Poster: Lipids & Related Molecules
Abs #
862: Analysis of the expression of the gene for CTP:phosphorylethanolamine cytidylyltransferase in Arabidopsis thaliana
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Presenter: |
Mizoi, Junya , ss27198@mail.ecc.u-tokyo.ac.jp |
Authors | Mizoi, Junya (A) Inatsugi, Rie (A) Nakamura, Masanobu (A) Nishida, Ikuo (A) | | Affiliations: |
(A): Department of Biological Sciences, Graduate School of Science, The University of Tokyo
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In plants, phosphatidylethanolamine (PE) is synthesized via three metabolic pathways, i.e. the nucleotide pathway (or the CDP-ethanolamine pathway), the phosphatidylserine decarboxylation pathway and the base-exchange pathway, and the nucleotide pathway is thought to be the major pathway. CTP:phosphorylethanolamine cytidylyltransferase (ECT; EC 2.7.7.14) is the rate-limiting enzyme in the nucleotide pathway and, hence, regulates the PE biosynthesis in plants.
Arabidopsis thaliana, contains a single gene for ECT designated AtECT1 (At2g38670). To investigate the expression of AtECT1 in various parts of Arabidopsis, we herein constructed a transgenic plant that expresses an AtECT1 promoter-GUS fusion gene. We found that GUS staining was detected in veins of rosette leaves, vascular systems of shoots and petioles, and in flower organs such as anther and stigma. By contrast, GUS staining was scarcely detected in the mesophyll of rosette leaves. All these results suggested that AtECT1 might have specialized function(s) in some tissues of Arabidopsis.
In accordance with the previous report that PE content increased in plasma membranes of Arabidopsis at low temperatures, expression of GUS activity was enforced by low temperature in rosette leaves of the above transgenic plant. We confirmed further by RNA gel blot analysis, immunoblot analysis and activity measurement that expression of AtECT1 was enhanced by low temperature and that the enhancement was regulated at the transcript level. We will discuss the possible role of AtECT1 in cold-acclimated Arabidopsis with regards to the biosynthesis and turnover of polyunsaturated molecular species of PE at low temperatures. (Supported in part by a grant form PROBRAIN).
