References of "Hanikenne, Marc"
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See detailVitellogenin and vitellogenin receptor gene expression and 20-hydroxyecdysone concentration in Macrobrachium rosenbergii exposed to chlordecone
Lafontaine, Anne ULg; Hanikenne, Marc ULg; Boulangé-Lecomte, Céline et al

in Environmental Science and Pollution Research (2016)

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See detailMetal binding to the N-terminal cytoplasmic domain of the PIB ATPase HMA4 is required for metal transport in Arabidopsis.
Laurent, Clémentine ULg; Lekeux, Gilles ULg; Ukuwela, Ashwinie A et al

in Plant Molecular Biology (2016), 90

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding ... [more ▼]

PIB ATPases are metal cation pumps that transport metals across membranes. These proteins possess N- and C-terminal cytoplasmic extensions that contain Cys- and His-rich high affinity metal binding domains, which may be involved in metal sensing, metal ion selectivity and/or in regulation of the pump activity. The PIB ATPase HMA4 (Heavy Metal ATPase 4) plays a central role in metal homeostasis in Arabidopsis thaliana and has a key function in zinc and cadmium hypertolerance and hyperaccumulation in the extremophile plant species Arabidopsis halleri. <br />Here, we examined the function and structure of the N-terminal cytoplasmic metal-binding domain of HMA4. We mutagenized a conserved CCTSE metal-binding motif in the domain and assessed the impact of the mutations on protein function and localization in planta, on metal-binding properties in vitro and on protein structure by Nuclear Magnetic Resonance spectroscopy. <br />The two Cys residues of the motif are essential for the function, but not for localization, of HMA4 in planta, whereas the Glu residue is important but not essential. These residues also determine zinc coordination and affinity. Zinc binding to the N-terminal domain is thus crucial for HMA4 protein function, whereas it is not required to maintain the protein structure. <br />Altogether, combining in vivo and in vitro approaches in our study provides insights towards the molecular understanding of metal transport and specificity of metal P-type ATPases. [less ▲]

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See detailFunctional characterization of FRD3,  a citrate transporter, in Arabidopsis relatives
Scheepers, Maxime ULg; Charlier, Jean-Benoit; Spielmann, Julien ULg et al

Poster (2015, December 03)

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene ... [more ▼]

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene encodes FRD3, a member of the MATE family of membrane transporters (56 members in A. thaliana). It is a citrate transporter involved in iron homeostasis (4-6) and playing a role in zinc tolerance in A. thaliana (7). We are aiming to analyse the FRD3 high expression in A. halleri and the FRD3 function in zinc and iron homeostasis in A. thaliana. [less ▲]

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See detailThe evolution of metal hyperaccumulation in Arabidopsis halleri
Hanikenne, Marc ULg

Scientific conference (2015, August 07)

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See detailTowards the identification of cis-elements responsible for the high expression of HMA4, an essential gene for Zn hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Conference (2015, June 26)

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals ... [more ▼]

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals. The Zn/Cd plasmamembrane pump HMA4 (heavy metal ATPase 4) plays a central role in this process and is involved in xylem loading/unloading. Moreover, HMA4 is overexpressed in A. halleri compare to its non-tolerant and non-hyperaccumulator sister, Arabidopsis thaliana. The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies. In this study, we are focusing on the two most active HMA4 promoters and we aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. Through deletion analysis, two important regions for a high expression have been identified. Ongoing analysis of more detailed deletions will be presented. [less ▲]

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See detailTowards the identification of mechanisms underlying the high expression of HMA4, an essential gene for zinc hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Poster (2015, June 08)

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and ... [more ▼]

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and storage processes. In this network, transporters have a central role. To study the molecular basis of zinc homeostasis in plants, we are using A. halleri, a zinc- and cadmium-tolerant and zinc-hyperaccumulating species representing the extreme end of natural variation in terms of metal homeostasis. Indeed, A. halleri stores high amount of metals in vacuoles of above-ground tissues (>1% Zn or 0.01% Cd in shoot dry weight). Cross-species transcriptomic studies identified about thirty genes which are constitutively over-expressed in A. halleri compared to its non-tolerant and non-hyperaccumulator sister species, Arabidopsis thaliana (1-3). HMA4 is one of these genes. It encodes a Zn/Cd plasmamembrane pump involved in xylem loading/unloading which is a key step in the hyperaccumulation process (4-5). The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies (5). We aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. [less ▲]

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See detailMechanisms of metal hyperaccumulation: gene regulation in Arabidopsis halleri
Hanikenne, Marc ULg

Conference (2015, June 08)

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See detailExpression study of FRD3 in Arabidopsis relatives
Scheepers, Maxime ULg; Charlier, Jean-Benoit ULg; Spielmann, Julien ULg et al

Poster (2015, June 08)

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene ... [more ▼]

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene encodes FRD3, a member of the MATE family of membrane transporters (56 members in A. thaliana). It is a citrate transporter involved in iron homeostasis (4-6) and playing a role in zinc tolerance in A. thaliana (7). We are aiming to analyse the FRD3 high expression in A. halleri and the FRD3 function in zinc and iron homeostasis in A. thaliana. [less ▲]

Detailed reference viewed: 65 (11 ULg)
See detailFunctional analysis of FRD3 in Arabidopsis
Scheepers, Maxime ULg; Charlier, Jean-Benoit ULg; Spielmann, Julien ULg et al

Poster (2015, June)

Zinc and iron are two essential micronutrients for plants. The homeostasis networks of the two metals are intertwined. The FRD3 (FERRIC REDUCTASE DEFECTIVE 3) protein, a member of the MATE family of ... [more ▼]

Zinc and iron are two essential micronutrients for plants. The homeostasis networks of the two metals are intertwined. The FRD3 (FERRIC REDUCTASE DEFECTIVE 3) protein, a member of the MATE family of membrane transporters, is a citrate transporter involved in iron homeostasis and playing a role in zinc tolerance in Arabidopsis. The FRD3 gene displays a complex regulation. Alternative transcript initiation for FRD3 determines two transcripts, which differ in their 5'UTRs and have differential translation efficiency. The two transcripts are selectively regulated under stress conditions: iron and zinc depletion, zinc excess or cadmium presence. We are aiming to determine the FRD3 function in zinc and iron homeostasis in Arabidopsis. We will present data (i) on the functional characterization of the alternative transcripts and their role in metal homeostasis in Arabidopsis and (ii) on the zinc phenotypes of the frd3 mutant. [less ▲]

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See detailTowards the identification of cis-elements responsible for the high expression of HMA4, an essential gene for zinc hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Poster (2015, May 13)

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals ... [more ▼]

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals. The Zn/Cd plasmamembrane pump HMA4 (heavy metal ATPase 4) plays a central role in this process and is involved in xylem loading/unloading. Moreover, HMA4 is overexpressed in A. halleri compare to its non-tolerant and non-hyperaccumulator sister, Arabidopsis thaliana. The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies. In this study, we are focusing on the two most active HMA4 promoters and we aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. Through deletion analysis, two important regions for a high expression have been identified. Ongoing analysis of more detailed deletions will be presented. [less ▲]

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See detailZinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives
Charlier, Jean_Benoit; Polese, Catherine; Nouet, Cécile ULg et al

in Journal of Experimental Botany (2015), 66

In Arabidopsis thaliana, FRD3 (Ferric Chelate Reductase Defective 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in ... [more ▼]

In Arabidopsis thaliana, FRD3 (Ferric Chelate Reductase Defective 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of GUS and GFP reporter constructs to compare the expression profile, transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes display a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determine transcript variants which are differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation. [less ▲]

Detailed reference viewed: 24 (7 ULg)