Structural Studies of the Vitamin D Receptor

描述(申请人提供)：类固醇和核激素受体 是已知的最大一类真核转录调控因子 调节转录，以响应非肽类脂溢性信号。这个 这个超家族的成员包括维生素D受体(VDR)，它 调节与钙稳态相关的基因，并在 造血细胞和皮肤细胞的分化与雄激素受体 (AR)，直接调节前列腺特异性基因的表达，其中 其他。 激素受体通过以同二聚体或异二聚体的形式与 DNA靶标--称为反应元件--由两个六核苷酸组成 半边-通过半边的顺序相互区分的位置 场地和一个半场地相对于另一个场地的方向和间距。 VDR与由直接排列的两个半位点组成的反应元件结合 重复其间的三个碱基对的间隔区(DR-3)。AR绑定到倒置 重复的三间隔反应元件(IR-3)，尽管最近发现了一种新的AR 确定了与DR-3型非常相似的反应元件，并可能 用来区分AR反应基因和那些对 糖皮质激素和其他类固醇。 对VDR和AR在脑出血中作用的潜在立体化学的理解 转录激活和DNA靶标选择需要结构 相关大分子物种和络合物的分析。我们计划解决 并用X射线结晶学分析了DNA结合的结构 VDR同源二聚体和RXR-VDR异源二聚体的结构域与多种 DNA靶点，以及与其形成的复合体中AR DNA结合域的结构 新的直接重复DNA靶点。这些研究的目的是阐明 VDR和AR DNA目标识别的结构基础，它们共享 DR-3型反应元件的偏好，以及用于 区分正确和错误的DNA目标。我们将把我们的 与蛋白质结合亲和力测量的结构结果 共识和野生型反应要素。将使用核磁共振和结晶学 并行和协同地研究全长VDR的结构，在 为了了解DNA和配体结合域之间的相互作用。 这些分析可能导致新的抗癌或治疗药物的设计 化合物。

DESCRIPTION (provided by applicant): The steroid and nuclear hormone receptors are the largest known class of eukaryotic transcriptional regulators and modulate transcription in response to non-peptide lipophillic signals. The members of this superfamily include the vitamin D receptor (VDR), which regulates genes related to calcium homeostasis and plays a role in the differentiation of hematopoietic and skin cells, and the androgen receptor (AR), which directly regulates the expression of prostate-specific genes, among others. Hormone receptors exert their effects by binding as homo- or hetero-dimers to DNA targets - called response elements - composed of two hexanucleotide half-sites that are distinguished from one another by the sequence of the half site and the orientation and spacing of one half site relative to the other. VDR binds to response elements composed of two half-sites arranged as a direct repeat with three base pairs of spacer in between (DR-3). AR binds to inverted repeat, three-spacer response elements (IR-3), although recently a novel AR response element was identified that closely resembles the DR-3 type and may serve to distinguish AR responsive genes from those responsive to glucocorticoids and other steroids. An understanding of the underlying stereochemistry of the role of VDR and AR in transcriptional activation and DNA target selection requires the structural analysis of the relevant macromolecular species and complexes. We plan to solve and analyze, using X-ray crystallography, the structures of the DNA binding domain of VDR homodimers and RXR-VDR heterodimers in complex with a variety of DNA targets, and the structure of the AR DNA binding domain in complex with its novel direct repeat DNA target. These studies are aimed at elucidating the structural basis for both VDR and AR DNA target recognition, their shared preference for DR-3 type response elements, and the mechanisms employed to distinguish correct from incorrect DNA targets. We will correlate our structural results with measurements of the protein's binding affinity to consensus and wild-type response elements. NMR and crystallography will be used in parallel and synergistically to examine the structure of full-length VDR, in order to understand the interplay between the DNA and ligand binding domains. These analyses may lead to the design of novel anti-cancer or therapeutic compounds.