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First published online February 23, 2007; 10.1104/pp.106.091819 Plant Physiology 143:1519-1533 (2007) © 2007 American Society of Plant Biologists OPEN ACCESS ARTICLE
Characterization of the Regulatory and Expression Context of an Alternative Oxidase Gene Provides Insights into Cyanide-Insensitive Respiration during Growth and Development1,[C],[W],[OA]Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia
Alternative oxidase (AOX) is encoded in small multigene families in plants. Functional analysis of the Arabidopsis (Arabidopsis thaliana) alternative oxidase 1c (AtAOX1c) promoter, an AOX gene not induced by oxidative stress, indicated that regulation of expression was complex, with the upstream promoter region containing positive and negative response regions. Comparison to the promoter region of soybean (Glycine max) alternative oxidase 2b (GmAOX2b), another AOX gene not induced by oxidative stress, revealed that they contained seven sequence elements in common. All elements were active in the promoter region of AtAOX1c in suspension cells and in leaf tissue from Columbia and mutant plants, where a mitochondrial protein import receptor was inactivated. Analysis of coexpressed and putatively coregulated genes, the latter defined as containing five or more sequence elements functional in AtAOX1c, indicated that AtAOX1c was coregulated with components involved with cell division and growth. Consistent with this analysis, we demonstrated that site II elements, previously shown to regulate the proliferating cell nuclear antigen, are present in the upstream promoter region of AtAOX1c and were strong negative regulators of AtAOX1c expression. It was demonstrated that NDB4, a gene encoding an external NAD(P)H dehydrogenase, displayed strong coexpression with AtAOX1c. Overall, these results indicate that AtAOX1c is regulated by growth and developmental signals.
1 This work was supported by the Australian Research Council Centre of Excellence in Plant Energy Biology. 2 These authors contributed equally to the paper. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: James Whelan (seamus{at}cyllene.uwa.edu.au). [C] Some figures in this article are displayed in color online but in blank and white in the print edition. [W] The online version of this article contains Web-only data. [OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.106.091819 * Corresponding author; e-mail seamus{at}cyllene.uwa.edu.au; fax 61864884401. Received October 23, 2006; accepted February 2, 2007; published February 23, 2007. This article has been cited by other articles:
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