Regulating CREB Mediated Transcription by HDAC Complexes

本申请的目的是深入了解通过磷酸化依赖性转录因子环腺苷酸反应元件结合蛋白（CREB）调控环腺苷酸（cAMP）介导的基因表达的分子机制。具体来说，我将集中在组蛋白脱乙酰酶复合物（HDAC）在调节CREB介导的转录中发挥的作用。我的假设是，HDAC复合物与CREB的关联通过破坏局部染色质结构并阻止暴露于cAMP激动剂的细胞中PKA对CREB的磷酸化来阻断细胞基因表达。为了验证这一假设，我将确定与CREB相互作用的HDAC复合物的组成部分。为了测试内源性HDAC复合物是否减弱CREB介导的转录，我还将表征不能与HDAC复合物缔合的突变CREB多肽。最后，我将测试HDAC介导的启动子结合核小体的脱乙酰化是否通过阻断PKA与染色质的结合来阻碍磷酸化。

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.