TRANSCRIPTION CONTROL BY THE NUCLEAR ONCOPROTEIN, E1A

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The long term goal of this proposal is to elucidate the transcription regulatory pathways that are also targets of oncogene action such as the adenovirus ElA. Several oncogene products have been identified. Determination of the biochemical functions of these oncogene products will eventually elucidate the pathways that lead to transformation and tumorigenesis. Evidence is accumulating that the majority of the oncogene products are involved in the control of gene expression. This proposal involves functional analysis Of ElA oncogene products with regard to their effect on the activities on the cellular proteins such as E2F, E4F and E2FBP. E2F and E4F are cellular transcription factors that are involved in the control of the adenovirus early genes. E2FBP is an E2F binding protein that modulates E2F activity by forming a complex with E2F which in turn is regulated by ElA proteins.ElA dissociates E2F/E2FBP complex requiring the domains 1 and 2 of ElA and these two domains are also involved in the transformation function of this oncoprotein. Thus a major focus of this proposal is biochemical characterization of E2FBP and production of specific antisera against E2FBP which will help analyzing the basis of ElA control. The SV40 T antigen and the HPV E7 protein possess sequence homology with domains 1 and 2 of ElA and these two oncoproteins also trans-activate adenovirus E2 promoter depending on the E2F binding site. These two proteins will also be analyzed for their ability to control E2F/E2FBP interaction. The other interest of this proposal is to analyze the mechanism that control the DNA binding activity of the ElA-regulated transcription factor E4F. Specific reagents, like peptide antisera and cDNA clones, will be obtained using the peptide sequence information. These reagents will be extremely valuable in the studies of E4F regulation by phosphorylation as well as by the adenovirus ElA gene products. The proposal also focuses on identification of a cellular kinase that might be involved in the regulation of E4F DNA binding activity.