Host-dependent processes for HIV-1 replication make viable targets for drugs against which HIV-1 might not be able to devise protective mutations. In an attempt to more broadly identify host-dependent processes in HIV-1 replication will use retroviral mediated complementation cloning to deliver libraries of aptamer compounds (as Dominant Effectors (DEs) of intracellular signaling) as well as cDNAs into target cells, coupled with genetic selection schemes, to develop reagents that block HIV-1 entry and establishment processes. Selection systems will be those dependent upon NFAT activity and more broadly acting on HIV-1 post-entry processes. The aptamers and cDNAs will be used to pinpoint cellular processes that are required for HIV-1 establishment and replication. We propose that the dominant effector cloning systems discussed here, when applied to the screens to be described, will also provide reagents for further biological inquiry into NFAT and NF-kappaB signaling systems in T cells on which HIV-1 depends in T cells. The approach provides these aptamer as potential affinity reagents to isolate proteins with which they interact in pathways. This allows for characterization of these proteins, and the pathways in which they are involved, for potential use as therapeutic targets. In a sense, with such intracellularly expressed dominant effector aptamers, interference with a target protein that results in the desired phenotype validates that target protein as a potential therapeutic target for small-molecule drug discovery. An example of a host factor we have already defined as regulating key determinant of HIV-1 parasitism is the Nuclear Factor of Activated T cells. NFAT is a crucial contributor to the activation of HIV-1 transcriptional regulation through the HIV-1 enhancer, and an important component of the activation requirements for completion of reverse transcription in activated T cells. In normal CD4+ T cells NFAT activation of a cellular pathway is apparently critical for HIV-1. Since it is clear a pathway exists in T cells on which HIV-1 replication is dependent to an extent it is not dependent in other cell types we will further characterize the nature of the host target pathways that restrict HIV-1 replication. One downstream result of NFAT activation in T cells is direct HIV-1 activation through binding and interaction at the Rel binding sites of the core kappaB promoter in HIV-1. Therefore, another hypothesis to be explored is that NFAT and NF-kappaB can focus their transcriptional activities by coordinate binding at the HIV-1 enhancer motifs. The roles of these evolutionarily disparate Rel molecules in T cells will be dissected with regards to their activity upon the HIV-1 enhancer and promoter region.
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