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Characterization of two H-NS-family proteins in the opportunistic pathogen, Chromobacterium violaceum.

ABSTRACT: Histone-like nucleoid structuring (H-NS) proteins silence horizontally-acquired genes, facilitating their the acquisition and integration of important traits such as virulence and antibiotic resistance in bacterial pathogens. In this work, we describe the H-NS proteins in the environmental opportunistic pathogen Chromobacterium violaceum. We show that C. violaceum encodes two H-NS proteins, Chn1 and Chn2. Transcriptomic analyses revealed that Chn1 is the predominant H-NS-family protein in C. violaceum, repressing many genes, while Chn2 is largely compensatory, exhibiting a phenotype only in a double mutant, chn1 chn2 strain. This is reinforced by in silico analyses showing that chn1 is conserved throughout Chromobacterium, while chn2 is species-dependent, and likely horizontally-acquired. The expression of 213 genes, including the Chromobacterium pathogenic island 2 (Cpi-2), was de-repressed in the chn1 chn2 mutant. Phenotypic analyses revealed altered virulence, violacein production, motility and acid and osmolarity tolerance in chn1 and chn1 chn2 mutant strains, demonstrating the prominent role of these H-NS-family proteins as global regulators of virulence-associated traits in C. violaceum.

ORGANISM(S): Chromobacterium violaceum

PROVIDER: GSE304743 | GEO | 2026/08/31

REPOSITORIES: GEO

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