Table 1.
Summary of HPV gene functions.
| Function in viral lifecycle | Activities | Target factor |
|---|---|---|
| E1 | ||
| Replication of viral genome | DNA-binding activity, helicase activity, ATPase | RPA, topoisomerase, polymerase alpha-primase |
| E2 | ||
| Transcription of viral genes | ||
| Replication of viral genome Maintenance of viral genome |
Transactivation/transrepression, DNA-binding activity, DNA segregation in mitotic cell | Brd4, ChlR1 |
| E6 | ||
| Reactivation of cellular replication mechanisms | ||
| Proliferation, immortalization, inhibition of apoptosis Maintenance of viral genome |
Interaction with various cellular proteins | p53, ADA3, p300/CBP, E6AP, SP1, c-Myc, NFX1-91, TERT, FAK, FADD, Caspase 8, BAX, BAK, IRF3, PDZ domain proteins |
| E7 | ||
| Reactivation of cellular replication mechanisms | ||
| Proliferation, genomic instability, inhibition of apoptosis Maintenance of viral genome |
Interaction with various cellular proteins | RB, p107, p130, HDAC, E2F6, p21, p27, CDK/cyclin, ATM, ATR, gamma-tubulin |
| E4 | ||
| Unknown | ||
| Destruction of keratin network, induction of G2M arrest of cell cycle | Cytokeratin 8/18 | |
| E5 | ||
| Possibly involved in proliferation and/or | ||
| inhibition of apoptosis | Affection of cellular signaling pathway | EGFR, PDGFR, V-ATPase, MHC1, TRAIL receptor, FAS receptor |
| L1 | ||
| Major capsid protein | ||
| L2 | ||
| Minor capsid protein | ||