The redox-sensitive transcription factor Rap2.4a controls nuclear expression of 2-Cys peroxiredoxin A and other chloroplast antioxidant enzymes
1 Plant Biochemistry and Physiology, Bielefeld University, 33501 Bielefeld, Germany
2 Plant Science, Heinrich-Heine-University Düsseldorf, 40225 Düsseldorf, Germany
BMC Plant Biology 2008, 8:48 doi:10.1186/1471-2229-8-48Published: 26 April 2008
The regulation of the chloroplast antioxidant capacity depends on nuclear gene expression. For the 2-Cys peroxiredoxin-A gene (2CPA) a cis-regulatory element was recently characterized, which responds to photosynthetic redox signals.
In a yeast-one-hybrid screen for cis-regulatory binding proteins, the transcription factor Rap2.4a was isolated. Rap2.4a controls the transcript abundance of the prominent chloroplast antioxidant enzyme through binding to the CGCG core of a CE3-like element. Rap2.4a activity is regulated by dithiol/disulfide transition of regulatory cysteinyl residues and subsequent changes in the quaternary structure. The mid-point redox potential of Rap2.4a activation is -269 mV (pH 7.0).
The redox sensitivity of Rap2.4a establishes an efficient switch mechanism for redox control of nuclear gene activity of chloroplast antioxidants, in which Rap2.4 is a redox-sensor and a transducer of redox information.