Palindrome regeneration by template strand-switching mechanism at the origin of DNA replication of porcine circovirus via the rolling-circle melting-pot replication model
Palindrome regeneration by template strand-switching mechanism at the origin of DNA replication of porcine circovirus via the rolling-circle melting-pot replication model
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DOI：
10.1128/jvi.78.17.9016-9029.2004
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发表时间：
2004-09-01
影响因子：
5.4
通讯作者：
Cheung, AK
中科院分区：
文献类型：
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作者：
Cheung, AK
据报道，位于DNA复制起点两侧的回文序列（反向重复序列）具有形成单链茎环十字形结构的潜力，对于许多原核和真核系统的环状基因组的复制至关重要。在这项研究中，猪圆环病毒的突变体基因组在起始侧翼回文序列中缺失，不能形成任何十字形结构，总是产生含有更长和更稳定回文序列的子代病毒。这些结果表明，起始侧翼回文是必不可少的终止，但不是启动DNA复制。在子代病毒中反向重复链中间的模板链转换的检测表明，负基因组和相应的回文链在DNA生物合成过程中同时充当模板，并支持最近提出的滚环“熔炉”复制模型。这个模型所呈现的基因组构型，一个四链的三级结构，提供了对DNA复制、反向重复序列校正（或转换）以及任何环状DNA分子与起始侧翼回文序列的非法重组的机制的见解。
Palindromic sequences (inverted repeats) flanking the origin of DNA replication with the potential of forming single-stranded stem-loop cruciform structures have been reported to be essential for replication of the circular genomes of many prokaryotic and eukaryotic systems. In this study, mutant genomes of porcine circovirus with deletions in the origin-flanking palindrome and incapable of forming any cruciform structures invariably yielded progeny viruses containing longer and more stable palindromes. These results suggest that origin-flanking palindromes are essential for termination but not for initiation of DNA replication. Detection of template strand switching in the middle of an inverted repeat strand among the progeny viruses demonstrated that both the minus genome and a corresponding palindromic strand served as templates simultaneously during DNA biosynthesis and supports the recently proposed rolling-circle "melting-pot" replication model. The genome configuration presented by this model, a four-stranded tertiary structure, provides insights into the mechanisms of DNA replication, inverted repeat correction (or conversion), and illegitimate recombination of any circular DNA molecule with an origin-flanking palindrome.