Fine-tuning transcriptional activity of transcriptional regulatory factors by DNA-sequence induced selective use of coregulators

该项目的目标是了解转录因子（tf）和协同调节因子之间的特定环境合作如何调节转录输出。DNA引导tf到定义的基因组位点来调节基因的表达。tf激活转录的能力严重依赖于共调节因子的招募，例如，为了组装起始前复合物以启动转录。传统上认为，DNA结合位点的作用仅限于招募tf。然而，最近的研究表明，DNA序列在相关的TF中诱导不同的构象，从而导致不同的调控活性。在此提案之前的工作中，我们已经确定了糖皮质激素受体（GR）的DNA结合位点序列特异性共调节因子，这是一种激素依赖性TF。具体来说，我们确定了共激活因子Brm和BATF3以及共抑制因子HDAC10。在这里，我们将采用体外方法来研究DNA结合位点的序列如何影响GR与这些和其他共调节因子相互作用的能力。同时，我们将利用微阵列确定它们在内源性GR靶基因调控中的作用，并利用染色质免疫沉淀实验确定GR募集这些共调节剂的基因组位点。总之，这些研究将提供新的见解，了解tf和协同调节因子如何以上下文依赖的方式合作，微调单个靶基因的表达水平。

The goal of this project is to understand how transcriptional outputs are modulated by context-specific cooperations between transcription factors (TFs) and coregulators. DNA guides TFs to defined genomic loci to regulate the expression of genes. The ability of TFs to activate transcription critically depends on the recruitment of coregulators for example in order to assemble the pre initiation complex to initiate transcription. The role of DNA binding sites was traditionally thought to be restricted to simply recruiting TFs. Recent studies however revealed that DNA sequences induce alternative conformations in the associated TF resulting in different regulatory activities. In work preceding this proposal we have identified DNA binding site sequence-specific coregulators of the glucocorticoid receptor (GR), a hormone dependent TF. Specifically, we identified coactivators Brm and BATF3 and a corepressor HDAC10. Here we will employ in vitro approaches to study how the sequence of DNA binding sites influences the ability of GR to interact with these and other coregulators. In parallel, we will determine their role in the regulation of endogenous GR-target genes using microarrays and determine the genomic loci to which these coregulators are recruited by GR using chromatin immunoprecipitation experiments. Together, these studies will provide novel insights into how TFs and coregulators cooperate in a context-dependent manner to fine-tune the expression levels of individual target genes.