DNA motifs determining the accuracy of repeat duplication during CRISPR adaptation in Haloarcula hispanica.
DNA motifs determining the accuracy of repeat duplication during CRISPR adaptation in Haloarcula hispanica.
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DNA 基序决定西班牙 Haloarcula CRISPR 适应过程中重复复制的准确性
DOI：
10.1093/nar/gkw260
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发表时间：
2016-05-19
影响因子：
14.9
通讯作者：
Xiang H
中科院分区：
文献类型：
--
作者：
Wang R;Li M;Gong L;Hu S;Xiang H
成簇规则间隔短回文重复序列（CRISPR）获得新的间隔区以在原核生物中产生适应性免疫。在间隔区整合过程中，前导重复总是准确地复制，导致重复长度标尺的推测。在这里，在Haloarcula hispanica，我们证明了它的30-bp重复的准确复制需要两个保守的中间重复基序，AACCC和GTGGG。AACCC基序是必不可少的，需要在前导重复连接位点下游10 bp处，重复始终开始。有趣的是，重复重复终止序列独立，通常与GTGGG基序，这似乎是作为一个锚网站的分子统治者的特定距离。因此，改变两个基序之间的间隔导致异常的重复大小（29、31、32或33 bp）。我们提出适应复合物可以识别这些中间重复元件，以能够测量重复DNA的间隔区整合。
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) acquire new spacers to generate adaptive immunity in prokaryotes. During spacer integration, the leader-preceded repeat is always accurately duplicated, leading to speculations of a repeat-length ruler. Here in Haloarcula hispanica, we demonstrate that the accurate duplication of its 30-bp repeat requires two conserved mid-repeat motifs, AACCC and GTGGG. The AACCC motif was essential and needed to be ∼10 bp downstream from the leader-repeat junction site, where duplication consistently started. Interestingly, repeat duplication terminated sequence-independently and usually with a specific distance from the GTGGG motif, which seemingly served as an anchor site for a molecular ruler. Accordingly, altering the spacing between the two motifs led to an aberrant duplication size (29, 31, 32 or 33 bp). We propose the adaptation complex may recognize these mid-repeat elements to enable measuring the repeat DNA for spacer integration.