FIG. 1.

Viruses used in cell cycle experiments. AdRb contains an HA-tagged full-length human cDNA under the control of a constitutive CMV promoter inserted into the E1A region of Ad. AdΔRb contains an HA-tagged mutant mouse Rb cDNA under the control of the EF1 alpha promoter inserted into the E1A/E1B region of Ad. Asterisks indicate mutations in nine phosphorylation sites in the Rb cDNA: Thr-246, Ser-601, Ser-605, Ser-780, Ser-786, Ser-787, and Ser-800 were changed to Ala; Thr-350 was changed to Arg; and Ser-804 was changed to Ala. These mutations render the protein unphosphorylatable. Adβ-gal, used as a control in these experiments, contains the β-gal cDNA under the control of the CMV promoter inserted into the E1A/E1B region of Ad.