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Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme

Alkenones are unusual long-chain neutral lipids that were first identified in oceanic sediments. Currently they are regarded as reliable palaeothermometers, since their unsaturation status changes depending on temperature. These molecules are synthesised by specific haptophyte algae and are stored i...

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Autores principales: Endo, Hirotoshi, Hanawa, Yutaka, Araie, Hiroya, Suzuki, Iwane, Shiraiwa, Yoshihiro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060089/
https://www.ncbi.nlm.nih.gov/pubmed/30046151
http://dx.doi.org/10.1038/s41598-018-29482-8
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author Endo, Hirotoshi
Hanawa, Yutaka
Araie, Hiroya
Suzuki, Iwane
Shiraiwa, Yoshihiro
author_facet Endo, Hirotoshi
Hanawa, Yutaka
Araie, Hiroya
Suzuki, Iwane
Shiraiwa, Yoshihiro
author_sort Endo, Hirotoshi
collection PubMed
description Alkenones are unusual long-chain neutral lipids that were first identified in oceanic sediments. Currently they are regarded as reliable palaeothermometers, since their unsaturation status changes depending on temperature. These molecules are synthesised by specific haptophyte algae and are stored in the lipid body as the main energy storage molecules. However, the molecular mechanisms that regulate the alkenone biosynthetic pathway, especially the low temperature-dependent desaturation reaction, have not been elucidated. Here, using an alkenone-producing haptophyte alga, Tisochrysis lutea, we show that the alkenone desaturation reaction is catalysed by a newly identified desaturase. We first isolated two candidate desaturase genes and found that one of these genes was drastically upregulated in response to cold stress. Gas chromatographic analysis revealed that the overexpression of this gene, named as Akd1 finally, increased the conversion of di-unsaturated C(37)-alkenone to tri-unsaturated molecule by alkenone desaturation, even at a high temperature when endogenous desaturation is efficiently suppressed. We anticipate that the Akd1 gene will be of great help for elucidating more detailed mechanisms of temperature response of alkenone desaturation, and identification of active species contributing alkenone production in metagenomic and/or metatranscriptomic studies in the field of oceanic biogeochemistry.
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spelling pubmed-60600892018-07-31 Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme Endo, Hirotoshi Hanawa, Yutaka Araie, Hiroya Suzuki, Iwane Shiraiwa, Yoshihiro Sci Rep Article Alkenones are unusual long-chain neutral lipids that were first identified in oceanic sediments. Currently they are regarded as reliable palaeothermometers, since their unsaturation status changes depending on temperature. These molecules are synthesised by specific haptophyte algae and are stored in the lipid body as the main energy storage molecules. However, the molecular mechanisms that regulate the alkenone biosynthetic pathway, especially the low temperature-dependent desaturation reaction, have not been elucidated. Here, using an alkenone-producing haptophyte alga, Tisochrysis lutea, we show that the alkenone desaturation reaction is catalysed by a newly identified desaturase. We first isolated two candidate desaturase genes and found that one of these genes was drastically upregulated in response to cold stress. Gas chromatographic analysis revealed that the overexpression of this gene, named as Akd1 finally, increased the conversion of di-unsaturated C(37)-alkenone to tri-unsaturated molecule by alkenone desaturation, even at a high temperature when endogenous desaturation is efficiently suppressed. We anticipate that the Akd1 gene will be of great help for elucidating more detailed mechanisms of temperature response of alkenone desaturation, and identification of active species contributing alkenone production in metagenomic and/or metatranscriptomic studies in the field of oceanic biogeochemistry. Nature Publishing Group UK 2018-07-25 /pmc/articles/PMC6060089/ /pubmed/30046151 http://dx.doi.org/10.1038/s41598-018-29482-8 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Endo, Hirotoshi
Hanawa, Yutaka
Araie, Hiroya
Suzuki, Iwane
Shiraiwa, Yoshihiro
Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title_full Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title_fullStr Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title_full_unstemmed Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title_short Overexpression of Tisochrysis lutea Akd1 identifies a key cold-induced alkenone desaturase enzyme
title_sort overexpression of tisochrysis lutea akd1 identifies a key cold-induced alkenone desaturase enzyme
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6060089/
https://www.ncbi.nlm.nih.gov/pubmed/30046151
http://dx.doi.org/10.1038/s41598-018-29482-8
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