The rpoN gene of Brucella abortus is important for the bacterial persistence in mice

IANNINO, F.; CIOCCHINI, A.; VIDAL-RUSSELL, R.; UGALDE, R. A.; IÑÓN DE IANNINO, N.

Bariloche, Rio Negro, Argentina.

Congreso; Sociedad Argentina de Investigación en Bioquímica y Biología Molecular, XXXIX Reunión anual; 2003

rpoN encodes the alternative sigma factor sigma 54, which is required for transcription of a wide range of genes involved in diverse physiological functions such as nitrogen metabolism, dicarboxylic acid transport and xylene degradation. Sigma 54 is also involved in the regulation of virulence-related factors in both plant and animal pathogens, including synthesis of flagellar and pilus components. A gene with high homology to Agrobacterium tumefaciens sigma 54 was identified in Brucella abortus. Given the facts that RpoN activates the expression of a wild variety of environmentally regulated genes and is required for virulence in a variety of pathogens we hypothesized that RpoN would play a central role in B. abortus virulence. In this study we describe the results of experiments that involved the construction of a B. abortus rpoN mutant in order to study the role of sigma 54 in B. abortus pathogenesis in HeLa cells, murine macrophage J774 cell line and in Balb/c mice. We concluded that B. abortus rpoN is not essential for infection and multiplication in nonphagocytic or phagocitic cells, however rpoN may be important for the bacterial persistence in Balb/c mice.