Wang K, Xu F Y, Ahern K G, Pearson G D
Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331.
Virology. 1991 Jul;183(1):44-51. doi: 10.1016/0042-6822(91)90116-s.
Adenovirus DNA initiates strand-displacement replication from origins located in identical inverted terminal repetitions (ITRs). Panhandle structures, formed by base pairing between ITRs on the displaced strands, have been proposed as replication intermediates for complementary strand synthesis. We have used a model system, which separates adenovirus replication origin sequences from those involved in panhandle formation, to study the length and sequence integrity of panhandles. By making a series of unidirectional deletion in the panhandle sequence, we show that 31 bp are necessary for panhandle formation. Removal of long stretches of 3'-unpaired nucleotides distal to the panhandle is extremely efficient. Our results argue for the formation of panhandles during adenovirus DNA replication and provide a mechanism for maintaining sequence identity between distantly located inverted repetitions. The size constraint may explain why the adenovirus ITRs are larger than the viral DNA replication origins.
腺病毒DNA从位于相同反向末端重复序列（ITR）中的起始位点启动链置换复制。由置换链上的ITR之间碱基配对形成的锅柄结构已被认为是互补链合成的复制中间体。我们使用了一个模型系统，该系统将腺病毒复制起始序列与参与锅柄形成的序列分开，以研究锅柄的长度和序列完整性。通过在锅柄序列中进行一系列单向缺失，我们表明锅柄形成需要31个碱基对。去除锅柄远端长段的3'-未配对核苷酸非常有效。我们的结果支持腺病毒DNA复制过程中锅柄的形成，并提供了一种机制来维持远距离反向重复序列之间的序列同一性。大小限制可能解释了为什么腺病毒ITR比病毒DNA复制起始位点更大。
