These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Construction and characterization of a potent HIV-2 Tat transdominant mutant protein.
    Author: Echetebu CO, Rhim H, Herrmann CH, Rice AP.
    Journal: J Acquir Immune Defic Syndr (1988); 1994 Jul; 7(7):655-64. PubMed ID: 8207644.
    Abstract:
    The human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) Tat proteins Tat-1 and Tat-2 stimulate transcription of the viral long terminal repeat (LTR) sequences and are required for efficient viral replication. A class of mutant Tat proteins, termed "transdominant mutants," has been described that possesses relatively low transactivation activity, yet is able to inhibit the function of wild-type Tat. These mutant proteins contain a nonfunctional TAR RNA-binding domain but apparently retain a functional activation domain. A potential limitation for therapeutic use of transdominant mutants described to date is their low but significant basal level of transactivation for the HIV-1 or HIV-2 LTRs. In order to make an improved transdominant mutant, we have constructed Tat-2 proteins that contain mutations in four contiguous arginines at residues 81 to 84 in the RNA-binding domain. Using purified proteins and in vitro RNA-binding assays, we verified that these mutant Tat-2 proteins are defective for TAR RNA binding. We also verified that these mutant Tat-2 proteins bind to a cellular protein kinase in vitro that we have previously shown to bind specifically to the Tat-1 and Tat-2 activation domain. Using plasmid cotransfection assays, we compared the phenotypes of these mutant Tat-2 proteins with the most potent Tat-1 transdominant mutant described to date. One Tat-2 mutant, named "R81-84A," was found to be equivalent to the Tat-1 mutant in ability to inhibit wild-type Tat transactivation of HIV-1 and HIV-2 LTRs. Moreover, the R81-84A mutant possessed a significantly lower basal level of transactivation than the Tat-1 mutant. The R81-84A Tat-2 mutant is therefore a promising reagent for future development as an anti-HIV agent. Additionally, our results suggest that wild-type Tat-2 transactivation of the HIV-2 LTR is especially sensitive to inhibition by transdominant mutants.
    [Abstract] [Full Text] [Related] [New Search]