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The regulatory PII protein controls arginine biosynthesis in Arabidopsis
Author(s) -
Ferrario-Méry Sylvie,
Besin Evelyne,
Pichon Olivier,
Meyer Christian,
Hodges Michael
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.02.075
Subject(s) - arabidopsis , biochemistry , mutant , arginine , biosynthesis , biology , citrulline , arabidopsis thaliana , transcriptome , ornithine , gene , microbiology and biotechnology , gene expression , amino acid
In higher plants, PII is a nuclear‐encoded plastid protein which is homologous to bacterial PII signalling proteins known to be involved in the regulation of nitrogen metabolism. A reduced ornithine, citrulline and arginine accumulation was observed in two Arabidopsis PII knock‐out mutants in response toNH 4 +resupply after N starvation. This difference could be explained by the regulation of a key enzyme of the arginine biosynthesis pathway, N ‐acetyl glutamate kinase (NAGK) by PII. In vitro assays using purified recombinant proteins showed the catalytic activation of Arabidopsis NAGK by PII giving the first evidence of a physiological role of the PII protein in higher plants. Using Arabidopsis transcriptome microarray (CATMA) and RT‐PCR analyses, it was found that none of the genes involved in the arginine biosynthetic or catabolic pathways were differentially expressed in a PII knock‐out mutant background. In conclusion, the observed changes in metabolite levels can be explained by the reduced activation of NAGK by PII.