scholarly journals The Caenorhabditis elegans Replication Licensing Factor CDT-1 Is Targeted for Degradation by the CUL-4/DDB-1 Complex

2006 ◽  
Vol 27 (4) ◽  
pp. 1394-1406 ◽  
Author(s):  
Youngjo Kim ◽  
Edward T. Kipreos
Keyword(s):  
Caenorhabditis Elegans ◽  
Ubiquitin Ligase ◽  
S Phase ◽  
Null Mutant ◽  
Wild Type ◽  
C Elegans ◽  
Licensing Factor ◽  
Ubiquitin Ligase E3 ◽  
Blast Cells ◽  
Temporal Restriction

ABSTRACT The replication of genomic DNA is strictly regulated to occur only once per cell cycle. This regulation centers on the temporal restriction of replication licensing factor activity. Two distinct ubiquitin ligase (E3) complexes, CUL4/DDB1 and SCFSkp2, have been reported to target the replication licensing factor Cdt1 for ubiquitin-mediated proteolysis. However, it is unclear to what extent these two distinct Cdt1 degradation pathways are conserved. Here, we show that Caenorhabditis elegans DDB-1 is required for the degradation of CDT-1 during S phase. DDB-1 interacts specifically with CUL-4 but not with other C. elegans cullins. A ddb-1 null mutant exhibits extensive DNA rereplication in postembryonic BLAST cells, similar to what is observed in cul-4(RNAi) larvae. DDB-1 physically associates with CDT-1, suggesting that CDT-1 is a direct substrate of the CUL-4/DDB-1 E3 complex. In contrast, a deletion mutant of the C. elegans Skp2 ortholog, skpt-1, appears overtly wild type with the exception of an impenetrant gonad migration defect. There is no appreciable role for SKPT-1 in the degradation of CDT-1 during S phase, even in a sensitized ddb-1 mutant background. We propose that the CUL-4/DDB-1 ubiquitin ligase is the principal E3 for regulating the extent of DNA replication in C. elegans.

scholarly journals Caenorhabditis elegans triple null mutant lacking UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I

2004 ◽  
Vol 382 (3) ◽  
pp. 995-1001 ◽  
Author(s):  
Shaoxian ZHU ◽  
Andrew HANNEMAN ◽  
Vernon N. REINHOLD ◽  
Andrew M. SPENCE ◽  
Harry SCHACHTER
Keyword(s):  
Caenorhabditis Elegans ◽  
Chromosome Number ◽  
Null Mutant ◽  
Wild Type ◽  
Knock Out ◽  
C Elegans ◽  
In The Wild ◽  
Wild Type Worm ◽  
Type C ◽  
Nematode Worm

We have previously reported, from the nematode worm Caenor-habditis elegans, three genes (gly-12, gly-13 and gly-14) encoding enzymically active UDP-N-acetyl-D-glucosamine:α-3-D-mannoside β1,2-N-acetylglucosaminyltransferase I (GnT I), an enzyme essential for hybrid, paucimannose and complex N-glycan synthesis. We now describe a worm with null mutations in all three GnT I genes, gly-14 (III);gly-12 gly-13 (X) (III and X refer to the chromosome number). The triple-knock-out (TKO) worms have a normal phenotype, although they do not express GnT I activity and do not synthesize 31 paucimannose, complex and fucosylated oligomannose N-glycans present in the wild-type worm. The TKO worm has increased amounts of non-fucosylated oligomannose N-glycan structures, a finding consistent with the site of GnT I action. Five fucosylated oligomannose N-glycan structures were observed in TKO, but not wild-type, worms, indicating the presence of unusual GnT I-independent fucosyltransferases. It is concluded that wild-type C. elegans makes a large number of GnT I-dependent N-glycans that are not essential for normal worm development under laboratory conditions. The TKO worm may be more susceptible to mutations in other genes, thereby providing an approach for the identification of genes that interact with GnT I.

Developing a rapid throughput screen for detection of nematicidal activity of plant cysteine proteinases: the role of Caenorhabditis elegans cystatins

Parasitology ◽  
2013 ◽  
Vol 141 (2) ◽  
pp. 164-180 ◽  
Author(s):  
A. M. PHIRI ◽  
D. DE POMERAI ◽  
D. J. BUTTLE ◽  
J. M. B. BEHNKE
Keyword(s):  
Caenorhabditis Elegans ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Gastrointestinal Parasites ◽  
Apparent Difference ◽  
Cysteine Proteinases ◽  
Null Mutant ◽  
Wild Type ◽  
Free Living ◽  
C Elegans

SUMMARYPlant cysteine proteinases (CPs) from papaya (Carica papaya) are capable of killing parasitic nematode worms in vitro and have been shown to possess anthelmintic effects in vivo. The acute damage reported in gastrointestinal parasites has not been found in free-living nematodes such as Caenorhabditis elegans nor among the free-living stages of parasitic nematodes. This apparent difference in susceptibility might be the result of active production of cysteine proteinase inhibitors (such as cystatins) by the free-living stages or species. To test this possibility, a supernatant extract of refined papaya latex (PLS) with known active enzyme content was used. The effect on wild-type (Bristol N2) and cystatin null mutant (cpi-1−/− and cpi-2−/−) C. elegans was concentration-, temperature- and time-dependent. Cysteine proteinases digested the worm cuticle leading to release of internal structures and consequent death. Both cystatin null mutant strains were highly susceptible to PLS attack irrespective of the temperature and concentration of exposure, whereas wild-type N2 worms were generally resistant but far more susceptible to attack at low temperatures. PLS was able to induce elevated cpi-1 and cpi-2 cystatin expression. We conclude that wild-type C. elegans deploy cystatins CPI-1 and CPI-2 to resist CP attack. The results suggest that the cpi-1 or cpi-2 null mutants (or a double mutant combination of the two) could provide a cheap and effective rapid throughput C. elegans-based assay for screening plant CP extracts for anthelmintic activity.

The Effect of Mianserin on Lifespan of Caenorhabditis elegans is Abolished by Glucose

2021 ◽  
Vol 13 ◽  
Author(s):  
Abdullah Almotayri ◽  
Jency Thomas ◽  
Mihiri Munasinghe ◽  
Markandeya Jois
Keyword(s):  
Caenorhabditis Elegans ◽  
Scaffolding Protein ◽  
Lifespan Extension ◽  
Wild Type ◽  
E Coli ◽  
C Elegans ◽  
Risk Of Death ◽  
Increased Risk ◽  
Antidepressant Use ◽  
Extension Effect

Background: The antidepressant mianserin has been shown to extend the lifespan of Caenorhabditis elegans (C. elegans), a well-established model organism used in aging research. The extension of lifespan in C. elegans was shown to be dependent on increased expression of the scaffolding protein (ANK3/unc-44). In contrast, antidepressant use in humans is associated with an increased risk of death. The C. elegans in the laboratory are fed Escherichia coli (E. coli), a diet high in protein and low in carbohydrate, whereas a typical human diet is high in carbohydrates. We hypothesized that dietary carbohydrates might mitigate the lifespan-extension effect of mianserin. Objective: To investigate the effect of glucose added to the diet of C. elegans on the lifespan-extension effect of mianserin. Methods: Wild-type Bristol N2 and ANK3/unc-44 inactivating mutants were cultured on agar plates containing nematode growth medium and fed E. coli. Treatment groups included (C) control, (M50) 50 μM mianserin, (G) 73 mM glucose, and (M50G) 50 μM mianserin and 73 mM glucose. Lifespan was determined by monitoring the worms until they died. Statistical analysis was performed using the Kaplan-Meier version of the log-rank test. Results: Mianserin treatment resulted in a 12% increase in lifespan (P<0.05) of wild-type Bristol N2 worms but reduced lifespan by 6% in ANK3/unc-44 mutants, consistent with previous research. The addition of glucose to the diet reduced the lifespan of both strains of worms and abolished the lifespan-extension by mianserin. Conclusion: The addition of glucose to the diet of C. elegans abolishes the lifespan-extension effects of mianserin.

scholarly journals Sperm Competition in the Absence of Fertilization in Caenorhabditis elegans

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Andrew Singson ◽  
Katherine L Hill ◽  
Steven W L’Hernault
Keyword(s):  
Caenorhabditis Elegans ◽  
Sperm Competition ◽  
Sperm Function ◽  
Sperm Precedence ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Normal Sperm ◽  
Self Fertilization ◽  
Competition Assays

Abstract Hermaphrodite self-fertilization is the primary mode of reproduction in the nematode Caenorhabditis elegans. However, when a hermaphrodite is crossed with a male, nearly all of the oocytes are fertilized by male-derived sperm. This sperm precedence during reproduction is due to the competitive superiority of male-derived sperm and results in a functional suppression of hermaphrodite self-fertility. In this study, mutant males that inseminate fertilization-defective sperm were used to reveal that sperm competition within a hermaphrodite does not require successful fertilization. However, sperm competition does require normal sperm motility. Additionally, sperm competition is not an absolute process because oocytes not fertilized by male-derived sperm can sometimes be fertilized by hermaphrodite-derived sperm. These results indicate that outcrossed progeny result from a wild-type cross because male-derived sperm are competitively superior and hermaphrodite-derived sperm become unavailable to oocytes. The sperm competition assays described in this study will be useful in further classifying the large number of currently identified mutations that alter sperm function and development in C. elegans.

Streblus asper Lour. exerts MAPK and SKN-1 mediated anti-aging, anti-photoaging activities and imparts neuroprotection by ameliorating Aβ in Caenorhabditis elegans

2021 ◽  
pp. 1-17
Author(s):  
Mani Iyer Prasanth ◽  
James Michael Brimson ◽  
Dicson Sheeja Malar ◽  
Anchalee Prasansuklab ◽  
Tewin Tencomnao
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Stress Resistance ◽  
Vital Role ◽  
Transgenic Strain ◽  
Wild Type ◽  
Neuroprotective Effects ◽  
C Elegans ◽  
Streblus Asper

BACKGROUND: Streblus asper Lour., has been reported to have anti-aging and neuroprotective efficacies in vitro. OBJECTIVE: To analyze the anti-aging, anti-photoaging and neuroprotective efficacies of S. asper in Caenorhabditis elegans. METHODS: C. elegans (wild type and gene specific mutants) were treated with S. asper extract and analyzed for lifespan and other health benefits through physiological assays, fluorescence microscopy, qPCR and Western blot. RESULTS: The plant extract was found to increase the lifespan, reduce the accumulation of lipofuscin and modulate the expression of candidate genes. It could extend the lifespan of both daf-16 and daf-2 mutants whereas the pmk-1 mutant showed no effect. The activation of skn-1 was observed in skn-1::GFP transgenic strain and in qPCR expression. Further, the extract can extend the lifespan of UV-A exposed nematodes along with reducing ROS levels. Additionally, the extract also extends lifespan and reduces paralysis in Aβ transgenic strain, apart from reducing Aβ expression. CONCLUSIONS: S. asper was able to extend the lifespan and healthspan of C. elegans which was independent of DAF-16 pathway but dependent on SKN-1 and MAPK which could play a vital role in eliciting the anti-aging, anti-photoaging and neuroprotective effects, as the extract could impart oxidative stress resistance and neuroprotection.

scholarly journals Genetic, Behavioral and Environmental Determinants of Male Longevity in Caenorhabditis elegans

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1597-1610 ◽  
Author(s):  
David Gems ◽  
Donald L Riddle
Keyword(s):  
Caenorhabditis Elegans ◽  
Life Span ◽  
Wild Type ◽  
Neuronal Function ◽  
Nematode Caenorhabditis Elegans ◽  
Wild Isolate ◽  
Young Males ◽  
C Elegans ◽  
Single Sex ◽  
Solitary Males

Abstract Males of the nematode Caenorhabditis elegans are shorter lived than hermaphrodites when maintained in single-sex groups. We observed that groups of young males form clumps and that solitary males live longer, indicating that male-male interactions reduce life span. By contrast, grouped or isolated hermaphrodites exhibited the same longevity. In one wild isolate of C. elegans, AB2, there was evidence of copulation between males. Nine uncoordinated (unc) mutations were used to block clumping behavior. These mutations had little effect on hermaphrodite life span in most cases, yet many increased male longevity even beyond that of solitary wild-type males. In one case, the neuronal function mutant unc-64(e246), hermaphrodite life span was also increased by up to 60%. The longevity of unc-4(e120), unc-13(e51), and unc-32(e189) males exceeded that of hermaphrodites by 70–120%. This difference appears to reflect a difference in sex-specific life span potential revealed in the absence of male behavior that is detrimental to survival. The greater longevity of males appears not to be affected by daf-2, but is influenced by daf-16. In the absence of male-male interactions, median (but not maximum) male life span was variable. This variability was reduced when dead bacteria were used as food. Maintenance on dead bacteria extended both male and hermaphrodite longevity.

scholarly journals Goα Regulates Volatile Anesthetic Action in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 643-655 ◽  
Author(s):  
Bruno van Swinderen ◽  
Laura B Metz ◽  
Laynie D Shebester ◽  
Jane E Mendel ◽  
Paul W Sternberg ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Novel Mutation ◽  
Volatile Anesthetic ◽  
Loss Of Function ◽  
Wild Type ◽  
Α Subunit ◽  
C Elegans ◽  
Missense Mutant ◽  
Anesthetic Action ◽  
Mutant Phenotypes

Abstract To identify genes controlling volatile anesthetic (VA) action, we have screened through existing Caenorhabditis elegans mutants and found that strains with a reduction in Go signaling are VA resistant. Loss-of-function mutants of the gene goa-1, which codes for the α-subunit of Go, have EC50s for the VA isoflurane of 1.7- to 2.4-fold that of wild type. Strains overexpressing egl-10, which codes for an RGS protein negatively regulating goa-1, are also isoflurane resistant. However, sensitivity to halothane, a structurally distinct VA, is differentially affected by Go pathway mutants. The RGS overexpressing strains, a goa-1 missense mutant found to carry a novel mutation near the GTP-binding domain, and eat-16(rf) mutants, which suppress goa-1(gf) mutations, are all halothane resistant; goa-1(null) mutants have wild-type sensitivities. Double mutant strains carrying mutations in both goa-1 and unc-64, which codes for a neuronal syntaxin previously found to regulate VA sensitivity, show that the syntaxin mutant phenotypes depend in part on goa-1 expression. Pharmacological assays using the cholinesterase inhibitor aldicarb suggest that VAs and GOA-1 similarly downregulate cholinergic neurotransmitter release in C. elegans. Thus, the mechanism of action of VAs in C. elegans is regulated by Goα, and presynaptic Goα-effectors are candidate VA molecular targets.

Identification Of A Novel Gene Altered In The RQ1 Mutant Strain Affecting Motor Axon Migration In Caenorhabditis Elegans

2021 ◽  
Author(s):  
Haider Z. Naqvi
Keyword(s):  
Caenorhabditis Elegans ◽  
Axon Guidance ◽  
Motor Neurons ◽  
Genetic Background ◽  
Germ Line ◽  
Strong Indication ◽  
Wild Type ◽  
C Elegans ◽  
Novel Gene ◽  
Mutation Region

Novel genetic enhancer screens were conducted targeting mutants involved in the guidance of axons of the DA and DB classes of motor neurons in C. elegans. These mutations are expected in genes that function in parallel to the unc-g/Netrin pathway. The screen was conducted in an unc-5(e53) genetic background and enhancers of the axon guidance defects caused by the absence of UNC-5 were identified. Three mutants were previously identified in the screen called rq1, rq2 and rq3 and two additional mutants called H2-4 and M1-3, were isolated in this study. In order to identify the gene affected by the rq1 mutation, wild-type copies of genes in the mapped rq1 mutation region were injected into the mutants to rescue the phenotypic defects. This is a strong indication that the gene of interest is a novel gene called H04D03.1. Promising results indicate that the H04D03.1 protein also works in germ-line apoptosis.

scholarly journals Isolation, characterization and epistasis of fluoride-resistant mutants of Caenorhabditis elegans.

Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 145-154
Author(s):  
I Katsura ◽  
K Kondo ◽  
T Amano ◽  
T Ishihara ◽  
M Kawakami
Keyword(s):  
Caenorhabditis Elegans ◽  
Brood Size ◽  
Normal Growth ◽  
Fluoride Ion ◽  
Wild Type ◽  
Signal Transduction System ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Class 1 ◽  
Resistant Mutants

Abstract We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.

scholarly journals Temporal Transcriptomics of Gut Escherichia coli in Caenorhabditis elegans Models of Aging

2021 ◽  
Author(s):  
Joshua D. Brycki ◽  
Jeremy R. Chen See ◽  
Gillian R. Letson ◽  
Cade S. Emlet ◽  
Lavinia V. Unverdorben ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Caenorhabditis Elegans ◽  
Life Span ◽  
Wild Type ◽  
Health Span ◽  
Content Type ◽  
C Elegans ◽  
Evolutionarily Conserved

Previous research has reported effects of the microbiome on health span and life span of Caenorhabditis elegans , including interactions with evolutionarily conserved pathways in humans. We build on this literature by reporting the gene expression of Escherichia coli OP50 in wild-type (N2) and three long-lived mutants of C. elegans .

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