Abstract
In mammalian cells, Sprecher has proposed that the synthesis of long-chain PUFA from the 20-carbon substrates involves two consecutive elongation steps, a Δ6-desaturation step followed by retroconversion (Sprecher, H., Biochim. Biophys. Acta 1486, 219–231, 2000). We searched the database using the translated sequence of human elongase ELOVL5, whose encoded enzyme elongates monounsaturated and polyunsaturated FA, as a query to identify the enzyme(s) involved in elongation of very long chain PUFA. The database search led to the isolation of two cDNA clones from human and mouse. These clones displayed deduced amino acid sequences that had 56.4 and 58% identity, respectively, to that of ELOVL5. The open reading frame of the human clone (ELOVL2) encodes a 296-amino acid peptide, whereas the mouse clone (Elovl2) encodes a 292-amino acid peptide. Expression of these open reading frames in baker's yeast, Saccharomyces cerevisiae, demonstrated that the encoded proteins were involved in the elongation of both 20-and 22-carbon long-chain PUFA, as determined by the conversion of 20∶4n−6 to 22∶4n−6, 22∶4n−6 to 24∶4n−6, 20∶5n−3 to 22∶5n−3, and 22∶5n−3 to 24∶5n−3. The elongation activity of the mouse Elovl2 was further demonstrated in the transformed mouse L cells incubated with long-chain (C20-and C22-carbon) n−6 and n−3 PUFA substrates by the significant increase in the levels of 24∶4n−6 and 24∶5n−3, respectively. This report demonstrates the isolation and identification of two mammalian genes that encode very long chain PUFA specific elongation enzymes in the Sprecher pathway for DHA synthesis.
Similar content being viewed by others
Abbreviations
- AA:
-
arachidonic acid (20∶4n−6)
- ALA:
-
α-linolenic acid (18∶3n−3)
- LA:
-
linoleic acid (18∶2n−6)
- m-ELO:
-
mouse L cells cloned with mouse elongase gene Elov12
References
Samuelsson, B. (1983) From Studies of Biochemical Mechanism to Novel Biological Mediators: Prostaglandin Endoperoxides, Thromboxanes, and Leukotrienes. Nobel Lecture, 8 December 1982, Biosci. Rep. 3, 791–813.
Carlson, S.E., Werkman, S.H., Peeples, J.M., Cooke, R.J., and Tolley, E.A. (1993) Arachidonic Acid Status Correlates with First Year Growth in Preterm Infants, Proc. Natl. Acad. Sci. USA 90, 1073–1077.
Crawford, M.A., Costeloe, K., Ghebremeskel, K., Phylactos, A., Skirvin, L., and Stacey, F. (1997) Are Deficits of Arachidonic and Docosahexaenoic Acids Responsible for the Neural and Vascular Complications of Preterm Babies? Am. J. Clin. Nutr. 66, 1032S-1041S.
Uauy, R., Peirano, P., Hoffman, D., Mena, P., Birch, D., and Birch, E. (1996) Role of Essential Fatty Acids in the Function of the Developing Nervous System, Lipids 31, S167-S176.
Horrobin, D.F. (1992) Nutritional and Medical Importance of gamma-Linolenic Acid, Prog. Lipid Res. 31, 163–194.
Poulos, A. (1995) Very Long Chain Fatty Acids in Higher Animals—A Review, Lipids 30, 1–14.
Voss, A., Reinhart, M., Sankarappa, S., and Sprecher, H. (1991) The Metabolism of 7,10,13,16,19-Docosapentaenoic Acid to 4,7,10,13,16,19-Docosahexaenoic Acid in Rat Liver Is Independent of a 4-Desaturase, J. Biol. Chem. 266, 19995–20000.
Wang, N., and Anderson, R.E. (1993) Synthesis of Docosahexaenoic Acid by Retina and Retinal Pigment Epithelium, Biochemistry 32, 13703–13709.
Mohammod, B.S., Sankarappa, S., Geiger, M., and Sprecher, H. (1995) Reevaluation of the Pathway for the Metabolism of 7,10,13,16-Docosatetraenoic Acid to 4,7,10,13,16-Docosapentaenoic Acid in Rat Liver, Arch. Biochem. Biophys. 317, 179–184.
Moore, S.A., Hurt, E., Yoder, E., Sprecher, H., and Spector, A.A. (1995) Docosahexaenoic Acid Synthesis in Human Skin Fibroblasts Involves Peroxisomal Retroconversion of Tetracosahexaenoic Acid, J. Lipid Res. 36, 2433–2443.
Sprecher, H. (2000) Metabolism of Highly Unsaturated n−3 and n−6 Fatty Acids, Biochim. Biophys. Acta 1486, 219–231.
Delton-Vandenbroucke, I., Grammas, P., and Anderson, R.E. (1997) Polyunsaturated Fatty Acid Metabolism in Retinal and Cerebral Microvascular Endothelial Cells, J. Lipid Res. 38, 147–159.
Caruso, D., Risé, P., Galella, G., Regazzoni, C., Toia, A., Galli, G., and Galli, C. (1994) Formation of 22 and 24 Carbon 6-Desaturated Fatty Acids from Exogenous Deuterated Arachidonic Acid Is Activated in THP-1 Cells at High Substrate Concentrations, FEBS Lett. 343, 195–199.
Sprecher, H. (1996) New Advances in Fatty-Acid Biosynthesis; Nutrition 12, S5-S7.
Marzo, I., Alava, M.A., Piñeiro, A., and Naval, J. (1996) Biosynthesis of Docosahexaenoic Acid in Human Cells: Evidence That Two Different Δ6-Desaturase Activities May Exist, Biochim. Biophys. Acta 1301, 263–272.
Luthria, D.L., and Sprecher, H. (1997) Studies to Determine if Rat Liver Contains Multiple Chain Elongating Enzymes, Biochim. Biophys. Acta 1346, 221–230.
Sprecher, H., Luthria, D.L., Mohammed, B.S., and Baykousheva, S.P. (1995) Reevaluation of the Pathways for the Biosynthesis of Polyunsaturated Fatty Acids, J. Lipid Res. 36, 2471–2477.
Su, H.-M., Moser, A.B., Moser, H.W., and Watkins, P.A. (2001) Peroxisomal Straight-Chain Acyl-CoA Oxidase and D-Bifunctional Protein Are Essential for the Retroconversion Step in Docosahexaenoic Acid Synthesis, J. Biol. Chem. 276, 38115–38120.
Leonard, A.E., Bobik, E.G., Dorado, J., Kroeger, P.E., Chuang, L.-T., Thurmond, J.M., Parker-Barnes, J.M., Das, T., Huang, Y.-S., and Mukerji, P. (2000) Cloning of a Human cDNA Encoding a Novel Enzyme Involved in the Elongation of Long-Chain Polyunsaturated Fatty Acids, Biochem. J. 350, 765–770.
Tvrdik, P., Westerberg, R., Silve, S., Asadi, A., Jakobsson, A., Cannon, B., Loison, G., and Jacobsson, A. (2000) Role of a New Mammalian Gene Family in the Biosynthesis of Very Long Chain Fatty Acids and Sphingolipids, J. Cell Biol. 149, 707–717.
Oh, C.-S., Toke, D.A., Mandala, S., and Martin, C.E. (1997) ELO2 and ELO3, Homologues of the Saccharomyces cerevisiae ELO1 Gene, Function in Fatty Acid Elongation and Are Required for Sphingolipid Formation, J. Biol. Chem. 272, 17376–17384.
Knutzon, D.S., Thurmond, J.M., Huang, Y.-S., Chaudhary, S., Bobik, E.G., Jr., Chan, G.M., Kirchner, S.J., and Mukerji, P. (1998) Identification of Δ5-Desaturase from Mortierella alpina by Heterologous Expression in Bakers' Yeast and Canola, J. Biol. Chem. 273, 29360–29366.
Wigler, M., Pellicer, A., Silverstein, S., and Axel, R. (1978) Biochemical Transfer of Single-Copy Eucaryotic Genes Using Total Cellular DNA as Donor, Cell 14, 725–731.
Kelder, B., Richmond, C., Stavnezer, E., List, E.O., and Kopchick, J.J. (1997) Production, Characterization, and Functional Activities of v-Ski in Cultured Cells, Gene 202, 15–21.
Huang, Y.-S., Chaudhary, R., Thurmond, J.M., Bobik, E.G., Jr., Yuan, L., Chan, G.M., Kirchner, S., Mukerji, P., and Knutzon, D.S. (1999) Cloning of Δ12-and Δ6-Desaturases from Mortierella alpina and Recombinant Production of γ-Linolenic acid in Saccharomyces cerevisiae, Lipids 34, 649–659.
Kelder, B., Mukerji, P., Kirchner, S., Hovanec, G., Leonard, A.E., Chuang, L.-T., Kopchick, J.J., and Huang, Y.-S. (2001) Expression of Fungal Desaturase Genes in Cultured Mammalian Cells, Mol. Cell. Biochem. 219, 7–11.
Innis, S.M., Sprecher, H., Hachey, D., Edmond, J., and Anderson, R.E. (1999) Neonatal Polyunsaturated Fatty Acid Metabolism, Lipids 34, 139–149.
Author information
Authors and Affiliations
Corresponding author
About this article
Cite this article
Leonard, A.E., Kelder, B., Bobik, E.G. et al. Identification and expression of mammalian long-chain PUFA elongation enzymes. Lipids 37, 733–740 (2002). https://doi.org/10.1007/s11745-002-0955-6
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11745-002-0955-6