AUTHOR=Zhang Gang , Cui Qinna , Li Jianjuan , Guo Ruiliang , Leclercq Sébastien Olivier , Du Lifeng , Tang Na , Song Yuqin , Wang Chao , Zhao Fangqing , Feng Jie 

TITLE=The integrase of genomic island GIsul2 mediates the mobilization of GIsul2 and ISCR-related element CR2-sul2 unit through site-specific recombination

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.905865

DOI=10.3389/fmicb.2022.905865

ISSN=1664-302X

ABSTRACT=<p>In the worldwide health threat posed by antibiotic-resistant bacterial pathogens, mobile genetic elements (MGEs) play a critical role in favoring the dissemination of resistance genes. Among them, the genomic island GI<italic>sul2</italic> and the IS<italic>CR</italic>-related element CR2<italic>-sul2</italic> unit are believed to participate in this dissemination. However, the mobility of the two elements has not yet been demonstrated. Here, we found that the GI<italic>sul2</italic> and CR2<italic>-sul2</italic> units can excise from the host chromosomal attachment site (<italic>attB</italic>) in <italic>Shigella flexneri</italic>. Through establishing a two-plasmid mobilization system composed of a donor plasmid bearing the GI<italic>sul2</italic> and a trap plasmid harboring the <italic>attB</italic> in <italic>recA</italic>-deficient <italic>Escherichia coli</italic>, we reveal that the integrase of GI<italic>sul2</italic> can perform the excision and integration of GI<italic>sul2</italic> and CR2<italic>-sul2</italic> unit by site-specific recombination between <italic>att</italic> core sites. Furthermore, we demonstrate that the integrase and the <italic>att</italic> sites are required for mobility through knockout experiments. Our findings provide the first experimental characterization of the mobility of GI<italic>sul2</italic> and CR2<italic>-sul2</italic> units mediated by integrase. They also suggest a potential and unappreciated role of the GI<italic>sul2</italic> integrase family in the dissemination of CR2<italic>-sul2</italic> units carrying various resistance determinants in between.</p>