在衰老过程中,DNA修复对血造干细胞具有限制性
Anastasia Nijnik1, Lisa Woodbine, Caterina Marchetti
1Henry Wellcome Building for Molecular Physiology, Oxford University, Oxford OX3 9DU, UK.
Nature
|June 8, 2007
概括
修复DNA损伤对于干细胞衰老至关重要. 在小鼠中,一种特定的DNA结合酶IV突变显示,受损的DNA双链断裂修复加速了干细胞的枯竭和衰老.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 老年学是一门学科.
背景情况:
- 积累的DNA损伤与衰老和干细胞枯竭有关.
- 基因酶IV (Lig4) 在通过非同源端结合 (NHEJ) 在DNA双链断裂修复中发挥关键作用.
研究的目的:
- 研究DNA结合酶IV在衰老和干细胞功能中的作用.
- 用于研究LIG4综合征和衰老,对一种具有低形态Lig4突变 (Lig4(Y288C)) 的新型小鼠模型进行表征.
主要方法:
- 使用一种突变发生查程序来识别Lig4(Y288C) 鼠标菌株.
- 在Lig4(Y288C) 小鼠中评估了DNA双链断裂修复效率.
- 评估了血液形成干细胞 (HSC) 功能,骨髓细胞性和干细胞在衰老过程中的体外和体外行为.
主要成果:
- 在Lig4(Y288C) 鼠标模型中,表现出免疫缺陷和生长迟缓,模仿人类LIG4综合征.
- 在Lig4(Y288C) 小鼠中,DNA双链断裂修复的减少导致随着年龄的增长,HSCs和骨髓细胞性逐渐丧失.
- 损坏的NHEJ在组织培养和移植环境中显著损害HSC功能.
结论:
- 缺少DNA双链断裂修复,特别是通过NHEJ,是血液造血干细胞衰老和耗尽的关键因素.
- Lig4 ((Y288C) 鼠标是了解DNA修复缺陷对干细胞维护和与衰老相关疾病的影响的一个有价值的模型.
相关概念视频
Nucleotide Excision Repair
Overview
Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
Nucleotide Excision Repair
Overview
DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
Nucleotide Excision Repair
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...


