Replisome assembly at oriC, the replication origin of E-coli, reveals an explanation for initiation sites outside an origin
Replisome assembly at oriC, the replication origin of E-coli, reveals an explanation for initiation sites outside an origin
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DOI：
10.1016/s1097-2765(00)80205-1
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发表时间：
1999-10-01
期刊：
影响因子：
16
通讯作者：
O'Donnell, M
中科院分区：
文献类型：
--
作者：
Fang, LH;Davey, MJ;O'Donnell, M
这项研究概述了下游事件的起源解旋的DnaA，导致组装的两个复制叉在E。coli origin，oriC.我们发现，两个六聚体的DnaB组装到所产生的泡沫的相对链，进一步扩大它，但解旋酶的行动是不需要的。引物酶直到解旋酶移动65个核苷酸或更多才起作用。一旦引物形成，两个大的DNA聚合酶III全酶机器分子组装成气泡，形成两个复制叉。引物的位置是异质的，有些甚至在oriC之外。这一观察结果适用于许多系统，原核和真核。不均匀的起始位点很可能是由引发酶与移动解旋酶靶标一起发挥作用来解释的。
This study outlines the events downstream of origin unwinding by DnaA, leading to assembly of two replication forks at the E. coli origin, oriC. We show that two hexamers of DnaB assemble onto the opposing strands of the resulting bubble, expanding it further, yet helicase action is not required. Primase cannot act until the helicases move 65 nucleotides or more. Once primers are formed, two molecules of the large DNA polymerase III holoenzyme machinery assemble into the bubble, forming two replication forks. Primer locations are heterogeneous; some are even outside oriC. This observation generalizes to many systems, prokaryotic and eukaryotic. Heterogeneous initiation sites are likely explained by primase functioning with a moving helicase target.