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

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.