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Corpus Systématique Végétale

Titre du document

A second and differentially expressed glutamyl-tRNA reductase gene from Arabidopsis thaliana

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Springer (journals)
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Mots-clés d'auteur
  • HEMA
  • Glu-tRNA reductase
  • Arabidopsis
  • porphyrin
  • chlorophyll
Nom du fichier dans la ressource
  • A. Madan Kumar 1
  • Györgyi Csankovszki 1
  • Dieter Söll 1
  • 1) Department of Molecular Biophysics and Biochemistry, Yale University, 06520-8114, New Haven, CT, USA

5-Aminolevulinic acid (ALA) is the universal precursor of tetrapyrroles (e.g., chlorophylls and hemes). In the chloroplasts of plants and in several eubacterial species ALA is formed in a two-step process known as the C5 pathway. In the first step, glutamyl-tRNA reductase (GluTR), converts glutamate of glutamyl-tRNA to glutamate 1-semialdehyde (GSA) which is rearranged to ALA by glutamate 1-semialdehyde-2,1-aminomutase (GSA-AM) in the second step. Since ALA formation is a limiting step in chlorophyll biosynthesis, GluTR, which is encoded by the HEMA gene in Arabidopsis thaliana plays a vital role in that biosynthesis. Here we report the occurrence of a second functional HEMA gene (HEMA2) in A. thaliana. This gene was isolated by screening a genomic library with a probe from HEMA1. The nucleotide sequence of the cDNA and the corresponding genomic DNA indicates that the Arabidopsis HEMA2 gene contains two short introns (285 bp and 159 bp). The deduced amino acid sequence predicts a HEMA2 protein of 530 amino acids with 79% identity to the HEMA1-encoded GluTR. The 5′-flanking sequence of the HEMA2 gene includes several motifs (e.g., GT-1 boxes, GATA motifs) similar to light-responsive regulatory elements found in light-inducible genes. Unlike the HEMA1 transcript, which is present in all parts of the plant, HEMA2 is expressed in low levels in roots and flowers. The presence of a second functional HEMA gene in Arabidopsis raises the possibility that two C5 pathways exist in chloroplasts.

Catégories Science-Metrix
  • 1 - natural sciences
  • 2 - biology
  • 3 - plant biology & botany
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - physiologie vegetale et developpement
Catégories Scopus
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Plant Science
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Genetics
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Agronomy and Crop Science
  • 1 - Health Sciences ; 2 - Medicine ; 3 - General Medicine
Catégories WoS
  • 1 - science ; 2 - plant sciences
  • 1 - science ; 2 - biochemistry & molecular biology
Identifiant ISTEX

Plant Molecular Biology

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