β-Catenin up-regulates Nanog expression through interaction with Oct-3/4 in embryonic stem cells

It is well known that mouse embryonic stem (ES) cells can be maintained by the presence of leukemia inhibitory factor (LIF). Recent studies have revealed that Wnt also exhibits activity similar to LIF. The molecular mechanism behind the maintenance of ES cells by these factors, however, is not fully understood. In this study, we found that LIF enhances level of nuclear β-catenin, a component of the Wnt signaling pathway. Expression of an activated mutant of β-catenin led to the long-term proliferation of ES cells, even in the absence of LIF. Furthermore, it was found that β-catenin up-regulates Nanog in an Oct-3/4-dependent manner and that β-catenin physically associates with Oct-3/4. These results suggest that up-regulating Nanog through interaction with Oct-3/4 involves β-catenin in the LIF- and Wnt-mediated maintenance of ES cell self-renewal.