Regulation of the UNC-5 netrin receptor initiates the first reorientation of migrating distal tip cells in Caenorhabditis elegans

Development ◽  
2000 ◽  
Vol 127 (3) ◽  
pp. 585-594 ◽  
Author(s):  
M. Su ◽  
D.C. Merz ◽  
M.T. Killeen ◽  
Y. Zhou ◽  
H. Zheng ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Developmental Stage ◽  
Phase 1 ◽  
Critical Role ◽  
The Body ◽  
Dependent Manner ◽  
C Elegans ◽  
Guidance Cue ◽  
Distal Tip Cells ◽  
Tip Cells

Cell migrations play a critical role in animal development and organogenesis. Here, we describe a mechanism by which the migration behaviour of a particular cell type is regulated temporally and coordinated with over-all development of the organism. The hermaphrodite distal tip cells (DTCs) of Caenorhabditis elegans migrate along the body wall in three sequential phases distinguished by the orientation of their movements, which alternate between the anteroposterior and dorsoventral axes. The ventral-to-dorsal second migration phase requires the UNC-6 netrin guidance cue and its receptors UNC-5 and UNC-40, as well as additional, UNC-6-independent guidance systems. We provide evidence that the transcriptional upregulation of unc-5 in the DTCs is coincident with the initiation of the second migration phase, and that premature UNC-5 expression in these cells induces precocious turning in an UNC-6-dependent manner. The DAF-12 steroid hormone receptor, which regulates developmental stage transitions in C. elegans, is required for initiating the first DTC turn and for coincident unc-5 upregulation. We also present evidence for the existence of a mechanism that opposes or inhibits UNC-5 function during the longitudinal first migration phase and for a mechanism that facilitates UNC-5 function during turning. The facilitating mechanism presumably does not involve transcriptional regulation of unc-5 but may represent an inhibition of the phase 1 mechanism that opposes or inhibits UNC-5. These results, therefore, reveal the existence of two mechanisms that regulate the UNC-5 receptor that are critical for responsiveness to the UNC-6 netrin guidance cue and for linking the directional guidance of migrating distal tip cells to developmental stage advancements.

scholarly journals UHPLC-IM-Q-ToFMS analysis of maradolipids, found exclusively in Caenorhabditis elegans dauer larvae

2021 ◽  
Vol 413 (8) ◽  
pp. 2091-2102
Author(s):  
Michael Witting ◽  
Ulrike Schmidt ◽  
Hans-Joachim Knölker
Keyword(s):  
Caenorhabditis Elegans ◽  
Developmental Stage ◽  
Ion Mobility ◽  
Environmental Conditions ◽  
Multidimensional Data ◽  
Specific Class ◽  
Lipid Profiling ◽  
C Elegans ◽  
Tandem Mass Spectrometric ◽  
Dauer Larvae

AbstractLipid identification is one of the current bottlenecks in lipidomics and lipid profiling, especially for novel lipid classes, and requires multidimensional data for correct annotation. We used the combination of chromatographic and ion mobility separation together with data-independent acquisition (DIA) of tandem mass spectrometric data for the analysis of lipids in the biomedical model organism Caenorhabditis elegans. C. elegans reacts to harsh environmental conditions by interrupting its normal life cycle and entering an alternative developmental stage called dauer stage. Dauer larvae show distinct changes in metabolism and morphology to survive unfavorable environmental conditions and are able to survive for a long time without feeding. Only at this developmental stage, dauer larvae produce a specific class of glycolipids called maradolipids. We performed an analysis of maradolipids using ultrahigh performance liquid chromatography-ion mobility spectrometry-quadrupole-time of flight-mass spectrometry (UHPLC-IM-Q-ToFMS) using drift tube ion mobility to showcase how the integration of retention times, collisional cross sections, and DIA fragmentation data can be used for lipid identification. The obtained results show that combination of UHPLC and IM separation together with DIA represents a valuable tool for initial lipid identification. Using this analytical tool, a total of 45 marado- and lysomaradolipids have been putatively identified and 10 confirmed by authentic standards directly from C. elegans dauer larvae lipid extracts without the further need for further purification of glycolipids. Furthermore, we putatively identified two isomers of a lysomaradolipid not known so far. Graphical abstract

A Cuticle Collagen Encoded by the lon-3 Gene May Be a Target of TGF-β Signaling in Determining Caenorhabditis elegans Body Shape

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1631-1639
Author(s):  
Yo Suzuki ◽  
Gail A Morris ◽  
Min Han ◽  
William B Wood
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Shape ◽  
Small Body ◽  
Dependent Manner ◽  
Loss Of Function ◽  
Cellular Mechanisms ◽  
C Elegans ◽  
Gene Expression Analyses ◽  
Dose Dependent

Abstract The signaling pathway initiated by the TGF-β family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function (lf) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-β signaling controls C. elegans body shape by regulating cuticle composition.

scholarly journals Mutations Affecting Nerve Attachment of Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1611-1622 ◽  
Author(s):  
Go Shioi ◽  
Michinari Shoji ◽  
Masashi Nakamura ◽  
Takeshi Ishihara ◽  
Isao Katsura ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Body Wall ◽  
The Body ◽  
Genetic Loci ◽  
Muscle Attachment ◽  
C Elegans ◽  
Ventral Cord ◽  
Excretory Canal

Abstract Using a pan-neuronal GFP marker, a morphological screen was performed to detect Caenorhabditis elegans larval lethal mutants with severely disorganized major nerve cords. We recovered and characterized 21 mutants that displayed displacement or detachment of the ventral nerve cord from the body wall (Ven: ventral cord abnormal). Six mutations defined three novel genetic loci: ven-1, ven-2, and ven-3. Fifteen mutations proved to be alleles of previously identified muscle attachment/positioning genes, mup-4, mua-1, mua-5, and mua-6. All the mutants also displayed muscle attachment/positioning defects characteristic of mua/mup mutants. The pan-neuronal GFP marker also revealed that mutants of other mua/mup loci, such as mup-1, mup-2, and mua-2, exhibited the Ven defect. The hypodermis, the excretory canal, and the gonad were morphologically abnormal in some of the mutants. The pleiotropic nature of the defects indicates that ven and mua/mup genes are required generally for the maintenance of attachment of tissues to the body wall in C. elegans.

scholarly journals Screening for Presenilin Inhibitors Using the Free-Living Nematode, Caenorhabditis elegans

2004 ◽  
Vol 9 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Brenda R. Ellerbrock ◽  
Eileen M. Coscarelli ◽  
Mark E. Gurney ◽  
Timothy G. Geary
Keyword(s):  
Caenorhabditis Elegans ◽  
High Throughput Screening ◽  
Screening Method ◽  
Genetic System ◽  
Body Cavity ◽  
Egg Laying ◽  
The Body ◽  
Loss Of Function ◽  
C Elegans ◽  
Automated Method

Caenorhabditis elegans contains 3 homologs of presenilin genes that are associated with Alzheimer s disease. Loss-of-function mutations in C. elegans genes cause a defect in egg laying. In humans, loss of presenilin-1 (PS1) function reduces amyloid-beta peptide processing from the amyloid protein precursor. Worms were screened for compounds that block egg laying, phenocopying presenilin loss of function. To accommodate even relatively high throughput screening, a semi-automated method to quantify egg laying was devised by measuring the chitinase released into the culture medium. Chitinase is released by hatching eggs, but little is shed into the medium from the body cavity of a hermaphrodite with an egg laying deficient ( egl) phenotype. Assay validation involved measuring chitinase release from wild-type C. elegans (N2 strain), sel-12 presenilin loss-of-function mutants, and 2 strains of C. elegans with mutations in the egl-36K+ channel gene. Failure to find specific presenilin inhibitors in this collection likely reflects the small number of compounds tested, rather than a flaw in screening strategy. Absent defined biochemical pathways for presenilin, this screening method, which takes advantage of the genetic system available in C. elegans and its historical use for anthelminthic screening, permits an entry into mechanism-based discovery of drugs for Alzheimer s disease. ( Journal of Biomolecular Screening 2004:147-152)

Purification and physical properties of nematode mini-titins and their relation to twitchin

1991 ◽  
Vol 98 (4) ◽  
pp. 491-496
Author(s):  
R. Nave ◽  
D. Furst ◽  
U. Vinkemeier ◽  
K. Weber
Keyword(s):  
Caenorhabditis Elegans ◽  
Immunofluorescence Microscopy ◽  
Apparent Molecular Weight ◽  
The Body ◽  
Wild Type ◽  
Normal Muscle ◽  
Insect Muscle ◽  
C Elegans ◽  
Type C ◽  
Beta Structure

We have isolated mini-titin from the nematodes Ascaris lumbricoides and Caenorhabditis elegans under native conditions using a modification in the procedure to prepare this protein from insect muscle. The proteins have an apparent molecular weight of 600,000 and appear in oriented specimens as flexible thin rods with a length around 240–250 nm. The circular dichroism spectrum of the Ascaris protein is dominated by beta-structure. The proteins react with antibodies to insect mini-titin and also with antibodies raised against peptides contained in the sequence predicted for twitchin, the product of the Caenorhabditis elegans unc-22 gene. Antibodies to insect mini-titin decorate the body musculature as well as the pharynx of wild-type C. elegans in immunofluorescence microscopy. In the twitchin mutant E66 only the pharynx is decorated. We conclude that the mini-titins of invertebrate muscles defined earlier by ultrastructural criteria are very likely to be twitchins, i.e. molecules necessary for normal muscle contraction. We discuss the molecular properties of the proteins in the light of the sequence established for twitchin.

scholarly journals In the Model Host Caenorhabditis elegans, Sphingosine-1-Phosphate-Mediated Signaling Increases Immunity toward Human Opportunistic Bacteria

2020 ◽  
Vol 21 (21) ◽  
pp. 7813
Author(s):  
Kiho Lee ◽  
Iliana Escobar ◽  
Yeeun Jang ◽  
Wooseong Kim ◽  
Frederick M. Ausubel ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Stress Responses ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Cellular Functions ◽  
Kinase Gene ◽  
Concentration Dependent Manner ◽  
C Elegans ◽  
Opportunistic Bacteria ◽  
Free Living Nematode

Sphingosine-1-phophate (S1P) is a sphingolipid-derived signaling molecule that controls diverse cellular functions including cell growth, homeostasis, and stress responses. In a variety of metazoans, cytosolic S1P is transported into the extracellular space where it activates S1P receptors in a concentration-dependent manner. In the free-living nematode Caenorhabditis elegans, the spin-2 gene, which encodes a S1P transporter, is activated during Gram-positive or Gram-negative bacterial infection of the intestine. However, the role during infection of spin-2 and three additional genes in the C. elegans genome encoding other putative S1P transporters has not been elucidated. Here, we report an evolutionally conserved function for S1P and a non-canonical role for S1P transporters in the C. elegans immune response to bacterial pathogens. We found that mutations in the sphingosine kinase gene (sphk-1) or in the S1P transporter genes spin-2 or spin-3 decreased nematode survival after infection with Pseudomonas aeruginosa or Enterococcus faecalis. In contrast to spin-2 and spin-3, mutating spin-1 leads to an increase in resistance to P. aeruginosa. Consistent with these results, when wild-type C. elegans were supplemented with extracellular S1P, we found an increase in their lifespan when challenged with P. aeruginosa and E. faecalis. In comparison, spin-2 and spin-3 mutations suppressed the ability of S1P to rescue the worms from pathogen-mediated killing, whereas the spin-1 mutation had no effect on the immune-enhancing activity of S1P. S1P demonstrated no antimicrobial activity toward P. aeruginosa and Escherichia coli and only minimal activity against E. faecalis MMH594 (40 µM). These data suggest that spin-2 and spin-3, on the one hand, and spin-1, on the other hand, transport S1P across cellular membranes in opposite directions. Finally, the immune modulatory effect of S1P was diminished in C. eleganssek-1 and pmk-1 mutants, suggesting that the immunomodulatory effects of S1P are mediated by the p38 MAPK signaling pathway.

scholarly journals Embryonic extracts derived from the nematode Caenorhabditis elegans remove uracil from DNA by the sequential action of uracil-DNA glycosylase and AP (apurinic/apyrimidinic) endonuclease

2002 ◽  
Vol 365 (2) ◽  
pp. 547-553 ◽  
Author(s):  
Andrea SHATILLA ◽  
Dindial RAMOTAR
Keyword(s):  
Caenorhabditis Elegans ◽  
Excision Repair ◽  
Specific Inhibitor ◽  
Dna Glycosylase ◽  
Dependent Manner ◽  
Nematode Caenorhabditis Elegans ◽  
Uracil Dna Glycosylase ◽  
Ap Endonuclease ◽  
C Elegans ◽  
Ap Site

DNA bases continuously undergo modifications in response to endogenous reactions such as oxidation, alkylation or deamination. The modified bases are primarily removed by DNA glycosylases, which cleave the N-glycosylic bond linking the base to the sugar, to generate an apurinic/apyrimidinic (AP) site, and this latter lesion is highly mutagenic. Previously, no study has demonstrated the processing of these lesions in the nematode Caenorhabditis elegans. Herein, we report the existence of uracil-DNA glycosylase and AP endonuclease activities in extracts derived from embryos of C. elegans. These enzyme activities were monitored using a defined 5′-end 32P-labelled 42-bp synthetic oligonucleotide substrate bearing a single uracil residue opposite guanine at position 21. The embryonic extract rapidly cleaved the substrate in a time-dependent manner to produce a 20-mer product. The extract did not excise adenine or thymine opposite guanine, although uracil opposite either adenine or thymine was processed. Addition of the highly specific inhibitor of uracil-DNA glycosylase produced by Bacillus subtilis to the extract prevented the formation of the 20-mer product, indicating that removal of uracil is catalysed by uracil-DNA glycosylase. The data suggest that the 20-mer product was generated by a sequential reaction, i.e., removal of the uracil base followed by 5′-cleavage of the AP site. Further analysis revealed that product formation was dependent upon the presence of Mg2+, suggesting that cleavage of the AP site, following uracil excision, is carried out by a Mg2+-dependent AP endonuclease. It would appear that these activities correspond to the first two steps of a putative base-excision-repair pathway in C. elegans.

scholarly journals Chondroitin acts in the guidance of gonadal distal tip cells in C. elegans

2006 ◽  
Vol 300 (2) ◽  
pp. 635-646 ◽  
Author(s):  
Norio Suzuki ◽  
Hidenao Toyoda ◽  
Mitsue Sano ◽  
Kiyoji Nishiwaki
Keyword(s):  
C Elegans ◽  
Distal Tip Cells ◽  
Tip Cells

scholarly journals The Caenorhabditis elegans homologue of the extracellular calcium binding protein SPARC/osteonectin affects nematode body morphology and mobility.

1993 ◽  
Vol 4 (9) ◽  
pp. 941-952 ◽  
Author(s):  
J E Schwarzbauer ◽  
C S Spencer
Keyword(s):  
Extracellular Matrix ◽  
Caenorhabditis Elegans ◽  
Calcium Binding ◽  
Fusion Gene ◽  
Muscle Cells ◽  
Gene Organization ◽  
The Body ◽  
Matrix Assembly ◽  
Developmentally Regulated ◽  
C Elegans

The extracellular matrix-associated protein, SPARC (osteonectin [Secreted Protein Acidic and Rich in Cysteine]), modulates cell adhesion and induces a change in cell morphology. SPARC expression in mammals is developmentally regulated and is highest at sites of extracellular matrix assembly and remodeling such as parietal endoderm and bone. We have isolated cDNA and genomic DNA clones encoding the Caenorhabditis elegans homologue of SPARC. The gene organization is highly conserved, and the proteins encoded by mouse, human, and nematode genes are about 38% identical. SPARC consists of four domains (I-IV) based on predicted secondary structure. Using bacterial fusion proteins containing nematode domain I or the domain IV EF-hand motif, we show that, like the mammalian proteins, both domains bind calcium. In transgenic nematodes expressing a SPARC-lacZ fusion gene, beta-galactosidase staining accumulated in a striated pattern in the more heavily stained muscle cells along the body. Comparison of the pattern of transgene expression to unc-54-lacZ animals demonstrated that SPARC is expressed by body wall and sex muscle cells. Appropriate levels of SPARC are essential for normal C. elegans development and muscle function. Transgenic nematodes overexpressing the wild-type SPARC gene were abnormal. Embryos were deformed, and adult hermaphrodites had vulval protrusions and an uncoordinated (Unc) phenotype with reduced mobility and paralysis.

C. elegans as a model system to study the function of the COG complex in animal development

2006 ◽  
Vol 387 (8) ◽  
pp. 1031-1035 ◽  
Author(s):  
Yukihiko Kubota ◽  
Kiyoji Nishiwaki
Keyword(s):  
Golgi Apparatus ◽  
Complex Function ◽  
Model System ◽  
Secreted Proteins ◽  
Animal Development ◽  
C Elegans ◽  
Cog Complex ◽  
Family Protein ◽  
Distal Tip Cells ◽  
Tip Cells

AbstractThe conserved oligomeric Golgi (COG) complex is an octameric protein complex associated with the Golgi apparatus and is required for proper sorting and glycosylation of Golgi resident enzymes and secreted proteins. Although COG complex function has been extensively studied at the cellular and subcellular levels, its role in animal development mostly remains unknown. Recently, mutations in the components of the COG complex were found to cause abnormal gonad morphogenesis inCaenorhabditis elegans. InC. elegans, the COG complex acts in the glycosylation of an ADAM (a disintegrin and metalloprotease) family protein, MIG-17, which directs migration of gonadal distal tip cells to lead gonad morphogenesis. This is the first link between the COG complex and the function of an ADAM protease that is directly involved in organ morphogenesis, demonstrating the potential ofC. elegansas a model system to study COG function in animal development.

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