Dix Genes in Neurogenic Cranial Placode Induction

描述（由申请人提供）：本申请的目的是研究 Dlx基因在神经源性颅基板诱导中的作用。神经源性 颅基板是增厚的外胚层的离散区域， 神经板前缘的早期发育。这些基板 会产生嗅觉器官中的大部分感觉和神经组织 系统、内耳和颅感觉神经节。的分子机制 这些基板诱导的根本原因尚不清楚。许多意见 表明外胚层注定要产生神经源性颅基板 在特异性基板诱导之前获得一般基板能力， 尽管没有直接证据表明这种国家存在或必要。一 许多基因，包括Dlx 5和Dlx 6，以一种模式表达，标志着 前基板外胚层，然而，他们的作用基板诱导还没有 仔细检查。我们假设神经源性颅基板不会 除非前神经板边缘的外胚层 产生这些基板获得一般基板能力。我们进一步 假设Dlx 5和/或Dlx 6是产生这种状态所必需 一般基板的能力，因此是必要的诱导所有 神经原性颅基板具体目标1：测试Dlx 5的必要性 和/或Dlx 6用于神经源性颅基板诱导，我们将使用显性- Dlx 5和Dlx 6在鸡胚前基板外胚层中呈阴性表达 以局部抑制内源性Dlx 5和Dlx 6活性。对以后的影响 基板诱导将决定Dlx 5和/或Dlx 6对此的必要性。 处理并澄清是否存在一般基板能力状态 在神经原性基板诱导之前。具体目标2：测试是否充分 Dlx 5和Dlx 6诱导未定向的基板能力的状态， 外胚层，我们将测试未定向的外胚层组织转染 与Dlx 5和Dlx 6一起在体外对特定的基板诱导组织产生反应。的 共培养后上胚层中特异性基板标志物的表达将 建立Dlx 5和/或Dlx 6诱导全身基板的充分性 外胚层的能力不受任何特定组织命运的影响。

DESCRIPTION (provided by applicant): The aim of this application is to study the role of Dlx genes in neurogenic cranial placode induction. The neurogenic cranial placodes are discrete regions of thickened ectoderm that are visible in early development at the anterior border of the neural plate. These placodes will give rise to the majority of sensory and neural tissue in the olfactory system, the inner ear, and the cranial sensory ganglia. The molecular mechanisms underlying the induction of these placodes are not known. Numerous observations suggest that the ectoderm fated to produce the neurogenic cranial placodes acquires general placode competence prior to specific placode induction, although there is no direct evidence that such a state exists or is necessary. A number of genes, including Dlx5 and Dlx6, are expressed in a pattern marking the pre-placodal ectoderm, however their roles in placode induction have not been carefully examined. We hypothesize that the neurogenic cranial placodes will not be properly induced unless the ectoderm at the anterior neural plate border giving rise to these placodes acquires general placode competence. We further hypothesize that Dlx5 and/or Dlx6 are necessary for the generation of this state of general placode competence, thus being necessary for the induction of all neurogenic cranial placodes. SPECIFIC AIM 1: To test the necessity of Dlx5 and/or Dlx6 for neurogenic cranial placode induction, we will use dominant- negative Dlx5 and Dlx6 expression in the pre-placodal ectoderm of chick embryos to locally inhibit endogenous Dlx5 and Dlx6 activity. Effects on subsequent placode induction will determine the necessity of Dlx5 and/or Dlx6 for this process and clarify whether or not a state of general placode competence precedes neurogenic placode induction. SPECIFIC AIM 2: To test the sufficiency of Dlx5 and Dlx6 to induce a state of placode competence in uncommitted ectoderm, we will test the ability of uncommitted epiblast tissue transfected with Dlx5 and Dlx6 to respond in vitro to specific placode-inducing tissues. The expression of specific placodal markers in epiblast following co-culture will establish the sufficiency of Dlx5 and/or Dlx6 to induce general placode competence in ectoderm uncommitted to any specific tissue fate.