Epstein-Barr Nuclear Antigen 1 modulates replication of oriP-plasmids by impeding replication and transcription fork migration through the family of repeats.
Epstein-Barr Nuclear Antigen 1 modulates replication of oriP-plasmids by impeding replication and transcription fork migration through the family of repeats.
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DOI：
10.1186/1743-422x-6-29
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发表时间：
2009-03-05
期刊：
影响因子：
4.8
通讯作者：
Luftig RB
中科院分区：
文献类型：
--
作者：
Aiyar A;Aras S;Washington A;Singh G;Luftig RB
爱泼斯坦-巴尔病毒（EB病毒）在每个细胞周期复制一次，并在潜伏感染的细胞中均匀分配。这两个过程都需要一个单一的病毒顺式作用元件，即oriP，以及一种单一的病毒蛋白，即EBNA1。EBNA1与oriP中的两组结合位点结合，这两组位点分别被称为二元对称元件（DS）和重复序列家族（FR），它们分别作为复制元件和分配元件发挥作用。野生型FR包含20个EBNA1结合位点。
我们和其他研究人员此前已确定，减少FR中EBNA1结合位点的数量会提高oriP质粒的复制效率。在此我们证明，FR中野生型数量的结合位点会阻碍复制叉和转录叉的移动。此外，将FR分成两组相距较远、每组十个结合位点的序列，会使oriP质粒在表达EBNA1的细胞中稳定存在的效率提高十倍。我们还确定，结合在FR上的EBNA1会以一种依赖于FR中EBNA1结合位点数量的方式损害转录叉的移动。
我们得出结论，结合在FR上的EBNA1通过阻碍复制叉的移动来调节oriP质粒的复制。结合FR后，EBNA1还会阻止转录叉的移动。因此，除了调节oriP的复制外，结合在FR上的EBNA1还降低了两个相对的复制叉之间，或转录叉与复制叉之间发生有害碰撞的可能性。
Epstein-Barr virus is replicated once per cell-cycle, and partitioned equally in latently infected cells. Both these processes require a single viral cis-element, termed oriP, and a single viral protein, EBNA1. EBNA1 binds two clusters of binding sites in oriP, termed the dyad symmetry element (DS) and the family of repeats (FR), which function as a replication element and partitioning element respectively. Wild-type FR contains 20 binding sites for EBNA1. We, and others, have determined previously that decreasing the number of EBNA1-binding sites in FR increases the efficiency with which oriP-plasmids are replicated. Here we demonstrate that the wild-type number of binding sites in FR impedes the migration of replication and transcription forks. Further, splitting FR into two widely separated sets of ten binding sites causes a ten-fold increase in the efficiency with which oriP-plasmids are established in cells expressing EBNA1. We have also determined that EBNA1 bound to FR impairs the migration of transcription forks in a manner dependent on the number of EBNA1-binding sites in FR. We conclude that EBNA1 bound to FR regulates the replication of oriP-plasmids by impeding the migration of replication forks. Upon binding FR, EBNA1 also blocks the migration of transcription forks. Thus, in addition to regulating oriP replication, EBNA1 bound to FR also decreases the probability of detrimental collisions between two opposing replication forks, or between a transcription fork and a replication fork.