Figure 2.

Phenotype of cip1Δ and cip2Δ mutant strains. (A) Strains carrying Cip1 or Cip2 tagged at their genomic loci with CFP or GFP, respectively, were used to determine the localization of each protein. Cip1 and Cip2 show cytoplasmic localization in cells growing in minimal medium (EMM), without (top) or during treatment with 1 mM H₂O₂ for 15 min (bottom). (B) cip1Δ, cip2Δ and cip1Δcip2Δ strains were grown to mid-log phase at 30°C and analyzed under the microscope. (C) Left, spot assays of wild-type and mutant strains. Fourfold serial dilutions were plated on EMM plates (CONTROL) or EMM plates supplemented with 0.6 mM H₂O₂. No thiamine was added to the media to induce overexpression of Cip2. Pictures were taken after incubating the plates for 5 d at 30°C. Right, morphology of Cip2-overexpressing cells. Wild-type cells containing the endogenous copy of cip2⁺ under the control of the nmt1 promoter were grown in liquid EMM media in the absence (–B1) or presence (+B1) of thiamine. Pictures were taken after growing cells to mid-log phase for 21 h in the indicated media at 30°C.