Human adenovirus early region 1A protein (E1A)

The E1A protein is the first gene product synthesized after human adenovirus infection. It is a highly conserved, proline-rich, intrinsically disordered viral regulatory protein expressed as several isoforms (289, 243, 217, 171, and 55 amino acids). It heterogeneously interacts with many host regulatory proteins (including pRb, CBP/p300, TATA-binding protein, transcription factors), driving host cells into S phase, activating viral and cellular transcription, and modulating the cell's response to infection. The transformation capacity of E1A underlies its historic role in cancer biology and experimental gene delivery, but its lack of enzymatic or receptor activity and viral origin make it an atypical "target" in the therapeutic sense. Key molecular features include several conserved regions (CR1, CR2, CR3, CR4), each mediating distinct protein-protein interactions crucial for E1A's functions in modifying host transcription, cell cycle progression, and, in some instances, cellular transformation. E1A thus acts as a molecular hub, both activating and repressing multiple host genes and protein networks, and is studied widely as a paradigm for viral-host interaction and gene regulation. Note: E1A protein is not a standard therapeutic target and should not be grouped with classical drug targets like human receptors, enzymes, or transporters. The term "target" here refers to its importance in virology and experimental oncology, not clinical pharmacology.

Other names

Adenovirus early region 1AAd5 E1AHAdV-5 E1AAdenovirus E1A transforming proteinE1A 13S proteinE1A 12S protein

Not applicable (no approved drugs act on E1A directly; experimental interventions may involve RNA interference or gene delivery vectors)