The protein regulation to stem cell division

Stem cells themseves have many regulatory factors that may react to signals from outside world so as to adjust their proliferation and differentiation, including regulation of proteins with cell asymmetric division and control of gene expression of nuclear factor. In addition, the number of stem cell division before terminal differentiation of stem cells is also constrainted by intracellular regulatory factors. This is called endogenous regulation.

1. Intracellular protein regulation of stem cell division:

The differentiation of Stem cells can produce new stem cells or differentiated functional cells. This differentiation asymmetry is due to the unequal distribution of the cell's own components and other surroundings. Structural proteins of cells, in particular cytoskeletal component, is very important for the cell development. As in Drosophila ovary, the regulation of asymmetric stem cell division is a organelle called shrink body containing many regulatory proteins such as membrane contractile protein and cyclin A. The combination of the shrink body and spindle body determines the part of cell differentiation, thereby making the essential ingredients that maintain the stem cell traits remain in the progeny of stem cells.

2. The regulation of transcription factor:

In vertebrates, the regulation of transcription factors to stem cell differentiation is very important. For example, in the occurrence of embryonic stem cells, the transcription factor Oct4 is required. Oct4 is a transcription factor of mammalian early embryonic cell expression, and it induces the expression of the target gene product FGF-4 and other growth factors. It can regulate the further differentiation of stem cells and the surrounding trophoblast through making use of paracrine function of growth factor. If Oct4 deleted, mutant embryos only can develop to the blastocyst stage, while the internal cells can't develop into the inner cell mass. Besides, leukemia inhibitory factor (LIF) can promote cultured mouse ES cell self-renewal, but it has no effect on human adult stem cells, indicating that transcriptional regulation between different species is not entirely consistent. Another example is that the Tcf / Lef family of transcription factors is very important for the differentiation of epithelial stem cells. Tcf / Lef is intermediate medium of the Wnt signaling pathway. When formating transcriptional complex with the β-Catenin, Tcf / Lef can promote skin cells to turn into a pluripotent state and to differentiate into hair follicles. In the industry of biology, recombinant human protein technology is developing prosperously due to the findings above.