Figure 1

Schematic diagram of ergosterol-responsive promoters for controlling the metabolic flux towards erogosterol biosynthesis pathway. Genes from the mevalonate pathway in S. cerevisiae are shown in blue; heterologous expression of ADS gene is shown in green; and genes from ergosterol biosynthesis pathway are shown in red. The ERG9 expression is put under the control of ergosterol-responsive promoter (P _ERG ) to achieve dynamic control of squalene synthase availability in response to intracellular ergosterol levels. The pathway intermediates IPP, DMAPP and FPP are defined as isopentenyl pyrophosphate, dimethylallyl pyrophosphate and farnesyl diphosphate, respectively.