MOLECULAR AND CELLULAR BASIS OF LENS DEVELOPMENT

决定特定细胞命运的过程包括 胚胎发生的基本方面。在脊椎动物胚胎中，特定的 组织相互作用，称为诱导相互作用，在 对各种细胞命运的测定。我们的总目标是 研究这些过程的分子和细胞基础。 脊椎动物晶状体的开发已经被证明是一个很好的系统，在这个系统中 来研究这些事件，因为这个器官的发育是由 通过一系列特定的组织相互作用。这个系统的成功 在一定程度上是因为它可以直接进行实验 操纵，特别是在两栖动物胚胎中。我们对此的理解 脊椎动物晶状体诱导中涉及的组织相互作用是 然而，人们对分子基础几乎一无所知。 用于确定晶状体细胞的过程，或信号分子 参与晶状体诱导。这些问题是会议的主要焦点。 目前的研究建议。我们将致力于确定 基因表达的特定变化与 晶状体细胞的测定和分化过程 非洲爪哇两栖动物。要分离出这些病毒是非常困难的 直接从微小的假定晶状体外胚层组织中提取基因 早期发展。在非洲爪哇，晶状体会从幼虫再生 晶状体摘除后的角膜是一个转分化的过程。在… 在一定程度上，这些基因在晶状体再生过程中表达 应该与胚胎发育过程中表达的基因相同 透镜形成。晶状体再生的现象，将被用作 一种更方便的方法来分离参与过程的基因 晶状体细胞的测定和分化。将有两个cDNA库 由再生和非再生角膜制成。基因特异性 对晶状体再生过程的影响将使用该技术进行隔离 消减杂交的结果。一旦这些基因被分离出来，他们的 胚胎晶状体发育过程中的表达将被研究 编队，将进行具体测试，以确定 这些基因在这一过程中起着积极的作用。最后，这些基因 将被用作指示晶状体发育早期阶段的标记 组织培养实验检测特定晶状体的作用 诱导性相互作用在触发基因的特定变化中发挥作用 表情。此外，还将进行组织培养实验，以 解决以前的研究提出的问题，这些研究表明 神经脊细胞的抑制作用在精确定位中发挥作用 头外胚层中晶状体分化的确切位置。最后， 将进行实验以确定特定的生长 胚胎外胚层培养中诱导晶状体形成的因素 纸巾。越来越多的证据表明，增长因素在 胚胎细胞测定的各个方面。

Those processes involved in the determination of specific cell fates are fundamental aspects of embryogenesis. In vertebrate embryos, specific tissue interactions, termed inductive interactions, play a major role in the determination of various cell fates. The general goal of our research is to the molecular and cellular basis of these processes. Vertebrate lens development has proved to be an excellent system in which to examine these events, since the development of this organ is triggered by a series of specific tissue inter-actions. The success of this system is due, in part, to its accessibility to direct experimental manipulation, particularly in amphibian embryos. Our understanding of the tissue interactions involved in vertebrate lens induction is extensive, however, virtually nothing is known about the molecular basis for the process of lens cell determination, or the signal molecules involved in lens induction. These issues are the main focus of the current research proposal. Efforts will be devoted to identifying specific changes in gene expression which are associated with the processes of lens cell determination and differentiation using the amphibian Xenopus laevis. It would be very difficult to isolate these genes directly from minute presumptive lens ectodermal tissues during early development. In Xenopus, lenses will regenerate from the larval cornea following lens removal, a process of transdifferentiation. At some level, those genes expressed during the process of lens regeneration should be the same as those expressed during the process of embryonic lens formation. The phenomenon of lens regeneration, will be utilized as a more convenient means to isolate genes involved in the processes of lens cell determination and differentiation. Two cDNA libraries will be prepared from regenerating and non-regenerating corneas. Genes specific to the process of lens regeneration will be isolated using the technique of subtractive hybridization. Once these genes are isolated, their expression will be studied during the process of embryonic lens formation, and specific tests will be conducted to determine whether these genes play an active role in this process. Finally, these genes will be used as markers indicative of early stages of lens development in tissue culture experiments to examine the role that specific lens inductive interactions play in triggering specific changes in gene expression. In addition, tissue culture experiments will be conducted to address questions raised by previous studies, which suggest that inhibitory effects of neural crest cells play a role in pinpointing the exact site of lens differentiation in head ectoderm. Finally, experiments will be performed to determine whether specific growth factors can elicit lens formation in cultures of embryonic ectodermal tissues. There is growing evidence that growth factors play a role in various aspects of embryonic cell determination.