Authors: W Rungrassamee X Liu P J Pomposiello
Publish Date: 2008/03/27
Volume: 190, Issue: 1, Pages: 41-49
Abstract
Global transcription studies have identified a large number of redoxresponsive genes although the biological relevance of this regulation has not been experimentally tested In particular several genes coding for enzymes involved in glucose metabolism have been identified as redoxresponsive in Escherichia coli However only zwf which codes for glucose6phosphate dehydrogenase has been shown experimentally to affect the cellular resistance to oxidative stress We addressed the question of whether ptsG coding for the membrane component of the glucosespecific transporter system and pgi coding for phosphoglucose isomerase two additional genes identified in wholegenome functional screens are indeed relevant in antioxidant defense PTS assays showed that glucose transport was induced under oxidative stress elicited by the superoxideproducing agent paraquat PQ This induction of glucose transport under oxidative stress was dependent on the soxRS genes coding for a sensor transcriptional activator system and ptsG The binding of purified SoxS to the ptsG promoter region was shown by gel mobilityshift assay and the activation of the ptsG promoter P1 was demonstrated by primer extension assays Finally a ptsG mutant strain was hypersensitive to PQ when grown in rich medium plus glucose but not in rich medium without glucose The pgi gene showed the same pattern of regulation by oxidative stress under the control of the SoxRS system and a strain carrying a pgi deletion was hypersensitive to PQThe authors want to thank Carla Risso for her many useful comments on the manuscript and to K Jahreis and G Sprenger for generous gifts of strains This work was supported by a UMassAmherst Faculty Research Grant to PJP and a Royal Thai Government Fellowship to ER
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