title: DNA-mediated redox signaling for transcriptional activation of SoxR.
abstract: In enteric bacteria, the cellular response to oxidative stress is activated by oxidation of the iron-sulfur clusters in SoxR, which then induces transcription of soxS, turning on a battery of defense genes. Here we demonstrate both in vitro and in cells that activation of SoxR can occur in a DNA-mediated reaction with guanine radicals, an early genomic signal of oxidative stress, serving as the oxidant. SoxR in its reduced form is found to inhibit guanine damage by repairing guanine radicals. Moreover, cells treated with a DNA-binding photooxidant, which generates guanine radicals, promotes the expression of soxS. In vitro, this photooxidant, tethered to DNA 80 bp from the soxS promoter, induces transcription by activating SoxR upon irradiation. Thus, transcription can be activated from a distance through DNA-mediated charge transport. This chemistry offers a general strategy for DNA-mediated signaling of oxidative stress.
authors: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors: Paul E
authors: PE
authors: Lee
authors: Bruce
authors: B
authors: Demple
authors: Jacqueline K
authors: JK
authors: Barton
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D006147:Guanine / Q000378:metabolism; D008027:Light; D008954:Models, Biological; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D015398:Signal Transduction / Q000187:drug effects / Q000528:radiation effects; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D016877:Oxidants; D014157:Transcription Factors; C070724:SoxR protein, Bacteria; D006147:Guanine