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目的个体的端粒长度受到遗传和环境因素的共同调控,遗传度为35%～80%。人类端粒酶逆转录酶(human telomerase reverse transcriptase,hTERT)是端粒酶活性的限速成分,hTERT基因的序列变异与人类衰老相关的疾病风险密切相关,本研究拟探讨hTERT基因启动子区遗传变异对转录活性影响的功能研究。方法根据生物信息学预测和文献分析,本研究选择hTERT基因启动子区的两个单核苷酸多态性位点rs2735940(-1327T/C)和rs2853669(-190T/C),构建含有4种单体型的荧光素酶报告载体,包括野生型T-T,突变型T-C,C-T,C-C。由于rs2853669位于转录因子Ets2和c-Myc的结合位点,与c-Myc、Ets2真核表达载体共转染Hela细胞,检测荧光素酶活性变化,比较不同单体型对hTERT基因启动子转录活性的影响。结果研究结果表明,hTERT启动子区rs2853669携带C等位基因的单体型荧光素酶活性较低。与野生型T-T比较,单体型T-C的荧光素酶活性降低31%,单体型C-C的荧光素酶活性降低43%(P<0.001)。转录因子Ets2和c-Myc协同作用,显著增强hTERT基因启动子的活性(P<0.001)。结论 hTERT基因启动子区单体型遗传变异C-C(rs2735940-rs2853669)通过影响与转录因子Ets2和c-Myc的结合效率,降低该基因的转录活性和表达。
The telomere length of the target individuals is controlled by both genetic and environmental factors, and the heritability is 35% -80%. Human telomerase reverse transcriptase (hTERT) is a rate-limiting component of telomerase activity. The sequence variation of hTERT gene is closely related to the risk of human aging-related diseases. This study was to explore the genetic basis of hTERT gene promoter Function of Mutation on Transcriptional Activity. Methods According to the prediction of bioinformatics and literature analysis, we selected two SNPs rs2735940 (-1327T / C) and rs2853669 (-190T / C) in promoter region of hTERT gene, Monomeric luciferase reporter vectors, including wild-type TT, mutant TC, CT, CC. Since rs2853669 was located at the binding site of transcription factor Ets2 and c-Myc, the co-transfection of HeLa cells with c-Myc and Ets2 eukaryotic expression vectors was used to detect the changes of luciferase activity. The transcriptional activity of hTERT gene promoters was compared between different haplotypes Impact. Results The results showed that the haplotype luciferase activity of rs2853669 carrying the hTERT promoter region was lower than that of the c allele. Compared with wild-type T-T, the luciferase activity of haplotype T-C was reduced by 31% and the haplotype C-C luciferase activity by 43% (P <0.001). The transcription factor Ets2 and c-Myc synergistically enhanced the hTERT gene promoter activity (P <0.001). Conclusion The haplotype variation C-C (rs2735940-rs2853669) in promoter region of hTERT gene can reduce the transcriptional activity and expression of Ets2 and c-Myc by affecting the binding efficiency with Ets2 and c-Myc.