“Dissemination of the Tn402 transposon family among bacterial genomes.”

QUIROGA C, SCALZO PM, QUIROGA MP Y CENTRÓN D.

Rosario

Congreso; V Congreso de Microbiología General. SAMIGE; 2008

SAMIGE

Background TniC-like transposons  often carry a class 1 integron and have complete transposition genes and are functional. They are closely related to the transposon carrying the commonly found class 1 integron which is a derivative of the tniC-like transposon that has suffered a large deletion. This has removed genes tniC, orf6 and tniB, necessary for mobility. TniC-like transposons can carry numerous resistance genes and have recently been found to carry powerful metallo-b-lactamase genes and are emerging worldwide. However, these elements are poorly studied and until very recently only a couple of copies of these transposons were in genome data-bases. Here we present a recent in-silico analysis of new additions of these elements to the genetic data-bases. Methods A section of the sequence of the tniC transposon Tn5090 including the entire transposition locus from tniC to the inverted repeat IRt was used to interrogate the genetic databases at EBI Hinxton UK using the FASTA program. Sequences were aligned by megalign and phylogenetic trees and distance measures were constructed. Results The searches produced a number of high scoring sequences including about 15 with high identity throughout (>85%). Of these some were duplicates as they included several copies from the same genome sequence. Representatives of each sequence were aligned and included examples from Delftia acidovorans plasmid pU01, Pseudomonas sp ED23-33, plasmid p07172 from Citrobacter Youngae, Ralstonia metalluridans CH34, Enterobacter cloacae 0-4740, incP-1 alpha plasmid pBS228 and P. stuttzeri. Phylogenetic analysis indicates three main groups of this transposon. Of interest was the observation that some of these transposons did not contain a class 1 integron (Ralstonia metalluridans CH34 and P. stutzeri). Conclusions Several new additions to the data-bases from genome sequencing projects indicate that TniC-like transposons are well disseminated. In addition examples of this transposon that lack the class 1 integron likely correspond to the ancestors of the commonly found integron structures.