MOLECULAR AND CELLULAR BASIS OF LENS DEVELOPMENT

胚胎发生是一个复杂的过程，在这个过程中， 多细胞成年生物在脊椎动物的胚胎中， 在决定细胞命运方面起主要作用。的 脊椎动物透镜提供了一个合适的模型系统来定义分子 参与决定细胞命运的机制，因为发育是由 一系列特定的组织相互作用透镜的区分涉及几个方面 阶段：能力、规范和决心。非洲爪蟾代表了 一个方便的，可操作的系统，其中研究透镜的发展，因为 这些阶段已经被时间定义，特定组织也是如此。 需要的互动。爪蟾幼虫的角膜 转分化为透镜。这一过程可以说反映了自然 透镜测定和鉴别中的事件。这代表了一个方便的 从该系统中分离涉及转分化的基因， 理论上在胚胎透镜形成的各个阶段。主要研究者有 创建了一个消减cDNA文库，富集了特异于 转分化该文库将被筛选出可能 参与转分化和透镜诱导， 它们在这些过程中的作用通过表达研究和功能测试。的 这些基因的表达模式将用于测试模型， 组织移植实验中的透镜诱导。最后，实验将 以鉴定在培养物中引起透镜形成的生长因子 角膜和胚胎外胚层组织。这两个因素都被怀疑在 基于现有的证据和新发现的从视网膜病变中分离出来的因素， 将检测cDNA文库。

Embryogeneis is a complex process whereby the fertilized egg gives rise to a multicellular adult organism. In vertebrate embryos, inductive interactions between specific tissues play a major role in determining cell fate. The vertebrate lens provides an appropriate model system to define the molecular mechanism involved in determining cell fate because development is triggered by a series of specific tissue interactions. Lens differentiation involves several stages: competence, specification and determination. Xenopus laevis represents a convenient, manipulatable system in which to study lens development because these stages have been temporally defined, as have the specific tissue interactions that are required. In Xenopus, the larval cornea can undergo transdifferentiation into lens. This process arguably reflects the natural events in lens determination and differentiation. This represents a convenient system from which to isolate genes involved in transdifferentiation and, theoretically in the various stages of embryonic lens formation. The PI has created a subtracted cDNA library enriched for genes that are specific to transdifferentiation. The library will be screened for genes potentially involved in transdifferentiation and lens induction and candidates assessed for their roles in these processes by expression studies and functional tests. The expression patterns of a number of these genes will be used to test models of lens induction in tissue transplantation experiments. Finally, experiments will be performed to identify growth factors that elicit lens formation in cultures of cornea and embryonic ectoderm tissue. Both factors suspected to play a role based on existing evidence and newly identified factors isolated from a retinal cDNA library will be tested.