SagA, A NOVEL SECRETION ACTIVATOR FACTOR OF Brucella abortus

DEL GIUDICE MG; UGALDE JE; CZIBENER C

Puerto Madryn, Chubut, Argentina

Congreso; SAIB 46th Annual Meeting.; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Brucellosis, a world-wide distributed zoonosis that affects a broad range of mammals and causes important economical loses, is caused by bacteria of the genus Brucella. The majority of the known species of this genus are pathogenic for humans and their pathogenicity is associated with the capacity to survive and replicate within host cells. With the purpose of identifying novel virulence genes we compared the genome of Brucella abortus with the rest of the sequenced species searching for differences between this and the less pathogenic ones. As a result of this search we identified a region of 15 Kb that is absent in B. ovis, the only species non-pathogenic for human. The structural characteristics of this chromosomal region, which we have designated Bab_0983, strongly suggest that it could have been horizontally acquired and, thus, is a strong candidate to harbor putative virulence genes. Analysis of this region indicates that it contains 20 ORFs, the majority of them with unknown function. One of these ORFs, Bab_1002 (designated sagA), codes for a protein with homology to peptidoglycan hydrolases and has been implicated in other microorganisms in the secretion of proteins through the outer membrane. Our results suggest that this gene is probably implicated in the secretion of proteins to the surface of the bacteria that mediate attachment and internalization into host cell.