Gene regulatory network evolution and the origin of biological novelties

描述（由申请人提供）：细胞在发育期间通过组合基因活性的差异途径获得其独特的命运。控制内中胚层细胞命运的基因调控网络（GRN）已经在一些模型系统中构建，包括海胆、脊椎动物和线虫。产生内胚层（肠衍生物）和中胚层（肌肉、血液、体腔、肾和骨骼成分）细胞类型的内胚层前体通过差异基因表达而与外胚层前体（产生表皮和神经系统）不同。随后从内中胚层前体中指定单独的内胚层和中胚层命运。了解细胞内因子和细胞外信号之间的关系，以及重建不同动物物种之间的基因调控网络，可以为每个生物体的分子和形态特征如何以及何时建立提供关键见解。一个最好的例子是在动物进化中胚层的原始进化外观。刺胞动物（海葵、珊瑚和“水母”）是一个动物群体，其成年动物仅具有两个胚层的衍生物，外胚层和双功能（具有吸收和收缩功能）胃胚层（肠道）层。刺胞动物是其他两侧对称动物的近亲，拥有所有三个胚层，令人信服的分子，基因组，发育和进化的证据表明，刺胞动物的胃是所有其他三胚层两侧动物的内胚层和中胚层胚层的进化前体。因此，解开这个刺胞动物的“endomesodermal”基因调控网络，将提供必要的洞察如何GRN子电路已被采用，重新布线或增选在各种后生动物，以产生新的，修改或专门的endomesodermal功能。这项资助将在功能上重建刺胞动物海葵Nematostella vectensis（其基因组已由J.G.I（部门）测序）中内中胚层形成的基因调控网络。能量），使用，QPCR，全基因组微阵列，功能技术如药物治疗，合成mRNA错误表达，翻译和剪接阻断吗啉代方法和顺式调节分析。此外，我们将把所有获得的数据纳入现有的基因表达数据库，以便与科学界分享我们的发现。第一次从遗传学上关键的物种中产生高质量的分子数据，将有助于解释先前在双侧模型系统中通过极化进化变化的方向而确定的基因及其调控相互作用中的差异。 公共卫生相关性：在发育中的动物胚胎中，单个细胞通过每个细胞基因组中包含的特定基因的顺序差异激活来了解它们的最终命运。我们已经了解了很多关于这些基因在复杂的基因调控网络（GRN）中如何在功能上相互调控的信息。这项资助使用了一个强大的新模型系统来从功能上理解内胚层（肠道）和中胚层（例如肌肉，血液，骨骼，肾脏）是如何从一个共同的内中胚层前体中产生的。这些新的数据将提供深入了解的意义，在不同的系统中的GRNs的变化，并建议特定的基因相互作用参与异常内中胚层发育。

DESCRIPTION (provided by applicant): Cells acquire their unique fates by the differential pathways of combinatorial gene activity during the developmental period. Gene regulatory networks (GRN) controlling the specification of endomesodermal cell fates have been constructed in a handful of model systems, include sea urchins, vertebrates, and nematodes. Endomesodermal precursors that give rise to endodermal (gut derivatives) and mesodermal (muscle, blood, coelom, kidney and skeletal elements) cell types become distinct from ectodermal precursors (that give rise to epidermis and nervous system) by differential gene expression. Separate endodermal and mesodermal fates are then specified subsequently from endomesodermal precursors. Understanding the relationship between intracellular factors and extracellular signals, and reconstructing gene regulatory networks between different animal species can provide key insights in how and when the molecular and morphological characters of each organism are built. A prime example is the original evolutionary appearance of the mesodermal germ layer in animal evolution. Cnidarians (anemones, corals, and "jellyfish") are an animal group whose adults possess derivatives of only two germ layers, ectoderm and a bifunctional (having both absorptive and contractile functions) gastodermal (gut) layer. Cnidarians are the closest living relatives of other bilaterally symmetrical animals that possess all three germ layers, and compelling molecular, genomic, developmental, and evolutionary evidence exists to demonstrate that the cnidarian gastrodermis is the evolutionary precursor of both endodermal and mesodermal germ layers in all other triploblastic bilaterian animals. Thus, unraveling this cnidarian "endomesodermal" gene regulatory network, will provide necessary insight into how GRN sub circuits have been adopted, rewired or co-opted in various metazoan in order to give rise to novel, modified or specialized endomesodermal features. This grant will functionally reconstruct the gene regulatory network underlying endomesoderm formation in the cnidarian sea anemone Nematostella vectensis, (whose genome has been sequenced by the J.G.I (Dept. Energy), using, QPCR, whole genome microarrays, functional techniques such as pharmaceutical drug treatments, synthetic mRNA misexpression, translation and splice blocking morpholino approaches and cis-regulatory analysis. In addition, we will implement all the obtained data into an already existing gene expression database in order to share our findings with the scientific community. The generation of high quality molecular data from a phylogentically pivotal species for the first time will help explain the differences seen in genes and their regulatory interactions previously identified in bilaterian model systems by polarizing the direction of evolutionary change. PUBLIC HEALTH RELEVANCE: Project Narrative Individual cells in developing animal embryos learn their ultimate fate by the sequential differential activation of specific genes contained in each cell's genome. We have learned a great deal about how these genes functionally regulate each other in complex gene regulatory networks (GRN) in a handful of model species. This grant uses a powerful new model system to functionally understand how endodermal (gut) and mesodermal (e.g. muscle, blood, bone, kidney) arose from a common endomesodermal precursor. These novel data will provide insight into the significance of variations in the GRNs in different systems and suggest specific gene interactions involved in abnormalities in endomesodermal development.