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目的探讨人类神经前体细胞中内源性人端粒酶反转录酶(hTERT)基因的转录活性及增殖与分化相关调控机制。方法采用系列hTERT基因启动子的荧光素酶报告载体和β-半乳苷酶表达载体,瞬时共转染HeLa细胞和hNPCs-G3细胞,检测不同长度启动子的活性。分析碱性成纤维细胞生长因子(bFGF)促进增殖过程中hTERT基因启动子活性,分析cAMP诱导分化过程中hTERT基因启动子活性。结果 hNPCs-G3神经前体细胞内源性hTERT基因的转录活性较低,主要依赖近端启动子区。bFGF上调hNPCs-G3神经前体细胞内源性hTERT基因的表达,其调控主要作用在-2 098～-1 099bp区域和-3 216bp～-2 098bp区域内;cAMP抑制hNPCs-G3神经前体细胞hTERT基因的转录,其调控主要作用在近端启动子区。结论神经前体细胞内源性hTERT基因的转录活性较低,bFGF可上调神经前体细胞内源性hTERT基因的表达,cAMP则可抑制hTERT基因的转录。
Objective To investigate the transcriptional regulation of endogenous human telomerase reverse transcriptase (hTERT) gene in human neural progenitor cells and its regulatory mechanisms of proliferation and differentiation. Methods A series of hTERT gene promoter luciferase reporter vector and β-galactosidase expression vector were transiently co-transfected into HeLa cells and hNPCs-G3 cells to detect the activity of different length promoters. The promoter activity of hTERT gene during the proliferation was analyzed by bFGF, and the promoter activity of hTERT gene during cAMP induced differentiation was analyzed. Results The hTERT gene of hNPCs-G3 neural progenitor cells had low transcriptional activity and mainly depended on the proximal promoter region. bFGF upregulates the expression of hTERT gene in hNPCs-G3 neural progenitor cells. The main role of bFGF is in the region of -2 098 ~ -1 099 bp and the region of -3 216 bp ~ -2 098 bp; cAMP inhibits the expression of hNPCs-G3 neural progenitor cells hTERT gene transcription, the regulation of the main role in the proximal promoter region. Conclusions The endogenous hTERT gene of neural progenitor cells has low transcriptional activity. BFGF can upregulate the expression of endogenous hTERT gene in neural progenitor cells while cAMP can inhibit the transcription of hTERT gene.