Objective To investigate the effects of location of stop codon and attenuation of nonsense-mediated mRNA decay on reading through levels of atalruen, an anti-premature termination agent. Methods The premature nonsense mutants of dual chromatic expression vector pDsRed-EGFPmtag-Y596X and pDsRed-EGFPmtag-Y653X were constructed by rapid site-directed mutagenesis PCR, and were used to transfect mammalian cell line COS7. The transfected COS7 cells were examined for expression and read-through level of DsRed and EGFP in the non-sense mutations by using qRT-PCR in the presence or absence of atalruen, siRNA-upf1 and CHX. Results Quantitative PCR analysis showed that pDsRed-EGFPmtag-Y653X in the COS7 cells was more sensitive than pDsRed-EGFPmtag-Y596X to the effect of atalruen in promoting the read-through level. The read-through levels were not affected by the attenuation of nonsense-mediated mRNA decay by siRNA-upf1 and CHX. Conclusion Efficiency of suppression de-pends in part on the identity of the +4 nucleotide immediately downstream from the stop codon (C>A). Different with aminoglycoside antibiotics, the read-through level may not be promoted by synergistic effect of atalruen and NMD at-tenuation.%目的：探讨终止密码子上下文结构和无义突变介导的mRNA降解途径（NMD）抑制对抗早发性无义突变（PTC）药物atalruen通读效率的影响。方法利用聚合酶链反应（PCR）定点突变的方法构建双荧光哺乳动物表达载体的早发性无义突变体pDsRed-EGFPmtag-Y596X和pDsRed-EGFPmtag-Y653X，转染哺乳动物细胞COS7，抗早发性无义突变药物atalruen，结合siRNA-upf1、放线菌酮（CHX）共同作用转染细胞，采用实时荧光定量PCR反应检测突变体上红色荧光蛋白（DsRed）和绿色荧光蛋白（EGFP）的表达，测定通读效率。结果PTC突变体pDsRed-EGFPmtag-Y653X对atalruen的促通读敏感性显著大于pDsRed-EGFPmtag-Y596X；siRNA-upf1和CHX抑制NMD对atalruen的促通读效率没有显著影响。结论 PTC位点的＋4位核苷酸对于atalruen的促通读效率十分关键，该位置是胞嘧啶（C）的突变体敏感性要显著大于腺嘌呤（A）；atalruen与常见促通读氨基糖苷类药物不同，不能协同NMD途径的抑制来促进早发性无义突变的通读。
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