Molecular and Cellular Basis of Lens Development

描述：特定的组织相互作用，或“诱导相互作用”，控制所有脊椎动物器官系统的发育。第一个例子是在100多年前脊椎动物晶状体发育的背景下被证明的。随后，眼睛/晶状体被用作理解诱导相互作用的一般性质的模型系统，因为它易于直接实验操作，特别是在两栖动物胚胎中。尽管我们对晶状体诱导过程中涉及的组织相互作用了解甚多，但我们刚刚开始破译控制晶状体细胞决定和分化的分子事件。这项研究的目的是确定参与控制这些过程的基因。在一些生物体中，晶状体可以通过其他已分化的幼虫或成体细胞类型的转分化而再生。在非洲爪蟾中，当原晶状体被摘除时，角膜上皮可以发生转分化形成新的晶状体。我们已经利用这个过程作为一个方便的分离基因参与晶状体的形成。从一个缺失的cDNA文库中恢复了大量基因，这些基因在角膜-晶状体转分化过程中表达。初步研究表明，这些基因中的许多也在胚胎晶状体发育过程中表达。采用机器人原位杂交的高通量方法将用于表征晶状体发育和再生过程中这些基因的表达。这些数据将有助于理解这两种透镜形成过程之间的分子关系。这些基因中有许多转录调节因子和细胞信号因子，它们可能在控制晶状体发育和再生过程中发挥关键作用。我们将使用特定的分析方法来检查这些基因的功能，包括：体内功能丧失和功能获得分析。这些功能研究将与表达分析一起进行，以破译晶状体形成的分子途径。最后，将通过组织移植和外植体培养实验，在当前晶状体诱导模型的背景下检查基因表达和功能。了解晶状体发育和再生之间的分子和细胞关系，以及控制晶状体细胞决定和分化的基因，将最终导致治疗损伤和病变晶状体的新治疗方法的发展。

DESCRIPTION: Specific tissue interactions, or "inductive interactions," control the development of all vertebrate organ systems. The first example of this was demonstrated in the context of vertebrate lens development, over 100 years ago. Subsequently, the eye/lens has served as a model system for understanding the general nature of inductive interactions, due to its accessibility to direct experimental manipulation, particularly in amphibian embryos. Although a great deal is known about tissue interactions involved in lens induction, we have just begun to decipher molecular events that control lens cell determination and differentiation. The goal of this study is to identify genes involved in controlling these processes. In some organisms, lenses can regenerate via the transdifferentiation of other differentiated larval or adult cell types. In Xenopus, the cornea epithelium can undergo transdifferentiation to form a new lens when the original lens is removed. We have exploited this process as a convenient one to isolate genes involved in lens formation. A large suite of genes were recovered from a subtracted cDNA library, enriched for those expressed during the process of cornea-lens transdifferentiation. Preliminary studies indicate that many of these genes are also expressed during embryonic lens development. A high-throughput approach employing robotic in situ hybridization will be applied to characterize the expression of these genes during lens development and regeneration. This data will provide an understanding of the molecular relationships between these two lens-forming processes. A number of transcriptional regulators and cell signaling factors are represented amongst those genes, which are likely to play key roles in controlling the processes of lens development and regeneration. We will examine the functions of these genes using specific assays, including: in vivo loss-of-function and gain-of- function analyses. These functional studies will be performed in conjunction with expression analyses to decipher molecular pathways of lens formation. Finally, gene expression and function will be examined in the context of the current model of lens induction, via tissue transplantation and explant culture experiments. An understanding of molecular and cellular relationships between lens development and regeneration, and the genes controlling lens cell determination and differentiation, will ultimately lead to the development of new therapeutic approaches to treat injured and diseased lenses.