Cdt1 associates dynamically with chromatin throughout G1 and recruits Geminin onto chromatin
Cdt1 associates dynamically with chromatin throughout G1 and recruits Geminin onto chromatin
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DOI：
10.1038/sj.emboj.7601597
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
G. Xouri;A. Squire;M. Dimaki;Bart Geverts;P. Verveer;S. Taraviras;H. Nishitani;A. Houtsmuller;P. Bastiaens;Z. Lygerou
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文献类型：
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作者：
G. Xouri;A. Squire;M. Dimaki;Bart Geverts;P. Verveer;S. Taraviras;H. Nishitani;A. Houtsmuller;P. Bastiaens;Z. Lygerou
为了维持基因组的完整性，真核细胞在有丝分裂末期和G1期在染色质上组装预复制复合体（preRCs）后，每个细胞周期启动一次DNA复制。在S期，prcs被分解，阻止了另一轮复制的启动。Cdt1是prc的关键成员，通过蛋白水解及其抑制剂Geminin对其进行正确调控对于防止过早的再复制至关重要。利用定量荧光显微镜，我们研究了活细胞中Cdt1与染色质和双链蛋白的相互作用。我们发现Cdt1在G1期表现出与染色质的动态相互作用，并且负责染色质和双子座相互作用的蛋白质结构域是可分离的。与现有的体外数据相反，我们发现Cdt1在体内同时结合Geminin和染色质，从而将Geminin招募到染色质上。我们提出cdt1 -染色质的动态关联和Geminin在染色质上的招募为许可过程提供了时空控制。
To maintain genome integrity, eukaryotic cells initiate DNA replication once per cell cycle after assembling prereplicative complexes (preRCs) on chromatin at the end of mitosis and during G1. In S phase, preRCs are disassembled, precluding initiation of another round of replication. Cdt1 is a key member of the preRC and its correct regulation via proteolysis and by its inhibitor Geminin is essential to prevent premature re‐replication. Using quantitative fluorescence microscopy, we study the interactions of Cdt1 with chromatin and Geminin in living cells. We find that Cdt1 exhibits dynamic interactions with chromatin throughout G1 phase and that the protein domains responsible for chromatin and Geminin interactions are separable. Contrary to existingin vitrodata, we show that Cdt1 simultaneously binds Geminin and chromatinin vivo, thereby recruiting Geminin onto chromatin. We propose that dynamic Cdt1–chromatin associations and the recruitment of Geminin to chromatin provide spatio‐temporal control of the licensing process.