title: Higher fidelity of RNA-dependent DNA mispair extension by M184V drug-resistant than wild-type reverse transcriptase of human immunodeficiency virus type 1.
abstract: Reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) has low fidelity compared with RTs of other retroviruses and cellular DNA polymerases. We and others have previously found that the fidelity of DNA-dependent DNA polymerization (DDDP) of M184V-mutated HIV-1 RT is significantly higher than that of wild-type RT. Viruses containing the M184V substitution are highly resistant to (-)-2'-dideoxy-3'-thiacytidine (3TC) in vitro and in patients treated with 3TC monotherapy. It was of interest to determine the fidelity of RNA-dependent DNA polymerization (RDDP) of M184V RT compared with wild-type because this step occurs first in reverse transcription; errors made during this step may be copied in subsequent polymerization steps. Using an in vitro mispaired primer extension assay, M184V-mutated RT exhibited 3-49-fold decreased frequency of mispair extension compared with wild-type RT. Fidelity differences between M184V and wild-type RT were most marked in extension of A:G (49-fold) and A:C (16-fold) mispairs, with only a marginal (3-fold) decrease in the extension of A:A mispairs. RT containing a methionine to isoleucine (M184I) mutation showed only slight increases in RDDP fidelity compared with wild-type, ranging from 1.5- to 6-fold increases. Of the three RTs tested, wild-type RT was the most error-prone, with mispair extension frequencies ranging from 6.674 x 10(-1) to 7.454 x10(-2).
authors.affiliation: Department of Microbiology and Immunology, McGill University, Montreal, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Hsu
authors.forename: P
authors.initials: P
authors.lastname: Inouye
authors.forename: L
authors.initials: L
authors.lastname: Rezende
authors.forename: N
authors.initials: N
authors.lastname: Richard
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: V R
authors.initials: VR
authors.lastname: Prasad
authors.forename: M A
authors.initials: MA
authors.lastname: Wainberg
mesh_terms: D004247:DNA / Q000378:metabolism*; D004351:Drug Resistance; D004352:Drug Resistance, Microbial; D054303:HIV Reverse Transcriptase / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D009154:Mutation; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism; D012313:RNA
chemical_list: D009692:Nucleic Acid Heteroduplexes; C034477:RNA primers; D012313:RNA; D004247:DNA; D054303:HIV Reverse Transcriptase