端粒及端粒酶研究的最新进展

The last advances in study of telomere and telomerase

端粒是位于真核细胞染色体末端由重复ＤＮＡ序列和蛋白组成的复合物，它具有保护染色体、介导染色体复制、引导减数分裂时的同源染色体配对和调节细胞衰老等方面的作用。正常体细胞每分裂一代，端粒就会缩短一段，而端粒酶的作用是将一段端粒序列加到端粒末端，从而维持端粒长度。正常体细胞中是没有端粒酶活性的，而在大多数肿瘤细胞中都发现了端粒酶的表达，提示端粒和端粒酶在癌症发生和肿瘤细胞行为中具有重要作用。

Telomeres are repetitive DNA-protein complex at the end of eucaryotic chromosomes. It is thought that telomeres play a key role in protecting the Chromosomes, mediating the raplication of the chromosomes ,initiating the homolog alignment during meiosis and regulating the senescence of the cells. Telomeres in normal somatic cells shorten every division , telomerases can prevent the Shortening of the telomeres by adding repetitive sequences to the end of the telomeres. In most normal somatic cells, telomerases are repressed, while in most cancer cells , telomerases are activated. It implies the important role of the telomeres; in the tumorigenesis and the behaviour of the cancer cells.