Abstract
tonsoku (tsk) mutants of Arabidopsis thaliana show abnormal structure in both shoot and root apical meristems. In the meristem of tsk plants, expression of several meristem-specific genes show abnormal expression patterns, and cells dividing to abnormal direction are observed. It seems that abnormal direction of cell division in the meristem of tsk plants leads to disorganized meristem structure. Since TSK protein with 1311 amino acids has LGN repeats and Leucine-Rich repeats involved in protein-protein interactions, TSK might serve as a core of a protein complex with unknown cellular function. We expressed TSK protein fused with GFP at its N- or C-terminus in tobacco BY-2 cells and analyzed their cellular localization. Both of the TSK/GFP fusion proteins were found to be targeted to nucleus and localized in the nucleoplasm. Subcellular fractionation of transformed BY-2 cells and subsequent Western-blot analysis with TSK antibody also supported the nuclear localization of the fusion proteins.
