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。这方面的第一个例子是在100多年前脊椎动物透镜发育的背景下证明的。随后，眼睛/透镜作为一个模型系统，用于理解的一般性质的诱导相互作用，由于其访问直接的实验操作，特别是在两栖动物胚胎。虽然我们对透镜诱导中的组织相互作用有很多了解，但我们才刚刚开始破译控制透镜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。在某些生物体中，晶状体可以通过其他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，当原始透镜被移除时，角膜上皮可以经历转分化以形成新的透镜。我们利用这个过程作为一个方便的分离基因参与透镜的形成。从消减cDNA文库中回收了大量基因，富集了角膜-晶状体转分化过程中表达的基因。初步研究表明，这些基因中的许多也在胚胎透镜发育过程中表达。将采用机器人原位杂交的高通量方法来表征这些基因在透镜发育和再生过程中的表达。这些数据将提供这两个透镜形成过程之间的分子关系的理解。在这些基因中有许多转录调节因子和细胞信号传导因子，它们可能在控制透镜发育和再生过程中起关键作用。我们将检查这些基因的功能，使用特定的检测，包括：在体内功能丧失和功能获得的分析。这些功能研究将与表达分析结合进行，以解读透镜形成的分子途径。最后，将通过组织移植和外植体培养实验，在当前透镜诱导模型的背景下检查基因表达和功能。对透镜发育和再生以及控制透镜细胞决定和分化的基因之间的分子和细胞关系的理解将最终导致治疗损伤和患病晶状体的新治疗方法的开发。

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.