Different modes of spacer acquisition by the Staphylococcus epidermidis type III-A CRISPR-Cas system.
Different modes of spacer acquisition by the Staphylococcus epidermidis type III-A CRISPR-Cas system.
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DOI：
10.1093/nar/gkab1299
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发表时间：
2022-02-22
影响因子：
14.9
通讯作者：
Marraffini LA
中科院分区：
文献类型：
--
作者：
Aviram N;Thornal AN;Zeevi D;Marraffini LA
CRISPR-Cas系统为原核生物提供了一种获得感染免疫记忆的适应性防御机制。这是通过将入侵者（如噬菌体和质粒）基因组的短片段整合到宿主的CRISPR位点中来实现的。根据其遗传组成，CRISPR-Cas系统可分为六种类型，I- vi，然而，仅在I型和II型系统中广泛研究了间隔子获取。在没有噬菌体选择的情况下，我们在表皮葡萄球菌的III-A型CRISPR-Cas系统中使用诱导间隔物获取实验来研究这一过程。与I型和II型间隔片段获取类似，这种III型系统使用Cas1和Cas2优先整合来自染色体末端和DNA断裂后产生的游离dsDNA末端的间隔片段，这种方式被AddAB DNA修复复合体增强。令人惊讶的是，从rRNA和tRNA位点获得间隔序列的不同模式也被检测到，该模式仅跨越这些基因的转录序列，并且不被AddAB增强。因此，我们的研究结果揭示了可能在所有CRISPR-Cas系统中保守的共同机制原理，以及III型间隔物获取的独特和有趣的特征。
CRISPR-Cas systems provide prokaryotic organisms with an adaptive defense mechanism that acquires immunological memories of infections. This is accomplished by integration of short fragments from the genome of invaders such as phages and plasmids, called ‘spacers’, into the CRISPR locus of the host. Depending on their genetic composition, CRISPR-Cas systems can be classified into six types, I-VI, however spacer acquisition has been extensively studied only in type I and II systems. Here, we used an inducible spacer acquisition assay to study this process in the type III-A CRISPR-Cas system of Staphylococcus epidermidis, in the absence of phage selection. Similarly to type I and II spacer acquisition, this type III system uses Cas1 and Cas2 to preferentially integrate spacers from the chromosomal terminus and free dsDNA ends produced after DNA breaks, in a manner that is enhanced by the AddAB DNA repair complex. Surprisingly, a different mode of spacer acquisition from rRNA and tRNA loci, which spans only the transcribed sequences of these genes and is not enhanced by AddAB, was also detected. Therefore, our findings reveal both common mechanistic principles that may be conserved in all CRISPR-Cas systems, as well as unique and intriguing features of type III spacer acquisition.
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影响因子：
64.8
作者：
Goldberg, Gregory W.;Jiang, Wenyan;Bikard, David;Marraffini, Luciano A.
通讯作者：
Marraffini, Luciano A.
DOI：
10.1126/science.aaf5573
发表时间：
2016-08-05
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Abudayyeh OO;Gootenberg JS;Konermann S;Joung J;Slaymaker IM;Cox DB;Shmakov S;Makarova KS;Semenova E;Minakhin L;Severinov K;Regev A;Lander ES;Koonin EV;Zhang F
通讯作者：
Zhang F
影响因子：
64.5
作者：
Jiang W;Samai P;Marraffini LA
通讯作者：
Marraffini LA
影响因子：
64.8
作者：
Levy A;Goren MG;Yosef I;Auster O;Manor M;Amitai G;Edgar R;Qimron U;Sorek R
通讯作者：
Sorek R
影响因子：
4.8
作者：
Chedin, Frederic;Handa, Naofumi;Kowalczykowski, Stephen C.
通讯作者：
Kowalczykowski, Stephen C.