Inhibition of HIV-1 gene expression by novel DNA enzymes targeted to cleave HIV-1 TAR RNA: potential effectiveness against all HIV-1 isolates.
Nucleic acid-based antiviral approaches have been tried against multiple HIV-1 genes with the purpose of down-regulating its replication. A unique stem-loop structure called TAR is present at the 5'-end of all HIV-1 transcripts; Tat and other cellular proteins bind to TAR and thus govern transcription. Therefore, HIV-1 TAR is an attractive target against which various antiviral approaches could be tried. We screened several DNA enzymes (Dz's) containing the 10-23 catalytic motif and a single Dz containing the 8-17 catalytic motif against the HIV-1 TAR RNA. Dz's directed against the predicted single-stranded bulge regions showed sequence-specific cleavage activities. One of the two Dz's, namely Dz-475, showed moderate cleavage activity in complete absence of Mg(2+). Addition of unrelated sequences at the 5'-end of the HIV-1 TAR RNA rendered it susceptible to four additional Dz-mediated cleavages. Both Dz's (470 and 475) showed significant intracellular reduction of HIV-1 gene expression. Dz-475-treated cells showed significant protection against T-tropic and macrophage-tropic HIV-1 challenge. Dz-475-transfected T-lymphocytes, human PBMCs, or chronically infected cell lines showed marked viral resistance. Unique features of this antiviral strategy with respect to HIV-1 gene inhibition are discussed.
Chakraborti
Samitabh
S
Laboratory of Virology, National Institute of Immunology, JNU Campus, Aruna Asaf Ali Marg, 110067, New Delhi, India.
Banerjea
Akhil C
AC
D019380:Anti-HIV Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001483:Base Sequence; D021881:DNA, Catalytic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D015658:HIV Infections / Q000517:prevention & control; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000201:enzymology / Q000235:genetics*; D006367:HeLa Cells / Q000201:enzymology / Q000821:virology; D006801:Humans; D008264:Macrophages / Q000201:enzymology / Q000821:virology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013601:T-Lymphocytes / Q000201:enzymology / Q000821:virology; D014162:Transfection
D019380:Anti-HIV Agents; D021881:DNA, Catalytic; D004277:DNA, Single-Stranded; D012367:RNA, Viral; C402582:RNA-cleaving DNA 10-23; C407482:RNA-cleaving DNA 8-17