title: [Expression of Notch1 gene in the differentiation of the human embryonic neural stem cells to neurons].
abstract: OBJECTIVE
  To explore the expression and role of Notch1 gene in the differentiation of the human embryonic neural stem cells to neurons induced by all-trans-retinoic-acid(ATRA).
  
  
  METHODS
  The human embryonic neural stem cells were induced with various concentrations of ATRA(0.5, 1, 5 and 10 mumol/L) in vitro. Immunofluorescence staining was performed after seven days, and neurons were quantified by counting NSE positive cells. Then human embryonic neural stem cells were induced to differentiate with 1 mumol/L ATRA. Total RNA was extracted from the cells before inducing, induced for 3 days, and for 7 days. The expression of Notch1 gene was tested by semi-quantitative RT-PCR.
  
  
  RESULTS
  The ratio of neural stem cells to differentiate to neurons was improved greatly by ATRA induction as compared with control group (P<0.01). 1 mumol/L ATRA was the optimal dose for induction of the human embryonic neural stem cell differentiation. The percentage of neurons induced by 1 micromol/L ATRA was (29.20+/-1.09)%. The expression of Notch1 gene decreased significantly after being treated with ATRA(P<0.001).
  
  
  CONCLUSIONS
  ATRA can greatly increase the percentage of neurons in the course of inducing the human embryonic neural stem cells to differentiate. Notch1 gene is down-regulated when human embryonic neural stem cells differentiate into neurons.
authors.affiliation: Department of Neurosurgery, Tongji Hospital of Tongji University, Shanghai 200065, China. wangf_sh@sina.com.cn
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.forename: Shi-ting
authors.initials: ST
authors.lastname: Li
authors.forename: Qiang
authors.initials: Q
authors.lastname: Huang
authors.forename: Qing
authors.initials: Q
authors.lastname: Lan
mesh_terms: D001921:Brain / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects*; D004622:Embryo, Mammalian; D015870:Gene Expression; D006801:Humans; D009474:Neurons / Q000166:cytology*; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D051881:Receptor, Notch1; D014212:Tretinoin