1998 Fiscal Year Final Research Report Summary
Gene Structure and Expression of Lysophosphatidate Acyltransferase in Oil Plants
| Project/Area Number |
08660117
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
応用微生物学・応用生物化学
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| Research Institution | Kyoto Prefectural University |
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Principal Investigator |
ICHIHARA Kenichi Kyoto Prefectural University, Department of Agriculture, Associate Professor, 農学部, 助教授 (50046512)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Kunisuke Kyoto Prefectural University, Department of Agriculture, Professor, 農学部, 教授 (90027194)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Lysophosphatidate / Acyltransferase / Oil Plants |
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| Research Abstract |
A full-length cDNA encoding lysophosphatidate acyltransferase was isolated from a cDNA library prepared from developing seeds of a cauliflower (Brassica oleracea) line using polymerase chain reaction with degenerate oligonucleotides corresponding to conserved amino acid sequences in known lysophosphatidate acyltransferases of other organisms including higher plants. The isolated cDNA encoded a protein of 390 amino acid residues with a molecular weight of 43,600. The putative protein has two hydrophobic domains at the carboxyl end and conservative amino acid sequences found in other lysophosphatidate acyltransferases. The amino acid homology is 67% between the enzymes of the cauliflower line and maize.
Membranes of Escherichia coli JMlO9 that expressed the cauliflower cDNA catalyzed the esterification of lysophosphatidate with acyl-CoA specificity different from that of native E.coli membranes, and utilized saturated acyl-CoAs preferentially. Developing seeds of the cauliflower line showed lysophosphatidate acyltransferase activity 21 days after flowering and initiated triacylglycerol synthesis 28 days after flowering, while Northern blot analysis showed that mRNA for the lyosphosphatidate acyltransferase accumulated 14 days after flowering.
These observations indicate that the lysophosphatidate acyltransferase in developing seeds of the cauliflower line is responsible for synthesis of triacylglycerol molecular species that were esterifed with saturated acyl residues at the sn-2 position.
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