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Correction published on 1 September 2016, see Plants 2016, 5(3), 35.
Article

Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1

ZMBP, General Genetics, University of Tuebingen, Auf der Morgenstelle 32, Tuebingen 72076, Germany
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Academic Editor: Salma Balazadeh
Received: 8 July 2015 / Revised: 12 August 2015 / Accepted: 8 September 2015 / Published: 16 September 2015
(This article belongs to the Special Issue Plant Senescence)
Massive changes in the transcriptome of Arabidopsis thaliana during onset and progression of leaf senescence imply a central role for transcription factors. While many transcription factors are themselves up- or down-regulated during senescence, the bZIP transcription factor G-box-binding factor 1 (GBF1/bZIP41) is constitutively expressed in Arabidopsis leaf tissue but at the same time triggers the onset of leaf senescence, suggesting posttranscriptional mechanisms for senescence-specific GBF1 activation. Here we show that GBF1 is phosphorylated by the threonine/serine CASEIN KINASE II (CKII) in vitro and that CKII phosphorylation had a negative effect on GBF1 DNA-binding to G-boxes of two direct target genes, CATALASE2 and RBSCS1a. Phosphorylation mimicry at three serine positions in the basic region of GBF1 also had a negative effect on DNA-binding. Kinase assays revealed that CKII phosphorylates at least one serine in the basic domain but has additional phosphorylation sites outside this domain. Two different ckII α subunit1 and one α subunit2 T-DNA insertion lines showed no visible senescence phenotype, but in all lines the expression of the senescence marker gene SAG12 was remarkably diminished. A model is presented suggesting that senescence-specific GBF1 activation might be achieved by lowering the phosphorylation of GBF1 by CKII. View Full-Text
Keywords: senescence regulation; GBF1; CASEIN KINASE II; phosphorylation; phosphorylation mimicry senescence regulation; GBF1; CASEIN KINASE II; phosphorylation; phosphorylation mimicry
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MDPI and ACS Style

Smykowski, A.; Fischer, S.M.; Zentgraf, U. Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1. Plants 2015, 4, 691-709. https://0-doi-org.brum.beds.ac.uk/10.3390/plants4030691

AMA Style

Smykowski A, Fischer SM, Zentgraf U. Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1. Plants. 2015; 4(3):691-709. https://0-doi-org.brum.beds.ac.uk/10.3390/plants4030691

Chicago/Turabian Style

Smykowski, Anja, Stefan M. Fischer, and Ulrike Zentgraf. 2015. "Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1" Plants 4, no. 3: 691-709. https://0-doi-org.brum.beds.ac.uk/10.3390/plants4030691

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