Regulatory mechanism of HIV-ltranscription and its therapeutic control

点击翻译按钮获取中文摘要

In an attempt to identify the cellular target genes for HIV-encocled Tat, we have performed gene expression profile analysis and fund OGG1, the gene encoding an enzyme responsible for the repair of 8-oxo-dG, an damaged Guanine residue due to the action of radieal oxygen species (ROS). Among the as-regulatory elements located within the promoter of OGG1 gene, we have identified AP-4 sites to be responsible for the Tat-mediated OGG1 upregulation. When AP-4 sites were mutated the OGG1 gene expression was upregulated, indicating that AP-4 plays a negative role in OGG1 gene expression, and the effect of Tat was abolished. Using chromatin immunoprecipitation (ChIP) assay we fund that AP-4 binds to these AP-4 sites on the OGG1 promoter and AP-4 was reliesed from the OGG1 promoter upon Tat transduction. We also fund that Tat binds to AP-4 by immunoprecipitation followed by Western blotting. When the amounts of 8-oxo-dG level were measured, we found the dramatic decrease of the 8-oxo-dG upon Tat transduction. These findings indicate a possibility that Tat plays a role in Maintaining the genomic integrity of the HIV-infected cells and HIV proviral DNA.We also examined the effect of a novel inhibitor of IKK that is primarily involved in the signal induced HIV replication from the latently infected cells. The HIV production was greatly augmented by stimulating cells infected with HIV and the pretreatment of cells with ACHP greatly inhibited the viral production under non-cytotoxic concentrations with IC 50 and CC50 values of 0.5 μM and 15 μM, respectively (therapeutic window being approximately 30). These findings suggest that ACHP and its derivatives may have therapeutic effect to prevent AIDS development by preventing HIV replication from the latently infected cells.