Figure 3.

CHX20 fused to GFP is functionally active. KTA40-2 yeast (ena1-4Δ nha1Δ nhx1Δ kha1Δ) was transformed with empty pDR196 vector, CHX20, or CHX20-GFP. AXT3 (ena1-4Δ nha1Δ nhx1Δ) was transformed with empty vector and served as a native ScKHA1 positive control. Cells were serially diluted 10-fold and spotted on YNB plates. A, CHX20 did not confer tolerance to hygromycin. Five microliters of yeast was spotted on YNB medium at pH 5.5 with or without hygromycin B (150 μg/mL) and incubated for 4 d. B, CHX20 fused to GFP conferred tolerance to the KTA40-2 strain at basic pH. Yeast was spotted on medium adjusted to pH 7.5 with Arg base and incubated for 2 d.