Reverse transcriptase gene analysis of HIV-1 mutants cultured in the presence of AZT

Abstract

HIV-1 strains were isolated from four patients treated with AZT for more than 6 months and from three patients untreated with AZT. Isolates from patients treated with AZT have been cultured by passage of virus in cell culture in the presence of 1 microM AZT. However the isolates from patients untreated with AZT could not be cultured in the presence of AZT. The RT gene of HIV-1 isolates which had been cultured in the presence of AZT were amplified by PCR and cloned to M13 vector. Four amino acid mutations in RT gene (Asp67, Lys70, Thr215, Lys219) associated with resistance to AZT were analysed. All of the 22 clones obtained from the isolates in the presence of 1 microM AZT had mutations at codon 215(Thr-->Tyr or Phe). Some of the 22 clones also had other mutations at codon 67 (Asp-->Ser), codon 70 (Lys-->Arg) and codon 219 (Lys-->Glu or Gln). Four amino acid residues in RT gene of the isolates which had been cultured in the presence of AZT were compared to that of the isolates cultured in the absence of AZT. The clones of the isolates obtained from the patients (04 or 05) had mutations at only codon 215 Thr-->Tyr) in both the presence and the absence of AZT. All of the clones of the isolates obtained from the patients (06 or 07) had mutations at codon 215 and some of them had other mutations.(ABSTRACT TRUNCATED AT 250 WORDS)