Oligonucleotide inhibition of the interaction of HIV-1 Tat protein with the trans-activation responsive region (TAR) of HIV RNA

The interaction of HIV-1 Tat protein with its recognition sequence, the tra ns-activation responsive region TAR is a potential target for drug discover y against HIV infection. We show by use of an in vitro competition filter b inding interference assay that synthetic oligodeoxyribonucleotides compleme ntary to the HIV-1 TAR RNA apical stem-loop and bulge region inhibit the bi nding of Tat protein or a Tat peptide (residues 37-72) better than two smal l molecules that have been shown to bind TAR RNA, Hoechst 33258 and neomyci n B. The inhibition is not sensitive to length between 13 and 16 residues o r precise positioning but shorter oligonucleotides are less effective. Enha nced inhibition was obtained for 16-mer 2'-O-methyl oligoribonucleotide but not for C5-propyne pyrimidine-substituted oligonucleotides, Control non-an tisense oligonucleotides were occasionally also effective in filter binding interference but only the complementary antisense 2'-O-methyl oligoribonuc leotide was effective in gel mobility shift assays in direct TAR binding or in interference with Tat peptide binding to the TAR stem-loop. This is the first demonstration of effective inhibition of the Tat-TAR interaction by nuclease-stabilized oligonucleotide analogues. (C) 1999 Elsevier Science B. V. All rights reserved.