Threshold Change in Expression of GFP-FABD2 Fusion Protein During Development of Arabidopsis thaliana Leaves

One of the most important technical challenges in cell biology is visualization of the actin cytoskeleton.The widely used GFP-FABD2 fusion protein is a helpful tool for investigating actin architecture in living plants.Here we report our attempt to visualize F-actin in mature leaves of transgenic Arabidopsis thaliana.With a confocal microscope we observed loss of GFP fluorescence in mature Arabidopsis leaves between 19 and 21 days of development.As this pattern was characteristic of all investigated plants and dependent on the age of the plants, we performed precise expression studies at the mRNA (semiquantitative PCR) and protein (Western blot) levels.Our results clearly show a sudden decrease of GFP-FABD2 expression in Arabidopsis leaves after the third week of growth.This means that transgenic Arabidopsis bearing the GFP-FABD2 construct is not a good model system for visualization of the actin cytoskeleton in leaves of mature plants.