FIG. 6.

DNA replication activity of large T-Ag mutant proteins. (A) Transient DNA replication activities of the indicated wild-type or mutant T-Ag proteins in C33A cells. DNA replication activities were measured by determining the ratio of firefly (Fluc-ori plasmid) to Renilla (Rluc control plasmid) luciferase activity as described in Materials and Methods. Replication activities are reported as a percentage of the Fluc/Rluc ratio obtained with the largest amount of wild-type T-Ag expression vector. Cells transfected with vector only (No T-Ag) were used as a negative control. (B) Expression of T-Ag proteins. Western blot analysis of total protein extracts prepared from transfected C33A cells expressing the wild-type or the indicated T-Ag mutant proteins. α, anti.