DEVELOPMENTAL GENETICS OF NEURAL TUBE FORMATION

本研究将探讨基因相互作用在小鼠神经管中的作用。 发展。神经管的形成是最早的、最多的 哺乳动物胚胎发育中的关键事件和过程中的缺陷 (包括遗传缺陷)是人类最常见的先天缺陷之一。 这项研究将利用三种新诱导的小鼠突变， 根据它们与已知的影响基因的相互作用而分离出来的 神经管发育。这些新的突变体将被描述为 在遗传和发育方面，确定它们在 胚胎及其对其他神经管突变的修饰 已经描述过了。研究将包括连锁和作图、组织学 胚胎分析、双突变体构建及基因检测 致命的阶段。新的突变体被分离出来，因为它们与 导致神经管闭合失败的Splotch轨迹 纯合子状态，以及融合，产生神经的复制 在纯合子中的管子。对新的相互作用基因座的研究将有助于确定 正常神经管需要协调作用的一组基因 队形。 因为许多指导神经管发育的基因很可能 调节细胞相互作用，至关重要的是要确定一个突变体 缺陷是神经板细胞固有的，或者它是否导致 来自外在来源的异常细胞相互作用。为了解决这个问题 这个问题，我们将通过聚合突变和 野生型胚胎。这些细胞的基因类型将用一种新的 细菌β-半乳糖苷酶基因融合的分子标记 真核启动子的控制，它将被引入到 正常小鼠品系的胚系。因此，将有可能得分 突变细胞与野生型细胞的分布 切开的胚胎。以这种方式，可以进行关于哪一个 细胞必须携带一种特定的突变才能产生突变 表型，定义给定突变的细胞作用部位。这 技术将被用来绘制各种遗传和组织贡献的图谱 神经管发育，以及追踪神经管细胞谱系 神经管。 从长远来看，这类研究将确定所需的一组基因 为神经管的形成，并为分子研究奠定基础 这一过程。

This study will probe the role of gene interactions in mouse neural tube development. Formation of the neural tube is one of the first, most critical events in mammalian embryogenesis, and defects in the process (including genetic ones) are among the most common human birth defects. The study will make use of three newly induced mutations in the mouse, isolated on the basis of their interactions with loci known to affect neural tube development. These new mutants will be characterized genetically and developmentally, determining their morphological effects in embryos and the modifications they impose on other neural tube mutations already described. Studies will include linkage and mapping, histological analysis of embryos, construction of double mutants and determination of lethal phases. The new mutants were isolated for their interactions with the Splotch locus, which causes failure of neural tube closure in homozygous condition, and Fused, which produces duplications of the neural tube in homozygotes. The study of new interacting loci will help define the set of genes whose coordinate action is required for normal neural tube formation. Since many of the genes that direct neural tube development are likely to mediate cell interactions, it will be essential to establish if a mutant defect is intrinsic to cells of the neural plate, or whether it results from an abnormal cell interaction of extrinsic origin. In order to address this question, we will construct genetic mosaics by aggregating mutant and wild-type embryos. The cells' genotypes will be scored with a new molecular marker, a gene fusion placing bacterial Beta-galactosidase under the control of a eukaryotic promoter, which will be introduced into the germ line of a normal mouse strain. Thus, it will be possible to score the distribution of mutant vs. wild-type cells, using antibody staining of sectioned embryos. In this manner, a correlation can be made as to which cells must carry a particular mutation in order to produce the mutant phenotype, defining the cellular site of action of a given mutation. This technique will be used to map the various genetic and tissue contributions to neural tube development, as well as to trace the cell lineage of the neural tube. In the long run, studies of this sort will define the set of genes required for neural tube formation and lay the foundations for molecular studies of this process.