Plasticity in an embryonic gene regulatory network

胚胎基因调控网络的可塑性

• 批准号: 9221354
• 负责人: Joel H. Rothman
• 金额: $ 29.91万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA BARBARA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9221354
• 关键词: Accounting; Adopted; Animals; Anterior; Architecture; Behavioral Genetics; Biological; Caenorhabditis elegans; Cells; Chromatin; Complex; Daughter; Dependence; Development; Diffuse; Dissection; Embryo; Embryonic Development; Endoderm; Ensure; Genes; Genetic; Genetic Variation; Genome; Genomics; Genotype; Germ Layers; Goals; Haplotypes; Human; Inbreeding; Individual; Lead; Ligands; MAP Kinase Gene; Memory; Methods; Molecular; Molecular Genetics; Organ; Output; Pathway interactions; Pattern; Persons; Pharmacology; Physical condensation; Predisposition; Process; Quantitative Trait Loci; RNA interference screen; Recombinants; Regenerative Medicine; Regulation; Regulator Genes; Reproducibility; Research; Role; Signal Transduction; Specificity; Stem cells; System; Testing; Time; Tissues; Variant; WNT Signaling Pathway; blastomere structure; body system; cell type; developmental plasticity; embryo cell; functional genomics; gene function; genetic makeup; genome wide association study; genome-wide; network architecture; notch protein; novel; personalized medicine; prevent; programs; public health relevance; response; tool; transcription factor; zygote

 DESCRIPTION (provided by applicant): The major objectives of the proposed research are to reveal the mechanisms by which gene regulatory network (GRN) architecture ensures a constant output in response to genetic variation and to mechanistically dissect the processes that convert embryonic cells from multipotentiality to a committed state of differentiation. The well-described GRN that directs specification and differentiation of the endoderm during C. elegans embryogenesis will be used to investigate these problems. This GRN is initiated by the combined action of a maternal transcription factor, SKN-1, and a triply redundant Wnt, MAPK, and src signaling system. Analysis of 97 C. elegans wild isolates (isotypes), each with a unique haplotype, revealed dramatic variation in requirements for SKN-1 and MOM-2/Wnt in endoderm formation, allowing comprehensive dissection of genomic changes in GRN action. Further, we found that a novel Notch signaling system establishes a memory state in the early embryo that activates the embryonic multipotentiality ¿ commitment transition (MCT) and prevents cells from being reprogrammed by components of the endoderm GRN later in development. We will build on these preliminary findings to reveal mechanisms of genetic and developmental plasticity in the endoderm GRN through three specific aims. In Aim 1, we will characterize the molecular and genetic basis for broad variation seen among the C. elegans isotypes in the requirement for SKN-1 and Wnt signaling by identifying the relevant loci and their interactions via genome-wide association studies and QTL analysis. We will quantify expression differences in components of the endoderm GRN in selected strains with the goal of understanding how the genotypic changes alter flux, and allow for plasticity, in the network. In Aim 2, we will investigate the acton of the Notch signaling system and two novel secreted Notch ligands, DSL-1 and -3, in regulation of developmental plasticity and the timing of onset of the MCT. We will evaluate the hypotheses that this signaling system functions autonomously within the lineage of the major ectoblast, the AB cell, to regulate the MCT by the action of diffusible secreted molecules and that it acts on the MCT by regulating chromatin condensation. In Aim 3, we will perform RNAi-based screens to identify the comprehensive set of genes required for regulating developmental plasticity during embryogenesis. We will analyze the lineage, regional, and temporal specificity of genes required for timely execution of the MCT, assess the breadth of action of the genes in preventing alternative programs of cell type differentiation, and evaluate the molecular pathways through which the genes function. Findings from this research may lead to a better understanding of the processes required to generate new replacement tissues and organs in regenerative medicine. They will also serve as a paradigm for understanding the relationship between an individual's genotype and their responsiveness to pharmacological agents, thereby contributing to advances in personalized medicine.

 描述（由申请人提供）：拟议研究的主要目标是揭示基因调控网络（GRN）架构确保响应遗传变异的恒定输出的机制，并机械地剖析胚胎细胞从多能性转变为多能性的过程。明确描述的GRN在秀丽隐杆线虫胚胎发生过程中指导内胚层的规范和分化，该GRN是由a的联合作用引发的。母体转录因子 SKN-1 以及三重冗余 Wnt、MAPK 和 src 信号系统 对 97 种秀丽隐杆线虫野生分离株（同种型）（每种都具有独特的单倍型）的分析揭示了对 SKN-1 和 MOM 的需求的巨大差异。 -2/Wnt 在内胚层形成中，允许全面剖析 GRN 作用中的基因组变化。此外，我们发现一种新的 Notch 信号系统在早期胚胎中建立了一种激活的记忆状态。胚胎多潜能我们将在这些初步发现的基础上，通过三个具体目标揭示内胚层 GRN 的遗传和发育可塑性机制。将通过全基因组关联研究和 QTL 识别相关基因座及其相互作用，来表征线虫同种型之间对 SKN-1 和 Wnt 信号传导的需求的广泛变异的分子和遗传基础我们将量化选定菌株中内胚层 GRN 成分的表达差异，目的是了解基因型变化如何改变网络中的通量并实现可塑性。在目标 2 中，我们将研究 Notch 信号传导的作用。我们将评估该信号系统在主要谱系内自主发挥作用的假设。外胚层（AB 细胞）通过可扩散分泌分子的作用调节 MCT，并作用于 通过调节染色质凝集进行 MCT 在目标 3 中，我们将进行基于 RNAi 的筛选，以确定胚胎发生过程中调节发育可塑性所需的全套基因。 MCT，评估基因在阻止细胞类型分化的替代程序中的作用广度，并评估基因发挥作用的分子途径。这项研究的结果可能有助于更好地理解产生新的替代程序所需的过程。它们还将作为理解个体基因型与其对药物的反应之间关系的范例，从而促进个性化医疗的进步。