1887

Abstract

Hypervirulent atypical El Tor biotype O1 isolates harbour mutations in the DNA-binding domain of the nucleoid-associated protein H-NS and the receiver domain of the response regulator VieA. Here, we provide two examples in which inactivation of H-NS in El Tor biotype vibrios unmasks hidden regulatory connections. First, deletion of the helix-turn-helix domain of VieA in an mutant background diminished biofilm formation and exopolysaccharide gene expression, a function that phenotypically opposes its phosphodiesterase activity. Second, deletion of in an mutant diminished the expression of σ, a virulence determinant that mediates the envelope stress response. mutants were highly sensitive to envelope stressors compared to wild-type. However, deletion of in the mutant restored or exceeded wild-type resistance. These findings suggest an evolutionary path for the emergence of hypervirulent strains starting from nucleotide sequence diversification affecting the interaction of H-NS with DNA.

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2018-07-01
2019-12-06
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