Farnesol-induced growth inhibition in Saccharomyces cerevisiae by a cell cycle mechanism

Summary: The growth of budding yeast, Saccharomyces cerevisiae, was inhibited in medium containing 25 μM farnesol (FOH). The FOH-treated cells were still viable, and were characterized by a transition from budded to unbudded phase as well as a significant loss of intracellular diacylglycerol (DAG). FOH-induced growth inhibition could be effectively prevented by the coaddition of a membrane-permeable DAG analogue which can activate yeast protein kinase C (PKC). However, yeast cell growth was not initiated upon addition of the PKC activator when the cells had been pretreated with FOH for 20 min. The failure in cell growth recovery was believed to be due to a signalling-mediated cell cycle arrest in FOH-pretreated cells. Differential display analysis demonstrated that the expression of cell cycle genes encoding DNA ligase (CDC9) and histone acetyltransferase (HAT2) was strongly repressed in FOH-treated cells. Repression of the expression of these genes was effectively cancelled when cells were grown in medium supplemented with DAG. The authors propose an interference with a phosphatidylinositol-type signalling which is involved in cell cycle progression as a cause of FOH-induced growth inhibition in yeast cells.