Table 1. UL44 interacts with human Ubc9 in yeast two-hybrid assays.
| Hybrid1 | ||
| DNA-binding domain fusion | Activation domain fusion | β-gal expression (Units ± S.D.)2 |
| LexA-UL44 | / | −(<1) |
| LexA-UL44 | GAD | −(<1) |
| / | GAD-UL54 | −(<1) |
| LexA | GAD-UL54 | ±(1043±213) |
| LexA-UL44 | GAD-UL54 | +(8244±245) |
| / | GAD-UL44 | −(<1) |
| LexA | GAD-UL44 | −(<1) |
| LexA-UL44 | GAD-UL44 | +(7643±397) |
| LexA-Ubc9 | / | −(<1) |
| LexA-Ubc9 | GAD | −(<1) |
| LexA-Ubc9 | GAD-UL44 | +(6915±343) |
| / | GAD-Ubc9 | −(<1) |
| LexA | GAD-Ubc9 | −(<1) |
| LexA-UL44 | GAD-Ubc9 | +(7012±214) |
1
UL44, 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.
2
β-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.