FIG 1.

PTP1 and PTP2 are Hog1-dependent stress-inducible genes. Northern blot analyses were performed using the total RNA isolated from each strain [WT (strain H99) and hog1 (YSB64), atf1 (YSB676), HOG1^T171A+Y173A (YSB253), and HOG1^K49S+K50N (YSB308) mutant strains], which was grown to mid-logarithmic phase at 30°C in YPD medium and exposed to 2.5 mM H₂O₂ (A, C, and D) or 1 M NaCl (B). Each membrane was hybridized with PTP1- or PTP2-specific probes, washed, and developed. The same membrane was stripped and reprobed with the ACT1-specific probe. (A and B) The relative PTP1 or PTP2 expression levels were quantitatively measured through phosphorimager analysis after normalization with ACT1 expression levels. Each value at indicated time points represents expression levels relative to the levels at the zero time point of the wild-type strain. (C and D) Each membrane was hybridized with the PTP1-specific probe, washed, and developed. The same membrane was stripped and reprobed with the PTP2-specific probe. Ethidium bromide staining results of rRNA were used as loading controls.