Abstract
Intermediate filaments (IFs) are known as a kind of cytoskeletons in animal cells. However, genes which encode a protein constituting IFs in plant cells have never been identified. Our purpose is identification of the IF protein gene in plant cells. Nine genes, deduced amino acid sequence of which has homology to that of human intermediate filament proteins, were selected in a database of complete genome sequence for Arabidopsis. We designated these genes plant IF motif protein genes. One of plant IF motif protein-GFP fusions expressed in transgenic tobacco BY-2 cells formed filament-like structure in cytoplasm around nuclei in interphase. This filament-like structure did not colocalize with microtubules or actin filaments. In mitotic phase, this protein localized near cell plate and spindle, indicating that this protein colocalizes with microtubules. The gene encoding this protein was expressed in root apex, shoot apex, vein and water pore of Arabidopsis seedlings.