45. Cervical cancer-causing Papilloma virus produces two oncoproteins E6 and E7 which are responsible for interfering with cell cycle regulation by
    (1) inactivating Rb and p53, respectively
    (2) modulating p53 and pRb, respectively
    (3) binding to cyclin D1 and CDK4
    (4)activating expression of p21

The cervical cancer-causing Papilloma virus produces two oncoproteins, E6 and E7, which interfere with cell cycle regulation by:

(1) inactivating Rb and p53, respectively

Explanation

• The HPV E6 protein targets the tumor suppressor p53 for ubiquitin-mediated proteasomal degradation, reducing its ability to induce apoptosis and cell cycle arrest in response to DNA damage.

• The HPV E7 protein binds and inactivates the retinoblastoma protein (Rb), which normally inhibits the E2F transcription factor, thereby releasing E2F to activate genes required for S-phase entry and cell proliferation.

• This combined inactivation of p53 and Rb disrupts cell cycle checkpoints and promotes uncontrolled cellular proliferation, a critical step in cervical carcinogenesis.

• E6 and E7 oncoproteins are essential for HPV-mediated immortalization and transformation of infected cells.​