Fig. 1.

Overexpression of Dpb11 but not Ddc1 suppresses the HU sensitivity of ddc2-top. (A) YDM003, a Δddc2 Δsml1 yeast strain carrying pDM158 (a URA3 CEN plasmid expressing ddc2-top under its endogenous promoter) was transformed with galactose-inducible Dpb11 or Ddc1 high-copy (2μ) or low-copy (cen) expression vectors or an empty vector control. Cells were grown to mid-log phase and serial dilutions were spotted onto galactose plates with the indicated concentration of hydroxyurea (HU) and incubated at 30 °C. (B and C) The HU sensitivity of Δddc2 Δsml1 or ddc2-top yeast strains containing galactose-inducible Dpb11, Dpb11–1, or an empty TRP1 plasmid as indicated were compared on galactose plates as in A.