Replication-Coupled PCNA Unloading by the Elg1 Complex Occurs Genome-wide and Requires Okazaki Fragment Ligation.
Replication-Coupled PCNA Unloading by the Elg1 Complex Occurs Genome-wide and Requires Okazaki Fragment Ligation.
复制标题
DOI：
10.1016/j.celrep.2015.06.066
复制
发表时间：
2015-08-04
期刊：
影响因子：
8.8
通讯作者：
Donaldson AD
中科院分区：
文献类型：
--
作者：
Kubota T;Katou Y;Nakato R;Shirahige K;Donaldson AD
滑动夹 PCNA 是 DNA 复制机制的重要组成部分。及时的 PCNA 加载和卸载对于基因组完整性至关重要，并且必须与复制过程中的其他 DNA 处理步骤严格协调。在这里，我们展示了酿酒酵母 Elg1 复制因子 C 样复合物 (Elg1-RLC) 在冈崎片段连接后在全基因组范围内卸载 PCNA。在缺乏 Elg1 的情况下，PCNA 在复制叉后保留在染色体上，而不是保留在特定位点。冈崎片段连接酶 Cdc9 的降解导致 PCNA 在染色质上积聚，类似于 Elg1 缺失引起的积聚。我们证明冈崎片段连接是 PCNA 卸载的关键先决条件，因为小球藻病毒 DNA 连接酶可以替代酵母中的 Cdc9，同时促进 PCNA 卸载。我们的结果表明，Elg1-RLC 充当通用 PCNA 卸载程序，并且依赖于染色体复制过程中的 DNA 连接。 PCNA 保留在所有缺乏 Elg1 的复制叉后面 Elg1-RLC 无法从未连接的滞后链 DNA 中卸载 PCNA 外源连接酶可以连接冈崎片段以促进 PCNA 卸载 Elg1-RLC 充当通用 PCNA 卸载程序，依赖于冈崎片段连接 滑夹 PCNA 对于 DNA 复制保真度至关重要，必须严格控制 PCNA 的加载和卸载。久保田等人。发现 Elg1 复合体在所有复制叉后面卸载 PCNA，并且依赖于滞后链上冈崎片段的成功 DNA 连接。
The sliding clamp PCNA is a crucial component of the DNA replication machinery. Timely PCNA loading and unloading are central for genome integrity and must be strictly coordinated with other DNA processing steps during replication. Here, we show that the S. cerevisiae Elg1 replication factor C-like complex (Elg1-RLC) unloads PCNA genome-wide following Okazaki fragment ligation. In the absence of Elg1, PCNA is retained on chromosomes in the wake of replication forks, rather than at specific sites. Degradation of the Okazaki fragment ligase Cdc9 leads to PCNA accumulation on chromatin, similar to the accumulation caused by lack of Elg1. We demonstrate that Okazaki fragment ligation is the critical prerequisite for PCNA unloading, since Chlorella virus DNA ligase can substitute for Cdc9 in yeast and simultaneously promotes PCNA unloading. Our results suggest that Elg1-RLC acts as a general PCNA unloader and is dependent upon DNA ligation during chromosome replication. PCNA is retained behind all replication forks that lack Elg1 Elg1-RLC cannot unload PCNA from unligated lagging-strand DNA An exogenous ligase can join Okazaki fragments to promote PCNA unloading Elg1-RLC acts as a general PCNA unloader, dependent upon Okazaki fragment ligation The sliding clamp PCNA is crucial to DNA replication fidelity, and loading and unloading of PCNA must be strictly regulated. Kubota et al. find that the Elg1 complex unloads PCNA behind all replication forks and is dependent upon successful DNA ligation of Okazaki fragments on the lagging strand.