Transcriptional Regulation of NADP-Dependent Malate Dehydrogenase: Comparative Genetics and Identification of DNA-Binding Proteins

Abstract

The transcriptional regulation of NADP-malate dehydrogenase (NADP-MDH) was analyzed in Arabidopsis ecotypes and other Brassicaceae. The amount of transcript increased twofold after transfer into low temperature (12 degrees C) or high light (750 microE) in all species. Analysis of the genomic DNA reveals that the NADP-MDH gene (At5g58330 in A. thaliana) in Brassicaceae is located between two other genes (At5g58320 and At5g58340 in Arabidopsis), both encoded on the opposite DNA strand. No promoter elements were identified in 5' direction of the NADP-MDH gene, and the expression of NADP-MDH was not affected in knock-out plants carrying a DNA insert in the 5' region. A yeast-one hybrid approach yielded only three DNA-binding proteins for the 500-bp fragment located upstream of the ATG sequence, but 34 proteins for its coding region. However, in Chlamydomonas and in some Poaceae, which do not possess any genes within the 1200 bp upstream region, typical promoter elements were identified. Alignments of genomic DNA reveal that, in contrast to Poaceae, the introns are highly conserved within Brassicaceae. We conclude that in Brassicaceae the majority of regulatory elements are located within the coding region. The NADP-MDH gene of both families evolved from a common precursor, similar to the gene in Chlamydomonas. Changes in the selection pressure allowed the insertion of At5g58340 into the promoter region of a common ancestor. When the demand for transcriptional regulation increased, At5g58340 disappeared in Poaceae, and a promoter developed in the 5' region. In contrast, Brassicaceae maintained At5g58340 and shifted all regulatory elements into the coding region of NADP-MDH.

Fast Retrograde Signaling in Response to High Light Involves Metabolite Export, MITOGEN-ACTIVATED PROTEIN KINASE6, and AP2/ERF Transcription Factors in Arabidopsis

“…Excess reduction capacity can be released to the cytosol via the malate valve using the chloroplast malate dehydrogenase (MDH). The mdh mutant is defective in the chloroplast MDH (Hebbelmann et al, 2012;Supplemental Figure 4A) and unable to activate the malate valve (Hameister et al, 2007). For ERF6, ERF104, and ERF105, similar reaction patterns were observed in the mdh mutants and the wild type (Supplemental Figure 3B).…”

“…Arabidopsis thaliana wild-type Columbia-0 (Col-0) and wild-type Wassilewskija plants and the mutants KatE2 (Oelze et al, 2012), erf6 (SAIL_1236_H11), mdh (Hameister et al, 2007), mpk6-2 (Müller et al, 2010), mpk6-3 (Bethke et al, 2009, stn7 (Pesaresi et al, 2009), tpt1 (Schneider et al, 2002), and tpt2 (Schmitz et al, 2012) were grown in soil culture (1:1:1 mixture of Frühsdorfer Erde Klocke P, perlite, and vermiculite) for 4.5 weeks under the following conditions: 10 h of light, 80 mmol quanta m 22 s 21 , 23°C, and 14 h darkness at 18°C; 55% relative humidity. Except for the KatE2 mutant, all mutants used in this study are T-DNA exon insertion mutants (Supplemental Figure 4).…”

Transfer of a Redox-Signal through the Cytosol by Redox-Dependent Microcompartmentation of Glycolytic Enzymes at Mitochondria and Actin Cytoskeleton

“…Similar effects were demonstrated for the GSSG- and GSNO-treated recombinant cytosolic GAPDH (Holtgrefe et al, 2008), and for cytosolic aldolase from Arabidopsis thaliana (van der Linde et al, 2011), as well as for the S-glutathionylated triose-phosphate isomerase (Ito et al, 2003). Nuclear localization was also reported for the glycolytic isoenzymes from the cytosol (Hameister et al, 2007; Holtgrefe et al, 2008; van der Linde et al, 2011). …”

Cytosolic thiol switches regulating basic cellular functions: GAPDH as an information hub?

“…GapC and thioredoxin h were previously also found to interact in the nucleus of Arabidopsis protoplasts expressing the respective FP-GapC fusion constructs (Scheibe, R., unpublished data). GapC had been identified to bind to the NADP-MDH gene (Hameister et al, 2007), and its transcript and protein level increase upon sustained over-reduction and initial formation of ROS (Becker et al, 2006). A function of nuclear localized GapC might indicate its role as a coactivator for controlling NADP-MDH expression allowing for an increased capacity of the malate-valve required to export and balance excess reducing equivalents in the chloroplast.…”