Efficient replication and gene expression of human immunodeficiency virus-1 (HIV-1) involves specific interaction of the viral protein Tat, with its trans-activation responsive element (TAR) which forms a highly stable stem-loop structure. We have earlier shown that a 15-mer polyamide nucleotide analog (PNA) targeted to the loop and bulge region of TAR blocks Tat-mediated transactivation of the HIV-1 LTR both in vitro and in cell culture (Mayhood et al., Biochemistry 39 (2000) 11532). In this communication, we have designed four anti-TAR PNAs of different length such that they either complement the entire loop and bulge region (PNATAR-16 and PNATAR-15) or are short of few sequences in the loop (PNATAR-13) or in both the loop and bulge (PNATAR-12), and examined their functional efficacy in vitro as well as in HIV-1 infected cell cultures. All four anti-TAR PNAs showed strong affinity for TAR RNA, while their ability to block in vitro reverse transcription was influenced by their length. In marked contrast to PNATAR-12 and PNATAR-13, the two longer PNATARs were able to efficiently sequester the targeted site on TAR RNA, thereby substantially inhibiting Tat-mediated transactivation of the HIV-1 LTR. Further, a substantial inhibition of virus production was noted with all the four anti-TAR PNA, with PNATAR-16 exhibiting a dramatic reduction of HIV-1 production by nearly 99%. These results point to PNATAR-16 as a potential anti-HIV agent.
All Science Journal Classification (ASJC) codes
- HIV-1 replication
- Polyamide nucleotide analog
- Reverse transcription
- Tat-mediated transactivation
- Trans-activation response region