Enhanced H2AX phosphorylation, DNA replication fork arrest, and cell death in the absence of Chk1.
Enhanced H2AX phosphorylation, DNA replication fork arrest, and cell death in the absence of Chk1.
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DOI：
10.1091/mbc.e09-07-0618
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发表时间：
2010-03-01
影响因子：
3.3
通讯作者：
Meuth M
中科院分区：
文献类型：
--
作者：
Gagou ME;Zuazua-Villar P;Meuth M
丝氨酸139位的H2AX磷酸化（γH2AX）是DNA损伤和复制应激的敏感指标。在不存在Chk1的情况下，用复制抑制剂处理的细胞中γH2AX水平强烈增强。我们的数据表明，这种磷酸化在停滞或废弃的复制叉中持续存在，但不会使细胞死亡。丝氨酸139位的H2AX磷酸化（γH2AX）是DNA损伤和DNA复制应激的敏感指标。在这里，我们表明，γH2AX的形成大大提高了响应复制抑制剂，但不是电离辐射在HCT 116或SW480细胞耗尽Chk1。虽然H2AX磷酸化先于这些细胞中的凋亡诱导，但我们的结果表明，含有γH2AX的细胞不会死亡。这些细胞中的γH2AX灶主要与RPA灶共定位，它们的形成依赖于必需的复制解旋酶辅因子Cdc45，表明H2AX磷酸化发生在停滞叉的位点。然而，从复制抑制剂释放的Chk1耗尽的细胞保留γH2AX焦点，并且似乎不恢复复制性DNA合成。BrdU掺入仅发生在从胸苷阻滞释放后含有γH2AX灶的少数Chk 1耗尽细胞中，并且在掺入BrdU的细胞中，在γH2AX灶的位点不发生DNA合成。此外，激活的ATM和Chk2在这些细胞中持续存在。我们认为Chk1缺失细胞中的γH2AX灶可能代表了持续复制叉损伤或放弃的位点，这些位点无法恢复DNA合成，但在Chk1抑制的死亡途径中不起直接作用。
H2AX phosphorylation at serine 139 (γH2AX) is a sensitive indicator of DNA damage and replication stress. γH2AX levels are strongly enhanced in cells treated with replication inhibitors in the absence Chk1. Our data suggest that this phosphorylation persists at stalled or abandoned replication forks but does not commit cells to death. H2AX phosphorylation at serine 139 (γH2AX) is a sensitive indicator of both DNA damage and DNA replication stress. Here we show that γH2AX formation is greatly enhanced in response to replication inhibitors but not ionizing radiation in HCT116 or SW480 cells depleted of Chk1. Although H2AX phosphorylation precedes the induction of apoptosis in such cells, our results suggest that cells containing γH2AX are not committed to death. γH2AX foci in these cells largely colocalize with RPA foci and their formation is dependent upon the essential replication helicase cofactor Cdc45, suggesting that H2AX phosphorylation occurs at sites of stalled forks. However Chk1-depleted cells released from replication inhibitors retain γH2AX foci and do not appear to resume replicative DNA synthesis. BrdU incorporation only occurs in a minority of Chk1-depleted cells containing γH2AX foci after release from thymidine arrest and, in cells incorporating BrdU, DNA synthesis does not occur at sites of γH2AX foci. Furthermore activated ATM and Chk2 persist in these cells. We propose that the γH2AX foci in Chk1-depleted cells may represent sites of persistent replication fork damage or abandonment that are unable to resume DNA synthesis but do not play a direct role in the Chk1 suppressed death pathway.
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影响因子：
4.8
作者：
Furuta, T;Takemura, H;Pommier, Y
通讯作者：
Pommier, Y
影响因子：
56.9
作者：
Celeste, A;Petersen, S;Nussenzweig, A
通讯作者：
Nussenzweig, A
DOI：
10.1073/pnas.0603779103
发表时间：
2006-06-27
影响因子：
11.1
作者：
Marti, Thomas M.;Hefner, Eli;Cleaver, James E.
通讯作者：
Cleaver, James E.
影响因子：
3.5
作者：
Bolderson, E;Scorah, J;Meuth, M
通讯作者：
Meuth, M
影响因子：
12.4
作者：
Rodriguez, R.;Gagou, M. E.;Meuth, M.
通讯作者：
Meuth, M.