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Jia YL, Zhang Y, Xu LW, Zhang ZX, Xu YS, Ma W, Gu Y, Sun XM. Enhanced fatty acid storage combined with the multi-factor optimization of fermentation for high-level production of docosahexaenoic acid in Schizochytrium sp. Bioresour Technol 2024; 398:130532. [PMID: 38447618 DOI: 10.1016/j.biortech.2024.130532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/23/2024] [Accepted: 03/03/2024] [Indexed: 03/08/2024]
Abstract
Schizochytrium sp. hasreceived much attention for itsability to synthesize and accumulate high-level docosahexaenoic acid (DHA), which can reach nearly 40 % of total fatty acids. In this study, the titer of DHA in Schizochytrium sp. was successfully improved by enhancing DHA storage through overexpressing the diacylglycerol acyltransferase (ScDGAT2C) gene, as well as optimizing the supply of precursors and cofactors required for DHA synthesis by response surface methodology. Notably, malic acid, citric acid, and biotin showed synergistic and time-dependent effects on DHA accumulation. The maximum lipid and DHA titers of the engineered Schizochytrium sp. strain reached 84.28 ± 1.02 g/L and 42.23 ± 0.69 g/L, respectively, with the optimal concentration combination (1.62 g/L malic acid + 0.37 g/L citric acid + 8.28 mg/L biotin) were added 48 h after inoculation. This study provides an effective strategy for improving lipid and DHA production in Schizochytrium sp.
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Affiliation(s)
- Yu-Lei Jia
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Ying Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Lu-Wei Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Zi-Xu Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Ying-Shuang Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Wang Ma
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Yang Gu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China
| | - Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210000, China.
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Deng B, Kong W, Shen X, Han C, Zhao Z, Chen S, Zhou C, Bae-Jump V. The role of DGAT1 and DGAT2 in regulating tumor cell growth and their potential clinical implications. J Transl Med 2024; 22:290. [PMID: 38500157 PMCID: PMC10946154 DOI: 10.1186/s12967-024-05084-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/10/2024] [Indexed: 03/20/2024] Open
Abstract
Lipid metabolism is widely reprogrammed in tumor cells. Lipid droplet is a common organelle existing in most mammal cells, and its complex and dynamic functions in maintaining redox and metabolic balance, regulating endoplasmic reticulum stress, modulating chemoresistance, and providing essential biomolecules and ATP have been well established in tumor cells. The balance between lipid droplet formation and catabolism is critical to maintaining energy metabolism in tumor cells, while the process of energy metabolism affects various functions essential for tumor growth. The imbalance of synthesis and catabolism of fatty acids in tumor cells leads to the alteration of lipid droplet content in tumor cells. Diacylglycerol acyltransferase 1 and diacylglycerol acyltransferase 2, the enzymes that catalyze the final step of triglyceride synthesis, participate in the formation of lipid droplets in tumor cells and in the regulation of cell proliferation, migration and invasion, chemoresistance, and prognosis in tumor. Several diacylglycerol acyltransferase 1 and diacylglycerol acyltransferase 2 inhibitors have been developed over the past decade and have shown anti-tumor effects in preclinical tumor models and improvement of metabolism in clinical trials. In this review, we highlight key features of fatty acid metabolism and different paradigms of diacylglycerol acyltransferase 1 and diacylglycerol acyltransferase 2 activities on cell proliferation, migration, chemoresistance, and prognosis in tumor, with the hope that these scientific findings will have potential clinical implications.
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Affiliation(s)
- Boer Deng
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Weimin Kong
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Xiaochang Shen
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Chao Han
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
| | - Ziyi Zhao
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Shuning Chen
- Department of Gynecologic Oncology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing Maternal and Child Health Care Hospital, Beijing, People's Republic of China
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Chunxiao Zhou
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Victoria Bae-Jump
- Division of Gynecologic Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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Fu Z, Zhao T, Chu B, Gao W, Li T, Zhang Z, Li Q, Sun D. Low and high temperatures promote docosahexaenoic acid accumulation in Crypthecodinium sp. SUN by regulating the polyunsaturated fatty acid synthase pathway and the expression of saturated fatty acid preferred diacylglycerol acyltransferases. Bioresour Technol 2023; 389:129850. [PMID: 37813314 DOI: 10.1016/j.biortech.2023.129850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/06/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023]
Abstract
Low (15 °C) and high (35 °C) temperatures significantly increased DHA as a percentage of total fatty acids (TFAs) to 43.6 % and 40.46 %, respectively (1.28- and 1.18-fold of that at 25 °C, respectively). The incompleteness of the FAS pathway indicates that DHA synthesis does not occur via this pathway. Meanwhile, Comparative transcriptome analysis showed that the PUFA synthase pathway might be responsible for DHA synthesis in C. sp. SUN. Additionally, the three diacylglycerol acyltransferases all had a substrate preference for saturated fatty acid (SFA)-CoA, which also contributed to the decreased SFA and increased DHA at both low and high temperatures. Additionally, WGCNA analysis identifies key regulatory genes that may be involved in temperature-regulated DHA proportion. The findings of this study indicate the mechanisms of temperature-regulated DHA accumulation in C. sp. SUN and shed light on the manipulation of DHA proportion by changes in temperature.
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Affiliation(s)
- Zhongxiang Fu
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China; School of Life Sciences, Hebei University, Baoding 071000, China
| | - Tiantian Zhao
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
| | - Baijun Chu
- Nutrition & Health Research Institute, China National Cereals, Oils and Foodstuffs Corporation (COFCO), Beijing 102209, China
| | - Weizheng Gao
- School of Life Sciences, Hebei University, Baoding 071000, China
| | - Tong Li
- School of Life Sciences, Hebei University, Baoding 071000, China
| | - Zhao Zhang
- School of Life Sciences, Hebei University, Baoding 071000, China
| | - Qingyang Li
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China.
| | - Dongzhe Sun
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China.
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Jovičić EJ, Janež AP, Eichmann TO, Koren Š, Brglez V, Jordan PM, Gerstmeier J, Lainšček D, Golob-Urbanc A, Jerala R, Lambeau G, Werz O, Zimmermann R, Petan T. Lipid droplets control mitogenic lipid mediator production in human cancer cells. Mol Metab 2023; 76:101791. [PMID: 37586657 PMCID: PMC10470291 DOI: 10.1016/j.molmet.2023.101791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/29/2023] [Accepted: 08/08/2023] [Indexed: 08/18/2023] Open
Abstract
OBJECTIVES Polyunsaturated fatty acids (PUFAs) are structural components of membrane phospholipids and precursors of oxygenated lipid mediators with diverse functions, including the control of cell growth, inflammation and tumourigenesis. However, the molecular pathways that control the availability of PUFAs for lipid mediator production are not well understood. Here, we investigated the crosstalk of three pathways in the provision of PUFAs for lipid mediator production: (i) secreted group X phospholipase A2 (GX sPLA2) and (ii) cytosolic group IVA PLA2 (cPLA2α), both mobilizing PUFAs from membrane phospholipids, and (iii) adipose triglyceride lipase (ATGL), which mediates the degradation of triacylglycerols (TAGs) stored in cytosolic lipid droplets (LDs). METHODS We combined lipidomic and functional analyses in cancer cell line models to dissect the trafficking of PUFAs between membrane phospholipids and LDs and determine the role of these pathways in lipid mediator production, cancer cell proliferation and tumour growth in vivo. RESULTS We demonstrate that lipid mediator production strongly depends on TAG turnover. GX sPLA2 directs ω-3 and ω-6 PUFAs from membrane phospholipids into TAG stores, whereas ATGL is required for their entry into lipid mediator biosynthetic pathways. ATGL controls the release of PUFAs from LD stores and their conversion into cyclooxygenase- and lipoxygenase-derived lipid mediators under conditions of nutrient sufficiency and during serum starvation. In starving cells, ATGL also promotes the incorporation of LD-derived PUFAs into phospholipids, representing substrates for cPLA2α. Furthermore, we demonstrate that the built-up of TAG stores by acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) is required for the production of mitogenic lipid signals that promote cancer cell proliferation and tumour growth. CONCLUSION This study shifts the paradigm of PLA2-driven lipid mediator signalling and identifies LDs as central lipid mediator production hubs. Targeting DGAT1-mediated LD biogenesis is a promising strategy to restrict lipid mediator production and tumour growth.
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Affiliation(s)
- Eva Jarc Jovičić
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Anja Pucer Janež
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; Center for Explorative Lipidomics, BioTechMed-Graz, Graz, Austria
| | - Špela Koren
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Vesna Brglez
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia; Jožef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Paul M Jordan
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Jana Gerstmeier
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Duško Lainšček
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia; EN-FIST, Centre of Excellence, Ljubljana, Slovenia
| | - Anja Golob-Urbanc
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Ljubljana, Slovenia; EN-FIST, Centre of Excellence, Ljubljana, Slovenia
| | - Gérard Lambeau
- Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS), Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR7275, Valbonne Sophia Antipolis, France
| | - Oliver Werz
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Robert Zimmermann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria; BioTechMed-Graz, University of Graz, Graz, Austria
| | - Toni Petan
- Department of Molecular and Biomedical Sciences, Jožef Stefan Institute, Ljubljana, Slovenia.
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Selvaraj R, Zehnder SV, Watts R, Lian J, Das C, Nelson R, Lehner R. Preferential lipolysis of DGAT1 over DGAT2 generated triacylglycerol in Huh7 hepatocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2023; 1868:159376. [PMID: 37516308 DOI: 10.1016/j.bbalip.2023.159376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 06/26/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Two distinct diacylglycerol acyltransferases (DGAT1 and DGAT2) catalyze the final committed step of triacylglycerol (TG) synthesis in hepatocytes. After its synthesis in the endoplasmic reticulum (ER) TG is either stored in cytosolic lipid droplets (LDs) or is assembled into very low-density lipoproteins in the ER lumen. TG stored in cytosolic LDs is hydrolyzed by adipose triglyceride lipase (ATGL) and the released fatty acids are converted to energy by oxidation in mitochondria. We hypothesized that targeting/association of ATGL to LDs would differ depending on whether the TG stores were generated through DGAT1 or DGAT2 activities. Individual inhibition of DGAT1 or DGAT2 in Huh7 hepatocytes incubated with oleic acid did not yield differences in TG accretion while combined inhibition of both DGATs completely prevented TG synthesis suggesting that either DGAT can efficiently esterify exogenously supplied fatty acid. DGAT2-made TG was stored in larger LDs, whereas TG formed by DGAT1 accumulated in smaller LDs. Inactivation of DGAT1 or DGAT2 did not alter expression (mRNA or protein) of ATGL, the ATGL activator ABHD5/CGI-58, or LD coat proteins PLIN2 or PLIN5, but inactivation of both DGATs increased PLIN2 abundance despite a dramatic reduction in the number of LDs. ATGL was found to preferentially target to LDs generated by DGAT1 and fatty acids released from TG in these LDs were also preferentially used for fatty acid oxidation. Combined inhibition of DGAT2 and ATGL resulted in larger LDs, suggesting that the smaller size of DGAT1-generated LDs is the result of increased lipolysis of TG in these LDs.
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Affiliation(s)
- Rajakumar Selvaraj
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Sarah V Zehnder
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Russell Watts
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Jihong Lian
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Chinmayee Das
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Randal Nelson
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada
| | - Richard Lehner
- Group on Molecular and Cell Biology of Lipids, University of Alberta, Alberta, Canada; Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada; Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Alberta, Canada.
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6
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Li J, Chen H, Chang L, Wu C, Zhang H, Chen YQ, Chen W. Functions and substrate selectivity of diacylglycerol acyltransferases from Mortierella alpina. Appl Microbiol Biotechnol 2023; 107:5761-5774. [PMID: 37498333 DOI: 10.1007/s00253-023-12694-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
Mortierella alpina produces various polyunsaturated fatty acids in the form of triacylglycerols (TAG). Diacylglycerol acyltransferase (DGAT) catalyzes the binding of acyl-CoA to diacylglycerol to form TAG and is the key enzyme involved in TAG synthesis. A variety of DGATs are present in M. alpina; however, comparative analysis of the functional properties and substrate selectivity of these DGATs is insufficient. In this study, DGAT1 (MaDGAT1A/1B/1C) and DGAT2 (MaDGAT2A/2B) isoforms from M. alpina were analyzed and heterologously expressed in S. cerevisiae H1246. The results showed that MaDGAT1A/1B/2A/2B were able to restore TAG synthesis, and the corresponding TAG content in recombinant yeasts was 2.92 ± 0.42%, 3.62 ± 0.22%, 0.86 ± 0.34%, and 0.18 ± 0.09%, respectively. In S. cerevisiae H1246, MaDGAT1A preferred C16:1 among monounsaturated fatty acids, MaDGAT1B preferred C16:0 among saturated fatty acids (SFAs), and MaDGAT2A/2B preferred C18:0 among SFAs. Under exogenous addition of polyunsaturated fatty acids (PUFAs), MaDGAT1A and 2A preferentially assembled linoleic acid into TAG, and MaDGAT2B had substrate selectivity for eicosapentaenoic and linoleic acids in ω-6 PUFAs. In vitro, MaDGAT1A showed no obvious acyl-CoA selectivity and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred C18:1/C18:1-DAG compared with C20:4/C20:4-DAG. This study indicates that MaDGATs have the potential to be used in the production of LA/EPA-rich TAG and provide a reference for improving the production of TAGs in oleaginous fungi. KEY POINTS: • MaDGAT1A preferred C16:1 among MUFAs, MaDGAT1B and MaDGAT2A/2B preferred C16:0 and C18:0 among SFAs, respectively • MaDGAT1A/2A preferentially assembled linoleic acid into TAG, and MaDGAT2B has substrate selectivity for eicosapentaenoic acid and linoleic acid in ω-6 PUFAs • MaDGAT1A showed no obvious acyl-CoA selectivity, and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred to select C18:1/C18:1-DAG compared with C20:4/C20:4-DAG.
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Affiliation(s)
- Jun Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
| | - Lulu Chang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Chen Wu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA
| | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
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Liu K, Li J, Xing C, Yuan H, Yang J. Characterization of Auxenochlorella protothecoides acyltransferases and potential of their protein interactions to promote the enrichment of oleic acid. Biotechnol Biofuels Bioprod 2023; 16:69. [PMID: 37085915 PMCID: PMC10120206 DOI: 10.1186/s13068-023-02318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure-function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. RESULTS In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. CONCLUSIONS This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling.
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Affiliation(s)
- Kui Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinyu Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chao Xing
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongli Yuan
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinshui Yang
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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8
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Shockey J, Parchuri P, Thyssen GN, Bates PD. Assessing the biotechnological potential of cotton type-1 and type-2 diacylglycerol acyltransferases in transgenic systems. Plant Physiol Biochem 2023; 196:940-951. [PMID: 36889233 DOI: 10.1016/j.plaphy.2023.02.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 02/14/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
The chemical and physical properties of vegetable oils are largely dictated by the ratios of 4-6 common fatty acids contained within each oil. However, examples of plant species that accumulate from trace amounts to >90% of certain unusual fatty acids in seed triacylglycerols have been reported. Many of the general enzymatic reactions that drive both common and unusual fatty acid biosynthesis and accumulation in stored lipids are known, but which isozymes have evolved to specifically fill this role and how they coordinate in vivo is still poorly understood. Cotton (Gossypium sp.) is the very rare example of a commodity oilseed that produces biologically relevant amounts of unusual fatty acids in its seeds and other organs. In this case, unusual cyclopropyl fatty acids (named after the cyclopropane and cyclopropene moieties within the fatty acids) are found in membrane and storage glycerolipids (e.g. seed oils). Such fatty acids are useful in the synthesis of lubricants, coatings, and other types of valuable industrial feedstocks. To characterize the role of cotton acyltransferases in cyclopropyl fatty acid accumulation for bioengineering applications, we cloned and characterized type-1 and type-2 diacylglycerol acyltransferases from cotton and compared their biochemical properties to that of litchi (Litchi chinensis), another cyclopropyl fatty acid-producing plant. The results presented from transgenic microbes and plants indicate both cotton DGAT1 and DGAT2 isozymes efficiently utilize cyclopropyl fatty acid-containing substrates, which helps to alleviate biosynthetic bottlenecks and enhances total cyclopropyl fatty acid accumulation in the seed oil.
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Affiliation(s)
- Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, USA, 70124.
| | - Prasad Parchuri
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA, 99164
| | - Gregory N Thyssen
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, USA, 70124
| | - Philip D Bates
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA, 99164
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Zhao S, Yan F, Liu Y, Sun M, Wang Y, Li J, Zhang X, Yang X, Wang Q. Genome-wide identification and expression analysis of diacylglycerol acyltransferase genes in soybean ( Glycine max). PeerJ 2023; 11:e14941. [PMID: 36968000 PMCID: PMC10035420 DOI: 10.7717/peerj.14941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/01/2023] [Indexed: 03/29/2023] Open
Abstract
Background Soybean (Glycine max) is a major protein and vegetable oil source. In plants, diacylglycerol acyltransferase (DGAT) can exert strong flux control, which is rate-limiting for triacylglycerol biosynthesis in seed oil formation. Methods Here, we identified soybean DGAT genes via a bioinformatics method, thereby laying a solid foundation for further research on their function. Based on our bioinformatics analyses, including gene structure, protein domain characteristics, and phylogenetic analysis, 26 DGAT putative gene family members unevenly distributed on 12 of the 20 soybean chromosomes were identified and divided into the following four groups: DGAT1, DGAT2, WS/DGAT, and cytoplasmic DGAT. Results The Ka/Ks ratio of most of these genes indicated a significant positive selection pressure. DGAT genes exhibited characteristic expression patterns in soybean tissues. The differences in the structure and expression of soybean DGAT genes revealed the diversity of their functions and the complexity of soybean fatty acid metabolism. Our findings provide important information for research on the fatty acid metabolism pathway in soybean. Furthermore, our results will help identify candidate genes for potential fatty acid-profile modifications to improve soybean seed oil content. Conclusions This is the first time that in silico studies have been used to report the genomic and proteomic characteristics of DGAT in soybean and the effect of its specific expression on organs, age, and stages.
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10
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Panigrahi R, Glover JNM, Nallusamy S. A look into DGAT1 through the EM lenses. Biochim Biophys Acta Biomembr 2023; 1865:184069. [PMID: 36216097 DOI: 10.1016/j.bbamem.2022.184069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
With the advent of modern detectors and robust structure solution pipeline, cryogenic electron microscopy has recently proved to be game changer in structural biology. Membrane proteins are challenging targets for structural biologists. This minireview focuses a membrane embedded triglyceride synthesizing machine, DGAT1. Decades of research had built the foundational knowledge on this enzyme's activity. However, recently solved cryo-EM structures of this enzyme, in apo and bound form, has provided critical mechanistic insights. The flipping of the catalytic histidine is critical of enzyme catalysis. The structures explain why the enzyme has preference to long fatty acyl chains over the short forms.
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Affiliation(s)
- Rashmi Panigrahi
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
| | - J N Mark Glover
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Saranya Nallusamy
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore 641003, India.
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11
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Xu H, Li D, Hao Y, Guo X, Lu J, Zhang T. Genome-wide analysis of DGAT gene family in Perilla frutescens and functional characterization of PfDGAT2-2 and PfDGAT3-1 in Arabidopsis. Plant Sci 2022; 324:111426. [PMID: 35998725 DOI: 10.1016/j.plantsci.2022.111426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/12/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Diacylglycerol acyltransferase (DGAT) is the rate-limiting enzyme that catalyzes the final step in triacylglycerol biosynthesis, however, members of DGAT gene family of Perilla frutescens has not yet been identified and characterized. In this study, a total of 20 PfDGAT genes were identified from the genome of Perilla frutescens and were divided into four groups (PfDGAT1, PfDGAT2, PfDGAT3, PfWS/DGAT) according to their phylogenetic relationships. These were unevenly distributed across the 12 chromosomes. Sequence analysis revealed that PfDGAT members of the same subfamily have highly conserved gene structures, protein motifs and cis-acting elements in their promoters. Gene duplication analysis showed that random duplication and segmental duplication contributed to the expansion of the DGAT family in P. frutescens. RNA-seq and qRT-PCR analysis suggested that they may play a role in the growth and development of Perilla, especially in the accumulation of seed oil. Compared with the wild-type, seed length, width, and 1000-seed weight of transgenic PfDGAT2-2 and PfDGAT3-1 Arabidopsis were significantly increased, as well as the seed oil content increased by 7.36-15.83 %. Over-expression of PfDGAT2-2 could significantly increase the content of C18:3 and C20:1 in Arabidopsis, while over-expression of PfDGAT3-1 could significantly enhance the content of C18:2 and C18:3. In conclusion, in this study the characteristics and potential functions of the PfDGAT family members were elucidated. Our findings provided basic information for further functional studies and helped to increase the yield and quality of Perilla oil.
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Affiliation(s)
- Huaxiang Xu
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China
| | - Dan Li
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China
| | - Youjin Hao
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China
| | - Xi Guo
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China
| | - Junxing Lu
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China
| | - Tao Zhang
- College of Life Sciences, Chongqing Normal University, Chongqing 401331, PR China.
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12
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Gajdoš P, Urbaníková V, Vicenová M, Čertík M. Enhancing very long chain fatty acids production in Yarrowia lipolytica. Microb Cell Fact 2022; 21:138. [PMID: 35818073 PMCID: PMC9275168 DOI: 10.1186/s12934-022-01866-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/20/2022] [Indexed: 11/23/2022] Open
Abstract
Background Very long chain fatty acids (VLCFA) and their derivatives are industrially attractive compounds. The most important are behenic acid (C22:0) and erucic acid (C22:1Δ13), which are used as lubricants, and moisturizers. C22:0 and C22:1Δ13 have also potential for biofuel production. These fatty acids are conventionally obtained from plant oils. Yarrowia lipolytica is an oleaginous yeast with a long history of gene manipulations resulting in the production of industrially interesting compounds, such as organic acids, proteins, and various lipophilic molecules. It has been shown previously that it has potential for the production of VLCFA enriched single cell oils. Results The metabolism of Y. lipolytica was redesigned to achieve increased production of VLCFA. The effect of native diacylglycerol acyltransferases of this yeast YlLro1p, YlDga1p, and YlDga2p on the accumulation of VLCFA was examined. It was found that YlDga1p is the only enzyme with a beneficial effect. Further improvement of accumulation was achieved by overexpression of 3-ketoacyl-CoA synthase (TaFAE1) under 8UAS-pTEF promoter and blockage fatty acid degradation pathway by deletion of YlMFE1. The best-producing strain YL53 (Δmfe, pTEF-YlDGA1, 8UAS-pTEF-TaFAE1) produced 120 µg of very long chain fatty acids per g of produced biomass, which accounted for 34% of total fatty acids in biomass. Conclusions Recombinant strains of Y. lipolytica have proved to be good producers of VLCFA. Redesign of lipid metabolism pathways had a positive effect on the accumulation of C22:1Δ13 and C22:0, which are technologically attractive compounds.
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Affiliation(s)
- Peter Gajdoš
- Institute of Biotechnology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 81237, Bratislava, Slovak Republic.
| | - Veronika Urbaníková
- Institute of Biotechnology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 81237, Bratislava, Slovak Republic
| | - Mária Vicenová
- Institute of Biotechnology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 81237, Bratislava, Slovak Republic
| | - Milan Čertík
- Institute of Biotechnology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 81237, Bratislava, Slovak Republic
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13
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA: diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Lan C, Wang S, Zhang H, Wang Z, Wan W, Liu H, Hu Y, Cui Q, Song X. Cocktail biosynthesis of triacylglycerol by rational modulation of diacylglycerol acyltransferases in industrial oleaginous Aurantiochytrium. Biotechnol Biofuels 2021; 14:246. [PMID: 34961557 PMCID: PMC8714446 DOI: 10.1186/s13068-021-02096-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Triacylglycerol (TAG) is an important storage lipid in organisms, depending on the degree of unsaturation of fatty acid molecules attached to glycerol; it is usually used as the feedstock for nutrition or biodiesel. However, the mechanism of assembly of saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs) into TAGs remains unclear for industrial oleaginous microorganism. RESULTS Diacylglycerol acyltransferase (DGAT) is a key enzyme for TAG synthesis. Hence, ex vivo (in yeast), and in vivo functions of four DGAT2s (DGAT2A, DGAT2B, DGAT2C, and DGAT2D) in industrial oleaginous thraustochytrid Aurantiochytrium sp. SD116 were analyzed. Results revealed that DGAT2C was mainly responsible for connecting PUFA to the sn-3 position of TAG molecules. However, DGAT2A and DGAT2D target SFA and/or MUFA. CONCLUSIONS There are two specific TAG assembly routes in Aurantiochytrium. The "saturated fatty acid (SFA) TAG lane" primarily produces SFA-TAGs mainly mediated by DGAT2D whose function is complemented by DGAT2A. And, the "polyunsaturated fatty acid (PUFA) TAG lane" primarily produces PUFA-TAGs via DGAT2C. In this study, we demonstrated the functional distribution pattern of four DGAT2s in oleaginous thraustochytrid Aurantiochytrium, and provided a promising target to rationally design TAG molecular with the desired characteristics.
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Affiliation(s)
- Chuanzeng Lan
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sen Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Huidan Zhang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Zhuojun Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Weijian Wan
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
| | - Huan Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Yang Hu
- Faculty of Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaojin Song
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China.
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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15
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Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC Plant Biol 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
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Fan R, Cai G, Zhou X, Qiao Y, Wang J, Zhong H, Bo J, Miao F, Tu W, Long F, Li Z. Characterization of diacylglycerol acyltransferase 2 from Idesia polycarpa and function analysis. Chem Phys Lipids 2020; 234:105023. [PMID: 33259819 DOI: 10.1016/j.chemphyslip.2020.105023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/09/2020] [Accepted: 11/16/2020] [Indexed: 10/22/2022]
Abstract
Idesia polycarpa is an oil-producing tree native to China and Northeast Asia. The fruits of I. polycarpa which are named oil grape are unique in that they contain large amounts saturated and unsaturated lipids. Diacylglycerol acyltransferase 2 (DGAT2) is a key enzyme catalyzing the final step of triacylglyceride (TAG) synthesis. However, expression and bioinformatics of DGAT2 in I. polycarpa are still blank. In order to further understand the lipogenesis of oil grape, we contrasted seven various growth periods fruits from seed formation to seed maturation. Lipid accumulation rates and final lipid content were significantly different among the different periods. We cloned and characterized the DGAT2 gene from fruits of I. polycarpa. A partial fragment of 239 bp of IpDGAT2 was amplified by PCR. We cloned the open-reading frame (ORF) of IpDGAT2 by RACE technique. The ORF of IpDGAT2 contains 984 bp and encodes 327 amino acids. The qPCR analysis manifested that IpDGAT2 was expressed in all oil grape growing periods and expression was highest on September 20 (seed maturation). In I. polycarpa fruits the expression of IpDGAT2 was positively correlated with the lipid accumulation rates. Rhodotorula glutinis expression analysis showed that IpDGAT2 have a diacylglycerol acyltransferase bio-functional. Heterologous expression of the 35S::IpDGAT2 in Arabidopsis thaliana confirmed that the isolated IpDGAT2 could catalyze lipid synthesis. The lipid content increased by 40 % in transgenic plants relative to the control. which suggests that high lipid content fruits can be created by the overexpression of IpDGAT2 in I. polycarpa.
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Affiliation(s)
- Ruishen Fan
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Gui Cai
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Xuanyuan Zhou
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Yuxin Qiao
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Jiabao Wang
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Haoming Zhong
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Jiaxin Bo
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Fan Miao
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Wei Tu
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Feiyu Long
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China
| | - Zhouqi Li
- College of Forestry, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100 China.
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17
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Chungjatupornchai W, Fa-Aroonsawat S. Enhanced triacylglycerol production in oleaginous microalga Neochloris oleoabundans by co-overexpression of lipogenic genes: Plastidial LPAAT1 and ER-located DGAT2. J Biosci Bioeng 2020; 131:124-130. [PMID: 33069576 DOI: 10.1016/j.jbiosc.2020.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Microalgae accumulate lipid triacylglycerol (TAG), a promising feedstock for production of natural edible oils and biofuels. To make products derived from microalgal TAG economically viable, increasing TAG content and productivity are of high importance. To increase TAG content, two endogenous key enzymes of TAG biosynthesis: plastidial lysophosphatidic acid acyltransferase (NeoLPAAT1) and endoplasmic reticulum-located diacylglycerol acyltransferase 2 (NeoDGAT2) were co-overexpressed in oleaginous microalga Neochloris oleoabundans. The neutral lipid content in NeoLPAAT1-NeoDGAT2 co-overexpressing transformant detected by Nile red staining increased 2-fold without compromising cell growth. The transcriptional levels of NeoLPAAT1 and NeoDGAT2 levels were 1.9-fold higher in the transformant than wild type. Considerably higher lipid accumulation was found in the transformant than wild type: total lipid content (73.72 ± 4.17 % DCW) increased 1.6-fold, TAG content (50.63 ± 6.15 % DCW) increased 2.1-fold, total lipid productivity (16.84 ± 0.66 mg/L/day) increased 1.9-fold, and TAG productivity (11.68 ± 0.90 mg/L/day) increased 2.1-fold. Fatty acid composition was slightly altered in the transformant compared to wild type; saturated fatty acid C16:0 increased to 26% from 20%, whereas C18:0 was reduced to 7% from 14%. Long-term stability of NeoLPAAT1-NeoDGAT2 co-overexpression was observed in the transformant continuously maintained on solid medium in a period of 4 years. The results suggested that targeted engineering of genes in pathway located at different organelles should be possible in microalgal lipid metabolism.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
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Zambre VP, Khamkar SM, Gavhane DD, Khedkar SC, Chavan MR, Pandey MM, Sanap SB, Patil RB, Sawant SD. Patent landscape for discovery of promising acyltransferase DGAT and MGAT inhibitors. Expert Opin Ther Pat 2020; 30:873-896. [PMID: 32878484 DOI: 10.1080/13543776.2020.1815707] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
INTRODUCTION DGAT and MGAT enzymes play an important role in triacylglycerol (TGA) biosynthesis. Overexpression of these enzymes may lead to accumulation of TGA in adipose tissues causing development of diseases such as obesity and diabetes. High triglyceride levels increase risk factors for atherosclerosis, and increase the risk of heart attack, stroke and other heart diseases. DGAT and MGAT inhibitors are used for the treatment of such metabolic diseases. A number of DGAT and MGAT inhibitors entered into clinical and preclinical stages. However, some adverse effects are associated with them. Thus there is need to develop new, potent and safe DGAT and MGAT inhibitors. AREA COVERED In this review, the authors carefully searched patent literature and reviewed recent advances since the year 2014. Diverse chemical classes reported in the patents belonging to the category DGAT and MGAT inhibitors have been highlighted. EXPERT OPINION DGAT and MGAT inhibitors are now gaining significant importance in the treatment of metabolic diseases. Fused heterocycles with a combination of aromatic and aliphatic hydrophobic substituents could offer more potent DGAT and MGAT inhibitors. Previously reported chemical scaffolds and their DGAT and MGAT inhibitory activity could be employed as an input for some in silico studies to discover novel, potent and safe DGAT and MGAT inhibitors.
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Affiliation(s)
- Vishal P Zambre
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Shamali M Khamkar
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Dnyaneshwar D Gavhane
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Sagar C Khedkar
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Monali R Chavan
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Madhuri M Pandey
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Sonali B Sanap
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Rajesh B Patil
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
| | - Sanjay D Sawant
- Department of Pharmaceutical Chemistry, Smt. Kashibai Navale College of Pharmacy, Savitribai Phule Pune University , Pune, India
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Chawla K, Sinha K, Kaur R, Bhunia RK. Identification and functional characterization of two acyl CoA: diacylglycerol acyltransferase 1 (DGAT1) genes from forage sorghum (Sorghum bicolor) embryo. Phytochemistry 2020; 176:112405. [PMID: 32473393 DOI: 10.1016/j.phytochem.2020.112405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/31/2020] [Accepted: 05/13/2020] [Indexed: 06/11/2023]
Abstract
Elevating the lipid content in high-biomass forage crops has emerged as a new research platform for increasing energy density and improving livestock production efficiency associated with improved human health beneficial meat and milk quality. To gain insights of triacylglycerol (TAG) biosynthesis in forage sorghum, two type-1 diacylglycerol acyltransferase (designated as SbDGAT1-1 and SbDGAT1-2) were characterized for its in vivo function. SbDGAT1-2 is more abundantly expressed in embryo and bran during the early stage of the grain development in comparison to SbDGAT1-1. Heterologous expression of SbDGAT1 genes in TAG deficient H1246 strain restored the TAG accumulation capability with high substrate predilection towards 16:0, 16:1 and 18:1 fatty acids (FA). In parallel, we have identified N-terminal intrinsically disordered region (IDR) in SbDGAT1 proteins. To test the efficacy of the N-terminal region, truncated variants of SbDGAT1-1 (designated as SbDGAT1-1(39-515) and SbDGAT1-1(89-515)) were generated and expressed in yeast H1246 strain. Deletion in the N-terminal region resulted in decreased accumulation of TAG and FA (16:0 and 18:0) when compared to the SbDGAT1-1 variant expressed in yeast H1246 strain. The present study provides significant insight in forage sorghum DGAT1 gene function, useful for enhancing the green-forage TAG content through metabolic engineering.
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Affiliation(s)
- Kirti Chawla
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, 140306, Punjab, India
| | - Kshitija Sinha
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, 140306, Punjab, India
| | - Ranjeet Kaur
- Department of Genetics, University of Delhi South Campus, New Delhi, 110026, India
| | - Rupam Kumar Bhunia
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, 140306, Punjab, India.
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20
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Harwood JL. Working with Randy: The Diacylglycerol Acyltransferase Story. Lipids 2020; 55:419-423. [PMID: 32701170 DOI: 10.1002/lipd.12267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 03/29/2020] [Accepted: 06/17/2020] [Indexed: 12/19/2022]
Abstract
Vegetable oils are one of the main agricultural commodities. Demand has been increasing steadily over the last five decades and, with finite land available, it is vital that we increase productivity. My laboratory has focused on the regulation of plant lipid metabolism and, as part of this work, we identified diacylglycerol acyltransferase (DGAT) as important at regulating carbon flux during oil accumulation. This led to collaborations with Randy Weselake's research group when we quantified the importance of DGAT in oilseed rape by using flux control analysis. Later, with David Taylor, we showed that over-expression of DGAT boosted oil accumulation in field-grown crops by around 8%. These studies led to a multitude of experiments with different oil crops, such as oil palm and soybean, as well as many rewarding collaborations with Randy.
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Affiliation(s)
- John L Harwood
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, Wales, UK
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21
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Wang L, Li Q, Xia Q, Shen W, Selvaraj G, Zou J. On the Role of DGAT1 in Seed Glycerolipid Metabolic Network and Critical Stages of Plant Development in Arabidopsis. Lipids 2020; 55:457-467. [PMID: 32106336 DOI: 10.1002/lipd.12229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/09/2020] [Accepted: 02/12/2020] [Indexed: 01/07/2023]
Abstract
Studies on the model plant Arabidopsis thaliana have uncovered the identities of most enzymatic components involved in seed storage lipid biosynthesis. However, much remains to be learned on how pathway interactions operate in the seed metabolic network. In this study, we dissected seed glycerolipid molecular compositional changes in the Arabidopsis mutant deficient in diacylglycerol acyltransferase 1 (DGAT1). Our results indicate that metabolic adjustments occurred in both phosphatidylcholine synthesis and deacylation in developing seeds. Ultrastructural changes of perturbed oil and protein bodies were also evident in cotyledon parenchyma cells. To unmask the physiological and developmental role associated with DGAT1-mediated neutral lipid biosynthesis, we attempted to combine dgat1 mutation with lpcat2 that harbors a defect in lysophosphatidylcholine acyltransferase 2 (LPCAT2). Disruption in both DGAT1 and LPCAT2 led to an apparent defect in pollen development that manifested as pollen sterility. Collectively, our results highlight a role of DGAT1 in both storage lipid synthesis and plant development.
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Affiliation(s)
- Liping Wang
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Qiang Li
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.,Department of Plant Science, University of Saskatchewan, Saskatoon, SK, Canada
| | - Qun Xia
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Wenyun Shen
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Gopalan Selvaraj
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Jitao Zou
- Aquatic and Crop Resource Development, National Research Council Canada-Saskatoon, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
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22
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Liu D, Ji H, Yang Z. Functional Characterization of Three Novel Genes Encoding Diacylglycerol Acyltransferase (DGAT) from Oil-Rich Tubers of Cyperus esculentus. Plant Cell Physiol 2020; 61:118-129. [PMID: 31532486 DOI: 10.1093/pcp/pcz184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/12/2019] [Indexed: 05/06/2023]
Abstract
Cyperus esculentus is probably the only plant that is known to accumulate large amounts of oil in its tubers. However, the underlying metabolic mechanism and regulatory factors involved in oil synthesis of tubers are still largely unclear. In this study, one gene encoding type I diacylglycerol acyltransferase (DGAT) (CeDGAT1) and two genes encoding type II DGAT (CeDGAT2a and CeDGAT2b) from C. esculentus were identified and functionally analyzed. All three DGAT genes were found to be expressed in tuber, root and leaf tissues. CeDGAT1 is highly expressed in roots and leaves, whereas CeDGAT2b is dominantly expressed in tubers. Furthermore, the temporal expression pattern of CeDGAT2b is well coordinated with the oil accumulation in developing tubers. When each CeDGAT was heterologously expressed in triacylglycerol (TAG)-deficient mutant of Saccharomyces cerevisiae, Arabidopsis thaliana wild type or its TAG1 mutant with AtDGAT1 disruption, only CeDGAT2b showed the ability to restore TAG biosynthesis with lipid body formation in yeast mutant, enhance seed oil production of Arabidopsis wild type and rescue multiple seed phenotypes of TAG1 mutant. In addition, CeDGAT2b was shown to have a substrate preference for unsaturated fatty acids toward TAG synthesis. Taken together, our results indicated that CeDGAT2b from C. esculentus is an actively functional protein and is most likely the major contributor to tuber oil biosynthesis containing common fatty acids, in contrast to oil-rich seeds and fruits where DGAT1 plays a more central role than DGAT2 in oil production accumulating normal fatty acids, whereas DGAT2 is a primary regulator for oil synthesis rich in unusual fatty acids.
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Affiliation(s)
- Dantong Liu
- Key Lab of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongying Ji
- Key Lab of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenle Yang
- Key Lab of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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23
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Santín O, Galié S, Moncalián G. Directed evolution of a bacterial WS/DGAT acyltransferase: improving tDGAT from Thermomonospora curvata. Protein Eng Des Sel 2019; 32:25-32. [PMID: 31251342 DOI: 10.1093/protein/gzz011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/08/2019] [Accepted: 06/04/2019] [Indexed: 11/12/2022] Open
Abstract
Some bacteria belonging to the actinobacteria and proteobacteria groups can accumulate neutral lipids expressing enzymes of the wax ester synthase/acyl coenzyme A: diacylglycerol acyltransferase (WS/DGAT) family. tDGAT is a WS/DGAT-like enzyme from Thermomonospora curvata able to produce TAGs and WEs when heterologously expressed in Escherichia coli. In this study, a protocol for the directed evolution of bacterial lipid-producing enzymes based on fluorimetry is developed and tested. tDGAT has been successfully evolved towards the improvement of TAG production with an up to 2.5 times increase in TAG accumulation. Mutants with no ability to produce TAGs but able to accumulate waxes were also selected during the screening. The localization of the mutations that enhance TAG production in the outer surface of tDGAT points out possible new mechanisms that contribute to the activity of this family of enzymes. This Nile red-based high throughput screening provides an evolution platform for other WS/DGAT-like enzymes.
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Affiliation(s)
- Omar Santín
- Departamento de Biología Molecular, Universidad de Cantabria and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria, Santander, Spain
| | - Serena Galié
- Departamento de Biología Molecular, Universidad de Cantabria and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria, Santander, Spain
| | - Gabriel Moncalián
- Departamento de Biología Molecular, Universidad de Cantabria and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria, Santander, Spain
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24
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Kumar P, Kumar A, Sindhu J. In silico design of diacylglycerol acyltransferase-1 (DGAT1) inhibitors based on SMILES descriptors using Monte-Carlo method. SAR QSAR Environ Res 2019; 30:525-541. [PMID: 31331203 DOI: 10.1080/1062936x.2019.1629998] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/06/2019] [Indexed: 06/10/2023]
Abstract
Diabetes, obesity and other diseases related to metabolism are worldwide health problems. These syndromes can be well treated when a particular enzyme-based therapy is developed. Diacylglycerol acyltransferase (DGAT; EC 2.3.1.20) is a microsomal enzyme which is responsible for the synthesis of triglycerides from 1,2-diacylglycerol by catalyzing the acyl-CoA-dependent acylation. The obesity and type-II diabetes can be checked by the inhibition of DGAT1 enzyme. Quantitative structure-activity relationship (QSAR) modelling is an essential technique in drug design and development. To study the aspect of DGAT1 inhibitors, Monte-Carlo method-based QSAR was developed for 197 DGAT1 inhibitors. QSAR models were derived by using the optimal descriptor based on SMILES notation. Different statistical parameters including the novel index of ideality of correlation were applied to validate the generated QSAR models. Four random splits were prepared from the data set. The statistical criteria r2 = 0.8129, CCC = 0.8979 and Q2 = 0.7962 of the validation set of split 1 were the best; therefore, the developed QSAR model of split 1 was decided to be the leading model. The molecular fragments, which were promoter of endpoint increase or decrease were also determined. Thirteen new DGAT1 inhibitors were designed from the lead compound DGAT011.
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Affiliation(s)
- P Kumar
- Department of Chemistry, Kurukshetra University , Kurukshetra , India
| | - A Kumar
- Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology , Hisar , India
| | - J Sindhu
- Department of Chemsitry, COBS&H CCS Haryana Agriculture University , Hisar , India
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25
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Shockey J, Lager I, Stymne S, Kotapati HK, Sheffield J, Mason C, Bates PD. Specialized lysophosphatidic acid acyltransferases contribute to unusual fatty acid accumulation in exotic Euphorbiaceae seed oils. Planta 2019; 249:1285-1299. [PMID: 30610363 DOI: 10.1007/s00425-018-03086-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/29/2018] [Indexed: 05/20/2023]
Abstract
In vivo and in vitro analyses of Euphorbiaceae species' triacylglycerol assembly enzymes substrate selectivity are consistent with the co-evolution of seed-specific unusual fatty acid production and suggest that many of these genes will be useful for biotechnological production of designer oils. Many exotic Euphorbiaceae species, including tung tree (Vernicia fordii), castor bean (Ricinus communis), Bernardia pulchella, and Euphorbia lagascae, accumulate unusual fatty acids in their seed oils, many of which have valuable properties for the chemical industry. However, various adverse plant characteristics including low seed yields, production of toxic compounds, limited growth range, and poor resistance to abiotic stresses have limited full agronomic exploitation of these plants. Biotechnological production of these unusual fatty acids (UFA) in high yielding non-food oil crops would provide new robust sources for these valuable bio-chemicals. Previous research has shown that expression of the primary UFA biosynthetic gene alone is not enough for high-level accumulation in transgenic seed oils; other genes must be included to drive selective UFA incorporation into oils. Here, we use a series of in planta molecular genetic studies and in vitro biochemical measurements to demonstrate that lysophosphatidic acid acyltransferases from two Euphorbiaceae species have high selectivity for incorporation of their respective unusual fatty acids into the phosphatidic acid intermediate of oil biosynthesis. These results are consistent with the hypothesis that unusual fatty acid accumulation arose in part via co-evolution of multiple oil biosynthesis and assembly enzymes that cooperate to enhance selective fatty acid incorporation into seed oils over that of the common fatty acids found in membrane lipids.
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Affiliation(s)
- Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Sten Stymne
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Hari Kiran Kotapati
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Jennifer Sheffield
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Catherine Mason
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA.
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Mao X, Wu T, Kou Y, Shi Y, Zhang Y, Liu J. Characterization of type I and type II diacylglycerol acyltransferases from the emerging model alga Chlorella zofingiensis reveals their functional complementarity and engineering potential. Biotechnol Biofuels 2019; 12:28. [PMID: 30792816 PMCID: PMC6371474 DOI: 10.1186/s13068-019-1366-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/30/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND The green alga Chlorella zofingiensis has been recognized as an industrially relevant strain because of its robust growth under multiple trophic conditions and the potential for simultaneous production of triacylglycerol (TAG) and the high-value keto-carotenoid astaxanthin. Nevertheless, the mechanism of TAG synthesis remains poorly understood in C. zofingiensis. Diacylglycerol acyltransferase (DGAT) is thought to catalyze the committed step of TAG assembly in the Kennedy pathway. C. zofingiensis genome is predicted to possess eleven putative DGAT-encoding genes, the greatest number ever found in green algae, pointing to the complexity of TAG assembly in the alga. RESULTS The transcription start site of C. zofingiensis DGATs was determined by 5'-rapid amplification of cDNA ends (RACE), and their coding sequences were cloned and verified by sequencing, which identified ten DGAT genes (two type I DGATs designated as CzDGAT1A and CzDGAT1B, and eight type II DGATs designated as CzDGTT1 through CzDGTT8) and revealed that the previous gene models of seven DGATs were incorrect. Function complementation in the TAG-deficient yeast strain confirmed the functionality of most DGATs, with CzDGAT1A and CzDGTT5 having the highest activity. In vitro DGAT assay revealed that CzDGAT1A and CzDGTT5 preferred eukaryotic and prokaryotic diacylglycerols (DAGs), respectively, and had overlapping yet distinctive substrate specificity for acyl-CoAs. Subcellular co-localization experiment in tobacco leaves indicated that both CzDGAT1A and CzDGTT5 were localized at endoplasmic reticulum (ER). Upon nitrogen deprivation, TAG was drastically induced in C. zofingiensis, accompanied by a considerable up-regulation of CzDGAT1A and CzDGTT5. These two genes were probably regulated by the transcription factors (TFs) bZIP3 and MYB1, as suggested by the yeast one-hybrid assay and expression correlation. Moreover, heterologous expression of CzDGAT1A and CzDGTT5 promoted TAG accumulation and TAG yield in different hosts including yeast and oleaginous alga. CONCLUSIONS Our study represents a pioneering work on the characterization of both type I and type II C. zofingiensis DGATs by systematically integrating functional complementation, in vitro enzymatic assay, subcellular localization, yeast one-hybrid assay and overexpression in yeast and oleaginous alga. These results (1) update the gene models of C. zofingiensis DGATs, (2) shed light on the mechanism of oleaginousness in which CzDGAT1A and CzDGTT5, have functional complementarity and probably work in collaboration at ER contributing to the abundance and complexity of TAG, and (3) provide engineering targets for future trait improvement via rational manipulation of this alga as well as other industrially relevant ones.
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Affiliation(s)
- Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
| | - Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
| | - Yaping Kou
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
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Zienkiewicz K, Benning U, Siegler H, Feussner I. The type 2 acyl-CoA: diacylglycerol acyltransferase family of the oleaginous microalga Lobosphaera incisa. BMC Plant Biol 2018; 18:298. [PMID: 30477429 PMCID: PMC6257963 DOI: 10.1186/s12870-018-1510-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/29/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND Oleaginous microalgae are promising sources of energy-rich triacylglycerols (TAGs) for direct use for food, feed and industrial applications. Lobosphaera incisa is a fresh water unicellular alga, which in response to nutrient stress accumulates a high amount of TAGs with a high proportion of arachidonic acid (ARA). The final committed step of de novo TAG biosynthesis is catalyzed by acyl-CoA:diacylglycerol acyltransferases (DGATs), which add a fatty acid (FA) to the final sn-3 position of diacylglycerol (DAG). RESULTS Genome analysis revealed the presence of five putative DGAT isoforms in L. incisa, including one DGAT of type 1, three DGATs of type 2 and a single isoform of a type 3 DGAT. For LiDGAT1, LiDGAT2.1, LiDGAT2.2 and LiDGAT2.3 enzyme activity was confirmed by expressing them in the TAG-deficient yeast strain H1246. Feeding experiments of yeast transformants with fatty acids suggest a broad substrate specificity spectrum for LiDGAT1. A significant TAG production in response to exogenous ARA was found for LiDGAT2.2. Cellular localization of the four type 1 and type 2 DGATs expressed in yeast revealed that they all localize to distinct ER domains. A prominent association of LiDGAT1 with ER domains in close proximity to forming lipid droplets (LDs) was also observed. CONCLUSIONS The data revealed a distinct molecular, functional and cellular nature of type 1 and type 2 DGATs from L. incisa, with LiDGAT1 being a major contributor to the TAG pool. LiDGATs of type 2 might be in turn involved in the incorporation of unusual fatty acids into TAG and thus regulate the composition of TAG. This report provides a valuable resource for the further research of microalgae DGATs oriented towards production of fresh-water strains with higher oil content of valuable composition, not only for oil industry but also for human and animal nutrition.
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Affiliation(s)
- Krzysztof Zienkiewicz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Urs Benning
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Heike Siegler
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
- Department of Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, 37077 Goettingen, Germany
- Department of Plant Biochemistry, International Center for Advanced Studies of Energy Conversion (ICASEC), University of Goettingen, 37077 Goettingen, Germany
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28
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Shockey J, Kuhn D, Chen T, Cao H, Freeman B, Mason C. Cyclopropane fatty acid biosynthesis in plants: phylogenetic and biochemical analysis of Litchi Kennedy pathway and acyl editing cycle genes. Plant Cell Rep 2018; 37:1571-1583. [PMID: 30083958 DOI: 10.1007/s00299-018-2329-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/27/2018] [Indexed: 06/08/2023]
Abstract
This report describes the most extensive known gene discovery study from an oilseed that produces cyclopropane fatty acids, a novel industrial feedstock. Nature contains hundreds of examples of plant species that accumulate unusual fatty acids in seed triacylglycerols (TAG). Although lipid metabolic genes have been cloned from several exotic plant species, the underlying mechanisms that control the production of novel TAG species are still poorly understood. One such class of unusual fatty acids contain in-chain cyclopropane or cyclopropene functionalities that confer chemical and physical properties useful in the synthesis of lubricants, cosmetics, dyes, coatings, and other types of valuable industrial feedstocks. These cyclopropyl fatty acids, or CPFAs, are only produced by a small number of plants, primarily in the order Malvidae. Litchi chinensis is one member of this group; its seed oil contains at least 40 mol% CPFAs. Several genes, representing early, middle, and late steps in the Litchi fatty acid and TAG biosynthetic pathways have been cloned and characterized here. The tissue-specific and developmental transcript expression profiles and biochemical characteristics observed indicate which enzymes might play a larger role in Litchi seed TAG biosynthesis and accumulation. These data, therefore, provide insights into which genes likely represent the best targets for either silencing or overexpression, in future metabolic engineering strategies aimed at altering CPFA content.
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Affiliation(s)
- Jay Shockey
- Commodity Utilization Research Unit, United States Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA.
| | - David Kuhn
- Subtropical Horticulture Research Station, United States Department of Agriculture-Agricultural Research Service, Miami, FL, 33158, USA
| | - Tao Chen
- Fairy Lake Botanical Garden, Chinese Academy of Sciences, Shenzhen, 518004, Guangdong, China
| | - Heping Cao
- Commodity Utilization Research Unit, United States Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Barbara Freeman
- Subtropical Horticulture Research Station, United States Department of Agriculture-Agricultural Research Service, Miami, FL, 33158, USA
| | - Catherine Mason
- Commodity Utilization Research Unit, United States Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
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Hung YH, Buhman KK. DGAT1 deficiency disrupts lysosome function in enterocytes during dietary fat absorption. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:587-595. [PMID: 30342099 DOI: 10.1016/j.bbalip.2018.10.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/27/2018] [Accepted: 10/13/2018] [Indexed: 11/25/2022]
Abstract
Enterocytes, the absorptive cells of the small intestine, mediate the process of dietary fat absorption by secreting triacylglycerol (TAG) into circulation. When levels of dietary fat are high, TAG is stored in cytoplasmic lipid droplets (CLDs) and sequentially hydrolyzed for ultimate secretion. Mice with deficiency in acyl CoA: diacylglycerol acyltransferase 1 (Dgat1-/- mice) were previously reported to have a reduced rate of intestinal TAG secretion and abnormal TAG accumulation in enterocyte CLDs. This unique intestinal phenotype is critical to their resistance to diet-induced obesity; however, the underlying mechanism remains unclear. Emerging evidence shows that lysosomal TAG hydrolysis contributes to autophagy-mediated CLD mobilization termed lipophagy, and when disrupted results in CLD accumulation. In order to study how lipophagy contributes to the unique intestinal phenotype of Dgat1-/- mice, enterocytes from wild-type (WT) and Dgat1-/- mice were examined at 2 and 6 h after oral oil gavage. Through ultrastructural analysis we observed TAG present within autophagic vesicles (AVs) in mouse enterocytes, suggesting the role of lipophagy in intestinal CLD mobilization during dietary fat absorption. Furthermore, we found that Dgat1-/- mice had abnormal TAG accumulation within AVs and less acidic lysosomes compared to WT mice. Together these findings suggest that the delayed dietary fat absorption seen in Dgat1-/- mice is, in part, due to the dysregulated flux of autophagy-mediated CLD mobilization and impairment of lysosomal acidification in enterocytes. The present study highlights the critical role of lysosome in enterocyte CLD mobilization for proper dietary fat absorption.
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Affiliation(s)
- Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States of America
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States of America.
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Bhatt-Wessel B, Jordan TW, Miller JH, Peng L. Role of DGAT enzymes in triacylglycerol metabolism. Arch Biochem Biophys 2018; 655:1-11. [PMID: 30077544 DOI: 10.1016/j.abb.2018.08.001] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/25/2018] [Accepted: 08/02/2018] [Indexed: 01/22/2023]
Abstract
The esterification of a fatty acyl moiety to diacylglycerol to form triacylglycerol (TAG) is catalysed by two diacylglycerol O-acyltransferases (DGATs) encoded by genes belonging to two distinct gene families. The enzymes are referred to as DGAT1 and DGAT2 in order of their identification. Both proteins are transmembrane proteins localized in the endoplasmic reticulum. Their membrane topologies are however significantly different. This difference is hypothesized to give the two isozymes different abilities to interact with other proteins and organelles and access to different pools of fatty acids, thereby creating a distinction between the enzymes in terms of their role and contribution to lipid metabolism. DGAT1 is proposed to have dual topology contributing to TAG synthesis on both sides of the ER membrane and esterifying only the pre-formed fatty acids. There is evidence to suggest that DGAT2 translocates to the lipid droplet (LD), associates with other proteins, and synthesizes cytosolic and luminal apolipoprotein B associated LD-TAG from both endogenous and exogenous fatty acids. The aim of this review is to differentiate between the two DGAT enzymes by comparing the genes that encode them, their proposed topologies, the proteins they interact with, and their roles in lipid metabolism.
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Affiliation(s)
- Bhumika Bhatt-Wessel
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - T William Jordan
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - John H Miller
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand
| | - Lifeng Peng
- Centre for Biodiscovery and School of Biological Sciences, Victoria University of Wellington, New Zealand.
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Abstract
Wax esters are high-value products whose enzymatic synthesis is of increasing biotechnological interest. The fabrication of cell factories that mass-produce wax esters may provide a facile route towards a sustainable, and environment-friendly approach to a large-scale process for this commodity chemical. An expedient route for wax-ester biocatalysis may be facilitated by the action of enzymes termed wax ester synthases/diacylglycerol acyltransferases (WS/DGAT), which produce wax esters using fatty acids and alcohols as a precursor. In this work, we report the structure for a member of the WS/DGAT superfamily. The structural data in conjunction with bioinformatics and mutational analyses allowed us to identify the substrate binding pockets, and residues that may be important for catalysis. Using this information as a guide, we generated a mutant with preference towards shorter acyl-substrates. This study demonstrates the efficacy of a structure-guided engineering effort towards a WS/DGAT variant with preference towards wax esters of desired lengths.
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Abdullah HM, Chhikara S, Akbari P, Schnell DJ, Pareek A, Dhankher OP. Comparative transcriptome and metabolome analysis suggests bottlenecks that limit seed and oil yields in transgenic Camelina sativa expressing diacylglycerol acyltransferase 1 and glycerol-3-phosphate dehydrogenase. Biotechnol Biofuels 2018; 11:335. [PMID: 30574188 PMCID: PMC6299664 DOI: 10.1186/s13068-018-1326-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/30/2018] [Indexed: 05/14/2023]
Abstract
BACKGROUND Camelina sativa has attracted much interest as alternative renewable resources for biodiesel, other oil-based industrial products and a source for edible oils. Its unique oil attributes attract research to engineering new varieties of improved oil quantity and quality. The overexpression of enzymes catalyzing the synthesis of the glycerol backbone and the sequential conjugation of fatty acids into this backbone is a promising approach for increasing the levels of triacylglycerol (TAG). In a previous study, we co-expressed the diacylglycerol acyltransferase (DGAT1) and glycerol-3-phosphate dehydrogenase (GPD1), involved in TAG metabolism, in Camelina seeds. Transgenic plants exhibited a higher-percentage seed oil content, a greater seed mass, and overall improved seed and oil yields relative to wild-type plants. To further increase seed oil content in Camelina, we utilized metabolite profiling, in conjunction with transcriptome profiling during seed development to examine potential rate-limiting step(s) in the production of building blocks for TAG biosynthesis. RESULTS Transcriptomic analysis revealed approximately 2518 and 3136 transcripts differentially regulated at significant levels in DGAT1 and GPD1 transgenics, respectively. These transcripts were found to be involved in various functional categories, including alternative metabolic routes in fatty acid synthesis, TAG assembly, and TAG degradation. We quantified the relative contents of over 240 metabolites. Our results indicate major metabolic switches in transgenic seeds associated with significant changes in the levels of glycerolipids, amino acids, sugars, and organic acids, especially the TCA cycle and glycolysis intermediates. CONCLUSIONS From the transcriptomic and metabolomic analysis of DGAT1, GPD1 and DGAT1 + GPD1 expressing lines of C. sativa, we conclude that TAG production is limited by (1) utilization of fixed carbon from the source tissues supported by the increase in glycolysis pathway metabolites and decreased transcripts levels of transcription factors controlling fatty acids synthesis; (2) TAG accumulation is limited by the activity of lipases/hydrolases that hydrolyze TAG pool supported by the increase in free fatty acids and monoacylglycerols. This comparative transcriptomics and metabolomics approach is useful in understanding the regulation of TAG biosynthesis, identifying bottlenecks, and the corresponding genes controlling these pathways identified as limitations, for generating Camelina varieties with improved seed and oil yields.
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Affiliation(s)
- Hesham M. Abdullah
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 USA
- Biotechnology Department, Faculty of Agriculture, Al-Azhar University, Cairo, 11651 Egypt
- Present Address: Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Sudesh Chhikara
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 USA
- Present Address: Centre for Biotechnology, Maharshi Dayanand University, Rohtak, 124001 India
| | - Parisa Akbari
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 USA
| | - Danny J. Schnell
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 100067 India
| | - Om Parkash Dhankher
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 USA
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Zheng L, Shockey J, Guo F, Shi L, Li X, Shan L, Wan S, Peng Z. Discovery of a new mechanism for regulation of plant triacylglycerol metabolism: The peanut diacylglycerol acyltransferase-1 gene family transcriptome is highly enriched in alternative splicing variants. J Plant Physiol 2017; 219:62-70. [PMID: 29031100 DOI: 10.1016/j.jplph.2017.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/30/2017] [Accepted: 09/30/2017] [Indexed: 06/07/2023]
Abstract
Triacylglycerols (TAGs) are the most important energy storage form in oilseed crops. Diacylglycerol acyltransferase (DGAT) catalyzes the rate-limiting step of the Kennedy pathway of TAG biosynthesis. To date, little is known about the regulation of DGAT activity in peanut (Arachis hypogaea), an agronomically important oilseed crop that is cultivated in many parts of the world. In this study, seven distinct forms of type 1 DGAT (AhDGAT1.1-AhDGAT1.7) were identified, cloned, and characterized. Comparisons of the nucleotide sequences and gene structures revealed many different splicing variants of AhDGAT1, some of which displayed different organ-specific expression patterns. A representative gene (AhDGAT1.1) was transformed into wild-type tobacco and was shown to increase seed fatty acid (FA) content by 14.7%-20.9%. All seven AhDGAT1s were expressed in TAG-deficient Saccharomyces cerevisiae strain H1246; the five longest AhDGAT1 variants generated high levels of acyltransferase activity and complemented the free fatty acid lethality phenotype in this strain. The alternative splicing that gives rise to AhDGAT1.2 and AhDGAT1.4 creates predicted protein C-terminal truncations. The proteins encoded by these two variants were not active and did not complement the fatty acid sensitivity in H1246. These results were verified by visualization of intracellular lipid droplets using Nile Red staining. Collectively, the results presented here represent the first comprehensive analysis of the peanut DGAT1 gene family, which, unlike in other published plant DGAT1 sequences, shows widespread alternative splicing that may affect the expression patterns and enzyme activities of some members of the gene family.
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Affiliation(s)
- Ling Zheng
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China
| | - Jay Shockey
- United States Department of Agriculture-Agricultural Research Service, Southern Regional Research Center, New Orleans, LA 70124, USA
| | - Feng Guo
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China
| | - Lingmin Shi
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China
| | - Xinguo Li
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China
| | - Lei Shan
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China
| | - Shubo Wan
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China.
| | - Zhenying Peng
- Bio-Tech Research Center, Shandong Academy of Agricultural Science/Shandong Provincial Key Laboratory of Genetic Improvement, Ecology, and Physiology of Crops, Jinan, 250100, China.
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Yadav PK, Rajasekharan R. Cardiolipin deficiency causes triacylglycerol accumulation in Saccharomyces cerevisiae. Mol Cell Biochem 2017; 434:89-103. [PMID: 28432553 DOI: 10.1007/s11010-017-3039-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/12/2017] [Indexed: 01/05/2023]
Abstract
In yeast, the synthesis of cardiolipin (CL) and phosphatidylethanolamine (PE) occurs mainly in mitochondria. CL and PE have overlapping functions, and they are required for mitochondrial function. PE is physiologically linked with triacylglycerol (TAG) metabolism in Saccharomyces cerevisiae, involving an acyl-CoA-independent pathway through the phospholipid:diacylglycerol acyltransferase activity of the Lro1 protein. There is no report on the physiological link between CL and TAG metabolism. Here we report a metabolic link between CL and TAG accumulation in the S. cerevisiae. Our data indicated that CL deficiency causes TAG accumulation, involving an acyl-CoA-dependent pathway through the diacylglycerol acyltransferase activity of the Dga1 protein with no changes in the TAG molecular species. The DGA1 gene deletion from the CL-deficient strains reduced the TAG levels. Data from in vitro and in vivo analyses showed that CL did not affect the enzymatic activity of Dga1. Our data also showed that CL deficiency leads to the up-regulation of acetyl-CoA synthetase genes (ACS1 and ACS2) of the cytosolic pyruvate dehydrogenase bypass pathway. This study establishes a physiological link between CL and TAG metabolism in S. cerevisiae.
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Affiliation(s)
- Pradeep Kumar Yadav
- Lipidomic Centre, Department of Lipid Science, CSIR-Central Food Technological Research Institute (CFTRI), Council of Scientific and Industrial Research, Mysore, Karnataka, 570020, India
- Academy of Scientific & Innovative Research, CSIR-CFTRI, Mysore, India
| | - Ram Rajasekharan
- Lipidomic Centre, Department of Lipid Science, CSIR-Central Food Technological Research Institute (CFTRI), Council of Scientific and Industrial Research, Mysore, Karnataka, 570020, India.
- Academy of Scientific & Innovative Research, CSIR-CFTRI, Mysore, India.
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Guo X, Fan C, Chen Y, Wang J, Yin W, Wang RRC, Hu Z. Identification and characterization of an efficient acyl-CoA: diacylglycerol acyltransferase 1 (DGAT1) gene from the microalga Chlorella ellipsoidea. BMC Plant Biol 2017; 17:48. [PMID: 28222675 PMCID: PMC5319178 DOI: 10.1186/s12870-017-0995-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 02/02/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Oil in the form of triacylglycerols (TAGs) is quantitatively the most important storage form of energy for eukaryotic cells. Diacylglycerol acyltransferase (DGAT) is considered the rate-limiting enzyme for TAG accumulation. Chlorella, a unicellular eukaryotic green alga, has attracted much attention as a potential feedstock for renewable energy production. However, the function of DGAT1 in Chlorella has not been reported. RESULTS A full-length cDNA encoding a putative diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) was obtained from Chlorella ellipsoidea. The 2,142 bp open reading frame of this cDNA, designated CeDGAT1, encodes a protein of 713 amino acids showing no more than 40% identity with DGAT1s of higher plants. Transcript analysis showed that the expression level of CeDGAT1 markedly increased under nitrogen starvation, which led to significant triacylglycerol (TAG) accumulation. CeDGAT1 activity was confirmed in the yeast quadruple mutant strain H1246 by restoring its ability to produce TAG. Upon expression of CeDGAT1, the total fatty acid content in wild-type yeast (INVSc1) increased by 142%, significantly higher than that transformed with DGAT1s from higher plants, including even the oil crop soybean. The over-expression of CeDGAT1 under the NOS promoter in wild-type Arabidopsis thaliana and Brassica napus var. Westar significantly increased the oil content by 8-37% and 12-18% and the average 1,000-seed weight by 9-15% and 6-29%, respectively, but did not alter the fatty acid composition of the seed oil. The net increase in the 1,000-seed total lipid content was up to 25-50% in both transgenic Arabidopsis and B. napus. CONCLUSIONS We identified a gene encoding DGAT1 in C. ellipsoidea and confirmed that it plays an important role in TAG accumulation. This is the first functional analysis of DGAT1 in Chlorella. This information is important for understanding lipid synthesis and accumulation in Chlorella and for genetic engineering to enhance oil production in microalgae and oil plants.
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Affiliation(s)
- Xuejie Guo
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Chengming Fan
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yuhong Chen
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jingqiao Wang
- Institute of Economical Crops, Yunnan Agricultural Academy, Kunming, 65023 China
| | - Weibo Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Richard R. C. Wang
- United States Department of Agriculture, Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT 84322-6300 USA
| | - Zanmin Hu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
- Present address: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101 China
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Wei H, Shi Y, Ma X, Pan Y, Hu H, Li Y, Luo M, Gerken H, Liu J. A type-I diacylglycerol acyltransferase modulates triacylglycerol biosynthesis and fatty acid composition in the oleaginous microalga, Nannochloropsis oceanica. Biotechnol Biofuels 2017; 10:174. [PMID: 28694845 PMCID: PMC5499063 DOI: 10.1186/s13068-017-0858-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/27/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Photosynthetic oleaginous microalgae are considered promising feedstocks for biofuels. The marine microalga, Nannochloropsis oceanica, has been attracting ever-increasing interest because of its fast growth, high triacylglycerol (TAG) content, and available genome sequence and genetic tools. Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step of TAG biosynthesis in the acyl-CoA-dependent pathway. Previous studies have identified 13 putative DGAT-encoding genes in the genome of N. oceanica, but the functional role of DGAT genes, especially type-I DGAT (DGAT1), remains ambiguous. RESULTS Nannochloropsis oceanica IMET1 possesses two DGAT1 genes: NoDGAT1A and NoDGAT1B. Functional complementation demonstrated the capability of NoDGAT1A rather than NoDGAT1B to restore TAG synthesis in a TAG-deficient yeast strain. In vitro DGAT assays revealed that NoDGAT1A preferred saturated/monounsaturated acyl-CoAs and eukaryotic diacylglycerols (DAGs) for TAG synthesis, while NoDGAT1B had no detectable enzymatic activity. Assisted with green fluorescence protein (GFP) fusion, fluorescence microscopy analysis indicated the localization of NoDGAT1A in the chloroplast endoplasmic reticulum (cER) of N. oceanica. NoDGAT1A knockdown caused ~25% decline in TAG content upon nitrogen depletion, accompanied by the reduced C16:0, C18:0, and C18:1 in TAG sn-1/sn-3 positions and C18:1 in the TAG sn-2 position. NoDGAT1A overexpression, on the other hand, led to ~39% increase in TAG content upon nitrogen depletion, accompanied by the enhanced C16:0 and C18:1 in the TAG sn-1/sn-3 positions and C18:1 in the TAG sn-2 position. Interestingly, NoDGAT1A overexpression also promoted TAG accumulation (by ~2.4-fold) under nitrogen-replete conditions without compromising cell growth, and TAG yield of the overexpression line reached 0.49 g L-1 at the end of a 10-day batch culture, 47% greater than that of the control line. CONCLUSIONS Taken together, our work demonstrates the functional role of NoDGAT1A and sheds light on the underlying mechanism for the biosynthesis of various TAG species in N. oceanica. NoDGAT1A resides likely in cER and prefers to transfer C16 and C18 saturated/monounsaturated fatty acids to eukaryotic DAGs for TAG assembly. This work also provides insights into the rational genetic engineering of microalgae by manipulating rate-limiting enzymes such as DGAT to modulate TAG biosynthesis and fatty acid composition for biofuel production.
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Affiliation(s)
- Hehong Wei
- Institute for Food and Bioresource Engineering, Department of Energy and Resources Engineering and BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
| | - Ying Shi
- Institute for Food and Bioresource Engineering, Department of Energy and Resources Engineering and BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
| | - Xiaonian Ma
- Institute for Food and Bioresource Engineering, Department of Energy and Resources Engineering and BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
| | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, MA 21202 USA
| | - Ming Luo
- Guangdong Provincial Key Laboratory of Applied Botany, Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650 China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ 85212 USA
| | - Jin Liu
- Institute for Food and Bioresource Engineering, Department of Energy and Resources Engineering and BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
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Sharma M, Guleria S, Kulshrestha S. Diacylglycerol acyl transferase: A pathogenicity related gene in Colletotrichum gloeosporioides. J Basic Microbiol 2016; 56:1308-1315. [PMID: 27254647 DOI: 10.1002/jobm.201500663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 05/08/2016] [Indexed: 11/06/2022]
Abstract
To gain more insight into the molecular mechanisms of Colletotrichum gloeosporioides pathogenesis, restriction enzyme-mediated integration (REMI) mutagenesis identified the mutants of C. gloeosporioides impaired in pathogenicity. Transformants screened for defects in pathogenicity using detached leaves and fruits. Of the 20 REMI transformants tested, two mutants (H4 and H7) showed reduced pathogenicity on leaves of apple, kiwi, mango, peach, and fruits of guava, apple, and capsicum. One tagged gene from the genome sequence of mutant H4 was recovered by inverse PCR. Sequence analysis of the tagged site in mutant H4 revealed insertion in diacylglycerol acyltransferase gene which encodes diacylglycerol acyltransferase enzyme, catalyzing the steps involved in the biosynthesis of triacylglycerol, an important component of biological membranes and source of energy. Therefore, tagging of diacylglycerol acyltransferase gene in mutant H4 resulted in reduced pathogenicity, indicating possible role of this gene in pathogenicity of C. gloeosporioides.
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Affiliation(s)
- Meenakshi Sharma
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh, India
| | - Shiwani Guleria
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh, India
| | - Saurabh Kulshrestha
- Faculty of Applied Sciences and Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan, Himachal Pradesh, India
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Leamy AK, Hasenour CM, Egnatchik RA, Trenary IA, Yao CH, Patti GJ, Shiota M, Young JD. Knockdown of triglyceride synthesis does not enhance palmitate lipotoxicity or prevent oleate-mediated rescue in rat hepatocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1005-14. [PMID: 27249207 DOI: 10.1016/j.bbalip.2016.05.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 05/14/2016] [Accepted: 05/26/2016] [Indexed: 12/14/2022]
Abstract
Experiments in a variety of cell types, including hepatocytes, consistently demonstrate the acutely lipotoxic effects of saturated fatty acids, such as palmitate (PA), but not unsaturated fatty acids, such as oleate (OA). PA+OA co-treatment fully prevents PA lipotoxicity through mechanisms that are not well defined but which have been previously attributed to more efficient esterification and sequestration of PA into triglycerides (TGs) when OA is abundant. However, this hypothesis has never been directly tested by experimentally modulating the relative partitioning of PA/OA between TGs and other lipid fates in hepatocytes. In this study, we found that addition of OA to PA-treated hepatocytes enhanced TG synthesis, reduced total PA uptake and PA lipid incorporation, decreased phospholipid saturation and rescued PA-induced ER stress and lipoapoptosis. Knockdown of diacylglycerol acyltransferase (DGAT), the rate-limiting step in TG synthesis, significantly reduced TG accumulation without impairing OA-mediated rescue of PA lipotoxicity. In both wild-type and DGAT-knockdown hepatocytes, OA co-treatment significantly reduced PA lipid incorporation and overall phospholipid saturation compared to PA-treated hepatocytes. These data indicate that OA's protective effects do not require increased conversion of PA into inert TGs, but instead may be due to OA's ability to compete against PA for cellular uptake and/or esterification and, thereby, normalize the composition of cellular lipids in the presence of a toxic PA load.
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Brandt C, McFie PJ, Stone SJ. Biochemical characterization of human acyl coenzyme A: 2-monoacylglycerol acyltransferase-3 (MGAT3). Biochem Biophys Res Commun 2016; 475:264-70. [PMID: 27184406 DOI: 10.1016/j.bbrc.2016.05.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/12/2016] [Indexed: 01/31/2023]
Abstract
BACKGROUND MGAT3 catalyzes the synthesis of 1,2-diacylglycerol from 2-monoacylglycerol in an acyl CoA-dependent reaction. Although initially identified as an MGAT enzyme, MGAT3 is more closely related to DGAT2 than to MGAT1 and MGAT2. Furthermore, MGAT3 possesses both DGAT and MGAT activities, in vitro. MGAT3 is almost exclusively expressed in the small intestine in humans, suggesting that it has a role in dietary fat absorption. Although identified many years ago, little information is available regarding the contribution of MGAT3 to triacylglycerol biosynthesis. RESULTS This study confirmed the initial observations that MGAT3 possessed both MGAT and DGAT activities. When expressed in cells in culture, MGAT3 stimulated lipid droplet growth, but unlike DGAT2, does not become concentrated around the lipid droplet surface. We also characterized the MGAT activity of an MGAT3 mutant in which a conserved cysteine was changed to a tyrosine residue. Lastly, although they share significant sequence identity, MGAT3 is a much more stable protein than DGAT2, yet they are both polyubiquitinated and degraded through ER-associated degradation by the proteasome. CONCLUSION Our findings provide additional evidence that MGAT3 likely functions as a TG synthase in cells.
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Hung CH, Ho MY, Kanehara K, Nakamura Y. Functional study of diacylglycerol acyltransferase type 2 family in Chlamydomonas reinhardtii. FEBS Lett 2013; 587:2364-70. [PMID: 23770092 DOI: 10.1016/j.febslet.2013.06.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 05/28/2013] [Accepted: 06/04/2013] [Indexed: 01/25/2023]
Abstract
Algal triacylglycerol biosynthesis is of increasing interest for potential biodiesel production. A model microalga, Chlamydomonas, has multiple isoforms of diacylglycerol acyltransferase type 2 (DGTT) catalyzing the final step of triacylglycerol biosynthesis; however, the functions of the isoforms are poorly understood. Here, we performed heterologous complementation assay of Chlamydomonas DGTT1 to 4 in a yeast mutant defective in triacylglycerol biosynthesis. DGTT1, 2 and 3 but not 4 complemented the phenotype, including triacylglycerol levels. Interestingly, complementation by DGTT2 increased triacylglycerol content by 9-fold.
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Affiliation(s)
- Chun-Hsien Hung
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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