Elucidating the function of the CHD gene, RAPGEF5, in Wnt signaling

项目总结/摘要 先天性心脏病是婴儿死亡和发病的主要原因之一， 在美国每1000个新生儿中。尽管这种巨大的健康影响，这种疾病的遗传原因不是 很好理解。为了更好地了解冠心病，我们沿着其他实验室，正在分析 冠心病患者。特别是，我们检查了异位，一种左右（LR）模式紊乱，可导致 由于心脏循环失败而导致的严重心脏畸形。通过这种遗传学方法，我们发现 RAPGEF 5作为一个新的异位症和先天性心脏病候选基因，其编码一个鸟嘌呤 激活RAP GT3的核苷酸交换因子。然后我们模拟了这种心血管疾病， 通过消耗Rapgef 5，它重现了人类异位表型，并证明， rapgef 5通过调节Wnt信号通路中β-catenin的核进入来影响心脏循环。的主要目标 本研究的目的是探讨rapgef 5调控细胞核转录的分子机制。 β-catenin的定位。值得注意的是，β-连环蛋白核转位的机制仍然是一个悬而未决的问题。 Wnt信号传导中的问题，这对发育生物学和癌症有影响。 在这个建议中，我有两个具体的目标，基于以下假设： 假设：Rapgef 5维持核Rap蛋白处于活性GTP结合状态，其将优先 将β-catenin导入细胞核 目的1：体外β-catenin核质穿梭动力学分析 目的2：鉴定一个介导β-连环蛋白核转运系统的RAP GT3 总之，这些实验将提高我们对心脏发育和rapgef 5作用的理解。 在CHD发病机制中的作用以及其在Wnt信号传导中的作用。在未来，这将有利于基因检测， 咨询，以及改善冠心病的结果，因为治疗可以针对基因型而不是 仅对CHD表型有影响。此外，此应用程序详细说明了我的培训计划，包括研究 导师制、高级课程、新技术培训以及科学技能的发展。 专业性、写作和数据展示。本申请中概述的研究和培训将 准备我追求的职业生涯执行病人驱动的研究作为一个独立的医生，科学家。

Project Summary/ Abstract Congenital heart disease (CHD) is one of the leading causes of infant mortality and morbidity affecting 8 out of every 1000 newborns in the US. Despite this massive health impact, the genetic causes of this disease are not well understood. In order to better understand CHD, we, along with other labs, are analyzing the genomics of CHD patients. In particular, we examined heterotaxy, a disorder of left-right (LR) patterning that can lead to severe form of cardiac malformation due to failure of cardiac looping. From this genetic approach, we identified RAPGEF5 as a novel candidate gene for heterotaxy and congenital heart disease, which encodes a guanine nucleotide exchange factor that activates RAP GTPase(s). We then modeled this cardiovascular disease in Xenopus by depleting Rapgef5, which recapitulated the human heterotaxy phenotype and demonstrated that rapgef5 affects cardiac looping via regulating the nuclear entry of β-catenin in Wnt signaling. The main goal of this proposal is to investigate the molecular mechanism by which rapgef5 controls the nuclear localization of β-catenin. Of note, the mechanism of β-catenin nuclear translocation remains an outstanding question in Wnt signaling, that has implications for developmental biology and cancer. In this proposal, I have two specific aims based on the following hypothesis: Hypothesis: Rapgef5 maintains nuclear Rap protein(s) in an active GTP bound state, which will preferentially import β-catenin into the nucleus Aim 1: Kinetic analysis of β-catenin nucleocytoplasmic shuttling in vitro Aim 2: Identify a RAP GTPase that mediates the β-catenin nuclear transport system Altogether, these experiments will improve our understanding of cardiac development and the role of rapgef5 in the pathogenesis of CHD as well as its role in Wnt signaling. In the future, this will benefit genetic testing and counseling, as well as improve outcomes in CHD because treatments can be tailored to genotype rather than solely on CHD phenotype. In addition, this application details the my training plan including research mentorship, advanced coursework, training in new techniques, and the development of skills in scientific professionalism, writing, and presentation of data. The research and training outlined in this application will prepare me to pursue a career performing patient-driven research as an independent physician-scientist.