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输出是如何通过转录因子（TF）和辅助调节因子之间的特定合作来调节的。 DNA将TF引导至限定的基因组位点以调节基因的表达。 TF激活转录的能力关键取决于辅调节因子的募集，例如为了组装前起始复合物以起始转录。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序列诱导相关TF的替代构象，导致不同的调节活动。在此之前的工作中，我们已经确定了糖皮质激素受体（GR），激素依赖性TF的DNA结合位点序列特异性辅助调节因子。 具体来说，我们确定了共激活因子Brm和BATF 3以及共阻遏因子HDAC 10。 在这里，我们将采用体外的方法来研究如何DNA结合位点的序列影响GR的能力，这些和其他辅助调节相互作用。同时，我们将确定其作用的内源性GR-靶基因的调控，使用微阵列和确定的基因组位点，这些coregulators招募GR使用染色质免疫沉淀实验。总之，这些研究将提供新的见解，如何TF和辅调节剂合作，在一个上下文依赖性的方式来微调个别靶基因的表达水平。

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.