HIV-1 integrase inhibitors (e.g., raltegravir) block which specific step of the HIV replication cycle?

• A Strand transfer of HIV DNA into the host chromosome after 3' processing ✓
• B Reverse transcription of HIV RNA into double-stranded DNA
• C Maturation of immature virions by HIV protease
• D Fusion of HIV envelope with the CD4+/CCR5 cell membrane

Explanation

Integrase strand transfer inhibitors (INSTIs) block the strand transfer step: after HIV reverse transcriptase produces viral dsDNA, integrase performs 3' processing (removing two nucleotides from each 3' end) and then strand transfer (inserting processed viral DNA ends into host chromosomal DNA); INSTIs chelate the two Mg2+ ions in the catalytic site blocking strand transfer, not 3' processing. Reverse transcriptase inhibitors (NRTIs, NNRTIs) block DNA synthesis. HIV protease inhibitors block gag-pol polyprotein cleavage during maturation. Fusion inhibitors (enfuvirtide) and CCR5 antagonists (maraviroc) block entry.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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