Contribution of yqiC in Salmonella typhimurium to the virulence in mice and temperature resistance

CARRICA M; AGUIRRE, ANDRÉS; SABIO Y GARCÍA J; ROSSETTI O; GARCÍA VÉSCOVI E; CRAVERO S

Mar del Plata, Argentina

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.

The yqiC gene of the pathogenic enterobacterium Salmonella typhimurium encodes for a 100-residue protein of unknown function that belongs to a highly conserved protein family in proteobacteria. This protein has homology with the virulence factor IivA of Brucella abortus. Similar to IivA, YqiC of Salmonella typhimurium has a predicted coiled-coil α-helix domain in the C-terminal half and it displays a trimetric structure. In order to understand the relevance of yqiC in S. typhimurium virulence, a yqiC null mutant, named St-yqiC, was constructed and the virulence of this strain was assayed. St-yqiC showed a severely attenuated phenotype in BALB/c mice inoculated intraperitoneally as well as orally. This pattern was reverted when St-yqiC was complemented in trans with the wild-type gene. On the other hand, we studied the behavior of St-yqiC in macrophage and epithelial cell lines and in different in vitro conditions, such as nutrients deprivation and the presence of H2O2, polimixine B or SDS. St-yqiC did not display a significantly altered phenotype in any of these conditions. Interestingly, we found that yqiC was involved in temperature resistance, due to the fact that St-yqiC failed to grow at 42ºC while the parental and the complemented strain grew normally at this temperature. These results contribute to understand the role of yqiC in the bacteria-host interaction.