INVESTIGADORES
QUIROGA Maria Paula
congresos y reuniones científicas
Título:
Dissemination of the Tn402 transponson family among bacterial genomes
Autor/es:
QUIROGA CECILIA; SCALZO PAULA MARINA; QUIROGA MARÍA PAULA; CENTRÓN DANIELA
Lugar:
Rosario
Reunión:
Congreso; V Congreso de Microbiología General; 2008
Institución organizadora:
Sociedad Argentina de Microbiología General (SAMIGE).
Resumen:
The Tn402 transposon has been first described in the IncP1 plasmid R751 from Enterobacter aerogenes. Tn402 is the single active transposon that carries a class 1 integron; however, only the Tn402 derivatives were found spread among the clinical isolates. This transposon contains the complete transposition gene module consisting of four genes, tniA, B, Q and R. The Tn402 transposes to a relatively specific target, the res site, which is recognized by the resolvase similarly to the Tn5053 transposon . It has been previously reported that the Tn402 transposon was an ancient vehicle for the spread of resistance genes (Stokes 2006). The aim of this work is to understand the role and evolution of the Tn402 in the bacterial kingdom as well as to evaluate its presence in a low antropic environmental niche. First, we did a comprehensive screening of the tni module using a computer based analysis of complete (n = 736) and partial (n = 1181) bacterial genomes released in the public database GenBank using the BLASTP algorithm. The TniR protein sequence of the Tn402 transposon from Enterobacter aerogenes (AN NC_001735) was used as query resulting in c.a 30 genomes with a sequence identity higher to 80%; however only 13 of them were considered in our study since they contained the complete tni module (Table 1). Among those genomes, only a few have been previously reported an/or studied. Our results showed that the incidence of the tni module dissemination is quite limited if we consider that only 1.3% (n=10) of the complete bacterial genomes harboured it. Most tni modules found in bacterial plasmids belonged to the IncP-1 incompatibility group except for three that had the tni operon located in their respective chromosomes, Ralstonia metallidurans CH34, Pseudomonas stutzeri A1501 and Burkholderia xenovorans LB400. Altogether these results indicates that the tniR gene can be found in marine bacteria but our results indicates that the tni module from environmental isoaltes were not associated to class 1 integrons. Therefore, they are most likely found in chromosomal locations as seen by the in silico analysis. The presence of the tniR gene with no clear association to the mer operon or to the intI1 integrase gene is consistant with previous reports.