Mobile genetic elements (MGEs) are key factors responsible for dissemination of virulence determinants and antimicrobial-resistance genes amongst pathogenic bacteria. Conjugative MGEs are notable for their high gene loads donated per transfer event, broad host ranges and phylogenetic ubiquity amongst prokaryotes, with the subclass of chromosomally inserted integrative and conjugative elements (ICEs) being particularly abundant. The focus on a small number of model systems has biased the study of ICEs towards those conferring readily selectable phenotypes to host cells, whereas the identification and characterization of integrated cryptic elements remains challenging. Even though antimicrobial resistance and horizontally acquired virulence genes are major factors aggravating neisserial infection, conjugative MGEs of Neisseria gonorrhoeae and Neisseria meningitidis remain poorly characterized. Using a phenotype-independent approach based on atypical distributions of DNA uptake sequences (DUSs) in MGEs relative to the chromosomal background, we have identified two groups of chromosomally integrated conjugative elements in Neisseria: one found almost exclusively in pathogenic species possibly deriving from the genus Kingella, the other belonging to a group of Neisseria mucosa-like commensals. The former element appears to enable transfer of traditionally gonococcal-specific loci such as the virulence-associated toxin-antitoxin system fitAB to N. meningitidis chromosomes, whilst the circular form of the latter possesses a unique attachment site (attP) sequence seemingly adapted to exploit DUS motifs as chromosomal integration sites. In addition to validating the use of DUS distributions in Neisseriaceae MGE identification, the >170 identified ICE sequences provide a valuable resource for future studies of ICE evolution and host adaptation.

中文翻译：

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通过DNA摄取序列方言的基因组分布鉴定致病性和共生奈瑟菌科物种中的整合和共轭元件。

流动遗传元件（MGE）是负责在致病细菌中传播毒力决定因素和抗微生物基因的关键因素。结合型MGE的显着之处在于每次转移事件中捐赠的高基因负荷，广泛的宿主范围和原核生物的系统发育普遍性，其中染色体插入的整合和结合型元件（ICE）的子类特别丰富。对少数模型系统的关注使ICEs的研究偏向那些赋予宿主细胞易于选择的表型的研究，而集成隐性元件的鉴定和表征仍然具有挑战性。即使抗菌素耐药性和水平获得性毒力基因是加重奈瑟菌感染的主要因素，淋病奈瑟氏球菌和脑膜炎奈瑟氏球菌的共轭MGEs仍然很差。使用基于表型相对于染色体背景的MGE中DNA摄取序列（DUS）的非典型分布的表型非依赖性方法，我们确定了奈瑟氏球菌中的两组染色体整合的结合元件：一组几乎仅存在于可能源自该属的病原体中Kingella，另一个属于一组类似奈瑟氏球菌的粘膜。前者似乎能够将传统的淋球菌特异性基因座（如毒力相关毒素-抗毒素系统fitAB）转移到脑膜炎奈瑟氏球菌染色体上，而后者的环状形式似乎具有一个独特的附着位点（attP）序列，似乎可以利用DUS主题作为染色体整合位点。