Emergence of human immunodeficiency virus type 1 variants with resistance to multiple dideoxynucleosides in patients receiving therapy with dideoxynucleosides

Proc Natl Acad Sci U S A. 1995 Mar 14;92(6):2398-402. doi: 10.1073/pnas.92.6.2398.


A set of mutations [Ala-62-->Val(A62V), V75I, F77L, F116Y, and Q151M] in the polymerase domain of reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) confers on the virus a reduced sensitivity to multiple antiretroviral dideoxynucleosides and has been seen in HIV-1 variants isolated from patients receiving combination chemotherapy with 3'-azido-3'-deoxythymidine (AZT) plus 2',3'-dideoxycytidine (ddC) or 2',3'-dideoxyinosine (ddI). The IC50 values of AZT, ddC, ddI, 2',3'-dideoxyguanosine, and 2',3'-didehydro-3'-deoxythymidine against an infectious clone constructed to include the five mutations were significantly higher than those of a wild-type infectious clone. The K1 value for AZT 5'-triphosphate determined for the virus-associated RT from a posttherapy strain was 35-fold higher than that of RT from a pretherapy strain. Detailed analysis of HIV-1 strains isolated at various times during therapy showed that the Q151M mutation developed first in vivo, at the time when the viremia level suddenly increased, followed by the F116Y and F77L mutations. All five mutations ultimately developed, and the viremia level rose even further. Analyses based on the three-dimensional structure of HIV-1 RT suggest that the positions where at least several of the five mutations occur are located in close proximity to the proposed dNTP-binding site of RT and the first nucleotide position of the single-stranded template.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acquired Immunodeficiency Syndrome / drug therapy*
  • Amino Acid Sequence
  • Base Sequence
  • Cloning, Molecular
  • DNA Primers / chemistry
  • DNA Primers / metabolism
  • Dideoxynucleosides / pharmacology*
  • Dideoxynucleosides / therapeutic use*
  • Dose-Response Relationship, Drug
  • Drug Resistance, Multiple*
  • Genes, pol
  • Genetic Variation*
  • Genotype
  • HIV Reverse Transcriptase
  • HIV-1 / drug effects
  • HIV-1 / genetics*
  • HIV-1 / isolation & purification
  • Humans
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Point Mutation*
  • Polymerase Chain Reaction
  • Protein Structure, Secondary
  • RNA-Directed DNA Polymerase / biosynthesis
  • RNA-Directed DNA Polymerase / chemistry
  • RNA-Directed DNA Polymerase / genetics*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Templates, Genetic
  • Transfection


  • DNA Primers
  • Dideoxynucleosides
  • Recombinant Proteins
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase