Determine general conditions favorable for the uptake of foreign deoxyribonucleic acid (DNA) by mammalian cells, investigating a variety of different parameters as well as the efficacy of adding various facilitators together with purified DNA preparations. Attempt to demonstrate biological activity by the heterologous DNA using two distinct specific markers: HGPRTase activity (the use of selective media will allow quantitation of the number of recipient cells rendered enzyme-positive in a given experiment); and attachment of picornaviruses to cells after exposure to primate cell DNA, which naturally lack specific receptor sites. Attempt to determine if transduction by SV40 pseudovirions is feasible and, if so, to compare their efficiency for gene-transfer to that accomplished by direct DNA applications. Quantitate the intracellular fate of exogenous DNA in recipient cells. Eventually explore the underlying mechanisms controlling exogenous gene expression.