FIG. 1.
Requirement of aurA for IPC synthase activity and growth in A. nidulans. (A) Autoradiogram of base stable sphingolipids labeled with [3H]inositol and separated by chromatography on a Silica Gel 60 TLC plate. Cells were pretreated with AbA for 15 min before addition of [3H]inositol. The bands for sphingolipid species, IPC, mannose-inositol-P-ceramide (MIPC), and mannose-(inositol-P)-2-ceramide [M(IP)2C] of S. cerevisiae are indicated. Note the inhibition of [3H]inositol incorporation into sphingolipids in both S. cerevisiae and A. nidulans cells by AbA and the resistance to this inhibition conferred by the mutation in aurA in A. nidulans producing the G275V change. (B) Colonies of the wt and aurAG275V mutant strains grown on MAG plates containing AbA at the concentrations indicated. The strains were spot inoculated with toothpicks and were allowed to grow for 2 days at 32°C. (C) Dependence of aurA3Δ strains on the expression of functional AURA off the alcA promoter. Shown are colonies of a wt and three aurA3Δ alcA::aurA strains grown on media containing glycerol, ethanol, or glucose as the sole carbon source.