Rat Kangaroo Cell Intermediate Filaments

Y-2E/C Bandpass Emission (Medium Bandwidth Excitation) Yellow Set

Fluorescence emission intensity from a culture of rat kangaroo kidney (PtK2 line) epithelial cells that were immunofluorescently labeled with primary anti-keratin (an intermediate filament protein) mouse monoclonal antibodies followed by goat anti-mouse Fab fragments conjugated to the cyanine dye, Cy3. The visible light absorption maximum of Cy3 is 552 nanometers and the emission maximum occurs at 570 nanometers. Keratins represent a class of water-insoluble proteins that form monofilaments, a category of intermediate filament that is present in the cytoskeletal structure. In addition, the specimen was simultaneously stained for nuclear DNA with DAPI. Note the absence of signal from the blue fluorophore (DAPI), which is not efficiently excited by yellow light, but the high level of orange-red fluorescence intensity from the Cy3-labeled keratin intermediate filament network.