title: Co-receptor usage and HIV-1 intra-clade C polymorphisms in the protease and reverse transcriptase genes of HIV-1 isolates from Ethiopia and Botswana.
abstract: Knowledge of baseline amino acid substitutions arising at certain critical positions in the HIV-1 non-clade-B protease (PR) and reverse transcriptase (RT) enzymes may yield important information with regard to anticipation of responses to antiretroviral treatment and development of drug resistance. We have compared RT and PR sequences within HIV-1 clade C strains isolated from 14 treatment-naive patients originating from Ethiopia and Botswana with those of PR and RT consensus subtype B RT and PR sequences. Variations in the frequency of natural polymorphisms were observed in clade C isolates at drug-resistance sites. Intra-clade C divergence among mutations within PR was statistically significant while that within RT was not. Only a M361 substitution in PR was shared among almost all isolates from Ethiopia and Botswana. Analysis of the co-receptor usage of clade C isolates from Ethiopia and Botswana supports the known preferential usage of the CCR5 co-receptor by HIV-1 clade C strains. No Ethiopian or Botswanian isolates exclusively used the CXCR4 co-receptor, which is consistent with most data obtained with HIV-1 clade B isolates.
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada.
authors.forename: Hugues
authors.initials: H
authors.lastname: Loemba
authors.forename: Bluma
authors.initials: B
authors.lastname: Brenner
authors.forename: Michael A
authors.initials: MA
authors.lastname: Parniak
authors.forename: Shlomo
authors.initials: S
authors.lastname: Ma'ayan
authors.forename: Bonnie
authors.initials: B
authors.lastname: Spira
authors.forename: Daniela
authors.initials: D
authors.lastname: Moisi
authors.forename: Maureen
authors.initials: M
authors.lastname: Oliveira
authors.forename: Mervi
authors.initials: M
authors.lastname: Detorio
authors.forename: Max
authors.initials: M
authors.lastname: Essex
authors.forename: Mark A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D019943:Amino Acid Substitution; D019380:Anti-HIV Agents / Q000494:pharmacology; D001483:Base Sequence; D001902:Botswana; D004351:Drug Resistance / Q000235:genetics; D005002:Ethiopia; D016333:HIV Protease / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012194:RNA-Directed DNA Polymerase / Q000235:genetics*; D019713:Receptors, CCR5 / Q000378:metabolism*
chemical_list: D019380:Anti-HIV Agents; D019713:Receptors, CCR5; D012194:RNA-Directed DNA Polymerase; D016333:HIV Protease