05-Physiol Plant -antiox&H2O2

05-Physiol Plant -antiox&H2O2 - PHYSIOLOGIA...

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Unformatted text preview: PHYSIOLOGIA PLANTARUM 106: 112–120. 1999 Copyright © Physiologia Plantarum 1999 Printed in Ireland — all rights reser 6 ed ISSN 0031-9317 Role of hydrogen peroxide and different classes of antioxidants in the regulation of catalase and glutathione S-transferase gene expression in maize ( Zea mays L.) Alexios N. Polidoros and John G. Scandalios* Department of Genetics , North Carolina State Uni 6 ersity , Raleigh , NC 27695- 7614 , USA *Corresponding author , e- mail : jgs@unity . ncsu . edu Received 3 February 1999 gene / compound / concentration combination examined. The re- The role of hydrogen peroxide (H 2 O 2 ) and various antioxi- dants in the regulation of expression of the three Cat and Gst 1 sponse of each gene to each antioxidant compound tested was unique, suggesting that the ability of these compounds to genes of maize ( Zea mays L.) has been investigated. Low concentrations of H 2 O 2 appeared to inhibit Cat 1 , Cat 3 , and affect expression of the maize Cat and Gst 1 genes may not be Gst 1 gene expression, while higher doses strongly induced the result of a common (antioxidant) mode of action. A these genes. Time course experiments indicated that high putative regulatory ARE motif involved in the regulation of antioxidant and oxidative stress gene responses in mammalian concentrations of H 2 O 2 induced Cat 1 , Cat 2 , and Gst 1 gene systems is present in the promoter of all three maize catalase expression to higher levels, and in less time, than lower H 2 O 2 concentrations. Induction of Cat 3 was superimposed on the genes and we tested its ability to interact with nuclear extracts circadian regulation of the gene. These results demonstrate a prepared from 10 days post-imbibition senescing scutella. direct signaling action of H 2 O 2 in the regulation of antioxi- Protein-DNA interactions in the ARE motif and the U2 snRNA homologous regions of the Cat 1 promoter were ob- dant gene responses in maize. The effects of the antioxidant compounds N-acetylcysteine, served, suggesting that ARE may play a role in the high induction of Cat 1 in a tissue which, due to senescence, is under pyrrolidine dithiocarbamate, hydroquinone, and the elec- trophile antioxidant responsive element (ARE)-inducer b- oxidative stress. naphthoflavone were quite different and specific for each a number of transcriptional factors that regulate the expres- sion of antioxidant genes, or genes whose activities are modulated by oxidation and reduction, are known. In Es- cherichia coli and other prokaryotes the transcription factor OxyR activates a battery of genes inducible by H 2 O 2 , while the transcription factors SoxR / SoxS mediate responses to O 2- . Similarly, in the yeast Saccharomyces cere 6 isiae , a lower eukaryote, there are two distinct adaptive stress re- sponses, one towards H 2 O 2 and one towards O 2- (Jamieson and Storz 1997)....
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This note was uploaded on 09/13/2010 for the course DGPB 024e taught by Professor Alexiospolidoros during the Spring '10 term at Aristotle University of Thessaloniki.

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05-Physiol Plant -antiox&H2O2 - PHYSIOLOGIA...

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