RETROVIRUSES AS PROBES FOR DEVELOPMENT

早期的发展将通过建立在小鼠身上进行研究 原肠胚前期的细胞谱系，并由 影响发育的插入突变的产生 转基因小鼠。 在这项工作中，小鼠胚胎将在 不同的发展阶段。结果是，单个细胞 胚胎将被贴上基因标签，因此嵌合体 将在早期用于跟踪细胞谱系 发展。为了便于追踪受感染的细胞和 他们的后代，逆转录病毒载体被引入小鼠胚胎 将编码一种容易识别和无害的基因产物，如 细菌的β-半乳糖苷酶基因。逆转录病毒将是 被引入植入前阶段的胚胎，以及在卵子中 圆柱体阶段的胚胎，以建立一张命运图 原肠胚在原肠形成之前或在原肠形成时的小鼠胚胎尤其是， 将对该胚系的起源进行调查。 马赛克动物将与野生型动物繁殖产生 胚中含有单一前病毒基因组的转基因菌株 排队。这些菌株将被分析，以调查 父母对转基因表达的印记，并推导出 新的逆转录病毒诱导的突变。普罗鲁斯将用作 标签用于克隆侧翼基因组序列并鉴定 突变的基因。这种方法应该有助于更好地 了解在早期发育过程中活跃的基因。

Early development will be studied in the mouse by the establishment of cell lineages in the pre-gastrulation embryo, and by the generation of insertional mutations affecting development in transgenic mice. In this work, mouse embryos will be infected with retroviruses at different stages of development. As a result, individual cells of the embryo will be labelled genetically, and the mosaicism thus generated will be used to follow cell lineages during early development. To facilitate tracking of the infected cells and their progeny, retroviral vectors introduced into mouse embryos will encode an easily identifiable and innocuous gene product, such as the bacterial beta galactosidase gene. Retroviruses will be introduced into preimplantation stage embryos, as well as in egg cylinder stage embryos, in order to establish a fate map of the mouse embryo prior to or at gastrulation. In particular, the origin of the germ line will be investigated. Mosaic animals will be bred with wild-type animals to generate transgenic strains containing a single proviral genome in the germ line. These strains will be analyzed to investigate the effect of parental imprinting on expression of the transgene, and to derive new retroviral-induced mutations. The proviruses will be used as tags to clone flanking genomic sequences and to identify the mutated genes. This approach should contribute to a better understanding of genes active during early development.