Identification of downstream signals for Pitx2a

描述（由申请人提供）： Pitx 2是一种bicoid型同源结构域转录因子，与人类的Rieger综合征有关，并在介导小鼠、鸡、青蛙和斑马鱼的左右发育中起重要作用。 据信，细胞增殖、细胞运动以及局部区域中细胞命运的指示信号的变化对于指导器官发生期间的左右不对称是重要的。 作为一种转录因子，Pitx 2应该激活和/或抑制其靶基因的转录以执行特定的细胞功能。 然而，人们对Pitx 2的下游靶点和信号通路知之甚少。 本研究旨在寻找Pitx 2亚型之一Pitx 2a调控的靶基因及其相关信号通路。 我将使用一种异位表达Pitx 2a的诱导型HeLa细胞系，该细胞系已经在实验室中可用。 这种可诱导的细胞系将允许我基于细胞表型追踪Pitx 2a的下游信号通路，并通过比较在诱导和未诱导条件下从细胞中分离的RNA来鉴定Pitx 2a的靶基因。 转基因小鼠模型也将用于评估推定的下游靶基因在小鼠中介导Pitx 2a功能的重要性。 使用这些细胞培养和小鼠模型系统鉴定这些下游靶基因和信号通路应该使我能够进一步理解Pitx 2a功能的机制以及Pitx 2a表达与其在胚胎发育过程中的形态发生作用之间缺失的联系。

DESCRIPTION (provided by applicant): Pitx2, a bicoid-type homeodomain transcription factor, has been implicated in Rieger's syndrome in humans and plays an important role in mediating left-right development in mice, chickens, frogs and zebrafish. It is believed that cell proliferation, cell motility as well as changes in instructive signals for cell fate in local areas are important for directing left-right asymmetry during organogenesis. As a transcription factor, Pitx2 should activate and/or repress the transcription of its target genes to execute specific cellular functions. However, little is known about the downstream targets and signaling pathways for Pitx2. I propose in this study to search for the target genes regulated by Pitx2a (one of the Pitx2 isoforms) and the relevant signaling pathways. I will use an inducible HeLa cell line ectopically expressing Pitx2a, which is already available in the laboratory. This inducible cell line will allow me to trace the downstream signaling pathways for Pitx2a based on cell phenotype and to identify the target genes for Pitx2a by comparing the RNA isolated from cells under the induced and uninduced conditions. The transgenic mouse model will also be used to assess the importance of the putative downstream target genes in mediating the function of Pitx2a in mice. Identification of these downstream target genes and signaling pathways using these cell culture and mouse model systems should allow me to make progress towards understanding of the mechanism underlying the functions of Pitx2a as well as the missing links between Pitx2a expression and its roles in morphogenesis during embryonic development.