REF4 and RFR1, subunits of the transcriptional coregulatory complex mediator, are required for Phenylpropanoid homeostasis in Arabidopsis

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DOIResolve DOI: http://doi.org/10.1074/jbc.M111.312298
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleJournal of Biological Chemistry
ISSN0021-9258
1083-351X
Volume287
Issue8
Pages54345445; # of pages: 12
SubjectAnthocyanin accumulation; Arabidopsis; Arabidopsis thaliana mutant; Binding partners; Biosynthetic gene; Cis-acting DNA; Core promoters; Eukaryotic gene regulation; Human health; Human needs; Mediator complex; Metabolic pathways; Mutant proteins; Paralogs; Phenylpropanoid pathways; Phenylpropanoids; Rational Manipulation; RNA polymerase II; Wild types
AbstractThe plant phenylpropanoid pathway produces an array of metabolites that impact human health and the utility of feed and fiber crops. We previously characterized several Arabidopsis thaliana mutants with dominant mutations in REDUCED EPIDERMAL FLUORESCENCE 4 (REF4) that cause dwarfing and decreased accumulation of phenylpropanoids. In contrast, ref4 null plants are of normal stature and have no apparent defect in phenylpropanoid biosynthesis. Here we show that disruption of both REF4 and its paralog, REF4-RELATED 1 (RFR1), results in enhanced expression of multiple phenylpropanoid biosynthetic genes, as well as increased accumulation of numerous downstream products. We also show that the dominant ref4-3 mutant protein interferes with the ability of the PAP1/MYB75 transcription factor to induce the expression of PAL1 and drive anthocyanin accumulation. Consistent with our experimental results, both REF4 and RFR1 have been shown to physically associate with the conserved transcriptional coregulatory complex, Mediator, which transduces information from cis-acting DNA elements to RNA polymerase II at the core promoter. Taken together, our data provide critical genetic support for a functional role of REF4 and RFR1 in the Mediator complex, and for Mediator in the maintenance of phenylpropanoid homeostasis. Finally, we show that wild-type RFR1 substantially mitigates the phenotype of the dominant ref4-3 mutant, suggesting that REF4 and RFR1 may compete with one another for common binding partners or for occupancy in Mediator. Determining the functions of diverse Mediator subunits is essential to understand eukaryotic gene regulation, and to facilitate rational manipulation of plant metabolic pathways to better suit human needs.
Publication date
PublisherAmerican Society for Biochemistry and Molecular Biology
LanguageEnglish
AffiliationNational Research Council Canada; Aquatic and Crop Resource Development
Peer reviewedYes
NRC number55452
NPARC number21268527
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Record identifier726d0484-dc0b-4e76-b3ae-30acbb0ab9ec
Record created2013-09-09
Record modified2016-05-09
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