人类Cdc25A的快速破坏是对DNA损伤的反应
1Institute of Cancer Biology, Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen, Denmark.
Science (New York, N.Y.)
|May 29, 2000
概括
人类细胞在DNA损伤时降解Cdc25A酸酶,以停止细胞周期的进展并允许修复. 这种机制涉及Chk1激酶,防止复制并促进生存,Cdc25A过度表达可能导致癌症.
科学领域:
- 分子生物学分子生物学
- 细胞循环规则 细胞循环规则
- 对DNA损伤的反应反应
背景情况:
- 细胞具有在基因毒性压力下保护基因组完整性的机制.
- 细胞循环停止是一个至关重要的生存策略,允许DNA修复时间.
- 蛋白酸酶Cdc25A对于细胞周期从G1到S阶段的进展至关重要.
研究的目的:
- 研究Cdc25A降解在细胞对基因毒性压力的反应中的作用.
- 阐明涉及DNA损伤引起的Cdc25A.失活的分子途径.
- 探索Cdc25A失调对人类癌症发展的影响.
主要方法:
- 暴露人类细胞的基因毒剂 (紫外线,电离辐射).
- 对蛋白质降解途径的分析,重点关注依赖于无素和蛋白酶体的机制.
- 对细胞循环调节蛋白的研究,包括Cdc25A,Chk1,p53和Cdk2.2.
- 功能性研究涉及Cdc25A过度表达,以评估其对DNA损伤和生存的影响.
主要成果:
- 基因毒性压力迅速诱导了人类细胞中Cdc25A的乌比奎和蛋白酶体依赖的降解.
- 这种降解是由激活的Chk1蛋白激酶介导的,独立于p53通路.
- 持续的Cdk2抑制酸化阻止了进入S相和DNA复制.
- 过度表达Cdc25A导致DNA损伤增加和细胞存活率降低,绕过检查点.
结论:
- 特定降解Cdc25A是DNA损伤检查点机制的一个组成部分.
- 这一途径通过防止受损DNA的复制来确保基因组完整性.
- 人类癌症中Cdc25A过度表达可能通过破坏DNA修复和促进基因组不稳定性,导致瘤发生.
相关概念视频
02:25Overview 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...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:36DNA 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...
02:25Overview 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...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:36DNA 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...