Zidovudine (AZT) monotherapy selects for the A360V mutation in the connection domain of HIV-1 reverse transcriptase.

TitleZidovudine (AZT) monotherapy selects for the A360V mutation in the connection domain of HIV-1 reverse transcriptase.
Publication TypeJournal Article
Year of Publication2012
AuthorsBrehm JH, Scott Y, Koontz DL, Perry S, Hammer S, Katzenstein D, Mellors JW, Sluis-Cremer N
Corporate AuthorsAIDS Clinical Trials Group Study 175 Protocol Team
JournalPLoS One
Volume7
Issue2
Paginatione31558
Date Published2012
ISSN1932-6203
KeywordsAdenosine Triphosphate, Amino Acid Substitution, Anti-HIV Agents, Drug Resistance, Viral, HIV Infections, HIV Reverse Transcriptase, HIV-1, Humans, Mutagenesis, Site-Directed, Mutant Proteins, Mutation, Phenotype, Protein Structure, Tertiary, Recombination, Genetic, Ribonuclease H, RNA, Viral, Zidovudine
Abstract

BACKGROUND: We previously demonstrated in vitro that zidovudine (AZT) selects for A371V in the connection domain and Q509L in ribonuclease H (RNase H) domain of HIV-1 reverse transcriptase (RT) which, together with the thymidine analog mutations D67N, K70R and T215F, confer greater than 100-fold AZT resistance. The goal of the current study was to determine whether AZT monotherapy in HIV-1 infected patients also selects the A371V, Q509L or other mutations in the C-terminal domains of HIV-1 RT.

METHODOLOGY/PRINCIPAL FINDINGS: Full-length RT sequences in plasma obtained pre- and post-therapy were compared in 23 participants who received AZT monotherapy from the AIDS Clinical Trials Group study 175. Five of the 23 participants reached a primary study endpoint. Mutations significantly associated with AZT monotherapy included K70R (p = 0.003) and T215Y (p = 0.013) in the polymerase domain of HIV-1 RT, and A360V (p = 0.041) in the connection domain of HIV-1 RT. HIV-1 drug susceptibility assays demonstrated that A360V, either alone or in combination with thymidine analog mutations, decreased AZT susceptibility in recombinant viruses containing participant-derived full-length RT sequences or site-directed mutant RT. Biochemical studies revealed that A360V enhances the AZT-monophosphate excision activity of purified RT by significantly decreasing the frequency of secondary RNase H cleavage events that reduce the RNA/DNA duplex length and promote template/primer dissociation.

CONCLUSIONS: The A360V mutation in the connection domain of RT was selected in HIV-infected individuals that received AZT monotherapy and contributed to AZT resistance.

DOI10.1371/journal.pone.0031558
Alternate JournalPLoS ONE
PubMed ID22363673
PubMed Central IDPMC3283647
Grant List1U01AI068636-01 / AI / NIAID NIH HHS / United States
204VC009 / / PHS HHS / United States
25XS119 / / PHS HHS / United States
5T32AI065380-04 / AI / NIAID NIH HHS / United States
AI069470 / AI / NIAID NIH HHS / United States
R01 AI081571 / AI / NIAID NIH HHS / United States
R01 AI081571 / AI / NIAID NIH HHS / United States
T32-5TL1RR024155-04 / RR / NCRR NIH HHS / United States
TL1 RR024155 / RR / NCRR NIH HHS / United States
UM1 AI069423 / AI / NIAID NIH HHS / United States
UM1 AI069477 / AI / NIAID NIH HHS / United States