Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1
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 (...
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| Format: | Article |
| Idioma: | English |
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MDPI AG
2015-09-01
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| Col·lecció: | Plants |
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| Accés en línia: | http://www.mdpi.com/2223-7747/4/3/691 |
| _version_ | 1830342379002920960 |
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| author | Anja Smykowski Stefan M. Fischer Ulrike Zentgraf |
| author_facet | Anja Smykowski Stefan M. Fischer Ulrike Zentgraf |
| author_sort | Anja Smykowski |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-19T21:50:49Z |
| format | Article |
| id | doaj.art-1e93a2216b674df7b2e9c245340b51a9 |
| institution | Directory Open Access Journal |
| issn | 2223-7747 |
| language | English |
| last_indexed | 2024-12-19T21:50:49Z |
| publishDate | 2015-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Plants |
| spelling | doaj.art-1e93a2216b674df7b2e9c245340b51a92022-12-21T20:04:25ZengMDPI AGPlants2223-77472015-09-014369170910.3390/plants4030691plants4030691Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1Anja Smykowski0Stefan M. Fischer1Ulrike Zentgraf2ZMBP, General Genetics, University of Tuebingen, Auf der Morgenstelle 32, Tuebingen 72076, GermanyZMBP, General Genetics, University of Tuebingen, Auf der Morgenstelle 32, Tuebingen 72076, GermanyZMBP, General Genetics, University of Tuebingen, Auf der Morgenstelle 32, Tuebingen 72076, GermanyMassive 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.http://www.mdpi.com/2223-7747/4/3/691senescence regulationGBF1CASEIN KINASE IIphosphorylationphosphorylation mimicry |
| spellingShingle | Anja Smykowski Stefan M. Fischer Ulrike Zentgraf Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 Plants senescence regulation GBF1 CASEIN KINASE II phosphorylation phosphorylation mimicry |
| title | Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 |
| title_full | Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 |
| title_fullStr | Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 |
| title_full_unstemmed | Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 |
| title_short | Phosphorylation Affects DNA-Binding of the Senescence-Regulating bZIP Transcription Factor GBF1 |
| title_sort | phosphorylation affects dna binding of the senescence regulating bzip transcription factor gbf1 |
| topic | senescence regulation GBF1 CASEIN KINASE II phosphorylation phosphorylation mimicry |
| url | http://www.mdpi.com/2223-7747/4/3/691 |
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