The purpose of this study, now in its fourth year, is the analysis of the instruments and controls of Adenovirus gene expression in lytically infected or in transformed cell cultures. Projects under current investigation include (A) the identification of non-structural virus-specific proteins, (B) mapping of Adenovirus messenger RNA by electron microscopy, and (C) the processing of nuclear Adenovirus RNA. Electron microscopy is in part performed in collaboration with the research group headed by Dr. J. V. Maizel, Jr.