The mechanism of a trans-acting mutation, dgkR1, which causes a 7-fold elevation of diacylglycerol kinase activity in membranes was investigated by direct measurement of diacylglycerol kinase polypeptide was high performance liquid chromatography and by construction of fusions of the dgkA promoter to β-galactosidase and galactokinase. The dgkR1 mutation was demonstrated to act by increasing the transcription of the structural gene for diacylglycerol kinase, dgkA. Additionally, sn-glycerol-3-phosphate acyltransferase activities were shown to be decreased 30-50% in membranes from dkgR1 mutant strains. Increased diacylglycerol levels occurred when cells were grown on low osmolarity media. This did not affect dkgA expression. In a dgkR+ background, enhanced expression of sn-1,2-diacylglycerol kinase activity in cells containing a high copy number plasmid bearing dgkA decreased sn-1,2-diacylglycerol levels. However, overproduction of diacylglycerol kinase in a dgkR1 genetic background did not affect diacylglycerol levels, suggesting that the dgkR1 mutation affects diacylglycerol metabolism by mechanisms additional to enhancement of dgkA transcription.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Biological Chemistry|
|State||Published - Dec 1 1986|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology