Figure 4.

Inhibition of p73-mediated cell killing by E4orf6. (A, B) Saos-2 cells and derivatives of Saos-2 cells expressing E4orf6 protein (SaosE4#5 and SaosE4#11) were cotransfected with a plasmid expressing the puromycin-resistance marker plus a plasmid expressing p73α, p73β, or the expression plasmid with no insert. Puromycin-resistant colonies were counted 14 days later. Photographs of colonies (A) and the percentage of cells giving rise to colonies (B) are presented. (C) Western blot assay using antibody to E4orf6 protein (αE4) demonstrating expression of the E4orf6 protein (E4) in derivatives of Saos-2 cells that contain the E4orf6 gene.