Millennium Institute on Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
Laboratoire de Biologie et Pharmacologie Appliquée, Centre National de la Recherche Scientifique UMR 8113, École Normale Supérieure Paris-Saclay, Cachan, France.
Sci Rep. 2018 Jul 6;8(1):10292. doi: 10.1038/s41598-018-28537-0.
Genomic Islands (GIs) are DNA regions acquired through horizontal gene transfer that encode advantageous traits for bacteria. Many GIs harbor genes that encode the molecular machinery required for their excision from the bacterial chromosome. Notably, the excision/integration dynamics of GIs may modulate the virulence of some pathogens. Here, we report a novel family of GIs found in plant and animal Enterobacteriaceae pathogens that share genes with those found in ROD21, a pathogenicity island whose excision is involved in the virulence of Salmonella enterica serovar Enteritidis. In these GIs we identified a conserved set of genes that includes an excision/integration module, suggesting that they are excisable. Indeed, we found that GIs within carbapenem-resistant Klebsiella pneumoniae ST258 KP35 and enteropathogenic Escherichia coli O127:H6 E2348/69 are excised from the bacterial genome. In addition to putative virulence factors, these GIs encode conjugative transfer-related proteins and short and full-length homologues of the global transcriptional regulator H-NS. Phylogenetic analyses suggest that the identified GIs likely originated in phytopathogenic bacteria. Taken together, our findings indicate that these GIs are excisable and may play a role in bacterial interactions with their hosts.
基因岛（Genomic Islands，GIs）是通过水平基因转移获得的 DNA 区域，它们编码有利于细菌的有利特征。许多 GIs 携带有编码从细菌染色体上切除所需的分子机制的基因。值得注意的是，GIs 的切除/整合动态可能会调节一些病原体的毒力。在这里，我们报告了一类在植物和动物肠杆菌科病原体中发现的新型 GIs，它们与 ROD21 中发现的基因共享，ROD21 是一个致病性岛，其切除与肠炎沙门氏菌血清型肠炎亚种的毒力有关。在这些 GIs 中，我们鉴定出了一组保守的基因，包括一个切除/整合模块，这表明它们是可切除的。事实上，我们发现耐碳青霉烯类肺炎克雷伯菌 ST258 KP35 和肠致病性大肠杆菌 O127:H6 E2348/69 中的 GIs 从细菌基因组中被切除。除了假定的毒力因子外，这些 GIs 还编码了与接合转移相关的蛋白质以及全局转录调节因子 H-NS 的短全长同源物。系统发育分析表明，鉴定出的 GIs 可能起源于植物病原菌。综上所述，我们的研究结果表明，这些 GIs 是可切除的，可能在细菌与其宿主相互作用中发挥作用。
