Novel Mechanism of Induction of Eye Tissue: Katp Channel Modulation

描述(申请人提供)：重要的生物医学应用，以及基础生物学的进步，需要对胚胎发育中的模式形成有详细的了解。与目前对生化控制因素的关注形成对比和补充的是，我们的实验室试图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，这些电压梯度和离子通量控制细胞的命运和形态发生。在研究钾通道在胚胎发育中的作用的实验中，我们发现KATP通道(在新陈代谢、糖尿病和心脏保护中起关键作用的钾通道)活性的特异性调节导致了青蛙胚胎异位眼组织的形成。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(包括肠道和尾巴)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)揭示了眼睛发育的一个全新方面的分子入口点，这可能导致对当前眼睛诱导模型的修订，3)提供了一种控制体细胞命运的新方法(通过调节K流量)，这在治疗应用中应用于眼组织的生产。我们计划通过在我们的实验室中将分子生物学、生物物理学和功能生理学技术在一些易处理的模型系统(如非洲爪哇)中进行独特的融合，在这一重要且非常新颖的领域取得突破。通过利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说，我们将了解这一事件与内源性眼球形成途径的相互作用，准确地发现异位眼被诱导的时间、地点和方式，确定异位眼是否具有功能，并识别将KATP活性与眼基因级联联系起来的新基因。这项工作与AED以及眼科和普通医学研究所的任务高度相关，因为我们提议在易驯服的模型动物中利用强大的技术来在理解、预防和修复视觉系统的出生缺陷和退行性疾病方面取得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.