Lomonosov Moscow State University, Chemistry Department.
Acta Naturae. 2012 Apr;4(2):44-61.
Telomerase is an enzyme that maintains the length of the telomere. The telomere length specifies the number of divisions a cell can undergo before it finally dies (i.e. the proliferative potential of cells). For example, telomerase is activated in embryonic cell lines and the telomere length is maintained at a constant level; therefore, these cells have an unlimited fission potential. Stem cells are characterized by a lower telomerase activity, which enables only partial compensation for the shortening of telomeres. Somatic cells are usually characterized by the absence of telomerase activity. Telomere shortening leads to the attainment of the Hayflick limit, the transition of cells to a state of senescence. The cells subsequently enter a state of crisis, accompanied by massive cell death. The surviving cells become cancer cells, which are capable both of dividing indefinitely and maintaining telomere length (usually with the aid of telomerase). Telomerase is a reverse transcriptase. It consists of two major components: telomerase RNA (TER) and reverse transcriptase (TERT). TER is a non-coding RNA, and it contains the region which serves as a template for telomere synthesis. An increasing number of articles focussing on the alternative functions of telomerase components have recently started appearing. The present review summarizes data on the structure, biogenesis, and functions of telomerase.
端粒酶是一种维持端粒长度的酶。端粒的长度决定了细胞在最终死亡之前可以进行多少次分裂(即细胞的增殖潜能)。例如,端粒酶在胚胎细胞系中被激活,端粒长度保持在恒定水平;因此,这些细胞具有无限的分裂潜能。干细胞的特征是端粒酶活性较低,只能部分补偿端粒缩短。体细胞通常特征是缺乏端粒酶活性。端粒缩短导致达到海弗利克极限,即细胞向衰老状态的转变。随后,细胞进入危机状态,伴随着大量细胞死亡。存活的细胞变成癌细胞,这些细胞能够无限分裂并维持端粒长度(通常借助端粒酶)。端粒酶是一种逆转录酶。它由两个主要成分组成:端粒酶 RNA(TER)和逆转录酶(TERT)。TER 是一种非编码 RNA,它包含作为端粒合成模板的区域。最近开始出现越来越多聚焦于端粒酶成分的替代功能的文章。本综述总结了关于端粒酶的结构、生物发生和功能的数据。