PRRX REGULATION OF EXTRACELLULAR MATRIX GENES DURING CRANIOFACIAL DEVELOPMENT

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 腭裂是人类最常见的颅面畸形之一，影响约1/1000的活产婴儿。然而，在融合之前控制次级腭形成的分子机制还没有很好地理解。我们最近发现Prrx 1同源框转录因子缺陷的小鼠100%纯合子后代出现腭裂缺陷，这是由于缺乏垂直腭裂。这种缺陷在Prrx 1/Prrx 2双缺陷胚胎中更为严重。最近，一项SNP研究将PRRX 1确定为腭裂出生缺陷的候选基因。因此，我们的Pre突变小鼠是一个相关的和新的小鼠模型，可能有助于揭示参与正常的继发性腭裂和腭裂形成的遗传电路。我们已发表和未发表的研究结果表明，几个细胞外基质基因是Prrx 1的直接下游目标，并在次生腭发育过程中强烈表达。我们的初步数据表明，Prrx 1特异性结合蛋白聚糖多功能蛋白聚糖的启动子，在体外和体内。此外，我们的数据显示，在Prrx 1缺陷小鼠的次级腭中的畸形发生的早期发作时，与WT同窝出生的小鼠相比，腭架中的多功能蛋白聚糖水平显著增加。由于Prrx 1在E13.5时在次级腭间充质中强烈表达，我们假设Prrx 1在次级腭形成过程中直接调节versican的表达，并在次级腭形态发生过程中的腭架升高中发挥作用。该提案中概述的目标将进一步表征Pre蛋白缺陷胚胎中次级腭的畸形发生和相应的多功能蛋白聚糖水平。我们将研究与WT同窝仔相比，Prrx 1缺陷胚胎中腭间充质细胞行为的变化。最后，我们将确定在Prrx缺乏腭架改变的途径，开始阐明Prrx 1在继发性腭发育的遗传通路中的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Cleft palate is one of the most common craniofacial malformations in humans, impacting approximately 1 in 1000 live births. However the molecular mechanisms governing secondary palate formation prior to fusion are not well understood. We have recently discovered that mice deficient in the Prrx1 homeobox transcription factor display a cleft palate defect resulting from a lack of vertical palate elevation in 100% of homozygous offspring. This defect is more severe in Prrx1/Prrx2 double deficient embryos. Recently, a SNP study identified PRRX1 as a candidate gene in cleft palate birth defects. Therefore, our Prrx mutant mice are a relevant and novel mouse model that may facilitate uncovering the genetic circuitry involved in normal secondary palate and cleft formation. Our published and unpublished findings show that several extracellular matrix genes are direct downstream targets of Prrx1 and strongly expressed during secondary palate development. Our preliminary data demonstrates that Prrx1 binds specifically to the promoter of the proteoglycan versican, both in vitro and in vivo. Additionally our data shows that at early onset of dysmorphogenesis in the secondary palate of Prrx1 deficient mice, versican levels are dramatically increased in the palatal shelves compared to WT littermates. Since Prrx1 is strongly expressed in secondary palatal mesenchyme at E13.5 we hypothesize that Prrx1 directly regulates the expression of versican during secondary palate formation and plays a role in palatal shelf elevation during secondary palate morphogenesis. Aims outlined in the proposal will further characterize the dysmorphogenesis of the secondary palate in the Prrx deficient embryos and the corresponding levels of versican. We will examine the changes in cellular behavior of palatal mesenchyme in the Prrx1 deficient embryos compared to WT littermates. Finally we will determine the pathways altered in the Prrx deficient palatal shelves to begin to elucidate the role of Prrx1 in the genetic circuitry of secondary palate development.