FIG. 3.

E4orf1 restricts viral late protein synthesis in adenovirus-infected cells. (A) Duplicate cultures of asynchronously dividing HeLa cells were infected with the indicated viruses and pulse-labeled with ³⁵S-labeled amino acids at 36 hpi. Labeled proteins were separated by electrophoresis and visualized by phosphorescence imaging. The late structural proteins hexon, penton, and fiber are indicated. The status of the relevant viral gene is indicated below each lane. (B) Asynchronously dividing HeLa cells were infected with the indicated viruses and pulse-labeled for 1 h with ³⁵S-labeled amino acids at 24, 36, and 48 hpi. Radioactivity incorporated into the hexon protein was quantified by phosphorescence imaging. This value was normalized to the amount of radioactivity incorporated into hexon in dl1520 virus-infected cells at 36 hpi. The values shown are the mean of 9 to 23 independent infections with the standard error of the mean indicated. The status of the relevant viral gene is indicated below each virus. (C) The relative rate of late protein synthesis directed by representative viruses at late times after infection is schematically represented for an E4orf1 deletion mutant virus, an E1B-55K deletion mutant virus, and the wild-type virus. E4orf1 restricts viral late protein synthesis at all times of infection in the E1B-55K mutant background and at very late times in the context of a wild-type virus infection.