scholarly journals Microtubule-dependent ribosome localization in C. elegans neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Kentaro Noma ◽  
Alexandr Goncharov ◽  
Mark H Ellisman ◽  
Yishi Jin

Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons.

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 317-330 ◽  
Author(s):  
O. Bossinger ◽  
E. Schierenberg

The pattern of autofluorescence in the two free-living namatodes Rhabditis dolichura and Caenorhabditis compared. In C. elegans, during later embryogenesis cells develop a typical bluish autofluorescence as illumination, while in Rh. dolichura a strong already present in the unfertilized egg. Using a new,


2020 ◽  
Vol 21 (14) ◽  
pp. 4859
Author(s):  
Taejoon Kim ◽  
Bokyeong Song ◽  
Im-Soon Lee

Glial cells are key players in the proper formation and maintenance of the nervous system, thus contributing to neuronal health and disease in humans. However, little is known about the molecular pathways that govern glia–neuron communications in the diseased brain. Drosophila provides a useful in vivo model to explore the conserved molecular details of glial cell biology and their contributions to brain function and disease susceptibility. Herein, we review recent studies that explore glial functions in normal neuronal development, along with Drosophila models that seek to identify the pathological implications of glial defects in the context of various central nervous system disorders.


2016 ◽  
Author(s):  
Cristina Aguirre-Chen ◽  
Nuri Kim ◽  
Olivia Mendivil Ramos ◽  
Melissa Kramer ◽  
W. Richard McCombie ◽  
...  

AbstractOne of the primary challenges in the field of psychiatric genetics is the lack of an in vivo model system in which to functionally validate candidate neuropsychiatric risk genes (NRGs) in a rapid and cost-effective manner1−3. To overcome this obstacle, we performed a candidate-based RNAi screen in which C. elegans orthologs of human NRGs were assayed for dendritic arborization and cell specification defects using C. elegans PVD neurons. Of 66 NRGs, identified via exome sequencing of autism (ASD)4 or schizophrenia (SCZ)5−9 probands and whose mutations are de novo and predicted to result in a complete or partial loss of protein function, the C. elegans orthologs of 7 NRGs were found to be required for proper neuronal development and represent a variety of functional classes, including transcriptional regulators and chromatin remodelers, molecular chaperones, and cytoskeleton-related proteins. Notably, the positive hit rate, when selectively assaying C. elegans orthologs of ASD and SCZ NRGs, is enriched >14-fold as compared to unbiased RNAi screening10. Furthermore, we find that RNAi phenotypes associated with the depletion of NRG orthologs is recapitulated in genetic mutant animals, and, via genetic interaction studies, we show that the NRG ortholog of ANK2, unc-44, is required for SAX-7/MNR-1/DMA-1 signaling. Collectively, our studies demonstrate that C. elegans PVD neurons are a tractable model in which to discover and dissect the fundamental molecular mechanisms underlying neuropsychiatric disease pathogenesis.


2018 ◽  
Author(s):  
Jason S. Watts ◽  
Henry F. Harrison ◽  
Shizue Omi ◽  
Quentin Guenthers ◽  
James Dalelio ◽  
...  

AbstractRNA interference is a powerful tool for dissecting gene function. In Caenorhabditis elegans, ingestion of double stranded RNA causes strong, systemic knockdown of target genes. Further insight into gene function can be revealed by tissue-specific RNAi techniques. Currently available tissue-specific C. elegans strains rely on rescue of RNAi function in a desired tissue or cell in an otherwise RNAi deficient genetic background. We attempted to assess the contribution of specific tissues to polyunsaturated fatty acid (PUFA) synthesis using currently available tissue-specific RNAi strains. We discovered that rde-1 (ne219), a commonly used RNAi-resistant mutant strain, retains considerable RNAi capacity against RNAi directed at PUFA synthesis genes. By measuring changes in the fatty acid products of the desaturase enzymes that synthesize PUFAs, we found that the before mentioned strain, rde-1 (ne219) and the reported germline only RNAi strain, rrf-1 (pk1417) are not appropriate genetic backgrounds for tissue-specific RNAi experiments. However, the knockout mutant rde-1 (ne300) was strongly resistant to dsRNA induced RNAi, and thus is more appropriate for construction of a robust tissue-specific RNAi strains. Using newly constructed strains in the rde-1(null) background, we found considerable desaturase activity in intestinal, epidermal, and germline tissues, but not in muscle. The RNAi-specific strains reported in this study will be useful tools for C. elegans researchers studying a variety of biological processes.


2021 ◽  
Author(s):  
Ian Daniel Wolff ◽  
Jeremy Alden Hollis ◽  
Sarah Marie Wignall

During the meiotic divisions in oocytes, microtubules are sorted and organized by motor proteins to generate a bipolar spindle in the absence of centrosomes. In most organisms, kinesin-5 family members crosslink and slide microtubules to generate outward force that promotes acentrosomal spindle bipolarity. However, the mechanistic basis for how other kinesin families act on acentrosomal spindles has not been explored. We investigated this question in C. elegans oocytes, where kinesin-5 is not required to generate outward force. Instead, the kinesin-12 family motor KLP-18 performs this function. KLP-18 acts with adaptor protein MESP-1 (meiotic spindle 1) to sort microtubule minus ends to the periphery of a microtubule array, where they coalesce into spindle poles. If either of these proteins is depleted, outward sorting of microtubules is lost and minus ends converge to form a monoaster. Here we use a combination of in vitro biochemical assays and in vivo mutant analysis to provide insight into the mechanism by which these proteins collaborate to promote acentrosomal spindle assembly. We identify a microtubule binding site on the C-terminal stalk of KLP-18 and demonstrate that a direct interaction between the KLP-18 stalk and MESP-1 activates non-motor microtubule binding. We also provide evidence that this C-terminal domain is required for KLP-18 activity during spindle assembly and show that KLP-18 is continuously required to maintain spindle bipolarity. This study thus provides new insight into the construction and maintenance of the oocyte acentrosomal spindle as well as into kinesin-12 mechanism and regulation.


2018 ◽  
Author(s):  
Lewie Zeng ◽  
Rachid El Bejjani ◽  
Marc Hammarlund

AbstractMembers of the Amyloid Precursor Protein (APP) family have important functions during neuronal development. However, their physiological functions in the mature nervous system are not fully understood. Here we use the C. elegans GABAergic motor neurons to study the post-developmental function of the APP-like protein APL-1 in vivo. We find that apl-1 has minimum roles in the maintenance of gross neuron morphology and function. However, we show that apl-1 is an inhibitor of axon regeneration, acting on mature neurons to limit regrowth in response to injury. The small GTPase Rab6/RAB-6.2 also inhibits regeneration, and does so in part by maintaining protein levels of APL-1. To inhibit regeneration, APL-1 functions via the E2 domain of its ectodomain; the cytoplasmic tail, transmembrane anchoring, and the E1 domain are not required for this function. Our data defines a novel role for APL-1 in modulating the neuronal response to injury.


Author(s):  
Matthew G. Andrusiak ◽  
Yishi Jin

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yong Zhang ◽  
Ke Wang ◽  
Kanglong Yang ◽  
Yunyu Shi ◽  
Jingjun Hong

AbstractPrevious studies indicated that the P-body components, CGH-1 and EDC-3 may play a crucial role in the regulation of lifespan in Caenorhabditis elegans. Homo sapiens DDX6 or Saccharomyces cerevisiae Dhh1p (CGH-1 in C. elegans) could form complexes with EDC3 (Edc3p in yeast), respectively, which is significant for translation inhibition and mRNA decay. However, it is currently unclear how CGH-1 can be recognized by EDC-3 in C. elegans. Here, we provided structural and biochemical insights into the interaction between CGH-1 and EDC-3. Combined with homology modeling, mutation, and ITC assays, we uncovered an interface between CGH-1 RecA2 domain and EDC-3 FDF-FEK. Additionally, GST-pulldown and co-localization experiments confirmed the interaction between CGH-1 and EDC-3 in vitro and in vivo. We also analyzed PATR-1-binding interface on CGH-1 RecA2 by ITC assays. Moreover, we unveiled the similarity and differences of the binding mode between EDC-3 and CAR-1 or PATR-1. Taken together, these findings provide insights into the recognition of DEAD-box protein CGH-1 by EDC-3 FDF-FEK motif, suggesting important functional implications.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Kasturi Chakraborty ◽  
Palapuravan Anees ◽  
Sunaina Surana ◽  
Simona Martin ◽  
Jihad Aburas ◽  
...  

Nucleic acid nanodevices present great potential as agents for logic-based therapeutic intervention as well as in basic biology. Often, however, the disease targets that need corrective action are localized in specific organs and thus realizing the full potential of DNA nanodevices also requires ways to target them to specific cell-types in vivo. Here we show that by exploiting either endogenous or synthetic receptor-ligand interactions and by leveraging the biological barriers presented by the organism, we can target extraneously introduced DNA nanodevices to specific cell types in C. elegans, with sub-cellular precision. The amenability of DNA nanostructures to tissue-specific targeting in vivo significantly expands their utility in biomedical applications and discovery biology.


2020 ◽  
Author(s):  
João J. Ramalho ◽  
Ophélie Nicolle ◽  
Grégoire Michaux ◽  
Mike Boxem

AbstractERM proteins are conserved regulators of cortical membrane specialization, that function as membrane–actin linkers and molecular hubs. Activity of ERM proteins requires a conformational switch from an inactive cytoplasmic form into an active membrane- and actin-bound form, which is thought to be mediated by sequential PIP2-binding and phosphorylation of a conserved C-terminal threonine residue. Here, we use the single C. elegans ERM ortholog, ERM-1, to study the contribution of these regulatory events to ERM activity and tissue formation in vivo. Using CRISPR/Cas9-generated erm-1 mutant alleles we demonstrate that PIP2-binding is critically required for ERM-1 function. In contrast, dynamic regulation of C-terminal T544 phosphorylation is not essential but modulates ERM-1 apical localization and dynamics in a tissue-specific manner, to control cortical actin organization and drive lumen formation in epithelial tubes. Our work highlights the dynamic nature of ERM protein regulation during tissue morphogenesis and the importance of C-terminal phosphorylation in fine-tuning ERM activity in a tissue-specific context.


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