Zebrafish cDNA Encoding Multifunctional Fatty Acid Elongase Involved in Production of Eicosapentaenoic (20:5n-3) and Docosahexaenoic (22:6n-3) Acids

Agaba, Morris; Tocher, Douglas R.; Dickson, Cathryn A.; Dick, James R.; Teale, A.J.

doi:10.1007/s10126-003-0029-1

Cited by 130 publications

(86 citation statements)

References 34 publications

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“…The results were consistent with the well-established observations of lack of PUFA elongase activity in S. cerevisiae [21,22]. The FA compositions of yeast transformed with the pYES2-ELOVL construct and grown in the presence of different substrates were shown in Figure 4.…”

Section: Functional Characterizationsupporting

confidence: 90%

Molecular Cloning and Functional Characterisation of a Polyunsaturated Fatty Acid Elongase in a Marine Bivalve Crassostrea angulata

Zhang¹,

Liu²,

Cheng³

et al. 2018

JFNR

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The elongases of fatty acids (ELO) are essential for long chain polyunsaturated fatty acid (LC-PUFA) biosynthesis, and their activities depend on the substrates. The full length cDNA of Crassostrea angulata ELO (CaELO) was cloned by RACE PCR and its function was confirmed. The CaELO encodes a polypeptide of 309 amino acid residues, which containes a histidine box HXXHH motif conserved in all elongases and shares high similarity to the elongases of Chlamys nobilis and Octopus vulgaris. Phylogenetic analysis showed that the putative elongase was placed in the same group with ELOVL2 and ELOVL5, which have been demonstrated to be critical enzymes participating in the biosynthesis of PUFAs in vertebrates. When expressed in Saccharomyces cerevisiae, CaELO was able to elongate n-3 and n-6 PUFA substrates with chain lengths of C18 and C20, indicating that the CaELO had similar substrate specificities to vertebrate ELOVL5. CaELO had lower activity to elongate monounsaturated fatty acids, but had not activity to saturated fatty acids. Interestingly, the conversion rate of PUFAs depended on the length of carbon chain, the number of double bond, and n-3 / n-6 series in the species.

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Section: Functional Characterizationsupporting

confidence: 90%

Molecular Cloning and Functional Characterisation of a Polyunsaturated Fatty Acid Elongase in a Marine Bivalve Crassostrea angulata

Zhang¹,

Liu²,

Cheng³

et al. 2018

JFNR

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“…As the first step towards generation of transgenic marine fish, we cloned and over-expressed a masu salmon (Oncorhynchus masou) MELO gene in the model species zebrafish (Danio rerio). Based on the predicted topology, consensus sequences, and sequence homologies, MELO are in excellent agreement with expected structural traits of elongases (Leonard et al, 2002;Hasting et al, 2004;Meyer et al, 2004;Agaba et al, 2004Agaba et al, , 2005.…”

Section: Transgenic Fish Carrying Melo Genesupporting

confidence: 55%

Over-Expression of Gene Encoding Fatty Acid Metabolic Enzymes in Fish

Alimuddin

Yoshizaki

Takeuchi

et al. 2008

Indonesian Aquaculture Journal

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Eicosapentaenoic acid (EPA, and docosahexaenoic acid (DHA, 22:6n-3) have important nutritional benefits in humans. EPA and DHA are mainly derived from fish, but the decline in the stocks of major marine capture fishes could result in these fatty acids being consumed less. Farmed fish could serve as promising sources of EPA and DHA, but they need these fatty acids in their diets. Generation of fish strains that are capable of synthesizing enough amounts of EPA/DHA from the conversion of α-linolenic acid (LNA, 18:3n-3) rich oils can supply a new EPA/DHA source. This may be achieved by over-expression of genes encoding enzymes involved in HUFA biosynthesis. In aquaculture, the successful of this technique would open the possibility to reduce the enrichment of live food with fish oils for marine fish larvae, and to completely substitute fish oils with plant oils without reducing the quality of flesh in terms of EPA and DHA contents. Here, three genes, i.e. Δ6-desaturase-like (OmΔ6FAD), Δ5-desaturase-like (OmΔ5FAD) and elongase-like (MELO) encoding EPA/ DHA metabolic enzymes derived from masu salmon (Oncorhynchus masou) were individually transferred into zebrafish (Danio rerio) as a model to increase its ability for synthesizing EPA and DHA. Fatty acid analysis showed that EPA content in whole body of the second transgenic fish generation over-expressing OmΔ6FAD gene was 1.4 fold and that of DHA was 2.1 fold higher (P<0.05) than those in non-transgenic fish. The EPA content in whole body of transgenic fish over-expressing OmΔ5FAD gene was 1.21-fold, and that of DHA was 1.24-fold higher (P<0.05) than those in nontransgenic fish. The same patterns were obtained in transgenic fish over-expressing MELO gene. EPA content was increased by 1.30-fold and DHA content by 1.33-fold higher (P<0.05) than those in non-transgenic fish. The results of studies demonstrated that fatty acid content of fish can be enhanced by over-expressing gene encoding enzymes involved in fatty acid biosynthesis, and perhaps this could be applied to tailor farmed fish as even better sources of valuable human food.

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“…The current study does not identify sequence differences between the chicken and rat Elovl5, which may explain their different abilities to elongate DPA. Also, it does not identify sequence variability which could explain the higher activity of the chicken Elovl5 which converts 20% DPA to 24:5n-3 compared with Elovl5 DPA conversion activities of 5-9% in sea bream, zebrafi sh, cobia, and Atlantic bluefi n tuna ( 8,10,11,21 ). The sites within these Elovl5 enzymes that confer DPA elongation ability may not be within the transmembrane regions examined in this study with rat enzymes.…”

Section: Discussionmentioning

confidence: 77%

Molecular basis for differential elongation of omega-3 docosapentaenoic acid by the rat Elovl5 and Elovl2

Gregory

Cleland

James

2013

Journal of Lipid Research

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and Elovl2, which have been overlooked as regulators of DHA synthesis. Using a yeast expression system, it was apparent that the substrate specifi cities of the two rat elongases had some overlap, but that only Elovl2 could convert endogenously formed C 22 PUFA docosapentaenoic acid (DPA) (22:5n-3) to 24:5n-3, which is the penultimate precursor of DHA ( 5 ). Elovl2 performs the sequential elongation of EPA to DPA followed by further elongation to 24:5n-3.Thus, Elovl2 is crucial for DHA synthesis at least in the rat where Elovl5 cannot elongate DPA to 24:5n-3 ( 5 ). This probably explains the poor or absent ability to produce DHA in species that do not have detectable Elovl2 such as barramundi ( 6, 7 ) or in species such as the rat in which Elovl2 is expressed at low levels ( 5 ). However, there is not an absolute Elovl2 dependence for DHA synthesis in all species because the sea bream, cobia, Atlantic bluefi n tuna, and chicken Elovl5 have a small but measurable ability to elongate DPA ( 8-11 ). In order to better understand the potential for these elongases to be involved in DHA synthesis, we have sought the molecular reasons for the differences between Elovl5 and Elovl2 in their ability to elongate DPA to 24:5n-3.Purifi cation of membrane-bound elongases to determine the substrate binding pocket has proven to be unsuccessful ( 12 ). However, chimeric elongase proteins from yeast ( 13 ), the moss Physcomitrella patens ( 14 ), and the fungi Pythium irregulare and Phytophthore infestans ( 15 ) have been used to investigate the regions involved in C 18 and C 20 PUFA substrate specifi city and product chain length determination. Therefore, we have constructed a series of rat Elovl2/Elovl5 chimeras and point mutations to examine the Elovl2 residues responsible for DPA substrate specifi city using a yeast expression system.Abstract Functional characterization of the rat elongases, Elovl5 and Elovl2, has identifi ed that Elovl2 is crucial for omega-3 docosahexaenoic acid (DHA) (22:6n-3) synthesis. While the substrate specifi cities of the rat elongases had some overlap, only Elovl2 can convert the C 22 omega-3 PUFA docosapentaenoic acid (DPA) (22:5n-3) to 24:5n-3, which is the penultimate precursor of DHA. In order to better understand the potential for these elongases to be involved in DHA synthesis, we have examined the molecular reasons for the differences between Elovl5 and Elovl2 in their ability to elongate DPA to 24:5n-3. We identifi ed a region of heterogeneity between Elovl5 and Elovl2 spanning transmembrane domains 6 and 7. Using a yeast expression system, we examined a series of Elovl2/Elovl5 chimeras and point mutations to identify Elovl2 residues within this region which are responsible for DPA substrate specifi city. The results indicate that the cysteine at position 217 in Elovl2 and a tryptophan at the equivalent position in Elovl5 explain their differing abilities to elongate DPA to 24:5n-3. Further studies confi rmed that Elovl2 C217 is a critical residue for elongation of DPA at the level observed i...

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Zebrafish cDNA Encoding Multifunctional Fatty Acid Elongase Involved in Production of Eicosapentaenoic (20:5n-3) and Docosahexaenoic (22:6n-3) Acids

Abstract: elongation steps required. The zebrafish enzyme was also able to elongate monounsaturated and saturated fatty acids, and thus demonstrates a greater level of promiscuity in terms of substrate use than any elongase enzyme described previously.3

Cited by 130 publications

References 34 publications

Molecular Cloning and Functional Characterisation of a Polyunsaturated Fatty Acid Elongase in a Marine Bivalve <i>Crassostrea</i><i> </i><i>angulata</i>

Molecular Cloning and Functional Characterisation of a Polyunsaturated Fatty Acid Elongase in a Marine Bivalve <i>Crassostrea</i><i> </i><i>angulata</i>

Over-Expression of Gene Encoding Fatty Acid Metabolic Enzymes in Fish

Molecular basis for differential elongation of omega-3 docosapentaenoic acid by the rat Elovl5 and Elovl2

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