Notch Target Gene Regulation in Normal and Malignant T Cells

Notchl在T细胞前体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ChlP-Seq和生物信息学技术来描绘 Notchl与正常小鼠和人胸腺细胞基因组的相互作用。通过将这些关联起来 与染色质标记和基因表达的相互作用，我们将获得Notchl如何调节的全球视角 T细胞的发育，并将这些相互作用与Notchl在小鼠和人类T细胞中的相互作用进行比较， 我们将进一步深入了解正常与恶性之间的关键异同 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的调节 允许Notch1的转录因子CSL的序列配对结合位点(SPSS)的表达 二聚化。破坏二聚体Notch复合体的突变体不能诱导T-ALL，显示T细胞缺陷 发展，并失去上调关键靶基因的能力，如Myc和PTA。 这些相辅相成的调查工作将通过两个目标进行： 目的1：确定Notchl是如何调节T细胞发育的。我们将把ChlP-Seq与 识别全基因组Notch1/CSL结合位点的计算方法，表征特定的 控制关键Notch靶基因转录的反应元件，识别两个新的Notchl靶基因 基因，并阐明Notch用于调节P-选择和T细胞其他阶段的机制 发展。此外，T细胞正常发育阶段的表观遗传图景将是 与T-ALL细胞相比。 目的2：探讨二聚体Notch信号复合体在T-ALL中的作用。我们将识别并验证 二聚化依赖的Notch靶标和确定二聚化依赖的体内重要性 T细胞发育过程中的缺口信号。 总而言之，这些研究将提供对Notch如何 调节T细胞发育和T细胞转化，并在此过程中提供新的机会 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.