Tissue‐specific expression and developmental regulation of cytochrome b561 genes in Arabidopsis thaliana and Raphanus sativus

Verelst, Wim; Kapila, Jyoti; Engler, Janice de Almeida; Stone, Julie M.; Caubergs, R.; Asard, Han

doi:10.1111/j.0031-9317.2004.0235.x

Cited by 9 publications

(3 citation statements)

References 29 publications

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“…Recently, a new member of this protein family was found in the duodenal cells of the small intestine and was shown to have a ferric reductase activity for the trans-plasma membrane uptake of iron , . However, as the genome projects for various organisms progressed, we began to realize that there were many genes encoding proteins homologous to animal cytochrome b 561 in a very wide range of higher plants, such as Arabidopsis thaliana , , Phaseolus vulgaris , and Citrullus lanatus L. . There have been many reports concerning the purification of heme b -containing proteins being characterized by an α-band peak around 561 nm in the visible absorption spectra and high reducibility with AsA from various plants tissues (for a review, see ref ).…”

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confidence: 99%

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

Nakanishi¹,

Rahman²,

Sakamoto

et al. 2009

Biochemistry

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Cytochromes b(561), a novel class of transmembrane electron transport proteins residing in a large variety of eukaryotic cells, have a number of common structural features including six hydrophobic transmembrane alpha-helices and two heme ligation sites. We found that recombinant Zea mays cytochrome b(561) obtained by a heterologous expression system using yeast Pichia pastoris cells could utilize the ascorbate/mondehydroascorbate radical as a physiological electron donor/acceptor. We found further that a concerted proton/electron transfer mechanism might be operative in Z. mays cytochrome b(561) as well upon the electron acceptance from ascorbate to the cytosolic heme center. The well-conserved Lys(83) residue in a cytosolic loop was found to have a very important role(s) for the binding of ascorbate and the succeeding electron transfer via electrostatic interactions based on the analyses of three site-specific mutants, K83A, K83E, and K83D. Further, unusual behavior of the K83A mutant in pulse radiolysis experiments indicated that Lys(83) might also be responsible for the intramolecular electron transfer to the intravesicular heme. On the other hand, pulse radiolysis experiments on two site-specific mutants, S118A and W122A, for the well-conserved residues in the putative monodehydroascorbate radical binding site showed that their electron transfer activities to the monodehydroascorbate radical were very similar to those of the wild-type protein, indicating that Ser(118) and Trp(122) do not have major roles for the redox events on the intravesicular side.

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mentioning

confidence: 99%

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

Nakanishi¹,

Rahman²,

Sakamoto

et al. 2009

Biochemistry

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“…This mechanism would take place rapidly after germination to provide Fe to the developing plant. Indeed, all the partners potentially required for this process, AtATDTX25 , AtCYB1 and AtCYB2 , AtNRAMP3 and AtNRAMP4 are highly expressed in the vascular tissues after germination (Verelst et al ., 2004; Lanquar et al ., 2005).…”

Section: Discussionmentioning

confidence: 99%

AtDTX25, a member of the multidrug and toxic compound extrusion family, is a vacuolar ascorbate transporter that controls intracellular iron cycling in Arabidopsis

et al. 2021

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Summary Iron (Fe) is an essential element, its transport is regulated by the cell redox balance. In seeds, Fe enters the embryo as Fe2+ and is stored in vacuoles as Fe3+. Through its ferric reduction activity, ascorbate plays a major role in Fe redox state and therefore Fe transport within the seed. We searched for ascorbate membrane transporters responsible for controlling Fe reduction by screening the yeast ferric reductase‐deficient fre1 strain and isolated AtDTX25, a member of the Multidrug And Toxic compound Extrusion (MATE) family. AtDTX25 was shown to mediate ascorbate efflux when expressed in yeast and Xenopus oocytes, in a pH‐dependent manner. In planta, AtDTX25 is highly expressed during germination and encodes a vacuolar membrane protein. Isolated vacuoles from AtDTX25‐1 knockout mutant contained less ascorbate and more Fe than wild‐type (WT), and mutant seedlings were highly sensitive to Fe deficiency. Iron imaging further showed that the remobilisation of Fe from vacuoles was highly impaired in mutant seedlings. Taken together, our results established AtDTX25 as a vacuolar ascorbate transporter, required during germination to promote the reduction of the pool of stored Fe3+ and its remobilisation to feed the developing seedling.

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“…Within the pericycle tissue, genes involved in various physiological processes are expressed: thioredoxin [5], biosynthetic enzymes or gene transcripts involved in the initial and final steps of tropane alkaloid biosynthesis [6,7], sulphate transport [8], cytokinin biosynthesis [9,10], morphine biosynthesis [11], ascorbate homeostasis [12], xylem loading of potassium and boron [13,14], etc. But, most importantly, a subset of pericycle cells is giving rise to a new lateral root, which is associated with spatially and temporally controlled gene expression in these cells [15,16].…”

Section: Introductionmentioning

confidence: 99%

In silicoanalyses of pericycle cell populations reinforce their relation with associated vasculature inArabidopsis

Parizot

Roberts

Raes

et al. 2012

Phil. Trans. R. Soc. B

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In Arabidopsis, lateral root initiation occurs in a subset of pericycle cells at the xylem pole that will divide asymmetrically to give rise to a new lateral root organ. While lateral roots never develop at the phloem pole, it is unclear how the interaction with xylem and phloem poles determines the distinct pericycle identities with different competences. Nevertheless, pericycle cells at these poles are marked by differences in size, by ultrastructural features and by specific proteins and gene expression. Here, we provide transcriptional evidence that pericycle cells are intimately associated with their vascular tissue instead of being a separate concentric layer. This has implications for the identification of cell-and tissue-specific promoters that are necessary to drive and/or alter gene expression locally, avoiding pleiotropic effects. We were able to identify a small set of genes that display specific expression in the phloem or xylem pole pericycle cells, and we were able to identify motifs that are likely to drive expression in either one of those tissues.

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Tissue‐specific expression and developmental regulation of cytochrome b561 genes in Arabidopsis thaliana and Raphanus sativus

Abstract: "Tissue-specific expression and developmental regulation of cytochrome b561 genes in Arabidopsis thaliana and Raphanus sativus" (2004). Biochemistry --Faculty Publications. 90.

Cited by 9 publications

References 29 publications

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

AtDTX25, a member of the multidrug and toxic compound extrusion family, is a vacuolar ascorbate transporter that controls intracellular iron cycling in Arabidopsis

In silicoanalyses of pericycle cell populations reinforce their relation with associated vasculature inArabidopsis

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Tissue‐specific expression and developmental regulation of cytochrome b561 genes in Arabidopsis thaliana and Raphanus sativus

Abstract: "Tissue-specific expression and developmental regulation of cytochrome b561 genes in Arabidopsis thaliana and Raphanus sativus" (2004). Biochemistry --Faculty Publications. 90.

Cited by 9 publications

References 29 publications

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b561 for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b561 for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

AtDTX25, a member of the multidrug and toxic compound extrusion family, is a vacuolar ascorbate transporter that controls intracellular iron cycling in Arabidopsis

In silicoanalyses of pericycle cell populations reinforce their relation with associated vasculature inArabidopsis

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Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies

Importance of the Conserved Lysine 83 Residue of Zea mays Cytochrome b₅₆₁ for Ascorbate-Specific Transmembrane Electron Transfer As Revealed by Site-Directed Mutagenesis Studies