Duchossois Family Institute, University of Chicago, Chicago, IL, USA.
Department of Microbiology, University of Chicago, Chicago, IL, USA.
Science. 2024 Oct 25;386(6720):414-420. doi: 10.1126/science.adj9504. Epub 2024 Oct 24.
DNA transfer is ubiquitous in the human gut microbiota, especially among species of the order Bacteroidales. In silico analyses have revealed hundreds of mobile genetic elements shared between these species, yet little is known about the phenotypes they encode, their effects on fitness, or pleiotropic consequences for the recipient's genome. In this work, we show that acquisition of a ubiquitous integrative conjugative element (ICE) encoding a type VI secretion system (T6SS) shuts down the native T6SS of . Despite inactivating this T6SS, ICE acquisition increases the fitness of the transconjugant over its progenitor by arming it with the new T6SS. DNA transfer causes the strain to change allegiances so that it no longer targets ecosystem members with the same element yet is armed for communal defense.
DNA 转移在人类肠道微生物群中普遍存在，尤其是在拟杆菌目（Bacteroidales）的物种中。计算机分析揭示了这些物种之间存在数百种可移动遗传元件，但对于它们编码的表型、对适应性的影响，或对受体基因组的多效性后果知之甚少。在这项工作中，我们表明，一种普遍存在的整合性 conjugative 元件（ICE）的获得，该元件编码一种 VI 型分泌系统（T6SS），会关闭的天然 T6SS。尽管使这种 T6SS 失活，但 ICE 的获得通过赋予新的 T6SS，使 转导子的适应性比其亲本增加。DNA 转移导致菌株改变效忠关系，使其不再针对具有相同元件的生态系统成员，但为社区防御做好了武装。
