Intraflagellar transport motors in Caenorhabditis elegans neurons

2004 ◽  
Vol 32 (5) ◽  
pp. 682-684 ◽  
Author(s):  
J.M. Scholey ◽  
G. Ou ◽  
J. Snow ◽  
A. Gunnarson

IFT (intraflagellar transport) assembles and maintains sensory cilia on the dendritic endings of chemosensory neurons within the nematode Caenorhabditis elegans. During IFT, macromolecular protein complexes called IFT particles (which carry ciliary precursors) are moved from the base of the sensory cilium to its distal tip by anterograde IFT motors (kinesin-II and Osm-3 kinesin) and back to the base by retrograde IFT-dynein [Rosenbaum and Witman (2002) Nat. Rev. Mol. Cell Biol. 3, 813–825; Scholey (2003) Annu. Rev. Cell Dev. Biol. 19, 423–443; and Snell, Pan and Wang (2004) Cell 117, 693–697]. In the present study, we describe the protein machinery of IFT in C. elegans, which we have analysed using time-lapse fluorescence microscopy of green fluorescent protein-fusion proteins in concert with ciliary mutants.

1999 ◽  
Vol 10 (2) ◽  
pp. 345-360 ◽  
Author(s):  
Dawn Signor ◽  
Karen P. Wedaman ◽  
Lesilee S. Rose ◽  
Jonathan M. Scholey

Chemosensation in the nervous system of the nematodeCaenorhabditis elegans depends on sensory cilia, whose assembly and maintenance requires the transport of components such as axonemal proteins and signal transduction machinery to their site of incorporation into ciliary structures. Members of the heteromeric kinesin family of microtubule motors are prime candidates for playing key roles in these transport events. Here we describe the molecular characterization and partial purification of two heteromeric kinesin complexes from C. elegans, heterotrimeric CeKinesin-II and dimeric CeOsm-3. Transgenic worms expressing green fluorescent protein driven by endogenous heteromeric kinesin promoters reveal that both CeKinesin-II and CeOsm-3 are expressed in amphid, inner labial, and phasmid chemosensory neurons. Additionally, immunolocalization experiments on fixed worms show an intense concentration of CeKinesin-II and CeOsm-3 polypeptides in the ciliated endings of these chemosensory neurons and a punctate localization pattern in the corresponding cell bodies and dendrites. These results, together with the phenotypes of known mutants in the pathway of sensory ciliary assembly, suggest that CeKinesin-II and CeOsm-3 drive the transport of ciliary components required for sequential steps in the assembly of chemosensory cilia.


2002 ◽  
Vol 115 (14) ◽  
pp. 2881-2891
Author(s):  
Monika A. Jedrusik ◽  
Stefan Vogt ◽  
Peter Claus ◽  
Ekkehard Schulze

The histone H1 complement of Caenorhabditis elegans contains a single unusual protein, H1.X. Although H1.X possesses the globular domain and the canonical three-domain structure of linker histones, the amino acid composition of H1.X is distinctly different from conventional linker histones in both terminal domains. We have characterized H1.X in C. elegans by antibody labeling, green fluorescent protein fusion protein expression and RNA interference. Unlike normal linker histones, H1.X is a cytoplasmic as well as a nuclear protein and is not associated with chromosomes. H1.X is most prominently expressed in the marginal cells of the pharynx and is associated with a peculiar cytoplasmic cytoskeletal structure therein, the tonofilaments. Additionally H1.X::GFP is expressed in the cytoplasm of body and vulva muscle cells, neurons, excretory cells and in the nucleoli of embryonic blastomeres and adult gut cells. RNA interference with H1.X results in uncoordinated and egg laying defective animals, as well as in a longitudinally enlarged pharynx. These phenotypes indicate a cytoplasmic role of H1.X in muscle growth and muscle function.


2011 ◽  
Vol 22 (15) ◽  
pp. 2716-2728 ◽  
Author(s):  
Erin M. Bank ◽  
Kfir Ben-Harush ◽  
Naama Wiesel-Motiuk ◽  
Rachel Barkan ◽  
Naomi Feinstein ◽  
...  

Mutations in the human LMNA gene underlie many laminopathic diseases, including Emery-Dreifuss muscular dystrophy (EDMD); however, a mechanistic link between the effect of mutations on lamin filament assembly and disease phenotypes has not been established. We studied the ΔK46 Caenorhabditis elegans lamin mutant, corresponding to EDMD-linked ΔK32 in human lamins A and C. Cryo-electron tomography of lamin ΔK46 filaments in vitro revealed alterations in the lateral assembly of dimeric head-to-tail polymers, which causes abnormal organization of tetrameric protofilaments. Green fluorescent protein (GFP):ΔK46 lamin expressed in C. elegans was found in nuclear aggregates in postembryonic stages along with LEM-2. GFP:ΔK46 also caused mislocalization of emerin away from the nuclear periphery, consistent with a decreased ability of purified emerin to associate with lamin ΔK46 filaments in vitro. GFP:ΔK46 animals had motility defects and muscle structure abnormalities. These results show that changes in lamin filament structure can translate into disease-like phenotypes via altering the localization of nuclear lamina proteins, and suggest a model for how the ΔK32 lamin mutation may cause EDMD in humans.


2021 ◽  
Vol 9 (3) ◽  
pp. 343-352
Author(s):  
Rajul Jain ◽  
◽  
Priyanka Gautam ◽  

The ubiquitous use of pesticides all over the world leads to adverse effects on both targets as well as non-target species. The extensive and uncontrolled use of organophosphates (OPs), a large group of pesticidal compounds in agricultural and household products are resulting in high exposure to humans. This research has been carried out to study the adverse effect of OPs i.e., chlorpyrifos, trichlorfon, and disulfoton on model organism Caenorhabditis elegans to evaluate their behavioural as well as developmental toxicity at different time intervals i.e., 4, 24, 48, and 72 hours (hrs) of exposure. A significant difference was observed in all the behavioural endpoints like locomotion, egg-laying, offspring count, and learning along with developmental parameters like mortality, paralysis, and growth rendering from moderate to high toxic effects. Based on the above screening, trichlorfon resulted in glutamatergic and cholinergic neurodegeneration along with elevated autofluorescence. Loss in Yellow fluorescent Protein (YFP) and Green Fluorescent Protein (GFP) was recorded by 57.96% and 30.52% using transgenic strains OH11124 (otIs388 [eat-4(fosmid)::SL2::YFP::H2B + (pBX)pha-1(+)] III) and OH13083 (otIs576 [unc-17(fosmid)::GFP + lin-44::YFP]). These results have shown the biological potency of toxicants in C. elegans and pave the way forward to provide insight into various neurogenerative diseases in humans.


2017 ◽  
Author(s):  
Peishan Yi ◽  
Chao Xie ◽  
Guangshuo Ou

AbstractKinesin-2 motors power the anterograde intraflagellar transport (IFT), a highly ordered process that assembles and maintains cilia. It remains elusive how kinesin-2 motors are regulated in vivo. Here we perform forward genetic screen to isolate suppressors that rescue the ciliary defects in the constitutive active mutation of OSM-3-kinesin (G444E) in C. elegans sensory neurons. We identify the C. elegans DYF-5 and DYF-18, which encode the homologs of mammalian male germ cell-associated kinase (MAK) and cell cycle-related kinase (CCRK). Using time-lapse fluorescence microscopy, we show that DYF-5 and DYF-18 are IFT cargo molecules and are enriched at the distal segments of sensory cilia. Mutations of dyf-5 and dyf-18 generate the elongated cilia and ectopic localization of kinesin-II at the ciliary distal segments. Genetic analyses reveal that dyf-5 and dyf-18 are also important for stabilizing the interaction between IFT particle and OSM-3-kinesin. Our data suggest that DYF-5 and DYF-18 act in the same pathway to promote handover between kinesin-II and OSM-3 in sensory cilia.


2002 ◽  
Vol 361 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Yusuke KATO ◽  
Tomoyasu AIZAWA ◽  
Hirokazu HOSHINO ◽  
Keiichi KAWANO ◽  
Katsutoshi NITTA ◽  
...  

Two genes encoding the ASABF (Ascarissuumantibacterial factor)-type antimicrobial peptide, abf-1 and abf-2, were identified in Caenorhabditis elegans. Recombinant ABF-2 exhibited potent microbicidal activity against Gram-positive and Gram-negative bacteria, and yeasts. The tissue-specific distribution estimated by immunofluorescence staining and transgenic analysis of a gfp fusion gene (where GFP corresponds to green fluorescent protein) suggested that ABF-2 contributes to surface defence in the pharynx. abf-1 contains a single intron at a conserved position, suggesting that asabf and abf originated from a common ancestor. Both transcripts for abf-1 and abf-2 were detected as two distinct forms, i.e. spliced leader (SL)1-trans-spliced with a long 5′-untranslated region (UTR) and SL-less with a short 5′-UTR. A polycistronic precursor RNA encoding ABF-1 and ABF-2 was detected, suggesting that these genes form an operon. An ‘opportunistic operon’ model for regulation of abf genes, including the generation of short SL-less transcripts, is proposed. In conclusion, C. elegans should have an immune defence system due to the antimicrobial peptides. C. elegans can be a novel model for innate immunity. Furthermore, the combination of biochemical identification in Ascaris suum and homologue hunting in C. elegans should be a powerful method of finding rapidly evolved proteins, such as some immune-related molecules in C. elegans.


Genetics ◽  
2019 ◽  
Vol 213 (4) ◽  
pp. 1197-1207 ◽  
Author(s):  
Ivana Sfarcic ◽  
Theresa Bui ◽  
Erin C. Daniels ◽  
Emily R. Troemel

Genetic reporters such as the green fluorescent protein (GFP) can facilitate measurement of promoter activity and gene expression. However, animal autofluorescence limits the sensitivity of GFP and other fluorescent reporters in whole-animal settings like in the nematode Caenorhabditis elegans. Here, we present a highly sensitive Nanoluciferase (NanoLuc)-based method in a multiwell format to detect constitutive and inducible gene expression in C. elegans. We optimize detection of bioluminescent signals from NanoLuc in C. elegans and show that it can be detected at 400,000-fold over background in a population of 100 animals expressing intestinal NanoLuc driven by the vha-6 promoter. We can reliably detect signal in single vha-6p::Nanoluc-expressing worms from all developmental stages. Furthermore, we can detect signal from a 1/100 dilution of lysate from a single vha-6p::Nanoluc-expressing adult and from a single vha-6p::Nanoluc-expressing adult “hidden” in a pool of 5000 N2 wild-type animals. We also optimize various steps of this protocol, which involves a lysis step that can be performed in minutes. As a proof-of-concept, we used NanoLuc to monitor the promoter activity of the pals-5 stress/immune reporter and were able to measure 300- and 50-fold increased NanoLuc activity after proteasome blockade and infection with microsporidia, respectively. Altogether, these results indicate that NanoLuc provides a highly sensitive genetic reporter for rapidly monitoring whole-animal gene expression in C. elegans.


1999 ◽  
Vol 10 (12) ◽  
pp. 4311-4326 ◽  
Author(s):  
Barth Grant ◽  
David Hirsh

The Caenorhabditis elegans oocyte is a highly amenable system for forward and reverse genetic analysis of receptor-mediated endocytosis. We describe the use of transgenic strains expressing a vitellogenin::green fluorescent protein (YP170::GFP) fusion to monitor yolk endocytosis by theC. elegans oocyte in vivo. This YP170::GFP reporter was used to assay the functions of C. eleganspredicted proteins homologous to vertebrate endocytosis factors using RNA-mediated interference. We show that the basic components and pathways of endocytic trafficking are conserved between C. elegans and vertebrates, and that this system can be used to test the endocytic functions of any new gene. We also used the YP170::GFP assay to identify rme(receptor-mediated endocytosis) mutants. We describe a new member of the low-density lipoprotein receptor superfamily, RME-2, identified in our screens for endocytosis defective mutants. We show that RME-2 is the C. elegans yolk receptor.


2006 ◽  
Vol 17 (12) ◽  
pp. 5053-5062 ◽  
Author(s):  
Oliver E. Blacque ◽  
Chunmei Li ◽  
Peter N. Inglis ◽  
Muneer A. Esmail ◽  
Guangshuo Ou ◽  
...  

The assembly and maintenance of cilia require intraflagellar transport (IFT), a microtubule-dependent bidirectional motility of multisubunit protein complexes along ciliary axonemes. Defects in IFT and the functions of motile or sensory cilia are associated with numerous human ailments, including polycystic kidney disease and Bardet–Biedl syndrome. Here, we identify a novel Caenorhabditis elegans IFT gene, IFT-associated gene 1 (ifta-1), which encodes a WD repeat-containing protein with strong homology to a mammalian protein of unknown function. Both the C. elegans and human IFTA-1 proteins localize to the base of cilia, and in C. elegans, IFTA-1 can be observed to undergo IFT. IFTA-1 is required for the function and assembly of cilia, because a C. elegans ifta-1 mutant displays chemosensory abnormalities and shortened cilia with prominent ciliary accumulations of core IFT machinery components that are indicative of retrograde transport defects. Analyses of C. elegans IFTA-1 localization/motility along bbs mutant cilia, where anterograde IFT assemblies are destabilized, and in a che-11 IFT gene mutant, demonstrate that IFTA-1 is closely associated with the IFT particle A subcomplex, which is implicated in retrograde IFT. Together, our data indicate that IFTA-1 is a novel IFT protein that is required for retrograde transport along ciliary axonemes.


1996 ◽  
Vol 134 (2) ◽  
pp. 537-548 ◽  
Author(s):  
T A Starich ◽  
R Y Lee ◽  
C Panzarella ◽  
L Avery ◽  
J E Shaw

The Drosophila melanogaster genes Passover and l(1)ogre and the Caenorhabditis elegans gene unc-7 define a gene family whose function is not known. We have isolated and characterized the C. elegans gene eat-5, which is required for synchronized pharyngeal muscle contractions, and find that it is a new member of this family. Simultaneous electrical and video recordings reveal that in eat-5 mutants, action potentials of muscles in the anterior and posterior pharynx are unsynchronized. Injection of carboxyfluorescein into muscles of the posterior pharynx demonstrates that all pharyngeal muscles are dye-coupled in wild-type animals; in eat-5 mutants, however, muscles of the anterior pharynx are no longer dye-coupled to posterior pharyngeal muscles. We show that a gene fusion of eat-5 to the green fluorescent protein is expressed in pharyngeal muscles. unc-7 and eat-5 are two of at least sixteen members of this family in C. elegans as determined by database searches and PCR-based screens. The amino acid sequences of five of these members in C. elegans have been deduced from cDNA sequences. Polypeptides of the family are predicted to have four transmembrane domains with cytoplasmic amino and carboxyl termini. We have constructed fusions of one of these polypeptides with beta-galactosidase and with green fluorescent protein. The fusion proteins appear to be localized in a punctate pattern at or near plasma membranes. We speculate that this gene family is required for the formation of gap junctions.


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