The redox-sensitive transcription factor Rap2.4a controls nuclear expression of 2-Cys peroxiredoxin A and other chloroplast antioxidant enzymes.
BACKGROUND
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.


RESULTS
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).


CONCLUSIONS
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.
Shaikhali
Jehad
J
Plant Biochemistry and Physiology, Bielefeld University, 33501 Bielefeld, Germany. jehadgermany@gmx.de
Heiber
Isabelle
I
Seidel
Thorsten
T
Ströher
Elke
E
Hiltscher
Heiko
H
Birkmann
Stefan
S
Dietz
Karl-Josef
KJ
Baier
Margarete
M
D000975:Antioxidants / Q000378:metabolism*; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001665:Binding Sites; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000201:enzymology*; D004269:DNA, Bacterial / Q000378:metabolism; D004777:Environment; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant; D016254:Mutagenesis, Insertional; D010084:Oxidation-Reduction; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D020836:Protein Structure, Quaternary; D021381:Protein Transport; D011523:Protoplasts / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics
D000975:Antioxidants; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D012333:RNA, Messenger; C036483:T-DNA; D014157:Transcription Factors; C493631:2-Cys peroxiredoxin A, Arabidopsis; D054464:Peroxiredoxins