FIG 5.

Genetic analysis of the Zta basic/DNA binding domain in mediating Zta ubiquitination. (A) Schematic diagram of Zta basic leucine zipper-like (bZIP) domain mutants. (B and C) EBV-negative AdAH cells were transfected with or without 5 μg of a ubiquitin (His6-Ub) expression vector and 5 μg of the indicated Zta, Zta mutant, or control expression plasmids. Cells were lysed under denaturing conditions and extracts were purified over nickel-NTA beads. The purified material was assayed by Western blot analysis employing an anti-Zta antibody. Expression levels of Zta and its mutants were determined by Western blot analysis of whole-cell lysates. The images were spliced to unify the Western blot format.