Research Group for Host-Microbe Interactions, Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway.
Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.
mSphere. 2018 Nov 7;3(6):e00402-18. doi: 10.1128/mSphere.00402-18.
has a highly variable genome prone to recombination and horizontal gene transfer. Here, we have identified a novel genetic island with an insertion locus and mobilization genes similar to those of staphylococcus cassette chromosome elements SCC This novel element termed the enterococcus cassette chromosome (ECC) element was located in the 3' region of and encoded large serine recombinases similar to SCC Horizontal transfer of an ECC element termed ECC:: containing a knock-in chloramphenicol resistance determinant occurred in the presence of a conjugative plasmid. We determined the ECC:: insertion site in the 3' region of in the recipient by long-read sequencing. ECC:: also mobilized by homologous recombination through sequence identity between flanking insertion sequence (IS) elements in ECC:: and the conjugative plasmid. The genes were found in 69 of 516 genomes in GenBank. Full-length ECC elements were retrieved from 32 of these genomes. ECCs were flanked by and sites of approximately 50 bp. The sequences were found by PCR and sequencing of circularized ECCs in three strains. The genes in ECCs contained an amalgam of common and rare genes. Taken together, our data imply that ECC elements act as hot spots for genetic exchange and contribute to the large variation of accessory genes found in is a bacterium found in a great variety of environments, ranging from the clinic as a nosocomial pathogen to natural habitats such as mammalian intestines, water, and soil. They are known to exchange genetic material through horizontal gene transfer and recombination, leading to great variability of accessory genes and aiding environmental adaptation. Identifying mobile genetic elements causing sequence variation is important to understand how genetic content variation occurs. Here, a novel genetic island, the enterococcus cassette chromosome, is shown to contain a wealth of genes, which may aid in adapting to new environments. The transmission mechanism involves the only two conserved genes within ECC, , large serine recombinases that insert ECC into the host genome similarly to SCC elements found in staphylococci.
具有高度易变的基因组，易于重组和水平基因转移。在这里，我们鉴定了一个具有插入位点和移动基因的新型遗传岛，这些基因类似于葡萄球菌盒式染色体元件 SCC。这个新型元件称为肠球菌盒式染色体（ECC）元件，位于 3'区域，编码类似于 SCC 的大型丝氨酸重组酶。在存在可接合质粒的情况下，发生了一个称为 ECC::的 ECC 元件的水平转移，该元件含有一个氯霉素抗性决定簇的敲入。我们通过长读测序确定了 受体中 3'区域的 ECC::插入位点。ECC::也通过侧翼插入序列（IS）元件之间的序列同一性在 ECC::和可接合质粒之间通过同源重组进行了移动。在 GenBank 中的 516 个 基因组中，发现了 69 个 基因。从这些基因组中的 32 个中回收了全长 ECC 元件。ECC 元件被大约 50bp 的 和 位点侧翼。通过在三个菌株中对圆形化 ECC 进行 PCR 和测序，发现了 序列。ECC 中的基因包含常见和罕见 基因的混合物。总的来说，我们的数据表明，ECC 元件充当遗传交换的热点，并有助于 中发现的大量辅助基因的变异。 是一种在各种环境中发现的细菌，从临床医院的病原体到哺乳动物肠道、水和土壤等自然栖息地。它们通过水平基因转移和重组交换遗传物质，导致辅助基因的巨大变异，并有助于环境适应。鉴定导致序列变异的可移动遗传元件对于了解遗传内容变异的发生机制非常重要。在这里，展示了一个新型遗传岛，即肠球菌盒式染色体，它包含丰富的基因，这些基因可能有助于 适应新环境。传播机制涉及 ECC 中仅有的两个保守基因 和大型丝氨酸重组酶，它们类似于葡萄球菌中发现的 SCC 元件，将 ECC 插入宿主基因组。
