The Role of IRF6 During Craniofacial Development

描述(申请人提供)：孤立性唇腭裂是一种常见的先天性疾病，病因复杂。这项研究的目的是确定对腭部形成至关重要的基因的功能。干扰素调节因子6(IRF6)的基因变异会导致范德伍德综合征(VWS)，并导致12%的孤立性唇腭裂风险。包含IRF6的途径及其在协调腭部发育中的细胞作用尚不清楚。IRF6基因缺失的小鼠会出现腭裂、小颌畸形和口腔粘连。缺乏FgflO或TBX1的小鼠会出现腭裂和口腔粘连。人类Tbx，1，FgflO和Fgf8基因突变会导致唇腭裂。我们实验室的初步数据表明，FgflO在腭间充质中的表达和Fgf8在腭部上皮中的表达可能是Irf6激活的下游靶点。此外，颅面区域的IRF6可能调节了TBX1在腭部的表达。因此，我们假设IRF6既以细胞自主的方式调节上皮细胞分化，又以非细胞自主的方式影响间充质分化，这些功能部分通过成纤维细胞生长因子信号转导通路和TBX1介导。我们建议建立IRF6在腭裂发生和上皮-间充质信号中的作用。我们将在体内和使用体外腭部培养物评估IrfSA-腭架上的细胞凋亡和增殖。嵌合小鼠将被用来确定IRF6信号是否以细胞自主的方式存在。为了确定Irf6在腭部间充质发育中的作用，我们将使用神经脊和非神经脊特异的ERE小鼠系。在目标2中，我们将确定FgflO是否是腭部发育过程中Irf6信号的下游靶点。我们将评估Irf6和FgflO缺失小鼠中Irf6和FgflO表达的变化，并通过创造双Fgf10/lrf6杂合子小鼠来测试是否存在直接的遗传交互作用。在目标3中，我们将确定负责IRF6信号从上皮到间充质的基因(S)。我们将研究Tbx1和Fgf8在lrf6--小鼠体内的表达变化。为了测试是否存在直接的遗传交互作用，我们将创建双杂合Irf6/Tbx1和Irf6/Fgf8小鼠。本研究的目的是了解包括IRF6在内的信号通路，以及该通路中的缺陷是如何导致唇腭裂的。我们将利用这些信息来检查人类唇腭裂患者中潜在的基因-基因相互作用。

DESCRIPTION (provided by applicant): Isolated cleft lip and palate is a common congenital problem with a complex etiology. The objective of this research is to identify the function of genes critical to palatal formation. Genetic variation in Interferon Regulatory Factor 6 (IRF6) causes Van der Woude syndrome (VWS) and contributes 12% risk of isolated cleft lip and palate. The pathway containing Irf6 and its cellular role in orchestrating palatal development is not known. Mice deficient for Irf6 have cleft palate, micrognathia and oral adhesions. Mice deficient for either FgflO or Tbx1 have cleft palate and oral adhesions. Mutations in Tbx,1, FgflO, and Fgf8 in humans cause cleft lip and palate. Preliminary data from our laboratory suggests that FgflO expression in the palatal mesenchyme and Fgf8 expression in the palatal epithelium may be downstream targets for Irf6 activation. Furthermore, Irf6 in the craniofacial region may modulate expression of Tbx1 in the palate. Thus, we hypothesize that Irf6 functions in both a cell-autonomous manner to regulate epithelial differentiation and in a non-cell autonomous manner affecting mesenchymal differentiation and these functions are mediated in part through the Fgf signal transduction pathway and Tbx1. We propose to establish the role of Irf6 in palatogenesis and epithelial-mesenchymal signaling. We will evaluate apoptosis and proliferation in IrfSA- palatal shelves in-vivo and using in-vitro palatal cultures. Chimeric mice will be used to determine if Irf6 signals in a cell-autonomous fashion. To identify the role of Irf6 in palatal mesenchyme development we will use neural crest and non-neural crest specific ere mouse lines. In Aim 2 we will determine if FgflO is a downstream target of Irf6 signaling during palatal growth. We will evaluate changes in Irf6 and FgflO expression in Irf6 and FgflO null mice and test if there is a direct genetic interaction by creating double Fgf10/lrf6 heterozygous mice. In Aim 3 we will identify the gene(s) responsible for Irf6 signaling from the epithelium to the mesenchyme. We will investigate changes in expression of Tbx1 and Fgf8 in lrf6-\- mice. To test whether there is a direct genetic interaction, we will create double heterozygous Irf6/Tbx1 and Irf6/Fgf8 mice. The goal of this research is to understand the signaling pathway that includes IRF6, and how defects in this pathway lead to cleft lip and palate. We will use this information to examine potential gene-gene interactions in human cleft lip and palate patients.