hTERT增加TRF2以诱导端粒紧缩并延长细胞复制寿命
Nancy Adam1, Yang Yang1, Mahbod Djamshidi1
1Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Departments of Biochemistry & Molecular Biology and/or Oncology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Aging cell
|May 15, 2025
概括
表达突变hTERT的人类细胞通过压缩端粒来避免衰老,而不是通过延长它们. 这种端粒紧缩,独立于长度,阻止DNA损伤信号和复制停止,提供了对癌细胞行为的见解.
科学领域:
- 细胞衰老 细胞衰老
- 端粒生物学 端粒生物学
- 对DNA损伤的反应反应
背景情况:
- 复制性衰老是一种限制细胞增殖的过程,由短端粒和DNA损伤信号通过ATM和TP53.3触发.
- 人类端粒酶逆转录酶 (hTERT) 已知可以延长端粒,可能防止衰老.
研究的目的:
- 研究hTERT突变体在端粒维护和衰老中的作用.
- 阐明hTERT变种影响DNA损伤信号传递和细胞复制的机制.
主要方法:
- 利用了表达各种hTERT突变的正常双胞胎纤维细胞.
- 评估端粒长度,DNA损伤信号 (ATM,TP53) 和细胞复制.
- 测量了E3无素连接酶 (Siah1,CDC20,FBXO5) 和shelterin复合体组件 (TRF1,TRF2) 的水平.
- 使用超高分辨率显微镜分析端粒构造.
主要成果:
- hTERT突变,即使是那些没有保持端粒长度的突变,也阻止了DNA损伤信号和衰老.
- 突变hTERT表达改变了E3酶水平,稳定了TRF2并恢复了TRF2:TRF1比率.
- 端粒采用了更紧,更密集的形状,独立于长度,这与减少的DNA损伤信号相关.
- 这种由TRF2调解的端粒紧缩被确定为阻断衰老的关键因素.
结论:
- hTERT变体可以通过端粒紧缩来抑制衰老,这是与端粒延长不同的一种机制.
- 由shelterin复合体和E3结合酶调节的端粒紧缩,在防止复制性衰老方面发挥着主导作用.
- 癌细胞中的短端粒可能会由于稳定的shelterin成分和增加的端粒密度而避免衰老,而不仅仅是由于缺乏hTERT活动.
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