CELL CYCLE-SPECIFIC CHANGES IN NUCLEOPROTEIN COMPLEXES AT A CHROMOSOMAL REPLICATION ORIGIN
CELL CYCLE-SPECIFIC CHANGES IN NUCLEOPROTEIN COMPLEXES AT A CHROMOSOMAL REPLICATION ORIGIN
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DOI：
10.1002/j.1460-2075.1995.tb00271.x
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发表时间：
1995-12-01
期刊：
影响因子：
11.4
通讯作者：
LEONARD, AC
中科院分区：
文献类型：
--
作者：
CASSLER, MR;GRIMWADE, JE;LEONARD, AC
DNA合成的起始是由蛋白质与复制起点的结合触发的，然而，对细胞周期中特定蛋白质与复制起点结合的顺序知之甚少。我们发现，在循环细胞中，至少有两种不同的核蛋白复合物在oriC。在细胞周期的大部分时间内，一种与倒位刺激因子（FIS）结合的核蛋白复合物在细胞启动DNA复制时转变为与整合宿主因子（IHF）结合的形式。与IHF的结合相一致，引发剂DnaA结合到其先前未被占据的R3位点。在稳定期，第三个核蛋白复合物形成。FIS是不存在的和无活性的oriC形成一个核蛋白结构，包含IHF，是没有观察到在循环细胞，我们建议FIS和IHF之间的相互作用，艾滋病组装的起始核蛋白复合物在细胞周期和块启动在不适当的时间。复制起点的这种组分交换让人想起酵母ARS 1复制前和复制后染色质状态之间的切换。
Initiation of DNA synthesis is triggered by the binding of proteins to replication origins, However, little is known about the order in which specific proteins associate with origin sites during the cell cycle. We show that in cycling cells there are at least two different nucleoprotein complexes at oriC. A factor for inversion stimulation (FIS)-bound nucleoprotein complex, present throughout the majority of the cell cycle, switches to an integration host factor (IHF)-bound form as cells initiate DNA replication. Coincident with binding of IHF, initiator DnaA binds to its previously unoccupied R3 site. In stationary phase, a third nucleoprotein complex forms. FIS is absent and inactive oriC forms a nucleoprotein structure containing IHF that is not observed in cycling cells, We propose that interplay between FIS and IHF aids assembly of initiation nucleoprotein complexes during the cell cycle and blocks initiation at inappropriate times. This exchange of components at replication origins is reminiscent of switching between pre- and post-replicative chromatin states at yeast ARS1.