title: Selection and characterization of human immunodeficiency virus type 1 variants resistant to the (+) and (-) enantiomers of 2'-deoxy-3'-oxa-4'-thio-5-fluorocytidine.
abstract: Human immunodeficiency virus (HIV) type 1 (HIV-1) variants were selected for resistance to the (+) and (-) enantiomers of a novel nucleoside analogue, 2'-deoxy-3'-oxa-4'-thio-5-fluorocytidine (dOTFC), by use of the infectious molecular clone HIV HXB2D and the human T-cell line MT-4. The dOTFC-resistant variants that were selected were 10-fold less sensitive than wild-type virus, and cloning and sequencing of the complete reverse transcriptase (RT)-coding region identified the mutation M184V. Studies with mutated recombinant HXB2D virus confirmed the importance of the M184V mutation in conferring resistance to (-)dOTFC in MT-4 cells, although no difference in sensitivity was observed in primary cells. The M184V substitution also displayed decreased susceptibility to (+)dOTFC. Selection with (+)dOTFC also produced variants which were 10-fold more resistant than the wild type, and a novel mutation, D67G, was identified following cloning and sequencing of the RT genes. The D67G mutation was introduced into HXB2D by site-directed mutagenesis, and the data obtained confirmed the importance of this mutation in conferring resistance to both (+)dOTFC and (-)dOTFC. Mutated recombinant molecular clone HXB2D-D67G was further selected with (+)dOTFC, and three of six clones sequenced contained both the D67G and M184V mutations, while the other three of the six clones contained only the D67G mutation. Clinical isolates of HIV-1 which are (-) 2'-deoxy-3'-thiacytidine-resistant also displayed resistance to both (+)dOTFC and (-)dOTFC.
authors.affiliation: McGill University AIDS Centre, Lady Davis Institute-Jewish General Hospital, Montréal, Québec, Canada H3T 1E2.
authors.forename: N
authors.initials: N
authors.lastname: Richard
authors.forename: H
authors.initials: H
authors.lastname: Salomon
authors.forename: R
authors.initials: R
authors.lastname: Rando
authors.forename: T
authors.initials: T
authors.lastname: Mansour
authors.forename: T L
authors.initials: TL
authors.lastname: Bowlin
authors.forename: M A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D019380:Anti-HIV Agents / Q000494:pharmacology*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D013329:Structure-Activity Relationship; D013872:Thionucleosides / Q000494:pharmacology*
chemical_list: C120719:2'-deoxy-3'-oxa-thiocytidine; D019380:Anti-HIV Agents; D013872:Thionucleosides; D003841:Deoxycytidine; C081758:2'-deoxy-5-fluoro-3'-thiacytidine