Roles of viral oncoproteins
| Oncoprotein | Function | Source |
|---|---|---|
| E1 | - Highly conserved across HPV strains.- Indispensable for initiating and regulating HPV replication. | [52] |
| E2 | - Multifaceted role in viral replication and transcription.- Influences other critical processes.- Can either activate or repress viral gene expression. | [53] |
| E4 | - Translated as an E1^E4 fusion protein.- Leucine cluster motif is crucial for keratin binding.- C-terminus facilitates self-association, forming structures reminiscent of amyloid fibers.- Plays a pivotal role in regulating the cytokeratin network to aid viral release and dissemination. | [54] |
| E5 | - Significant in HPV-mediated carcinogenesis.- Supports cellular hyperproliferation and cancer progression in both high-risk (HR-HPV) and low-risk (low-riskHPV) forms.- Influences E6 and E7 activities. | [55, 56] |
| E6 | - Relatively large (18 kDa).- Contains two zinc finger domains.- Primarily found in the nucleus.- Orchestrates the transformation of normal cells into malignant ones, significantly contributing to cervical carcinogenesis. | [57, 58] |
| E7 | - Approximately 100 amino acids long.- Comprises three conserved regions (CR1, CR2, and CR3).- A key player in cervical carcinogenesis through interactions with various host factors. | [59, 60] |