TELOMERE SHORTENING IS ASSOCIATED WITH CELL-DIVISION IN-VITRO AND IN-VIVO
TELOMERE SHORTENING IS ASSOCIATED WITH CELL-DIVISION IN-VITRO AND IN-VIVO
复制标题
DOI：
10.1006/excr.1995.1306
复制
发表时间：
1995-09-01
影响因子：
3.7
通讯作者：
HARLEY, CB
中科院分区：
文献类型：
--
作者：
ALLSOPP, RC;CHANG, E;HARLEY, CB
在人类中，在体外和体内，在各种体细胞类型的老化过程中，末端（TTAGGG）（n）端粒DNA的量减少。虽然导致端粒缩短的因素尚未完全确定，但DNA复制机制无法完全复制染色体末端（“末端复制问题”）以及体细胞中缺乏端粒酶（从头合成端粒DNA的酶）是一种可能的机制。这一假说的一个预测是端粒缩短应该依赖于细胞分裂。因此，我们在体外和体内分析了活跃分裂和静止细胞中的端粒长度。在培养的人二倍体成纤维细胞（HDF）的环状增生中，外周细胞的平均末端限制性片段（TRF）长度（P = 0.011）和端粒信号强度（P = 0.024）显著低于中心细胞。此外，保持静止的HDF的端粒随时间缩短的速率在统计学上不显著（m =-12bp/天，P = 0.16），而连续传代的细胞的端粒随时间缩短的速率是显著的（m =-34bp/天，P = 0.017）。为了检查体内静止细胞的端粒缩短速率，我们测量了来自年龄范围从32-75岁的成年供体的脑组织中的平均TRF长度。与有丝分裂活性细胞体内老化过程中发生的端粒长度缩短（P = 0.0001）相比，未观察到随供体年龄的显著降低（P = 0.087）。这些观察结果表明，端粒缩短在很大程度上，如果不是完全依赖于细胞分裂，并支持末端复制问题作为这个过程的机制和使用端粒长度作为复制能力的生物标志物。(C)出版社：Academic Press
In humans, the amount of terminal (TTAGGG)(n), telomeric DNA decreases during aging of various somatic cell types in vitro and in vivo. While the factors accounting for telomere shortening have not been thoroughly established, the inability of the DNA replication machinery to completely copy chromosomal termini (the ''end replication problem'') and the absence in somatic cells of telomerase, the enzyme that synthesizes telomeric DNA de novo, is a likely mechanism. One prediction of this hypothesis is that telomere shortening should be dependent on cell division. Thus we analyzed telomere length in actively dividing and quiescent cells in vitro and in vivo. In circular outgrowths of cultured human diploid fibroblasts (HDF), cells at the outer periphery had a significantly lower mean terminal restriction fragment (TRF) length (P = 0.011) and telomeric signal intensity (P = 0.024) than cells at the center. Also, the rate of telomere shortening over time for HDFs held quiescent was not statistically significant (m = -12 bp/day, P = 0.16) while that for serially passaged cells was significant (m = -34 bp/day, P = 0.017). To examine the rate of telomere shortening for quiescent cells in vivo we measured mean TRF length in brain tissue from adult donors ranging in age from 32-75 years. No significant decrease was observed as a function of donor age (P = 0.087), in contrast to the shortening of telomere length that occurs during in vivo aging of mitotically active cells (P = 0.0001). These observations show that telomere shortening is largely, if not entirely, dependent on cell division and support the end replication problem as a mechanism for this process and the use of telomere length as a biomarker for replicative capacity. (C) 1995 Academic Press, Inc.