DNA damage-dependent nuclear dynamics of the Mre11 complex
DNA damage-dependent nuclear dynamics of the Mre11 complex
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DOI：
10.1128/mcb.21.1.281-288.2001
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发表时间：
2001-01-01
影响因子：
5.3
通讯作者：
Petrini, JHJ
中科院分区：
文献类型：
--
作者：
Mirzoeva, OK;Petrini, JHJ
Mre11复合物涉及细胞对DNA损伤反应的各个方面。我们使用人成纤维细胞的原位分级进行细胞学分析的Mre 11复合物蛋白的双链断裂（DSB）的反应。原位分离去除大多数核质蛋白，允许在诱导DNA损伤后变得更积极地结合到核结构的蛋白质的免疫荧光定位。我们发现，Mre 11复合物的一部分结合到未受损细胞中的早幼粒细胞白血病蛋白体上。γ射线照射后10分钟内，观察到Mre 11复合物在小颗粒灶中的核保留，并持续到2 h postirradiation。根据先前的证明，Mre 11复合物与电离辐射（IR）诱导的DSB相关，我们推断在这些条件下保留的蛋白质与DNA损伤相关。我们还观察到IR治疗后Rad51的保留增加，尽管IR诱导的Rad51病灶与Mre 11病灶不同。ATM激酶在S期检查点激活过程中磷酸化Nbs1，Mre 11复合物与DNA损伤无关。这些数据表明，Mre 11复合物在DSB反应中的功能隐含地依赖于其检测DNA损伤的能力。
The Mre11 complex has been implicated in diverse aspects of the cellular response to DNA damage. We used in situ fractionation of human fibroblasts to carry out cytologic analysis of Mre11 complex proteins in the double-strand break (DSB) response. In situ fractionation removes most nucleoplasmic protein, permitting immunofluorescent localization of proteins that become more avidly bound to nuclear structures after induction of DNA damage. We found that a fraction of the Mre11 complex was bound to promyelocyte leukemia protein bodies in undamaged cells. Within 10 min after gamma irradiation, nuclear retention of the Mre11 complex in small granular foci was observed and persisted until 2 h postirradiation. In light of the previous demonstration that the Mre11 complex associated with ionizing radiation (IR)-induced DSBs, we infer that the protein retained under these conditions was associated with DNA damage. We also observed increased retention of Rad51 following IR treatment, although IR induced Rad51 foci were distinct from Mre11 foci. The ATM kinase, which phosphorylates Nbs1 during activation of the S-phase checkpoint, was not required for the Mre11 complex to associate with DNA damage. These data suggest that the functions of the Mre11 complex in the DSB response are implicitly dependent upon its ability to detect DNA damage.