Mobilization of IMEs Integrated in the oriT of ICEs Involves Their Own Relaxase Belonging to the Rep-Trans Family of Proteins

• Published in: Genes 2020-08, Vol.11 (9), p.1004
• Main Authors: Libante, Virginie, Sarica, Nazim, Mohamad Ali, Abbas, Gapp, Chloé, Oussalah, Anissa, Guédon, Gérard, Leblond-Bourget, Nathalie, Payot, Sophie
• Format: Article
• Language: English
• Subjects: Antibiotic resistance; Antibiotics; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biochemistry, Molecular Biology; Chromosomes, Bacterial - genetics; Conjugation, Genetic; Deoxyribonucleic acid; DNA; DNA Transposable Elements; Drug resistance; Endodeoxyribonucleases - genetics; Endodeoxyribonucleases - metabolism; Experiments; Genes; Genetic transformation; Genomes; Genomics; Gram-negative bacteria; Gram-positive bacteria; Humans; Integrases - genetics; Integrases - metabolism; Interspersed Repetitive Sequences; Life Sciences; Mobile genetic elements; Observations; Phylogeny; Physiological aspects; Plasmids; Proteins; Recombination; Relaxase; Streptococcus - classification; Streptococcus - genetics; Streptococcus - metabolism; Streptococcus infections
• ISSN: 2073-4425; 2073-4425
• DOI: 10.3390/genes11091004

Integrative mobilizable elements (IMEs) are widespread but very poorly studied integrated elements that can excise and hijack the transfer apparatus of co-resident conjugative elements to promote their own spreading. Sixty-four putative IMEs, harboring closely related mobilization and recombination modules, were found in 14 species and in . Fifty-three are integrated into the origin of transfer ( ) of a host integrative conjugative element (ICE), encoding a MobT relaxase and belonging to three distant families: ICE , Tn , and ICE . The others are integrated into an unrelated IME or in chromosomal sites. After labeling by an antibiotic resistance gene, the conjugative transfer of one of these IMEs (named IME_ ) and its host ICE was measured. Although the IME is integrated in an ICE, it does not transfer as a part of the host ICE (no -mobilization). The IME excises and transfers separately from the ICE (without impacting its transfer rate) using its own relaxase, distantly related to all known MobT relaxases, and integrates in the of the ICE after transfer. Overall, IME_ use MobT-encoding ICEs both as hosts and as helpers for conjugative transfer. As half of them carry (C), they actively participate in the dissemination of lincosamide-streptogramin A-pleuromutilin resistance among Firmicutes.