Variabilidad y evolución del gen cassette aadA1

GALÁN AV; QUIROGA MP; CENTRON D

Córdoba

Congreso; XI Congreso Argentino de Microbiología General SAMIGE.; 2015

SAMIGE

Genecassettes (GC)are mobile elements associated to horizontal gene transfer inserted in integrons. Theaim of this study was to analyze the variability and evolution of both full GCand its individual components, ORF and attC of the aadA GC. A search was conducted on INTEGRALLdatabase for different alleles of the aadA GC and a further study was made in GenBankdatabase with aadA1 attC GC reference sequence to identifyassociated GC, and the GC position in different Integrons. We found 37 alleles of aadA fromIntegralldatabase. As expected, the alignment of GC sequences occurred mainly by thenucleotide bases located at the beginning and the end of the sequence ofdifferent attCssites, which are important for recombination. Regarding to 2L and 2R regions,which are associated to the formation of an extra-helical base, 30 alleles havethe consensus sequences. The maximum likelihood algorithm tree based on the attCsites evidenced that the predominant attC site was associated to 15 aadAalleles. Trees of full cassettes and ORFs were identical and only havedifferences with the attC sites tree. In class 1 integrons aadA1 wasmainly located in the second position within the variable region of the integron anddownstream of dfrA1 GC, but also frequently as the onlycassette in the variable region. In class 2 integrons aadA1 was found mostly in third place, alsoassociated to dfrA1 GC and less frequently downstream of sat2orcatB8 GCs