Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands.
Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, Netherlands.
Life Sci Alliance. 2022 Jan 11;5(4). doi: 10.26508/lsa.202101153. Print 2022 Apr.
Eukaryotic cells have evolved a replication stress response that helps to overcome stalled/collapsed replication forks and ensure proper DNA replication. The replication checkpoint protein Mrc1 plays important roles in these processes, although its functional interactions are not fully understood. Here, we show that negatively interacts with , which encodes the helicase protein Chl1, suggesting distinct roles for these factors during the replication stress response. Indeed, whereas Mrc1 is known to facilitate the restart of stalled replication forks, we uncovered that Chl1 controls replication fork rate under replication stress conditions. Chl1 loss leads to increased gene expression and dNTP levels at the onset of S phase likely without activating the DNA damage response. This in turn impairs the formation of RPA-coated ssDNA and subsequent checkpoint activation. Thus, the Chl1 helicase affects RPA-dependent checkpoint activation in response to replication fork arrest by ensuring proper intracellular dNTP levels, thereby controlling replication fork progression under replication stress conditions.
真核细胞已经进化出一种复制应激反应，有助于克服停滞/崩溃的复制叉，并确保正确的 DNA 复制。复制检查点蛋白 Mrc1 在这些过程中发挥着重要作用，尽管其功能相互作用尚不完全清楚。在这里，我们表明 与 相互作用， 编码解旋酶蛋白 Chl1，表明这些因子在复制应激反应中有不同的作用。事实上，虽然已知 Mrc1 有助于停滞复制叉的重新启动，但我们发现 Chl1 在复制应激条件下控制复制叉的速度。Chl1 的缺失导致在 S 期开始时增加了 基因的表达和 dNTP 水平，而没有激活 DNA 损伤反应。这反过来又损害了 RPA 包被的 ssDNA 的形成以及随后的检查点激活。因此，Chl1 解旋酶通过确保适当的细胞内 dNTP 水平来影响复制叉停滞时对 RPA 依赖性检查点激活，从而控制复制应激条件下的复制叉进展。
