Expression of the Saccharomyces cerevisiae inositol-1-phosphate synthase (INO1) gene is regulated by factors that affect phospholipid synthesis.

摘要: Abstract The INO1 gene of Saccharomyces cerevisiae encodes the regulated enzyme inositol-1-phosphate synthase, which catalyzes first committed step in synthesis inositol-containing phospholipids. The expression this was analyzed under conditions known to regulate phospholipid synthesis. RNA blot hybridization with a genomic clone for detected two species 1.8 and 0.6 kb. abundance 1.8-kb greatly decreased when cells were grown presence precursor inositol, as activity synthase. Complementation analysis showed that transcript encoded product. level repressed 12-fold medium containing it 33-fold inositol choline together. present at very low mutations (ino2 ino4) regulatory genes unlinked result auxotrophy. constitutively overproduced mutation (opi1) causes constitutive synthase results excretion inositol. also examined (cho2) affecting phosphatidylcholine. In contrast what observed wild-type cells, growth cho2 did not significant decrease abundance. Inositol together required repression these providing evidence link between inositol- choline-containing lipids. 0.6-kb affected, although lesser degree, by many same factors influence expression.