The Initiator Protein DnaA Contributes to Keeping New Origins Inactivated by Promoting the Presence of Hemimethylated DNA
The Initiator Protein DnaA Contributes to Keeping New Origins Inactivated by Promoting the Presence of Hemimethylated DNA
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DOI：
10.1016/j.jmb.2008.09.042
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发表时间：
2008-12-31
影响因子：
5.6
通讯作者：
Skarstad, Kirsten
中科院分区：
文献类型：
--
作者：
Bach, Trond Morigen;Skarstad, Kirsten
大肠杆菌复制起点oriC和其他具有高数量GATC位点的区域在复制后保持半甲基化的时间比具有平均数量GATC位点的区域长得多。半甲基化的延长期归因于结合的SeqA蛋白的存在。在此，发现在datA位点插入的GATC簇（其在体内结合大量DnaA）根本没有被再甲基化，除非DnaA蛋白的可用性严重降低。还发现oriC的螯合受到DnaA可用性的影响。在DnaA的可用性减少后，起源半甲基化的时期减少了约30%。结果表明，不仅SeqA结合，而且DnaA结合到新复制的起点有助于保持它们的半甲基化。还发现，在GATC：：datA簇处具有DnaA介导的保护和隔离的组合的细胞中，SeqA焦点的数量增加。(C)2008爱思唯尔有限公司保留所有权利。
The Escherichia coli replication origin oriC and other regions with high numbers of GATC sites remain hemimethylated after replication much longer than regions with average numbers of GATC sites. The prolonged period of hemimethylation has been attributed to the presence of bound SeqA protein. Here, it was found that a GATC cluster inserted at the datA site, which binds large amounts of DnaA in vivo, did not become remethylated at all, unless the availability of the DnaA protein was severely reduced. Sequestration of oriC was also found to be affected by the availability of DnaA. The period of origin hemimethylation was reduced by similar to 30% upon a reduction in the availability of DnaA. The result shows that not only SeqA binding but also DnaA binding to newly replicated origins contributes to keeping them hemimethylated. It was also found that the number of SeqA foci increased in cells with a combination of DnaA-mediated protection and sequestration at the GATC: :datA cluster. (C) 2008 Elsevier Ltd. All rights reserved.