Document 0819 DOCN M9620819 TI Block of HIV-1 infection by a combination of antisense tat RNA and TAR decoys: a strategy for control of HIV-1. DT 9602 AU Chang HK; Gendelman R; Lisziewicz J; Gallo RC; Ensoli B; Laboratory of Tumor Cell Biology, National Cancer Institute,; National Institutes of Health, Bethesda, MD 20892, USA. SO Gene Ther. 1994 May;1(3):208-16. Unique Identifier : AIDSLINE MED/96050942 AB The tat gene product (Tat) of HIV-1 is an early regulatory protein necessary for viral gene expression and replication. Tat may also play a role as an extracellular protein in both HIV-1 replication and AIDS-associated disorders such as Kaposi's sarcoma. Thus, Tat represents a good target for gene therapy against AIDS. Here we show that when vectors expressing antisense tat RNA are transiently transfected into CD4+ cells, they block about 70% of HIV-1 replication and inhibit the rescue of Tat-defective HIV-1 proviruses by inhibition of Tat protein expression and consequent lack of transcriptional activation of the HIV-promoter. However, antisense tat vectors cannot block the activity of extracellular Tat protein. Another tat inhibitory construct (poly-Tat-activation response; TAR) previously suggested to inhibit HIV-1 transactivation by sequestering the Tat protein, inhibited the activity of extracellular Tat, but like antisense tat RNA did not completely block viral gene expression and replication. These results suggested that one mode of inhibition is not sufficient to block Tat function. However, when the antisense tat and the poly-TAR constructs were combined HIV-1 gene expression was completely blocked (94-98%), suggesting that a combination of inhibitory genes blocking Tat by sequential steps may be a better approach for AIDS gene therapy. DE Acquired Immunodeficiency Syndrome/THERAPY Antisense Elements (Genetics)/GENETICS Base Sequence Cell Line CD4-Positive T-Lymphocytes/VIROLOGY Gene Expression/DRUG EFFECTS Gene Therapy *Genes, tat Hela Cells Human HIV Infections/*PREVENTION & CONTROL/VIROLOGY *HIV-1/DRUG EFFECTS/GENETICS/PHYSIOLOGY Molecular Sequence Data Plasmids/GENETICS RNA, Antisense/GENETICS/*PHARMACOLOGY Transfection Virus Replication/DRUG EFFECTS/GENETICS JOURNAL ARTICLE SOURCE: National Library of Medicine. NOTICE: This material may be protected by Copyright Law (Title 17, U.S.Code).