Development · 1972 · 229 citations · 21 references
Life SciencesBiologyDevelopmental BiologyCell DifferentiationEmbryogenesisEmbryologyBlastocyst DevelopmentEarly Embryonic DevelopmentEmbryo DevelopmentEmbryonic DevelopmentMammalian DevelopmentPreimplantation Embryo DevelopmentBlastocyst FormationBlastocyst MorphologyCell Lineage AllocationEmbryo MorphogenesisEmbryology Of The Reproductive SystemInner Cell Mass DifferentiationMouse Embryogenesis ModelsTissue Organization In Development
The study examined how the spatial position of blastomeres influences cell fate in mouse embryos. Researchers combined embryos and embryo fragments during early preimplantation development and tracked differentiation by prelabeling cells with tritiated thymidine or using cells with distinct electrophoretic variants of glucose phosphate isomerase. Each blastomere of a 4‑cell embryo can generate both trophoblast and inner cell mass, but when positioned on the outside of other embryos it preferentially forms the outer layer, trophoblast, and yolk sac and does not contribute to fetal coat color; surrounded 4‑ to 8‑cell embryos lose vesicle‑forming capacity, showing that at the 4‑ and 8‑cell stages cell position, not intrinsic factors, directs fate.
ABSTRACT The effect of cell position on cell determination was studied in mouse embryos. Embryos and parts of embryos were combined during early preimplantation development. The differentiation of cells in these composites was followed either by prelabelling some cells with tritiated thymidine or by combining cells which synthesized different electrophoretic variants of glucose phosphate isomerase. It was found that each blastomere of a 4-cell embryo could form both the trophoblast and the inner cell mass of the blastocyst. However, when blastomeres of a 4-cell embryo were placed on the outside of other 4-cell embryos then (a) they tended to form the outside layer of the blastocyst, (b) they tended to develop into the trophoblast and the yolk sac on the 10th day of pregnancy, (c) they tended not to form the coat colour of the foetus. Four-to eight-cell embryos which were completely surrounded by other blastomeres had lost the capacity to form vesicles at the blastocyst stage. We could find no evidence for the segregation of morphogenetic factors at the 4- and 8-cell stages of mouse development and concluded that at these stages cell position could determine the development of blastomeres.
21
Methods in developmental biology
Fred H. Wilt, Norman K. Wessells · Medical Entomology and Zoology · 1967 · 1.6K citations