title: Conjugative transfer of the integrative conjugative elements ICESt1 and ICESt3 from Streptococcus thermophilus.
abstract: Integrative and conjugative elements (ICEs), also called conjugative transposons, are genomic islands that excise, self-transfer by conjugation, and integrate in the genome of the recipient bacterium. The current investigation shows the intraspecies conjugative transfer of the first described ICEs in Streptococcus thermophilus, ICESt1 and ICESt3. Mitomycin C, a DNA-damaging agent, derepresses ICESt3 conjugative transfer almost 25-fold. The ICESt3 host range was determined using various members of the Firmicutes as recipients. Whereas numerous ICESt3 transconjugants of Streptococcus pyogenes and Enterococcus faecalis were recovered, only one transconjugant of Lactococcus lactis was obtained. The newly incoming ICEs, except the one from L. lactis, are site-specifically integrated into the 3' end of the fda gene and are still able to excise in these transconjugants. Furthermore, ICESt3 was retransferred from E. faecalis to S. thermophilus. Recombinant plasmids carrying different parts of the ICESt1 recombination module were used to show that the integrase gene is required for the site-specific integration and excision of the ICEs, whereas the excisionase gene is required for the site-specific excision only.
authors.affiliation: Laboratoire de Génétique et Microbiologie UMR INRA-UHP 1128, IFR110, Faculté des Sciences et Techniques, Nancy-Université, BP 239, 54506 Vandoeuvre-lès-Nancy, France. guedon@nancy.inra.fr
authors.forename: Xavier
authors.initials: X
authors.lastname: Bellanger
authors.forename: Adam P
authors.initials: AP
authors.lastname: Roberts
authors.forename: Catherine
authors.initials: C
authors.lastname: Morel
authors.forename: Frédéric
authors.initials: F
authors.lastname: Choulet
authors.forename: Guillaume
authors.initials: G
authors.lastname: Pavlovic
authors.forename: Peter
authors.initials: P
authors.lastname: Mullany
authors.forename: Bernard
authors.initials: B
authors.lastname: Decaris
authors.forename: Gérard
authors.initials: G
authors.lastname: Guédon
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D003227:Conjugation, Genetic; D004249:DNA Damage; D013293:Enterococcus faecalis / Q000235:genetics; D022761:Gene Transfer, Horizontal; D020071:Interspersed Repetitive Sequences; D013294:Lactococcus lactis / Q000235:genetics; D016685:Mitomycin / Q000494:pharmacology; D011995:Recombination, Genetic; D013297:Streptococcus pyogenes / Q000235:genetics; D048249:Streptococcus thermophilus / Q000235:genetics*
chemical_list: D000477:Alkylating Agents; D016685:Mitomycin