端粒及端粒酶的研究进展

Advances of Telomere and Telomerase

端粒是真核细胞染色体末端的特有结构,是由端粒结合蛋白和一段重复序列的端粒DNA组成的一个高度精密的复合体,在维持染色体末端稳定性,避免染色体被核酸酶降解等方面起着重要的作用。端粒的长度、结构及组织形式受多种端粒结合因子的调控。由于端粒的重要性,在哺乳动物细胞里,端粒的长度或端粒结构变化与癌症发生及细胞衰老有密切的关系。由于末端复制问题的存在,随着细胞分裂次数的增加,端粒不断缩短,细胞不可避免的走向衰老或凋亡。由于在细胞分裂过程中端粒长度的不断缩短与细胞分裂代数增加具有相关性,即端粒长度反应了细胞的分裂次数,因此有人将端粒形象的比喻为生物时钟。在90%的癌细胞中,端粒酶被重新激活,以此来维持端粒的长度,使细胞走向永生化。简要综述了端粒、端粒酶及端粒酶结合蛋白的最新研究进展。

Telomeres are specialized nucleoprotein complexes at the ends of linear chromosomes, consisting of multi-kilo- base long arrays of double-stranded TFAGGG repeats, a single-stranded overhang of the 3′G-strand, and associated proteins. It protects the ends of linear chromosomes. Telomere length, construction and organization are regulated by lots of telomere binding proteins. Because of the significance of telomeres, the changes of telomeres′ length or constructure can cause cells to enter senescence or apoptosis. Telomerase is important for maintaining telomeres, and most of cancer cells have telomerase activity, so, it can be a target for cure cancer. The latest development of the telomere, telomerase and its binding proteins function were discussed.