Mechanisms of Transcriptional Regulation in Eukaryotes

University Of California San Diego, La Jolla CA

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Abstract

DESCRIPTION (provided by applicant): The long-term objective of this project is to understand the mechanisms by which transcription by RNA polymerase II is regulated in eukaryotes. This project focuses upon the core promoter motif termed the DPE (downstream core promoter element). The DPE is somewhat analogous to the TATA box, as both are recognition sites for the binding of TFIID. Yet, there are significant differences in the mechanisms of basal transcription from DPE- versus TATA-dependent core promoters. For instance, NC2 is an activator of DPE-dependent transcription and a repressor of TATA-dependent transcription. Interestingly, some transcriptional enhancers possess strict specificity for promoters that contain either DPE or TATA motifs. These findings indicate that there are specific and essential interactions between transcriptional enhancers and DPE or TATA motifs in the core promoter. The Specific Aims are as follows: 1. Investigate the specific DNA sequences and protein-DNA interactions that are involved in DPE function. This aim is directed toward gaining a better understanding of the sequences that mediate DPE function as well as the interaction of TFIID and other factors with DPE-dependent promoters. 2. Purify and characterize the basal factors that mediate transcription from DPE-dependent core promoters. The basal transcription factors that transcribe TATA-dependent promoters are not sufficient for transcription of DPE-dependent promoters. Therefore, the aim of these experiments is to purify and to characterize the remaining factors that are necessary for transcription from DPE-dependent core promoters. 3. Investigate the molecular basis of enhancer-core promoter specificity, particularly with DPE-specific enhancers. The aim of these experiments is to identify and to characterize the cis-acting DNA elements and trans-acting factors that are responsible for DPE-specific enhancer (and TATA-specific) activity. These studies should contribute to our fundamental understanding of gene expression and should be applicable to the analysis of human diseases that might be treated by the specific control of the transcription process.