Targets of the WRKY53 transcription factor and its role during leaf senescence in Arabidopsis.
Arabidopsis WRKY proteins comprise a family of plant specific zinc-finger-type transcription factors involved in the regulation of gene expression during pathogen defense, wounding, trichome development, and senescence. To understand the regulatory role of the senescence-related WRKY53 factor, we identified target genes of this transcription factor by a pull down assay using genomic DNA and recombinant WRKY53 protein. We isolated a number of candidate target genes including other transcription factors, also of the WRKY family, stress- and defence related genes, and senescence-associated genes (SAGs). WRKY53 protein could bind to these different promoters in vitro and in vivo and it could act either as transcriptional activator or transcriptional repressor depending on the sequences surrounding the W-boxes. Overexpression, RNAi and knock-out lines showed accelerated and delayed senescence phenotypes, respectively, and exhibited altered expression levels of the target genes. WRKY53 can be induced by H2O2 and can regulate its own expression in a negative feed back loop. Our results suggest that WRKY53 acts in a complex transcription factor signalling network regulating senescence specific gene expression and that hydrogen peroxide might be involved in signal transduction.
Miao
Y
Y
ZMBP (Centre of Molecular Biology of Plants), Department of General Genetics, University Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Laun
T
T
Zimmermann
P
P
Zentgraf
U
U
D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015152:Blotting, Northern; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D018515:Plant Leaves / Q000235:genetics* / Q000502:physiology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D015003:Yeasts / Q000235:genetics
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D018749:RNA, Plant; D011994:Recombinant Proteins; D014157:Transcription Factors; C496136:WRKY53 protein, Arabidopsis; D006861:Hydrogen Peroxide; D005966:Glucuronidase