Inhibition of HIV-1 replication in vitro and in human infected cells by modified antisense oligonucleotides targeting the tRNA(Lys3) /RNA initiation complex

The untranslated 5' leader region of the human immunodeficiency virus type 1 (HIV-1) RNA plays an essential role in retroviral replication. It is the first retrotranscribed RNA region, primed from a cellular tRNA(Lys3) partia lly annealed to the HIV-1 primer binding site (PBS). The structural and fun ctional features of the HIV-1 reverse transcription initiation complex have been thoroughly studied. In this work, we used chemically modified antisen se oligonucleotides (AS-ODN) as competitors of the natural tRNA(Lys3) prime r for the PBS region. Modified 2'-O-methyl AS-ODN were able to inhibit in v itro HIV-1 reverse transcription and displace the tRNA(Lys3) previously ann ealed to the PBS. The destabilization of the initiation complex by 2'-O-met hyl ODN was a sequence-specific process. We further demonstrated the import ance of an anchor region contiguous to the PBS in the annealing of the anti sense molecule, allowing the displacement of tRNA(Lys3). The 20-mer 2'-O-me thyl molecules were also able to inhibit viral replication in HIV-1-human i nfected cells, either by blocking cDNA synthesis during the early phase or by interfering with the annealing of the tRNA(Lys3) primer to the PBS durin g the late phase of the viral cycle. Thus, the highly conserved retroviral initiation complex was shown to be a promising target when using the antise nse strategy.