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目的 探讨造血干 祖细胞端粒酶相关蛋白基因hTERT和TEP1在造血过程中对端粒酶活性的调节作用。方法 用RT PCR和TRAP法分别测定脐血干 祖细胞中hTERT、TEP1mRNA及端粒酶的活性。结果 在新分离的脐血单个核细胞 (MNC)和CD3 4 - 细胞中检测不到端粒酶的活性 ,hTERTmRNA表达阴性 ;CD3 4+细胞中端粒酶活性低 ,hTERTmRNA阳性 ;而TEP1mRNA在MNC、CD3 4- 细胞和CD3 4+细胞中均为阳性 ,表达水平差异无显著性。在不同细胞因子组合条件下 ,CD3 4+细胞体外培养 7d ,细胞端粒酶活性和hTERTmRNA表达增高 ,之后随着细胞的分化成熟 ,二者表达降低 ,在整个培养过程中 ,TEP1mRNA表达无明显变化。结论 在脐血造血干 祖细胞中 ,hTERT基因表达水平与端粒酶活性一致 ,hTERT基因表达水平对端粒酶的活性起关键作用 ,TEP1基因作用较弱
Objective To investigate the regulation of telomerase activity in hematopoietic stem / progenitor cells by hTERT and TEP1 genes. Methods RT-PCR and TRAP were used to detect hTERT, TEP1 mRNA and telomerase activity in cord blood stem / progenitor cells respectively. Results Telomerase activity was undetectable in newly isolated cord blood mononuclear cells (MNC) and CD3 4 - cells, but hTERT mRNA expression was negative; telomerase activity was low and hTERT mRNA was positive in CD3 4+ cells; while TEP1 mRNA was not detected in MNC , CD3 4-cells and CD3 4+ cells were positive, the expression level was no significant difference. Under different combinations of cytokines, CD3 4+ cells cultured in vitro for 7 days showed an increase in telomerase activity and hTERT mRNA expression, and then decreased as the cells matured. TEP1 mRNA expression did not change significantly during the whole culture . Conclusion The expression of hTERT gene in umbilical cord blood hematopoietic stem / progenitor cells is consistent with telomerase activity. The expression of hTERT gene plays a key role in the activity of telomerase, while the effect of TEP1 gene is weak