FIGURE 2.

Increased silencing in the absence of inositol and/or at 37 °C is dependent on Sir2p and Slt2p. Wild type, sir2Δ, and slt2Δ strains carrying the TELV_R::URA3 construct were grown on I⁺ medium until mid-logarithmic phase, diluted back to A_{600 nm} = 0.2 in I⁺ and I⁻ media at 30 or 37 °C, and allowed to grow until an A_{600 nm} of 1.0. Gene expression levels were examined by RT-PCR and calculated using the comparative C_T method (ΔΔC_T) as described under “Experimental Procedures.” The changes in URA3 expression levels are log₂ ratios of the level of expression measured by RT-PCR in a specific strain, under the given growth condition, relative to URA3 expression in the control culture. The asterisk refers to the mRNA derived from the wild type control grown in I⁺NA⁺ medium at 30 °C and served as a reference (unit = 1) for measuring relative URA3 expression levels. A indicates the strains grown at 30 °C. B indicates the strains grown at 37 °C. Data represent the mean ± S.E. of three independent experiments, n = 3.