Regulation of gene expression in eukaryotes is a highly dynamic process. We have developed an experimental system to measure turnover of the transcription machinery on a genome-wide scale in budding yeast as model system. Our studies revealed a cyclic behavior of active and inactive transcription complexes on gene promoters. In the current project we will investigate the parameters regulating the dynamic behavior of transcription complexes and relate this to the mRNA output of an eukaryotic genome. We will make use of well-characterized mutant versions of the TATA-binding protein and exploit our technological advantages in genome-wide mapping. In addition, a novel approach to inactivate essential proteins will be applied to determine their contributions to the activation/deactivation cycles of the transcription machinery. The combination of approaches will provide quantitative information on the contributions of DNA sequence and transcription factor action on the dynamic parameters of transcription complexes. This information will greatly contribute to a systems-biology based description of the eukaryotic transcription process.