Department of Genetic Resources Technology, Faculty of Agriculture, Kyushu University, Fukuoka, 812-8581, Japan.
Cytotechnology. 2010 Aug;62(4):333-9. doi: 10.1007/s10616-010-9276-y. Epub 2010 May 8.
Telomerase-a complex ribonucleoprotein enzyme-synthesizes telomeric repeats to avoid telomere loss that accompanies cell division and chromosomal replication. Expression of telomerase is detectable in embryonic cells and cancer cells, but not in normal human cells. On the other hand, in mice, substantial expression of telomerase is detected in normal cells and tissues as well as in immortalized cells. These results suggest that the regulatory mechanisms of telomerase activity in humans and mice differ. Considering these results along with the fact that the expression of the telomerase reverse transcriptase (TERT) gene is a rate-limiting step for telomerase activity, we compared transcriptional regulatory mechanisms of both the species. A series of luciferase assays and RT-PCR analyses demonstrated that c-Myc, a dominant transactivator for human TERT (hTERT), is not involved in the regulation of mouse TERT (mTERT). These results suggest that distinct molecules and pathways are involved in the process of immortalization and tumorigenesis in human and mouse cells.
端粒酶是一种复杂的核蛋白酶，可合成端粒重复序列，以避免伴随细胞分裂和染色体复制的端粒丢失。端粒酶在胚胎细胞和癌细胞中可检测到表达，但在正常人体细胞中则不能。另一方面，在小鼠中，端粒酶在正常细胞和组织以及永生化细胞中都有大量表达。这些结果表明，人类和小鼠中端粒酶活性的调控机制不同。考虑到这些结果以及端粒酶逆转录酶（TERT）基因的表达是端粒酶活性的限速步骤，我们比较了两种物种的转录调控机制。一系列荧光素酶检测和 RT-PCR 分析表明，人端粒酶（hTERT）的主要转录激活因子 c-Myc 不参与小鼠端粒酶（mTERT）的调节。这些结果表明，在人类和小鼠细胞的永生化和肿瘤发生过程中涉及不同的分子和途径。
