Dorsal-Ventral Pattern Formation in the Zebrafish Embryo

描述（由申请人提供）：沿背-腹侧（DV）胚胎轴的模式形成是脊椎动物胚胎中多种细胞类型建立的基础。骨形态发生蛋白（BMP）信号通路是这一模式形成过程的关键。bmp被假定作为形态形成因子，沿着DV轴建立不同的细胞命运。然而，由于难以解决有关BMP梯度作用的关键问题，目前的背腹模式和BMP信号梯度模型在本质上仍然是相当基础的。一些新的分子遗传工具，结合斑马鱼独特的细胞方法，将在本提案中被利用，以显着扩展脊椎动物DV模式的当前模型。两个问题的中心模型的DV模式和BMP信号将被调查。首先，BMP梯度在DV模式中的时间作用将使用可诱导的转基因进行测试。将确定梯度是否在原肠胚形成期间协调作用以指定所有腹侧细胞命运，或者它是否在多个时间点起作用。其次，将研究BMP信号梯度的空间方面。在正常的生理条件下，一个有效的原肠BMP信号梯度范围将被定义，它在体内给定的时间内主动指定不同的细胞类型，形成因子的关键特性。将对梯度的空间范围进行功能检查。最后，为了通过功能丧失研究最大限度地了解DV模式和BMP梯度的产生、调节和作用，确定该途径中的所有遗传参与者至关重要。为此，将分析一个未被表征的背化突变基因，该基因可能是该途径的新组成部分。这些研究与人类疾病的研究直接相关，因为这一途径中的一些基因已被证明或与多种人类疾病状态和人类遗传性疾病的病因有关。

DESCRIPTION (provided by applicant): Pattern formation along the dorsal-ventral (DV) embryonic axis is fundamental in the establishment of the diverse cell types found in vertebrate embryos. A Bone Morphogenetic Protein (BMP) signaling pathway is key in this pattern formation process. BMPs are postulated to act as morphogens to establish distinct cell fates along the DV axis. Current models for dorsal-ventral patterning and the BMP signaling gradient are still rather basic in nature, however, due to difficulties in addressing key questions regarding BMP gradient action. A number of new molecular genetic tools, combined with unique cellular methods in the zebrafish, will be exploited in this proposal to significantly extend upon the current models of vertebrate DV patterning. Two issues central to models of DV patterning and BMP signaling will be investigated. First the temporal action of the BMP gradient in DV patterning will be tested using inducible transgenes. It will be determined if the gradient acts coordinately during gastrulation to specify all ventrolateral cell fates or if it acts at multiple time points. Secondly, spatial aspects of the BMP signaling gradient will be examined. An effective gastrula BMP signaling gradient range will be defined under normal physiological conditions, which actively specifies distinct cell types during a given time period in vivo, key properties of morphogens. The spatial extent of the gradient will be examined functionally. Lastly, to maximize understanding of DV patterning and BMP gradient generation, regulation, and action through loss-of-function studies, it is critical to identify all the genetic players in the pathway. To this end, an uncharacterized dorsalized mutant gene will be analyzed, which may be a novel component of this pathway. These studies are directly relevant to the study of human disease, since some of the genes in this pathway have been shown or are implicated in the cause of multiple human disease states and human inherited disorders.