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. 2004 Aug 17;2(8):e235. doi: 10.1371/journal.pbio.0020235

Figure 4. HAC1 Promoter Regulation Is Required to Survive Stress.

Figure 4

(A) Determination of Hac1p levels during either ER stress alone or during both ER stress and temperature shift. WT cells were either grown at 30 °C and treated with DTT (lanes 1–4) or grown at 23 °C and simultaneously shifted to 37 °C and treated with DTT (lanes 5–8). Protein lysates were prepared, and protein levels were analyzed by Western blot analysis. The relative Hac1p/Pgk1p ratio is normalized to the DTT-treated sample (lane 4).

(B) Characterization of HAC1 expression in strain used to approximate basal HAC1 expression. Cells expressing HAC1 from the endogenous promoter (lanes 1–4) or the ADH1 promoter (lanes 5–8) were grown at 30 °C in synthetic medium supplemented with inositol and shifted to synthetic medium lacking inositol simultaneous with the addition of tunicamycin.

(C) Reduced viability of strains unable to express HAC1 at elevated levels. The strains described in (B) were plated in serial dilutions (left to right) on synthetic medium lacking inositol (“−ino”) and synthetic medium lacking inositol and containing tunicamycin (“−ino +TM”).