GodS, a transcriptional regulator that responds to gold.

MARÍA E. PÉREZ AUDERO; PABLO E. BOTTA; MARTÍN ESPARIZ; LUCAS B. PONTEL; SUSANA K. CHECA; FERNANDO C. SONCINI

Iguazú, Misiones, Argentina.

Congreso; Argentine Society for Biochemistry and Molecular Biology XL Annual Meeting. Protein Phosphorylation and Bioregulation Symposium.; 2004

Sociedad Argentina de Bioquímica y Biología Molecular.

The MerR family of proteins is a group of transcriptional regulators that respond specifically to a variety environmental stimuli, such as oxidative stress, heavy metals or antibiotics. We have identified a gene (hmrR) coding for a MerR-like protein located in a Salmonella thypimurium specific region. This gene form an operon with hmrT which encodes a putative P-type ATPase. Dowstream of hmrR there is a gen (hmrB) with significant similarity to copper chaperon proteins.The goal of this work was to characterize the hmr regulon and identify the signal that it recognize. b- galactosidase activity and western blot assays demonstrate that HmrR regulates not only the expression of hmrT and hmrB but also its own synthesis. Transcriptional activity determination in the presence of mono, di and trivalents metal ions demonstrates that gold salts is the only inducer of this system. Strains lacking hmrR have not gold induced activation of genes. The responsive to gold was fully restored upon expression of HmrR from a plasmid. By mobility shift assay we demonstrate that HmrR protein bound specifically to the promotor regions of hmrTR and hmrB even when gold was absent. In this study, we showed that HmrR, identified in an previous work, responds specifically to gold. This regulator modulates its own syntesis and hmrT and hmrB expression.