英国弗朗西斯·克里克研究所Hasan Yardimci等研究人员合作揭示DNA复制终止过程中姐妹染色单体凝聚的建立。相关论文于2024年3月14日在线发表于国际学术期刊《科学》。

通过观察单个复制叉与预先装载的黏连蛋白复合物碰撞的情况，研究人员发现复制体反而会将黏连蛋白推向遇到会聚复制体的地方。在DNA复制终止时，会聚的复制体会被移除，而黏连蛋白则留在新生DNA上，提供凝聚。此外，研究人员还发现，在复制终止过程中，CMG的分解对于芽殖酵母的正常凝聚至关重要。

总之，这些研究结果支持一种新的模式，即在DNA复制终止过程中建立姐妹染色单体的凝聚。

据悉，新复制的姐妹染色单体通过黏连蛋白复合物拴在一起，但姐妹染色单体的凝聚如何与DNA复制相协调却鲜为人知。流行的模型认为，复制前与DNA结合的黏连蛋白复合物会留在前进的复制叉后面，使姐妹染色单体保持在一起。

附：英文原文

Title: Sister chromatid cohesion establishment during DNA replication termination

Author: George Cameron, Dominika T. Gruszka, Rhian Gruar, Sherry Xie, ala Kaya, Kim A. Nasmyth, Jonathan Baxter, Madhusudhan Srinivasan, Hasan Yardimci

Issue&Volume: 2024-03-14

Abstract: Newly copied sister chromatids are tethered together by the cohesin complex, but how sister chromatid cohesion is coordinated with DNA replication is poorly understood. Prevailing models suggest cohesin complexes, bound to DNA before replication, remain behind the advancing replication fork to keep sister chromatids together. By visualizing single replication forks colliding with pre-loaded cohesin complexes, we find that the replisome instead pushes cohesin to where a converging replisome is met. While the converging replisomes are removed during DNA replication termination, cohesin remains on nascent DNA and provides cohesion. Additionally, we show that CMG disassembly during replication termination is vital for proper cohesion in budding yeast. Together, our results support a new model where sister chromatid cohesion is established during DNA replication termination.

DOI: adf0224

Source: https://www.science.org/doi/10.1126/science.adf0224