Novel Mechanism of Induction of Eye Tissue: Katp Channel Modulation

描述（由申请人提供）：重要的生物医学应用，以及基础生物学的进展，需要详细了解胚胎发育中的模式形成。在对比和补充目前的重点生化控制因素，我们的实验室旨在了解和学习操纵进化保守的内源性静态膜电压梯度和离子通量控制细胞的命运和形态发生。在胚胎发育中K+通量的作用的实验中，我们发现，特异性调节Katp通道（在代谢，糖尿病和心脏保护中具有关键作用的K+通道）的活性诱导青蛙胚胎异位眼组织。表型范围从孤立的视网膜组织和晶状体，到在许多异位位置（包括肠道和尾部）形成的完整眼睛。这是一个非常令人兴奋的发现，因为它1）确定了一种具有高度生物医学相关性的离子通道的新模式作用，2）揭示了一个分子切入点，进入眼睛发育的一个全新方面，可能导致对目前眼睛诱导模型的修订，以及3）提供了一种控制细胞命运的新方法（通过调节K+通量），其在治疗应用中的眼组织的生产中具有应用。我们建议通过在我们实验室的分子生物学，生物物理学和功能生理学技术在一些易于处理的模型系统，如非洲爪蟾，在这个重要的和高度新颖的领域取得突破。通过使用已建立的技术和试剂来测试关于异位眼诱导机制的分子假设的五个目标，我们将了解该事件与内源性眼形成途径的相互作用，确切地发现异位眼何时，何地以及如何诱导，确定异位眼是否有功能，这项工作与AED以及眼科和普通医学科学研究所的任务具有高度相关性，因为我们建议利用强大的技术，该模型动物在理解、预防和修复先天缺陷和视觉系统退行性疾病方面取得了广泛而重要的生物医学进展。

DESCRIPTION (provided by applicant): Important biomedical applications, as well as advances in basic biology, require a detailed understanding of pattern formation in embryonic development. In contrast and complement to the current focus on biochemical control factors, our lab seeks to understand and learn to manipulate evolutionarily-conserved endogenous static membrane voltage gradients and ion fluxes which control cell fate and morphogenesis. During experiments on the role of K+ fluxes in embryonic development, we discovered that specific modulation of the activity of Katp channels (K+ channels with crucial roles in metabolism, diabetes, and cardioprotection) induces ectopic eye tissue in frog embryos. The phenotypes range from isolated retina tissue and lenses, to complete eyes formed in many ectopic locations (including on the gut and tail). This is a very exciting finding because it 1) identifies a novel patterning role for an ion channel of high biomedical relevance, 2) reveals a molecular entrypoint into a completely novel aspect of eye development that may cause revisions of current models of eye induction, and 3) provides a new way to control cell fate (via modulation of K+ flux) in somatic cells, which has applications in the production of eye tissue in therapeutic applications. We propose to make breakthroughs in this important and highly novel area through a unique convergence in our lab of molecular biology, biophysics, and functional physiology techniques in a number of tractable model systems such as Xenopus laevis. Through five aims that use established techniques and reagents to test molecular hypotheses about the mechanisms of ectopic eye induction, we will understand the interaction of this event with the endogenous eye-forming pathways, discover exactly when, where, and how the ectopic eyes are induced, determine whether the ectopic eyes are functional, and identify novel genes linking Katp activity to the eye gene cascade.This work has high relevance to the AED and the missions of the Eye and General Medical Sciences Institutes because we propose to utilize powerful techniques in a tractable model animal to produce wide-reaching and important biomedical advances in understanding, preventing, and repairing birth defects and degenerative diseases of the visual system.