Transcriptomic analysis of Vibrio vulnificus in response to iron concentration and Fur protein

V. vulnificus is a marine bacteria that causes diseases in both mammals and fish. In both hosts, the iron concentration represents a key factor that greatly influences the virulence of this bacterium. To further define the gene repertoire that is regulated by iron concentration and Fur protein (the main transcriptional regulator in response to iron concentration) in V. vulnificus, we obtained a mutant in Fur and used DNA microarray technology to monitor the expression of the entire gene repertoire in response to iron. Global transcriptomic response was reconstructed by comparing the transcriptional profiles of the wild-type (R99) and Fur mutant strains in poor and rich iron conditions. To identify the genes that were under control of Fur, we compared the transcriptomic profile of the wild-type strain with the profile of a mutant strain in Fur protein; in contrast, to identify the genes that were under control of iron, we compared the transcriptomic profile of the wild-type strain grown in iron-rich conditions with the profile of the wild-type strain grown in iron-restricted conditions. For each one of the four samples, three replicates were performed, and RNA was sampled in the mid-log phase of growth (wild-type, 6h; Fur mutant, 6h; wild-type+iron, 5h; wild-type-iron,9h).