The goal of this application is to investigate the regulation of eukaryotic gene expression. The system chosen for experimentation is the transcriptional activation of specific viral and cellular genes elicited by adenovirus E1a. In this system of regulated gene expression, both the activator and targets are known and the mediating transcription factors, and the genes encoding these factors, are being identified, isolated and cloned. This application proposes to isolate the genes encoding factors thought to be essential for E1a dependent transcriptional stimulation of the human HSP70 gene, and to determine if and how these factors are altered by E1a. Characterization of these factors may reveal particular cellular complexes correlated with transcriptional activity. The dependence of E1a activation on each factor will be tested by constructing synthetic activators and targets. These experiments will separate the components important for activation from those important for promoter specificity. This approach may elucidate some of the rules governing eukaryotic gene regulation and the mechanisms that viruses have evolved to intercede and re- route cellular processes.