Knockout mutants as a tool to identify the subunit composition of Arabidopsis glutamine synthetase isoforms
2014
Autori:
Dragicevic, MilanTodorović, Slađana
Bogdanović, Milica
Filipović, Biljana
Music, Danijela
Simonović, Ana
Tip dokumenta:
Članak u časopisu (Objavljena verzija)
Metapodaci
Prikaz svih podataka o dokumentuApstrakt:
Glutamine synthetase (GS) is a key enzyme in nitrogen assimilation,
which catalyzes the formation of glutamine from ammonia and glutamate.
Plant GS isoforms are multimeric enzymes, recently shown to be decamers.
The Arabidopsis genome encodes five cytosolic (GS1) proteins labeled as
GLN1;1 through GLN1; 5 and one chloroplastic (GS2) isoform, GLN2;0.
However, as many as 11 GS activity bands were resolved from different
Arabidopsis tissues by Native PAGE and activity staining. Western
analysis showed that all 11 isoforms are composed exclusively of 40 kDa
GS1 subunits. Of five GS1 genes, only GLN1;1, GLN1;2 and GLN1;3
transcripts accumulated to significant levels in vegetative tissues,
indicating that only subunits encoded by these three genes produce the
11-band zymogram. Even though the GS2 gene also had significant
expression, the corresponding activity was not detected, probably due to
inactivation. To resolve the subunit composition of 11 active GS1
isoforms, homozygous knockout mutants deficient in the expression of
different GS1 genes were selected from the progeny of T-DNA insertional
SALK and SAIL lines. Comparison of GS isoenzyme patterns of the selected
GS1 knockout mutants indicated that all of the detected isoforms consist
of varying proportions of GLN1;1, GLN1;2 and GLN1;3 subunits, and that
GLN1 :1 and GLN1;3, as well as GLN1;2 and GLN1;3 and possibly GLN1;1 and
GLN1;2 proteins combine in all proportions to form active homo- and
heterodecamers. (C) 2014 Elsevier Masson SAS. All rights reserved.
Ključne reči:
Glutamine synthetase; Knockout mutants; T-DNA insertion; Subunit composition; Arabidopsis thaliana; IsoformsIzvor:
Plant Physiology and Biochemistry, 2014, 79, 1-9
DOI: 10.1016/j.plaphy.2014.02.023
ISSN: 0981-9428