STUDY OF THE SBMA GEN REGULATION IN ESCHERICHIA COLI

CORBALáN, NATALIA; DELGADO, MóNICA A.; VINCENT, PAULA A.

Mar del Plata

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología molecular.; 2007

Sociedad Argentina de Investigaciones en Bioquímica y Biología molecular.

E. coli SbmA transports MccB17, MccJ25, and bleomycin into the cell cytoplasm. Homologs of the sbmA gene are found in a variety of bacteria suggesting an important physiological role might exist for these genes however it remain unknown. In this work we described the study of the sbmA regulation and the sbmA mutant sensitivity to different agents. Using the GPS bioinformatical program, we demonstrated that the SlyA regulator has a putative binding site on the sbmA promotor region. To confirm these results we performed â-galactosidases assays, and found that sbmA transcription is negatively regulated by SlyA. We also probed the expression in conditions of MccJ25 accumulation studying sbmA::lacZ expression in a tolC mutant. Interesting, in the absent of the antibiotic we still observed high level of â-galactosidase activity, indicating a positive regulation by tolC mutation. We also observed that sbmA is expressed mainly during the stationary phase and this expression levels was increased when the mutant growth in minimal medium containing low Mg2+ concentration. We only found a partial resistance to polymyxin B in sbmA mutant when the sensitivity of this strain was probed to several agents. Ours preliminary results led us to propose a hypotetical regulation of sbmA by SlyA and PhoP/PhoQ in E. coli.