Selection and characterization of a mutant of feline immunodeficiency virus resistant to 2',3'-dideoxycytidine.
We have selected and plaque purified a mutant of feline immunodeficiency virus (FIV) that is resistant to 2',3'-dideoxycytidine (ddC). This mutant was selected in cultured cells in the continuous presence of 25 microM ddC. The mutant, designated DCR-5c, was fourfold resistant to ddC, threefold resistant to 2',3'-dideoxyinosine, and more than fourfold resistant to phosphonoformic acid. DCR-5c displayed little or no resistance to (-)-beta-2',3'-dideoxy-3'-thiacytidine, 3'-azido-3'-deoxythymidine, or 9-(2-phosphonylmethoxyethyl) adenine. Reverse transcriptase purified from DCR-5c was less susceptible to inhibition by ddCTP, phosphonoformic acid, ddATP, or azido-dTTP than the wild-type FIV reverse transcriptase. Sequence analysis of DCR-5c revealed a single base change (G to C at nucleotide 2342) in the reverse transcriptase-encoding region of FIV. This mutation results in substitution of His for Asp at codon 3 of FIV reverse transcriptase. The role of this mutation in ddC resistance was confirmed by site-directed mutagenesis.
Medlin
H K
HK
Division of Biological Sciences, University of Montana, Missoula 59812, USA.
Zhu
Y Q
YQ
Remington
K M
KM
Phillips
T R
TR
North
T W
TW
D000595:Amino Acid Sequence; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002415:Cats; D002460:Cell Line; D016049:Didanosine / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D016089:Immunodeficiency Virus, Feline / Q000187:drug effects* / Q000235:genetics*; D008969:Molecular Sequence Data; D012194:RNA-Directed DNA Polymerase / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D016047:Zalcitabine / Q000494:pharmacology*; D015215:Zidovudine / Q000494:pharmacology
D000998:Antiviral Agents; D018894:Reverse Transcriptase Inhibitors; D015215:Zidovudine; D016047:Zalcitabine; D012194:RNA-Directed DNA Polymerase; D016049:Didanosine