The oncogenic action of the HPV E7 protein in cervical carcinogenesis is best described as:
- A Binding to retinoblastoma protein and releasing E2F transcription factor ✓
- B Binding to p53 and promoting its ubiquitin-mediated degradation
- C Inhibiting telomerase reverse transcriptase expression
- D Activating caspase-mediated apoptosis of infected keratinocytes
Correct answer: A. Binding to retinoblastoma protein and releasing E2F transcription factor
Explanation
E7 binds the hypophosphorylated retinoblastoma protein, disrupting the Rb-E2F complex and freeing E2F to drive entry into S phase, which produces unscheduled proliferation. Degradation of p53 is the function of E6, which also activates telomerase rather than inhibiting it. E7 also inactivates p21 and p27 cell cycle inhibitors, but the classic examined action is Rb binding. Apoptosis induction contradicts the biology of E7.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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