Genetic and Morphometric Analysis of Facial Clefts

描述(申请人提供)：唇裂(CL)或唇腭裂(CL/P)发生在700名活产儿中，虽然它们是可以治疗的，但许多患有这类畸形的人将需要终身护理。这两种情况都是由于胚胎发育过程中面部隆起融合失败所致。CL和CL/P可作为单个畸形或作为综合征的一部分出现。例如，Branchio-Occulo-Face综合征(BofS)表现为面部分裂、耳朵和眼睛畸形，并与编码转录因子AP-2的基因TFAP2A的突变有关。这种疾病的一种小鼠模型使用零等位基因与AP-2？的亚型或“弱”等位基因相结合，造成AP-2？功能的部分丧失。这些小鼠出现了完全穿透的双侧CL/P，我们的初步数据表明，面部隆起的生长和/或形态发生的微小变化是导致融合失败的原因。对该模型的分子分析表明，涉及成纤维细胞生长因子信号转导的基因表达增加。此外，这些小鼠中单个Fgf8等位基因的丢失能够 AP-2？低形体小鼠的双侧CL/P部分恢复为单侧CL/P，因此假设AP-2？和FGF8是正常面部发育过程中相同途径的元件，AP-2？的缺失或突变会影响面部发育所需的信号交互作用。我们将通过检测面部外胚层过度表达FGF8的小鼠模型的形状、基因表达和功能来检验这一假设，并将该模型与我们的AP-2模型进行比较。这项提议将使用3D成像和形态测量来生成形状数据。有了这些数据，我们将能够比较FGF8过表达模型和AP-2亚型突变模型之间的形状，并确定这两个基因在发育过程中是否以相同的方式影响发育。基因表达数据将使我们能够1)将形状变化与基因表达、细胞增殖和死亡变化相关联，从而识别可能导致生长变化的途径和机制。2)表达数据将允许在分子水平上比较这两个模型，以确定它们是否影响相同的下游靶点，从而在相同的途径中发挥作用。基于这些数据，我们希望能够建立起这一途径是如何与其他已建立的面部发育途径相互作用的，以确定面部发育的整体面部基因调控网络。

DESCRIPTION (provided by applicant): Cleft lip (CL) or Cleft lip/palate (CL/P) occurs in about 1 in 700 live births, and while they are treatable, many individuals with these types of deformities will require lifelong care. Both of these conditions are the result of failures of the facial prominences to fuse during embryogenesis. CL and CL/P can occur as a single deformity or as part of a syndrome. Branchio-Occulo-Facial Syndrome (BOFS), for example, presents with facial clefting, ear and eye deformities and has been linked to mutations in the gene TFAP2A, encoding transcription factor AP-2¿. One mouse model of this disease employs a null allele in combination with a hypomorphic or "weak" allele of AP-2¿, creating a partial loss of AP-2¿ function. These mice develop a fully penetrant bilateral CL/P and our preliminary data suggest that it is small changes in growth and/or morphogenesis of the facial prominences that are responsible for failed fusion. Molecular analysis of this model shows increased expression of genes involved in Fgf signaling. Further, the loss of a single fgf8 allele in these mice is able to partially rescue the bilateral CL/P seen in the AP-2¿ hypomorphic mice to a unilateral CL/P. I, therefore hypothesize that AP-2¿ and FGF8 are elements of the same pathway during normal facial development and loss or mutation of AP-2¿ can affect the signaling interactions required for facial development. We will test this hypothesis by examining shape, gene expression and function in a mouse model that overexpresses FGF8 in the facial ectoderm and comparing this model to our AP-2 model. This proposal will generate shape data using 3D imaging and morphometrics. With this data we will be able to compare shape between the FGF8 overexpression model to the AP-2¿ hypomorphic mutation model and determine if these two genes are affecting development in the same manner during development. The gene expression data will allow us to 1) correlate shape change with gene expression, cell proliferation and death changes, allowing identification of pathways and mechanisms that may be causative of the growth changes. 2) The expression data will allow comparison of the two models on a molecular level to determine if they are affecting the same downstream targets, and thus, acting within the same pathway. Based on this data, we hope be able to build out how this pathway is interacting with other established facial development pathways to determine the overall facial gene regulatory network for facial development.