Regulation of yeast phospholipid biosynthetic gene expression in response to inositol involves two superimposed mechanisms

The modulation of the expression of the genes that prepare phospholipid in the presence of inositol in yeasts probably involves the release of the cognate activator gene, INO2, and the inhibition of the negative-acting gene, OPI1. The biosynthesis of phospholipids is affected by the regulation of transcription of INO2 and OPI1. However, transcription of the INO2 gene which is under the control of the GALI promoter gene, is unaffected by inositol but is influenced by galactose.