Our main research topic is to decipher the mechanism how cells differentiate into diverse shapes and functions in multicellular organisms. All the plant and animal individuals originate from a single fertilized egg (zygote), but the cells origiated from it acquire different fates. The fundamental tool for this cell differentiation process is the cell type-specifi gene expression. All the cells in a multicellular organism in different share the same genome, but the expression (transcription and translation) of different set of the genome leads each cell to a specific shape and function. The first research topic in our lab is to study the regulatory mechanism of cell type-specific gene expression. The second topic is to characterize how hormones play for cell differentiation. Our model hormone is auxin that is a representative plant hormone. Auxin works as a morphogen to modulate the differentiation of cells, tissues, and organs by building local concentration gradients. The local auxin gradient can be formed by cell-to-cell movement of auxin in a dirctional way which is enabled by asymetrical localization of auxin transporter in the plasma membrane. This auxin polar transport is likely to be operational during land plant evolution from simple mosses to angiosperms that have moe complex tissue organization. In regard with auxin transport, our goal is to know molecular action mechanism of auxin transporting proteins and evolution of auxin transporters. Another research topic regarding auxin action is the auxin signaling pathway for cell differentiation wth the root hair cell as a model system.