Drug resistance profiles of recombinant reverse transcriptases from human immunodeficiency virus type 1 subtypes A/E, B, and C.
We have expressed purified recombinant reverse transcriptase (RT) from clinical isolates of human immunodeficiency virus subtypes B, C, and A/E in Escherichia coli. The drug sensitivities of these RTs were then determined for both nucleoside RT inhibitors (NRTIs) and nonnucleoside RT inhibitors (NNRTIs) in cell-free RT assays. Although A/E and C viruses contained numerous polymorphisms relative to subtype B (i.e., naturally occurring variations unrelated to drug resistance), the wild-type enzymes prepared from these or subtype A/E clinical isolates displayed <2-fold differences in drug sensitivities with regard to the active triphosphate active forms of NRTIs, as compared with RT expressed from BH-10 recombinant virus. Recombinant RTs from clinical isolates of subtypes B, C, and A/E that contained multiple resistance-associated mutations displayed expected variations in levels of resistance to the intracellular active forms of 3TC, ddI, ddC, and PMPA, that is, 3TCTP, ddATP, ddCTP, and PMPApp, respectively. Subtype A/E and C RT enzymes contained only minor NNRTI polymorphisms that distinguished them from wild-type subtype B enzymes and wild-type RTs from these various subtypes showed only 1- to 4-fold variability in IC(50) values for each of nevirapine (NVP), delavirdine (DLV), efavirenz (EFV), and calanolide A. In contrast, RT enzymes from subtype B and C viruses harboring specific NNRTI mutations were highly resistant to all four tested NNRTIs. Subtype C variants containing the novel V106M resistance codon showed cross-resistance to all approved NNRTIs in cell-free RT assays.
Quan
Yudong
Y
McGill University AIDS Centre, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, H3T 1E2, Canada.
Brenner
Bluma G
BG
Marlink
Richard G
RG
Essex
Max
M
Kurimura
Takashi
T
Wainberg
Mark A
MA
D001483:Base Sequence; D024882:Drug Resistance, Viral; D005838:Genotype; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors*; D015497:HIV-1 / Q000145:classification* / Q000187:drug effects*; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*
D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase