人衰老相关DNA片段的筛选及特征分析

Screening and characteristic analysis of human senescence-associated DNA fragment

目的 :探索衰老相关新基因。方法 :采用RAPD法筛选衰老相关的DNA片段 ,采用Southernblot分析基因状态 ,Northernblot分析mRNA水平。结果 :筛选出衰老特异的DNA片段 ,长 894bp ,命名为sad。将sad片段克隆、测序 ,查询GenBank ,确认为一种新的衰老相关序列 ,基因登录号为AQ32 410 4。Southernblot分析表明 ,sad基因可能是一种单拷贝基因 ;sad在衰老 2BS细胞中的Southernblot图谱不同于年轻细胞 ,而与人胃癌细胞系BGC 82 3类似。Northernblot分析显示 ,sad基因具有表达活性 ,其RNA长约 0 .5kb ,相对水平在各代龄的细胞间差异无显著性。结论 :sad是一种新的与衰老相关的DNA片段 ,sad基因可能为单拷贝基因 ,具有表达活性。

Objective: To search for new senescence associated gene. Methods: RAPD was used to screen the new senescence associated DNA fragment. Southern blot was used to study gene station and Northern blot was applied to analyze the mRNA level. Results: The 894bp DNA fragment, which was visible only in senescent 2BS cells, was found and named senescence associated DNA (sad). No sad homologous sequences were found in updated GenBank. GenBank accession number of sad was AQ324104. Southern blot showed that sad gene might be a one copied gene. Southern patterns of sad gene in senescent 2BS cells were different from that in young cells, but similar to patterns in BGC 823 cells. Northern blot showed sad was expressive in 2BS cells. The size of sad RNA was 0.5kb. The content of sad RNA in young 2BS cells was not different from that of the population doubling 25 to 56. Conclusion: sad was a new molecular marker linked to senescence associated gene. The sad gene may be a one copied gene, which expressed in 2BS cells.