title: Analysis and identification of IS1548 insertion targets in Streptococcus agalactiae.
abstract: The prevalence of the insertion sequence IS1548 is strongly linked to clonal complex 19 Streptococcus agalactiae strains associated with neonatal meningitis and endocarditis. We previously reported that IS1548 insertion upstream of lmb is involved in stronger binding of a S. agalactiae meningitic strain to laminin. A few other IS1548 insertion sites were also identified by others. In this study, we analyzed IS1548 described target sites in S. agalactiae and showed that most of them are linked to zinc-responsive genes. Moreover, we identified two not yet described IS1548 insertion sites in the adcRCB operon encoding the main regulator of zinc homeostasis and subunits of a zinc ABC transporter. We also identified two conserved motifs of 8 and 10 bp close to IS1548 insertion sites. These motifs representing potential IS1548 targets were found upstream of several S. agalactiae ORFs. One of these predicted IS1548 targets was validated experimentally, allowing the identification of an IS1548 insertion site upstream of murB in all of the clonal complex 19 strains tested. The possible effects of these insertions on the virulence of the strains are discussed.
authors.affiliation: Université de Tours, UMR1282 Infectiologie et Santé Publique, Équipe Bactéries et Risque Materno-Foetal, Faculté de Médecine, boulevard Tonnellé, Tours, France. maud.flechard@voila.fr
authors.forename: Maud
authors.initials: M
authors.lastname: Fléchard
authors.forename: Philippe
authors.initials: P
authors.lastname: Gilot
authors.forename: Geneviève
authors.initials: G
authors.lastname: Héry-Arnaud
authors.forename: Laurent
authors.initials: L
authors.lastname: Mereghetti
authors.forename: Agnès
authors.initials: A
authors.lastname: Rosenau
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011247:Pregnancy; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D014774:Virulence
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial