Mutants of feline immunodeficiency virus resistant to 2',3'-dideoxy- 2',3'-didehydrothymidine

Ya Qi Zhu, Kathryn M. Remington, Thomas W. North

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12 Scopus citations


We selected mutants of feline immunodeficiency virus (FIV) that are resistant to 2',3'-dideoxy-2',3'-didehydrothymidine (d4T). Two mutants were selected in cultured cells with a stepwise increase in d4T concentration, resulting in mutants able to replicate in 100 μM d4T. These mutants were three- to sixfold more resistant to d4T than wild-type FIV. They were also cross-resistant to 3'-azido-3'-deoxythymidine (AZT), 3'-fluoro-2',3'- dideoxythymidine, 2',3'-dideoxycytidine, 2',3'-dideoxyinosine, and 9-(2- phosphonylmethoxyethyl)adenine, and they were highly resistant to phosphonoformic acid (PFA). Plaque-purified mutants were isolated from each of the mutant populations. The mutant phenotype was stable, because both of the plaque-purified mutants remained d4T resistant even after three passages in the absence of d4T. One of the plaque-purified mutants, designated D4R- 3c, was further characterized. Compared with wild-type reverse transcriptase (RT), RT purified from D4R-3c was 3-fold resistant to inhibition by the 5'- triphosphate of d4T, 10-fold resistant to inhibition by the 5'-triphosphate of AZT, and 6-fold resistant to PFA. D4R-3c had a single point mutation in the RT-encoding region of the pol gene at position 2474, resulting in a Val to Ile mutation at codon 47 of the FIV RT. The role of this mutation in d4T resistance was confirmed by site-directed mutagenesis.

Original languageEnglish (US)
Pages (from-to)1983-1987
Number of pages5
JournalAntimicrobial Agents and Chemotherapy
Issue number9
StatePublished - Sep 1996
Externally publishedYes

ASJC Scopus subject areas

  • Pharmacology (medical)


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