| The development of body should pass the stages of fertilized egg, totipotent cells, multipotent cells, lineage progenitors, lineage committed cells, progenitor cells and differentiate into cells of special tissues in the end. Embryonic stem ( ES) cells are the cells which can be self - renewing and form all kinds of specialized cells in body. Researches on the development and differentiation of neural cells became easy by the use of ES cells. With the model in vitro, we can not only control the factors modulate development and differentiation, but also do the experiments on drug and toxicology. For a long time, neural system injury and neural degradation disease are problems unresolved on clinic. Stem cells will become the best source of cell replacement therapy and organ transplantation if moderately induced. Stem cells not only provide a useful model for the researches of embryo development and differentiation, but also are essential to cell replacement therapy and transplantation in clinic.ES cells are the cells derived from the inner cells mass (ICM). They are capable of differentiating in vitro into multiple cells types under the stimulation of right signals. Retinoic acid ( RA) , as a non - specific inducer, has been implied into the research on induction of ES cells.Unfolded protein response (UPR) , as a signal pathway from endoplasmic reticulum (ER) to nuclei, was first identified in yeast. Perturbations that disrupt the folding of proteins lead to the accumulation of unfolded proteins and protein aggregates in ERs. As a sequence, the cell evolved an adaptively coordinated response to limit further accumulation of unfolded proteins by expressing large amount of chaperons. In this pathway, Irel, an ER transmembrane protein kinase/endoribonuclease, is essential for viability during ER stress. In contrast to yeast, the mammalian genome contains two homologues of IRE1, IRElctandIRE1B, to sense the unfolded protein level. Deletion of Irelain mouse genome led to lethality at embryonic day 10. 5. By contrast, no developmental defect was detected on deletion of Ire1B. Whereas S. cerevisiae uses Irel/Hacl to repress differentiation, the Ire1/Xbp pathway promotes differentiation in mammalian tissues. Presently, it has been found that UPR signaling might promote differentiation of plasma cell in higher eukaryotic cells. However, the function of UPR in neuron development has not been reported yet.Embryonic development including human being is a series of interaction of cell - cell and cell - plasma. In the process of cell differentiation, part of the genes are activated selectively or expressed differently, which lead to the production and arrangement of special proteins. Neural genesis and neural differentiation, happen entangling, are the two basic facts in neural development.A variety of inducers were used in the research of ES cells induction. Recent studies have shown that a superphysiological dose of RA can produce a good proportion of neural cells, it has two apparent problems. First, it is difficult to analyze and control each regulatory step of differentiation in this method because embryonic bodies (EBs) , forming in the process of induction, contain many different kinds of cells. Second, RA, a strong teratogen, is supposed to perturb neural patterning and neuronal identities in EBs as it does in vivo . It is essential to get monotype differentiated cells by committedly induced ES cells. Present research proved that it is reasonable to explore ES cell committed induction pathway by transfecting special transcript factor, maker gene or relative cell differentiation factors combined with reporter gene and selecting method with inducer. Presently, the genes used in transfection are those already known playing role in neural development.The ibeE gene of . coli Kl is the pathogenesis gene that helps E. coli Kl to invade brain micro - vascular endothelial cells and cross blood - brain barrier. The open reading frame of the ibeE gene is 1383bp encoding a 50KD hypothetical protein. In E. coli...
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