GLN1-1 Antibody

Introduction to GLN1-1 Antibody

The GLN1-1 antibody is a polyclonal rabbit serum antibody specifically designed to target the cytosolic glutamine synthetase isoform GLN1-1 (encoded by AT5G37600 in Arabidopsis thaliana). Glutamine synthetase (GS) plays a pivotal role in nitrogen metabolism by catalyzing the ATP-dependent synthesis of glutamine from glutamate and ammonia. In plants, two major GS isoforms exist: cytosolic (GLN1) and chloroplastic (GLN2). GLN1-1 is one of five cytosolic isoforms encoded by distinct genes in Arabidopsis .

Applications in Research

The GLN1-1 antibody is primarily employed to study the localization, expression levels, and functional redundancy of cytosolic glutamine synthetase isoforms in nitrogen metabolism.

Key Applications

Research Findings and Functional Insights

GLN1-1 is part of a redundant system of cytosolic glutamine synthetases critical for ammonium assimilation. Below are key findings from studies involving GLN1 isoforms:

Functional Redundancy and Isozyme Contributions

• Low Ammonium Conditions: GLN1-1, GLN1-2, and GLN1-3 exhibit overlapping functions, with GLN1-1 contributing to ammonium assimilation in roots .

• High Ammonium Stress: GLN1-2 becomes dominant in shoots, while GLN1-1 supports detoxification in double mutants (gln1-1:gln1-2) .

• Nitrogen Starvation: Triple gln1 knockouts (gln1-1:gln1-2:gln1-3) show severe nitrogen deficiency, highlighting GLN1-1’s role in maintaining amino acid balance .

Tissue-Specific Localization

Promoter–GFP fusion studies reveal distinct expression patterns:

• GLN1-1: Widespread expression in roots and shoots, critical for general ammonium assimilation .

• GLN1-2: Predominant in shoot epidermal cells, specialized for high-affinity ammonium uptake .

Comparative Analysis of GLN1 Isoforms

Limitations and Future Directions

• Specificity Challenges: Cross-reactivity with other GLN1 isoforms may complicate interpretation in complex mutant backgrounds .

• Unresolved Questions: The antibody’s utility in non-Arabidopsis species (e.g., monocots) remains untested.