發(fā)布者：抗性基因網(wǎng) 時間：2023-06-12 瀏覽量：453
摘要
? ? ? 質(zhì)粒可以通過接合在細胞之間轉(zhuǎn)移，從而通過水平基因轉(zhuǎn)移驅(qū)動細菌進化。然而，我們忽略了許多質(zhì)粒轉(zhuǎn)移的分子機制，因為它們?nèi)狈Y(jié)合所需的所有蛋白質(zhì)編碼基因。我們通過在大腸桿菌和金黃色葡萄球菌中鑒定數(shù)百個具有結(jié)合轉(zhuǎn)移來源的質(zhì)粒和染色體，解決了這個難題。這些質(zhì)粒（pOriT）劫持了偶聯(lián)或可移動元件的松弛酶，但不是兩者都劫持。pOriT和其他質(zhì)粒之間的功能依賴性解釋了它們的共存：pOriT在具有許多質(zhì)粒的細胞中豐富，而結(jié)合質(zhì)粒在其他質(zhì)粒中最常見。我們系統(tǒng)地描述了與接合和替代轉(zhuǎn)移機制有關(guān)的質(zhì)粒遷移率，現(xiàn)在可以提出其中約90%的假定轉(zhuǎn)移機制。在大多數(shù)情況下，質(zhì)粒的遷移似乎涉及結(jié)合。有趣的是，遷移機制是質(zhì)粒編碼的附屬性狀的重要決定因素，因為pOriTs具有最高密度的抗微生物抗性基因，而缺乏假定轉(zhuǎn)移機制的質(zhì)粒具有最低密度。我們闡明了質(zhì)粒之間的進化關(guān)系，并表明許多pOriT可能是由其他類型質(zhì)粒中的基因缺失引起的。這些結(jié)果表明，大多數(shù)質(zhì)?？梢酝ㄟ^接合轉(zhuǎn)移。
Abstract
Plasmids can be transferred between cells by conjugation, thereby driving bacterial evolution by horizontal gene transfer. Yet, we ignore the molecular mechanisms of transfer for many plasmids because they lack all protein-coding genes required for conjugation. We solved this conundrum by identifying hundreds of plasmids and chromosomes with conjugative origins of transfer in Escherichia coli and Staphylococcus aureus. These plasmids (pOriT) hijack the relaxases of conjugative or mobilizable elements, but not both. The functional dependencies between pOriT and other plasmids explain their co-occurrence: pOriT are abundant in cells with many plasmids, whereas conjugative plasmids are the most common in the others. We systematically characterized plasmid mobility in relation to conjugation and alternative mechanisms of transfer and can now propose a putative mechanism of transfer for ～90% of them. In most cases, plasmid mobility seems to involve conjugation. Interestingly, the mechanisms of mobility are important determinants of plasmid-encoded accessory traits, since pOriTs have the highest densities of antimicrobial resistance genes, whereas plasmids lacking putative mechanisms of transfer have the lowest. We illuminate the evolutionary relationships between plasmids and suggest that many pOriT may have arisen by gene deletions in other types of plasmids. These results suggest that most plasmids can be transferred by conjugation.
https://academic.oup.com/nar/article/51/7/3001/6849495?login=false