Impaired DNA replication prompts deletions within palindromic sequences, but does not induce translocations in human cells
Impaired DNA replication prompts deletions within palindromic sequences, but does not induce translocations in human cells
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DOI：
10.1093/hmg/ddp279
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发表时间：
2009-09-15
影响因子：
3.5
通讯作者：
Emanuel, Beverly S.
中科院分区：
文献类型：
--
作者：
Kurahashi, Hiroki;Inagaki, Hidehito;Emanuel, Beverly S.
在原核生物和真核生物中，回文区是不稳定的，容易被删除，这可能是由于复制的停滞或缓慢。在人类基因组中，它们似乎也部分或完全被删除，而两个富含at的回文重复序列（PATRR）有助于已知的反复出现的结构易位。为了探索导致人类回文不稳定性发展的机制，我们比较了人类细胞中PATRRs的新生易位和缺失的发生率。使用一种可以检测单个分子的高灵敏度PCR试验，在人类体细胞和精子中都没有检测到新生缺失。然而，在培养的细胞系中检测到低频率的缺失。通过给DNA聚合酶α 1 （POLA1）基因施用siRNA或引入POLA抑制剂来抑制DNA复制增加了频率。这与在类似条件下从未检测到的patrr介导的易位形成对比，但在人类精子样本中经常观察到。在前导链和滞后链合成过程中发现了进一步的缺失。我们的数据表明，停滞或缓慢的复制会导致PATRRs内的缺失，但其他机制可能会导致人类中patr介导的复发性易位。
Palindromic regions are unstable and susceptible to deletion in prokaryotes and eukaryotes possibly due to stalled or slow replication. In the human genome, they also appear to become partially or completely deleted, while two palindromic AT-rich repeats (PATRR) contribute to known recurrent constitutional translocations. To explore the mechanism that causes the development of palindrome instabilities in humans, we compared the incidence of de novo translocations and deletions at PATRRs in human cells. Using a highly sensitive PCR assay that can detect single molecules, de novo deletions were detected neither in human somatic cells nor in sperm. However, deletions were detected at low frequency in cultured cell lines. Inhibition of DNA replication by administration of siRNA against the DNA polymerase alpha 1 (POLA1) gene or introduction of POLA inhibitors increased the frequency. This is in contrast to PATRR-mediated translocations that were never detected in similar conditions but were observed frequently in human sperm samples. Further deletions were found to take place during both leading- and lagging-strand synthesis. Our data suggest that stalled or slow replication induces deletions within PATRRs, but that other mechanisms might contribute to PATRR-mediated recurrent translocations in humans.