2007 Fiscal Year Final Research Report Summary
System biologic approach to lipid traffic and conversion in eukaryotic microorganisms and its application
| Project/Area Number |
17208008
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied microbiology
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| Research Institution | The university of Tokyo |
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Principal Investigator |
OHTA Akinori The university of Tokyo, Graduate School of Agricultural and Life Sciences, Professor (30125885)
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| Co-Investigator(Kenkyū-buntansha) |
HORIUCHI Hiroyuki The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor (00209280)
FUKUDA Ryouichi The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate Professor (50323481)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Saccharomyces cerevisiae / Yarrowia lipolytica / phospholipid uptake / acyl chain remodeling / phosphatidylethanolamine / phosphatidylcholine / cytochrome P450ALK / alkane hydroxylation |
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| Research Abstract |
This project was comprised of two parts : One is the analysis on the uptake and acyl-chain remodeling of phospholipids with short fatty acid residues by yeast Saccharomyces cerevisiae. In previous research, we showed that phosphatidylethanolamine (PE) and phosphatidylcholine (PC) with 8-to 12-carbon-fatty acid residues were incorporated and utilized by S. cerevisiae mutants defective in the synthesis of these phospholipids. In this project, we proved that these soluble phospholipids were. transported into the cells and their acyl chains are actually replaced with those of normal length by tracing the change of stable isotope-labeled PE and PC with decanoic acids. Thus the remodeling of phospholipids in their fatty acid residues is a common property of eukaryotic cells.
The other part is the finding of a negative transcription factor, Yas3, for alkane-induced gene expression in Yarrowia lipolytica. In our previous research, we reported two cooperative positive regulatory factors, Yaslp and Yas2p, with bHLH motifs. We found that Yas3p changed its intracellular localization. When the lipolytica cells were grown in the presence of alkane, Yas3p-GFP was found in ER, but in the absence of alkane, it was found in nucleus, where it likely represses the function of Yas1p and Yas2p by binding to Yas2p. We also found Yas3p specifically bound to phosphatidic acid and PA phosphatase mutation increased expression of the alkane-inducible ALK1 gene, suggesting the change in the amount of PA is important in the function of Yas3p. We also investigated expression of 12 ALK genes by RT-PCR and found not all ALK genes are responsive to alkane.
The latter part of our project resulted in a discovery of a very strong inducible promoter in Y. lipolytica and a mutant strain that is suitable for the expression of cytochrome P450 genes.
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Research Products
(20 results)
