Notch Target Gene Regulation in Normal and Malignant T Cells

Notchl在T细胞祖细胞中的致癌活性似乎代表了其正常水平的夸大。 在T细胞发育过程中发挥作用。我们将使用新的ChIP-Seq和生物信息学技术来描绘 Notchl与正常鼠和人胸腺细胞基因组的相互作用。通过将这些 与染色质标记和基因表达的相互作用，我们将获得Notchl如何调节的全局视图 T细胞发育，并通过比较这些相互作用与Notchl在鼠和人T-ALL中的相互作用， 我们将进一步深入了解正常和恶性之间的关键相似性和差异， 胸腺细胞 Notchl与正常和恶性胸腺细胞相互作用的第二个关键方面是基因调控。 通过转录因子CSL的序列配对结合位点（SPS）表达， 二聚化。破坏二聚Notch复合物的突变体不能诱导T-ALL，显示T细胞缺陷 这些基因的表达会导致细胞的发育，并失去上调关键靶基因如Myc和pTa的能力。 将通过以下两个目标开展这些相辅相成的调查： 目的1：确定Notchl如何调节T细胞发育。我们将联合收割机ChIP-Seq与 计算方法，以确定Notch 1/CSL结合位点的基因组范围内，表征特定的 控制关键Notch靶基因转录的应答元件，鉴定了两种新的Notchl靶基因， 基因，并阐明Notch用于调节P-选择和T细胞的其他阶段的机制 发展此外，T细胞发育的正常阶段的表观遗传景观将是 与T-ALL细胞相比。 目的2：探讨Notch信号复合物在T-ALL中的作用。我们会确认 二聚化依赖性Notch靶向并确定二聚化依赖性Notch靶向的体内重要性。 T细胞发育过程中的Notch信号传导。 总之，这些研究将提供一个全面的分子和基因组的理解， 调节T细胞发育和T细胞转化，并在此过程中提供了新的机会， 在T-ALL和其他疾病中合理靶向Notch通路。

Notchl's oncogenic activity in T cell progenitors appears to represent an exaggeration of its normal functions during T cell development. We will use new ChlP-Seq and bioinformatic technologies to delineate the interaction of Notchl with the genomes of normal murine and human thymocytes. By correlating these interactions with chromatin marks and gene expression, we will gain a global view of how Notchl regulates T cell development, and by comparing these interactions with those of Notchl in murine and human T-ALLs, we will further gain a deep understanding of key similarities and differences between normal and malignant thymocytes. A second key aspect of Notchl interaction with normal and malignant thymocytes is regulation of gene expression through sequence-paired binding sites (SPSs) for the transcription factor CSL that permit Notchl dimerization. Mutants that disrupt dimeric Notch complexes cannot induce T-ALL, show defects in T cell development, and lose the ability to upregulate key target genes such as Myc and pTa. These complementary lines of investigation will be pursued through two aims: Aim 1; To determine how Notchl regulates T cell development. We will combine ChlP-Seq with computational approaches to identify Notch1/CSL binding sites genome-wide, characterize the specific response elements that control transcription of key Notch target genes, identify both novel Notchl target genes, and elucidate mechanisms used by Notch to regulate p-selection and other stages of T cell development. In addition, the epigenetic landscapes of normal stages of T cell development will be compared to T-ALL cells. Aim 2: To determine the role of dimeric Notch signaling complexes in T-ALL. We will identify and validate dimerization-dependent Notch targets and determine the in vivo importance of dimerization-dependent Notch signaling during T cell development. Together, these studies will provide a comprehensive molecular and genomic understanding of how Notch regulates T cell development and T cell transformation, and in doing so provide new opportunities to rationally target the Notch pathway in T-ALL and other diseases.