特异性siRNA抑制hTERT基因表达的位置及时间效应

Positional and time effects of specific siRNA inhibit the expression of hTERT

为了探讨不同位点siRNA在不同时间点对人乳腺癌细胞系MCF-7细胞中hTERT mRNA表达的抑制作用,设计并化学合成4对针对人端粒酶逆转录酶(hTERT)基因的特异性siRNA。以脂质体法转染入MCF-7细胞,在转染后12h、24h、48h、72h和5d,用半定量逆转录聚合酶链反应(RT-PCR)检测细胞中hTERT mRNA的表达。与对照组相比,4段siRNA中有3段在转染后12h即对hTERT mRNA的表达产生抑制,48h抑制率最高,72h后下降,其中位于hTERT mRNA二级结构中的结构相对简单区域的siRNA抑制率最高,达到75%,说明特异性siRNA对hTERT基因有明显的抑制效果,且该抑制效应具有位置及时间依赖性。

To explore the inhibitory effect in diferent positions siRNA on hTERT mRNA expression in MCF-7 cells at the different time points, we Designed and chemically synthesized four pairs of siRNA which aimed at human telomerase reverse transcriptase （hTERT） gene specifically, which were transfected into the MCF-7 cells by liposome method, and then the expression of hTERTmRNA in MCF-7 cells was tested respectively by half-quantity RT-PCR at 12 h, 24 h, 48 h, 72 h, and 5 d after transfection. Compared with the control groups, there were three pieces of siRNA that inhibit the expression of hTERTmRNA at 12 h after transfection among the four pieces. The highest inhibition ratio occurred at 48 h after transfection, and after 72 h the ratio descended, when the siRNA sequence was located at the relative simple structure site in the secondary structure of hTERT mRNA had the highest inhibition ratio, which was 75%（P〈0.01）, which indicated that the specific siRNA had obvious inhibition effect on hTERT gene, and the effect was dependant positionally and timely dependence.