Gene regulatory network evolution and the origin of biological novelties

描述(申请人提供)：细胞在发育期间通过组合基因活动的不同途径获得其独特的命运。控制内胚层细胞命运规范的基因调控网络(GRN)已经在包括海胆、脊椎动物和线虫在内的几个模型系统中构建。产生内胚层(肠衍生物)和中胚层(肌肉、血液、体腔、肾脏和骨骼元素)细胞类型的内胚层前体通过不同的基因表达而不同于外胚层前体(形成表皮和神经系统)。随后根据内胚层前体确定不同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，并重建不同动物物种之间的基因调控网络，可以为如何以及何时建立每个生物的分子和形态特征提供关键的见解。一个最好的例子是动物进化中中胚层的原始进化外观。海葵类(海葵、珊瑚和“水母”)是一类动物，其成虫只有两个胚层的衍生物，即外胚层和双功能(兼具吸收和收缩功能)的胃胚层(肠道)。刺尾目动物是其他具有全部三个胚层的两侧对称动物的近亲，分子、基因组、发育和进化方面的证据表明刺尾目动物的腹皮是所有其他三倍母细胞双侧动物中内胚层和中胚层的进化先驱。因此，解开这个犬科动物的“内胚层”基因调控网络，将提供必要的洞察，了解GRN亚回路是如何在各种后生动物中被采用、重新连接或增选的，以便产生新的、修饰的或专门化的内胚层特征。这笔赠款将在功能上重建海葵Nematostella vetensis(其基因组已由J.G.I(DEP.)测序)内胚层形成的基因调控网络。能源)，使用，定量聚合酶链式反应，全基因组微阵列，功能技术，如药物治疗，合成信使核糖核酸的错误表达，翻译和剪接阻断吗啡方法和顺式调控分析。此外，我们将把所有获得的数据输入到现有的基因表达数据库中，以便与科学界分享我们的发现。首次从一个具有系统发育关键作用的物种中产生高质量的分子数据，将有助于通过极化进化变化的方向来解释以前在双边模型系统中发现的基因及其调控相互作用的差异。 与公共卫生相关：项目叙述发育中的动物胚胎中的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。在一些模式物种中，我们已经了解到这些基因如何在复杂的基因调控网络(GRN)中相互调节功能。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)是如何从共同的内胚层前体产生的。这些新的数据将提供对不同系统中GRN差异的意义的洞察，并提示涉及内胚层发育异常的特定基因相互作用。

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.