From intestine to beyond:entry factors display distinct transcription pattern upon infection in murine models.

Abstract

The infectious process of bacteria of the genusrequires the finely regulated use of various virulence factors. Among them, the type 3 secretion system-1 (T3SS-1) and the Rck and PagN invasins are involved in the internalization of the pathogen within eukaryotic cells, but their precise role in the host and in the pathogenic process is still poorly understood. In this study, we aimed to determine the kinetics of expression of these entry factors in a typhoid fever-like and a gastroenteritis model in mice byimaging using bioluminescentTyphimurium reporter strains carrying chromosomal transcriptional fusions. Onlyand T3SS-1 transcription has been clearly identified. Independently of the pathological model, the caecum was identified as the main transcription site of bothand the T3SS-1-encoding gene both at early and late stages of the infection. An intense transcription ofwas also observed in deep organs in the typhoid fever-like model, while that of T3SS-1 remained quite sporadic in these organs, and mainly focused on the intestine all along the infection. This work will help to understand the respective role of these entry factors at the cellular level in the pathogenesis of.