Two Coselected Distal Mutations in HIV-1 Reverse Transcriptase (RT) Alter Susceptibility to Nonnucleoside RT...

Area of Science:

• Virology
• Molecular Biology
• Drug Resistance

Background:

• Antiretroviral therapy (ART) is effective against HIV-1 but can be undermined by drug-resistant variants.
• Novel nonnucleoside reverse transcriptase inhibitors (NNRTIs) are being developed to combat resistance.
• Understanding resistance mechanisms is crucial for developing effective HIV-1 treatments.

Purpose of the Study:

• To investigate the impact of two novel mutations, G112D and M230I, in HIV-1 reverse transcriptase (RT) on susceptibility to a new NNRTI.
• To analyze the combined and individual effects of these mutations on HIV-1 RT activity and drug response.
• To explore the potential cross-sensitivity of these mutations to nucleoside reverse transcriptase inhibitors (NRTIs).

Main Methods:

• Selection of mutations G112D and M230I in HIV-1 RT using a novel NNRTI.
• Biochemical assays to assess RT activity and drug susceptibility.
• Virological assays to evaluate the impact of mutations on viral replication and drug response.

Main Results:

• The M230I mutation reduced susceptibility to NNRTIs, while G112D alone did not.
• The G112D/M230I double mutant exhibited lower NNRTI susceptibility than M230I alone.
• Both mutations altered the incorporation of nucleoside analogs by RT, suggesting interaction via the nucleic acid substrate.

Conclusions:

• The novel mutations G112D and M230I in HIV-1 RT confer resistance to a new NNRTI.
• These mutations may interact through the nucleic acid substrate within the polymerase active site.
• The identified mutations lead to increased sensitivity to certain NRTIs, such as AZT, offering potential therapeutic avenues.