FIGURE 2:

The nuclear periphery inhibits GAL1 mRNA expression. (A) Changes in GAL1 mRNA expression in yeast with disrupted peripheral localization of the GAL locus. Wild-type, ada2Δ, or nup1Δ mutant cells were grown in YP plus 2% glucose (YPD) to mid-log phase. GAL1 mRNA expression was induced by galactose. GAL1 mRNA levels were measured at the indicated times by quantitative RT-PCR. GAL1 mRNA levels were normalized to levels of a control gene, TFC1, and the fold change in expression was calculated relative to the baseline expression at the zero time point for each strain. Error bars represent SEM for three independent experiments. (B) GAL1 mRNA turnover in galactose in wild-type and ada2Δ mutant cells. rpb1-1 and rpb1-1 ada2Δ cells were grown in YPGal medium at 25°C and then shifted to 37°C to inactivate transcription. GAL1 mRNA levels were measured at the indicated time points by qRT-PCR and plotted as a function of time following the shift to the nonpermissive temperature. GAL1 mRNA levels were normalized to the RNA pol III transcript SCR1 and expressed relative to the level of transcript at the zero time point, defined as 1.0. (C) Gal1 protein levels increase in ada2∆ cells. Cells were grown in raffinose medium and induced with 2% galactose for the indicated time, and Gal1-GFP protein levels were analyzed using flow cell cytometry. Mean GFP intensity of the population (in arbitrary units) is plotted as a function of time in galactose. Error bars represent SEM for three independent experiments.