FIG. 4.

Pathways, enzymes, and genes for engineering S. cerevisiae isoprenoid biosynthesis. Gene names and mutations: ADH6, alcohol dehydrogenase (NADP⁺); BTS1, GGPP synthase; DPP1, DGPP phosphatase; ERG9, squalene synthase; ERG20, farnesyl-diphosphate synthase; HMG1/2, 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase; upc2-1, mutation in the transcriptional regulator of anoxic genes (Upc2p) responsible for the aerobic uptake of sterol (64); sue, unknown mutations selected for aerobic sterol uptake (342). Other abbreviations: IPP, isopentenyl diphosphate; DMAPP, dimethylallyl diphosphate; FOH, farnesol.