FIG. 7.

Increased dosage of Siz1 E3 ligase restores ubc9-10 cell resistance to Top1 poisons. (A) ubc9-10 top1Δ cells, cotransformed with YEpSIZ1 and YCpSctopT₇₂₂A or vector controls, were diluted, spotted onto selective medium, and incubated at 26°C or 36°C. (B) Extracts of wild-type UBC9 or mutant ubc9-10 strains, transformed with YEpSIZ1 or vector control, were immunoblotted with anti-yUbc9 (α yUbc9), α Smt3, or α tubulin antibodies. (C) ubc9-10 cells, cotransformed with YEpSIZ1 and YEpyUBC9 or YEpGPDhUBC9, were spotted onto selective medium plus HU and incubated at 26°C or 36°C.