Entecavir and tenofovir suppress hepatitis B virus replication by targeting which property of the viral genome?
- A The circular partially double-stranded DNA is repaired to covalently closed circular DNA by a virion-encoded reverse transcriptase ✓
- B The fully double-stranded linear DNA integrates into the host chromosome before replication
- C The single-stranded circular RNA is replicated by a host RNA polymerase
- D The segmented double-stranded RNA requires a virion cap-snatching enzyme
Correct answer: A. The circular partially double-stranded DNA is repaired to covalently closed circular DNA by a virion-encoded reverse transcriptase
Explanation
HBV carries a relaxed circular partially double-stranded DNA genome. Inside the hepatocyte nucleus it is completed to covalently closed circular DNA (cccDNA), which serves as the template for transcription. The virion polymerase is a reverse transcriptase that copies pregenomic RNA back into DNA, and nucleos(t)ide analogues such as entecavir and tenofovir inhibit this step. Distractor B fails because integrated HBV DNA is dead-end and does not support replication.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.