Growth Hormone Signaling to the Nucleus

描述（申请人提供）：生长激素（GH）对生长和代谢具有深远的生理影响，与胰岛素抵抗和可能的癌症有关。许多对生长激素的反应依赖于其调节基因转录的能力。我们假设gh调控的转录是由多组分核蛋白复合物在靶基因上的有序组装介导的，并且gh诱导的关键蛋白修饰可以引导它们进入或退出复合物。我们的方法是使用染色质免疫沉淀（ChIP）和re-ChIP分析多组分复合物在GH响应下的组装，以定义GH调节的复合物组分，并确定模型基因c-fos上的组装动力学。同时，我们还将研究GH诱导的转录因子C/EBPp的翻译后修饰，这对于GH刺激的C -fos转录至关重要。复合物组装的顺序将与C/EBPp翻译后修饰（包括磷酸化、乙酰化和sumo化）的时间和组合有关。当GH对复合物的调控被确定后，我们将验证它们对GH调控基因在体内表达的功能重要性。相关性：生长激素用于治疗生长激素缺乏症的矮小。生长激素的合成代谢特性被用于治疗，以改善伤口愈合和逆转艾滋病毒患者的消瘦。然而，生长激素也会导致糖尿病并降低对胰岛素的敏感性。最近，GH- igf轴与癌症有关，扩大了我们对GH作用基础的了解。提出的研究将提供关于生长激素如何通过调节基因改变细胞功能的基本信息。有了这些信息，我们可以确定新的分子靶点，以开发对生长激素有反应的疾病更有效的治疗方法，并避免糖尿病和癌症等疾病的生长激素相关并发症。

DESCRIPTION (provided by applicant): Growth hormone (GH) exerts profound physiological effects on growth and metabolism, and is implicated in insulin resistance and possibly cancer. Many responses to GH depend on its ability to regulate gene transcription. We hypothesize that GH-regulated transcription is mediated by the ordered assembly of multicomponent nucleoprotein complexes on target genes and that GH-induced modifications of critical proteins can direct them into and out of the complexes. Our approach is to dissect the assembly of the multicomponent complexes in response to GH using chromatin immunoprecipitation (ChIP) and re-ChIP to define GH-regulated components of complexes and determine the dynamics of assembly on the model gene c-fos. In parallel, we will also examine post-translational modifications induced by GH on the transcription factor C/EBPp, which is essential for GH-stimulated transcription of c-fos. The sequence of complex assembly will be related to the timing and combinations of post-translational modifications of C/EBPp including phosphorylation, acetylation and sumoylation. When regulation of complexes by GH is determined, we will validate their functional importance for GH-regulated gene expression in vivo. Relevance: GH is used for treatment of short stature in GH deficiency. The anabolic properties of GH are being used therapeutically to improve wound healing and to reverse wasting in HIV patients. However, GH is also diabetogenic and reduces sensitivity to insulin. Recently, the GH-IGF axis has been implicated in cancer, broadening our need to understand the basis of GH action. The proposed studies will provide fundamental information about how GH alters cell function by regulating genes. With this information, we can identify new molecular targets to develop more effective therapies for conditions responsive to GH and to avoid GH-related complications in conditions such as diabetes and cancer.