Specific antibody probes will be prepared against the dozen early proteins whose genes have been mapped within the regions of adenovirus type 2 (Ad2) that are related to oncogenic transformation. These same regions of the genome are also involved in viral gene regulation and DNA replication. To prepare monospecific and monoclonal antibodies against these proteins, which are present in cells in very small amounts, animals will be immunized with chemically synthesized peptides or with chimeric proteins encoded by recombinant plasmids that contain Ad2 DNA. These antibodies will be used to purify several early proteins, and to characterize the associations of early protein with viral DNA, with chromatin, and with heterogeneous nuclear RNP. Antibodies and purified proteins will be used with appropriate cell-free systems to identify the roles of these proteins in viralgene regulation and in DNA replication. Information on these elements of the productive infection of adenovirus will be correlated with possible molecular mechanisms of oncogenesis.