1995 Fiscal Year Final Research Report Summary
Studies of expression of genes related to phosphatidylcholine biosynthesis in Brassica napus.
| Project/Area Number |
06640854
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理
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| Research Institution | Okazaki National Research Institutes |
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Principal Investigator |
NISHIDA Ikuo Okazaki National Research Institute, National Institute for Basic Biology, Research associate, 基礎生物学研究所, 助手 (40189288)
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| Project Period (FY) |
1994 – 1995
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| Keywords | phosphatidylcholine / CDP-choline / CTP : phosphocholine cytidylyltransferase / Freezing tolerance / Brassica napus / Isozymes |
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| Research Abstract |
(1) CTP : phosphocholine cytidylyltransferase (EC2.7.7.15, CCT) is a rate-limiting enzyme in biosynthesis of phosphatidylcholine in plant cells. I have isolated four cDNA for the CCT from a root cDNA library of Brassica napus by complementation in a yeast cct mutant. The deduced amino-acid sequence of the B.napus enzymes resembled rat and yeast enzymes in the central domain. Although all CCT ever cloned from B.napus and other organisms were predicted to be structurally hydrophilic, the yeast cct mutant transformed with one of the B.napus cDNA clones restored the CCT activity in the microsomal fraction as well as in the soluble fraction. These results are consistent with a recent view that yeast cells contained a machinery for targeting the yeast CCT to membranes, and may indicate that the B.napus CCT was compatible with the machinery.
(2) The availability of the four B.napus cDNAs for CCT will allow future characterization of the protein in more detail. This would include potential subcellular distribution of the enzyme, physiological importance of the isozymes and its relevance to PC turnover, and the complete three-dimensional structure of the enzyme. Such studies are currently underway involving over-production of the enzyme in transgenic plants and evaluation of the correlation of the changes in PC content with freezing tolerance.
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