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Title: Upregulation of STM3175 Decreases Bacterial Motility and Swine Colonization in a qseC (preB) Mutant of Salmonella enterica serovar Typhimurium

Author
item Bearson, Bradley - Brad
item Bearson, Shawn
item LEE, IN SOO - Hannam University

Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/19/2009
Publication Date: 10/5/2009
Citation: Bearson, B.L., Bearson, S.M., Lee, I. 2009. Upregulation of STM3175 Decreases Bacterial Motility and Swine Colonization in a qseC (preB) Mutant of Salmonella enterica serovar Typhimurium. ASM Conference on Salmonella: Biology, Pathogenesis & Prevention, October 5-9, 2009, Aix-en-Provence, France. p. 41.

Interpretive Summary:

Technical Abstract: Inactivation of the QseC (PreB) sensor kinase decreases bacterial motility and pathogen colonization of the swine gastrointestinal tract for Salmonella enterica serovar Typhimurium (S. Typhimurium). In contrast, both the qseB [encoding the QseB (PreA) response regulator] and qseBC mutants had motility phenotypes similar to wild-type S. Typhimurium. The qseBC mutant was also able to colonize the swine gastrointestinal tract similar to wild-type S. Typhimurium. Thus, our data indicates that the presence of the QseB (PreA) response regulator in a qseC mutant decreases bacterial motility and swine colonization, and inactivation of the qseBC operon restores these bacterial phenotypes similar to wild-type S. Typhimurium. These results suggest that QseB is a negative regulator of genes involved in bacterial motility and swine colonization. Transcriptional analysis using DNA microarrays of a S. Typhimurium strain overexpressing qseB (preA) in a Delta qseBC (Delta preAB) background indicated that STM3175 was up-regulated (Merighi et al., BMC Microbiol. 2009, 9:42). The STM3175 protein is a putative regulatory protein in the AraC family. To determine whether STM3175 is responsible for decreased motility of a qseC mutant of S. Typhimurium, a qseC STM3175 mutant was constructed. Bacterial motility was increased for the qseC STM3175 mutant compared to the qseC mutant and indicates that STM3175 is a negative regulator of motility in S. Typhimurium. In addition, transcriptional fusions to specific genes in the QseBC (PreAB) regulon that are up-regulated in a qseC (preB) mutant were down-regulated in a qseC STM3175 mutant. Our data indicates that increased expression of STM3175 due to the qseC (preB) mutation decreases bacterial motility and suggests that upregulation of genes in the QseBC (PreAB) regulon are responsible for decreased colonization of the swine gastrointestinal tract by the qseC (preB) mutant.