SeqA blocking of DnaA-oriC interactions ensures staged assembly of the E. coli pre-RC.
SeqA blocking of DnaA-oriC interactions ensures staged assembly of the E. coli pre-RC.
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DOI：
10.1016/j.molcel.2006.09.016
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发表时间：
2006-11
期刊：
影响因子：
16
通讯作者：
Christian J. Nievera;J. Torgue;J. Grimwade;A. Leonard
中科院分区：
文献类型：
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作者：
Christian J. Nievera;J. Torgue;J. Grimwade;A. Leonard
DnaA在E中仅占据三个最高亲和力的结合位点。coli oriC在大部分细胞周期中表达。在染色体复制开始之前，DNA A与额外的识别位点相互作用，导致局部DNA链分离。在细胞周期中形成的这两种DnaA-oriC复合物在功能上和时间上类似于酵母ORC和pre-RC。起始后，SeqA与半甲基化的oriC结合，隔离oriC，同时活性DnaA的水平降低，防止重新起始。在本文中，我们研究如何重置oforiC的ORC样复合物是协调与SeqA介导的隔离。我们报告说，在隔离期间，ORICresets到ORC。这是可能的，因为SeqA阻断了DnaA与半甲基化oriConly在与GATC相关的低亲和力识别位点的结合，但不干扰高亲和力位点的占据。因此，在隔离期间，SeqA抑制了前RC组装，同时确保E的重置。coliORC。
DnaA occupies only the three highest-affinity binding sites inE. coli oriCthroughout most of the cell cycle. Immediately prior to initiation of chromosome replication, DnaA interacts with additional recognition sites, resulting in localized DNA-strand separation. These two DnaA-oriCcomplexes formed during the cell cycle are functionally and temporally analogous to yeast ORC and pre-RC. After initiation, SeqA binds to hemimethylatedoriC, sequesteringoriCwhile levels of active DnaA are reduced, preventing reinitiation. In this paper, we investigate how resetting oforiCto the ORC-like complex is coordinated with SeqA-mediated sequestration. We report thatoriCresets to ORC during sequestration. This was possible because SeqA blocked DnaA binding to hemimethylatedoriConly at low-affinity recognition sites associated with GATC but did not interfere with occupation of higher-affinity sites. Thus, during the sequestration period, SeqA repressed pre-RC assembly while ensuring resetting ofE. coliORC.