Analysis on the gene expression and the function of FGFs and FGF receptors during induction of differentiation of embryonal carcinoma cells.

本研究观察了维甲酸诱导小鼠胚胎癌P19细胞（EC P19）向神经元分化过程中成纤维细胞生长因子（FGF）及其受体（FGFRs）基因表达的变化。EC P19细胞是多能性的，并且可以通过将细胞聚集体暴露于10 μ M至10 μ M浓度的视黄酸（RA）来诱导其分化为神经元和神经胶质细胞<-7><-6>。这些神经元在形态上类似于中枢神经系统中的神经元，并且许多神经元特异性基因显示在这些细胞中表达。因此，上述系统是一个很好的模型，在体外研究什么事件发生在神经元分化的关键阶段。在诱导P19细胞的神经元分化时，包括FGF 2、FGF 6和FGF 9的三种FGF的基因表达增加。在FGFR中，FGFR 2的基因表达显著增加，而FGFR 1的基因表达保持不变。没有RA处理的细胞聚集体的形成是没有的。 关于我们 不足以诱导神经元分化;大多数细胞保持未分化，但一小部分细胞成为心肌细胞。在这些条件下，这些FGF未被诱导。相反，FGF 5和FGF 8的表达大大增加。因此，FGF 2、FGF 6和FGF 9可能在神经元发育中发挥重要作用，例如刺激生长、存活和细胞-细胞粘附。其中，RA诱导细胞表达的小鼠FGF 9 cDNA序列是首次报道。小鼠与人FGF 9 cDNA的同源性为92.4%，与大鼠的同源性为98.2%。该小鼠FGF 9 cDNA编码由208个氨基酸组成的多肽，其氨基酸序列与大鼠相同。与人类同源物相比，仅一个氨基酸被替换。FGF 9的高度保守序列同源性提示了其功能的重要性，并通过抗FGF 9抗体染色检测了P19细胞神经元分化过程中FGF 9蛋白的表达。神经元被抗体强烈染色，神经胶质细胞也被染色。本研究表明，FGF 9在神经元发育中起重要作用，例如，刺激神经元和胶质细胞的生长和功能的维持。少

The changes in the gene expression of fibroblast growth factors (FGFs) and the receptors for FGFs (FGFRs) during retinoic acid-induced neuronal differentiation of mouse embryonal carcinoma -derived P19 cells (EC P19) were examined in this study. EC P19 cells are pluripotent and can be induced to differentiate into neurons and glia cells by exposing cell aggregates to retinoic acid (RA) at 10^<-7> M to 10^<-6>M concentraitons. These neurons resemble morphologically those in the central nervous system, and many neuron-specific genes were shown to be expressed in those cells. Thus, the above system is a good model for studying in vitro what events occur during the critical phase of neuronal differentiation. Gene expression of three FGFs, including FGF2, FGF6, and FGF9 was increased on induction of neuronal differentiation of P19 cells. Among FGFRs, the gene expression of FGFR2 was greatly increased, while that of FGFR1 was constant. Formation of cell aggregates without RA treatment was no … More t enough to induce neuronal differentiation ; most of the cells remained undifferentiated, but a small portion of the cells became heart muscle cells. Under these conditions these FGFs were not induced. In contrast, FGF5 and FGF8 were greatly increased in their expression. Thus, FGF2, FGF6, and FGF9 may play important roles in neuronal development, for example, stimulating growth, survival, and cell-cell adhesion. Among these FGFs, the sequence of mouse FGF9 cDNA expressed in the cells induced by RA was first reported. The murine cDNA showed 92.4% nucleotide sequence homology to the human FGF9 cDNA and 98.2% homology to that of rats. This mouse FGF9 cDNA encoded a polypeptide consisting of 208 amino acids with amino acid sequence identical to that of rats. Only one amino acid was replaced compared to the human homolog. The highly conserved sequence homology of FGF9 suggests its functional importance.The protein expression of FGF9 during the neuronal differentiation of P19 cells was also examined by staining the cells with anti-FGF9 antibody. Neurons were strongly stained with the antibody, and glial cells were also stained. This study suggests that FGF9 plays important roles in neuronal development, for example, stimulating growth and maintenance of the function of neurons and glial cells. Less