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以酿酒酵母细胞为实验材料 ,在分子水平上研究铅 (Pb)和硒 (Se)对端粒长度、端粒酶及端粒结合蛋白的影响。结果发现 :与对照组相比 ,添加 1mg/LPb的培养基中培养 10 0代后的酿酒酵母细胞中端粒DNA的平均长度缩短 ,端粒结合蛋白Rap1p含量减少 ,而且Rap1p蛋白的二级结构受到扰动、端粒酶活性降低、43%的细胞死亡。加 1mg/LSe培养 10 0代后的酿酒酵母细胞与对照组相比 ,细胞中端粒平均长度增加 ,Rap1p蛋白浓度和二级结构保持稳定 ,端粒酶活性增加 ,细胞正常存活。以上结果表明 ,Pb对酿酒酵母细胞端粒有损伤 ,而且其损伤在子代细胞中有累积效应 ;而Se对Pb损伤具有一定程度的修复保护作用 ,适量给机体补Se对抑制细胞损伤和衰老有一定作用。由于端粒的特殊结构特征 ,推断Pb和Se是通过作用于端粒酶及端粒结合蛋白而间接影响端粒长度的
Using Saccharomyces cerevisiae cells as experimental material, the effects of Pb and Se on telomere length, telomerase and telomere binding protein were investigated at the molecular level. The results showed that compared with the control group, the average length of telomere DNA in S. cerevisiae cells cultured in the medium supplemented with 1mg / LPb for 10 years was shortened, the content of Rap1p in telomere protein was decreased, and the secondary structure of Rap1p protein Disturbed, telomerase activity decreased, 43% of the cells died. Compared with the control group, the average length of telomere increased, the Rap1p protein concentration and secondary structure remained stable, the telomerase activity increased and the cells survived normally. These results indicated that Pb could damage the telomere of Saccharomyces cerevisiae cells, and its damage had a cumulative effect in progeny cells. However, Se had a certain degree of repair and protection against Pb injury. Have a role. Due to the special structural features of telomeres, Pb and Se are inferred to indirectly affect telomere length by acting on telomerase and telomere binding proteins