Fig. 4.

The role of Ena1 and Nha1 in growth under diverse pH conditions. (A) Northern blot analysis for monitoring ENA1 or NHA1 expression in response to different pH conditions. Total RNA was isolated from WT strain H99 grown in different pH conditions as described in Materials and Methods. The relative expression level of ENA1 or NHA1 was quantitatively measured with phosphoimager analysis by normalization with ACT1 expression levels. (B and C) Cells (WT, hog1, ena1, ena1 nha1, nha1 mutants and nha1/NHA1 complemented strain) were spotted on YPD agar medium that was adjusted to acidic (pH 4.5) or alkaline pH (pH 8.5) YPD and contained indicated concentration of KCl or NaCl. (D) Expression levels of NHA1 were monitored under different pH condition (pH 7, pH 4.5, and pH 8.5) in the presence of 1.5 M KCl. The relative expression level of NHA1 was quantitatively measured as described above in (A).