Cloning and characterization of a novel Mg(2+)/H(+) exchanger.
نویسندگان
چکیده
Cellular functions require adequate homeostasis of several divalent metal cations, including Mg(2+) and Zn(2+). Mg(2+), the most abundant free divalent cytoplasmic cation, is essential for many enzymatic reactions, while Zn(2+) is a structural constituent of various enzymes. Multicellular organisms have to balance not only the intake of Mg(2+) and Zn(2+), but also the distribution of these ions to various organs. To date, genes encoding Mg(2+) transport proteins have not been cloned from any multicellular organism. We report here the cloning and characterization of an Arabidopsis thaliana transporter, designated AtMHX, which is localized in the vacuolar membrane and functions as an electrogenic exchanger of protons with Mg(2+) and Zn(2+) ions. Functional homologs of AtMHX have not been cloned from any organism. Ectopic overexpression of AtMHX in transgenic tobacco plants render them sensitive to growth on media containing elevated levels of Mg(2+) or Zn(2+), but does not affect the total amounts of these minerals in shoots of the transgenic plants. AtMHX mRNA is mainly found at the vascular cylinder, and a large proportion of the mRNA is localized in close association with the xylem tracheary elements. This localization suggests that AtMHX may control the partitioning of Mg(2+) and Zn(2+) between the various plant organs.
منابع مشابه
Synthesis, Characterization and Application of a Novel Zirconium Phosphonate Ion-Exchanger for Removal of Ni2+, Cu2+ and Zn2+ from Aqueous Solutions
A new category of hybrid organic-inorganic zirconium phosphonate, Zr[(O3PCH2)2NC6H4CO2H].2H2O was synthesized and the applicability of the prepared sorbent as an ion-exchanger for removal of Ni2+, Cu2+ and Zn2+ from aqueous solutions was evaluated. The characterization of the synthe...
متن کاملCloning and molecular characterization of TaERF6, a gene encoding a bread wheat ethylene response factor
Ethylene response factor proteins are important for regulating gene expression under different stresses. Different isoforms for ERF have previously isolated from bread wheat (Triticum aestivum L.) and related genera and called from TaERF1 to TaERF5. We isolated, cloned and molecular characterized a novel one based on TdERF1, an isoform in durum wheat (Tri...
متن کاملCloning, Expression and Characterization of Recombinant Exotoxin A-Flagellin Fusion Protein as a New Vaccine Candidate against Pseudomonas aeruginosa Infections
Background: Infections due to Pseudomonas aeruginosa are among the leading causes of morbidity and mortality in patients who suffer from impaired immune responses and chronic diseases such as cystic fibrosis. At present, aggressive antibiotic therapy is the only choice for management of P. aeruginosa infections, but emergence of highly resistant strains necessitated the development of novel alt...
متن کاملMolecular Cloning and Characterization of a Lipase from an Indigenous Bacillus pumilus
Cloning and sequencing of a lipase gene from an indigenous Bacillus pumilus, strain F3, revealed an open-reading frame of 648 nucleotides predicted to encode a protein of 215 residues. Sequence analysis showed that F3 lipase contained a signal peptide composed of 34 amino acids with an H domain of 18 residues. A tat-like motif was found in the signal peptide similar to some other Bacillus pumil...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The EMBO journal
دوره 18 14 شماره
صفحات -
تاریخ انتشار 1999