FIGURE 9.

Distinct from the constitutive oxidation mimetic alleles, the reversibly oxidized BiP alleles do not exhibit decreased fitness in the absence of stress. A, yeast deleted for endogenous BiP (kar2Δ) and containing the indicated plasmid-encoded BiP alleles were co-cultured to assess their relative fitness during oxidative stress. Strains were co-cultured over a period of 77 h in the presence of 1 mm diamide, and graphs show the relative proportion of each strain in the co-culture over time. Solid and open circles reflect the flipped plasmid markers for each co-culture. (See “Experimental Procedures” and Table 1 for details.) B, relative level of each co-cultured strain is plotted at 0 and 77 h post-mixing of the two strains in the presence of 1 mm diamide. The data are plotted as an average of the co-cultured strains carrying swapped plasmid markers. Error bars reflect the range in values for the two averaged co-cultures (See “Experimental Procedures” and Table 2 for details.) C, strains from A were grown in the absence of diamide. Data are represented as in A. D, strains were grown and analyzed as in B, except in the absence of diamide.