MOLECULAR ANALYSIS OF HINDBRAIN FORMATION

脊椎动物中枢神经系统(CNS)的形成 胚胎发育被认为是由两个过程启动的； 首先，背侧外胚层通过以下方式诱导形成吻部神经命运 来自中胚层的信号；第二，随后对 一些这种组织到更尾部的命运，也通过来自 中胚层。这两个过程共同创建了一个包含 特殊结构(前脑、中脑、后脑和脊髓) 沿着它的肩尾轴。随着胚胎发育的进行，其中的每一个 结构通过进一步的发展过程变得精致，直到它们 在成人身上执行不同的功能。分泌的可溶性分子 通过中胚层似乎既介导了神经化(例如，noggin和 Chordin)和尾化(例如成纤维细胞生长因子和维甲酸 酸)功能。我们认为，每一项技术的进一步发展 结构将由这些因子激活的基因介导， 因此启动了基于消减杂交的分子筛查 来分离这些基因。我们最初分离了激活的基因 可能是斑马鱼胚胎的后脑。五个基因(Meis1，niz， HoxA1、NH7、NH13)是本发明的主题 求婚。选择Meis1、NIZ、HoxA1、NH7和NH13进行分析 因为它们都是在外胚层中表达的 上升到后脑。NH7和Meis1似乎仅限于 在原肠形成过程中，后脑及其下面的中胚层，而 其他基因在更广泛的区域表达。Meis1、HoxA1和NIZ都是 似乎编码转录因子，而蛋白质的类型 由NH7和NH13编码的基因目前还不清楚。我们将分析 对胚胎中这些基因的调节以及解决它们的 在后脑发育中的作用。后者将同时实现两个目标 通过功能实验获得，在那里基因被表达 以确定它们的效果，并通过功能丧失 实验中，基因或其产物被灭活 遗传的或由显性干扰蛋白引起的。 这些实验将在两个方面对人类健康产生影响。 首先，Meis1和Hox两个基因的失调都有牵连。 小鼠和人髓系白血病及其正常情况的研究 因此，该功能将有助于阐明肿瘤的发生。第二，由于神经性 组织在发育早期仍在再生，这些基因调节 从长远来看，这一过程可能被用于修复神经组织 成人因创伤或退行性疾病而受损。

The formation of the vertebrate central nervous system (CNS) during embryonic development is thought to be initiated by two processes; first, the induction of dorsal ectoderm to a rostral neural fate by signals from mesoderm and second, the subsequent 're-programming' of some of this tissue to more caudal fates, also by signals from the mesoderm. Together these two processes create a CNS that contains specific structures (forebrain, midbrain, hindbrain and spinalcord) along its rostrocaudal axis. As embryogenesis proceeds, each of these structures becomes refined by further developmental processes until they carry out distinct functions in the adult. Soluble molecules secreted by the mesoderm appear to mediate both the neuralizing (e.g. noggin and chordin) and caudalizing (e.g. fibroblast growth factor, and retinoic acid) functions. We reasoned that the further development of each structure would be mediated by genes activated by these factors and therefore initiated a subtractive hybridization-based molecular screen to isolate such genes. We initially isolated genes activated in the presumptive hindbrain of the zebrafish embryo. Five genes (Meis1, niz, HoxA1, NH7, NH13) isolated in the screen are the subject of this proposal. Meis1, niz, HoxA1, NH7 and NH13 were selected for analysis because they are all expressed in the region of the ectoderm that give rise to the hindbrain. NH7 and Meis1 appear restricted to the hindbrain, and its underlying mesoderm, during gastrulation, while the other genes are expressed in broader domains. Meis1, HoxA1 and niz all appear to encode transcription factors, while the type of protein encoded by NH7 and NH13 is unclear at this point. We will analyze the regulation of these genes in the embryo as well as address their function in hindbrain development. The latter will be accomplished both by gain of function experiments, where the genes are expressed ectopically to determine their effect, and by loss of function experiments, where the genes, or there products, are inactivated genetically or by dominant interfering proteins. These experiments will have an impact on human health in two ways. First, the dysregulation of both Meis1 an Hox genes have been implicated in murine and human myeloid leukemias and understanding their normal function will therefore shed light on oncogenesis. Second, since neural tissue is still regenerating early in development, genes that regulate the process may, in the longer term, be used to repair neural tissue damaged by trauma or degenerative diseases in the adult.