Detection of HIV-1 proviral hypermutation and evaluation of its association with disease outcomes
V. Correa Vieira1, A. de Oliveira Afonso2, J. Silveira1, E. Stankiewicz Machado2,3, M. Alves Soares2, A.M. Barral de Martinez1
1Universidade Federal do Rio Grande, Rio Grande, Brazil, 2Universidade Federal do Rio de Janeiro, Departamento de Genética, Rio de Janeiro, Brazil, 3Universidade Federal do Rio de Janeiro, Hospital Universitário Clementino Fraga Filho, Rio de Janeiro, Brazil
Background: APOBEC3G and APOBEC3F can restrict the HIV-1 pathogenesis inducing extensive G-to-A hypermutation into viral cDNA. Considering that hypermutation represents a potential antiretroviral strategy, it is important to determine its role in the clinical course of HIV-1 infection.Thus, the aim of this study was to verify the presence of G-to-A mutations introduced by APOBEC3 proteins in viral sequences and determinate its association with HIV-1 disease progression outcomes.
Methods: Blood samples were collected from 12 HIV-1 positive long-term nonprogressors (LNTP) and 6 rapid progressors. Genomic DNA and plasma RNA were extracted and the region of protease was amplified. PCR amplicons from proviral sequences were cloned, at least ten clones from each sample were obtained. After sequencing they were compared to sequences derived from plasma virus and to population-especific consensus using Hypermut 2.0 (available at www.lanl.hiv.org) to detect G-to-A hypermutation.
Results: In this study 179 proviral sequences were analyzed. The median of G-to-A mutations in the sequences derived from LNTPs were 3.3 times higher than in rapid progressors (p=0.05), and the median of mutations occurred in the GG and GA dinucleotide contexts were 2.36 times higher (p=0.15). Two drastically hipermutated sequences were identified (p>0.05). They were obtained from a LNTP individual, thus no rapid progressors presented drastically hipermutated sequences. Besides this, no statically significant difference was found (p=0.46).
Conclusions: Despite G-to-A mutation were more frequently found in LNTP individuals, the presence of sequences drastically hypermutated was not significantly associated with LNTP status. Thus hypermutation may be contributing to slow progression in these patients, however it is not likely to determine LNTP status by itself.
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