in regulating mDA neurons development, orchestrating axonal growth and guidance.

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