The E1 helicase of human papillomavirus type 11 binds to the origin of replication with low sequence specificity
The E1 helicase of human papillomavirus type 11 binds to the origin of replication with low sequence specificity
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DOI：
10.1006/viro.2000.0204
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发表时间：
2000-05-10
期刊：
影响因子：
3.7
通讯作者：
Phelps, WC
中科院分区：
文献类型：
--
作者：
Dixon, EP;Pahel, GL;Phelps, WC
人乳头瘤病毒 11 型 E1 和 E2 基因的表达对于支持病毒 DNA 复制是必要且充分的。全长 E2 蛋白是一种转录调节剂，还与 E1 解旋酶相互作用，在病毒复制起点形成 E1/E2 复合物。先前的研究表明，该复合物与复制起点的有效结合是位点特异性的，并且 E2 同二聚体是 E1 有效结合所必需的。人乳头瘤病毒 11 型 E2 和 E1 蛋白已被纯化，并且它们与 HPV 11 型病毒复制起点的协同结合已得到表征。已证明 E1 与 HPV 11 型复制起点的低亲和力结合很大程度上是非特异性的。 E1 结合 DNA 不需要与 E2 形成复合物，并且似乎独立于 ATP 结合或水解。随着 E2 数量的增加，E1 结合数量增加，E2 结合位点的突变证明 E2BS 位点是 E1 和 E2 在复制起点特异性结合为高亲和力复合物所必需的。通过突变对富含 A/T 的 E1 结合位点进行分析表明，它对于高亲和力 E1/E2 复合物的形成不是必需的。因此，尽管动物和人乳头瘤病毒之间的复制功能得到了很好的保守，但 E1 的 DNA 结合要求存在细微差异，这可能预示着各种乳头瘤病毒类型的 DNA 复制系统之间存在机制差异。 (C) 2000 年学术出版社。
Expression of the human papillomavirus type 11 E1 and E2 genes is necessary and sufficient to support viral DNA replication. The full-length E2 protein is a transcriptional modulator that also interacts with the E1 helicase to form an E1/E2 complex at the viral origin of replication. Previous studies indicated that efficient binding of this complex to the replication origin is site-specific and that the E2 homodimer was required for efficient E1 binding. Human papillomavirus type 11 E2 and E1 proteins have been purified and their cooperative binding to the HPV type 11 viral replication origin has been characterized. Low-affinity E1 binding to the HPV type 11 replication origin was demonstrated and found to be largely nonspecific. DNA binding by E1 does not require complex formation with E2 and appears to be independent of ATP binding or hydrolysis. E1 binding quantitatively increased with the addition of increasing amounts of E2 and mutations in the E2 binding site demonstrated that the E2BS site is required for E1 and E2 to specifically bind as a high-affinity complex at the replication origin. Analysis of the A/T-rich E1 binding site via mutation showed that it was nonessential for high-affinity E1/E2 complex formation. Thus, although the replication functions between the animal and the human papillomaviruses are well conserved, there are subtle differences in the DNA binding requirements for E1, which may portend mechanistic differences among the DNA replication systems of various papillomavirus types. (C) 2000 Academic Press.