The objective of this work is to elucidate mechanisms involved in the regulation of viral gene transcription. The initial emphasis is on those genes which encode the VA RNAs and which are transcribed by host RNA polymerase III in infected cells. These genes, as well as cellular 5S genes, have been shown to be accurately transcribed by a purified RNA polymerase III using either crude nuclear templates or purified DNA templates incubated with other cellular factors. In future studies we will 1) purify the factors necessary for the transcription of the purified genes by the purified RNA polymerase; 2) determine whether they are the same for different cellular and viral genes transcribed by RNA polymerase III; 3) determine whether these factors are sufficient to activate the same genes in standard viral nucleoprotein or cellular chromatin structures and, if not, 4) search for other cellular or viral induced transcription factors which act in conjunction with these factors; 5) investigate the mechanism(s) of action of the various transcription components in terms of sequence specific binding to DNA, the induction of chromatin structural modifications, etc. With respect to genes which encode mRNAs and which are transcribed by RNA polymerase II we will focus on the major late transcription unit and the left-most early transcription unit in adenovirus infected cells. These studies will involve attempts to reconstruct specific transcription events using approaches similar to those employed for the class III genes.