Abstract
Importin β mediates the nuclear transport of proteins containing the nuclear localization signal (NLS). A trimeric complex, which consists of importin α /β and NLS-containing protein, is formed in the cytoplasm and migrates into the nucleoplasm through NPC in an importin β-dependent manner. To elucidate the mechanism of nuclear transport in plant cells, we isolated two cDNA encoding importin β from rice plant. Since the presence of two importin β genes was shown for the first time among a variety of eukaryotes, we are interested in the biological meaning of two importin βs. To address it, we carried three type of experiments: (1) Observation of the subcellular localization of them by using GFP fusion protein (2) GST pulldown assay to examine the interaction between rice importin αs and them (3) Northern hybridization analysis of their gene expression. The results indicate that two rice importin βs differentiate in their biological functions.
