CRISPR elements in Yersinia pestis acquire new repeats by preferential uptake of bacteriophage DNA, and provide additional tools for evolutionary studies
CRISPR elements in Yersinia pestis acquire new repeats by preferential uptake of bacteriophage DNA, and provide additional tools for evolutionary studies
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DOI：
10.1099/mic.0.27437-0
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发表时间：
2005-03-01
期刊：
影响因子：
2.8
通讯作者：
Vergnaud, G
中科院分区：
文献类型：
--
作者：
Pourcel, C;Salvignol, G;Vergnaud, G
被称为CRISPR（成簇的规律间隔的短回文重复序列）的显著重复元件由与非重复元件或“间隔区”间隔排列的重复序列组成。CRISPR存在于古菌和细菌中，与参与DNA重组和修复的基因相关。在鼠疫耶尔森氏菌基因组中，在三个不同的位点发现了三个此类元件，其中一个具有高度多态性。作者对鼠疫耶尔森氏菌的三个CRISPR总共109个等位基因进行了测序，并描述了29个新的间隔区，其中大多数是特定于一个分离株的。在9株假结核耶尔森氏菌中，发现了132个间隔区，其中只有3个在鼠疫耶尔森氏菌分离株中是常见的。在这里详细研究的东方型生物变种鼠疫耶尔森氏菌中，观察到基序的缺失，但似乎在一个共同的祖先元件上添加新基序是最常见的事件。这种情况发生在三个不同的位点，尽管在其中一个位点的发生率更高，而且新基序的添加是有极性的。有趣的是，发现最近获得的间隔区在基因组的另一个位点有同源物，其中大多数在一个不活跃的前噬菌体内部。据信这是首次对CRISPR元件中间隔区的起源进行了解释。CRISPR结构提供了一种新的、可靠的鉴定工具。
The remarkable repetitive elements called CRISPRs (clustered regularly interspaced short palindromic repeats) consist of repeats interspaced with non-repetitive elements or 'spacers'. CRISPRs are present in both archaea and bacteria, in association with genes involved in DNA recombination and repair. In the Yersinia pestis genome, three such elements are found at three distinct loci, one of them being highly polymorphic. The authors have sequenced a total of 109 alleles of the three Y. pestis CRISPRs and they describe 29 new spacers, most being specific to one isolate. In nine strains of Yersinia pseudo tuberculosis, 132 spacers were found, of which only three are common to Y. pestis isolates. In Y. pestis of the Orientalis biovar investigated in detail here, deletion of motifs is observed but it appears that addition of new motifs to a common ancestral element is the most frequent event. This takes place at the three different loci, although at a higher rate in one of the loci, and the addition of new motifs is polarized. Interestingly, the most recently acquired spacers were found to have a homologue at another locus in the genome, the majority of these inside an inactive prophage. This is believed to be the first time that the origin of the spacers in CRISPR elements has been explained. The CRISPR structure provides a new and robust identification tool.