Stem cells: an origin and marks

The basic physiological functions of stem cells are given: the ability to reproduce and generate offspring, which are manifested at the level of the population, and not of a single cell. The manifestation of these functions depends on the quantitative and qualitative composition of the microenvironment. Stem cells consist of two fundamentally different types: pluripotent, which exist only in vitro (in vitro) and tissue, existing in the postpartum body (in vivo). Stem cells can be replaced without limitation in vitro and lead to the appearance of a wide range of cell types. Tissue stem cells under normal conditions do not generate cells characteristic of other types of tissue. Stem cells include cells capable of expressing the gene products characteristic of them. However, there is no universal marker to differentiate stem cells from non-stem cells. A key marker of pluripotency is the transcription factor - a pituitary-specific transcription factor is positive. A component that can be found in almost all types of stem cells is the telomerase complex. Another stem cell marker is called CD34 glycoprotein. The functional activity of stem cells is associated with a molecular marker referred to as leucine-rich repeat containing G-protein bound to receptor 5. However, other types of cells do not express this marker. The physiological capabilities of stem cells depend both on the cells themselves and on their environment. The most reliable way to identify stem cells is to determine their phenotype in vivo. This suggests that stem cells do not carry a universal molecular marker. Most likely, they have significant differences from transplanted cells, and these differences cannot always be detected in individual cells, but only at the population level.