UL44 interacts with human Ubc9 in yeast two-hybrid assays.

1UL44, UL54, and Ubc9 proteins were fused to the C-terminus of LexA protein and/or of GAL4 activation domain (GAD). Fusion proteins were then assayed for interaction by qualitative β-galactosidase (β-gal) filter assays and by quantitative β-gal liquid assays.
2β-gal expression was scored as follows +, strong blue color detected within 2 h of incubation; ±, blue color detected after more than 2 h of incubation; −, no signal detected after 16–24 h of incubation. Values within parentheses represent β-gal units ± standard deviation (SD) of 3–4 yeast colonies from at least three independent transformations.