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Identification and characterization of DGA2, an acyltransferase of the DGAT1 acyl-CoA:diacylglycerol acyltransferase family in the oleaginous yeast Yarrowia lipolytica. New insights into the storage lipid metabolism of oleaginous yeasts.

Beopoulos A, Haddouche R, Kabran P, Dulermo T, Chardot T, Nicaud JM - Appl. Microbiol. Biotechnol. (2011)

Bottom Line: In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate.This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants.We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast.

View Article: PubMed Central - PubMed

Affiliation: Centre National de la Recherche Scientifique, CNRS, Micalis, Jouy-en-Josas, France. abeopoulos@grignon.inra.fr

ABSTRACT
Triacylglycerols (TAG) and steryl esters (SE) are the principal storage lipids in all eukaryotic cells. In yeasts, these storage lipids accumulate within special organelles known as lipid bodies (LB). In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate. We report here the identification of a new DAG acyltransferase gene, DGA2, homologous to the ARE genes of Saccharomyces cerevisiae. This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants. Unlike the Are proteins in S. cerevisiae, Dga2p makes a major contribution to TAG synthesis via an acyl-CoA-dependent mechanism and is not involved in SE synthesis. This enzyme appears to affect the size and morphology of LB, suggesting a direct role of storage lipid proteins in LB formation. We report that the Are1p of Y. lipolytica was essential for sterol esterification, as deletion of the encoding gene (ARE1) completely abolished SE synthesis. Unlike its homologs in yeasts, YlARE1 has no DAG acyltransferase activity. We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast.

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Observation of the phenotypes of the disrupted mutants after 24 h of culture in media containing 3% oleic acid. Fluorescence microscopy (left) with BodiPy neutral lipid staining, visual microscopy (middle), and combined photomicrographs (right) of A Po1d, B quadruple mutant, C ∆are1, D ∆dga1∆lro1, E ∆dga1∆lro1∆are1, F ∆dga2, and G ∆are1∆dga2 disrupted strains
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Fig7: Observation of the phenotypes of the disrupted mutants after 24 h of culture in media containing 3% oleic acid. Fluorescence microscopy (left) with BodiPy neutral lipid staining, visual microscopy (middle), and combined photomicrographs (right) of A Po1d, B quadruple mutant, C ∆are1, D ∆dga1∆lro1, E ∆dga1∆lro1∆are1, F ∆dga2, and G ∆are1∆dga2 disrupted strains

Mentions: The patterns of storage lipid accumulation differed between strains. The ∆dga1∆dga2∆lro1∆are1 strain (the Q4 strain) contained no storage lipids and lacked LBs at all growth phases (Figs. 4 and 7b, respectively), confirming that the four acyltransferase-coding genes were essential for storage lipid synthesis. However, the Q4 strain produced significant amounts of FFA, accounting for about 5% of dry weight at all time points, although these amounts were less than these produced by the wild-type strain.Fig. 4


Identification and characterization of DGA2, an acyltransferase of the DGAT1 acyl-CoA:diacylglycerol acyltransferase family in the oleaginous yeast Yarrowia lipolytica. New insights into the storage lipid metabolism of oleaginous yeasts.

Beopoulos A, Haddouche R, Kabran P, Dulermo T, Chardot T, Nicaud JM - Appl. Microbiol. Biotechnol. (2011)

Observation of the phenotypes of the disrupted mutants after 24 h of culture in media containing 3% oleic acid. Fluorescence microscopy (left) with BodiPy neutral lipid staining, visual microscopy (middle), and combined photomicrographs (right) of A Po1d, B quadruple mutant, C ∆are1, D ∆dga1∆lro1, E ∆dga1∆lro1∆are1, F ∆dga2, and G ∆are1∆dga2 disrupted strains
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3275733&req=5

Fig7: Observation of the phenotypes of the disrupted mutants after 24 h of culture in media containing 3% oleic acid. Fluorescence microscopy (left) with BodiPy neutral lipid staining, visual microscopy (middle), and combined photomicrographs (right) of A Po1d, B quadruple mutant, C ∆are1, D ∆dga1∆lro1, E ∆dga1∆lro1∆are1, F ∆dga2, and G ∆are1∆dga2 disrupted strains
Mentions: The patterns of storage lipid accumulation differed between strains. The ∆dga1∆dga2∆lro1∆are1 strain (the Q4 strain) contained no storage lipids and lacked LBs at all growth phases (Figs. 4 and 7b, respectively), confirming that the four acyltransferase-coding genes were essential for storage lipid synthesis. However, the Q4 strain produced significant amounts of FFA, accounting for about 5% of dry weight at all time points, although these amounts were less than these produced by the wild-type strain.Fig. 4

Bottom Line: In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate.This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants.We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast.

View Article: PubMed Central - PubMed

Affiliation: Centre National de la Recherche Scientifique, CNRS, Micalis, Jouy-en-Josas, France. abeopoulos@grignon.inra.fr

ABSTRACT
Triacylglycerols (TAG) and steryl esters (SE) are the principal storage lipids in all eukaryotic cells. In yeasts, these storage lipids accumulate within special organelles known as lipid bodies (LB). In the lipid accumulation-oriented metabolism of the oleaginous yeast Yarrowia lipolytica, storage lipids are mostly found in the form of TAG, and only small amounts of SE accumulate. We report here the identification of a new DAG acyltransferase gene, DGA2, homologous to the ARE genes of Saccharomyces cerevisiae. This gene encodes a member of the type 1 acyl-CoA:diacylglycerol acyltransferase family (DGAT1), which has not previously been identified in yeasts, but is commonly found in mammals and plants. Unlike the Are proteins in S. cerevisiae, Dga2p makes a major contribution to TAG synthesis via an acyl-CoA-dependent mechanism and is not involved in SE synthesis. This enzyme appears to affect the size and morphology of LB, suggesting a direct role of storage lipid proteins in LB formation. We report that the Are1p of Y. lipolytica was essential for sterol esterification, as deletion of the encoding gene (ARE1) completely abolished SE synthesis. Unlike its homologs in yeasts, YlARE1 has no DAG acyltransferase activity. We also reconsider the role and function of all four acyltransferase enzymes involved in the final step of neutral lipid synthesis in this oleaginous yeast.

Show MeSH