Palindromic sequences in DNA can instigate genetic recombination and genome instability, which can result in devastating conditions such as the Emmanuel syndrome. Palindrome recombinogenicity increases with its size and sequence similarity between palindrome arms, while quasipalindromes with long spacers are less recombinogenic. However, the minimal spacer length, which could reduce or abolish palindrome recombinogenicity in the eukaryotic genome, was never determined. Therefore, we constructed a series of palindromes containing spacers of lengths ranging from 0 (perfect palindrome) to 10 bp and tested their recombinogenicity in yeast Saccharomyces cerevisiae. We found that a 7 bp spacer significantly reduces 126 bp palindrome recombinogenicity, while a 10 bp spacer completely stabilizes palindromes up to 150 bp long. Additionally, we showed that palindrome stimulated recombination rate is not dependent on Mus81 and Yen1 endonucleases. We also compared the recombinogenicity of a perfect 126 bp palindrome and a corresponding quasipalindrome consisting of the same palindrome arms with a stabilising 10 bp spacer in sgs1Δ and rad27Δ backgrounds, since both Sgs1 helicase and Rad27 endonuclease are implicated in preventing hairpin formation at palindromic sequences during replication.

中文翻译：

---

短间隔子对回文重组能力的大小依赖性抗重组作用。

DNA中的回文序列会引发基因重组和基因组不稳定，从而可能导致毁灭性疾病，例如伊曼纽尔综合征。回文的重组发生力随着回文臂之间的大小和序列相似性的增加而增加，而具有长间隔的准回文发生重组的可能性较小。然而，从未确定最小间隔区长度，该最小间隔区长度可减少或消除真核基因组中的回文重组。因此，我们构建了一系列长度为0（完美回文）至10 bp间隔的回文，并测试了它们在酿酒酵母中的重组能力。我们发现，一个7 bp的间隔子可显着降低126 bp的回文重组能力，而10 bp的间隔子可完全稳定长达150 bp的回文。另外，我们表明回文刺激的重组率不依赖于Mus81和Yen1核酸内切酶。我们还比较了在sgs1Δ和rad27Δ背景下，一个完美的126 bp回文和一个由相同回文臂和一个稳定的10 bp间隔组成的准回文的重组能力，因为Sgs1解旋酶和Rad27核酸内切酶均涉及回文序列期间防止发夹形成复制。