Suppression of the ELO-2 FA Elongation Activity Results in Alterations of the Fatty Acid Composition and Multiple Physiological Defects, Including Abnormal Ultradian Rhythms, in Caenorhabditis elegans

Abstract While the general steps of fatty acid (FA) biosynthesis are well understood, the individual enzymes involved in the elongation of long chain saturated and polyunsaturated FA (PUFA) are largely unknown. Recent research indicates that these enzymes might be of considerable physiological importance for human health. We use Caenorhabditis elegans to study FA elongation activities and associated abnormal phenotypes. In this article we report that the predicted C. elegans F11E6.5/ELO-2 is a functional enzyme with the FA elongation activity. It is responsible for the elongation of palmitic acid and is involved in PUFA biosynthesis. RNAi-mediated suppression of ELO-2 causes an accumulation of palmitate and an associated decrease in the PUFA fraction in triacylglycerides and phospholipid classes. This imbalance in the FA composition results in multiple phenotypic defects such as slow growth, small body size, reproductive defects, and changes in rhythmic behavior. ELO-2 cooperates with the previously reported ELO-1 in 20-carbon PUFA production, and at least one of the enzymes must function to provide normal growth and development in C. elegans. The presented data indicate that suppression of a single enzyme of the FA elongation machinery is enough to affect various organs and systems in worms. This effect resembles syndromic disorders in humans.

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

Genetics ◽

10.1093/genetics/162.4.1631 ◽

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.

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

Genetics ◽

10.1093/genetics/136.1.145 ◽

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.

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Broad oxygen tolerance in the nematode Caenorhabditis elegans

Journal of Experimental Biology ◽

10.1242/jeb.203.16.2467 ◽

2000 ◽

Vol 203 (16) ◽

pp. 2467-2478 ◽

Cited By ~ 5

Author(s):

W.A. Van Voorhies ◽

S. Ward

Keyword(s):

Caenorhabditis Elegans ◽

Metabolic Rate ◽

Developmental Stages ◽

Small Body ◽

Metabolic Cost ◽

Soil Nematode ◽

Nematode Caenorhabditis Elegans ◽

Oxygen Levels ◽

C Elegans ◽

Short Period

This study examined the effects of oxygen tensions ranging from 0 to 90 kPa on the metabolic rate (rate of carbon dioxide production), movement and survivorship of the free-living soil nematode Caenorhabditis elegans. C. elegans requires oxygen to develop and survive. However, it can maintain a normal metabolic rate at oxygen levels of 3.6 kPa and has near-normal metabolic rates at oxygen levels as low as 2 kPa. The ability to withstand low ambient oxygen levels appears to be a consequence of the small body size of C. elegans, which allows diffusion to supply oxygen readily to the cells without requiring any specialized respiratory or metabolic adaptations. Thus, the small size of this organism pre-adapts C. elegans to living in soil environments that commonly become hypoxic. Movement in C. elegans appears to have a relatively minor metabolic cost. Several developmental stages of C. elegans were able to withstand up to 24 h of anoxia without major mortality. Longer periods of anoxia significantly increased mortality, particularly for eggs. Remarkably, long-term exposure to 100 % oxygen had no effect on the metabolic rate of C. elegans, and populations were able to survive for a least 50 generations in 100 % (90 kPa) oxygen. Such hyperoxic conditions are fatal to most organisms within a short period.

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New strains for tissue-specific RNAi studies in Caenorhabditis elegans

10.1101/283325 ◽

2018 ◽

Author(s):

Jason S. Watts ◽

Henry F. Harrison ◽

Shizue Omi ◽

Quentin Guenthers ◽

James Dalelio ◽

...

Keyword(s):

Fatty Acid ◽

Caenorhabditis Elegans ◽

Gene Function ◽

Target Genes ◽

Resistant Mutant ◽

Knockout Mutant ◽

Tissue Specific ◽

Double Stranded Rna ◽

C Elegans ◽

Insight Into

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

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CSC-1

The Journal of Cell Biology ◽

10.1083/jcb.200207117 ◽

2003 ◽

Vol 161 (2) ◽

pp. 229-236 ◽

Cited By ~ 67

Author(s):

Alper Romano ◽

Annika Guse ◽

Ivica Krascenicova ◽

Heinke Schnabel ◽

Ralf Schnabel ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Genetic Analysis ◽

Chromosome Segregation ◽

Kinase Activity ◽

Aurora B ◽

Aurora B Kinase ◽

C Elegans ◽

The Individual

The Aurora B kinase complex is a critical regulator of chromosome segregation and cytokinesis. In Caenorhabditis elegans, AIR-2 (Aurora B) function requires ICP-1 (Incenp) and BIR-1 (Survivin). In various systems, Aurora B binds to orthologues of these proteins. Through genetic analysis, we have identified a new subunit of the Aurora B kinase complex, CSC-1. C. elegans embryos depleted of CSC-1, AIR-2, ICP-1, or BIR-1 have identical phenotypes. CSC-1, BIR-1, and ICP-1 are interdependent for their localization, and all are required for AIR-2 localization. In vitro, CSC-1 binds directly to BIR-1. The CSC-1/BIR-1 complex, but not the individual subunits, associates with ICP-1. CSC-1 associates with ICP-1, BIR-1, and AIR-2 in vivo. ICP-1 dramatically stimulates AIR-2 kinase activity. This activity is not stimulated by CSC-1/BIR-1, suggesting that these two subunits function as targeting subunits for AIR-2 kinase.

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Sublethal Effects of Ionic and Nanogold on the Nematode Caenorhabditis elegans

Journal of Toxicology ◽

10.1155/2018/6218193 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 5

Author(s):

Suanne Bosch ◽

Tarryn Lee Botha ◽

Anine Jordaan ◽

Mark Maboeta ◽

Victor Wepener

Keyword(s):

Caenorhabditis Elegans ◽

Sublethal Effects ◽

Low Cost ◽

Small Body ◽

Consumer Products ◽

Ion Release ◽

High Exposure ◽

C Elegans ◽

Short Period

The nematode Caenorhabditis elegans is used as an ecotoxicological model species in both aqueous medium and solid substrates. It is easy and of low cost to maintain in the laboratory and it produces hundreds of offspring within a short period of time. It also has a small body size (1 mm), making it possible for in vivo assays to be conducted in 12-well plates. Engineered nanomaterials (ENMs) are a class of emerging pollutants. Nanogold (nAu) is used in many consumer products and in vivo drug delivery. These materials can be released into the aquatic environment during production or discarding of consumer products. As nAu is insoluble in water, the sediment would become the final depository for the materials. It has become increasingly important to use sediment dwelling organisms to screen for possible toxicity of these ENMs. In this study C. elegans was exposed to a range of concentrations of nAu and ionic gold in M9-media, acting as a substitute for pore water. After 96-hour growth, fertility and reproduction were determined. Internal structure damage and internalisation of particles in C. elegans were determined by using SEM and CytoViva® Darkfield Imaging. From these images the nanomaterials are distributed around the oocytes in the reproductive organs, as well as the pharynx. Results obtained indicate that nAu affects reproduction more than growth due to internal gonad damage, albeit at very high exposure concentrations, indicating no toxicity at environmentally relevant concentrations. Ionic Au is more toxic than nAu and effects fertility and reproduction due to ion release. These results give more information regarding the toxicity and in vivo uptake of nAu and form part of an environmental risk assessment of ENMs.

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Cafestol Increases Fat Oxidation and Energy Expenditure in Caenorhabditis Elegans via DAF-12-dependent Pathway (OR34-02-19)

Current Developments in Nutrition ◽

10.1093/cdn/nzz031.or34-02-19 ◽

2019 ◽

Vol 3 (Supplement_1) ◽

Author(s):

Renalison Farias-Pereira ◽

Yeonhwa Park

Keyword(s):

Fatty Acid ◽

Lipid Metabolism ◽

Caenorhabditis Elegans ◽

Energy Expenditure ◽

Hormone Receptors ◽

Cholesterol Homeostasis ◽

Scientific Development ◽

Gene Expressions ◽

Fat Accumulation ◽

C Elegans

Abstract Objectives Cafestol, a diterpene found in coffee beans, is reported to be an agonist of farnesoid X receptors (FXR), nuclear hormone receptors involved in cholesterol homeostasis. It is also known that FXR plays critical roles in other metabolic pathways, including lipid metabolism; however, little is known about cafestol's effects on lipid metabolism. The goal of the current study was to investigate the effects of cafestol on lipid metabolism using Caenorhabditis elegans as a model system. Methods C. elegans was treated for 2 days with cafestol or 0.2% dimethyl sulfoxide (vehicle control). Triglycerides, locomotor behavior (an indicator of energy expenditure) and lipid metabolism-related gene expressions were measured. Results Cafestol at 60 µM significantly reduced fat accumulation by 20% compared to the control. Cafestol increased locomotor activity by 38% compared to the control. The effects of cafestol on fat accumulation were dependent on daf-12 (a functional homolog of the human FXR) and further confirmed by the upregulation of a DAF-12-target gene, fard-1 (the homolog of the human fatty acid reductase 1). Cafestol's fat-lowering effects were also dependent on tub-1 (an ortholog of the human TUBBY), which is involved in the neurological regulation of energy expenditure. Cafestol upregulated the expression of ech-1.1, involved in fatty acid β-oxidation; however, no effects of cafestol were observed on lipogenesis, lipolysis or lipid uptake and transport. Conclusions In conclusion, cafestol regulates lipid metabolism in C. elegans by increasing fatty acid β-oxidation and energy expenditure dependent on daf-12/FXR. Funding Sources Brazilian National Counsel of Technological and Scientific Development (CNPq).

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Identification of a Caenorhabditis elegans Δ6-fatty-acid-desaturase by heterologous expression in Saccharomyces cerevisiae

Biochemical Journal ◽

10.1042/bj3300611 ◽

1998 ◽

Vol 330 (2) ◽

pp. 611-614 ◽

Cited By ~ 103

Author(s):

A. Johnathan NAPIER ◽

J. Sandra HEY ◽

J. Dominic LACEY ◽

R. Peter SHEWRY

Keyword(s):

Saccharomyces Cerevisiae ◽

Fatty Acid ◽

Caenorhabditis Elegans ◽

Expressed Sequence Tag ◽

Cytochrome B5 ◽

Fatty Acid Desaturase ◽

Higher Plant ◽

Yeast Saccharomyces Cerevisiae ◽

C Elegans ◽

Δ6 Desaturase

We identified a cDNA expressed sequence tag from an animal (the nematode worm Caenorhabditis elegans) that showed weak similarity to a higher-plant microsomal Δ6-desaturase. A full-length cDNA clone was isolated and expressed in the yeast Saccharomyces cerevisiae. This demonstrated that the protein encoded by the C. elegans cDNA was that of a fatty acid Δ6-desaturase, as determined by the accumulation of γ-linolenic acid. The C. elegans Δ6-desaturase contained an N-terminalcytochrome b5 domain, indicating that it had a similar structure to that of the higher-plant Δ6-desaturase. The C. elegans Δ6-desaturase mapped to cosmid W08D2, a region of chromosome III. This is the first example of a Δ6-desaturase isolated from an animal and also the first example of an animal desaturase containing a cytochrome b5 domain.

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New Strains for Tissue-Specific RNAi Studies in Caenorhabditis elegans

G3 Genes|Genome|Genetics ◽

10.1534/g3.120.401749 ◽

2020 ◽

Vol 10 (11) ◽

pp. 4167-4176 ◽

Cited By ~ 1

Author(s):

Jason S. Watts ◽

Henry F. Harrison ◽

Shizue Omi ◽

Quentin Guenthers ◽

James Dalelio ◽

...

Keyword(s):

Fatty Acid ◽

Caenorhabditis Elegans ◽

Gene Function ◽

Target Genes ◽

Resistant Mutant ◽

Knockout Mutant ◽

Tissue Specific ◽

C Elegans ◽

Link Type ◽

Insight Into

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

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Juniperonic Acid Biosynthesis is Essential in Caenorhabditis elegans Lacking Δ6 Desaturase (fat-3) and Generates New ω-3 Endocannabinoids

Cells ◽

10.3390/cells9092127 ◽

2020 ◽

Vol 9 (9) ◽

pp. 2127

Author(s):

Sujay Guha ◽

Serafina Calarco ◽

M. Salomé Gachet ◽

Jürg Gertsch

Keyword(s):

Fatty Acid ◽

Caenorhabditis Elegans ◽

Polyunsaturated Fatty Acid ◽

Loss Of Function ◽

Compensatory Mechanisms ◽

C Elegans ◽

Juniperonic Acid ◽

Endocannabinoid Receptor ◽

G Protein Coupled ◽

Δ6 Desaturase

In eukaryotes, the C20:4 polyunsaturated fatty acid arachidonic acid (AA) plays important roles as a phospholipid component, signaling molecule and precursor of the endocannabinoid-prostanoid axis. Accordingly, the absence of AA causes detrimental effects. Here, compensatory mechanisms involved in AA deficiency in Caenorhabditis elegans were investigated. We show that the ω-3 C20:4 polyunsaturated fatty acid juniperonic acid (JuA) is generated in the C. elegans fat-3(wa22) mutant, which lacks Δ6 desaturase activity and cannot generate AA and ω-3 AA. JuA partially rescued the loss of function of AA in growth and development. Additionally, we observed that supplementation of AA and ω-3 AA modulates lifespan of fat-3(wa22) mutants. We described a feasible biosynthetic pathway that leads to the generation of JuA from α-linoleic acid (ALA) via elongases ELO-1/2 and Δ5 desaturase which is rate-limiting. Employing liquid chromatography mass spectrometry (LC-MS/MS), we identified endocannabinoid-like ethanolamine and glycerol derivatives of JuA and ω-3 AA. Like classical endocannabinoids, these lipids exhibited binding interactions with NPR-32, a G protein coupled receptor (GPCR) shown to act as endocannabinoid receptor in C. elegans. Our study suggests that the eicosatetraenoic acids AA, ω-3 AA and JuA share similar biological functions. This biosynthetic plasticity of eicosatetraenoic acids observed in C. elegans uncovers a possible biological role of JuA and associated ω-3 endocannabinoids in Δ6 desaturase deficiencies, highlighting the importance of ALA.

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