Identification and Characterization of Genes from del22q

描述（申请人提供）：Tbx1需要用于人类、小鼠和斑马鱼的心血管发育。自从最初认识到该基因在发育中的作用以来，在突变体分析方面取得了相当大的进展，导致了新的假设。Tbx1是一种T-box转录因子，是胚胎咽部分割、主动脉弓形成和心脏流出道形态发生所必需的。然而，如果我们不解决两个基本问题：Tbx1基因调控的关键参与者是什么，以及Tbx1蛋白的靶标是什么，那么对该基因的进一步了解将受到限制。Tbx1基因具有精细的动态调控，在这里，我们表明这与胚胎发生过程中的时间特异性作用有关。例如，早期表达是心血管发育所必需的，而晚期表达是胸腺器官发生和腭发育所必需的。此外，我们发现在心血管发育过程中，组织对Tbx1功能有特定的需求。该建议建立在这些新数据的基础上，以寻找在关键时间和组织中重要的Tbx1调节因子和靶点。

DESCRIPTION (provided by applicant): Tbx1 is required for cardiovascular development in human, mouse and zebra fish. Since the initial recognition of the role of this gene in development, there has been considerable progress in the analysis of mutants that led to novel hypotheses. Tbx1 is a T-box transcription factor required for segmentation of the embryonic pharynx, patterning of the aortic arch, and morphogenesis of the outflow tract of the heart. However, further knowledge acquisition about this gene would be limited if we do not address two fundamental questions: what are the critical players in the regulation of the Tbx1 gene, and what are the targets of the Tbx1 protein. The Tbx1 gene has an exquisitely dynamic regulation, and here we show that this is associated with time-specific roles during embryogenesis. For example, early expression is required for cardiovascular development while late expression is required for thymic organogenesis and palatogenesis. In addition, we show tissue specific requirements for Tbx1 function during cardiovascular development. This proposal builds upon these new data to search for regulators and targets of Tbx1 that are important at the critical times and tissues. The overall aim is to establish hard links in the genetic pathway within which Tbx1 functions. We believe that this work will lead to genes causing or modifying congenital heart disease. In the first specific aim we will use novel approaches to identify genetic elements necessary for Tbx1 regulation in the pharyngeal endoderm, a key tissue for Tbx1 function, and will also determine if Tbx1 expression in this tissue is sufficient to rescue the cardiovascular abnormalities seen in mutants. In the second specific aim, we will use a combination of transcriptome analysis and chromatin immunoprecipitation assay to identify transcriptional targets. Preliminary data show the power of this approach. In addition, we propose in vitro and in vivo validation of candidate target genes. This project addresses directly the function of Tbx1 in cardiovascular development as defined by upstream regulation of the gene and transcriptional targets of the protein in relevant tissues. Data should provide the dissection of a genetic network disrupted in DiGeorge and Velocardiofacial syndromes, and possibly in other genetic disorders affecting cardiovascular development.