Abstract
Research on control of in vitro differentiation of stem cells into specific tissues and organs is critical not only for the realization of regenerative medicine, but also for creating experimental model systems for understanding the mechanism of organogenesis. We have been using undifferentiated cells of amphibians to develop in vitro differentiation systems for various tissues and organs by the treatments with activin and other inducers under simple culture conditions. We have been also searching for novel genes and proteins involved in cell differentiation and organ formation by these experimental systems. Recently, by culturing mouse and human embryonic stem cells (ES cells) in serum-free cultures, we have established highly-reproducible experimental systems to control cell differentiation. To search for novel factors that function in nuclear reprogramming of somatic cells, we are using proteomics to analyze protein factors specifically expressed in undifferentiated cells. In addition to developing techniques for controlling differentiation of stem cells, these research projects are useful for creating uniform criteria to evaluate various states of cellular differentiation and to classify various types of cells comprehensively.
