 TThe 243 amino acid E1A protein also known as small E1A protein, transforming E1A protein encoded by the left end of the human adenovirus Ad type 2 or 5 genome has been studied in various contexts including as a model cooperating oncoprotein, an apoptosis inducing protein, and as a therapeutic oncolytic protein. All of these properties are associated with its capacity to rapidly induce S phase in a variety of cells. E1A orchestrates most of these effects by interacting with an array of chromatin remodeling complexes, including the Rb family proteins, and the HAT proteins p300 and CBP. 