Redox-sensitive developmental pathways and gene regulatory networks

描述（由申请人提供）： 该项目的目标是阐明氧化还原反应的发育途径和基因调控网络，介导对环境氧化还原应激的易感性。氧化还原化学是生物学的核心，它提供了生命所需的能量，但也产生了活性氧（ROS）形式的有毒副产品。ROS的产生会导致氧化应激，这是许多人类疾病（如糖尿病）和环境诱导的病理（如与酒精滥用相关的疾病）的标志。因此，生物信号传导系统通常对氧化还原化学反应有响应。虽然许多环境氧化还原应激因素也已知会导致人类发育畸形，特别是在发育中的神经系统中，但介导这种易感性的氧化还原敏感性调节网络在很大程度上是未知的。海胆胚胎为解决这一问题提供了一个有用的比较模型，因为它的基因组已被测序和注释，并且因为它是后口动物，因此在发育上比其他无脊椎模式生物更类似于人类。许多研究结果表明，外胚层细胞的命运沿着的海胆胚胎的口-口轴指定通过氧化还原敏感的调节网络，并可以具体扰动（辐射）的氧化还原应激源，如金属离子和缺氧。外胚层细胞命运特化由Nodal信号传导介导，Nodal信号传导又依赖于p38丝裂原活化蛋白激酶（MARK）。本项目的具体目标是：（1）检验p38丝裂原活化蛋白激酶（MARK）活性受发育中外胚层氧化还原信号调节的假设;（2）鉴定调节Nodal活性的氧化还原应答顺式元件和转录因子;（3）鉴定氧化还原应激物干扰外胚层模式并影响人类发育和疾病的途径。为了实现这些目标，该项目将利用高度特异性的分子试剂，包括靶向酶促抗氧化剂，吗啉代反义介导的敲除，以及Nodal基因的顺式调控分析。此外，将使用微阵列方法来鉴定氧化还原敏感的转录组。最后，MDIBL的比较毒理基因组学数据库（CTD）将用于确定海胆中发现的途径与人类健康的相关性，并产生可能解释特定人类疾病的假设。

DESCRIPTION (provided by applicant): The goal of this project is to elucidate redox-responsive developmental pathways and gene regulatory networks that mediate susceptibility to environmental redox stressors. Redox chemistry is at the core of biology, providing the energy that fuels life but also producing toxic byproducts in the form of reactive oxygen species (ROS). ROS production can lead to oxidative stress, a hallmark of many human diseases (such as diabetes) and environmentally-induced pathologies (such as those associated with alcohol abuse). Biological signaling systems are therefore often responsive to redox chemistry. While many environmental redox stressors are also known to cause developmental malformations in humans, particularly in the developing nervous system, the redox-sensitive regulatory networks that mediate this susceptibility are largely unknown. The sea urchin embryo provides a useful comparative model for addressing this problem, as its genome has been sequenced and annotated, and because of the fact that it is a deuterostome and hence developmentally more similar to humans than other invertebrate model organisms. A number of findings indicate that ectodermal cell fate along the oral-aboral axis of the sea urchin embryo is specified via a redox-sensitive regulatory network, and can be specifically perturbed (radialized) by redox stressors such as metal ions and hypoxia. Ectodermal cell fate specification is mediated by Nodal signaling, which in turn is dependent on p38 mitogen activated protein kinase (MARK). The specific aims of this project are to (1) test the hypothesis that p38 mitogen activated protein kinase (MARK) activity is regulated by redox signaling in the developing ectoderm; (2) identify redox-responsive cis-elements and transcription factors that regulate Nodal activity; and (3) identify pathways through which redox stressors perturb ectodermal patterning and affect human development and disease. To achieve these aims, the project will make use of highly specific molecular reagents including mitochondrially-targeted enzymatic anti-oxidants, morpholino-antisense mediated knockdown, and cis-regulatory analysis of the Nodal gene. In addition, a microarray approach will be used to identify the redox-sensitive transcriptome. Finally, the Comparative Toxicogenomics Database (CTD) at MDIBL will be used to determine the relevance of the pathways discovered in sea urchins to human health, and to generate hypotheses that might explain specific human diseases.