THE KERATIN INTERMEDIATE FILAMENTLIKE SYSTEM IN THE PLANT MESOPHYLL CELLS

A delicate intermediate filament-like network of mesophyll cells was observed both in maize and tobacco, using selective extraction together with whole-mount cell preparation for electron microscopy. The filament of the network is about 10 nm in diameter. Further test using immuno-gold labeling with anti-keratin antibodies indicated that the component of the intermediate filament-like system was keratin-like protein. Such a keratin-like intermediate filament system existing in plant cells was demonstrated for the first time. Meanwhile, 3-nm size filaments and their connection with 10-nm filaments were also shown in maize and tobacco protoplasts.