Telomerase Reverse Transcriptase Has an Extratelomeric Function in Somatic Cell Reprogramming
Telomerase Reverse Transcriptase Has an Extratelomeric Function in Somatic Cell Reprogramming
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DOI：
10.1074/jbc.m113.536037
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发表时间：
2014-05-30
影响因子：
4.8
通讯作者：
Suda, Toshio
中科院分区：
文献类型：
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作者：
Kinoshita, Taisuke;Nagamatsu, Go;Suda, Toshio
内源性端粒酶逆转录酶（TERT）催化亚基的再活化和端粒延长发生在体细胞重编程为诱导多能干细胞（iPS）期间。然而，TERT在重编程过程中的作用尚不清楚。为了阐明其功能，在TERT-KO体细胞中检查了重编程过程。为了排除端粒延长的影响，使用来自第一代TERT-KO小鼠的尾尖成纤维细胞（TTF）。虽然从TERT-KO TTF成功地产生了iPS细胞，但重编程这些细胞的效率明显低于WT TTF。由TERT-KO TTF诱导的iPS细胞的基因表达谱与WT iPS细胞和ES细胞的基因表达谱相似，并且TERT-KO iPS细胞形成分化为所有三个胚层的畸胎瘤。这些数据表明，端粒酶逆转录酶在重编程过程中发挥了端粒外的作用，但其功能是有限的。然而，TERT-KO iPS细胞在连续生长期间显示出短暂的生长缺陷和畸胎瘤形成。此外，TERT-KO iPS细胞产生染色体融合，其随着传代次数的增加而积累，这与TERT对于维持iPS细胞中的基因组结构和稳定性至关重要的事实一致。在拯救实验中，TERT的酶失活突变体（D 702 A）对TERT-KO TTF的体细胞重编程具有积极影响，这证实了TERT在该过程中的端粒外作用。
Reactivation of the endogenous telomerase reverse transcriptase (TERT) catalytic subunit and telomere elongation occur during the reprogramming of somatic cells to induced pluripotent stem (iPS) cells. However, the role of TERT in the reprogramming process is unclear. To clarify its function, the reprogramming process was examined in TERT-KO somatic cells. To exclude the effect of telomere elongation, tail-tip fibroblasts (TTFs) from first generation TERT-KO mice were used. Although iPS cells were successfully generated from TERT-KO TTFs, the efficiency of reprogramming these cells was markedly lower than that of WT TTFs. The gene expression profiles of iPS cells induced from TERT-KO TTFs were similar to those of WT iPS cells and ES cells, and TERT-KO iPS cells formed teratomas that differentiated into all three germ layers. These data indicate that TERT plays an extratelomeric role in the reprogramming process, but its function is dispensable. However, TERT-KO iPS cells showed transient defects in growth and teratoma formation during continuous growth. In addition, TERT-KO iPS cells developed chromosome fusions that accumulated with increasing passage numbers, consistent with the fact that TERT is essential for the maintenance of genome structure and stability in iPS cells. In a rescue experiment, an enzymatically inactive mutant of TERT (D702A) had a positive effect on somatic cell reprogramming of TERT-KO TTFs, which confirmed the extratelomeric role of TERT in this process.