The HIV-1 Integrase Mutations Y143C/R Are an Alternative Pathway for Resistance to Raltegravir and Impact the Enzyme Functions

Sandrine Reigadas,Guerric Anies,Marie-Line Andreola,Lieven J Stuyver,Herve Fleury,Bernard Masquelier,Vincent Parissi,Christina Calmels

doi:10.1371/journal.pone.0010311

Sandrine Reigadas, Guerric Anies + Show 6 more

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https://doi.org/10.1371/journal.pone.0010311

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Abstract

Resistance to HIV-1 integrase (IN) inhibitor raltegravir (RAL), is encoded by mutations in the IN region of the pol gene. The emergence of the N155H mutation was replaced by a pattern including the Y143R/C/H mutations in three patients with anti-HIV treatment failure. Cloning analysis of the IN gene showed an independent selection of the mutations at loci 155 and 143. Characterization of the phenotypic evolution showed that the switch from N155H to Y143C/R was linked to an increase in resistance to RAL. Wild-type (WT) IN and IN with mutations Y143C or Y143R were assayed in vitro in 3′end-processing, strand transfer and concerted integration assays. Activities of mutants were moderately impaired for 3′end-processing and severely affected for strand transfer. Concerted integration assay demonstrated a decrease in mutant activities using an uncleaved substrate. With 3′end-processing assay, IC50 were 0.4 µM, 0.9 µM (FC = 2.25) and 1.2 µM (FC = 3) for WT, IN Y143C and IN Y143R, respectively. An FC of 2 was observed only for IN Y143R in the strand transfer assay. In concerted integration, integrases were less sensitive to RAL than in ST or 3′P but mutants were more resistant to RAL than WT.

Highlights

Retroviral integration, which is an essential step for viral replication, is performed by viral integrase (IN)
We reported how patients who had failed to respond to therapies under RAL-containing regimens presented the N155H mutation, which was replaced over time by the Y143C/H/R mutations [14]
Baseline characteristics and follow-up Three patients with virological failure on RAL and with selection of mutations at IN position 143 were included in the study

Summary

Introduction

Retroviral integration, which is an essential step for viral replication, is performed by viral integrase (IN). The enzyme catalyses two steps: cleavage of the two 39-end nucleotides of each LTR (39-end processing), thereby producing CpA 39hydroxyl ends; and transesterification leading to the integration of both viral ends in the cellular DNA (strand transfer reaction). As this step is crucial for viral replication, numerous studies have been conducted to design HIV-1 integrase inhibitors (INI) that block the integration of viral double-stranded DNA into the host cell’s chromosomal DNA [3]. Two classes of inhibitors, interfering either with the 39 processing of the viral DNA long terminal repeats [4,5] or with the strand transfer of viral DNA into the host genome [6], have been described

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