Arabidopsis MEKK1 can take a short cut: it can directly interact with senescence-related WRKY53 transcription factor on the protein level and can bind to its promoter

Despite the importance of the senescence processes in plants, our knowledge on regulatory mechanisms of senescence is still poor

Ying Miao

2007

Scholarcy highlights

  • Despite the importance of the senescence processes in plants, our knowledge on regulatory mechanisms of senescence is still poor
  • WRKY transcription factors have been shown to be involved in the regulation of leaf senescence
  • Almost nothing is known about the upstream regulation of the senescence specific expression of WRKY factors
  • We characterized proteins that bind and activate the promoter of WRKY53, which participates in leaf senescence in Arabidopsis thaliana
  • The binding motif for MEKK1 in the WRKY53 promoter could be characterized and promoter:GUS analyses revealed that this region is important for the switch of WRKY53 expression from a leaf age dependent to a systemic plant age dependent expression during bolting time
  • MEKK1 could phosphorylate WRKY53 in vitro and phosphorylation could increase DNA-binding activity of WRKY53 in vitro and transcription of a WRKY53 promoter driven reporter gene in vivo. These results suggest that MEKK1 is a bifunctional protein: it binds to the promoter of the WRKY53 gene regulating the switch from a leaf age dependent to a plant age dependent expression and it can phosopharylate WRKY53 in vitro increasing its DNA binding activity
  • MEKK1 might be able to take a very direct short cut in mitogen-activated protein kinase signalling by directly phosphorylating a transcription factor

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