Characterization of temperature ‐dependent hemin uptake receptors HupA and HvtA in Vibrio vulnificus

This study expands our understanding of the contribution of thehvtA locus inVibrio vulnificus to virulence by uncovering an important correlation between gene expression and environmental temperature. This temperature ‐mediated regulation is coupled with responsiveness to iron depletion. AbstractThe Gram ‐negative pathogenVibrio vulnificus produces several iron ‐sequestration systems including a hemin uptake system in response to iron limitation as a means to acquire this essential element. Strains of this organism are capable of causing serious septicemia in humans and eels, where hemin is abundant and an advantageous source of iron.Vibrio vulnificus hemin uptake systems consist of HupA, a well studied outer membrane protein, and a recently identified HvtA protein receptor. In this study, we confirmed that the expression of thehvtA gene is iron ‐regulated in a fur‐dependent manner. When analyzed for virulence in a hemin‐overloaded murine model system, thehupA gene was more important for establishing infection than thehvtA gene. Transcriptional profiling of these genes using strains of two different biotypes, biotype 1 (human pathogen) and biotype 2 (eel pathogen), showed that the expression of the two receptors was also regulated in response to temperature. The expression ofhupA was highly induced in elevated temperatures in the human pathogenic strain when tested in iron ‐depleted conditions. Conversely,hvtA expression was induced significantly in the eel path...
Source: MicrobiologyOpen - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research