PHOSPHOROTHIOATE OLIGONUCLEOTIDES DERIVED FROM HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-1) PRIMER TRNA(LYS3) ARE STRONG INHIBITORS OF HIV-1REVERSE-TRANSCRIPTASE AND ARREST VIRAL REPLICATION IN INFECTED-CELLS

Retroviral reverse transcriptase (RT) is involved in the selection of a specific tRNA primer which initiates proviral DNA minus-strand synth esis. Studies of the interactions between human immunodeficiency virus type I (HIV-1) RT and primer tRNA(Lys3) have shown that the dihydrour idine (diHU), anticodon, and pseudouridine regions of tRNA are highly protected in the RT-tRNA complex The CCA 3' end of tRNA is also in clo se contact with the enzyme during the cDNA initiation step. Using synt hetic oligoribonucleotides corresponding to the anticodon and diHU reg ions, we have previously shown a low but significant inhibition of HIV -1 RT activity (37). We extend this observation and show that primer t RNA-derived oligodeoxynucleotides (ODNs) carrying a phosphorothioate ( PS) modification are strong inhibitors of HIV-1 RT. The affinity of PS -ODNs for the enzyme was monitored by gel mobility shift electrophores is. Experiments with HIV-l-infected human cells (MT-2 cells) were perf ormed with the latter ODNs. A PS-ODN corresponding to the 3' end of tR NA(Lys3) (acceptor stem [AS]) was able to inhibit HIV-1 replication. N o effect of the other modified ODNs was observed in infected cells. Th e analysis of HIV-1 RNase H activity in a cell-free system strongly su ggests that the inhibitory effect of the PS-AS may be mediated via bot h a sense and an antisense mechanism.