HERITABILITY OF EMBRYONIC RADIOSENSITIVE TARGETS

嵌合体试验是检测体内暴露的一种敏感试验 哺乳动物的生殖细胞受到电离辐射。这种暴露会导致 在培养的小鼠身上表现出的细胞增殖缺陷 植入前胚胎。在检测中，来自未暴露的4-细胞胚胎 父母与来自暴露的雄性或雌性的4-细胞胚胎配对 双亲形成聚合嵌合体。化验的终点是 “增殖率”，这是由 实验配对胚胎除以细胞总数 包括2-3轮细胞分裂后的嵌合体。比率 明显小于0.5表示比实验配对胚胎 在嵌合体中表现出细胞增殖的劣势。子代细胞 目前区分这两个配对胚胎的方法是将 嵌合体前用胞质染料FITC作对照的配对胚胎 建筑。然而，来自连续细胞分裂的标记稀释 排除种植后分析和遗传力测试。 该项目的目标是开发一种增强的嵌合体检测方法，以 检查亲代生殖细胞暴露对男性的影响 坚持到植入和分娩之后。我们的第一个具体目标是 加入可遗传的非表达转基因细胞谱系标记以 在嵌合体分析中取代短期细胞谱系标记FITC。这个 第二个具体目标是使用我们的转基因细胞谱系标记来扩展 嵌合体分析在胚胎移植后分析中的应用 发展。第三个具体目标是将嵌合体分析应用于 转基因细胞系标记物用于亲代后遗传力检测 暴露在生殖毒物中。

The chimera assay is a sensitive test for detecting in vivo exposure of the mammalian germ cell to ionizing radiation. This exposure results in a cell proliferation disadvantage that is expressed in cultured mouse preimplantation embryos. In the assay, 4-cell embryos from non-exposed parents are paired with 4-cell embryos from either exposed male or female parents to form aggregation chimeras. The assay's endpoint is a "proliferation ratio", which is the number of cells contributed by the experimental partner embryo divided by the total number of cells comprising a chimera after 2-3 rounds of cell division. Ratios significantly less than 0.5 indicate than an experimental partner embryo expressed a cell proliferation disadvantage in the chimera. Progeny cells from the two partner embryos are currently distinguished by labelling the control partner embryo with the cytoplasmic dye FITC prior to chimera construction. However, label dilution from successive cell divisions precludes postimplantation analyses and heritability tests. This project's objective is to develop an 'enhanced' chimera assay to examine the effects of parental germ cell exposure in the male that persist beyond implantation and birth. Our First Specific Aim is to incorporate a heritable non-expressing transgenic cell lineage marker to replace the short-term cell lineage marker FITC in the chimera assay. The Second Specific Aim is to use our transgenic cell lineage marker to extend the chimera assay into postimplantation analyses of fetal and postnatal development. The Third Specific Aim is to apply the chimera assay with the transgenic cell lineage marker for heritability testing after parental exposure to reproductive toxicants.