ARS | Publication request: Functional Characterization of the Putative Crp/fnr Family of Transcriptional Regulators of a Listeria Monocytogenes Serotype 4b Strain

Submitted to: Meeting Abstract
Publication Acceptance Date: January 27, 2004
Publication Date: August 8, 2004
Citation: Uhlich, G.A., Wonderling, L., Faith, N., Neudeck, B., Loeb, J., Czuprynski, C., Luchansky, J.B. 2004. Functional Characterization Of The Putative Crp/fnr Family Of Transcriptional Regulators Of A Listeria Monocytogenes Serotype 4b Strain. Meeting Abstract. P174.

Technical Abstract: A whole-genome sequence analysis of Listeria monocytogenes strain F2365 revealed 15 potential members of the Crp/Fnr family of transcriptional regulatory proteins. Each gene and the flanking regions were cloned, subjected to in vitro transpositional mutagenesis, and recombined into strain F2365. Mutant strains, produced for 14 of the family members, were compared to strain F2365 using rapid phenotypic screens to identify functional differences. Differences in carbon, nitrogen, sulfur, and/or phosphorus metabolism were identified for 13 of the mutant strains compared to strain F2365. Mutant strains KO2, KO3, and KO5 showed reductions in swarming motility compared to strain F2365 and each strain was trans-complemented to the parent phenotype by its wild-type gene. Mutant strain KO15 (prfA) showed an increase in motility, which was trans-complemented to the wild-type levels by prfA. Mutant strains KO2 and KO5 also showed reduced oxidative stress tolerance compared to strain F2365. In virulence-related screens, 13 of the mutants showed reduced expression from a plcA promoter fusion. Following an intra-gastric mouse challenge, strains KO2, KO9, KO10, and KO15 showed variations in splenic and hepatic listerial counts when compared to strain F2365. In Caco-2 cell invasion assays, strains KO2 and KO15, but not strains KO9 and KO10, showed variations in invasiveness compared to strain F2365, which correlated with their changes in mouse virulence. While several members of the Crp/Fnr family of L. monocytogenes strain F2365 affect various phenotypes studied, orf 00085 (KO2) had the most diverse affects and may represent a major regulatory gene.