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Application of an In vitro DNA Protection Assay to Visualize Stress Mediation Properties of the Dps Protein
Published on: May 31, 2013
The interplay between Mn and Fe in Deinococcus radiodurans triggers cellular protection during paraquat-induced
Sandra P Santos1,2, Yang Yang3, Margarida T G Rosa1
1ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
Abstract:
The bacterium Deinococcus radiodurans is highly resistant to several stress conditions, such as radiation. According to several reports, manganese plays a crucial role in stress protection, and a high Mn/Fe ratio is essential in this process. However, mobilization of manganese and iron, and the role of DNA-binding-proteins-under-starved-conditions during oxidative-stress remained open questions. We used synchrotron-based X-ray fluorescence imaging at nano-resolution to follow element-relocalization upon stress, and its dependency on the presence of Dps proteins, using dps knockout mutants. We show that manganese, calcium, and phosphorus are mobilized from rich-element regions that resemble electron-dense granules towards the cytosol and the cellular membrane, in a Dps-dependent way. Moreover, iron delocalizes from the septum region to the cytoplasm affecting cell division, specifically in the septum formation. These mechanisms are orchestrated by Dps1 and Dps2, which play a crucial role in metal homeostasis, and are associated with the D. radiodurans tolerance against reactive oxygen species.
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