Specificity and mechanism of error-prone replication by human immunodeficiency virus-1 reverse transcriptase

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT) is crucial for viral replication.
• Understanding the fidelity of HIV-1 RT during DNA synthesis is vital for antiviral drug development.

Purpose of the Study:

• To investigate the error-proneness of HIV-1 RT during in vitro DNA synthesis.
• To analyze the types and distribution of mutations generated by HIV-1 RT.
• To explore the mechanisms underlying these errors, such as template-primer slippage.

Main Methods:

• In vitro DNA synthesis using recombinant or viral HIV-1 RT on M13mp2 DNA.
• Sequence analysis of resulting DNA mutants to identify errors.
• Processivity analysis of HIV-1 RT on the M13mp2 DNA template.

Main Results:

• HIV-1 RT exhibits a high error rate in vitro, potentially causing approximately five mutations per genome per replication round in vivo.
• Mutations are nonrandomly distributed, with hot spots for base substitutions and one-base frameshifts.
• Template-primer slippage appears to be a major mechanism initiating frameshift and base substitution errors.
• Specific termination sites were observed during processivity analysis, correlating with frameshift mutational hot spots.

Conclusions:

• HIV-1 RT's error-prone nature and specific mutation patterns can significantly impact viral evolution.
• Template-primer slippage and dissociation-reinitiation phases are critical in generating mutations.
• These findings have implications for understanding HIV-1 genetic diversity and developing targeted therapies.