GIF1 Antibody

Introduction to GIF1 Antibody

GIF1 (GRF-INTERACTING FACTOR 1) antibodies are specialized tools used to detect and study the GIF1 protein, a transcriptional coactivator critical for regulating growth and development in plants and mammals. GIF1 interacts with GROWTH-REGULATING FACTOR (GRF) proteins to form functional complexes that modulate gene expression, cell proliferation, and organ morphogenesis . These antibodies enable researchers to investigate GIF1's roles in leaf development, shoot architecture, and cell cycle regulation through techniques like immunoblotting, co-immunoprecipitation (co-IP), and fluorescence imaging .

Molecular Structure and Functional Domains

GIF1 contains two conserved domains essential for its activity:

• SNH domain (SYT N-terminal homology): Mediates interaction with GRF proteins through their QLQ domains .

• QG domain (QPGY-rich domain): Exhibits transactivation activity in yeast systems and is critical for transcriptional regulation .

Interaction mechanism:

• GIF1 binds directly to GRF1 via its SNH domain, while GRF1’s QLQ domain facilitates this interaction .

• The GIF1-GRF complex recruits chromatin-remodeling SWI/SNF complexes (e.g., BRAHMA) to regulate target gene expression .

Arabidopsis thaliana

• Phenotype: gif1 mutants exhibit narrow leaves and petals with 40–50% fewer cells, indicating GIF1’s role in cell proliferation .

• Genetic interaction: GIF1 and GRF1 co-localize in nuclear speckles and activate genes involved in cell cycle progression .

• Expression: GIF1 is highly expressed in shoot apical meristems, roots, and flowers but weakly in mature leaves .

Zea mays (Maize)

• Mutant analysis: gif1 mutants display compact shoots, reduced tassel branching, and disrupted meristem function .

• Molecular role: Maize GIF1 regulates transcripts of key meristem genes like knotted1 and liguleless2 .

Human Cell Studies

• Cell cycle regulation: Overexpression of GIF1 in human fibroblasts (HS27, HS68) induces G1 phase arrest, suggesting a tumor-suppressive role .

• Protein interactions: GIF1 binds GADD45α and nuclear receptors (e.g., Nur77, androgen receptor), repressing their transcriptional activity .

Table 1: GIF1 Functional Roles Across Species

Applications in Biological Research

GIF1 antibodies are widely used for:

• Protein localization: Confocal microscopy in tobacco leaves revealed nuclear speckling of GIF1-EYFP fusions .

• Western blotting: Detects GIF1 in plant and human lysates (e.g., 43-kDa monomer in Arabidopsis) .

• Co-IP assays: Validates interactions with GRF1, GADD45α, and chromatin remodelers .

• Mutant validation: Identifies gif1 splicing mutants (e.g., 13-bp deletion in Setaria italica) .

Table 2: Key Antibody Applications