The long-term objectives of this proposal are to detail the molecular mechanisms regulating transcription and replication of vesicular stomatitis virus (VSV) and its defective interfering particles (DI). This prototype negative-strand rhabdovirus is readily grown in large quantities and is an excellent model system for numerous other disease-causing viruses as well as basic mechanisms of cellular gene expression. Only three virion- associated proteins (L polymerase, NS transcription factor, and nucleocapsid N protein) are sufficient to carry out a complex genome transcription process in vitro. NS is regulated by phosphorylation and contains an acidic activating domain which probably functions like that found in many eukaryotic cellular transcription factors. We plan to purify the virion-associated protein kinase(s) responsible for activating VSV transcription. Specific NS protein domain II substrates will be prepared to monitor this purification. The physical and biochemical properties of this purified kinase will be examined to shed light on the question of whether this activity is encoded by the virus or host genome. Basic studies of viral genetics such as this one not only provide an understanding of how viruses grows and develop but also provide information about generalized genetic functions in animal cells.