Transdifferentiation of stem cells: from the cell to the body

The phases of embryo development, starting with the formation of gametes and germlines, are considered. This study described the differences in the selection of germ and somatic cells. The formation of true germ cells is associated with the induction of bone morphogenetic protein. The zinc-finger transcription factor is the marker of the formation of true germ cells in primates. True germ cells have two types: germ cells that form endoderm and those that form an epiblast. Their differentiation is provided by the growth factor of fibroblasts due to the signaling protein FGF4, which interacts with the FGFR2 receptor in the primary endoderm. The migration of germ cells is controlled by the factors of stromal cells. The implantation of a fertilized egg is associated with the peculiarities of the differentiation of the trophectoderm and the influence of transcription factors. Since stem cell lines are isolated from non-brain tissues, their origin and development remain not fully established. In mice, the chorion is formed from a small area of trophectoderm covered with an out-of-the-mouth mesoderm on the proximal end of the egg lumen. In humans, the chorion, together with its basis—“non-embryonic mesoderm”—is the earliest appearance of tissue emanating from the primary endoderm. Modern research has confirmed the possibility of obtaining clones from the nuclei of early blastomere embryos. However, the use of cell nuclei at later stages yielded unsatisfactory results. The use of embryonic stem nuclei has produced much better results than the use of cells in the later stages of development. Therefore, whatever the source of the cores, they should be in the G0 or G1 phase, but not in G2.