Growth-rate regulation of the Bacillus subtilis accBC operon encoding subunits of acetyl-CoA carboxylase, the first enzyme of fatty acid synthesis

Abstract.

Acetyl-CoA carboxylase catalyses the synthesis of malonyl-CoA, the first intermediate in fatty acid (hence phospholipid) synthesis. The accBC operon from Bacillus subtilis codes for two subunits of acetyl-CoA carboxylase, biotin carboxyl-carrier and biotin carboxylase. In this work, the 5′-end of the accBC mRNA was determined by primer-extension, and transcriptional fusion analysis of the accBC promoter was carried out under a variety of growth conditions. A direct correlation between the levels of transcription of the accBC genes and the rate of cellular growth is reported. Consistent results were also obtained in nutritional upshift and downshift experiments.