Project Summary/Abstract The major long-term objective of this research program is to understand the mechanisms of regulation of RNA polymerase II transcription in animals. Why is it important to study gene expression? The basis of a diverse range of biological phenomena, including many human diseases, can be traced to the proper or improper expression of a gene or set of genes. Thus, new insights into the mechanisms of gene expression will have a far-reaching impact upon the biological sciences. Specific emphasis will be placed upon the study of the RNA polymerase II core promoter, which is the short stretch of DNA that directs the initiation of transcription. Why is it important to study the core promoter? First, the core promoter is the "gateway to transcription" – the site of convergence of the signals that lead to transcription initiation. In this regard, the core promoter is at a key strategic position in the transcription process. Second, the core promoter is a central and integral component of the RNA polymerase II transcription system that comprises the signals in the chromatin (including DNA sequence motifs) and the factors that read those signals and carry out the transcription process. At present, core promoter elements are best understood in organisms other than humans. The human core promoter, which is complex and difficult to decipher, is the next challenge. Hence, future goals include the elucidation of the components of the human core promoter and the identification and analysis of the transcription factors that function with specific sequence elements to mediate the regulation of gene expression in humans. This work should provide new and important insights into the mechanisms of transcriptional regulation in humans. A second objective of this research program is to understand the diverse functions of chromatin – the natural form of DNA in the eukaryotic nucleus. Because DNA is the genetic material and is thus of the utmost importance, there is a strong and broad interest in the factors and mechanisms that affect chromatin and DNA structure and integrity. In particular, these processes will be investigated at the interface of chromatin and DNA – that is, in the context of chromatin rather than with DNA alone. One particular area of interest is the study of factors that protect DNA from damage by binding to nucleosomes. New insights into the protection of DNA against damaging agents such as reactive oxygen species would not only provide important fundamental knowledge of cellular function, but would also be relevant to the understanding and prevention of cancer.