FIG. 3.

Analysis of tpp1⁺ expression in S. pombe. (A) Increase in the level of expression of tpp1⁺ mRNA following heat, osmotic, or oxidative stress in control strain CHP429. (B) Evidence for regulation of the expression of tpp1⁺ by the wis1-sty1 (equivalent to phh1 and spc1) mitogen-activated protein kinase pathway during osmotic stress using strain TK107 (Δphh1::ura4⁺). (C) Analysis of Δpka1 strain CHP433 indicates that Pka1 activity negatively modulates the basal level and the expression of tpp1⁺ during heat and osmotic shock. (D) Expression of tpp1⁺ in a Δpka1 Δsck1 strain suggests that derepression of tpp1⁺ in the absence of Pka1 is dependent on the cellular level of Sck1 activity.