FUNCTIONAL ANALYSIS OF VERTEBRATE CAUDAL DEVELOPMENT

描述（根据申请人的描述改编）： 这个项目是为了了解形成的caudalmost部分的 脊椎动物胚胎这一区域产生了树干， 相关的内部器官和外部附属物。分泌分子 (e.g.维甲酸[RA]和成纤维细胞生长因子[Fgf]）是必需的 尾发育的调节因子，因为它们的失活会导致 尾部结构，但仍有很多需要了解这些因素如何 功能特别是，有一个确定的基因调控的缺乏， RA和Fgf的空间控制和体内Fgf和RA活性差 明白PI和他的同事已经分离出两个含锌指的 基因（DPZ和LMO 4）在斑马鱼胚胎中尾部表达， 解决这些问题。首先，dpz和lmo 4将有助于研究两个 关于FGF和RA活性的空间调节的问题。1)dpz和 Imo 4表达覆盖胚胎中的RA和FGF依赖性结构域。通过 分析这些基因的调控，PI将了解RA和Fgf如何在体内表达。 信号在体内被空间积分。2)有人认为，FGF 直接影响中胚层，但通过次级信号间接影响外胚层。 由于dpz和可能的lmo 4在外胚层和中胚层中表达， PI将讨论FGF在这些胚层中的作用是否不同。第二、 这些基因是新的，因为它们与大多数RA和Fgf调节的基因相反， 基因的特点，日期，不编码经典的DNA结合转录 因素因此，它们可能在不同水平的RA和Fgf发挥作用。 与已知的RA和Fgf调节基因相比，两个不同 将采取方法来确定DPZ和LMO 4如何在尾侧中起作用。 发展1)将斑马鱼突变株系用于瞬时表达 显性阴性构建体的体内表达，以确定RA/FGF 信号通路DPZ和LMO 4起作用。2）。dpz和lmo 4的作用将 通过进行救援实验来定义。为此，dpz和lmo 4将 在缺乏RA或FGF信号的斑马鱼胚胎中表达。通过确定 尾部发育的哪些方面可以被任何一个基因拯救，这将是 可以推断其正常功能。 这项工作将在几个方面对人类健康产生影响： 由遗传缺陷或暴露于环境引起的尾部发育 药物导致出生缺陷，如脊柱裂。这项工作将定义 尾部发育的步骤可能受到这种外部侮辱的影响， 提出了可以逆转的方法。此外，lmo 4与多种癌症有关。 (e.g.乳腺癌），其致癌潜力可能与其 在控制分化等基本过程中的正常作用。因此，在本发明中， 研究正常的lmo 4功能将有助于我们了解 肿瘤发生

DESCRIPTION (Adapted from applicant's description): The long-term goal of this project is to understand the formation of the caudalmost part of the vertebrate embryo. This region gives rise to the trunk as well as to associated internal organs and external appendages. Secreted molecules (e.g. Retinoic acid [RA] and Fibroblast growth factor [Fgf]) are essential regulators of caudal development, as their inactivation leads to loss of caudal structures, but much remains to be learned about how these factors function. In particular, there is a paucity of identified genes regulated by RA and Fgf and the spatial control of Fgf and RA activity in vivo is poorly understood. The PI and his colleagues have isolated two Zn finger-containing genes (dpz and lmo4) expressed caudally in the zebrafish embryo which will address these issues. First, dpz and lmo4 will help in the study of two questions concerning the spatial regulation of Fgf and RA activity. 1) dpz and lmo4 expression covers both RA and Fgf dependent domains in the embryo. By analyzing the regulation of these genes the PI will learn how RA and Fgf signals are integrated spatially in vivo. 2) It has been suggested that Fgf affects mesoderm directly, but ectoderm indirectly via a secondary signal. Since dpz, and possibly lmo4, is expressed in both ectoderm and mesoderm the PI will address whether Fgf acts differently in these germ layers. Second, these genes are novel in that they, in contrast to most RA and Fgf regulated genes characterized to date, do not encode classical DNA-binding transcription factors. They may therefore function at different levels of the RA and Fgf signaling pathways than known RA and Fgf regulated genes. Two different approaches will be taken to determine how dpz and lmo4 act in caudal development. 1) Zebrafish mutant lines will be used and transient expression of dominant negative constructs in vivo to define where in the RA/Fgf signaling pathways dpz and lmo4 function. 2). The roles of dpz and lmo4 will be defined by performing rescue experiments. To this end dpz and lmo4 will be expressed in zebrafish embryos that lack RA or Fgf signaling. By determining which aspects of caudal development can be rescued by either gene, it will be possible to infer their normal function. This work will have implications for human health in several ways: Defective caudal development caused by genetic defects or exposure to environmental agents results in birth defects such as spina bifida. This work will define steps in caudal development that may be affected by such external insults and suggest ways they can be reversed. Also, lmo4 is implicated in various cancers (e.g. breast cancer) and its oncogenic potential is likely related to its normal role in controlling basic processes such as differentiation. Thus, studying normal lmo4 function will help us understand aspects of tumorigenesis.