Showing papers by "Allan Bradley published in 1986"
TL;DR: The use of retroviral vectors to introduce exogenous DNA sequences into a stem- cell line is reported and it is shown that these modified cells contribute extensively to the somatic and germ-cell lineages in chimaeric mice.
Abstract: Embryonic stem cells isolated directly from mouse embryos1 can be cultured for long periods in vitro and subsequently repopulate the germ line in chimaeric mice2,3. During the culture period these embryonic cells are accessible for experimental genetic manipulation4–6. Here we report the use of retroviral vectors to introduce exogenous DNA sequences into a stem-cell line and show that these modified cells contribute extensively to the somatic and germ-cell lineages in chimaeric mice. Compared with current methods for manipulation of the mouse genome, this approach has the advantage that powerful somatic-cell genetic techniques can be used to modify and to select cells with germ-line potential, allowing the derivation of transgenic strains with pre-determined genetic changes. We have by this means inserted many proviral vector sequences that provide new chromosomal molecular markers for linkage studies in the mouse and that also may cause insertional mutations.
812 citations
TL;DR: The applications that are considered in the chapter focus on the current direction of research—that is, the differentiation of recently isolated stem cells in an embryonic environment.
Abstract: Publisher Summary Fertilization or parthenogenetic activation of the mouse egg initiates a series of cell divisions, which in the case of the fertilized egg ultimately results in the development of an adult individual. As the cell divisions proceed and cell numbers increase, differential gene expression is responsible for the phenotypic divergence of cells resulting in the formation of discrete cell types. This change is known as “differentiation.” As the expression of specific genes becomes fixed within certain cell types, it is accompanied by the commitment, to a greater or lesser degree, of the differentiated cell types to specific lineages within the developing organism. Although the use of embryonal carcinoma (EC) cells as a model of early mammalian development has been well justified, their use should not preclude an appreciation of two important limitations of the experimental material. First, although most EC cell lines are phenotypically very similar, they encompass a wide spectrum of differentiation potentials, often associated with a variety of karyotypic changes. Second, EC cells are derived from tumors and they should, therefore, be considered as neoplastic, or at any rate an abnormal, cell type. The recent development of techniques that have facilitated the direct isolation and culture of pluripotential stem cells from the mouse embryo has presented a number of novel approaches for the study of early mammalian development, using some aspects of the EC cell system. The applications that are considered in the chapter focus on the current direction of research—that is, the differentiation of these recently isolated stem cells in an embryonic environment.
63 citations