The transcriptional co-activator proteins p300 and CBP stimulate adenovirus E1A conserved region 1 transactivation independent of a direct interaction.

p300 and CBP are two related transcriptional co-activator proteins required by many cellular transcription factors for activity. The adenovirus E1A protein binds p300 and CBP through its amino-terminus and conserved region (CR) 1. Fusing CR1 to a heterologous DNA-binding domain creates a potent transcriptional activator, suggesting that CR1 might activate transcription by recruiting p300/CBP to the promoter. We show that both p300 and CBP enhances CR1-dependent transactivation. However, this enhancement occurs independently of a direct interaction with E1A and does not correlate with the CR1 activator function.