Adenoviral E1A: everlasting tool, versatile applications, continuous contributions and new hypotheses.

Adenoviral E1A is an indispensable protein for virus-host interaction. To provide a suitable environment for viral replication, E1A physically interacts with multiple cellular proteins to reprogram gene expression and other processes of the host cells. Proteins targeted by E1A include the pRb family of pocket proteins, p300/CBP, cyclin/Cdk, the carboxyl terminal binding protein (CtBP), transcriptional regulator YY1, and the recently identified RACK1 and SWI/SNF complex. Reprogramming activity of E1A and the host cell response to this reprogramming lead to transformation, growth arrest or apoptosis. Based on the ability of E1A to override the fundamental controls of host cells, E1A has been being utilized to make continuous contributions not only to a better understanding of the molecular mechanisms underlying the regulation of transcription, cell division, apoptosis and tumorigenesis but also to new therapeutics such as gene therapy.