FIG. 5.

Requirement for cullin 5 in degradation of DNA ligase IV. A549 cells were preinfected with E1-deficient, replication-defective adenovirus vectors expressing FLAG-tagged wild-type (WT) cullin 5 or a dominant-negative carboxy-terminal truncation cullin 5 mutant (NTD) or an empty-vector control. Sixteen hours postinfection, cells were superinfected with Ad5. Fifty-six hours after superinfection, lysates were prepared and analyzed by immunoblotting for expression of cullin 5 (via the FLAG tag), endogenous DNA ligase IV, E4 34k, and cellular actin (loading control). The positions of the full-length and NTD cullin 5 proteins are marked at the left of the bottom panel. The Mock/Mock lysate was not analyzed for either E4 34k or the FLAG tag.