Premium
Dark‐induced and organ‐specific expression of two asparagine synthetase genes in Pisum sativum.
Author(s) -
Tsai F.Y.,
Coruzzi G.M.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb08114.x
Subject(s) - biology , pisum , asparagine synthetase , sativum , gene , asparagine , glutamine synthetase , microbiology and biotechnology , genetics , biochemistry , enzyme , glutamine , amino acid , botany
Nucleotide sequence analysis of cDNAs for asparagine synthetase (AS) of Pisum sativum has uncovered two distinct AS mRNAs (AS1 and AS2) encoding polypeptides that are highly homologous to the human AS enzyme. The amino‐terminal residues of both AS1 and AS2 polypeptides are identical to the glutamine‐binding domain of the human AS enzyme, indicating that the full‐length AS1 and AS2 cDNAs encode glutamine‐dependent AS enzymes. Analysis of nuclear DNA shows that AS1 and AS2 are each encoded by single genes in P.sativum. Gene‐specific Northern blot analysis reveals that dark treatment induces high‐level accumulation of AS1 mRNA in leaves, while light treatment represses this effect as much as 30‐fold. Moreover, the dark‐induced accumulation of AS1 mRNA was shown to be a phytochrome‐mediated response. Both AS1 and AS2 mRNAs also accumulate to high levels in cotyledons of germinating seedlings and in nitrogen‐fixing root nodules. These patterns of AS gene expression correlate well with the physiological role of asparagine as a nitrogen transport amino acid during plant development.