Figure 2.

Wild-type pVHL interacts with hCUL-2 only in the presence of elongins B and C in yeast. hCUL-1 and hCUL-2 cDNAs were expressed in pAS2–1 and VHL cDNAs in pACT2. Plasmids were transformed into different CG1945 yeast strains expressing control sequence, elongin B, elongin C, or elongin BC together. β-Gal activity was measured in permeabilized yeast by using o-nitrophenyl-β-d-galactoside as the substrate. Absorbance values are relative to β-gal activity in yeast expressing the control plasmids pVA3–1 and pTD1–1 (p53 fragment and SV40T antigen). Expression of proteins was verified by Western blot analysis (data not shown).