The long-term goals of this research are to understand the molecular mechanisms of eukaryotic transcription initiation and its regulation. A thorough understanding of transcriptional control mechanisms is key to understanding both normal and abnormal biological processes. The yeast Class III gene system is used here as a model system for investigating the molecular mechanisms of transcription and its regulation. This work represents a continuation of studies ongoing in our laboratory on the yeast Class III gene transcription apparatus. The approach to be used in these experiments will be multi-faceted combining biochemical and genetic analyses focusing primarily on the factors TFIIIB and TFIIIC. The interplay of these factors with each other, RNAPIII, and with factor TFIID (TBP) will be examined in detail. The various protein-DNA and protein-protein interactions between these components will be studied on both naked and nucleosomal templates. To accomplish these goals the following lines of experimentation will be pursued: (1) The genes encoding additional TFIIIB and TFIIIC subunits will be cloned and characterized with regard to their structure-function relationships. (2) The mechanisms of action of the class III gene transcription factors will be examined. Efforts will also be expended towards understanding the interplay between the Class III and Class II gene transcription machineries. (3) The role that chromatin structure plays in modulating Class III gene transcription complex formation, stability and elongation on a nucleosomal template will be investigated.
