GENETIC ANALYSIS OF MESODERM INDUCTION IN MICE

描述(改编自调查人员摘要)：这是一个修订后的 应用于研究MSD基因座在小鼠发育中的作用。 MSD突变表型包括不能形成中胚层和 基因座是由白化病患者体内一系列重叠的缺失定义的 很复杂。拟议研究的总体目标是了解 中胚层分化的遗传调控。《公约》的具体目标 建议是：1)确定MSD突变是否扰乱生长因子 发信号。2)评估MSD在开发过程中是否还有其他角色 除了参与中胚层的形成外，还有3)克隆MSD基因。 为达到特定目的1，标记的野生型ES细胞将被注射到MSD中 突变胚泡以确定MSD内胚层是否能够产生 中胚层诱导信号(S)。此外，Nodal的表达模式， BMP-4和Bmpr将在突变的MSD胚胎中进行检测，以确定MSD 阻断已知中胚层诱导的产生或接收的功能 信号。在相关的一系列实验中，调控的异位表达 中胚层信号通路的已知下游成分，如MAD1， 将检查T和MAPK绕过中胚层的能力 阻挡MSD突变体。在第2节中对MSD的其他描述 表型将包括处理细胞周期长度的实验 早期原肠发育，原位杂交研究以确定早期 MSD突变体表达前后轴形成的标志 胚胎，生产含有突变的MSD细胞的嵌合胚胎 野生型背景和新ENU诱导的MSD突变的分离 吉恩。在赠款的第三部分，克隆MSD区域的方法 都被描述了。它们包括分离跨越MSD的重叠群 利用cDNA法确定重叠群内转录单位的区域及鉴定 选择。MSD基因或多个基因将通过对突变株的拯救来鉴定 单个c DNA或c DNA转染人胚胎干细胞的实验研究 多个cDNA克隆。

DESCRIPTION (adapted from investigator's abstract): This is a revised application to study the function of the msd locus in mouse development. The msd mutant phenotype consists of a failure to form mesoderm and the locus is defined by a series of overlapping deletions within the albino complex. The broad goal of the proposed research is to understand the genetic regulation of mesoderm differentiation. The specific aims of the proposal are to 1) determine if the msd mutation disrupts growth factor signaling. 2) To assess whether msd has other roles during development besides its involvement in mesoderm formation, and 3) to clone the msd gene. For specific aim 1, marked wild type ES cells will be injected into msd mutant blastocysts to determine whether msd endoderm is able to produce a mesoderm inducing signal(s). In addition, the expression patterns of Nodal, BMP-4 and Bmpr will be examined in mutant msd embryos to determine if msd functions by blocking production or reception of known mesoderm inducing signals. In a related series of experiments, regulated ectopic expression of known downstream components of mesoderm signaling pathways such as Mad1 , T and Map kinase will be examined for their ability to bypass the mesoderm block in msd mutants. In section 2 additional characterization of the msd phenotype will include experiments to address the cell-cycle length during early gastrulation, in situ hybridization studies to determine if early markers of anteroposterior axis formation are expressed in msd mutant embryos, production of chimeric embryos containing mutant msd cells in a wildtype background, and isolation of new ENU induced mutations in the msd gene. In the third section of the grant, approaches to clone the msd region are described. They include the isolation of a contig spanning the msd region and identification of transcription units within the contig by cDNA selection. The msd gene or genes will be identified by rescue of mutant embryonic stem cells after transfection with either individual cDNA or multiple cDNA clones.