Claire-Lise Meyer

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Nitrate is an important nitrogen source for plants, but also a signal molecule that controls various aspects of plant development. In the present study the role of nitrate on seed dormancy in Arabidopsis was investigated. The effects of either mutations affecting the Arabidopsis nitrate reductase genes or of different nitrate regimes of mother plants on the(More)
Higher plant nitrate reductases (NRs) carry an N-terminal domain whose sequence is not conserved in NRs from other organisms. A gene composed of a full-length tobacco NR cDNA with an internal deletion of 168 bp in the 5' end fused to the cauliflower mosaic virus 35S promoter and appropriate termination signals was constructed and designated as delta NR. An(More)
The retinal receptor rhodopsin undergoes a conformational change upon light excitation to form metarhodopsin II (Meta II), which allows interaction and activation of its cognate G protein, transducin (G(t)). A C-terminal 11-amino acid peptide from transducin, G(talpha)-(340-350), has been shown to both bind and stabilize the Meta II conformation, mimicking(More)
We estimated the level of quantitative polymorphism for zinc (Zn) tolerance in neighboring metallicolous and nonmetallicolous populations of Arabidopsis halleri and tested the hypothesis that divergent selection has shaped this polymorphism. A short-term hydroponic test was used to capture the quantitative polymorphism present between edaphic types, among(More)
Higher plant nitrite reductase (NiR) is a monomeric chloroplastic protein catalysing the reduction of nitrite, the product of nitrate reduction, to ammonium. The expression of this enzyme is controlled at the transcriptional level by light and by the nitrogen source. In order to study the post-transcriptional regulation of NiR, Nicotiana plumbaginifolia and(More)
There is huge variability among populations of the hyperaccumulator Noccaea caerulescens (formerly Thlaspi caerulescens) in their capacity to tolerate and accumulate cadmium. To gain new insights into the mechanisms underlying this variability, we estimated cadmium fluxes and further characterized the N. caerulescens heavy metal ATPase 4 (NcHMA4) gene in(More)
Tobacco nitrate reductase (NR) produced in yeast retains cytochrome c reductase activity, but not NR activity. Biochemical data suggest that the haem and FAD domains are functional, and that the molybdenum cofactor (MoCo) domain is inactive owing to the absence of MoCo in yeast. The native form of the produced NR is dimeric. Thus MoCo is not involved in NR(More)
We have analyzed four Nicotiana plumbaginifolia null mutants presumably affected in the heme domain of nitrate reductase. The DNA sequence of this domain has been determined for each mutant and for the wild type. Two mutations were identified as single base changes leading to, respectively, the substitution of a histidine residue by an asparagine (mutant(More)
Most organisms appear to have a molybdenum cofactor consisting of a complex of molybdenum and a pterin derivative. Very little is known about molybdenum cofactor biosynthesis in plants or other eukaryotes, because the instability of the cofactor and its precursors makes it difficult to analyze this pathway. We have isolated two cDNA clones from the higher(More)
Nitrate reductase (NR) is post-translationally regulated by phosphorylation and binding of 14-3-3 proteins. Deletion of 56 amino acids in the amino-terminal domain of NR was previously shown to impair this type of regulation in tobacco (Nicotiana plumbaginifolia) (L. Nussaume, M. Vincentez, C. Meyer, J.-P. Boutin, M. Caboche [1995] Plant Cell 7: 611-621),(More)