The goal of this application is to gain insight into the molecular mechanisms that govern cyclic AMP (cAMP)-mediated gene expression through the phosphorylation-dependent transcription factor, cyclic AMP response element binding-protein (CREB). Specifically, I will be focusing on the role that histone deactylase complexes (HDAC) play in regulating CREB-mediated transcription. My hypothesis is that the association of HDAC complexes with CREB block cellular gene expression by disrupting local chromatin structure and preventing phosphorylation of CREB by PKA in cells exposed to cAMP agonist. To test this hypothesis, I will identify components of the HDAC complexes that interact with CREB. To test whether endogenous HDAC complexes attenuates CREB-mediate transcription, I will also characterize mutant CREB polypeptides that are unable to associate with the HDAC complex. Finally, I will test whether HDAC-mediated deacetylation of promoter-bound nucleosomes hinders phosphorylation by blocking the association of PKA with chromatin.
