Patterning of the optic vesicle by extrinsic factors

描述(申请人提供)：本项目的长期目标是 了解细胞和组织-组织之间的相互作用如何调节 中枢神经系统。组织-组织相互作用的中断可能会导致 影响大脑和眼睛的一系列严重的出生缺陷，例如 无前脑畸形、先天性无眼球、小眼球和无脑畸形。 了解正常的发展过程将允许更好地 预防和处理此类缺陷。有人建议研究一下， 参与这些相互作用的信号分子使用胚胎眼睛作为 一个前脑发育的模型系统，其中相同的机制最 可能会规范地区性规范。经典的胚胎学研究已经 表明眼外组织是正常眼睛生长所必需的， 差异化。目前关于这些信号的信息很少。 参与了这些互动。大鼠视小泡外植体培养 鸡胚胎，摘除眼外间充质严重干扰 视网膜色素上皮(RPE)的形成。TGFbeta家族 成员激活素已经被证明是一个候选信号，它准确地模拟了 眼外间充质对视网膜色素上皮体外发育的影响。 建议用来检验激活素信号通路是否 鸡胚眼RPE形成所必需的(目标1)。干涉 随着激活素信号通路在RPE的发展，可溶性激活素型 将应用II受体以及异位表达的拮抗剂 Smads(Smad6，7)和截短的激活素II受体 电穿孔。将确定激活素或相关信号是 由眼外间充质细胞产生(目标2)。自颅骨间充质 含有RPE发育的诱导剂，足够量的这种组织可以 因退化的聚合酶链式反应策略而被隔离。随后，识别出的 将克隆分子并检测外植体中RPE的促进活性 通过培养和转基因鸡胚胎。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand how cellular and tissue-tissue interactions regulate development of the central nervous system. Disruption of tissue-tissue interactions can lead to a wide range of serious birth defects affecting the brain and eye, such as holoprosencephaly, congenital anophthalmia, microphthalmia, and anencephaly. Understanding the normal process of development will allow for better prevention and treatment of such defects. It is proposed to study the role of signaling molecules involved in these interactions using the embryonic eye as a model system for forebrain development, where the same mechanisms most likely regulate regional specification. Classical embryological studies have shown that the extraocular tissues are required for normal eye growth and differentiation. At present there is little information about the signals involved in these interactions. In explant cultures of optic vesicles from chick embryos, removal of the extraocular mesenchyme severely interferes with the formation of the retinal pigmented epithelium (RPE). The TGFbeta family member activin has been shown to be a candidate signal that exactly mimics the effects of the extraocular mesenchyme on RPE development in vitro. It is proposed to test the hypothesis whether the activin signaling pathway is required for RPE formation in the chick embryonic eye (Aim 1). To interfere with the activin signaling pathway in the developing RPE, soluble activin type II receptors will be applied as well as ectopic expression of antagonistic Smads (Smad6, 7) and truncated activin type II receptors using electroporation. It will be determined whether activin or a related signal is produced by the extraocular mesenchyme (Aim 2). Since cranial mesenchyme contains the inducer of RPE development, sufficient amounts of this tissue can be isolated for a degenerate PCR strategy. Subsequently, the identified molecule will be cloned and tested for the RPE-promoting activity in explant cultures and by transfection of chick embryos.