The expression of iron storage gene of E. coli under a range of environmental condition

Background: Organisms must balance their iron requirement to achieve iron homeostasis. This is achieved through several mechanisms, including sequestration of excess cellular iron by iron-storage proteins, Escherichia coli contain three iron-storage proteins act as an iron source under iron restriction. Aim: to investigate the respective functions of Dps and to determine whether this protein is mutually interchangeable, and to assess the change in the expression of dps gene in different conditions. Methods: generating a triple mutant of the corresponding iron-storage genes by P1transduction, mutant complemented with plasmid expressing dps. qRT-PCR was used, for the iron storage gene and housekeeping gene, Western blot was used for protein detection. Results: mutant complementation shows that Dps can enhance the growth under iron-restricted/ and redox stress, due to the strong induction of dps by rhamnose. Western blot analysis clearly shows the positive effect of iron aerobically on the production of Dps protein. Conclusion: Dps has capacity to provide resistance against both iron and peroxide-induced stress. The results of western blot correlate well with RNA of iron storage gene expression. it is notable that the Dps band (in stationary phase) is detectable in low intensity in iron insufficiency aerobically; but the intensity is increased in the presence of iron; indicating the translational up-regulation of this protein. Its production is also increased in anaerobic condition (+/- iron) reflecting the perceived physiological role of Dps in providing peroxide/Fe toxicity resistance and prevent DNA damage.