Comparative Genetics of the DiGeorge Syndrome Gene TBX1

描述（由申请方提供）：Velo心面综合征和DiGeorge综合征（VCFS/DGS）是最常见的人类发育障碍，由单倍不足引起。大多数患者是人类染色体22 q11上3 Mb缺失的半合子。患有VCFS/DGS的患者在源自神经嵴的组织和器官系统中具有许多异常。这些包括面部畸形，心血管缺陷，免疫系统缺陷和许多其他缺陷。使用小鼠作为模型系统，PI已经能够显示过表达或表达减少的Tbx 1（位于缺失区间的基因）的小鼠在VCFS/DGS患者中受影响的许多器官系统中存在缺陷。TBX 1编码一种对正常神经嵴发育至关重要的转录因子。虽然有关TBX 1作用机制的信息正在出现，但还没有系统的努力来确定TBX 1作用的途径和网络。PI建议这样做。TBX 1在进化过程中是高度保守的，该基因在斑马鱼中的突变，命名为货车gogh（vgo），发展出与在VCFS/DGS患者中观察到的表型相似的表型。基于这些结果，PI现在提出了斑马鱼和小鼠中TBX 1通路和网络的比较遗传学分析。他们建议在适当的发育阶段使用正常和突变斑马鱼和小鼠胚胎的基因表达谱，以发现其表达模式因TBX 1蛋白减少或缺失而改变的基因。他们将使用整体原位杂交方法来研究斑马鱼中大量这些基因表达的时空模式。还将在Tbx 1突变斑马鱼和小鼠中检查一个子集。其表达模式与TBX 1或适当细胞和组织中的表达模式相匹配的基因将通过过表达和基于吗啉代的敲除在斑马鱼中进行遗传分析。如果这些基因中的一些突变体是可用的，则将单独或与TBX 1突变体组合检查它们。在某些情况下，PI将在小鼠中产生无效和条件突变等位基因，以检查它们在发育中的作用。将斑马鱼和小鼠与高通量遗传和基因组方法结合使用，有望提供有关TBX 1运作的途径和网络的丰富信息。

DESCRIPTION (provided by applicant): Velo cardio facial syndrome and DiGeorge syndrome (VCFS/DGS) are the most common human developmental disorders that result from haploinsufficiency. Most of the patients are hemizygous for 3 Mb deletion on human chromosome 22q11. Patients with VCFS/DGS have a number of abnormalities in tissues and organ systems that are derived from the neural crest. These include facial dysmorphology, cardiovascular defects, immune system defects and many others. Using the mouse as a model system the PIs have been able to show that mice that either overexpress or have reduced expression of Tbx1, a gene located in the deleted interval, have defects in many of the organs systems affected in VCFS/DGS patients. TBX1 encodes a transcription factor that is critical for normal neural crest development. Although information about the mechanisms of action of TBX1 is emerging, no systematic efforts to identify the pathways and networks in which TBX1 acts have been undertaken. The PIs propose to do so. TBX1 is highly conserved during evolution and mutations of this gene in the zebrafish, designated van gogh (vgo), develop phenotypes that are similar to those seen in VCFS/DGS patients. Based on these results, the PIs now propose a comparative genetics analysis of the TBX1 pathways and networks in zebrafish and mice. They propose to use gene expression profiling of normal and mutant zebrafish and mouse embryos at the appropriate developmental stages to discover genes whose expression patterns are altered as a result of reduction or absence of TBX1 protein. They will use whole mount in situ hybridization methods to examine the spatiotemporal patterns of expression of a large number of these genes in zebrafish. A subset will also be examined in Tbx1 mutant zebrafish and mice. Genes whose expression patterns match that of TBX1 or in appropriate cells and tissues will be subjected to genetic analysis in zebrafish through overexpression and morpholino-based knock-downs. If mutants for some of these genes are available, they will be examined alone and in combination with TBX1 mutants. In some cases the PIs will generate null and conditional mutant alleles in mice to examine their role in development. The combination of the use of zebrafish and mouse together with high throughput genetic and genomic approaches promise to provide rich information about the pathways and networks in which TBX1 operates.