title: NAC transcription factor ORE1 and senescence-induced BIFUNCTIONAL NUCLEASE1 (BFN1) constitute a regulatory cascade in Arabidopsis.
abstract: Senescence is a highly regulated process that involves the action of a large number of transcription factors. The NAC transcription factor ORE1 (ANAC092) has recently been shown to play a critical role in positively controlling senescence in Arabidopsis thaliana; however, no direct target gene through which it exerts its molecular function has been identified previously. Here, we report that BIFUNCTIONAL NUCLEASE1 (BFN1), a well-known senescence-enhanced gene, is directly regulated by ORE1. We detected elevated expression of BFN1 already 2 h after induction of ORE1 in estradiol-inducible ORE1 overexpression lines and 6 h after transfection of Arabidopsis mesophyll cell protoplasts with a 35S:ORE1 construct. ORE1 and BFN1 expression patterns largely overlap, as shown by promoter-reporter gene (GUS) fusions, while BFN1 expression in senescent leaves and the abscission zones of maturing flower organs was virtually absent in ore1 mutant background. In vitro binding site assays revealed a bipartite ORE1 binding site, similar to that of ORS1, a paralog of ORE1. A bipartite ORE1 binding site was identified in the BFN1 promoter; mutating the cis-element within the context of the full-length BFN1 promoter drastically reduced ORE1-mediated transactivation capacity in transiently transfected Arabidopsis mesophyll cell protoplasts. Furthermore, chromatin immunoprecipitation (ChIP) demonstrates in vivo binding of ORE1 to the BFN1 promoter. We also demonstrate binding of ORE1 in vivo to the promoters of two other senescence-associated genes, namely SAG29/SWEET15 and SINA1, supporting the central role of ORE1 during senescence.
authors: University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Straβe 24-25, 14476 Potsdam-Golm, Germany.
authors: Lilian P
authors: LP
authors: Matallana-Ramirez
authors: Mamoona
authors: M
authors: Rauf
authors: Sarit
authors: S
authors: Farage-Barhom
authors: Hakan
authors: H
authors: Dortay
authors: Gang-Ping
authors: GP
authors: Xue
authors: Wolfgang
authors: W
authors: Dröge-Laser
authors: Amnon
authors: A
authors: Lers
authors: Salma
authors: S
authors: Balazadeh
authors: Bernd
authors: B
authors: Mueller-Roeber
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003851:Deoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D018506:Gene Expression Regulation, Plant; D058503:Mesophyll Cells / Q000166:cytology / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000235:genetics; D011523:Protoplasts / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C513622:BFN1 protein, Arabidopsis; C538850:ORE1 protein, Arabidopsis; D014157:Transcription Factors; D003851:Deoxyribonucleases
keywords: Arabidopsis thaliana; BFN1; ORE1; promoter; senescence; transcription factor