Figure 6.

Opy2p is a new component of the HOG pathway. (A) Synthetically osmosensitive phenotype of opy2Δ ssk1Δ cells. Tetrad analysis of meiotic products from genetic cross between yeast strains YCW1323 (MATα ssk1Δ∷Nat^R ura3 his3 leu2 lys2) and YCW1377 (MATa opy2Δ∷Kan^R ura3 his3 leu2 met15). The spores circled are resistant to both Geneticin and nourseothricin (Kan^R and Nat^R) and are also sensitive to high osmolarity. (B) Opy2p acts upstream or at the same level of Ste11p/Ste50p. Yeast cells bearing indicated mutations were transformed with either wild-type STE11 or activated STE11^ΔEE that functions independently of Ste50p in the HOG pathway (Wu et al. 1999) to test their ability to suppress the osmosensitivity of the original strains as indicated by the ability to grow on high-osmolarity media. (SD − his) Synthetic dextrose histidine drop-out medium; (−his/gal) synthetic histidine drop-out medium with galactose as carbon source.