Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, Quebec, Canada G1V 0A6.
Nat Commun. 2013;4:2087. doi: 10.1038/ncomms3087.
Bacteria have developed a set of barriers to protect themselves against invaders such as phage and plasmid nucleic acids. Different prokaryotic defence systems exist and at least two of them directly target the incoming DNA: restriction-modification (R-M) and CRISPR-Cas systems. On their own, they are imperfect barriers to invasion by foreign DNA. Here, we show that R-M and CRISPR-Cas systems are compatible and act together to increase the overall phage resistance of a bacterial cell by cleaving their respective target sites. Furthermore, we show that the specific methylation of phage DNA does not impair CRISPR-Cas acquisition or interference activities. Taken altogether, both mechanisms can be leveraged to decrease phage contaminations in processes relying on bacterial growth and/or fermentation.
细菌已经开发出了一系列的屏障来保护自己免受噬菌体和质粒核酸等入侵者的侵害。不同的原核防御系统存在，其中至少有两种系统直接针对入侵的 DNA：限制修饰（R-M）和 CRISPR-Cas 系统。它们本身对于外来 DNA 的入侵是不完善的屏障。在这里，我们表明 R-M 和 CRISPR-Cas 系统是兼容的，并通过切割各自的靶位点共同作用，增加细菌细胞对噬菌体的整体抗性。此外，我们还表明噬菌体 DNA 的特定甲基化不会损害 CRISPR-Cas 的获取或干扰活性。总的来说，这两种机制都可以用来减少依赖细菌生长和/或发酵的过程中的噬菌体污染。
