在破裂的DNA上,DNA损伤检查点激酶Mec1-Ddc2及其激活剂DPb11之间的分子相互作用
Emily C Beckwitt1, Gabriella N L Chua1,2, Shixin Liu3
1Laboratory of DNA Replication, The Rockefeller University, New York, NY, USA.
bioRxiv : the preprint server for biology
|December 8, 2025
概括
DNA损伤检查点蛋白Dpb11招募Mec1-Ddc2到受损的DNA部位. Dpb11稳定了DNA结构,促进了Mec1的激活,以维护基因组.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 遗传学 遗传学 是一个
背景情况:
- 在真核生物中,DNA损伤检查点对于基因组稳定至关重要.
- Mec1 (ATR) 和 Ddc2 (ATRIP) 是检测DNA损伤的关键组成部分.
- Mec1的激活需要与特定的激活蛋白相互作用.
研究的目的:
- 阐明Mec1在受损DNA上遇到其激活剂的机制.
- 研究DPb11 (TopBP1) 在招募Mec1-Ddc2到DNA损伤中的作用.
- 了解DPb11如何与DNA结构相互作用并影响Mec1定位.
主要方法:
- 检查点蛋白在缺口DNA上的实时单分子成像.
- 单分子力谱法用于分析蛋白质-DNA相互作用.
- 使用芽酵母作为一个模型系统.
主要成果:
- Dpb11与单链DNA和RPA涂层DNA结合,在独立于9-1-1的ss-dsDNA连接处定位.
- 直接可视化证实DPb11将Mec1-Ddc2复合体招募到ss-dsDNA连接处.
- Dpb11形成了DNA桥梁,稳定了ssDNA循环,并减少了DNA间隙的距离.
结论:
- Dpb11直接将Mec1-Ddc2招募到DNA受损部位.
- Dpb11通过改变DNA拓来间接促进Mec1的激活.
- 这些发现揭示了检查点蛋白的同位化和激活的新机制.
相关概念视频
02:36DNA Damage can Stall the Cell Cycle
9.9K
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...
9.9K
02:36DNA Damage Can Stall the Cell Cycle
3.0K
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...
3.0K
02:37Restarting Stalled Replication Forks
6.2K
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart,...
6.2K
01:02Long-patch Base Excision Repair
7.8K
Since the discovery of the two BER pathways, there has been a debate about how a cell chooses one pathway over the other and the factors determining this selection. Numerous in vitro experiments have pointed out multiple determinants for the sub-pathway selection. These are:
7.8K
02:04Fixing Double-strand Breaks
14.2K
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...
14.2K
02:31Homologous Recombination
62.4K
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
62.4K