title: Altered sensitivity of an R5X4 HIV-1 strain 89.6 to coreceptor inhibitors by a single amino acid substitution in the V3 region of gp120.
abstract: The replication of several R5X4 strains is blocked by single CXCR4 inhibitors such as AMD3100 or T140 although the target cells express both CXCR4 and CCR5 in vitro. To identify which region(s) of the Env are involved in the increased sensitivity to CXCR4 inhibitors, we isolated a T140-escape mutant using R5X4 HIV-1 strain 89.6. An isolated mutant harbored a single amino acid substitution in the V3 region of the Env (arginine 308 to serine R308S). Luciferase-reporter HIV-1 pseudotyped with the mutant Env showed that the substitution conferred total resistance to CXCR4 antagonists but increased sensitivity to a CCR5 antagonist TAK-779 in the infection of the cells expressing both CCR5 and CXCR4. Analyses using the cells expressing a single coreceptor showed that the mutant Env predominantly and efficiently utilized CCR5 rather than CXCR4 while retaining R5X4 phenotype. These results indicated that the sensitivities of the R5X4 strain to coreceptor inhibitors were altered by a single amino acid substitution in the V3 region of gp120.
authors.affiliation: Department of Medical Virology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan. ymaeda@kumamoto-u.ac.jp
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Maeda
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yusa
authors.forename: Shinji
authors.initials: S
authors.lastname: Harada
mesh_terms: D000577:Amides / Q000494:pharmacology; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000187:drug effects*; D000998:Antiviral Agents / Q000494:pharmacology; D065100:CCR5 Receptor Antagonists; D002460:Cell Line; D024882:Drug Resistance, Viral; D017930:Genes, Reporter; D005822:Genetic Vectors; D015699:HIV Envelope Protein gp120 / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics*; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009842:Oligopeptides / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D019713:Receptors, CCR5 / Q000235:genetics; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors*
chemical_list: D000577:Amides; D000998:Antiviral Agents; D065100:CCR5 Receptor Antagonists; D015699:HIV Envelope Protein gp120; D009842:Oligopeptides; D000644:Quaternary Ammonium Compounds; D019713:Receptors, CCR5; D019718:Receptors, CXCR4; C119369:TAK 779; C116977:T140 peptide