Figure 3.

OLE RNA expression is induced by short-chain alcohols. (a) Relative expression levels of OLE and a reporter gene (gfpuv mRNA fused to the OLE RNA promoter) after 3 h with either no stress (–) or near-lethal levels of methanol [M, 9% (v/v)], ethanol [E, 6% (v/v)], or isopropanol [I, 4% (v/v)]. Cells were incubated for 3 h with a short-chain alcohol or no added alcohol as indicated prior to RNA extraction. RNA levels were determined via Northern blot analysis (see inset for a representative blot; all dots were formed by loading an equal amount of total RNA; top row was probed for OLE RNA and bottom row was probed for 16S RNA) and normalized to the value measured at time zero for the given alcohol and reporter. Error bars represent the standard error of the mean of three independent experiments. (b) Representative time course of OLE RNA induction by ethanol (see Supplementary Figure S5 for a representative northern blot). Cells were treated either without or with 5% (v/v) ethanol for the indicated time. Transcript levels were determined as described in (a) and the lines approximate the data trends obtained either in the absence or presence of ethanol.