Human immunodeficiency virus type 1 pol gene mutations which cause decreased susceptibility to 2',3'-dideoxycytidine.
To investigate whether human immunodeficiency virus type 1 pol gene mutations are selected during prolonged 2',3'-dideoxycytidine (ddC) therapy, we used the polymerase chain reaction to amplify a portion of the reverse transcriptase segment of the pol gene from the peripheral blood mononuclear cell DNA of a patient with AIDS before and after an 80-week course of ddC therapy. The consensus sequence from the second sample contained a unique double mutation (ACT to GAT) in the codon for reverse transcriptase amino acid 69, causing substitution of aspartic acid (Asp) for the wild-type threonine (Thr). A mutation (ACA to ATA) also occurred in the codon for position 165, causing substitution of isoleucine (Ile) for Thr. The GAT (Asp) codon was introduced into the pol gene of a molecular clone of human immunodeficiency virus via site-directed mutagenesis. Following transfection, mutant and wild-type viruses were tested for susceptibility to ddC by a plaque reduction assay. The mutant virus was fivefold less susceptible to ddC than the wild type; cross-resistance to 3'-azido-3'-deoxythymidine or 2'3'-dideoxyinosine was not found. The Ile-165 mutation did not confer additional ddC resistance. The Asp-69 substitution may have contributed to the generation of resistant virus in this patient.
Fitzgibbon
J E
JE
Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry, New Jersey-Robert Wood Johnson Medical School, Piscataway 08854.
Howell
R M
RM
Haberzettl
C A
CA
Sperber
S J
SJ
Gocke
D J
DJ
Dubin
D T
DT
D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D004352:Drug Resistance, Microbial; D015751:Genes, pol / Q000187:drug effects*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D006824:Hybridization, Genetic; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D016047:Zalcitabine / Q000627:therapeutic use*
D016047:Zalcitabine