Which HIV protein is involved in integration of viral DNA into host genome?

AIIMS CRE 2025

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS CRE 2025

Explanation

Integrase is the specific HIV enzyme responsible for inserting the viral DNA, created by reverse transcriptase, into the host cell's DNA.
This process, known as integration, is a critical and permanent step in the HIV life cycle, converting the host cell into a provirus.
The question asks for the protein involved in 'integration', making Integrase the correct answer by definition of its function.
Once integrated, the viral DNA can remain latent or be actively used by the host cell's machinery to produce new viral particles.

Option A: Protease acts at the final stage of the HIV life cycle, not during integration. Its role is to cleave large, non-functional viral polyproteins into smaller, active proteins, which is essential for the maturation of new virus particles after they have budded from the host cell.
Option C: Reverse transcriptase acts before integration. Its function is to convert the virus's RNA genome into DNA. This DNA is the substrate that integrase then inserts into the host genome.
Option D: gp120 is a surface glycoprotein, not an enzyme involved in the internal replication process. Its function is to bind to the CD4 receptor on the surface of host immune cells, initiating the process of viral entry.

Visual 1: Diagram - A clear diagram of the HIV life cycle, highlighting the key steps: 1. Binding & Fusion (gp120), 2. Reverse Transcription (Reverse Transcriptase), 3. Integration (Integrase), 4. Replication, 5. Assembly, and 6. Budding & Maturation (Protease). Each step should point to the relevant enzyme/protein.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain HIV replication cycle and key viral proteins as background academic context rather than a clinical decision trigger.
Understanding the function of these proteins is fundamental to HIV treatment, as they are the primary targets for antiretroviral therapy (ART).
Major classes of ART drugs are named after the enzymes they inhibit: Integrase Strand Transfer Inhibitors (INSTIs, e.g., Raltegravir, Dolutegravir), Protease Inhibitors (PIs, e.g., Ritonavir, Atazanavir), and Reverse Transcriptase Inhibitors (NRTIs/NNRTIs, e.g., Tenofovir, Efavirenz).
What if the question asked which protein is targeted by drugs like Raltegravir or Dolutegravir? The answer would be Integrase, as these are potent integrase inhibitors that block the integration step.

How to Approach the Question

First, identify the core concept of the question, which is the function of a specific HIV protein.
Scan the question for keywords. Here, 'integration', 'viral DNA', and 'host genome' are the critical clues.
The term 'integration' directly points to the enzyme named for this function: Integrase.
Recall the major steps of the HIV life cycle in sequence: Attachment (gp120) -> Reverse Transcription (Reverse Transcriptase) -> Integration (Integrase) -> Maturation (Protease).
Confirm your choice by mentally reviewing the roles of the other options (distractors) to ensure they are involved in different steps of the viral life cycle.

Concept Tested & Keywords

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