Identification of a key target sequence to block human immunodeficiency virus type 1 replication within the gag-pol transframe domain

Although the full sequence of the human immunodeficiency virus type 1 (HIV- 1) genome has been known for more than a decade, effective genetic antivira ls have Set to be developed. Here we show that, of 22 regions examined, one highly conserved sequence (ACTCTTTGGCAACGA) near the 3' end of the HIV-1 g ag-pol transframe region, encoding viral protease residues 4 to 8 and a C-t erminal Vpr-binding motif of p6(Gag) protein in two different reading frame s, can be successfully targeted by an antisense peptide nucleic acid oligom er named PNA(PR2). A disrupted translation of gag-pol mRNA induced at the P NA(PR2)-annealing site resulted in a decreased synthesis of pr160(Gag-Pol) polyprotein, hence the viral protease, a predominant expression of pr55(Gag ) devoid of a fully functional p6(Gag) protein, and the excessive intracell ular cleavage of Gag precursor proteins, hindering the processes of virion assembly. Treatment with PNA(PR2) abolished virion production by up to 99% in chronically HIV-l-infected H9 cells and in peripheral blood mononuclear cells infected with clinical HIV-1 isolates with the multidrug-resistant ph enotype. This particular segment of the gag-pol transframe gene appears to offer a distinctive advantage over other regions in invading viral structur al genes and restraining HIV-1 replication in infected cells and may potent ially be exploited as a novel antiviral genetic target.