Andalusian Centre for Developmental Biology (CABD, UPO-CSIC-JA), Faculty of Experimental Sciences (Genetics Department), University Pablo de Olavide, 41013 Seville, Spain.
Faculty of Biology, Johannes Gutenberg-Universität Mainz, Biozentrum I, Hans-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany.
Sci Adv. 2023 Mar 24;9(12):eadd8911. doi: 10.1126/sciadv.add8911.
CRISPR-Cas systems are prokaryotic acquired immunity mechanisms, which are found in 40% of bacterial genomes. They prevent viral infections through small DNA fragments called spacers. However, the vast majority of these spacers have not yet been associated with the virus they recognize, and it has been named CRISPR dark matter. By analyzing the spacers of tens of thousands of genomes from six bacterial species, we have been able to reduce the CRISPR dark matter from 80% to as low as 15% in some of the species. In addition, we have observed that, when a genome presents CRISPR-Cas systems, this is accompanied by particular sets of membrane proteins. Our results suggest that when bacteria present membrane proteins that make it compete better in its environment and these proteins are, in turn, receptors for specific phages, they would be forced to acquire CRISPR-Cas.
CRISPR-Cas 系统是原核生物获得性免疫机制，存在于 40%的细菌基因组中。它们通过称为间隔序列的小 DNA 片段来防止病毒感染。然而，这些间隔序列中绝大多数尚未与它们所识别的病毒相关联，这些序列被称为 CRISPR 暗物质。通过分析来自六个细菌物种的数万个基因组的间隔序列，我们已经能够将一些物种中的 CRISPR 暗物质从 80%降低到低至 15%。此外，我们观察到，当基因组呈现 CRISPR-Cas 系统时，这伴随着特定的膜蛋白集。我们的结果表明，当细菌呈现出使其在环境中更具竞争力的膜蛋白，并且这些蛋白反过来又是特定噬菌体的受体时，它们将被迫获得 CRISPR-Cas。
