Inhibition of Tat-mediated transactivation and HIV replication with Tat mutant and repressor domain fusion proteins

Abstract

Strategies to inhibit the spread of HIV infection consist of moter. This fusion mutant was also examined for its a number of specific molecular approaches. Since viral capacity to block both Tat-mediated transactivation and production is dependent upon Tat-mediated transactivation HIV replication. We show that three mutants Tat⌬53, of the HIV promoter through the Tat activating region Tat⌬58 and Tat⌬53/Eng result in a transdominant pheno-(TAR), tat antisense RNA, anti-tat ribozymes, TAR decoys type inhibiting wild-type Tat-mediated transactivation, and and dominant negative Tat mutant proteins have been sugthat the inhibiting potential is increased by the presence of gested as therapeutic inhibitors. We produced and tested the entire basic domain or the fusion of a repressor several Tat mutant proteins, including a newly generated domain. However, only the transdominant mutants Tat⌬58 form Tat⌬58, for the ability to inhibit Tat-mediated transand Tat⌬53/Eng significantly inhibit HIV-1 replication after activation and HIV production. In addition, we generated a infection of transfected T cell lines. These results demonnew Tat fusion mutant between a C-terminus truncated strate the potent inhibiting activity of Tat mutants on HIV form of Tat (Tat⌬53) and the Drosophila Engrailed (Eng) replication, and suggest a synergistic effect of Tat transtranscription repressor domain to test the hypothesis that dominant mutant fusion with the Drosophila Engrailed trantranscriptional repression can be targeted to the HIV proscription repressor domain.

Targeting Tat Inhibitors in the Assembly of Human Immunodeficiency Virus Type 1 Transcription Complexes

“…In contrast, the Tat AD and full-length Tat showed little inhibition, even though the Tat AD and T-U2AF65 are expressed at comparable levels (Fig. 2B), consistent with previous reports of their weak dominant negative activity (7,12,19). U2AF65 fusions with full-length Tat and with the AD alone are equally potent, showing that TAR RNA-binding activity is dispensable for inhibition.…”

“…P-TEFb is a heterodimer of cyclin T1 (CycT1) and its associated Cdk9 catalytic subunit and is required by many, but not all, activators for CTD phosphorylation, either at the promoter or during elongation (3,18,37). In the case of HIV-1, the Tat activation domain (AD; residues 1 to 48), in the absence of its RNA-binding domain (RBD), functions as a weak dominant negative that is believed to form inactive complexes with P-TEFb (12,19,33,35). Their potential use in therapeutic strategies has been hindered, in part, by their low potency.…”

High level inhibition of HIV replication with combination RNA decoys expressed from an HIV-Tat inducible vector

“…12 Since the Tat and Rev regulatory proteins play a critical role in the HIV infectious cycle, protein-based gene therapy strategies with transdominant mutants have been developed by several laboratories. These studies demonstrate that Tat and Rev mutant proteins inhibit HIV replication in lymphoid cell lines [13][14][15][16] as well as in CD4 + primary hematopoietic cells 15,17,18 and CD34 + hematopoietic precursors. 19,20 However, such mutant proteins if expressed in in vivo gene therapy applications may elicit an immune response against themselves.…”

Inducible Expression of the ΔNGFr/F12Nef Fusion Protein as a New Tool for Anti-Human Immunodeficiency Virus Type 1 Gene Therapy

“…These include the expression of either HIV-1 trans-dominant proteins (i.e., Rev, Tat) (Liu et al, 1994;Fox et al, 1995;Plavec et al, 1997;Rossi et al, 1997;Fraiser et al, 1998;Hamm et al, 1999;Mautino et al, 2001), HIV-1 antisense sequences (Lavigne and Thierry, 1997;Chadwick and Lever, 2000;Shahabuddin and Khan, 2000), ribozymes targeting HIV-1 sequences (for a review, see Rossi, 2000), or intrabodies against HIV-1 proteins (Mhashilkar et al, 1995(Mhashilkar et al, , 1999. We isolated and characterized an HIV-1 nef allele (F12nef) whose expression in trans (D'Aloja et al, 1998) or in cis potently inhibits HIV-1 replication.…”