Microtubule Stress Modifies Intra-Nuclear Location of Msh2 in Mouse Embryonic Fibroblasts
Microtubule Stress Modifies Intra-Nuclear Location of Msh2 in Mouse Embryonic Fibroblasts
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微管应力改变小鼠胚胎成纤维细胞中 Msh2 的核内位置
DOI：
10.4161/cc.3.5.855
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发表时间：
2004
期刊：
影响因子：
4.3
通讯作者：
Paul J. Smith
中科院分区：
文献类型：
--
作者：
Nuria Marquez;S. Chappell;O. Sansom;A. Clarke;P. Teesdale‐Spittle;R. Errington;Paul J. Smith
通过错配修复（MMR）在有丝分裂和减数分裂周期中维持基因组稳定性需要MMR功能与多个过程的协调，包括细胞周期穿越、微管动力学的相关变化、染色质位点的蛋白质易位和检查点激活。我们研究了小鼠胚胎成纤维细胞（mef）中MMR蛋白Msh2在有丝分裂、秋碱破坏微管和顺式铂诱导DNA损伤时细胞内位置的变化。图像分析表明，mef在间期具有正常的高Msh2核保留，有丝分裂时蛋白质从染色质位点急剧分散到细胞质中。在顺铂和colcolid处理的间期mef中也观察到弥散，在整个细胞周期中，Msh2的总体水平没有任何变化。没有证据表明点状细胞质Msh2灶与任何微管结构共定位，并且敲除Msh2既不会改变微管破坏的程度，也不会改变colcemid对纺锤体组装检查点的功能激活。关键的是，蛋白的核外重新定位并没有改变msh2依赖性G2检查点延迟对顺铂诱导的DNA损伤的反应能力。通过利用荧光DNA结合探针DRAQ5新发现的碱基对偏好的共关联研究发现，在经历分散的细胞中，Msh2蛋白核池的耗损涉及蛋白质从富含at的染色质位点的快速重新定位。该研究揭示了MMR蛋白池在MEF细胞周期和对不同应激诱导剂的反应中意想不到的流动性。该结果首次将微管完整性与核内Msh2蛋白动力学联系起来。Msh2在间期mef中的高核保留与人类肿瘤细胞相反，而对蛋白质分散的观察表明，DNA损伤激活G2检查点只需要低水平的核定位Msh2。
The maintenance of genomic stability in mitotic and meiotic cycles through mismatch repair (MMR) demands the co-ordination of MMR functions with multiple processes including cell cycle traverse, linked changes in microtubule dynamics, protein translocation at chromatin sites and checkpoint activation. We have studied changes in the intracellular location of the MMR protein Msh2 in response to mitosis, microtubule disruption by colcemid and DNA damage induction by cis-platin in mouse embryonic fibroblasts (MEFs). Image analysis indicated that MEFs have a normally high nuclear retention of Msh2 during interphase with a precipitous dispersal of protein from chromatin sites into the cytoplasm at mitosis. Dispersal was also observed in cisplatin- and colcemid-treated interphase MEFs without any change in the overall Msh2 levels throughout the cell cycle. There was no evidence of co-localisation of the punctate cytoplasmic Msh2 foci with any microtubule structures and knockout of Msh2 altered neither the extent of microtubule disruption nor the functional activation of the spindle assembly checkpoint by colcemid. Critically, extra-nuclear relocation of protein did not alter the ability to mount an Msh2-dependent G2 checkpoint delay in response to cisplatin-induced DNA damage. Depletion of the nuclear pool of Msh2 protein in cells undergoing dispersal was found to involve a rapid relocation of protein from AT-rich chromatin sites as defined by co-association studies exploiting a newly-characterised base-pair preference of the fluorescent DNA binding probe DRAQ5. The study reveals the unexpected mobility of MMR protein pools during the MEF cell cycle and in response to different stress-inducing agents. The results link for the first time microtubule-integrity with intra-nuclear Msh2 protein dynamics. The high nuclear retention of Msh2 in interphase MEFs is in contrast to human tumour cells while the observations on protein dispersal suggest that only low levels of nuclear-located Msh2 are needed for G2 checkpoint activation by DNA damage.
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DOI：
--
发表时间：
1993
期刊：
European journal of histochemistry : EJH
影响因子：
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作者：
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影响因子：
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作者：
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影响因子：
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