One goal of this proposal is to determine whether the phosphorylated CREB-CBP complex provides a model for transcription factors that interact with CBP in a phosphorylation-independent manner. The specific goal is to generate a CREB mutant that can interact with CBP constitutively. This mutant will be used to test whether CBP recruitment is sufficient for CREB-mediated gene transcription, and to determine whether second messenger signals, in addition to CREB activation, also affect transcriptional events downstream from CBP recruitment. The second goal is based on the hypothesis that transcription factor co-activator binding creates protein interaction surfaces that allow the association of additional factors required for gene expression. Using a genetic screen in yeast, several such factors have been identified. The contributions of these interacting proteins, which appear to be involved in either chromatin modification or transcriptional elongation, to transcription will be tested by binding and functional assays using a reconstituted chromatin transcription system.
