esp-8 was mapped to a 400-kb region of chromosome II and rescued with a 13-kb fragment containing the F59A6.1 coding sequence and 3.8 kb of upstream promoter sequence. F59A6.1 encodes the C. elegans ortholog of the mammalian MAPKKK ASK1 that has recently been found to correspond to the nsy-1 locus (9). The esp-8/nsy-1(ag3) mutation is a C-to-T change that converts the codon for Gln1013 to a premature stop codon just after the kinase domain. Another putative null allele,nsy-1(ky397) (9, 10), also showed sensitivity to PA14 comparable to esp-8/nsy-1(ag3) (Fig. 3A). Genetic and biochemical data suggest that NSY-1 is a direct activator of SEK-1 in the signaling pathway mediating asymmetric neuronal cell fate in AWC sensory neurons (8).. Although the Nsy phenotype corresponds to nsy-1 andsek-1 function in the AWC neurons, nsy-1 andsek-1 are expressed in a number of tissues types, including the intestine (8, 9). Whereas the signal transduction pathways that are involved in the Nsy and Esp phenotypes ...
Forkhead box O ( FoxO) transcription factors FoxO1, FoxO3a, FoxO4 and FoxO6, the mammalian orthologs of Caenorhabditis elegans DAF-16, are emerging as an important family of proteins that modulate the expression of genes ...
This gene is located on the long arm of chromosome 4 in a region that is associated with susceptibility to celiac disease. The encoded protein is similar to a Chinese hamster protein that is associated with spermatocyte and adipocyte differentiation. The C-terminus of the protein is also similar to a Caenorhabditis elegans protein that plays a role in lipid storage. In mammals, this protein is thought to function in the regulation of epithelial growth and differentiation, and in tumor development ...
Several of the RNAi candidates (dve-1; lin-40; nhr-49; ceh-20; lin-11; and nhr-77) appeared to non-discriminately shorten lifespan in all strains tested, suggesting that the corresponding transcription factors are broadly required for survival. Interestingly, four RNAi clones (ZC123.3; nhr-119; ceh-37; and aha-1) affected wild-type and isp-1;ctb-1 mutant worms lifespan to the same extent but exerted only a moderate or no effect on daf-16 and age-1 mutant longevity ...
Positioning edgetic residues in CED-9 structures. (a) Positions of edgetic residues in the CED-9 sequence. The portion of CED-9 present in the crystal (PDB ID c
1. Baldwin, J.G., Nadler, S.A., and Wall, D.H. 1997. Nematodes: Pervading the Earth and Linking all Life. Pp. 176-191. In: Raven, P.H. (ed.). National Academy Press, Washington, D.C. 625 pp.. 2. Bargmann, C. I. 1998. Neurobiology of the Caenorhabditis elegans genome. Science 282:2028-2033.. 3. Bargmann, C. I. And Mori, I. 1997. Chemotaxis and Thermotaxis. Pp. 717-737. In: Riddle, D.L., Blumenthal, T., Meyer, B.J. and Priess, J.R. (eds). C. elegans II. Cold Spring Harbor Laboratory Press, Plainview, NY 1222 pp.. 4. Bird, D.M. and Opperman, C. H. 1998. Caenorhabditis elegans. J. Nematol. 30:299-308.. 5. Bird, D.M., Opperman, C.H., Jones S.J.M., and Baillie, D.L. 1999. The Caenorhabditis elegans gemome: a guide in the post genomics age. Annu. Rev. Phytopathol. 37:247-265.. 6. Blaxter, M. 1998. Caenorhabditis elegans is a nematode. Science 282:2041-2046.. 7. Blaxter, M. and Bird, D. 1997. Parasitic nematodes. Pp. 851-878. In: Riddle, D.L., Blumenthal, T., Meyer, B.J. and Priess, J.R. (eds). C. ...
The molecular mechanisms underlying muscle atrophy during spaceflight are not well understood. We have analyzed the effects of a 10-day spaceflight on Caenorhabditis elegans muscle development. DNA microarray, real-time quantitative PCR, and quantitative western blot analyses revealed that the amount of MHC in both body-wall and pharyngeal muscle decrease in response to spaceflight. Decreased transcription of the body-wall myogenic transcription factor HLH-1 (CeMyoD) and of the three pharyngeal myogenic transcription factors, PEB-1, CEH-22 and PHA-4 were also observed. Upon return to Earth animals displayed reduced rates of movement, indicating a functional defect. These results demonstrate that C. elegans muscle development is altered in response to spaceflight. This altered development occurs at the level of gene transcription and was observed in the presence of innervation, not simply in isolated cells. This important finding coupled with past observations of decreased levels of the same ...
TY - JOUR. T1 - The human GRB2 and Drosophila Drk genes can functionally replace the Caenorhabditis elegans cell signaling gene sem-5. AU - Stern, M. J.. AU - Marengere, L. E.M.. AU - Daly, R. J.. AU - Lowenstein, E. J.. AU - Kokel, M.. AU - Batzer, A.. AU - Olivier, P.. AU - Pawson, T.. AU - Schlessinger, J.. PY - 1993/1/1. Y1 - 1993/1/1. N2 - Mutations in the Caenorhabditis elegans gene sem-5 affect cell signaling processes involved in guiding a class of cell migrations and inducing vulval cell fates. The sem-5 sequence encodes a protein comprised almost exclusively of SH2 and SH3 domains (SH, src homology region) that are found together in many signaling proteins and nonreceptor tyrosine kinases. A human protein, GRB2, was identified by its ability to associate with the activated human epidermal growth factor receptor (hEGFR). The GRB2 and Sem-5 proteins share an identical architecture of their SH2 and SH3 domains and 58% amino acid sequence identity. Here we demonstrate that GRB2 and a ...
The germ cells of multicellular organisms protect their developmental potential through specialized mechanisms. A shared feature of germ cells from worms to humans is the presence of nonmembrane-bound, ribonucleoprotein organelles called germ granules. Depletion of germ granules in Caenorhabditis elegans (i.e., P granules) leads to sterility and, in some germlines, expression of the neuronal transgene unc-119::gfp and the muscle myosin MYO-3. Thus, P granules are hypothesized to maintain germ cell totipotency by preventing somatic development, although the mechanism by which P granules carry out this function is unknown. In this study, we performed transcriptome and single molecule RNA-FISH analyses of dissected P granule-depleted gonads at different developmental stages. Our results demonstrate that P granules are necessary for adult germ cells to downregulate spermatogenesis RNAs and to prevent the accumulation of numerous soma-specific RNAs. P granule-depleted gonads that express the ...
We describe a general strategy for the genetic mapping in parallel of multiple restriction fragment length polymorphism (RFLP) loci. This approach allows the systematic identification for cloning of physical genetic loci within about 100 kb of any gene in Caenorhabditis elegans. We have used this strategy of parallel RFLP mapping to clone the heterochronic gene lin-14, which controls the timing and sequence of many C. elegans postembryonic developmental events. We found that of about 400 polymorphic loci in the C. elegans genome associated with the Tc1 family of repetitive elements, six are within 0.3 map unit of lin-14. The three closest lin-14-linked Tc1-containing restriction fragments were cloned and used to identify by hybridization an 830-kb region of contiguous cloned DNA fragments assembled from cosmid and yeast artificial chromosome libraries. A lin-14 intragenic recombinant that separated a previously cryptic lin-14 semidominant mutation from a cis-acting lin-14 suppressor mutation was ...
rdf:RDF xmlns:dcterms=http://purl.org/dc/terms/ xmlns:dc=http://purl.org/dc/elements/1.1/ xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns# xmlns:bibo=http://purl.org/ontology/bibo/ xmlns:dspace=http://digital-repositories.org/ontologies/dspace/0.1.0# xmlns:foaf=http://xmlns.com/foaf/0.1/ xmlns:void=http://rdfs.org/ns/void# xmlns:xsd=http://www.w3.org/2001/XMLSchema# , ,rdf:Description rdf:about=https://kops.uni-konstanz.de/rdf/resource/123456789/34900, ,bibo:uri rdf:resource=https://kops.uni-konstanz.de/handle/123456789/34900/, ,dc:creator,Deehan, Kevin,/dc:creator, ,dc:creator,Wilson, Kristy J.,/dc:creator, ,dc:language,eng,/dc:language, ,dcterms:abstract xml:lang=eng,UNC-89 is a giant polypeptide located at the sarcomeric M-line of Caenorhabditis elegans muscle. The human homologue is obscurin. To understand how UNC-89 is localized and functions, we have been identifying its binding partners. Screening a yeast two-hybrid library revealed that UNC-89 interacts with ...
Centrioles are microtubule-based organelles crucial for cell division, sensing and motility. In Caenorhabditis elegans, the onset of centriole formation requires notably the proteins SAS-5 and SAS-6, which have functional equivalents across eukaryotic evolution. Whereas the molecular architecture of SAS-6 and its role in initiating centriole formation are well understood, the mechanisms by which SAS-5 and its relatives function is unclear. Here, we combine biophysical and structural analysis to uncover the architecture of SAS-5 and examine its functional implications in vivo. Our work reveals that two distinct self-associating domains are necessary to form higher-order oligomers of SAS-5: a trimeric coiled coil and a novel globular dimeric Implico domain. Disruption of either domain leads to centriole duplication failure in worm embryos, indicating that large SAS-5 assemblies are necessary for function in vivo. Rogala, Kacper B; Dynes, Nicola J; Hatzopoulos, Georgios N; Yan, Jun; Pong, Sheng Kai;
Centrioles are microtubule-based organelles crucial for cell division, sensing and motility. In Caenorhabditis elegans, the onset of centriole formation requires notably the proteins SAS-5 and SAS-6, which have functional equivalents across eukaryotic evolution. Whereas the molecular architecture of SAS-6 and its role in initiating centriole formation are well understood, the mechanisms by which SAS-5 and its relatives function is unclear. Here, we combine biophysical and structural analysis to uncover the architecture of SAS-5 and examine its functional implications in vivo. Our work reveals that two distinct self-associating domains are necessary to form higher-order oligomers of SAS-5: a trimeric coiled coil and a novel globular dimeric Implico domain. Disruption of either domain leads to centriole duplication failure in worm embryos, indicating that large SAS-5 assemblies are necessary for function in vivo.
The nematode worm Caenorhabditis elegans is a model system for the study of the genetic basis of aging. Maternal-effect mutations in four genes-clk-1, clk-2, clk-3, and gro-1- interact genetically to determine both the duration of development and life-span. Analysis of the phenotypes of these mutants suggests the existence of a general physiological clock in the worm. Mutations in certain genes involved in dauer formation (an alternative larval stage induced by adverse conditions in which development is arrested) can also extend life-span, but the life extension of Clock mutants appears to be independent of these genes. The daf-2(e1370) clk-1(e2519) worms, which carry life-span-extending mutations from two different pathways, live nearly five times as long as wild-type worms.. ...
The vaccinia-related kinases (VRKs) are highly conserved throughout the animal kingdom and phosphorylate several chromatin proteins and transcription factors. In early Caenorhabditis elegans embryos, VRK-1 is required for proper nuclear envelope formation. In this work, we present the first investigation of the developmental role of VRKs by means of a novel C. elegans vrk-1 mutant allele. We found that VRK-1 is essential in hermaphrodites for formation of the vulva, uterus, and utse and for development and maintenance of the somatic gonad and thus the germ line. VRK-1 regulates anchor cell polarity and the timing of anchor cell invasion through the basement membranes separating vulval and somatic gonadal cells during the L3 larval stage. VRK-1 is also required for proper specification and proliferation of uterine cells and sex myoblasts. Expression of the fibroblast growth factor-like protein EGL-17 and its receptor EGL-15 is reduced in vrk-1 mutants, suggesting that VRK-1 might act at least ...
Development of the nematode Caenorhabditis elegans is highly reproducible and the fate of every somatic cell has been reported. We describe here a previously uncharacterized cell fate in C. elegans: we show that germ cells, which in hermaphrodites can differentiate into sperm and oocytes, also undergo apoptotic cell death. In adult hermaphrodites, over 300 germ cells die, using the same apoptotic execution machinery (ced-3, ced-4 and ced-9) as the previously described 131 somatic cell deaths. However, this machinery is activated by a distinct pathway, as loss of egl-1 function, which inhibits somatic cell death, does not affect germ cell apoptosis. Germ cell death requires ras/MAPK pathway activation and is used to maintain germline homeostasis. We suggest that apoptosis eliminates excess germ cells that acted as nurse cells to provide cytoplasmic components to maturing oocytes.. ...
The gene lin-11 is required for the asymmetric division of a vulval precursor cell type in the nematode Caenorhabditis elegans. Putative lin-11 complementary DNAs were sequenced and found to encode a protein that contains both a homeodomain and two tandem copies of a novel cysteine-rich motif: C-X2- …
Mouse mAb M38 was used in indirect immunofluorescence experiments to detect a stage-specific antigen on the surface of the first larval stage (L1) of the free-living nematode Caenorhabditis elegans, and to detect alterations in the apparent expression of this antigen in two distinct classes of C. elegans mutants. In previously described srf-2 and srf-3 mutants (Politz S. M., M. T. Philipp, M. Estevez, P.J. OBrien, and K. J. Chin. 1990. Proc. Natl. Acad. Sci. USA. 87:2901-2905), the antigen is not detected on the surface of any stage. Conversely, in srf-(yj43) and other similar mutants, the antigen is expressed on the surface of the first through the fourth (L4) larval stages. To understand the molecular basis of these alterations, the antigen was characterized in gel immunoblotting experiments. After SDS-PAGE separation and transfer to nitrocellulose, M38 detected a protein antigen in extracts of wild-type L1 populations. The antigen was sensitive to digestion by Pronase and O-glycanase ...
During the course of normal embryonic and post-embryonic development, 131 cells in a Caenorhabditis elegans hermaphrodite undergo programmed cell death. Loss of function mutations in either of the genes ced-3 or ced-4 abolish cell deaths, enabling these undead cells to survive and be incorporated into the adult with no obvious deleterious consequences. Ultrastructural reconstructions have shown that undead cells exhibit many differentiated characteristics. Most of the reconstructed cells appeared to be neurons with all the characteristic features associated with such cells, such as processes, synaptic vesicles and presynaptic specializations. However, clear morphological differences were seen among the undead neurons, suggesting a diversity of cell type. One of the reconstructed cells was a rectal epithelial cell, which had displaced its lineal sister that normally functions in this role. Removal of the ability to undergo programmed cell death by mutation therefore reveals a diversity of ...
Members of the Hox gene family encode transcription factors that specify positional identity along the anterior-posterior axis of nearly all metazoans. One among the Caenorhabditis elegans Hox genes is egl-5. A deletion allele of egl-5 was isolated in a screen for animals which fail to develop swollen tails when exposed to the bacterial pathogen Microbacterium nematophilum. We show that compromised rectal development, which occurs as a result of loss of egl-5 function, results in a failure of rectal epithelial cells to express the ERK MAP kinase mpk-1, which was previously shown to mediate tail-swelling in response to bacterial infection. Tissue-specific rescue experiments demonstrated that egl-5 and mpk-1 act autonomously in rectal cells in the morphological response. The weak egl-5 allele (n1439), which does not compromise rectal development, fails to affect tail-swelling. We find that this allele carries an inserted repeat element approximately 13.8 kb upstream of the egl-5 open reading frame, which
Aging is characterized by general physiological decline over time. A hallmark of human senescence is the onset of various age-related afflictions including neurodegeneration, cardiovascular disease and cancer. Although environmental and stochastic factors undoubtedly contribute to the increased incidence of disease with age, recent studies suggest that intrinsic genetic determinants govern both life span and overall health. Current aging research aims at achieving the longevity dividend, in which life span extension in humans is accomplished with a concomitant increase in the quality of life (Olshansky et al., 2007). Significant progress has been made using model organisms, especially the nematode worm Caenorhabditis elegans, to delineate the genetic and biochemical pathways involved in aging to identify strategies for therapeutic intervention in humans. In this review, we discuss how C. elegans has contributed to our understanding of insulin signaling and aging. ...
Defining a behavior that requires the function of specific neurons in the free-living nematode Caenorhabditis elegans can allow one to screen for mutations that disrupt the specification or function of those neurons. We identified serotonin-immunoreactive neurons required for tail curling or turnin …
Extensive studies have been carried out on Caenorhabditis elegans as a model organism to elucidate mechanisms of aging and the effects of perturbing known aging-related genes on lifespan and behavior. This research has generated large amounts of experimental data that is increasingly difficult to integrate and analyze with existing databases and domain knowledge. To address this challenge, we demonstrate a scalable and effective approach for automatic evidence gathering and evaluation that leverages existing experimental data and literature-curated facts to identify genes involved in aging and lifespan regulation in C. elegans. We developed a semantic knowledge base for aging by integrating data about C. elegans genes from WormBase with data about 2005 human and model organism genes from GenAge and 149 genes from GenDR, and with the Bio2RDF network of linked data for the life sciences. Using HyQue (a Semantic Web tool for hypothesis-based querying and evaluation) to interrogate this knowledge base, we
RNA interference (RNAi) is a widespread and widely exploited phenomenon which has potential as a strategy for both the treatment of disease and pest control. RNAi results in down‐regulation of a specific gene in response to the production of small interfering RNAs (siRNAs). RNAi is one of a family of processes mediated by small non‐coding RNAs [1], [2]. In Caenorhabditis elegans, and in a number of other organisms, RNAi is systemic so that the introduction of dsRNA into one tissue triggers gene silencing in other tissues [3], [4], [5], [6], [7]. Furthermore, systemic RNAi enables C. elegans and other organisms to exhibit environmental RNAi [5]. For example, feeding C. elegans on bacteria expressing dsRNA initiates a widespread RNAi response [8], [9]. Studies in C. elegans and other organisms have provided mechanistic insights into RNAi [4], [10], [11], [12], [13], although the role of exogenous RNAi in the normal life of C. elegans and other animals remains unclear [14].. Whilst C. elegans ...
Mutations in the gene unc-53 of Caenorhabditis elegans result in behavioral and anatomical abnormalities. Immunocytochemistry and electron microscopy revealed neuroanatomical defects in all main longitudinal nervous tracts. Whole tracts were found to
Caenorhabditis elegans MIG-13 protein: required for positioning of Q neuroblasts and their descendents along the anteroposterior axis; isolated from Caenorhabditis elegans; amino acid sequence in first source; GenBAnk AF150958
As a consequence of the Earths axial rotation, organisms display daily recurring rhythms in behavior and biochemical properties, such as hormone titers. The neuronal system controlling such changes is best studied in the fruit fly Drosophila melanogaster. In the nematode worm Caenorhabditis elegans, most homologs of these genes function in the heterochronic pathway controlling the (timing of) developmental events. Recent data indicate that in the worm at least one of the genes involved in developmental timing is also active in circadian rhythm control, thereby opening up new perspectives on a central (neuronal) timer interfering with many processes. Also, new neuropeptidergic clock homologs have been identified in nematodes, supporting the idea of a broad range of clock-regulated targets. We will describe the current knowledge on homologous clock genes in C. elegans with a focus on the recently discovered pigment dispersing factor gene homologs. Similarities between developmental and daily ...
The C. elegans heterochronic gene pathway consists of a cascade of regulatory genes that are temporally controlled to specify the timing of developmental events. Mutations in heterochronic genes cause temporal transformations in cell fates in which stage-specific events are omitted or reiterated. Here we show that let-7 is a heterochronic switch gene. Loss of let-7 gene activity causes reiteration of larval cell fates during the adult stage, whereas increased let-7 gene dosage causes precocious expression of adult fates during larval stages. let-7 encodes a temporally regulated 21-nucleotide RNA that is complementary to elements in the 3 untranslated regions of the heterochronic genes lin-14, lin-28, lin-41, lin-42 and daf-12, indicating that expression of these genes may be directly controlled by let-7. A reporter gene bearing the lin-41 3 untranslated region is temporally regulated in a let-7-dependent manner. A second regulatory RNA, lin-4, negatively regulates lin-14 and lin-28 through RNA-RNA
Genetic studies have identified over a dozen genes that function in programmed cell death (apoptosis) in the nematode Caenorhabditis elegans(1-3). Although the ultimate effects on cell survival or engulfment of mutations in each cell death gene have been extensively described, much less is known about how these mutations affect the kinetics of death and engulfment, or the interactions between these two processes. We have used four-dimensional-Nomarski time-lapse video microscopy to follow in detail how cell death genes regulate the extent and kinetics of apoptotic cell death and removal in the early C. elegans embryo. Here we show that blocking engulfment enhances cell survival when cells are subjected to weak pro-apoptotic signals. Thus, genes that mediate corpse removal can also function to actively kill cells.. ...
Abstract The insulin/insulin-like growth factor-like signaling (IIS) pathway in metazoans has evolutionarily conserved roles in growth control, metabolic homeostasis, stress responses, reproduction, and lifespan. Genetic manipulations that reduce IIS in the nematode worm Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the mouse have been shown not only to produce substantial increases in lifespan but also to ameliorate several age-related diseases. In C. elegans, the multitude of phenotypes produced by the reduction in IIS are all suppressed in the absence of the worm FOXO transcription factor, DAF-16, suggesting that they are all under common regulation. It is not yet clear in other animal models whether the activity of FOXOs mediate all of the physiological effects of reduced IIS, especially increased lifespan. We have addressed this issue by examining the effects of reduced IIS in the absence of dFOXO in Drosophila, using a newly generated null allele of dfoxo. We found ...
A specific behavioural response of Caenorhabditis elegans, the rapid increase of locomotion in response to anoxia/reoxygenation called the O2-ON response, has been used to model key aspects of ischaemia/reperfusion injury. A genetic suppressor screen demonstrated a direct causal role of CYP (cytochrome P450)-13A12 in this response and suggested that CYP-eicosanoids, which in mammals influence the contractility of cardiomyocytes and vascular smooth muscle cells, might function in C. elegans as specific regulators of the body muscle cell activity. In the present study we show that co-expression of CYP-13A12 with the NADPH-CYP-reductase EMB-8 in insect cells resulted in the reconstitution of an active microsomal mono-oxygenase system that metabolized EPA (eicosapentaenoic acid) and also AA (arachidonic acid) to specific sets of regioisomeric epoxy and hydroxy derivatives. The main products included 17,18-EEQ (17,18-epoxyeicosatetraenoic acid) from EPA and 14,15-EET (14,15-epoxyeicosatrienoic acid) ...
Phagocytosis of dying cells is critical in development and immunity1-3. Although proteins for recognition and engulfment of cellular debris following cell death are known4,5, proteins that directly mediate phagosome sealing are uncharacterized. Furthermore, whether all phagocytic targets are cleared using the same machinery is unclear. Degeneration of morphologically complex cells, such as neurons, glia and melanocytes, produces phagocytic targets of various shapes and sizes located in different microenvironments6,7. Thus, such cells offer unique settings to explore engulfment programme mechanisms and specificity. Here, we report that dismantling and clearance of a morphologically complex Caenorhabditis elegans epithelial cell requires separate cell soma, proximal and distal process programmes. Similar compartment-specific events govern the elimination of a C. elegans neuron. Although canonical engulfment proteins drive cell soma clearance, these are not required for process removal. We find that EFF-1,
Benzimidazole anti-microtubule drugs, such as benomyl, induce paralysis and slow the growth of the nematode Caenorhabditis elegans. We have identified 28 mutations in C. elegans that confer resistance to benzimidazoles. All resistant mutations map to a single locus, ben-1. Virtually all these mutations are genetically dominant. Molecular cloning and DNA sequence analysis established that ben-1 encodes a beta-tubulin. Some resistant mutants are completely deleted for the ben-1 gene. Since the deletion strains appear to be fully resistant to the drugs, the ben-1 product appears to be the only benzimidazole-sensitive beta-tubulin in C. elegans. Furthermore, since animals lacking ben-1 are viable and coordinated, the ben-1 beta-tubulin appears to be nonessential for growth and movement. The ben-1 function is likely to be redundant in the nematode genome. ...
Caenorhabditis elegans shares several molecular and physiological homologies with humans and thus plays a key role in studying biological processes. As a consequence, much progress has been made in automating the analysis of C. elegans. However, there is still a strong need to achieve more progress in automating the analysis of static images of adult worms. In this paper, a three-phase semi-automated system has been proposed. As a first phase, a novel segmentation framework, based on variational level sets and local pressure force function, has been introduced to handle effectively images corrupted with intensity inhomogeneity. Then, a set of robust invariant symbolic features for high-throughput screening of image-based C. elegans phenotypes are extracted. Finally, a classification model is applied to discriminate between the different subsets. The proposed system demonstrates its effectiveness in measuring morphological phenotypes in individual worms of C. elegans.. ...
Cytoskeletal regulation is important in cell migration. The Caenorhabditis elegans gonadal distal tip cells (DTCs) offer a simple model with which to investigate the mechanism of cell migration in organogenesis. Here, we report that one of the spectraplakin isoforms, VAB-10B1, plays an essential role in cell and nuclear migration of DTCs by regulating the actin and microtubule (MT) cytoskeleton. In the vab-10(tk27) mutant, which lacks VAB-10B1, alignment of filamentous (F)-actin and MTs was weakly and severely disorganized, respectively, which resulted in a failure to translocate the DTC nucleus and a premature termination of DTC migration. An MT growing-tip marker, EBP-2-GFP, revealed that polarized outgrowth of MTs towards the nuclei of migrating DTCs was strikingly impaired in tk27 animals. A vab-10 mini-gene encoding only the actin- and MT-binding domains significantly rescued the gonadal defects, suggesting that VAB-10B1 has a role in linking actin and MT filaments. These results suggest ...
Amino Acid Sequence, Animals, Apoptosis/*physiology, Apoptosis Regulatory Proteins, Caenorhabditis/genetics, Caenorhabditis elegans/embryology/genetics/*physiology, Caenorhabditis elegans Proteins/genetics/metabolism/*physiology, DNA/genetics/radiation effects, DNA Damage, Gene Deletion, Gene Expression Regulation; Developmental/radiation effects, Heat-Shock Proteins/genetics, Models; Biological, Molecular Sequence Data, Mutation, Proto-Oncogene Proteins/genetics/metabolism, Repressor Proteins/genetics, Sequence Homology; Amino Acid, Tumor Suppressor Protein p53/genetics/physiology, X-Rays ...
Purification of biomass ethanol from the products of brown sugar yeast-fermentation produces a large amount of residue. This fermentation residue contains abundant brown sugar-derived nutrients and is mainly used as compost or livestock feed. However, the in vivo physiological effects of oral residue ingestion are not known. The purpose of this study was to elucidate the physiological action and molecular mechanism of fermented brown sugar residue in nematode stress tolerance, aging, and lifespan using Caenorhabditis elegans. Fermented brown sugar residue was divided into two layers, supernatant and precipitate, and each was given to nematodes. Analysis of motility and survival rate under thermal stress revealed reduced mobility and increased survival rate following treatment with fermented brown sugar residue. The survival rate of nematodes under 1% H2O2 was markedly increased by the residue and mitochondrial membrane depolarization was induced and mitochondrial radical oxygen species levels increased.
Gene expression is regulated at multiple levels, including transcription and translation, as well as mRNA and protein stability. Although systems-level functions of transcription factors and microRNAs are rapidly being characterized, few studies have focused on the posttranscriptional gene regulation by RNA binding proteins (RBPs). RBPs are important to many aspects of gene regulation. Thus, it is essential to know which genes encode RBPs, which RBPs regulate which gene(s), and how RBP genes are themselves regulated. Here we provide a comprehensive compendium of RBPs from the nematode Caenorhabditis elegans (wRBP1.0). We predict that as many as 887 (4.4%) of C. elegans genes may encode RBPs ~250 of which likely function in a gene-specific manner. In addition, we find that RBPs, and most notably gene-specific RBPs, are themselves enriched for binding and modification by regulatory proteins, indicating the potential for extensive regulation of RBPs at many different levels. wRBP1.0 will provide a
The WAVE/SCAR complex promotes actin nucleation through the Arp2/3 complex, in response to Rac signaling. We show that loss of WVE-1/GEX-1, the only C. elegans WAVE/SCAR homolog, by genetic mutation or by RNAi, has the same phenotype as loss of GEX-2/Sra1/p140/PIR121, GEX-3/NAP1/HEM2/KETTE, or ABI-1/ABI, the three other components of the C. elegans WAVE/SCAR complex. We find that the entire WAVE/SCAR complex promotes actin-dependent events at different times and in different tissues during development. During C. elegans embryogenesis loss of CED-10/Rac1, WAVE/SCAR complex components, or Arp2/3 blocks epidermal cell migrations despite correct epidermal cell differentiation. 4D movies show that this failure occurs due to decreased membrane dynamics in specific epidermal cells. Unlike myoblasts in Drosophila, epidermal cell fusions in C. elegans can occur in the absence of WAVE/SCAR or Arp2/3. Instead we find that subcellular enrichment of F-actin in epithelial tissues requires the Rac-WAVE/SCAR-Arp2/3
Cell invasion is a tightly controlled process occurring during development and tumor progression. The nematode Caenorhabditis elegans serves as a genetic model to study cell invasion during normal development. In the third larval stage, the anchor ce
The dauer larva state and the age-1 mutation, both of which extend life-span in Caenorhabditis elegans, were tested for hyperresistance to cellular damage that may be relevant to aging. The age-1 strain TJ401 displayed hyperresistance to oxidative stress relative to its parental strain. The activities of two enzymes that protect cells from oxidative damage, superoxide dismutase (SOD) and catalase, showed an age-dependent increase in mutant animals, which was not seen in the parental strain. These increases in activities paralleled the time course of the hyperresistance. The results are consistent with the age-1 gene product functioning as a negative regulator of SOD and catalase activities. In wild-type and age-1 dauer larvae, elevated levels of SOD activity, but not of catalase activity, were present when compared with young adults. The common increase in SOD activity prompted cloning the C. elegans Cu/Zn SOD gene. Its position on the physical map of the genome was in the region to which the ...
A search of the C. elegans genome for potential homologues of the yeast MEN/SIN genes revealed several candidate genes, although for some of these genes the sequence similarities were only limited and for TEM1, CDC15, and BFA1 no putative homologues could be identified (Table I). All candidate genes were tested in C. elegans for a possible function in a hypothetical MEN/SIN-like regulatory network, using RNAi to deplete the corresponding products. For depletion of putative MEN/SIN gene products, both RNAi feeding and injection methods (Montgomery and Fire, 1998; Timmons et al., 2001) were tried to maximize the probability of functional inactivation. The results of these experiments are summarized in Table I. A priori, we had expected that depletion of a gene product required for the regulation of mitotic exit or the onset of cytokinesis should result in embryonic lethality. However, of all components tested, only the depletion of the C. elegans homologue of the budding yeast Cdc14p phosphatase ...
The pace of technical developments allowing the direct manipulation of genome sequences has seen a marked acceleration in recent years with the emergence of RNA-targeted nucleases derived from bacterial immune systems (Doudna and Charpentier 2014; Zetsche et al. 2015). In particular, the binary system relying on the Streptococcus pyogenes Cas9 endonuclease targeted by CRISPR (clustered, regularly interspaced, short, palindromic repeat) RNAs has been successfully used to generate point mutations, deletion, or DNA insertions in an ever-growing number of experimental systems. S. pyogenes CRISPR/Cas9 has been adapted early on in the model nematode Caenorhabditis elegans (Friedland et al. 2013; Dickinson et al. 2013; Chen et al. 2013; Frøkjær-Jensen 2013; Dickinson and Goldstein 2016). Previously, heritable genome engineering could only be achieved in C. elegans by remobilizing a Drosophila Mos1 transposon, which could be inserted and excised in the germline (Robert and Bessereau 2007; ...
Mutations in the human Mid1 gene cause Opitz G/BBB syndrome, which is characterized by various midline closure defects. The Caenorhabditis elegans homolog of Mid1, madd-2, positively regulates signaling by the unc-40 Netrin receptor during the extension of muscle arms to the midline and in axon guidance and branching. During uterine development, a specialized cell called anchor cell (AC) breaches the basal laminae separating the uterus from the epidermis and invades the underlying vulval tissue. AC invasion is guided by an UNC-6 Netrin signal from the ventral nerve cord and an unknown guidance signal from the vulval cells. Using genetic epistasis analysis, we show that madd-2 regulates AC invasion downstream of or in parallel with the Netrin signaling pathway. Measurements of AC shape, polarity and dynamics indicate that MADD-2 prevents the formation of ectopic AC protrusions in the absence of guidance signals. We propose that MADD-2 represses the intrinsic invasive capacity of the AC, while the ...
Brenner, S. (1974). The genetics of Caenorhabditis elegans. Genetics 77, 71-94.. Chitwood, B. G., and Chitwood, M. B. (1974). Introduction to Nematology. University Park Press, Baltimore.. Hodgkin, J. A. (1974). Genetic and Anatomical Aspects of the Caenorhabditis elegans Male, Ph.D. thesis. University of Cambridge, Cambridge, England.. Hodgkin, J. A., and Brenner, S. (1977). Mutations causing transformation of sexual phenotype in the nematode Caenorhabditis elegans. Genetics 86, 275-287.. Kimble, J., and Hirsh, D. (1979). The Postembryonic cell lineages of the hermaphrodite and male gonads in Caenorhabditis elegans. Develop. Biol. 70, 396-417.. Klass, M., Wolf, N., and Hirsh, D. (1976). Development of the male reproductive system and sexual transformation in the nematode Caenorhabditis elegans. Develop. Biol. 52, 1-18.. Seligman, I. M., Filshie, B. K., Doy, F. A., and Crossley, A. C. (1975). Hormonal control of mor-phogenetic cell death of the wing hypodermis in Lucilia cuprina. Tissue Cell ...
TY - JOUR. T1 - The Caenorhabditis elegans AMP-activated protein kinase AAK-2 is phosphorylated by LKB1 and is required for resistance to oxidative stress and for normal motility and foraging behavior. AU - Lee, Hyojin. AU - Jeong, Soo Cho. AU - Lambacher, Nils. AU - Lee, Jieun. AU - Lee, Se Jin. AU - Tae, Hoon Lee. AU - Gartner, Anton. AU - Koo, Hyeon Sook. PY - 2008/5/30. Y1 - 2008/5/30. N2 - AAK-2 is one of two α isoforms of the AMP-activated protein kinase in Caenorhabditis elegans and is involved in life span maintenance, stress responses, and germ cell cycle arrest upon dauer entry. We found that AAK-2 was phosphorylated at threonine 243 in response to paraquat treatment and that this phosphorylation depends on PAR-4, the C. elegans LKB1 homologue. Both aak-2 mutation and par-4 knockdown increased the sensitivity of C. elegans worms to paraquat, and the double deficiency did not further increase sensitivity, indicating that aak-2 and par-4 act in a linear pathway. Both mutations also ...
TY - JOUR. T1 - Origin, properties, and regulated expression of multiple mRNAs encoded by the protein kinase C1 gene of Caenorhabditis elegans. AU - Land, Marianne. AU - Islas-Trejo, Alma. AU - Rubin, Charles S.. N1 - Copyright: Copyright 2005 Elsevier B.V., All rights reserved.. PY - 1994/5/20. Y1 - 1994/5/20. N2 - Recently, we cloned and characterized cDNA encoding a novel, protein kinase C (designated PKC1B) from Caenorhabditis elegans. PKC1B (707 amino acid residues) is a developmentally regulated, calcium-independent kinase that is expressed exclusively in sensory neurons and related interneurons. We have now discovered a mechanism by which a second, distinct mRNA (PKC1A mRNA) with increased protein coding potential is generated from the C. elegans PKC1 gene. PKC1A mRNA is produced in a process that involves the utilization of an alternative, distal promoter, the incorporation of two unique exons into the mRNA, and alternative cis/trans splicing. Diversity among PKC1 gene transcripts is ...
Approximately 10% of Caenorhabditis elegans nervous system synapses are electrical, that is, gap junctions composed of innexins. The locomotory nervous system consists of several pairs of interneurons and three major classes of motor neurons, all with stereotypical patterns of connectivity that include gap junctions. Mutations in the two innexin genes unc-7 and unc-9 result in identical uncoordinated movement phenotypes, and their respective gene products were investigated for their contribution to electrical synapse connectivity. unc-7 encodes three innexin isoforms. Two of these, UNC-7S and UNC-7SR, are functionally equivalent and play an essential role in coordinated locomotion. UNC-7S and UNC-7SR are widely expressed and co-localize extensively with green fluorescent protein-tagged innexin UNC-9 in the ventral and dorsal nerve cords. A subset of UNC-7S/SR expression visualizes gap junctions formed between the AVB forward command interneurons and their B class motor neuron partners. Experiments
The role of lipids in the process of embryonic development of Caenorhabditis elegans is still poorly understood. Cytochrome P450s, a class of lipid-modifying enzymes, are good candidates to be involved in the production or degradation of lipids essential for development. We investigated two highly similar cytochrome P450s in C. elegans, cyp-31A2 and cyp-31A3, that are homologs of the gene responsible for Bietti crystalline corneoretinal dystrophy in humans. Depletion of both cytochromes either by RNAi or using a double deletion mutant, led to the failure of establishing the correct polarity of the embryo and to complete the extrusion of the polar bodies during meiosis. In addition, the egg became osmotic sensitive and permeable to dyes. The phenotype of cyp-31A2 or cyp-31A3 is very similar to a class of mutants that have polarization and osmotic defects (POD), thus the genes were renamed to pod-7 and pod-8, respectively. Electron microscopic analysis demonstrated that the activity of pod-7/pod-8 ...
The elt-1 RNAi phenotype provides a useful insight into the function of seam cells during postembryonic development. The loss of alae in the adult cuticle confirms the role of seam cells in producing this structure, which has previously been shown by laser ablation studies (Singh and Sulston, 1978). The apparently normal appearance of the underlying cuticle is also consistent with these previous studies and presumably this is derived from the dorsal/ventral hypodermis. RNAi of elt-1, applied during larval development, has a severe effect on the integrity of adult worms within a few hours of the L4-adult moult. Adult hermaphrodites show a `burst-vulva phenotype, in which the uterus herneates through the vulva. This is likely to be a direct consequence of seam-cell loss because the lateral seam anchors the vulval and uterine cells in position by virtue of the utse cell connection (Michaux et al., 2001; Newman et al., 2000; Sharma-Kishore et al., 1999). This hypothesis is supported by the ...
Caenorhabditis elegans are free-living bacterivorous nematodes that naturally consume bacteria as food source. As an excellent genetic model, C. elegans has proven to be a successful system to study innate immune responses to human pathogens, which resulted in identification of many evolutionarily conserved defense pathways. Most of these studies examined innate immune pathway mutants in a single genetic background in response to monoculture of human pathogens that worms might not necessarily encounter in the wild. While this has led to the successful genetic dissection of these defense pathways, in order to fully understand their biological functions, the relevant ecological and evolutionary context needs to be taken into account. The bacterial environment C. elegans naturally encounter is likely to be highly heterogeneous. While many bacteria are mainly considered as dietary resource for worms, some could be potential pathogens. Worms thus constantly face the challenge to defend against the ...
Aims: To investigate the role of endogenous hydrogen sulfide (H2S) in the control of aging and healthspan of Caenorhabditis elegans. Results: We show that the model organism, C. elegans, synthesizes H2S. Three H2S-synthesizing enzymes are present in C. elegans, namely cystathionine γ lyase (CSE), cystathionine β synthetase, and 3-mercaptopyruvate transferase (MPST or 3-MST). Genetic deficiency of mpst-1 (3-MST orthologue 1), but not cth-2 (CSE orthologue), reduced the lifespan of C. elegans. This effect was reversed by a pharmacological H2S donor (GYY4137). GYY4137 also reduced detrimental age-dependent changes in a range of physiological indices, including pharyngeal contraction and defecation. Treatment of C. elegans with GYY4137 increased the expression of several age-related, stress response, and antioxidant genes, whereas MitoSOX Red fluorescence, indicative of reactive oxygen species generation, was increased in mpst-1 knockouts and decreased by GYY4137 treatment. GYY4137 additionally ...
TY - JOUR. T1 - Mechanism of transport of IFT particles in C. elegans cilia by the concerted action of kinesin-II and OSM-3 motors. AU - Pan, Xiaoyu. AU - Ou, Guangshuo. AU - Civelekoglu-Scholey, Gul. AU - Blacque, Oliver E.. AU - Endres, Nicholas F.. AU - Tao, Li. AU - Mogilner, Alex. AU - Leroux, Michel R.. AU - Vale, Ronald D.. AU - Scholey, Jonathan M.. PY - 2006/9/25. Y1 - 2006/9/25. N2 - The assembly and function of cilia on Caenorhabditis elegans neurons depends on the action of two kinesin-2 motors, heterotrimeric kinesin-II and homodimeric OSM-3-kinesin, which cooperate to move the same intraflagellar transport (IFT) particles along microtubule (MT) doublets. Using competitive in vitro MT gliding assays, we show that purified kinesin-II and OSM-3 cooperate to generate movement similar to that seen along the cilium in the absence of any additional regulatory factors. Quantitative modeling suggests that this could reflect an alternating action mechanism, in which the motors take turns to ...
The Caenorhabditis elegans Regulator of Presynaptic Morphology (RPM)-1 is a member of a conserved family of proteins called Pam/Highwire/RPM-1 (PHR) proteins. PHR proteins are key regulators of neuronal development. In C. elegans, RPM-1 (regulator of presynaptic morphology-1) regulates axon termination and guidance in the mechanosensory neurons, and regulates synapse formation in the mechanosensory and motor neurons (Po et al., 2010). In adult C. elegans, RPM-1 also plays a role in axon regeneration in motor neurons (Hammarlund et al., 2009). Importantly, Drosophila Highwire, zebrafish Esrom/Phr1, and murine Phr1 also regulate synapse formation and axon extension highlighting the evolutionarily conserved function of the PHR proteins (Po et al., 2010).. Previous studies showed that RPM-1 functions, in part, as an E3 ubiquitin ligase by binding to the F box SyNaptic protein (FSN)-1 and negatively regulating a MAPK pathway that includes: the Dual Leucine zipper-bearing Kinase (DLK)-1, MAPK Kinase ...
The C. elegans hermaphrodite vulva develops during postembryonic (larval) development from ventral epidermal precursors, and connects the developing uterus to the external environment. In the adult, the vulva is necessary for egg-laying (see Egg-laying) and for copulation with males (see Male mating behavior). Vulval development has attracted general interest for three main reasons. First, it serves as a paradigm for organogenesis. In particular, vulva development represents a well-understood case in which invariant development arises from multiple cell-cell interactions. It is also a striking example of tissue remodeling: the formation of a hole at a precise location in an organism. Second, it has been important for the genetic analyses of signaling and signal transduction by epidermal growth factor (EGF)-receptor LET-23 and RAS LET-60; (see RTKRas/MAP kinase signaling), LIN-12 (see LIN-12/Notch signaling in C. elegans), and WNT (see Wnt signaling), as well as the functions of the SynMuv and ...
The C. elegans hermaphrodite vulva develops during postembryonic (larval) development from ventral epidermal precursors, and connects the developing uterus to the external environment. In the adult, the vulva is necessary for egg-laying (see Egg-laying) and for copulation with males (see Male mating behavior). Vulval development has attracted general interest for three main reasons. First, it serves as a paradigm for organogenesis. In particular, vulva development represents a well-understood case in which invariant development arises from multiple cell-cell interactions. It is also a striking example of tissue remodeling: the formation of a hole at a precise location in an organism. Second, it has been important for the genetic analyses of signaling and signal transduction by epidermal growth factor (EGF)-receptor LET-23 and RAS LET-60; (see RTKRas/MAP kinase signaling), LIN-12 (see LIN-12/Notch signaling in C. elegans), and WNT (see Wnt signaling), as well as the functions of the SynMuv and ...
TY - JOUR. T1 - Regulation of Tcl transposable elements in Caenorhabditis elegans.. AU - Emmons, S. W.. AU - Ruan, K. S.. AU - Levitt, A.. AU - Yesner, L.. PY - 1985. Y1 - 1985. N2 - C. elegans strains contain variable numbers of a 1.6-kb transposable genetic element. Activity of this element, which is denoted Tcl, shows regulation at at least two levels. At one level, excision of Tcl elements occurs in somatic cells at a frequency several orders of magnitude higher than in germ cells. Evidence is presented suggesting that this results from regulation at the level of trans-acting functions that are required for excision or that repress excision. At the second level, germ line transposition of Tcl occurs at greater frequency in some strains than in others. The hypothesis is proposed that this is because Tcl is one component of a two-element system, the second element of which differs between strains. Evidence for a second putative transposable element family in C. elegans is presented. This ...
The nematode Caenorhabditis elegans has been much studied as a host for microbial infection. Some pathogens can infect its intestine, while others attack via its external surface. Cultures of Caenorhabditis isolated from natural environments have yielded new nematode pathogens, such as microsporidia and viruses. We report here a novel mechanism for bacterial attack on worms, discovered during investigation of a diseased and coinfected natural isolate of Caenorhabditis from Cape Verde. Two related coryneform pathogens (genus Leucobacter) were obtained from this isolate, which had complementary effects on C. elegans and related nematodes. One pathogen, Verde1, was able to cause swimming worms to stick together irreversibly by their tails, leading to the rapid formation of aggregated worm-stars. Adult worms trapped in these aggregates were immobilized and subsequently died, with concomitant growth of bacteria. Trapped larval worms were sometimes able to escape from worm-stars by undergoing autotomy,
Early Caenorhabditis elegans embryos provide an excellent model for the study of developmental processes. Development can be studied by direct observation under the light microscope and can be perturbed using laser manipulations, drug inhibitor treatments, and genetic mutants. The first division of the C. elegans embryo is asymmetric, generating two daughter cells unequal in size and developmental fate. These distinct fates are generated by the partitioning of cytoplasmic determinants during the first mitotic cell cycle. Partitioning of these determinants is thought to be driven by cytoplasmic flow. Recent studies in C. elegans in the past year have identified a number of components necessary for this flow, giving us a clearer picture of the molecular mechanisms underlying developmental asymmetry.
The eukaryotic ubiquitin-conjugation system sets the turnover rate of many proteins and includes activating enzymes (E1s), conjugating enzymes (UBCs/E2s), and ubiquitin-protein ligases (E3s), which are responsible for activation, covalent attachment and substrate recognition, respectively. There are also ubiquitin-like proteins with distinct functions, which require their own E1s and E2s for attachment. We describe the results of RNA interference (RNAi) experiments on the E1s, UBC/E2s and ubiquitin-like proteins in Caenorhabditis elegans. We also present a phylogenetic analysis of UBCs. The C. elegans genome encodes 20 UBCs and three ubiquitin E2 variant proteins. RNAi shows that only four UBCs are essential for embryogenesis: LET-70 (UBC-2), a functional homolog of yeast Ubc4/5p, UBC-9, an ortholog of yeast Ubc9p, which transfers the ubiquitin-like modifier SUMO, UBC-12, an ortholog of yeast Ubc12p, which transfers the ubiquitin-like modifier Rub1/Nedd8, and UBC-14, an ortholog of Drosophila Courtless.
Neuropeptides regulate all aspects of behavior in multicellular organisms. Because of their ability to act at long distances, neuropeptides can exert their effects beyond the conventional synaptic connections, thereby adding an intricate layer of complexity to the activity of neural networks. In the nematode Caenorhabditis elegans, a large number of neuropeptide genes that are expressed throughout the nervous system have been identified.The actions of these peptides supplement the synaptic connections of the 302 neurons, allowing for fine tuning of neural networks and increasing the ways in which behaviors can be regulated. In this review, we focus on a large family of genes encoding FMRFamide-related peptides (FaRPs). These genes, the flp genes, have been used as a starting point to identifying flp genes throughout Nematoda. Nematodes have the largest family of FaRPs described thus far. The challenges in the future are the elucidation of their functions and the identification of the receptors and
Metals are major contaminants that influence human health. Many metals have physiologic roles, but excessive levels can be harmful. Advances in technology have made toxicogenomic analyses possible to characterize the effects of metal exposure on the entire genome. Much of what is known about cellular responses to metals has come from mammalian systems; however the use of non-mammalian species is gaining wider attention. Caenorhabditis elegans (C. elegans) is a small round worm whose genome has been fully sequenced and its development from egg to adult is well characterized. It is an attractive model for high throughput screens due to its short lifespan, ease of genetic mutability, low cost and high homology with humans. Research performed in C. elegans has led to insights in apoptosis, gene expression and neurodegeneration, all of which can be altered by metal exposure. Additionally, by using worms one can potentially study how the mechanisms that underline differential responses to metals in nematodes
Under experimental conditions, virtually all behaviors of Caenorhabditis elegans are achieved by combinations of simple locomotion, including forward, reversal movement, turning by deep body bending, and gradual shallow turning. To study how worms regulate these locomotion in response to sensory information, acidic pH avoidance behavior was analyzed by using worm tracking system. In the acidic pH avoidance, we characterized two types of behavioral maneuvers that have similar behavioral sequences in chemotaxis and thermotaxis. A stereotypic reversal-turn-forward sequence of reversal avoidance caused an abrupt random reorientation, and a shallow gradual turn in curve avoidance caused non-random reorientation in a less acidic direction to avoid the acidic pH. Our results suggest that these two maneuvers were each triggered by a distinct threshold pH. A simulation study using the two-distinct-threshold model reproduced the avoidance behavior of the real worm, supporting the presence of the threshold.
An additional genetic locus in Caenorhabditis elegans, unc-116, was identified in a screen for mutations resulting in defective locomotion. unc-116 was cloned by use of a transposon insertion mutant and the physical and genetic map of the genome. The cDNA sequence predicts an 815-amino acid protein. Based upon sequence comparison and secondary structure predictions, unc-116 encodes all three domains of the kinesin heavy chain: the motor, stalk, and tail. While the motor and tail domains have a high degree of identity to the equivalent domains of cloned kinesin heavy chains, the rodII domain of the stalk is significantly shorter than those previously reported and is not predicted to form a coiled-coil alpha-helix. Analysis of mutational defects in two C. elegans genes encoding anterograde motor molecules, unc-116 and unc-104, should provide insight into the in vivo functions of these members of the kinesin heavy chain superfamily.. ...
Involved in several cell fate decisions that require cell-cell interactions. It is possible that lin-12 encodes a membrane-bound receptor for a signal that enables expression of the ventral uterine precursor cell fate. Activity in cell fate decisions and tumorigenesis is negatively regulated by sel-10.
The prototype of the Cdx family of homeodomain transcription factors is the Drosophila caudal protein. The initial maternal expression of caudal mRNA is ubiquitous and a posterior to anterior gradient of the protein develops during the syncytial blastoderm stage and persists until the onset of cellularization. Zygotic expression, which commences in the cellular blastoderm stage, is also localized to the posterior in a region which gives rise to terminal abdominal structures and the hindgut. During later embryonic development, expression of caudal is found in the midgut, hindgut and Malpigian tubules (MacDonald and Struhl, 1986; Mlodzik and Gehring, 1987).. Caudal homologues have been identified in a wide range of animal groups. A caudal‐related gene with a similar posterior expression pattern has been cloned from the short or intermediate germ band insect Bombyx mori and homologues are present in other invertebrates, including the nematode worm Caenorhabditis elegans and the annelid worm ...
Progressive neuronal deterioration accompanied by sensory functions decline is typically observed during aging. On the other hand, structural or functional alterations of specific sensory neurons extend lifespan in the nematode Caenorhabditis elegans. Hormesis is a phenomenon by which the body benefits from moderate stress of various kinds which at high doses are harmful. Several studies indicate that different stressors can hormetically extend lifespan in C. elegans and suggest that hormetic effects could be exploited as a strategy to slow down aging and the development of age-associated (neuronal) diseases in humans. Mitochondria play a central role in the aging process and hormetic-like bimodal dose-response effects on C. elegans lifespan have been observed following different levels of mitochondrial stress. Here we tested the hypothesis that mitochondrial stress may hormetically extend C. elegans lifespan through subtle neuronal alterations. In support of our hypothesis we find that life-lengthening
This paper presents a simple yet biologicallygrounded model for the neural control of Caenorhabditis elegans forward locomotion. We identify a minimal circuit within the C. elegans ventral cord that is likely to be sufficient to generate and sustain forward locomotion in vivo. This limited subcircuit appears to contain no obvious central pattern generated control. For that subcircuit, we present a model that relies on a chain of oscillators along the body which are driven by local and proximate mechano-sensory input. Computer simulations were used to study the model under a variety of conditions and to test whether it is behaviourally plausible. Within our model, we find that a minimal circuit of AVB interneurons and B-class motoneurons is sufficient to generate and sustain fictive forward locomotion patterns that are robust to significant environmental perturbations. The model predicts speed and amplitude modulation by the AVB command interneurons. An extended model including D-class ...
Strains. Nematodes were grown at 20°C under standard conditions that included uncrowded conditions and the presence of ample food (the Escherichia coli strain OP50). Wild-type nematodes were C. elegans strain N2. Mutant strains were obtained from the Caenorhabditis Genetic Center.. cDNA clones and expression constructs. Using degenerate oligonucleotide primers designed to amplify conserved regions of ionotropic glutamate receptors, we amplified DNA fragments from first-strand mixed-stage C. elegans cDNA that encoded portions of glr-3 and glr-5. These partial gene products were used to screen cDNA libraries at high stringency. After screening ∼106 clones, we obtained several partial cDNAs for each gene, indicating that mRNA encoding these glutamate receptor subunits is present at relatively low levels. Hence, we were unable to isolate full-length cDNAs using this approach. We also searched the published C. elegans genome for genes related in sequence to glr-1, glr-3, andglr-5 and identified ...
Multiphoton laser scanning microscopy (MPLSM) enables the production of long timelapse recordings from live fluorescent specimens. 1047- and 900-nm excitation were used to image both a vital fluorescent membrane probe, FM 4-64, and a modified green fluorescent protein (GFP) in live Caenorhabditis elegans embryos. Automated four-dimensional (4D) data collection yielded individual recordings comprising thousands of images, each allowing analysis of all of the cell divisions, contacts, migrations, and fusions that occur during a span of several hours of embryogenesis.. ©1998 Optical Society of America. Full Article , PDF Article ...
MicroRNAs (miRNAs) are small, approximately 22 nucleotide RNAs that regulate gene expression post-transcriptionally by base-pairing to complementary sites in the target mRNA. The first miRNA, lin-4, was discovered in 1993 in Caenorhabditis elegans; since then hundreds of miRNAs have been identified in C. elegans, Drosophila melanogaster, plants, mouse, and humans, where they approach a number equivalent to 1-2% of the protein-coding genes. With the exception of plants, miRNAs most commonly regulate targets by imperfectly pairing to 3 untranslated regions (UTRs), leading to translational repression or mRNA destabilization. The microRNA miR-196 is encoded at three paralogous locations in the HoxA, B, and C clusters in mammals and has conserved complementarity to the 3UTRs of Hoxb8, Hoxc8, and Hoxa7; in particular, miR-1 96 has complete complementarity to Hoxb8 with the exception of a single G:U wobble. In 2004, Yekta et al., were able to detect RNA fragments diagnostic of miR-1 96-directed ...
0, Molecular and genetic characterization of GON-2, a TRPM cation channel required for gonadogenesis in Caenorhabditis elegans A Thesis Submitted to the Faculty in partial fulfillment of the requirements for the degree of o Doctor of Philosophy in Biological Sciences by Rachel West DARTMOUTH COLLEGE Hanover, New Hampshire January, 2004 Examining9ommittee: Eric }. IAInbig (Chair) c:, Victor R. A)fibros Eleanor M. Maine Carol L. Folt Dean of Graduate Studies ...
TY - JOUR. T1 - Caenorhabditis elegans as an environmental monitor using DNA microarray analysis. AU - Custodia, N.. AU - Won, S. J.. AU - Novillo, A.. AU - Wieland, M.. AU - Li, C.. AU - Callard, I. P.. N1 - Copyright: Copyright 2020 Elsevier B.V., All rights reserved.. PY - 2001. Y1 - 2001. N2 - In order to assist in the identification of possible endocrine disrupting chemicals (EDC) in groundwater, we are developing Caenorhabolitis elegans as a high throughput bioassay system in which responses to EDC may be detected by gene expression using DNA microarray analysis. As a first step we examined gene expression patterns and vitellogenin responses of this organism to vertebrate steroids, in liquid culture. Western blotting showed the expected number and size of vitellogenin translation products after estrogen exposure. At 10-9 M, vitellogenin decreased, but at 10-7 and 10-5, vitellogenin was increased. Testosterone (10-5 M) increased the synthesis of vitellogenin, but progesterone-treated ...
PubMed journal article: Caenorhabditis elegans EAK-3 inhibits dauer arrest via nonautonomous regulation of nuclear DAF-16/FoxO activity. Download Prime PubMed App to iPhone, iPad, or Android
Current Name: Aphyosemion elegans. Describer(s), Year: (Boulenger, 1899). IDENTITY: elegans A.. Family-group Names: Nothobranchiidae Garman, 1895 , Nothobranchiinae Garman, 1895 , Nothobranchiini Garman, 1895 , Aphyosemina Huber, 2000 (#Aphyosemiina #Aphyosemionina) Genus: Aphyosemion Myers, 1924. Subgenus: Aphyosemion Myers, 1924. Abbreviated genus: A.. Abbreviated subgenus: (A.). Species: elegans. Index name: elegans: Aphyosemion elegans. Full name: Aphyosemion (Aphyosemion) elegans. TYPOLOGY: elegans A.. Original name: Haplochilus elegans. Describer(s): Boulenger. Year of description: 1899. Original description: Boulenger, G.A. 1899. Poissons nouveaux du Congo. Cinquième Partie. Cyprins, Silures, Cyprinodontes, Acanthopterygiens. Ann. Mus. Congo Belge, Tervuren, Zool. Ser., 1 (5): 113, pl. 47 (fig. 2).. Gender/Accordance: [Subst.]. SYSTEMATICS: elegans A.. Current status: valid sp.. Status evaluation (current): discussed {no red bars on male sides are mentioned in the description, only -red- ...