Salmonella enterica serotype Typhimurium (S. typhimurium) definitive phage type (DT) 104 has become a widespread cause of human and animal infections worldwide. The severity of the clinical illness in Salmonella Typhimurium DT104 outbreaks suggests that this strain possesses enhanced virulence. ArtA and ArtB-encoded by the prophage in Salmonella Typhimurium DT104-are homologues of components of the pertussis toxin (PTX), including its ADP-ribosyltransferase subunit. Here, we show that exposing DT104 to mitomycin C, a DNA-damaging agent, induced prophage-encoded ArtA/ArtB expression. Pertussis-sensitive G proteins were labeled in the presence of [32P]NAD and ArtA. The results of the cellular ADP-ribosylation assay and analysis of the two-dimensional electrophoresis showed that ArtA- and PTX-induced ADP-ribosylation in the Chinese hamster ovary (CHO) cells occur with the same type of G proteins. Furthermore, exposing CHO cells to the ArtA/ArtB-containing culture supernatant of DT104 resulted in a clustered growth pattern as was observed in PTX-exposed CHO cells. Taken together, these results suggest that ArtA is an active toxin similar to PTX and may contribute to the pathogenesis of Salmonella Typhimurium DT104.
(Research Team for Environmental/Enzootic Diseases, Hokkaido Research Station, TEL +81-29-838-7708)
References:
- Saitoh, M. et al. (2005) Microbiology. 151:3089-3096.
- Uchida, I. et al. (2009) Microbiology. 155:3710-3718.
